This study assesses the performance of three high-resolution regional numerical models in predicting hourly rainfall over Hainan Island from April to October for the years from 2020 to 2022.The rainfall amount,frequen...This study assesses the performance of three high-resolution regional numerical models in predicting hourly rainfall over Hainan Island from April to October for the years from 2020 to 2022.The rainfall amount,frequency,intensity,duration,and diurnal cycle are examined through zoning evaluation.The results show that the China Meteor-ological Administration Guangdong Rapid Update Assimilation Numerical Forecast System(CMA-GD)tends to forecast a higher occurrence of light precipitation.It underestimates the late afternoon precipitation and the occurrence of short-duration events.The China Meteorological Administration Shanghai Numerical Forecast Model System(CMA-SH9)reproduces excessive precipitation at a higher frequency and intensity throughout the island.It overestimates rainfall during the late afternoon and midnight periods.The simulated most frequent peak times of rainfall in CMA-SH9 are 0-1 hour deviations from the observed data.The China Meteorological Administration Mesoscale Weather Numerical Forecasting System(CMA-MESO)displays a similar pattern to rainfall observations but fails to replicate reasonable structure and diurnal variation of frequency-intensity.It underestimates the occurrence of long-duration events and overestimates related rainfall amounts from midnight to early morning.Notably,significant discrepancies are observed in the predictions of the three models for areas with complex terrain,such as the central,southeastern,and southwestern regions of Hainan Island.展开更多
Hainan Island located at the southernmost tip of the continental crust of the South China Plate,has high terrestrial heat-flow values,widely-distributed hot springs,and rich geothermal resources.Intensified researches...Hainan Island located at the southernmost tip of the continental crust of the South China Plate,has high terrestrial heat-flow values,widely-distributed hot springs,and rich geothermal resources.Intensified researches on the origin and potentials of geothermal resources can promote Hainan Island's development into a clean energy island.To determine the geological conditions for the formation of geothermal resources in southern Hainan Island,we collected core samples of granites from the Baocheng batholith in southern Hainan Island and conducted systematic analysis in respect of petrology,geochronology,geochemistry,and petrophysical property.The results of this study are as follows.The Baocheng batholith in the southern Hainan Island has a crystallization age of 98.42±0.56 Ma,making it the product of magmatism in the early stage of the Late Cretaceous.It mainly consists of high-K calc-alkaline granites,which were intruded by intermediate-to-mafic veins.The Baocheng batholith has a high radioactive heat generation rate of 2.712-6.843μW/m^(3),with an average of 3.846μW/m^(3),a radioactive heat-flow value of 30.768 μW/m^(2)and a heat-flow contribution rate of 38.95%-43.95%.As shown by the results of their thermophysical property analysis,the granites have high thermal conductivity and can serve as highquality geothermal reservoirs.In combination with previous geological and geophysical data,the geothermal model of the Lingshui area was established in this study.The deep structure indicates the presence of high-conductivity and low-resistivity layers in the basement of the Baocheng batholith.It can be inferred thereby that asthenospheric upwelling may occur and that there exist two magma vents at depth in the batholith.Therefore,magmatic heat at depth and granites with high radioactive heat generation rate serve as the main heat sources in the Lingshui area.展开更多
The toxic heavy metal mercury(Hg)has significantly enhanced the global Hg cycle influenced by human activities over the last century.In this study,we presented a high-resolution Hg deposition history between∼1780 and...The toxic heavy metal mercury(Hg)has significantly enhanced the global Hg cycle influenced by human activities over the last century.In this study,we presented a high-resolution Hg deposition history between∼1780 and 2015 AD in a sediment core from Xincun Lagoon,located in the southeastern Hainan Island,South China,and analyzed it in conjunction with geochemical elements,grain-size distribution,organic matter,and HYSPLIT backward trajectory simulation.The objective was to investigate the influencing factors affecting historical Hg deposition in relatively remote regions and assess the extent of the effects of natural background and human activities.The results showed that the Hg in the sediment was deposited primarily through atmospheric deposition,which was closely related to regional and even global human activities.Anthropogenic Hg contamination increased gradually from the 1830s to 1850s,possibly due to Hg emissions from Opium Wars I and II occurring in southeastern China.High broad peaks of anthropogenic Hg were observed during the 1910s to 1950s and in the 1980s,likely associated with the two world wars and modern Chinese wars.In addition,a further sharp increase in anthropogenic Hg from the mid-1970s to the present occurred,likely originating from the intense industrial activities in China triggered by the reform and opening-up policy of China in 1978 and some countries in Southeast Asia.展开更多
Using over 3 500 first P arrival times recorded by nine digital seismic stations from Hainan Digital Seismic Net-work during 1999～2005,a 3-D P-wave velocity model of the crust under Hainan Island and adjacent regions...Using over 3 500 first P arrival times recorded by nine digital seismic stations from Hainan Digital Seismic Net-work during 1999～2005,a 3-D P-wave velocity model of the crust under Hainan Island and adjacent regions has been determined. The results show that the pattern of velocity anomalies in the shallower upper crust is somewhat associated with the surface geological tectonics in the region. A relative low-velocity anomaly appears north of the Wangwu-Wenjiao fault zone and a relative high-velocity anomaly appears south of the Wangwu-Wenjiao fault zone,corresponding to the depressed areas in north Hainan Island,where many volcanoes are frequently active and geothermal values are relatively higher,and the uplifted and stable regions in central and south of the Hainan Is-land. In the middle and lower crust velocities are relatively lower in east Hainan than those in west Hainan,possi-bly suggesting the existence of the upwelling of hot materials from the mantle in east Hainan. The pattern of veloc-ity anomalies also indicates that NW faults,i.e.,the Puqian-Qinglan fault,may be shallower,while the E-W Wangwu-Wenjiao fault may be deeper,which perhaps extends down to Moho depth or deeper.展开更多
Hainan Island is a seismic active region, where Qiongshan M7.5 earthquake occurred in 1605 and several seismic belts appeared in recent years, especially the NS trending seismic belt(NSB) located in the northeast part...Hainan Island is a seismic active region, where Qiongshan M7.5 earthquake occurred in 1605 and several seismic belts appeared in recent years, especially the NS trending seismic belt(NSB) located in the northeast part of the island. Here is also a magmatic active region.The lava from about 100 volcanoes covered more than 4000 km^2. The latest eruptions occurred on Ma'anlinge Lei Huling volcanoes within 10,000 years. The neotectonic movement has been determined by geological method in the island and its adjacent areas. In the paper, the present-day 3D crustal movement is obtained by using Global Positioning System(GPS) data observed from 2009 to 2014 and leveling observations measured in 1970s and 1990s respectively. The results show the horizontal movement is mainly along SEE direction relative to the Eurasian Plate. The velocities are between 4.01 and 6.70 mm/a. The tension rate near the NSB is less than 1 mm/a. The vertical movement shows the island uplifts as a whole with respect to the reference benchmark Xiuyinggang. The average uplifting rate is 2.4 mm/a. The rates are 2-3 mm/a in the northwest and 3-5mm/a in the northwest. It shows the deformation pattern of the southwest island is upward relative to the northeast, which is different from the result inferred from the coastal change and GPS.Haikou and its adjacent region present a subsidence in a long time. The southern part of the middle segment of the Wangwu-Wenjiao fault uplifts relative to the northern. Meanwhile, the western part uplifts relative to the eastern NSB. The vertical crustal motion and the two normal faults nearly correspond to the terrain. The NSB is located along the Puqiangang-Dazhibo fault, which is assessed as a segmented fault with a dip of 80°-90° and partly exposed. The 3D deformations and other studies reveal the present activities of earthquakes, volcanoes and the faults. The small earthquakes will still occur in the NS belt and the volcanoes are not active now.展开更多
