[Objective] This study aimed to investigate influencing factors and variation trends of muscle p H in chickens after slaughter. [Method] Beijing You chickens and Lohmann brown chickens were reared under the same condi...[Objective] This study aimed to investigate influencing factors and variation trends of muscle p H in chickens after slaughter. [Method] Beijing You chickens and Lohmann brown chickens were reared under the same conditions and slaughtered at the age of 8, 16 and 20 weeks, respectively. At different time（15 min, 1, 4, 8,12, 24 and 48 h） after slaughter, p H value of breast muscles and leg muscles was measured. [Result] The results showed that muscle position, post-slaughter time,gender and week age were important factors influencing p H value, but the breed had little effect. Within 1 h after slaughter, p H value of breast muscles and leg muscles declined rapidly, which reached the minimum level at 12 h after slaughter,and then increased slowly. In addition, p H value of leg muscles exhibited higher decline and increase rates than that of breast muscles to some extent. [Conclusion]This study provided basis for breeding of chickens with excellent meat quality.展开更多
By using the ground climate observation data of Chengdu from 1951 to 2009,the time variation sequence of mean temperature,total rainfall,seasonal mean temperature and precipitation were studied.The results showed that...By using the ground climate observation data of Chengdu from 1951 to 2009,the time variation sequence of mean temperature,total rainfall,seasonal mean temperature and precipitation were studied.The results showed that there was a trend of decreasing-increasing with the temperature and a trend of decreasing with the rainfall in Chengdu.The main temperature increasing occurred in spring and main rainfall decreasing occurred in summer.With the M-K method analysis,the spring temperature change time was in 1968,and the summer rainfall change time was in 1977 in Chengdu.With the temperature increasing in spring,the accumulated temperature would be higher,and it was beneficial to the agriculture.With the rainfall decreasing in summer,there was more summer drought.We needed to build more water facilities to protect agriculture production in Chengdu.展开更多
[Objective] Water quality variation trend of Wei River was analyzed and the water quality evaluation was performed in this study. [Method] Stationing and water sampling were conducted along Wei River at three differen...[Objective] Water quality variation trend of Wei River was analyzed and the water quality evaluation was performed in this study. [Method] Stationing and water sampling were conducted along Wei River at three different sites during the 12 months from January to December of 2014, the water samples were pre-treated and analyzed on chemical pollution indexes with the national standard, water quality data of Wei River in the 12 months was processed with periodic time series method, Spearman rank correlation coefficient was adopted to test pollution changing trend, and water quality status of Wei water was evaluated with integrated index of organic pollution. [Result] NH3-N and TN of Wei River exceeded the standard＇s lim- its; [ Y~ [ 〉Wp=0.506, [ Yss~ [ 〉Wp=0.506 and [ Y＆=0~,, Diecqieo 〉Wp=0.506 indicated that the integrated index of organic pollution of Shawangdu section, S.huyuan section and Tongguan Diaoqiao section showed a significant downtrend, respetively; and the water quality of the three sections became better, and it was worth noting that it was necessary to strengthen the water quality control of Wei River from January to June, so as to ensure that the water quality of Wei River reached the standard all the time. [Cendasien] This research was of significance in improving water ecological environment in Weinan as well as rationally utilizing water resources and finally realizing permanent development. Key words Wei River; Water quality variation trend; Integrated index of organic pollution; Evaluation展开更多
Evaporation, which is an important factor in the water balance at the basin scale, is a critical variable in the determination of local available water resources. Since the potential evaporation is mainly influenced b...Evaporation, which is an important factor in the water balance at the basin scale, is a critical variable in the determination of local available water resources. Since the potential evaporation is mainly influenced by meteorological variables, it is necessary to investigate the extent to which different meteorological variables affect the potential evaporation. The aim of this study was to explore the variation trends of different meteorological variables, and their impacts on the potential evaporation. This study selected the Hailar Meteorological Station of the Hailar region, which is situated in a cold, semi-arid, and sub-humid region, as a case study site. Based on observed daily meteorological data from 1951 to 2009, the potential evaporation was calculated with the Penman formula, and the variations of meteorological variables were investigated with the nonparametric Mann-Kendall test. The correlation between the potential evaporation and each meteorological variable at annual and seasonal scales was also analyzed. The results show that the annual and seasonal potential evaporation and air temperature present increasing trends, whereas the wind speed, sunshine duration, and relative humidity present decreasing trends. Among the meteorological variables, the air temperature and relative humidity are the key factors that affect potential evaporation at different time scales, and the impacts of other meteorological variables on the potential evaporation are not significant and vary with time scales.展开更多
