Pollution in the coastal areas negatively affects biochemical indicators of seawater, human health and marine organisms. Hai Phong is a coastal city of Vietnam with the development of socio-economic activities, repres...Pollution in the coastal areas negatively affects biochemical indicators of seawater, human health and marine organisms. Hai Phong is a coastal city of Vietnam with the development of socio-economic activities, representing through an increasing number of industrial zones. This study is to evaluate the pollution of large industrial zones in Hai Phong city using numerical models. The numerical simulation (MIKE 21 SW, FM, ECO Lab) models were applied to simulate the wave propagation, hydraulic regime, water quality in coastal Hai Phong area. The MIKE 21 ECO Lab model was used to evaluate sources of waste from the large coastal industrial zones to some aquaculture zones. The calibration and validation results of wave propagation and the hydrodynamic models were resonably good, with Nash coefficient ranging from 0.65 to 0.90 and a percent bias (PBIAS) from 5.6% to 9.4%. The simulation results of water quality and concentration of pollutants (DO, BOD<sub>5</sub>, COD, TSS, Fe, and Coliform) in 2023 at the aquaculture locations show that the BOD<sub>5</sub>, COD, and TSS concentrations were higher than the allowable limits stated in the national technical regulation on surface water quality (QCVN 08:2023/BTNMT) and lower than the allowable limits stated in the national technical regulation on marine water quality (QCVN 10:2023/BTNMT). The outcomes of this study will provide more information to support managers to come up with a better socio-economic development plan for Hai Phong city to achieve sustainable development.展开更多
Biomass and carbon stock in a forested areas are now prime important indicators of forest management and climate change mitigation measures. But the accurate estimation of biomass and carbon in trees of forests is now...Biomass and carbon stock in a forested areas are now prime important indicators of forest management and climate change mitigation measures. But the accurate estimation of biomass and carbon in trees of forests is now a challenging issue. In most cases, pantropical and regional biomass models are used frequently to estimate biomass and carbon stock in trees, but these estimation</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> have some uncertainty compared to the species-specific allometric biomass model. </span><i><span style="font-family:Verdana;">Acacia</span></i><span> <i><span style="font-family:Verdana;">nilotica</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Casuarina</span></i> <i><span style="font-family:Verdana;">equisetifolia</span></i></span><span style="font-family:Verdana;"> and </span><i><span style="font-family:Verdana;">Melia</span></i><span style="font-family:Verdana;"> <i>azedarach</i> </span><span style="font-family:Verdana;">have been planted in different areas of Bangladesh considering the species-specific site requirements. While </span><i><span style="font-family:Verdana;">Barringtonia</span></i><span style="font-family:Verdana;"> <i>acutangula</i></span><span style="font-family:Verdana;"> and </span><i><span style="font-family:Verdana;">Pongamia</span></i><span style="font-family:Verdana;"> <i>pinnata</i> </span><span style="font-family:Verdana;">are the dominant tree species of the freshwater swamp forest of Bangladesh. This study was aimed to develop species-specific allometric biomass models for estimating stem and above ground biomass (TAGB) of these species using the non-destructive method and to compare the efficiency of the derived biomass models with the frequently used regional and pantropical biomass models. Four Ln-based models with diameter at breast height (DBH) and total height (H) were tested to derive the best fit allometric model. Among the tested models, Ln (biomass) = a + b Ln (D) + c Ln (H) was the best-fit model for </span><i><span style="font-family:Verdana;">A</span></i><span><span style="font-family:Verdana;">. </span><i><span style="font-family:Verdana;">nilotica</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">M</span></i><span style="font-family:Verdana;">. </span><i><span style="font-family:Verdana;">azedarach</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">B</span></i><span style="font-family:Verdana;">. </span><i><span style="font-family:Verdana;">acutangula</span></i> </span><span style="font-family:Verdana;">and</span><span> <i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;">. </span><i><span style="font-family:Verdana;">pinnata</span></i> </span><span style="font-family:Verdana;">and Ln (biomass) = a + b Ln (D</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">H) was best-fit for </span><i><span style="font-family:Verdana;">C</span></i><span><span style="font-family:Verdana;">. </span><i><span style="font-family:Verdana;">equisetifolia</span></i><span style="font-family:Verdana;">. </span></span><span style="font-family:Verdana;">Finally</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> the derived best-fit species-specific TAGB models have shown superiority over the other frequently used pantropical and regional biomass models in relation to model efficiency and model prediction error.展开更多
Marine science technology innovation provides power and guarantees for marine eco-civilization construction,which provides direction and material support for marine science technology innovation.Therefore,the coordina...Marine science technology innovation provides power and guarantees for marine eco-civilization construction,which provides direction and material support for marine science technology innovation.Therefore,the coordinated development of the two is of great significance to the marine economy sustainable development in China’s coastal areas.On the basis of clarifying the connotations of marine science technology innovation and marine eco-civilization in China’s coastal areas from 2006 to 2019,the mechanism for their coordinated development was analysed.A comprehensive indicator system based on the connotation of the two was constructed,and the coordinated development relationship was empirically tested using the coupled coordination model and the panel vector autoregressive(PVAR)model.The results show that:1)the level of China’s coastal marine science technology innovation continues to improve,gradually forming the core of the development of marine science technology innovation in the north,east and south of Shandong,Shanghai and Guangdong;the level of marine eco-civilization development fluctuating upward trend,showing obvious spatial differentiation characteristics.2)The degree of coordination of marine science technology innovation and marine eco-civilization is growing over time.There is no causal relationship between marine science technology innovation and marine eco-civilization in the northern marine economic circle,but there is a two-way causal relationship between the two in the eastern and southern marine economic circles.3)Marine eco-civilization shows a significant positive and continuous impact on marine science technology innovation,and marine science technology innovation shows a long-term,continuous,fluctuating,and lagging impact on marine eco-civilization.The overall role of marine eco-civilization on marine science technology innovation is dominant,and there are significant differences in the impact effects of the two major marine economic circles.展开更多
The Coastal Zone Management Act was finally promulgated in 2015,while Ministry of the Interior was asked to draft a coastal management act in 1991 by Executive Yuan.It was until the government’s lifting of martial la...The Coastal Zone Management Act was finally promulgated in 2015,while Ministry of the Interior was asked to draft a coastal management act in 1991 by Executive Yuan.It was until the government’s lifting of martial law in 1987,vigorous activities started prevailing on coastal areas.And relevant legal documents were on sea reclamation for development in the 1980’s by Council of Agriculture.The approval of“Taiwan Coastal Area Natural Environment Protection Plan”showed an era of environmental protection in 1980s.However,it was surely not market driven,similar to land development,but some efforts by the administration systems.Through all the years,the efforts were put on drafting plans and these efforts were not quite sounding.The coastal disasters and further climate change caught the attention of relevant NGOs,scholars,politicians,and the society.At the critical juncture the government was made to react to outside demands.And then the Coastal Zone Management Act was passed by Legislative Yuan,establishing an integrated coastal management system in Taiwan.As such,it is proposed to look into this long process of the attempt with the concept of institutional change in order to understand this coastal environmental preservation and protection issue in a broader scope.展开更多