Using the 25-h continuing hydrographic observations at three successive stations in February 2012 and the mooring time series of current observations from January to March 2015,the tidal currents and tidal energy flux...Using the 25-h continuing hydrographic observations at three successive stations in February 2012 and the mooring time series of current observations from January to March 2015,the tidal currents and tidal energy fluxes in the coastal waters east of Hainan Island in the northwestern South China Sea were analyzed.The diurnal and semidiurnal(using K_(1) and M_(2) as proxies,respectively)tidal currents and associated isopycnal undulations were derived with harmonic analysis.Results show that the velocities of the diurnal and semidiurnal tides derived from the 25-h observations are comparable to those from the mooring series.The semi-major axes of the tidal ellipses were O(4-7 cm/s)for barotropic tides and O(2-4 cm/s)for baroclinic tides.The directions were in NE-SW at deeper stations to N-S at the shallowest station for the diurnal tide and from NW-SE to NE-SW for the semidiurnal tide.Both the diurnal and semidiurnal isopycnal fl uctuations reached O(5 m),O(8 m),and O(10 m)at the cross-shelf stations(H03,H04,and H05)from 35 m,45 m,to 55 m,respectively,showing insignifi cant vertical variation,and the barotropic signals were predominate.The baroclinic diurnal tide showed fi rst-mode structures at H03-05,as does the semidiurnal tide at H03.The semidiurnal tide at H04 and H05 exhibited higher-mode structures.The time series of both the alongshore and cross-shore components reveal the vertically propagation features of the baroclinic tidal phase and energy.The calculated horizontal energy fl uxes of the diurnal and semidiurnal internal tides decreased from O(0.1 W/m)at H05 to O(0.01 W/m)at H03,implying a propagation and dissipation of energy from off shore to inshore.展开更多
[Objective] The aim of this paper was to analyze the risks in the typhoon hazard factors in Hainan Island. [Method] Taking the theory and method of natural disasters evaluation as starting point and supporting point, ...[Objective] The aim of this paper was to analyze the risks in the typhoon hazard factors in Hainan Island. [Method] Taking the theory and method of natural disasters evaluation as starting point and supporting point, and selecting Hainan province as the research target, where the typhoon disaster occurred relatively serious, based on the typhoon data during 1958-2008, with happening frequency of typhoon hazard-formative factors, maximum rainfall, potentially devastating effects of typhoon winds as evaluation indexes, the typhoon disaster risk evaluation index system and evaluation model were established. And by dint of GIS technique, Hainan island typhoon disaster risk zoning of hazard-formative factors and grading were prepared. [Result] Typhoon occurred frequently in Hainan and there were no certain rules of its annual changes. The monthly changes mainly happed during July to October. The highly dangerous area of typhoon mainly distributed in east coast area. The annual daily precipitation decreased from central mountainous area to the surroundings; typhoon hided in the destructive highly risked area in east, south and west area; low disastrous area occurred in the middle area; the risks of disastrous factors weakened from east area to west area. The distribution area of each level was that low dangerous area>mild dangerous area>highly dangerous area>secondary low dangerous area>highly dangerous area. [Conclusion] The study supplied scientific reference for the government in the united organization and direction of disaster relief work.展开更多
Objective: To analyze the distribution characteristics and clinical significance of SLCO1B1 and ApoE gene polymorphisms of the Li people in Hainan Island. Method: Selecting 502 high school students of the Li people fr...Objective: To analyze the distribution characteristics and clinical significance of SLCO1B1 and ApoE gene polymorphisms of the Li people in Hainan Island. Method: Selecting 502 high school students of the Li people from five cities and counties in Hainan Island (namely, Qiongzhong County, Dongfang City, Ledong County, Baoting County and Wuzhishan City) as research subjects in September, 2019;Applying PCR-fluorescence probe method to detect SLCO1B1 and ApoE genotypes of the Li people in Hainan Island, and statistically analyzing the distribution characteristics of gene frequency and the distribution differences in gene polymorphisms between different genders. Meanwhile, detecting the SLCO1B1 and ApoE gene of 527 people from the Han people in five regions mentioned before, so as to analyze the distribution differences of the SLCO1B1 and ApoE gene between the Han people and the Li people. Results: The frequency of each genotype of SLCO1B1 in the Li people in Hainan Island is: *1a/*1a 6.77%, *1a/*1b 27.09%, *1b/1b 41.63%, *1a/*5 0.00%, *1a/*15 4.78%, *1b/15 16.93%., *5/*5 0.00%, *5/*15 0.00%, *15/*15 2.79%;And that of ApoE is: e2/e2 0.40%, e2/e3 17.73%, e2/e4 2.39%, e3/e3 65.54%, e3/e4 12.55%, e4/e4 1.39%. There is no significant difference (P > 0.05) in other genotypes except weak metabolic genotypes (*5/*5, *5/*15 and *15/*15) between the Han and the Li peoples. Conclusion: The gene frequency of SLCO1B1 weak metabolic genotype is dramatically higher in the Li people of Hainan Island than that of the Han people in both Hainan Island and Central and South China, but there is no significant difference in ApoE gene frequency among them. Therefore, clinicians should adjust the dosage of statins and select the types of lipid-lowering drugs according to the differences in patients’ genotypes, and strengthen the management of patients with ApoE4 risk gene.展开更多
Marine benthic dinoflagellates in the genus Coolia were reported in both tropical and temperate regions.We conducted a morphological and phylogenetic characterization of Coolia species from Hainan Island,South China S...Marine benthic dinoflagellates in the genus Coolia were reported in both tropical and temperate regions.We conducted a morphological and phylogenetic characterization of Coolia species from Hainan Island,South China Sea.The morphologies of three Coolia species were similar to those of the original descriptions of Coolia canariensis,C.tropicalis,and C.malayensis.In phylogenetic analyses based on the LSU rDNA and ITS regions(ITS1-5.8 S-ITS2),the Hainan strains of C.canariensis,C.tropicalis,and C.malayensis clustered within the clades of these species with other isolates from different areas.No differences(p-distance)in LSU rDNA sequences were found between the Hainan C.malayensis strains and the strains from New Zealand,Florida of USA,Malaysia,Japan,Dominican Republic and Guangxi and Hong Kong of China.For C.canariensis and C.tropicalis,no differences(p-distance)in the LSU rDNA sequences were found between the Hainan strains(D1 C2 and DS5 F4,respectively)and the Australian strains(NQAIF252 and NQAIF90,respectively).Our study reveals the morphological and genetic diversity of Coolia species from Hainan Island,South China Sea,which provides a detailed understanding of Coolia species of this area.展开更多