To reveal the multivariate relationships between man-made and meteorological factors on dust storm frequency, the LUCC data, NDVI remote sensing data and meteorological data for the period of 1983-2013 were combined w...To reveal the multivariate relationships between man-made and meteorological factors on dust storm frequency, the LUCC data, NDVI remote sensing data and meteorological data for the period of 1983-2013 were combined with dust storm frequency data, and the possible impacts of meteorological and anthropogenic factors on dust storm frequency were analyzed by using regression analysis and PCA (Principal Component Analysis). Results show that the inter-annual dust storm frequency increased gradually. In particular, an increasing trend in recent years, after 2009, is conspicuous. The monthly frequency of dust storms shows higher values between the months of February and May, with the highest mean number of events occurring in April, which accounts for 29% of the annual dust storm frequency. The annual dust storm frequency is positively correlated with wind speed and negatively correlated with precipitation;the monthly dust storm frequency is positively correlated with wind speed, but no significant correlation can be found with precipitation. The relationship between temperature and dust storms is not simply linear, however, a certain correlation with an unremarkable statistical significance can be found between them. Human activities also affect the dynamics of dust storms indirectly via changing vegetation coverage and direct dust emissions. The multivariate analysis further confirmed the association between dust storm frequency and meteorological factors and NDVI. The high loadings of dust storm frequency, wind speed, precipitation and NDVI on a PC indicate that the increased precipitation and NDVI will decrease dust storm frequency, and increased wind speed will increase dust storm frequency.展开更多
This study analyzes the status-quo of the proved oil/gas initially-in-place and its variation trend,the proved undeveloped oil/gas initially-in-place,and the remaining proved technically recoverable reserves(TRR)of oi...This study analyzes the status-quo of the proved oil/gas initially-in-place and its variation trend,the proved undeveloped oil/gas initially-in-place,and the remaining proved technically recoverable reserves(TRR)of oil/gas in China as of 2020 based on statistics.As shown by the results,the proved oil initially-in-place(OIIP),the proved undeveloped OIIP,and the remaining proved TRR of oil in China are mainly distributed in the Bohai Bay,Ordos and Songliao Basins,and those of free gas are mainly in the Ordos,Sichuan,and Tarim Basins.From 2011 to 2020,the largest increment in the proved OIIP,the proved undeveloped OIIP and the remaining proved TRR of oil occurred in the Ordos Basin,followed by the Bohai Bay Basin,while that in the proved gas initially-in-place(GIIP),the proved undeveloped GIIP,and the remaining proved TRR of gas occurred in the Ordos Basin,followed by the Sichuan Basin.In addition,a comprehensive analysis reveals that the petroliferous basins in China with the potential of reserve addition and production growth include the Ordos Basin,the Bohai Bay Basin,the Sichuan Basin,and the Tarim Basin.展开更多
Based on meteorological data collected over nearly 60 years(1960-2017)from four national meteorological stations along the margins of the Badain Jaran Desert,this study analyzed the spatiotemporal variations in evapor...Based on meteorological data collected over nearly 60 years(1960-2017)from four national meteorological stations along the margins of the Badain Jaran Desert,this study analyzed the spatiotemporal variations in evaporation from water surfaces and identified the dominant controlling factors.Methods used included linear trend analysis,linear tendency estimation,the departure method,the rank correlation coefficient-based method,and Multiple Linear Regression(MLR).Results indicate notable spatiotemporal differences in evaporation distribution and evolution.Spatially,average annual evaporation exhibited a pronounced altitude effect,decreasing at a rate of about 8.23 mm/m from east to west with increasing altitude.Temporally,annual evaporation showed significant upward trends after 1996 at the northeastern(Guaizi Lake)and western(Dingxin)margins,with rates of 132 mm/10a and 105 mm/10a,respectively.Conversely,along the northwestern(Ejina Banner)and southern(Alxa Right Banner)margins of the desert,an evaporation paradox was observed,with annual evaporation trending downward at rates of 162 mm/10a and 187 mm/10a,respectively,especially after 1987.The dominant factors controlling evaporation varied spatially:Average annual temperature and relative humidity influended the western margin(Dingxin),average annual temperature was the key factor for the northeastern margin(Guaizi Lake),and average wind speed was crucial for the northern(Ejina Banner)and southern(Alxa Right Banner)margins.展开更多