Understanding the relative roles of local environmental effects and spatial effects on phytoplankton community is of essential importance to study the biogeography of them at regional scale. However, the determinants ...Understanding the relative roles of local environmental effects and spatial effects on phytoplankton community is of essential importance to study the biogeography of them at regional scale. However, the determinants that driving the biogeography of phytoplankton communities in the coastal area of northern Zhejiang still remained unclear. We surveyed phytoplankton community compositions in water columns associated with environmental and spatial influences across five subzones that geographically covering this region over four seasons. Diatoms and dinoflagellates were recorded as the main dominant groups and Coscinodiscus oculs-iridis, Coscinodiscus jonesianus, and Skeletonema costatum, were identified as the major abundant species existing in all seasons.Spatially structured environmental conditions, rather than pure spatial or environmental factors, substantially shaped the biogeography of phytoplankton community, with the former mainly comprised of water temperature,dissolved oxygen, phosphate, pH, and salinity, and the latter referring to a non-negligible factor. This study was the first integrated research that combining environmental filtering with spatial factors in structuring phytoplankton communities at a complete tempo-spatial scale. Our results may facilitate to the further study of harmful algal blooms early-warning in this region.展开更多
Limbita 1 is a hilltop settlement in the rural town of khorira, the district of Dubreka. It is a land of the locality commonly called “limbita quarry”, and widely converted by bricks manufacturers of Dubreka distric...Limbita 1 is a hilltop settlement in the rural town of khorira, the district of Dubreka. It is a land of the locality commonly called “limbita quarry”, and widely converted by bricks manufacturers of Dubreka district and those of conakry area. However, no information about the characteristics of this land’s soil is yet available. The soil’s characteristics are then determined through the series of tests (granulometry, Atterberg limits, modified proctor, CBR, shear, odometric compressibility). These tests are carried out with samples derived from the site of Limbita within the area of Limbita 1. This work shows very consistent results that made it possible to deduce the very swelling nature of the soil.展开更多
The environmental impact of coastal sand mining activities in Hai Phong city was assessed using ten proposed sustainable criteria for socio-economic development,and ecological and environmental protection.These ten cr...The environmental impact of coastal sand mining activities in Hai Phong city was assessed using ten proposed sustainable criteria for socio-economic development,and ecological and environmental protection.These ten criteria were developed by the analysis of the Dynamics-Pressure-State-Impact-Response(DPSIR)framework,including one driver and pressure criterion(D and P),seven status and impact criteria(S and I),and two response criteria(R).Each criterion is quantified according to five specific evaluation criteria corresponding to the evaluation score from 1 to 5.The results of the ten criterion application for environmental impact assessment of coastal mining Hai Phong by weighting show that the areas with economic activities,benthic biodiversity,and coastal ecosystems are most negatively impacted(score 4/5 and 3.5/5).Other subjects suffer low to moderate impacts(score 1/5 to 3/5).The environmental impact of sand mining(2015-2020)is generally moderate(score ranging from 2/5 to 3/5).The set of adjusted criteria can be applied to similar activities in coastal provinces and cities in Vietnam.展开更多
To investigate the values of 10-m drag coefficient(CD ) in different coastal areas under the influence of tropical cyclones, the present study used the observational data from four towers in different coastal areas of...To investigate the values of 10-m drag coefficient(CD ) in different coastal areas under the influence of tropical cyclones, the present study used the observational data from four towers in different coastal areas of the South China Sea(SCS) during six tropical cyclone(TC) passages, and employed the eddy covariance method and the flux profile method.The analysis of footprint showed that the fluxes at Zhizai Island(ZZI), Sanjiao Island(SJI) and Donghai Island(DHI)were influenced basically by the ocean, and the flux at Shangyang Town(SYT) was influenced mainly by the land. The results showed that the dependence relationships of CD on 10-m wind speed(U10) in four different coastal areas under the influence of TCs were different. CD at ZZI and SJI initially increased and then decreased as U10 increased, similar to the pattern over the ocean. CD at ZZI and SJI represented the values over shallow water with seawater depths of ~7 m and ~2 m, respectively. Moreover, the critical wind speed at which CD peaked gradually decreased as the seawater depth became shallower in the coastal areas. CD at DHI and SYT decreased monotonously as U10 increased, similar to the pattern over the land. CD at DHI represented the value over the transition zone from shallow water to coastal land, and CD at SYT represented the value over the coastal land. Meanwhile, the eddy covariance method and the flux profile method were compared at ZZI and SYT during TC passages. It was found that their CD values obtained by the two methods were close. Finally, the parameterizations of observed u*and CD as a function of U10 over four different coastal areas were given under the influence of high winds. These parameterizations of observed CD may be used in high-resolution numerical models for landfalling TC forecast.展开更多
Air pollution has become a critical issue in urban areas,so a broad understanding of its spatiotemporal characteristics is important to develop public policies.This study analyzes the spatiotemporal variation of atmos...Air pollution has become a critical issue in urban areas,so a broad understanding of its spatiotemporal characteristics is important to develop public policies.This study analyzes the spatiotemporal variation of atmospheric particulate matter(PM_(10) and PM_(2.5))and ozone(O_(3))in Barranquilla,Colombia from March 2018 to June 2019 in three monitoring stations.The average concentrations observed for the Móvil,Policía,and Tres Avemarías stations,respectively,for PM_(10):46.4,51.4,and 39.7μg/m^(3);for PM_(2.5):16.1,18.1,and 15.1μg/m^(3) and for O_(3):35.0,26.6,and 33.6μg/m^(3).The results indicated spatial and temporal variations between the stations and the pollutants evaluated.The highest PM concentrations were observed in the southern part of the city,while for ozone,higher concentrations were observed in the north.These variations are mainly associated with the influence of local sources in the environment of each site evaluated as well as the meteorological conditions and transport patterns of the study area.This study also verified the existence of differences in the concentrations of the studied pollutants between the dry and rainy seasons and the contribution of local sources as biomass burnings from the Isla Salamanca Natural Park and long-range transport of dust particles from the Sahara Desert.This study provides a scientific baseline for understanding air quality in the city,which enables policy makers to adopt efficient measures that jointly prevent and control pollution.展开更多
A 10-year(2003–2012)hindcast was conducted to study the wave field in the Zhe-Min coastal area(Key Area OE-W2)located off Zhejiang and Fujian provinces of China.Forced by the wind field from a weather research and fo...A 10-year(2003–2012)hindcast was conducted to study the wave field in the Zhe-Min coastal area(Key Area OE-W2)located off Zhejiang and Fujian provinces of China.Forced by the wind field from a weather research and forecasting model(WRF),high-resolution wave modelling using the SWAN was carried out in the study area.The simulated wave fields show a good agreement with observations.Using the simulation results,we conducted statistical analysis of wave power density in terms of spatial distribution and temporal variation.The effective duration of wave energy in the sea area was discussed,and the stability of wave energy was evaluated using the coefficient of variation of wave power density.Results indicate that the wave energy resource in the study area was about 4.11×10^(6) kW.The distribution of wave energy tends to increase from the north(off Zhejiang coast)to the south(off Fujian coast),and from near-shore area to the open sea.The sea areas with wave power density greater than 2 kW/m are mostly distributed seaward of the 10-m isobath,and the contours of the wave power density are almost parallel to the shoreline.The sea areas around the islands that are far from the mainland are rich in wave energy,usually more than 6 kW/m,and therefore are of obvious advantages in planning wave energy development and utilization.The effective duration of wave energy in the offshore area shows an increasing trend from north(off Zhejiang coast)to south(off Fujian coast),with values of∼3500 h in the north and∼4450 h in the south.The coefficient of variation of wave energy in this region is mostly in the range of 1.5–3.0,and gradually decreases from the north to the south,suggesting that the wave energy in the south is more stable than that in the north.展开更多