Since the recognition of the Indosinian orogeny in northern Vietnam,Triassic orogens have been widely identified around the western and southwestern boundaries of the South China block.The paleo-Tethys sutures stretch...Since the recognition of the Indosinian orogeny in northern Vietnam,Triassic orogens have been widely identified around the western and southwestern boundaries of the South China block.The paleo-Tethys sutures stretch from west to southeast,from Jinshajiang-Ailaoshan via NE Vietnam to Hainan Island;these sutures exhibit and develop voluminous Permian-early Triassic magmatism and numerous high-strain shear zones.As ophiolites related to the paleo-Tethys are lacking on Hainan Island,the eastward extension of the Indosinian orogeny and subduction and closure time of the paleo-Tethys Ocean on Hainan Island remain controversial.Here,an integrated kinematic and geochronological study has been conducted on two shear zones,called the Xiaomei and Mangsan shear zones.U-Pb zircon dating yields an age of early Triassic(252-251 Myr)for Xiaomei syntectonic granites which formed in the same tectonic setting and presented the similar nanoparticles to the Indosinian granites from Ailaoshan ductile shear zone,including the strawberry-like and flower-like nanoparticles.The NE-trending Mangsan shear zone represented by the gneissic granites with middle Permian ages(264-262 Myr)formed in the same tectonic setting as the Wuzhi-shan granites that were proposed as I-type granites.These middle Permian gneissic granites with arc affinity may represent an arc setting related to the NW subduction of the paleo-Tethys.The analyses reveal that granites with late Triassic ages(235-232 Myr)in the Xiaomei shear zone have the characteristics of A-type granites.The late Triassic extensional events on Hainan Island may be related to the subduction of the paleo-Pacific Plate beneath the East Asian continent.展开更多
The Mesoproterozoic Baoban Group is the oldest basement in Hainan Island and has played an important role in Columbia(Nuna)supercontinent reconstructions.The Mesoproterozoic granitic intrusions in the Baoban Group are...The Mesoproterozoic Baoban Group is the oldest basement in Hainan Island and has played an important role in Columbia(Nuna)supercontinent reconstructions.The Mesoproterozoic granitic intrusions in the Baoban Group are the most widely-exposed Precambrian magmatic rocks and are the key to understanding the tectonic settings of Hainan Island and its relationship with the South China Block and the Columbia supercontinent.New LA-ICP-MS zircon U-Pb dating on three mylonitic granite samples from the Tuwaishan and Baoban areas yield ages ranging from 1447 Ma to 1437 Ma,representing the absolute timing of the emplacement of the granitic intrusions.Combined with previously published geochronological data for rocks from the Baoban Group and regional mafic intrusions,it is concluded that the Baoban Group formed at 1460-1430 Ma,coeval with the emplacement of the granitic and mafic intrusions.New in-situ zircon LuHf isotope analyses for the three mylonitic granite samples yielded positiveε(t)values,ranging from+0.49 to+8.27,with model ages(T~C)ranging from 2181 Ma to 1687 Ma,suggesting that the granitic intrusions originated from a mixed source of Paleoproterozoic crust with juvenile crust.New zircon trace element data show characteristics of high Th/U values of 0.24-1.50,steep slopes from LREE to HREE and negative Pr,Eu anomalies with positive Ce,Sm anomalies,representing typical magmatic zircons formed in continental crust.Compared with available magmatic and detrital zircon ages from Precambrian rocks in the Cathaysia Block,Yangtze Block and western Laurentia,it is inferred that Hainan Island was separated from both the Cathaysia Block and the Yangtze Block,instead being connected with western Laurentia in the Columbia supercontinent.Considering the decreasing tendency of basin deposition time along the western margin of Laurentia,it is proposed that Hainan Island was located to the north or northwest of the Belt-Purcell Supergroup,along the western margin of Laurentia,during the breakup of the Columbia supercontinent.展开更多
The relationship between storm activity and global warming remains uncertain.To better understand storm–climate relationships,coastal lagoon deposits are increasingly being investigated because they could provide hig...The relationship between storm activity and global warming remains uncertain.To better understand storm–climate relationships,coastal lagoon deposits are increasingly being investigated because they could provide high-resolution storm records long enough to cover past climate changes.However,site-specific sediment dynamics and high barriers may bias storm reconstructions.Here,we aimed to investigate these factors through the reconstruction of five distinct storm records(XCL-01,XC-03,XC-06,XC-07,XC-08)from different water depths in a lagoon with a high barrier(i.e.,Xincun Lagoon of Hainan Island).Sediment cores were characterized using high-resolution grain size and XRF measurements,to identify storm events.These data were coupled with a numerical simulation to obtain bed shear stress data with high-spatial resolution to better understand storm-induced sediment transport mechanisms.^(210) Pb dating and Pb pollution chronostratigraphic markers indicated that the chronology of the storm deposit sequences of the cores span the period between 117 a and 348 a.The grain size and XRF results indicated numerous,highly variable and short-duration fluctuations,suggesting that storm-induced coarse-grained sediments were deposited at these core sites.The inconsistent storm events recorded in these cores suggest that these sites have different preservation potentials for storm deposits.However,the consistence between storm sediment records and historical documents for Core XCL-01 indicates that high-barrier lagoons could provide long-term storm event records with high preservation potential.展开更多
The diversity,community composition and 16 S rRNA gene abundance of bacterioplankton along a transect across an upwelling area off the eastern coast of Hainan Island(the Qiongdong upwelling)were investigated in August...The diversity,community composition and 16 S rRNA gene abundance of bacterioplankton along a transect across an upwelling area off the eastern coast of Hainan Island(the Qiongdong upwelling)were investigated in August of 2016 using high throughput sequencing and quantitative PCR assay of 16 S rRNA genes.Compared with the offshore stations,the inner-shelf stations had higher bacterial gene abundance(up to 3 fold)and operational taxonomic unit richness,a result of the influence of upwelled and fresher waters.Overall,a majority of the reads were affiliated with Gammaproteobacteria(11%-74%)and Alphaproteobacteria(14%-43%).The structure of the bacterial community was significantly affected by salinity,dissolved oxygen,NO_(3)^(-) and NH_(4)^(+),which also defined the physicochemical features of the upwelled waters.Horizontally,the relative abundances and gene abundances of Rhodobacteraceae,SAR86,Cyanobacteria and Bacteroidetes in eutrophic zone decreased from the inner to outer shelves and slope,whereas Alteromonas,Vibrio and Oceanospirillaceae exhibited an opposite trend.This study stresses the riverine influence on the oceanographic condition and spatial variability of bacterioplankton diversity and distribution in the Qiongdong upwelling.展开更多
This study reveals a significant positive connection between autumn non-tropical-cyclone heavy rainfall on Hainan Island and the intensity of Eastern Pacific(EP)El Ni?o events.That is,the amount of rainfall in super E...This study reveals a significant positive connection between autumn non-tropical-cyclone heavy rainfall on Hainan Island and the intensity of Eastern Pacific(EP)El Ni?o events.That is,the amount of rainfall in super EP El Ni?o years is more than that in normal EP El Ni?o years.Comparing EP El Ni?o years of different intensities,the cooler sea surface temperature in the northwestern Pacific during super EP El Ni?o years stimulates a negative surface latent heat flux(LHF)anomaly and abnormal anticyclonic circulation at 850 hPa.Under these conditions,an abnormal zonal vertical circulation develops in the northern South China Sea once a positive LHF anomaly and abnormal cyclonic circulation(ACC)at 850hPa occur in the Beibu Gulf.The abnormal zonal vertical circulation further strengthens the ascending motion over Hainan Island,as the critical factor that leads to excessive rainfall.Further analysis shows that the positive LHF anomaly,which can be attributed to the increased latent heat transfer which resulted from the increased surface wind speed,is an important trigger for the ACC.However,the ACC is also the supplier of favorable moisture conditions because it intensifies vapor convergence over Hainan Island and meridionally transports moisture from the South China Sea to northeastern Hainan Island,thereby generating heavy rainfall.This paper emphasizes that the impact of El Ni?o events,especially super El Ni?o events,on rainfall over Hainan Island cannot be ignored,even if the traditional view is that frequent rainfall occurs mainly in La Ni?a years.展开更多