Linear regression,climate trend rate,integral humidity indicator and dry-wet index were adopted to analyze the precipitation change,drought or waterlogging frequency and occurrence period in Benxi of Liaoning.The resu...Linear regression,climate trend rate,integral humidity indicator and dry-wet index were adopted to analyze the precipitation change,drought or waterlogging frequency and occurrence period in Benxi of Liaoning.The results showed that in recent 55 years,the tendency rate of annual precipitation in Benxi was-30.749 mm/10 a,reducing 165 mm in trend;the precipitation tendency rate during the growing season of plants was-31.371/10 a,reducing 173 mm in trend.The climate type was changed from light flood 20 a ago to wet type.The satisfaction of agriculture-required water was above 150% and annual average precipitation surplus was 290 mm.Benxi was hit by the medium floods to heavy floods in 10 years,about once in five years.The occurrence period of mild drought was 5 a,about once in ten years.The drought in spring below the medium degree occurred twice in a decade while the waterlogging above the medium degree occurred once in a decade.The waterlogging in summer above the medium degree occurred once in two years.The waterlogging in autumn above the medium degree occurred twice in a decade while the drought below the medium degree occurred four times in a decade.The occurrence frequency of heavy waterlogging in July and August was 54.5%.May and September were the period of time with a strikingly higher prevalence in drought.展开更多
The meteorological data of light,temperature and water during 1961-2009 were selected to analyze the trend variation of climatic resources and provide the basis for developing and utilizing local climate resources.The...The meteorological data of light,temperature and water during 1961-2009 were selected to analyze the trend variation of climatic resources and provide the basis for developing and utilizing local climate resources.The results indicated that light resource presented the decreasing tendency in Dongling District,annual radiation reduced by 528 MJ/m2,and annual sunshine duration decreased by 333 h.The heat resource presented the increasing tendency,the average annual temperature increased by 1.04 ℃,and active accumulated temperature increased by 228 ℃.The general trend of annual precipitation declined slightly,precipitation resource during every age changed slightly and would tend to be stable.展开更多
Taking the Lhasa River Basin above Lhasa hydrological station in Tibetan Plateau as a study area, the characteristics of the annual and monthly mean runoff during 1956-2003 were analyzed, based on the hydro-data of th...Taking the Lhasa River Basin above Lhasa hydrological station in Tibetan Plateau as a study area, the characteristics of the annual and monthly mean runoff during 1956-2003 were analyzed, based on the hydro-data of the two hydrological stations （Lhasa and Tanggya） and the meteorological data of the three meteorological stations （Damxung, Lhasa and Tanggya）. The trends and the change points of runoff and climate from 1956 to 2003 were detected using the nonparametric Mann-Kendall test and Pettitt-Mann-Whitney change-point statistics. The correlations between runoff and climate change were analyzed using multiple linear regression. The major results could be summarized as follows： （1） The annual mean runoff during the last 50 years is characterized by a great fluctuation and a positive trend with two change points （around 1970 and the early 1980s）, after which the runoff tended to increase and was increasing intensively in the last 20 years. Besides, the monthly mean runoff with a positive trend is centralized in winter half-year （November to April） and some other months （May, July and September）. （2） The trends of the climate change in the study area are generally consistent with the trend of the runoff, but the leading climate factors which aroused the runoff variation are distinct. Precipitation is the dominant factor influencing the annual and monthly mean runoff in summer half year, while temperature is the primary factor in winter season.展开更多