Watamu Mida creek coastal areas, mainly the shoreline, the mangroves and the general environment have been changing due to the impact of land use change, shoreline erosion, human population pressure and the expansion ...Watamu Mida creek coastal areas, mainly the shoreline, the mangroves and the general environment have been changing due to the impact of land use change, shoreline erosion, human population pressure and the expansion of tourism sector. This research assesses the impact of land use change on mangrove dynamics and shoreline erosion as well as the main driving factors that cause these changes in Watamu Midacreek. This study uses old aerial photographs (1969 and 1989), current high resolution satellite images World view (2010) and ground truthing in combination with information from the local community to analyze the impact of change in land use from 1969-2010. Land use and cover types were visually interpreted, digitized and delineated using aerial photographs of 1969, 1989 and 2010 satellite images in ArcGIS.9.3.1 and ERDAS IMAGINE 2014 software. The results of the land use change between 1969 and 1989 showed a decline of scrub land, miscellaneous coastal vegetation, coastal bush, thicket with trees and mangroves, whereas new types of land use which emerged during this period were town and barren land. The greatest land use change rate observed between 1969 and 1989 was in miscellaneous coastal vegetation at 2.5%, while coastal bush experienced a significant negative change rate of 6.5%. The main land use changes observed between 1989 and 2010 were increasing coastal bush, an expansion of town and urban areas, hotels and private holiday houses. Encroachments into the mangrove forest have been observed both by local people and foreign private holiday house owners. The change in land use had an impact on shoreline changes as well. Areas mainly covered by old trees, and coastal bushes which protected the shoreline from erosion currently have been converted into very big hotels and several private holiday house complexes. The main drivers of land use change were human population growth and policy (through weakness of law enforcement). Policies and regulations which are not currently implemented need to be updated based on the current pressure-state situation, and there should be strong law enforcement and strict regulation to control any unplanned developments along the coast and in the neighboring hinterland.展开更多
Blooms of some pico/nanophytoplankton have occurred frequently along the Qinhuangdao coast since 2009, and it is necessary to identify the critical environmental factors inducing them. In this study, variations in the...Blooms of some pico/nanophytoplankton have occurred frequently along the Qinhuangdao coast since 2009, and it is necessary to identify the critical environmental factors inducing them. In this study, variations in the physical and nutrient characteristics of the seawater were analyzed following the development of local blooms in 2013. The local environmental characteristics were also compared with those of the Changjiang River estuary, China, and the Long Island estuaries in the USA, which are also prone to blooms of special algal species. In Qinhuangdao the local water temperature varied seasonally and rose above 15°C in 2013 early summer, coincident with the water discoloration. The salinity was more than 28 with a variation range of <3 throughout the year. Our results suggest that the physical conditions of the Qinhuangdao coastal area were suitable for the explosive proliferation of certain pico/nanophytoplankton, e.g. Aureococcus anophageff erens. The water supporting the bloom was not in a condition of serious eutrophication, but there were relatively high concentrations of reduced nitrogen(especially ammonium), which acted as an important nitrogen source for the pico/nanophytoplankton bloom. There was also a large gap between total nitrogen(TN) and dissolved inorganic nitrogen(DIN). Although the phosphate concentration was relatively low, there was no evidence of phosphorus limitation to the growth of pico/nanophytoplankton during bloom events.展开更多
Populations and metropolitan centers are accumulated in coastal areas around the world.In view of the fact that they are geographically adjacent to coasts and intense anthropogenic activities,increasing global offshor...Populations and metropolitan centers are accumulated in coastal areas around the world.In view of the fact that they are geographically adjacent to coasts and intense anthropogenic activities,increasing global offshore pollution has been an important worldwide concern over the past several decades and has become a very serious problem that needs to be addressed urgently.Due to offshore pollution,various geological disasters occur in high frequency,including intensified erosion and salinization of coastal soils,frequent geological collapses and landslides and increasing seismic activities.Moreover,offshore pollution shows increasingly serious impacts on the topography and geomorphology of offshore and coastal areas,including coastal degradation,retreating coastlines and estuary delta erosion.Offshore sedimentation processes are strongly influenced by the pH changes of terrestrial discharges,and sedimentary dynamics have become extremely acute and complex due to offshore pollution.The seabed topography and hydrodynamic environment determine the fate and transport of pollutants entering offshore regions.Coastal estuaries,port basins and lagoons that have relatively moderate ocean currents and winds are more likely to accumulate pollutants.Offshore regions and undersea canyons can be used as conduits for transporting pollutants from the continent to the seabed.It is particularly noteworthy that the spatial/temporal distribution of species,community structures,and ecological functions in offshore areas have undergone unprecedented changes in recent decades.Due to increasing offshore pollution,the stable succession and development trend of marine ecosystems has been broken.It is thus important to identify and regulate the quantity,composition and transportation of pollutants in offshore regions and their behavior in marine ecosystems.In particular,crucial actions for stabilizing marine ecosystems,including increasing species and biodiversity,should be implemented to enhance their anti-interference capabilities.This review provides an overview of the current situation of offshore pollution,as well as major trends of pollutant fate and transportation from continent to marine ecosystems,transformation of pollutants in sediments,and their bioaccumulation and diffusion.This study retrospectively reviews the long-term geological evolution of offshore pollution from the perspective of marine geology,and analyses their long-term potential impacts on marine ecosystems.Due to ecological risks associated with pollutants released from offshore sediments,more research on the influence of global offshore pollution based on marine geology is undoubtedly needed.展开更多
The growth of tidal flats off Zhejiang coasts in southwestern China has provided substantial areas for local agriculture and construction activities.To evaluate modern and future development of tidal flats in the regi...The growth of tidal flats off Zhejiang coasts in southwestern China has provided substantial areas for local agriculture and construction activities.To evaluate modern and future development of tidal flats in the region,a good understanding of sediment sources is necessary.Previous research has concluded that the Changjiang(Yangtze)River is the dominant supplier of sediments to this part of the southeast Chinese coast,despite the fact that sediment delivery from this source has been decreased markedly in the past two decades.In this study,we investigated the sources of tidal flat sediments,and the magnetic and geochemical properties of recent tidal flat sediments along the Zhejiang coast were compared with those discharged from rivers.Magnetic and geochemical properties of the tidal flat samples reveal statistically distinct sediment provenance groups.The magnetic and geochemical scatter plots show that the suspended sediment samples are naturally divided into two different groups,one including the Changjiang River and Qiantang River material,and the other including the Jiaojiang,Oujiang,and Feiyun Rivers that located in the central and southern parts of the study areas.At last,a binary source of tidal flat sediments along the Zhejiang coast was determined,with the substantial majority originating from local rivers,while a much smaller proportion emanates from the Changjiang River to the north.We conclude that the sediment contribution of the Changjiang River to tidal flat development in the region has been markedly overestimated,with important implications for management.展开更多