This study investigates the roles of the boreal summer intraseasonal oscillation(BSISO)in the diurnal rainfall cycle over Hainan Island during the warm season(April-September)using 20-year satellite-based precipitatio...This study investigates the roles of the boreal summer intraseasonal oscillation(BSISO)in the diurnal rainfall cycle over Hainan Island during the warm season(April-September)using 20-year satellite-based precipitation,ERA5 and the outgoing longwave radiation data with the phase composite analysis method.Results show that the spatial distributions of the hourly rainfall anomaly significantly change under the BSISO phases 1-8 while no clear variations are found on the daily and anomaly daily area-averaged rainfall over the island.During the BSISO phase 1,the rainfall anomaly distinctly increases in the morning over the southwest and late afternoon over the northeast of the island,while suppressed convection occurs in the early afternoon over the southwest area.Under this circumstance,strong low-level westerly winds bring abundant moisture into the island,which helps initiate the nocturnal-morning convection over the south coastal area,and drives the convergence region of sea breeze fronts to concentrate into the northwest.Opposite to Phase 1,an almost completely reversed diurnal cycle of rainfall anomaly is found in Phase 5,whereas a positive anomalous rainfall peak is observed in the early afternoon over the center while negative peaks are found in the morning and late afternoon over the southwest and northeast,owing to a strong low-level northeasterly anomaly flow,which causes relatively low moisture and enlarges a sea-breeze convergence area over the island.During Phase 8,strongest moisture is found over the island all through the day,which tends to produce highest rainfall in the afternoon with enhanced anomalous northerly.These results further indicate that multiscale interactions between the large-scale circulations and local land-sea breeze circulations play important roles in modulating diurnal precipitation cycles over the tropical island.展开更多
Studies on the aerolite fragments from Baisha crater, Hainan Island prove that they belong to calcium-rich achondrite which are relicts of cratering meteorite of the Baisha crater.These flat-ball shaped aerolite fragm...Studies on the aerolite fragments from Baisha crater, Hainan Island prove that they belong to calcium-rich achondrite which are relicts of cratering meteorite of the Baisha crater.These flat-ball shaped aerolite fragments, size being 21cm×18.5cm×8.7cm, were found in a creek within the Baisha crater. This hard aerolite weigh 3.75 kg with a density of 3.46g/cm<sub>3</sub>. It is mantled by a 0.1-0.5cm thick ,brown shell and its fresh section is dark-grey. The aerolite is characterized by porphyritic texture and no spherulitic texture has been found. Microscopic examination, X-ray diffraction analysis and electronic probe展开更多
Hainan Island is the second largest island inChina. It is situated on the Nanhai Sea(SouthChina Sea) and faces Guangdong Province acrossQiongzhou Strait (海峡).Hainan Province was established(建立)in 1988. It consists...Hainan Island is the second largest island inChina. It is situated on the Nanhai Sea(SouthChina Sea) and faces Guangdong Province acrossQiongzhou Strait (海峡).Hainan Province was established(建立)in 1988. It consists of HainanIsland, Xisha Islands, Zhongsha Islands, NanshaIslands and the vast sea areas around them.展开更多
The actual and potential water erosion rates of soils with different land covers in Hainan Island, China,were estimated based on the universal soil loss equation (USLE) and a 1:200 000 Soils and Terrain Digital Databa...The actual and potential water erosion rates of soils with different land covers in Hainan Island, China,were estimated based on the universal soil loss equation (USLE) and a 1:200 000 Soils and Terrain Digital Database (SOTER) database, from which soil water erosion factors could be extracted. 92.8% of the whole island had a current erosion rate of lower than 500 t km-2 a-1. Soil erosion risk was considered to be high because of its abundant rainfall. Without vegetation cover, the potential soil erosion rate would be extremely high and 90.8% of the island would have a soil erosion rate higher than 2 500 t km-2 a-1. Relative erosion vulnerability of different soil zones, landform types, and lithological regions of the island was compared by introducing a relative erosion hazard parameter α. Cambosols developed from siltstone and mudstone in low hill regions were pinpointed as soils with the highest erosion risk in the island.展开更多
During the past half century, the land utilization of Hainan Island has undergone a rapid development,but in the meanwhile, soil degradation occurs. Analysis on some basic data of the soil series collected frommore th...During the past half century, the land utilization of Hainan Island has undergone a rapid development,but in the meanwhile, soil degradation occurs. Analysis on some basic data of the soil series collected frommore than 100 soil profiles at the end of the 1990s and beginning of this century, in combination with dataavailable, showed that soils there suffered significant decline in organic matter, experienced P and K deficiencywith soil K going on losing and undergone acidification with continuing trend. The current situation calls forstrategies to build up Hainan into an important province of sound ecology by restoring forests, to improvefood quality by implementing K supplement projects, to combat soil acidification by ameliorating the soils andgrowing leguminous crops and to ensure health of the people by developing dairy production and increasingthe daily Ca uptake by the people.展开更多
基金Regional Innovation and Development Joint Fund of National Natural Science Foundation of China(U21A6001)China Meteorological Administration Innovation and Develop-ment Project(CXFZ2021Z008)Hainan Provincial Meteorolo-gical Bureau Business Improvement Project(hnqxSJ202101)。
文摘This study assesses the performance of three high-resolution regional numerical models in predicting hourly rainfall over Hainan Island from April to October for the years from 2020 to 2022.The rainfall amount,frequency,intensity,duration,and diurnal cycle are examined through zoning evaluation.The results show that the China Meteor-ological Administration Guangdong Rapid Update Assimilation Numerical Forecast System(CMA-GD)tends to forecast a higher occurrence of light precipitation.It underestimates the late afternoon precipitation and the occurrence of short-duration events.The China Meteorological Administration Shanghai Numerical Forecast Model System(CMA-SH9)reproduces excessive precipitation at a higher frequency and intensity throughout the island.It overestimates rainfall during the late afternoon and midnight periods.The simulated most frequent peak times of rainfall in CMA-SH9 are 0-1 hour deviations from the observed data.The China Meteorological Administration Mesoscale Weather Numerical Forecasting System(CMA-MESO)displays a similar pattern to rainfall observations but fails to replicate reasonable structure and diurnal variation of frequency-intensity.It underestimates the occurrence of long-duration events and overestimates related rainfall amounts from midnight to early morning.Notably,significant discrepancies are observed in the predictions of the three models for areas with complex terrain,such as the central,southeastern,and southwestern regions of Hainan Island.