[Objective] This study aimed to analyze the characteristics of temperature variation in Zhangqiu City during the past 30 years. [Method] Variation characteristics of average annual maximum temperature, average annual ...[Objective] This study aimed to analyze the characteristics of temperature variation in Zhangqiu City during the past 30 years. [Method] Variation characteristics of average annual maximum temperature, average annual temperature and average annual minimum temperature in Zhangqiu City during the past 30 years were analyzed by using related temperature data during 1981 -2010 collected from National Meteorological Observation Station in Zhangqiu. [Result] Average annual maximum temperature, average annual temperature and average annual minimum temperature in Zhangqiu City showed an upward trend; average annual minimum temperature showed the most significant increasing tendency, with a tendency rate of 1.347 ℃/10 a; followed by average annual temperature; average annual maximum temperature showed the slowest increasing tendency, with a tendency rate of 0.062 ℃/10 a, indicating that the increase of average annual temperature mainly depended on the contribution of average annual minimum temperature. [Conclusion] This study provides reference and scientific basis for climate change monitoring, diagnosis, assessment, forecast and decision-making in Zhangqiu City.展开更多
According to the national standard(2006)on tropical cyclone(TC)intensity,TCs are categorized into six intensity types,namely,tropical depression(TD),tropical storm(TS),severe tropical storm(STS), typhoon(TY),severe ty...According to the national standard(2006)on tropical cyclone(TC)intensity,TCs are categorized into six intensity types,namely,tropical depression(TD),tropical storm(TS),severe tropical storm(STS), typhoon(TY),severe typhoon(STY),and super severe typhoon(SSTY).Fifty-eight years(1949–2006)of the datasets from the Yearbook of Typhoons and Yearbook of Tropical Cyclones were used to study the variation characteristics of TCs making landfalls in China's Mainland,Hainan and Taiwan islands.The main results are as follows.First,interannual or interdecadal variations in the number of landfalling TCs at different intensities exist.As far as long-term trends are concerned,the TD and TS frequencies show a significant linearly decreasing trend while those of STY show a significant linearly increasing trend.Second, a significant period of 6–8 years exist in the variations of annual landfalling TD,TS,and STS frequencies while quasi-16-year periods are found in the annual TY frequency.Third,TD and TS are generated mostly over the South China Sea,while TY,STY,and SSTY mostly over the waters southeast of the Bashi Channel and the ocean to the east of the Philippines.Fourth,as far as interdecadal trends are concerned,the frequencies of landfalling TD and TS generated over the South China Sea show significant linearly decreasing trends.However,TY and STY show significant linearly increasing trends.展开更多
[Objective] The research aimed to study the climate variation characteristics of frost in Shandong Province. [Method] The daily minimum surface temperature ≤ 0 ℃ in autumn or spring was as the frost index. Based on ...[Objective] The research aimed to study the climate variation characteristics of frost in Shandong Province. [Method] The daily minimum surface temperature ≤ 0 ℃ in autumn or spring was as the frost index. Based on the daily minimum surface temperature data in 67 meteorological observatories of Shandong Province during 1961-2008, the variation characteristics of first, last frost dates and frost-free period in Shandong Province were analyzed by using the climate diagnosis analysis method. [Result] The climate characteristics of first, last frost dates and frost-free period had the obvious geographical differences in Shandong Province in recent 48 years. The extreme differences of first, last frost dates and frost-free period were all above the three times of their standard deviations. It illustrated that the dispersion degrees of first, last dates and frost-free period were all very big. The average first frost date postponed with 1.99 d/10 a velocity in Shandong Province in recent 48 years, and the last frost date advanced with 1.46 d/10 a velocity. The postponing range of first frost date was bigger than the advancing range of last frost date, and the frost-free period prolonged with 3.42 d/10 a velocity. Seen from the interdecadal variations, the first frost date started to obviously postpone, and the last frost date obviously advanced since the 1990s. The frost-free period also started to obviously prolong since the 1990s. [Conclusion] The research provided the certain reference for the predication, prevention of frost disaster and the structure adjustment of crops.展开更多
[Objective] The research aimed to study the variation of rainfall data from Guilin Weather Station during 1957-2007.[Method] Based on the daily rainfall data in Guilin during 1957-2007,the trend,period and mutation of...[Objective] The research aimed to study the variation of rainfall data from Guilin Weather Station during 1957-2007.[Method] Based on the daily rainfall data in Guilin during 1957-2007,the trend,period and mutation of precipitation in Guilin in 51 years were analyzed by using the trend analysis,wavelet analysis and Mann-Kendall non-parameter statistics test method.[Result] The rainfall in Guilin in 51 years presented the rising trend.The rainfall variation was same in the first,second and third quarters of most years,except in the individual year.The rainfall in the fourth quarter had the decrease trend,and the variation was obvious in each year.It illustrated that the rainfall variation in winter was very unstable and had the decrease trend in recent years.But as a whole,the variation of total rainfall in Guilin wasn’t obvious and had the rise trend.It illustrated that the climate variation in Guilin in 51 years wasn’t obvious.The wavelet analysis showed that the rainfall variation in Guilin had 15-year big period and the small period of 2-3 years.Mann-Kendall non-parameter statistics test showed that the mutation situation of total rainfall in Guilin in 51 years wasn’t obvious.But the mutation situations in the second and third quarters were more.The variation in recent 10 years was the most obvious.Maybe it was affected by the global climate variation.[Conclusion] The research provided the theory basis for analyzing the climate variation in Guilin.展开更多