Following previous studies of the rainfall forecast in Shenzhen owing to landfalling tropical cyclones(TCs),a nonparametric statistical scheme based on the classification of the landfalling TCs is applied to analyze a...Following previous studies of the rainfall forecast in Shenzhen owing to landfalling tropical cyclones(TCs),a nonparametric statistical scheme based on the classification of the landfalling TCs is applied to analyze and forecast the rainfall induced by landfalling TCs in the coastal area of Guangdong province,China.All the TCs landfalling with the distance less than 700 kilometers to the 8 coastal stations in Guangdong province during 1950—2013 are categorized according to their landfalling position and intensity.The daily rainfall records of all the 8 meteorological stations are obtained and analyzed.The maximum daily rainfall and the maximum 3 days’accumulated rainfall at the 8 coastal stations induced by each category of TCs during the TC landfall period(a couple of days before and after TC landfalling time)from 1950 to 2013 are computed by the percentile estimation and illustrated by boxplots.These boxplots can be used to estimate the rainfall induced by landfalling TC of the same category in the future.The statistical boxplot scheme is further coupled with the model outputs from the European Centre for Medium-Range Weather Forecasts(ECMWF)to predict the rainfall induced by landfalling TCs along the coastal area.The TCs landfalling in south China from 2014 to 2017 and the corresponding rainfall at the 8 stations area are used to evaluate the performance of these boxplots and coupled boxplots schemes.Results show that the statistical boxplots scheme and coupled boxplots scheme can perform better than ECMWF model in the operational rainfall forecast along the coastal area in south China.展开更多
This study surveyed the levels of boundary layer surface turbulence across a West African climate region. Five years (2011-2015) temperature and wind speed data at synoptic hours 0000 Hr, 0600 Hr, 1200 Hr and 1800 Hr ...This study surveyed the levels of boundary layer surface turbulence across a West African climate region. Five years (2011-2015) temperature and wind speed data at synoptic hours 0000 Hr, 0600 Hr, 1200 Hr and 1800 Hr within 0.125<span style="white-space:nowrap;">°</span> grid resolution was sourced from Era-Interim Reanalysis platform at 1000 mbar pressure level. Using the Richardson (Ri) number technique, results showed that mechanical turbulence of Ri range 0.04 - 0.57 dominates across the surface layer for study locations of Port Harcourt, Enugu, Jos, Kano and Maiduguri than thermal turbulence. However, the least turbulent area was the coastal zone of surveyed region. Results also indicated that the vertical height (L) at which thermal turbulence replaces mechanical turbulence across study locations ranged from 20 - 250 m with lowest replacement levels (20 - 50 m) occurring mainly in the coastal area of Port Harcourt during periods of dawn. The most turbulent periods in the southern coastal location of study region were during key rainy periods from June-August while that for the rest far northern inland areas occur during the dry season/early rainy periods i.e. November-May. The implication of the lower surface turbulence/replacement level within coastal domains most especially during periods of dawn is that emission releases near surface layer will be dispersed after initial rise due to buoyancy at horizontal levels thereby increasing ground level pollutants concentration across sensitive receptors that are close to emission source. At heights of thermal turbulence replacement, emission releases will be transported vertically and then dispersed further away from emission sources, thus impacting sensitive receptors at farther distances. This is the atmospheric boundary layer dynamics that makes ground level pollution worse in the coastal city of Port Harcourt in recent times during periods of dawn. Efforts must be made by concerned Stakeholders towards ensuring that emissions are reduced during the periods of dawn within and around coastal environments.展开更多
Nitrous acid(HONO)is an important source of hydrogen oxides(HOx),which affects air quality,the atmospheric oxidation capacity,and human health.Here,we present ambient measurements of the HONO concentrations in Zhuhai,...Nitrous acid(HONO)is an important source of hydrogen oxides(HOx),which affects air quality,the atmospheric oxidation capacity,and human health.Here,we present ambient measurements of the HONO concentrations in Zhuhai,a coastal city in Southern China,from February 7 to March 15,2021.The campaign was classified into two periods during(P1)and after(P2)the Spring Festival holidays.The average HONO mixing ratio during P2(1.19±0.85 ppbv)was much higher than that during P1(0.24±0.18 ppbv),likely due to the contribution of homogeneous HONO formation.During nighttime,the heterogeneous conversion rate during P2(0.0089/hr)was considerably higher than that during P1(0.0057/hr),suggesting a higher heterogeneous NO_(2) conversion potential.However,the heterogeneous NO_(2) conversion was the dominant way during P1 with a high percentage of 88%,while comparable ratios of heterogeneous and homogeneous formation were found(54%vs.46%)during P2,indicating that the homogeneous formation was also important during P2.During daytime,homogeneous reaction was the major known pathway,with a contribution of 16%during P1 and 27%during P2,leaving large unknown HONO sources which reasonably correlated with the photo-enhanced NO_(2) conversion.Two case scenarios were additionally explored,showing that there might be a primary emission source during one scenario(February 17-18)and vehicle emissions might be the major unknown HONO source for another scenario(March 3–5).The results suggest that large unknown daytime sources still exist which need more future ambient and laboratory studies.展开更多
Winter chilling is critical for most temperate fruits and perennial plants during the winter season. Most fruit and nut trees require a prolonged period of chilling to break their dormant stage and bloom when spring a...Winter chilling is critical for most temperate fruits and perennial plants during the winter season. Most fruit and nut trees require a prolonged period of chilling to break their dormant stage and bloom when spring arrives. This research’s primary objective was to calculate the chill hour’s accumulation in each county in South Carolina based on the historical hourly air temperature data for the last ten years (2010-2020). The chilling hours model used to calculate the daily chill hours was based on the number of hours when the air temperature was between 32<span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#FFFFFF;">°</span>F to 45<span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#FFFFFF;">°</span>F (0 to 7.2<span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#FFFFFF;">°</span>C). The total chill hours for each county were then determined by accumulating the daily chill hours <span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">from</span></span></span><span><span><span style="font-family:" color:red;"=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">October to June. Our results showed that among the different counties in South Carolina, on average Laurens County had the most prolonged chill hours (1419 hrs). The chill hours were higher between November to March, and counties near the coastal regions had fewer chill hours than the counties in the inland areas. For example, Beaufort, Charleston, Berkeley, Horry, and Dorchester counties that are located near the coastal region had fewer chill hours. In contrast, counties located in the inland areas like Laurens, Chester, Lancaster, and York recorded the most prolonged chill hours. Our results suggest that selecting high chilling requirement crops for the inland areas and low chilling requirement crops for coastal areas would be appropriate. Farmers in South Carolina can use this information to plan their crop selection and management.</span></span></span>展开更多
文摘Pollution in the coastal areas negatively affects biochemical indicators of seawater, human health and marine organisms. Hai Phong is a coastal city of Vietnam with the development of socio-economic activities, representing through an increasing number of industrial zones. This study is to evaluate the pollution of large industrial zones in Hai Phong city using numerical models. The numerical simulation (MIKE 21 SW, FM, ECO Lab) models were applied to simulate the wave propagation, hydraulic regime, water quality in coastal Hai Phong area. The MIKE 21 ECO Lab model was used to evaluate sources of waste from the large coastal industrial zones to some aquaculture zones. The calibration and validation results of wave propagation and the hydrodynamic models were resonably good, with Nash coefficient ranging from 0.65 to 0.90 and a percent bias (PBIAS) from 5.6% to 9.4%. The simulation results of water quality and concentration of pollutants (DO, BOD<sub>5</sub>, COD, TSS, Fe, and Coliform) in 2023 at the aquaculture locations show that the BOD<sub>5</sub>, COD, and TSS concentrations were higher than the allowable limits stated in the national technical regulation on surface water quality (QCVN 08:2023/BTNMT) and lower than the allowable limits stated in the national technical regulation on marine water quality (QCVN 10:2023/BTNMT). The outcomes of this study will provide more information to support managers to come up with a better socio-economic development plan for Hai Phong city to achieve sustainable development.