基金The authors would like to extend gratitude to the fund from multiple scientific research programs,including subjects entitled Analysis and Geothermal Reservoir Stimulation Methods of Deep High-temperature Geothermal Systems in East China(No.:2021YFA0716004)Evaluation and Optimal Target Selection of Deep Geothermal Resources in the Igneous Province in South China(No.:2019YFC0604903)+1 种基金the National Key Research and Development Program of China,a project entitled Deep Geological Processes and Resource Effects of Basins(No.:U20B6001)the Joint Fund Program of the National Natural Science Foundation of China and Sinopec,and a project entitled Siting and Target Evaluation of Deep Geothermal Resources in Key Areas of Southeastern China(No.:P20041-1)of the Sinopec Science and Technology Research Program.
文摘Hainan Island located at the southernmost tip of the continental crust of the South China Plate,has high terrestrial heat-flow values,widely-distributed hot springs,and rich geothermal resources.Intensified researches on the origin and potentials of geothermal resources can promote Hainan Island's development into a clean energy island.To determine the geological conditions for the formation of geothermal resources in southern Hainan Island,we collected core samples of granites from the Baocheng batholith in southern Hainan Island and conducted systematic analysis in respect of petrology,geochronology,geochemistry,and petrophysical property.The results of this study are as follows.The Baocheng batholith in the southern Hainan Island has a crystallization age of 98.42±0.56 Ma,making it the product of magmatism in the early stage of the Late Cretaceous.It mainly consists of high-K calc-alkaline granites,which were intruded by intermediate-to-mafic veins.The Baocheng batholith has a high radioactive heat generation rate of 2.712-6.843μW/m^(3),with an average of 3.846μW/m^(3),a radioactive heat-flow value of 30.768 μW/m^(2)and a heat-flow contribution rate of 38.95%-43.95%.As shown by the results of their thermophysical property analysis,the granites have high thermal conductivity and can serve as highquality geothermal reservoirs.In combination with previous geological and geophysical data,the geothermal model of the Lingshui area was established in this study.The deep structure indicates the presence of high-conductivity and low-resistivity layers in the basement of the Baocheng batholith.It can be inferred thereby that asthenospheric upwelling may occur and that there exist two magma vents at depth in the batholith.Therefore,magmatic heat at depth and granites with high radioactive heat generation rate serve as the main heat sources in the Lingshui area.
基金Under the auspices of the National Natural Science Foundation of China(No.42071108,41671194)。
文摘The toxic heavy metal mercury(Hg)has significantly enhanced the global Hg cycle influenced by human activities over the last century.In this study,we presented a high-resolution Hg deposition history between∼1780 and 2015 AD in a sediment core from Xincun Lagoon,located in the southeastern Hainan Island,South China,and analyzed it in conjunction with geochemical elements,grain-size distribution,organic matter,and HYSPLIT backward trajectory simulation.The objective was to investigate the influencing factors affecting historical Hg deposition in relatively remote regions and assess the extent of the effects of natural background and human activities.The results showed that the Hg in the sediment was deposited primarily through atmospheric deposition,which was closely related to regional and even global human activities.Anthropogenic Hg contamination increased gradually from the 1830s to 1850s,possibly due to Hg emissions from Opium Wars I and II occurring in southeastern China.High broad peaks of anthropogenic Hg were observed during the 1910s to 1950s and in the 1980s,likely associated with the two world wars and modern Chinese wars.In addition,a further sharp increase in anthropogenic Hg from the mid-1970s to the present occurred,likely originating from the intense industrial activities in China triggered by the reform and opening-up policy of China in 1978 and some countries in Southeast Asia.
基金The special project of Detection of Haikou City Earthquake Active Faults from the Tenth Five-year Plan of China Earthquake Administration (0106512)Joint Seismological Science Foundation of China (105086)CAS Key Laboratory of Marginal Sea Geology (MSGL0503).
文摘Using over 3 500 first P arrival times recorded by nine digital seismic stations from Hainan Digital Seismic Net-work during 1999～2005,a 3-D P-wave velocity model of the crust under Hainan Island and adjacent regions has been determined. The results show that the pattern of velocity anomalies in the shallower upper crust is somewhat associated with the surface geological tectonics in the region. A relative low-velocity anomaly appears north of the Wangwu-Wenjiao fault zone and a relative high-velocity anomaly appears south of the Wangwu-Wenjiao fault zone,corresponding to the depressed areas in north Hainan Island,where many volcanoes are frequently active and geothermal values are relatively higher,and the uplifted and stable regions in central and south of the Hainan Is-land. In the middle and lower crust velocities are relatively lower in east Hainan than those in west Hainan,possi-bly suggesting the existence of the upwelling of hot materials from the mantle in east Hainan. The pattern of veloc-ity anomalies also indicates that NW faults,i.e.,the Puqian-Qinglan fault,may be shallower,while the E-W Wangwu-Wenjiao fault may be deeper,which perhaps extends down to Moho depth or deeper.