Sea ice conditions in the Bohai Sea of China are sensitive to large-scale climatic variations. On the basis of CLARA-A1-SAL data, the albedo variations are examined in space and time in the winter（December, January a...Sea ice conditions in the Bohai Sea of China are sensitive to large-scale climatic variations. On the basis of CLARA-A1-SAL data, the albedo variations are examined in space and time in the winter（December, January and February） from 1992 to 2008 in the Bohai Sea sea ice region. Time series data of the sea ice concentration（SIC）, the sea ice extent（SIE） and the sea surface temperature（SST） are used to analyze their relationship with the albedo. The sea ice albedo changed in volatility appears along with time, the trend is not obvious and increases very slightly during the study period at a rate of 0.388% per decade over the Bohai Sea sea ice region.The interannual variation is between 9.93% and 14.50%, and the average albedo is 11.79%. The sea ice albedo in years with heavy sea ice coverage, 1999, 2000 and 2005, is significantly higher than that in other years; in years with light sea ice coverage, 1994, 1998, 2001 and 2006, has low values. For the monthly albedo, the increasing trend（at a rate of 0.988% per decade） in December is distinctly higher than that in January and February. The mean albedo in January（12.90%） is also distinctly higher than that in the other two months. The albedo is significantly positively correlated with the SIC and is significantly negatively correlated with the SST（significance level 90%）.展开更多
By using the daily temperature data in 90 meteorological observatories in Shandong Province,the median and a new kind of extreme event detection method which was put forward by Hample,the variation characteristics of ...By using the daily temperature data in 90 meteorological observatories in Shandong Province,the median and a new kind of extreme event detection method which was put forward by Hample,the variation characteristics of extreme cold and warm weather climate events in Shandong Province were detected and analyzed.The results showed that the extreme high temperature days had no obvious variation,and the extreme warm days tended to increase.The extreme cold event decreased obviously and had the obvious inter-decadal variation characteristic.In the 1960s,the extreme cold(warm) event happened frequently,but they both decreased slightly during the 1970s-metaphase of 1980s.After the metaphase of 1990s,the extreme warm event happened frequently,but the extreme cold event decreased sharply.In the spatial distribution,the extreme cold events in most areas of Shandong tended to decrease.But the occurrence frequency variation of extreme warm event presented the radial distribution characteristics that it increased in the eastern coastal zone and decreased in the southwest,northwest of Shandong Province.Under the background that the global climate became warm obviously in the metaphase of 1980s,the positive trend scope of extreme warm event linear variation in Shandong Province obviously became large.The variation of extreme low temperature days in most areas tended to be stable,and the main trend of extreme cold days was still the rapid decrease.展开更多
A land surface model driven by the continuous three-year observed meteorological data with a time interval of 30 minutes at the Tongyu station, a reference site of the Coordinated Enhanced Observing Period （CEOP）, w...A land surface model driven by the continuous three-year observed meteorological data with a time interval of 30 minutes at the Tongyu station, a reference site of the Coordinated Enhanced Observing Period （CEOP）, was used to evaluate the observation bias of soil moisture （SM） data and analyze the variation of SM at different time scales. The saline-alkaline soil of the grassland at the Tongyu site makes the measured SM too high, especially in boreal summer of 2003-05. The simulated annual mean SM has the lowest value in 2004 and its three-year variation corresponds to the change of precipitation, whereas the observation shows the increasing trend from 2003 to 2005. Compared to the variation range between -60% and 40% for the anomaly percentage of the simulated daily mean SM during May-October of 2004, the measured data show the higher values more than 40%. The magnitude of the variation trend of the observed daily mean SM in 2003 and 2005 is generally consistent with the simulation. The largest deficiency for the soil moisture observation of the grassland is the overestimated value in the drought year with less precipitation. The simulated monthly mean SM has the lowest value in March due to the large contribution of evaporation relative to precipitation and this phenomenon can not be reproduced in the observation.展开更多