文摘Biomass and carbon stock in a forested areas are now prime important indicators of forest management and climate change mitigation measures. But the accurate estimation of biomass and carbon in trees of forests is now a challenging issue. In most cases, pantropical and regional biomass models are used frequently to estimate biomass and carbon stock in trees, but these estimation</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">s</span></span></span><span><span><span style="font-family:""><span style="font-family:Verdana;"> have some uncertainty compared to the species-specific allometric biomass model. </span><i><span style="font-family:Verdana;">Acacia</span></i><span> <i><span style="font-family:Verdana;">nilotica</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">Casuarina</span></i> <i><span style="font-family:Verdana;">equisetifolia</span></i></span><span style="font-family:Verdana;"> and </span><i><span style="font-family:Verdana;">Melia</span></i><span style="font-family:Verdana;"> <i>azedarach</i> </span><span style="font-family:Verdana;">have been planted in different areas of Bangladesh considering the species-specific site requirements. While </span><i><span style="font-family:Verdana;">Barringtonia</span></i><span style="font-family:Verdana;"> <i>acutangula</i></span><span style="font-family:Verdana;"> and </span><i><span style="font-family:Verdana;">Pongamia</span></i><span style="font-family:Verdana;"> <i>pinnata</i> </span><span style="font-family:Verdana;">are the dominant tree species of the freshwater swamp forest of Bangladesh. This study was aimed to develop species-specific allometric biomass models for estimating stem and above ground biomass (TAGB) of these species using the non-destructive method and to compare the efficiency of the derived biomass models with the frequently used regional and pantropical biomass models. Four Ln-based models with diameter at breast height (DBH) and total height (H) were tested to derive the best fit allometric model. Among the tested models, Ln (biomass) = a + b Ln (D) + c Ln (H) was the best-fit model for </span><i><span style="font-family:Verdana;">A</span></i><span><span style="font-family:Verdana;">. </span><i><span style="font-family:Verdana;">nilotica</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">M</span></i><span style="font-family:Verdana;">. </span><i><span style="font-family:Verdana;">azedarach</span></i><span style="font-family:Verdana;">, </span><i><span style="font-family:Verdana;">B</span></i><span style="font-family:Verdana;">. </span><i><span style="font-family:Verdana;">acutangula</span></i> </span><span style="font-family:Verdana;">and</span><span> <i><span style="font-family:Verdana;">P</span></i><span style="font-family:Verdana;">. </span><i><span style="font-family:Verdana;">pinnata</span></i> </span><span style="font-family:Verdana;">and Ln (biomass) = a + b Ln (D</span><sup><span style="font-family:Verdana;">2</span></sup><span style="font-family:Verdana;">H) was best-fit for </span><i><span style="font-family:Verdana;">C</span></i><span><span style="font-family:Verdana;">. </span><i><span style="font-family:Verdana;">equisetifolia</span></i><span style="font-family:Verdana;">. </span></span><span style="font-family:Verdana;">Finally</span></span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">,</span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;"> the derived best-fit species-specific TAGB models have shown superiority over the other frequently used pantropical and regional biomass models in relation to model efficiency and model prediction error.
基金Under the auspices of the National Natural Science Foundation of China(No.42076222)。
文摘Marine science technology innovation provides power and guarantees for marine eco-civilization construction,which provides direction and material support for marine science technology innovation.Therefore,the coordinated development of the two is of great significance to the marine economy sustainable development in China’s coastal areas.On the basis of clarifying the connotations of marine science technology innovation and marine eco-civilization in China’s coastal areas from 2006 to 2019,the mechanism for their coordinated development was analysed.A comprehensive indicator system based on the connotation of the two was constructed,and the coordinated development relationship was empirically tested using the coupled coordination model and the panel vector autoregressive(PVAR)model.The results show that:1)the level of China’s coastal marine science technology innovation continues to improve,gradually forming the core of the development of marine science technology innovation in the north,east and south of Shandong,Shanghai and Guangdong;the level of marine eco-civilization development fluctuating upward trend,showing obvious spatial differentiation characteristics.2)The degree of coordination of marine science technology innovation and marine eco-civilization is growing over time.There is no causal relationship between marine science technology innovation and marine eco-civilization in the northern marine economic circle,but there is a two-way causal relationship between the two in the eastern and southern marine economic circles.3)Marine eco-civilization shows a significant positive and continuous impact on marine science technology innovation,and marine science technology innovation shows a long-term,continuous,fluctuating,and lagging impact on marine eco-civilization.The overall role of marine eco-civilization on marine science technology innovation is dominant,and there are significant differences in the impact effects of the two major marine economic circles.
文摘The Coastal Zone Management Act was finally promulgated in 2015,while Ministry of the Interior was asked to draft a coastal management act in 1991 by Executive Yuan.It was until the government’s lifting of martial law in 1987,vigorous activities started prevailing on coastal areas.And relevant legal documents were on sea reclamation for development in the 1980’s by Council of Agriculture.The approval of“Taiwan Coastal Area Natural Environment Protection Plan”showed an era of environmental protection in 1980s.However,it was surely not market driven,similar to land development,but some efforts by the administration systems.Through all the years,the efforts were put on drafting plans and these efforts were not quite sounding.The coastal disasters and further climate change caught the attention of relevant NGOs,scholars,politicians,and the society.At the critical juncture the government was made to react to outside demands.And then the Coastal Zone Management Act was passed by Legislative Yuan,establishing an integrated coastal management system in Taiwan.As such,it is proposed to look into this long process of the attempt with the concept of institutional change in order to understand this coastal environmental preservation and protection issue in a broader scope.