基金supported by the National Natural Science Foundation of China(41372345)
文摘Hainan Island is a seismic active region, where Qiongshan M7.5 earthquake occurred in 1605 and several seismic belts appeared in recent years, especially the NS trending seismic belt(NSB) located in the northeast part of the island. Here is also a magmatic active region.The lava from about 100 volcanoes covered more than 4000 km^2. The latest eruptions occurred on Ma'anlinge Lei Huling volcanoes within 10,000 years. The neotectonic movement has been determined by geological method in the island and its adjacent areas. In the paper, the present-day 3D crustal movement is obtained by using Global Positioning System(GPS) data observed from 2009 to 2014 and leveling observations measured in 1970s and 1990s respectively. The results show the horizontal movement is mainly along SEE direction relative to the Eurasian Plate. The velocities are between 4.01 and 6.70 mm/a. The tension rate near the NSB is less than 1 mm/a. The vertical movement shows the island uplifts as a whole with respect to the reference benchmark Xiuyinggang. The average uplifting rate is 2.4 mm/a. The rates are 2-3 mm/a in the northwest and 3-5mm/a in the northwest. It shows the deformation pattern of the southwest island is upward relative to the northeast, which is different from the result inferred from the coastal change and GPS.Haikou and its adjacent region present a subsidence in a long time. The southern part of the middle segment of the Wangwu-Wenjiao fault uplifts relative to the northern. Meanwhile, the western part uplifts relative to the eastern NSB. The vertical crustal motion and the two normal faults nearly correspond to the terrain. The NSB is located along the Puqiangang-Dazhibo fault, which is assessed as a segmented fault with a dip of 80°-90° and partly exposed. The 3D deformations and other studies reveal the present activities of earthquakes, volcanoes and the faults. The small earthquakes will still occur in the NS belt and the volcanoes are not active now.
基金Supported by the National Nature Science Foundation of China(Nos.41776034,41506018,41706025,41706129)the First-Class Discipline Plan of Guangdong Province(Nos.CYL231419012,231819002)+4 种基金the Matched Grant of Guangdong Ocean University(No.P15299)the PhD Start-up Grant of Guangdong Ocean University(No.R20022)the Project of Enhancing School with Innovation of Guangdong University(No.Q16303)the Project of Enhancing School with Innovation of Education Department of Guangdong Province(Nos.2018KQNCX082,2019KCXTF021)the Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(No.GML2019ZD0303)。
文摘Using the 25-h continuing hydrographic observations at three successive stations in February 2012 and the mooring time series of current observations from January to March 2015,the tidal currents and tidal energy fluxes in the coastal waters east of Hainan Island in the northwestern South China Sea were analyzed.The diurnal and semidiurnal(using K_(1) and M_(2) as proxies,respectively)tidal currents and associated isopycnal undulations were derived with harmonic analysis.Results show that the velocities of the diurnal and semidiurnal tides derived from the 25-h observations are comparable to those from the mooring series.The semi-major axes of the tidal ellipses were O(4-7 cm/s)for barotropic tides and O(2-4 cm/s)for baroclinic tides.The directions were in NE-SW at deeper stations to N-S at the shallowest station for the diurnal tide and from NW-SE to NE-SW for the semidiurnal tide.Both the diurnal and semidiurnal isopycnal fl uctuations reached O(5 m),O(8 m),and O(10 m)at the cross-shelf stations(H03,H04,and H05)from 35 m,45 m,to 55 m,respectively,showing insignifi cant vertical variation,and the barotropic signals were predominate.The baroclinic diurnal tide showed fi rst-mode structures at H03-05,as does the semidiurnal tide at H03.The semidiurnal tide at H04 and H05 exhibited higher-mode structures.The time series of both the alongshore and cross-shore components reveal the vertically propagation features of the baroclinic tidal phase and energy.The calculated horizontal energy fl uxes of the diurnal and semidiurnal internal tides decreased from O(0.1 W/m)at H05 to O(0.01 W/m)at H03,implying a propagation and dissipation of energy from off shore to inshore.
基金Supported by Hainan Natural Fund Program (809058)Key Operation Suggestion Program of China Meteorological Bureau " Typhoon Disaster Risk Evaluation and Division"
文摘[Objective] The aim of this paper was to analyze the risks in the typhoon hazard factors in Hainan Island. [Method] Taking the theory and method of natural disasters evaluation as starting point and supporting point, and selecting Hainan province as the research target, where the typhoon disaster occurred relatively serious, based on the typhoon data during 1958-2008, with happening frequency of typhoon hazard-formative factors, maximum rainfall, potentially devastating effects of typhoon winds as evaluation indexes, the typhoon disaster risk evaluation index system and evaluation model were established. And by dint of GIS technique, Hainan island typhoon disaster risk zoning of hazard-formative factors and grading were prepared. [Result] Typhoon occurred frequently in Hainan and there were no certain rules of its annual changes. The monthly changes mainly happed during July to October. The highly dangerous area of typhoon mainly distributed in east coast area. The annual daily precipitation decreased from central mountainous area to the surroundings; typhoon hided in the destructive highly risked area in east, south and west area; low disastrous area occurred in the middle area; the risks of disastrous factors weakened from east area to west area. The distribution area of each level was that low dangerous area>mild dangerous area>highly dangerous area>secondary low dangerous area>highly dangerous area. [Conclusion] The study supplied scientific reference for the government in the united organization and direction of disaster relief work.
文摘Objective: To analyze the distribution characteristics and clinical significance of SLCO1B1 and ApoE gene polymorphisms of the Li people in Hainan Island. Method: Selecting 502 high school students of the Li people from five cities and counties in Hainan Island (namely, Qiongzhong County, Dongfang City, Ledong County, Baoting County and Wuzhishan City) as research subjects in September, 2019;Applying PCR-fluorescence probe method to detect SLCO1B1 and ApoE genotypes of the Li people in Hainan Island, and statistically analyzing the distribution characteristics of gene frequency and the distribution differences in gene polymorphisms between different genders. Meanwhile, detecting the SLCO1B1 and ApoE gene of 527 people from the Han people in five regions mentioned before, so as to analyze the distribution differences of the SLCO1B1 and ApoE gene between the Han people and the Li people. Results: The frequency of each genotype of SLCO1B1 in the Li people in Hainan Island is: *1a/*1a 6.77%, *1a/*1b 27.09%, *1b/1b 41.63%, *1a/*5 0.00%, *1a/*15 4.78%, *1b/15 16.93%., *5/*5 0.00%, *5/*15 0.00%, *15/*15 2.79%;And that of ApoE is: e2/e2 0.40%, e2/e3 17.73%, e2/e4 2.39%, e3/e3 65.54%, e3/e4 12.55%, e4/e4 1.39%. There is no significant difference (P > 0.05) in other genotypes except weak metabolic genotypes (*5/*5, *5/*15 and *15/*15) between the Han and the Li peoples. Conclusion: The gene frequency of SLCO1B1 weak metabolic genotype is dramatically higher in the Li people of Hainan Island than that of the Han people in both Hainan Island and Central and South China, but there is no significant difference in ApoE gene frequency among them. Therefore, clinicians should adjust the dosage of statins and select the types of lipid-lowering drugs according to the differences in patients’ genotypes, and strengthen the management of patients with ApoE4 risk gene.
基金Supported by the National Natural Science Foundation of China(Nos.41606176,41576162,41606175)the IOC Yeosu Benthic Dinofl agellate Project。
文摘Marine benthic dinoflagellates in the genus Coolia were reported in both tropical and temperate regions.We conducted a morphological and phylogenetic characterization of Coolia species from Hainan Island,South China Sea.The morphologies of three Coolia species were similar to those of the original descriptions of Coolia canariensis,C.tropicalis,and C.malayensis.In phylogenetic analyses based on the LSU rDNA and ITS regions(ITS1-5.8 S-ITS2),the Hainan strains of C.canariensis,C.tropicalis,and C.malayensis clustered within the clades of these species with other isolates from different areas.No differences(p-distance)in LSU rDNA sequences were found between the Hainan C.malayensis strains and the strains from New Zealand,Florida of USA,Malaysia,Japan,Dominican Republic and Guangxi and Hong Kong of China.For C.canariensis and C.tropicalis,no differences(p-distance)in the LSU rDNA sequences were found between the Hainan strains(D1 C2 and DS5 F4,respectively)and the Australian strains(NQAIF252 and NQAIF90,respectively).Our study reveals the morphological and genetic diversity of Coolia species from Hainan Island,South China Sea,which provides a detailed understanding of Coolia species of this area.
基金This work was supported by the National Natural Science Foundation of China(Nos.41676048,U1701641,41776072,and 91328205)the Key Special Project for Introduced Talents Team of Southern Marine Science and Engineering Guangdong Laboratory(Guangzhou)(No.GML 2019ZD0205)the Innovation Academy of South China Sea Ecology and Environmental Engineering(No.ISEE 2020YB07).
文摘Since the recognition of the Indosinian orogeny in northern Vietnam,Triassic orogens have been widely identified around the western and southwestern boundaries of the South China block.The paleo-Tethys sutures stretch from west to southeast,from Jinshajiang-Ailaoshan via NE Vietnam to Hainan Island;these sutures exhibit and develop voluminous Permian-early Triassic magmatism and numerous high-strain shear zones.As ophiolites related to the paleo-Tethys are lacking on Hainan Island,the eastward extension of the Indosinian orogeny and subduction and closure time of the paleo-Tethys Ocean on Hainan Island remain controversial.Here,an integrated kinematic and geochronological study has been conducted on two shear zones,called the Xiaomei and Mangsan shear zones.U-Pb zircon dating yields an age of early Triassic(252-251 Myr)for Xiaomei syntectonic granites which formed in the same tectonic setting and presented the similar nanoparticles to the Indosinian granites from Ailaoshan ductile shear zone,including the strawberry-like and flower-like nanoparticles.The NE-trending Mangsan shear zone represented by the gneissic granites with middle Permian ages(264-262 Myr)formed in the same tectonic setting as the Wuzhi-shan granites that were proposed as I-type granites.These middle Permian gneissic granites with arc affinity may represent an arc setting related to the NW subduction of the paleo-Tethys.The analyses reveal that granites with late Triassic ages(235-232 Myr)in the Xiaomei shear zone have the characteristics of A-type granites.The late Triassic extensional events on Hainan Island may be related to the subduction of the paleo-Pacific Plate beneath the East Asian continent.
基金funded by the Chinese Geological Survey Program(Grant Nos.DD20160035,DD20190047)the National Nonprofit Institute Research Grant of IGGE(AS2022P03)the Chinese Scholarship Council(File No.201606400032)Scholarship to Liu Yuheng。
文摘The Mesoproterozoic Baoban Group is the oldest basement in Hainan Island and has played an important role in Columbia(Nuna)supercontinent reconstructions.The Mesoproterozoic granitic intrusions in the Baoban Group are the most widely-exposed Precambrian magmatic rocks and are the key to understanding the tectonic settings of Hainan Island and its relationship with the South China Block and the Columbia supercontinent.New LA-ICP-MS zircon U-Pb dating on three mylonitic granite samples from the Tuwaishan and Baoban areas yield ages ranging from 1447 Ma to 1437 Ma,representing the absolute timing of the emplacement of the granitic intrusions.Combined with previously published geochronological data for rocks from the Baoban Group and regional mafic intrusions,it is concluded that the Baoban Group formed at 1460-1430 Ma,coeval with the emplacement of the granitic and mafic intrusions.New in-situ zircon LuHf isotope analyses for the three mylonitic granite samples yielded positiveε(t)values,ranging from+0.49 to+8.27,with model ages(T~C)ranging from 2181 Ma to 1687 Ma,suggesting that the granitic intrusions originated from a mixed source of Paleoproterozoic crust with juvenile crust.New zircon trace element data show characteristics of high Th/U values of 0.24-1.50,steep slopes from LREE to HREE and negative Pr,Eu anomalies with positive Ce,Sm anomalies,representing typical magmatic zircons formed in continental crust.Compared with available magmatic and detrital zircon ages from Precambrian rocks in the Cathaysia Block,Yangtze Block and western Laurentia,it is inferred that Hainan Island was separated from both the Cathaysia Block and the Yangtze Block,instead being connected with western Laurentia in the Columbia supercontinent.Considering the decreasing tendency of basin deposition time along the western margin of Laurentia,it is proposed that Hainan Island was located to the north or northwest of the Belt-Purcell Supergroup,along the western margin of Laurentia,during the breakup of the Columbia supercontinent.
基金The National Natural Science Foundation of China under contract Nos 41706096 and 41530962the Research Startup Project of Jiangsu Normal University under contract No.19XSRX006+2 种基金the Opening Foundation of Hainan Key Laboratory of Marine Geological Resources and Environment under contract No.HNHYDZZYHJKF005the High-level Talent Program of Basic and Applied Basic Research Programs(Field of Natural Science)in Hainan Province under contract No.2019RC349a project funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions。
文摘The relationship between storm activity and global warming remains uncertain.To better understand storm–climate relationships,coastal lagoon deposits are increasingly being investigated because they could provide high-resolution storm records long enough to cover past climate changes.However,site-specific sediment dynamics and high barriers may bias storm reconstructions.Here,we aimed to investigate these factors through the reconstruction of five distinct storm records(XCL-01,XC-03,XC-06,XC-07,XC-08)from different water depths in a lagoon with a high barrier(i.e.,Xincun Lagoon of Hainan Island).Sediment cores were characterized using high-resolution grain size and XRF measurements,to identify storm events.These data were coupled with a numerical simulation to obtain bed shear stress data with high-spatial resolution to better understand storm-induced sediment transport mechanisms.^(210) Pb dating and Pb pollution chronostratigraphic markers indicated that the chronology of the storm deposit sequences of the cores span the period between 117 a and 348 a.The grain size and XRF results indicated numerous,highly variable and short-duration fluctuations,suggesting that storm-induced coarse-grained sediments were deposited at these core sites.The inconsistent storm events recorded in these cores suggest that these sites have different preservation potentials for storm deposits.However,the consistence between storm sediment records and historical documents for Core XCL-01 indicates that high-barrier lagoons could provide long-term storm event records with high preservation potential.