基金Ecological Restoration Cost Evaluation in Archipelago Ecosystems:A Case Study in Putuo,Zhoushan Archipelago,East China Sea.
文摘Understanding the relative roles of local environmental effects and spatial effects on phytoplankton community is of essential importance to study the biogeography of them at regional scale. However, the determinants that driving the biogeography of phytoplankton communities in the coastal area of northern Zhejiang still remained unclear. We surveyed phytoplankton community compositions in water columns associated with environmental and spatial influences across five subzones that geographically covering this region over four seasons. Diatoms and dinoflagellates were recorded as the main dominant groups and Coscinodiscus oculs-iridis, Coscinodiscus jonesianus, and Skeletonema costatum, were identified as the major abundant species existing in all seasons.Spatially structured environmental conditions, rather than pure spatial or environmental factors, substantially shaped the biogeography of phytoplankton community, with the former mainly comprised of water temperature,dissolved oxygen, phosphate, pH, and salinity, and the latter referring to a non-negligible factor. This study was the first integrated research that combining environmental filtering with spatial factors in structuring phytoplankton communities at a complete tempo-spatial scale. Our results may facilitate to the further study of harmful algal blooms early-warning in this region.
文摘Limbita 1 is a hilltop settlement in the rural town of khorira, the district of Dubreka. It is a land of the locality commonly called “limbita quarry”, and widely converted by bricks manufacturers of Dubreka district and those of conakry area. However, no information about the characteristics of this land’s soil is yet available. The soil’s characteristics are then determined through the series of tests (granulometry, Atterberg limits, modified proctor, CBR, shear, odometric compressibility). These tests are carried out with samples derived from the site of Limbita within the area of Limbita 1. This work shows very consistent results that made it possible to deduce the very swelling nature of the soil.
基金support of the VAST project,code VAST05.06/22-23.
文摘The environmental impact of coastal sand mining activities in Hai Phong city was assessed using ten proposed sustainable criteria for socio-economic development,and ecological and environmental protection.These ten criteria were developed by the analysis of the Dynamics-Pressure-State-Impact-Response(DPSIR)framework,including one driver and pressure criterion(D and P),seven status and impact criteria(S and I),and two response criteria(R).Each criterion is quantified according to five specific evaluation criteria corresponding to the evaluation score from 1 to 5.The results of the ten criterion application for environmental impact assessment of coastal mining Hai Phong by weighting show that the areas with economic activities,benthic biodiversity,and coastal ecosystems are most negatively impacted(score 4/5 and 3.5/5).Other subjects suffer low to moderate impacts(score 1/5 to 3/5).The environmental impact of sand mining(2015-2020)is generally moderate(score ranging from 2/5 to 3/5).The set of adjusted criteria can be applied to similar activities in coastal provinces and cities in Vietnam.
基金Project of Science and Technology Department of Guangdong Province(2019B111101002)National Natural Science Foundation of China(41675019,41675021)。
文摘To investigate the values of 10-m drag coefficient(CD ) in different coastal areas under the influence of tropical cyclones, the present study used the observational data from four towers in different coastal areas of the South China Sea(SCS) during six tropical cyclone(TC) passages, and employed the eddy covariance method and the flux profile method.The analysis of footprint showed that the fluxes at Zhizai Island(ZZI), Sanjiao Island(SJI) and Donghai Island(DHI)were influenced basically by the ocean, and the flux at Shangyang Town(SYT) was influenced mainly by the land. The results showed that the dependence relationships of CD on 10-m wind speed(U10) in four different coastal areas under the influence of TCs were different. CD at ZZI and SJI initially increased and then decreased as U10 increased, similar to the pattern over the ocean. CD at ZZI and SJI represented the values over shallow water with seawater depths of ~7 m and ~2 m, respectively. Moreover, the critical wind speed at which CD peaked gradually decreased as the seawater depth became shallower in the coastal areas. CD at DHI and SYT decreased monotonously as U10 increased, similar to the pattern over the land. CD at DHI represented the value over the transition zone from shallow water to coastal land, and CD at SYT represented the value over the coastal land. Meanwhile, the eddy covariance method and the flux profile method were compared at ZZI and SYT during TC passages. It was found that their CD values obtained by the two methods were close. Finally, the parameterizations of observed u*and CD as a function of U10 over four different coastal areas were given under the influence of high winds. These parameterizations of observed CD may be used in high-resolution numerical models for landfalling TC forecast.
文摘Air pollution has become a critical issue in urban areas,so a broad understanding of its spatiotemporal characteristics is important to develop public policies.This study analyzes the spatiotemporal variation of atmospheric particulate matter(PM_(10) and PM_(2.5))and ozone(O_(3))in Barranquilla,Colombia from March 2018 to June 2019 in three monitoring stations.The average concentrations observed for the Móvil,Policía,and Tres Avemarías stations,respectively,for PM_(10):46.4,51.4,and 39.7μg/m^(3);for PM_(2.5):16.1,18.1,and 15.1μg/m^(3) and for O_(3):35.0,26.6,and 33.6μg/m^(3).The results indicated spatial and temporal variations between the stations and the pollutants evaluated.The highest PM concentrations were observed in the southern part of the city,while for ozone,higher concentrations were observed in the north.These variations are mainly associated with the influence of local sources in the environment of each site evaluated as well as the meteorological conditions and transport patterns of the study area.This study also verified the existence of differences in the concentrations of the studied pollutants between the dry and rainy seasons and the contribution of local sources as biomass burnings from the Isla Salamanca Natural Park and long-range transport of dust particles from the Sahara Desert.This study provides a scientific baseline for understanding air quality in the city,which enables policy makers to adopt efficient measures that jointly prevent and control pollution.
基金The National Key R&D Program of China under contract No.2018YFB1501901the Zhejiang Provincial Natural Science Foundation of China under contract No.LY21D060003the Project of State Key Laboratory of Satellite Ocean Environment Dynamics,Second Institute of Oceanography,Ministry of Natural Resources,under contract Nos SOEDZZ2103 and SOEDZZ2003.
文摘A 10-year(2003–2012)hindcast was conducted to study the wave field in the Zhe-Min coastal area(Key Area OE-W2)located off Zhejiang and Fujian provinces of China.Forced by the wind field from a weather research and forecasting model(WRF),high-resolution wave modelling using the SWAN was carried out in the study area.The simulated wave fields show a good agreement with observations.Using the simulation results,we conducted statistical analysis of wave power density in terms of spatial distribution and temporal variation.The effective duration of wave energy in the sea area was discussed,and the stability of wave energy was evaluated using the coefficient of variation of wave power density.Results indicate that the wave energy resource in the study area was about 4.11×10^(6) kW.The distribution of wave energy tends to increase from the north(off Zhejiang coast)to the south(off Fujian coast),and from near-shore area to the open sea.The sea areas with wave power density greater than 2 kW/m are mostly distributed seaward of the 10-m isobath,and the contours of the wave power density are almost parallel to the shoreline.The sea areas around the islands that are far from the mainland are rich in wave energy,usually more than 6 kW/m,and therefore are of obvious advantages in planning wave energy development and utilization.The effective duration of wave energy in the offshore area shows an increasing trend from north(off Zhejiang coast)to south(off Fujian coast),with values of∼3500 h in the north and∼4450 h in the south.The coefficient of variation of wave energy in this region is mostly in the range of 1.5–3.0,and gradually decreases from the north to the south,suggesting that the wave energy in the south is more stable than that in the north.