基金The Fundamental Research Funds for the Central Universities under contract No.18lgzd07the Key Research Program of Frontier Science+1 种基金CAS under contract No.QYZDB-SSW-DQC013-1the National Natural Science Foundation of China under contract No.41976128。
文摘The diversity,community composition and 16 S rRNA gene abundance of bacterioplankton along a transect across an upwelling area off the eastern coast of Hainan Island(the Qiongdong upwelling)were investigated in August of 2016 using high throughput sequencing and quantitative PCR assay of 16 S rRNA genes.Compared with the offshore stations,the inner-shelf stations had higher bacterial gene abundance(up to 3 fold)and operational taxonomic unit richness,a result of the influence of upwelled and fresher waters.Overall,a majority of the reads were affiliated with Gammaproteobacteria(11%-74%)and Alphaproteobacteria(14%-43%).The structure of the bacterial community was significantly affected by salinity,dissolved oxygen,NO_(3)^(-) and NH_(4)^(+),which also defined the physicochemical features of the upwelled waters.Horizontally,the relative abundances and gene abundances of Rhodobacteraceae,SAR86,Cyanobacteria and Bacteroidetes in eutrophic zone decreased from the inner to outer shelves and slope,whereas Alteromonas,Vibrio and Oceanospirillaceae exhibited an opposite trend.This study stresses the riverine influence on the oceanographic condition and spatial variability of bacterioplankton diversity and distribution in the Qiongdong upwelling.
基金supported by the National Natural Science Foundation of China(Grant No.41975008)Key Laboratory of South China Sea Meteorological Disaster Prevention and Mitigation of Hainan Province(Grant No.SCSF201906)。
文摘This study reveals a significant positive connection between autumn non-tropical-cyclone heavy rainfall on Hainan Island and the intensity of Eastern Pacific(EP)El Ni?o events.That is,the amount of rainfall in super EP El Ni?o years is more than that in normal EP El Ni?o years.Comparing EP El Ni?o years of different intensities,the cooler sea surface temperature in the northwestern Pacific during super EP El Ni?o years stimulates a negative surface latent heat flux(LHF)anomaly and abnormal anticyclonic circulation at 850 hPa.Under these conditions,an abnormal zonal vertical circulation develops in the northern South China Sea once a positive LHF anomaly and abnormal cyclonic circulation(ACC)at 850hPa occur in the Beibu Gulf.The abnormal zonal vertical circulation further strengthens the ascending motion over Hainan Island,as the critical factor that leads to excessive rainfall.Further analysis shows that the positive LHF anomaly,which can be attributed to the increased latent heat transfer which resulted from the increased surface wind speed,is an important trigger for the ACC.However,the ACC is also the supplier of favorable moisture conditions because it intensifies vapor convergence over Hainan Island and meridionally transports moisture from the South China Sea to northeastern Hainan Island,thereby generating heavy rainfall.This paper emphasizes that the impact of El Ni?o events,especially super El Ni?o events,on rainfall over Hainan Island cannot be ignored,even if the traditional view is that frequent rainfall occurs mainly in La Ni?a years.
基金National Natural Science Foundation of China(41905096)Key Laboratory of South China Sea Meteorological Disaster Prevention and Mitigation of Hainan Province(SCSF202004)。
文摘This study investigates the roles of the boreal summer intraseasonal oscillation(BSISO)in the diurnal rainfall cycle over Hainan Island during the warm season(April-September)using 20-year satellite-based precipitation,ERA5 and the outgoing longwave radiation data with the phase composite analysis method.Results show that the spatial distributions of the hourly rainfall anomaly significantly change under the BSISO phases 1-8 while no clear variations are found on the daily and anomaly daily area-averaged rainfall over the island.During the BSISO phase 1,the rainfall anomaly distinctly increases in the morning over the southwest and late afternoon over the northeast of the island,while suppressed convection occurs in the early afternoon over the southwest area.Under this circumstance,strong low-level westerly winds bring abundant moisture into the island,which helps initiate the nocturnal-morning convection over the south coastal area,and drives the convergence region of sea breeze fronts to concentrate into the northwest.Opposite to Phase 1,an almost completely reversed diurnal cycle of rainfall anomaly is found in Phase 5,whereas a positive anomalous rainfall peak is observed in the early afternoon over the center while negative peaks are found in the morning and late afternoon over the southwest and northeast,owing to a strong low-level northeasterly anomaly flow,which causes relatively low moisture and enlarges a sea-breeze convergence area over the island.During Phase 8,strongest moisture is found over the island all through the day,which tends to produce highest rainfall in the afternoon with enhanced anomalous northerly.These results further indicate that multiscale interactions between the large-scale circulations and local land-sea breeze circulations play important roles in modulating diurnal precipitation cycles over the tropical island.
文摘Studies on the aerolite fragments from Baisha crater, Hainan Island prove that they belong to calcium-rich achondrite which are relicts of cratering meteorite of the Baisha crater.These flat-ball shaped aerolite fragments, size being 21cm×18.5cm×8.7cm, were found in a creek within the Baisha crater. This hard aerolite weigh 3.75 kg with a density of 3.46g/cm<sub>3</sub>. It is mantled by a 0.1-0.5cm thick ,brown shell and its fresh section is dark-grey. The aerolite is characterized by porphyritic texture and no spherulitic texture has been found. Microscopic examination, X-ray diffraction analysis and electronic probe
文摘Hainan Island is the second largest island inChina. It is situated on the Nanhai Sea(SouthChina Sea) and faces Guangdong Province acrossQiongzhou Strait (海峡).Hainan Province was established(建立)in 1988. It consists of HainanIsland, Xisha Islands, Zhongsha Islands, NanshaIslands and the vast sea areas around them.
基金Project supported by the United Nations Development Program (UNDP, No. CPR/96/:05) the Na- tional Key Basic Research Support Foundation (NKBRSF) of China (No. G1999011809).
文摘The actual and potential water erosion rates of soils with different land covers in Hainan Island, China,were estimated based on the universal soil loss equation (USLE) and a 1:200 000 Soils and Terrain Digital Database (SOTER) database, from which soil water erosion factors could be extracted. 92.8% of the whole island had a current erosion rate of lower than 500 t km-2 a-1. Soil erosion risk was considered to be high because of its abundant rainfall. Without vegetation cover, the potential soil erosion rate would be extremely high and 90.8% of the island would have a soil erosion rate higher than 2 500 t km-2 a-1. Relative erosion vulnerability of different soil zones, landform types, and lithological regions of the island was compared by introducing a relative erosion hazard parameter α. Cambosols developed from siltstone and mudstone in low hill regions were pinpointed as soils with the highest erosion risk in the island.
文摘During the past half century, the land utilization of Hainan Island has undergone a rapid development,but in the meanwhile, soil degradation occurs. Analysis on some basic data of the soil series collected frommore than 100 soil profiles at the end of the 1990s and beginning of this century, in combination with dataavailable, showed that soils there suffered significant decline in organic matter, experienced P and K deficiencywith soil K going on losing and undergone acidification with continuing trend. The current situation calls forstrategies to build up Hainan into an important province of sound ecology by restoring forests, to improvefood quality by implementing K supplement projects, to combat soil acidification by ameliorating the soils andgrowing leguminous crops and to ensure health of the people by developing dairy production and increasingthe daily Ca uptake by the people.