文摘Watamu Mida creek coastal areas, mainly the shoreline, the mangroves and the general environment have been changing due to the impact of land use change, shoreline erosion, human population pressure and the expansion of tourism sector. This research assesses the impact of land use change on mangrove dynamics and shoreline erosion as well as the main driving factors that cause these changes in Watamu Midacreek. This study uses old aerial photographs (1969 and 1989), current high resolution satellite images World view (2010) and ground truthing in combination with information from the local community to analyze the impact of change in land use from 1969-2010. Land use and cover types were visually interpreted, digitized and delineated using aerial photographs of 1969, 1989 and 2010 satellite images in ArcGIS.9.3.1 and ERDAS IMAGINE 2014 software. The results of the land use change between 1969 and 1989 showed a decline of scrub land, miscellaneous coastal vegetation, coastal bush, thicket with trees and mangroves, whereas new types of land use which emerged during this period were town and barren land. The greatest land use change rate observed between 1969 and 1989 was in miscellaneous coastal vegetation at 2.5%, while coastal bush experienced a significant negative change rate of 6.5%. The main land use changes observed between 1989 and 2010 were increasing coastal bush, an expansion of town and urban areas, hotels and private holiday houses. Encroachments into the mangrove forest have been observed both by local people and foreign private holiday house owners. The change in land use had an impact on shoreline changes as well. Areas mainly covered by old trees, and coastal bushes which protected the shoreline from erosion currently have been converted into very big hotels and several private holiday house complexes. The main drivers of land use change were human population growth and policy (through weakness of law enforcement). Policies and regulations which are not currently implemented need to be updated based on the current pressure-state situation, and there should be strong law enforcement and strict regulation to control any unplanned developments along the coast and in the neighboring hinterland.
基金Supported by the National Natural Science Foundation of China(No.41576119)the Strategic Priority Research Program of the Chinese Academy of Sciences(No.XDA11020302)the Public Science and Technology Research Funds Projects of Ocean(No.201305003-3)
文摘Blooms of some pico/nanophytoplankton have occurred frequently along the Qinhuangdao coast since 2009, and it is necessary to identify the critical environmental factors inducing them. In this study, variations in the physical and nutrient characteristics of the seawater were analyzed following the development of local blooms in 2013. The local environmental characteristics were also compared with those of the Changjiang River estuary, China, and the Long Island estuaries in the USA, which are also prone to blooms of special algal species. In Qinhuangdao the local water temperature varied seasonally and rose above 15°C in 2013 early summer, coincident with the water discoloration. The salinity was more than 28 with a variation range of <3 throughout the year. Our results suggest that the physical conditions of the Qinhuangdao coastal area were suitable for the explosive proliferation of certain pico/nanophytoplankton, e.g. Aureococcus anophageff erens. The water supporting the bloom was not in a condition of serious eutrophication, but there were relatively high concentrations of reduced nitrogen(especially ammonium), which acted as an important nitrogen source for the pico/nanophytoplankton bloom. There was also a large gap between total nitrogen(TN) and dissolved inorganic nitrogen(DIN). Although the phosphate concentration was relatively low, there was no evidence of phosphorus limitation to the growth of pico/nanophytoplankton during bloom events.
基金financially supported by the National Natural Science Foundation of China as a Shandong joint key project(Grant No.U1906222)the Ministry of Environmental Science and Technology,People’s Republic of China as a key R&D project(Grant No.2019YFC1804104)the Ministry of Education,People’s Republic of China as a 111 program(Grant No.T2017002)。
文摘Populations and metropolitan centers are accumulated in coastal areas around the world.In view of the fact that they are geographically adjacent to coasts and intense anthropogenic activities,increasing global offshore pollution has been an important worldwide concern over the past several decades and has become a very serious problem that needs to be addressed urgently.Due to offshore pollution,various geological disasters occur in high frequency,including intensified erosion and salinization of coastal soils,frequent geological collapses and landslides and increasing seismic activities.Moreover,offshore pollution shows increasingly serious impacts on the topography and geomorphology of offshore and coastal areas,including coastal degradation,retreating coastlines and estuary delta erosion.Offshore sedimentation processes are strongly influenced by the pH changes of terrestrial discharges,and sedimentary dynamics have become extremely acute and complex due to offshore pollution.The seabed topography and hydrodynamic environment determine the fate and transport of pollutants entering offshore regions.Coastal estuaries,port basins and lagoons that have relatively moderate ocean currents and winds are more likely to accumulate pollutants.Offshore regions and undersea canyons can be used as conduits for transporting pollutants from the continent to the seabed.It is particularly noteworthy that the spatial/temporal distribution of species,community structures,and ecological functions in offshore areas have undergone unprecedented changes in recent decades.Due to increasing offshore pollution,the stable succession and development trend of marine ecosystems has been broken.It is thus important to identify and regulate the quantity,composition and transportation of pollutants in offshore regions and their behavior in marine ecosystems.In particular,crucial actions for stabilizing marine ecosystems,including increasing species and biodiversity,should be implemented to enhance their anti-interference capabilities.This review provides an overview of the current situation of offshore pollution,as well as major trends of pollutant fate and transportation from continent to marine ecosystems,transformation of pollutants in sediments,and their bioaccumulation and diffusion.This study retrospectively reviews the long-term geological evolution of offshore pollution from the perspective of marine geology,and analyses their long-term potential impacts on marine ecosystems.Due to ecological risks associated with pollutants released from offshore sediments,more research on the influence of global offshore pollution based on marine geology is undoubtedly needed.
基金Supported by the Natural Science Foundation of Zhejiang Province,China(No.LY20D040001)the National Undergraduate Innovation and Entrepreneurship Training Program of China。
文摘The growth of tidal flats off Zhejiang coasts in southwestern China has provided substantial areas for local agriculture and construction activities.To evaluate modern and future development of tidal flats in the region,a good understanding of sediment sources is necessary.Previous research has concluded that the Changjiang(Yangtze)River is the dominant supplier of sediments to this part of the southeast Chinese coast,despite the fact that sediment delivery from this source has been decreased markedly in the past two decades.In this study,we investigated the sources of tidal flat sediments,and the magnetic and geochemical properties of recent tidal flat sediments along the Zhejiang coast were compared with those discharged from rivers.Magnetic and geochemical properties of the tidal flat samples reveal statistically distinct sediment provenance groups.The magnetic and geochemical scatter plots show that the suspended sediment samples are naturally divided into two different groups,one including the Changjiang River and Qiantang River material,and the other including the Jiaojiang,Oujiang,and Feiyun Rivers that located in the central and southern parts of the study areas.At last,a binary source of tidal flat sediments along the Zhejiang coast was determined,with the substantial majority originating from local rivers,while a much smaller proportion emanates from the Changjiang River to the north.We conclude that the sediment contribution of the Changjiang River to tidal flat development in the region has been markedly overestimated,with important implications for management.
基金Key Research and Development Projects in Guangdong Province(2019B111101002)Program of Science,Technology and Innovation Commission of Shenzhen Municipality(JCYJ20170413164957461,GGFW2017073114031767)
文摘Following previous studies of the rainfall forecast in Shenzhen owing to landfalling tropical cyclones(TCs),a nonparametric statistical scheme based on the classification of the landfalling TCs is applied to analyze and forecast the rainfall induced by landfalling TCs in the coastal area of Guangdong province,China.All the TCs landfalling with the distance less than 700 kilometers to the 8 coastal stations in Guangdong province during 1950—2013 are categorized according to their landfalling position and intensity.The daily rainfall records of all the 8 meteorological stations are obtained and analyzed.The maximum daily rainfall and the maximum 3 days’accumulated rainfall at the 8 coastal stations induced by each category of TCs during the TC landfall period(a couple of days before and after TC landfalling time)from 1950 to 2013 are computed by the percentile estimation and illustrated by boxplots.These boxplots can be used to estimate the rainfall induced by landfalling TC of the same category in the future.The statistical boxplot scheme is further coupled with the model outputs from the European Centre for Medium-Range Weather Forecasts(ECMWF)to predict the rainfall induced by landfalling TCs along the coastal area.The TCs landfalling in south China from 2014 to 2017 and the corresponding rainfall at the 8 stations area are used to evaluate the performance of these boxplots and coupled boxplots schemes.Results show that the statistical boxplots scheme and coupled boxplots scheme can perform better than ECMWF model in the operational rainfall forecast along the coastal area in south China.
文摘This study surveyed the levels of boundary layer surface turbulence across a West African climate region. Five years (2011-2015) temperature and wind speed data at synoptic hours 0000 Hr, 0600 Hr, 1200 Hr and 1800 Hr within 0.125<span style="white-space:nowrap;">°</span> grid resolution was sourced from Era-Interim Reanalysis platform at 1000 mbar pressure level. Using the Richardson (Ri) number technique, results showed that mechanical turbulence of Ri range 0.04 - 0.57 dominates across the surface layer for study locations of Port Harcourt, Enugu, Jos, Kano and Maiduguri than thermal turbulence. However, the least turbulent area was the coastal zone of surveyed region. Results also indicated that the vertical height (L) at which thermal turbulence replaces mechanical turbulence across study locations ranged from 20 - 250 m with lowest replacement levels (20 - 50 m) occurring mainly in the coastal area of Port Harcourt during periods of dawn. The most turbulent periods in the southern coastal location of study region were during key rainy periods from June-August while that for the rest far northern inland areas occur during the dry season/early rainy periods i.e. November-May. The implication of the lower surface turbulence/replacement level within coastal domains most especially during periods of dawn is that emission releases near surface layer will be dispersed after initial rise due to buoyancy at horizontal levels thereby increasing ground level pollutants concentration across sensitive receptors that are close to emission source. At heights of thermal turbulence replacement, emission releases will be transported vertically and then dispersed further away from emission sources, thus impacting sensitive receptors at farther distances. This is the atmospheric boundary layer dynamics that makes ground level pollution worse in the coastal city of Port Harcourt in recent times during periods of dawn. Efforts must be made by concerned Stakeholders towards ensuring that emissions are reduced during the periods of dawn within and around coastal environments.
基金supported by the National Natural Science Foundation of China(NSFC)(Nos.42175115,41775117)the Guangdong Basic and Applied Basic Research Foundation(No.2022A1515011864)+4 种基金the Guangdong Major Project of Basic and Applied Basic Research(No.2020B0301030004)the Science and Technology Innovation Committee of Guangzhou(No.201803030010)the Scientific and Technological Innovation Team Project of Guangzhou Joint Research Center of Atmospheric Sciences,Science and Technology Program of Guangdong Province(Science and Technology Innovation Platform Category)(No.2019B121201002)the Guangdong Province Key Laboratory for Climate Change and Natural Disaster Studies(No.2020B1212060025)the Fundamental Research Funds for the Central Universities,Sun Yat-sen University(22qntd1907).
文摘Nitrous acid(HONO)is an important source of hydrogen oxides(HOx),which affects air quality,the atmospheric oxidation capacity,and human health.Here,we present ambient measurements of the HONO concentrations in Zhuhai,a coastal city in Southern China,from February 7 to March 15,2021.The campaign was classified into two periods during(P1)and after(P2)the Spring Festival holidays.The average HONO mixing ratio during P2(1.19±0.85 ppbv)was much higher than that during P1(0.24±0.18 ppbv),likely due to the contribution of homogeneous HONO formation.During nighttime,the heterogeneous conversion rate during P2(0.0089/hr)was considerably higher than that during P1(0.0057/hr),suggesting a higher heterogeneous NO_(2) conversion potential.However,the heterogeneous NO_(2) conversion was the dominant way during P1 with a high percentage of 88%,while comparable ratios of heterogeneous and homogeneous formation were found(54%vs.46%)during P2,indicating that the homogeneous formation was also important during P2.During daytime,homogeneous reaction was the major known pathway,with a contribution of 16%during P1 and 27%during P2,leaving large unknown HONO sources which reasonably correlated with the photo-enhanced NO_(2) conversion.Two case scenarios were additionally explored,showing that there might be a primary emission source during one scenario(February 17-18)and vehicle emissions might be the major unknown HONO source for another scenario(March 3–5).The results suggest that large unknown daytime sources still exist which need more future ambient and laboratory studies.
文摘Winter chilling is critical for most temperate fruits and perennial plants during the winter season. Most fruit and nut trees require a prolonged period of chilling to break their dormant stage and bloom when spring arrives. This research’s primary objective was to calculate the chill hour’s accumulation in each county in South Carolina based on the historical hourly air temperature data for the last ten years (2010-2020). The chilling hours model used to calculate the daily chill hours was based on the number of hours when the air temperature was between 32<span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#FFFFFF;">°</span>F to 45<span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#FFFFFF;">°</span>F (0 to 7.2<span style="color:#4F4F4F;font-family:-apple-system, "font-size:16px;white-space:normal;background-color:#FFFFFF;">°</span>C). The total chill hours for each county were then determined by accumulating the daily chill hours <span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">from</span></span></span><span><span><span style="font-family:" color:red;"=""> </span></span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">October to June. Our results showed that among the different counties in South Carolina, on average Laurens County had the most prolonged chill hours (1419 hrs). The chill hours were higher between November to March, and counties near the coastal regions had fewer chill hours than the counties in the inland areas. For example, Beaufort, Charleston, Berkeley, Horry, and Dorchester counties that are located near the coastal region had fewer chill hours. In contrast, counties located in the inland areas like Laurens, Chester, Lancaster, and York recorded the most prolonged chill hours. Our results suggest that selecting high chilling requirement crops for the inland areas and low chilling requirement crops for coastal areas would be appropriate. Farmers in South Carolina can use this information to plan their crop selection and management.</span></span></span>