[Objective] The research aimed to study the climatic characteristics of hail in the southern mountain area of Ningxia in recent 50 years. [Method] Based on the hail observation data of 5 surface meteorological station...[Objective] The research aimed to study the climatic characteristics of hail in the southern mountain area of Ningxia in recent 50 years. [Method] Based on the hail observation data of 5 surface meteorological stations (Guyuan, Xiji, Jingyuan, Longde, Liupanshan) in the south of Ningxia during 1960-2009, the spatial distribution rule, the interannual and monthly climatic characteristics and variation trends of hail in the south mountain area of Ningxia were analyzed by using the statistical method. Moreover, the hail disaster prevention and reduction measures in Guyuan were put forward. [Result] The hail in the south mountain area of Ningxia in recent 50 years had the obvious annual, seasonal, monthly and daily variation characteristics. The hail might occur from March to October and mainly concentrated during May-August which occupied 72% in the whole year. The occurrence probability of hail in June was the biggest and occupied 21.7% in the whole year. It was the typical multi-hail zone in summer. The interannual variation of hail occurrence in Guyuan was big and had 3-year periodicity. The secondary-order time trend of hail in Guyuan was the anti-parabolic type, and the hail occurrence times during the 1960s-1980s presented the increase trend. It was the hail multi-occurrence period in the 1970s and 1980s. After the 1990s, the hail presented the decrease trend. In recent 20 years, the hail significantly decreased. The hail in Guyuan mainly concentrated during 12:00-21:00, and the hail occurrence times occupied 85% of total times. The hail distribution in Guyuan area had the obvious regional characteristics. The hail in the mountain area, hilly area was more and in the stream valley, north Pingchuan area was less. The hail cloud mainly derived from the mountain areas, such as Liupanshan, Nanhua Mountain, Yueliang Mountain, Xifeng Mountain and Yunwu Mountain, etc. The move direction of hail cloud was mainly from northwest to southeast or from north to south. Part of hail cloud disappeared in the original place. According to the regional distribution of hail, the hail risk in Guyuan City was divided into the high, moderate and low occurrence zones by combining with the hail disaster data. [Conclusion] The research provided the scientific basis for the forecast, early-warning of hail weather and the artificial hail suppression.展开更多
The active layer thickness(ALT)in permafrost regions,which affects water and energy exchange,is a key variable for assessing hydrological processes,cold-region engineering,and climate change.In this study,the authors ...The active layer thickness(ALT)in permafrost regions,which affects water and energy exchange,is a key variable for assessing hydrological processes,cold-region engineering,and climate change.In this study,the authors analyzed the variation trends and relative changes of simulated ALTs using the Chinese Academy of Sciences Land Surface Model(CAS-LSM)and the Chinese Academy of Sciences Flexible Global Ocean-Atmosphere-Land System Model,gridpoint version 3(CAS-FGOALS-g3).Firstly,the simulated ALTs produced by CAS-LSM were shown to be reasonable by comparing them with Circumpolar Active Layer Monitoring observations.Then,the authors simulated the ALTs from 1979 to 2014,and their relative changes across the entire Northern Hemisphere from 2015 to 2100.It is shown that the ALTs have an increasing trend.From 1979 to 2014,the average ALTs and their variation trends over all permafrost regions were 1.08 m and 0.33 cm yr-1,respectively.The relative changes of the ALTs ranged from 1%to 58%,and the average relative change was 10.9%.The variation trends of the ALTs were basically consistent with the variation trends of the 2-m air temperature.By 2100,the relative changes of ALTs are predicted to be 10.3%,14.6%,30.1%,and 51%,respectively,under the four considered hypothetical climate scenarios(SSP-2.6,SSP2-4.5,SSP3-7.0,and SSP5-8.5).This study indicates that climate change has a substantial impact on ALTs,and our results can help in understanding the responses of the ALTs of permafrost due to climate change.展开更多
On the basis of analyzing observational data on solar radiation, meteorological parameters, and total ozone amount for the period of January 1990 to December 1991 in the Beijing area, an empirical calculation method f...On the basis of analyzing observational data on solar radiation, meteorological parameters, and total ozone amount for the period of January 1990 to December 1991 in the Beijing area, an empirical calculation method for ultraviolet radiation (UV) in clear sky is obtained. The results show that the calculated values agree well with the observed, with maximum relative bias of 6.2% and mean relative bias for 24 months of 1.9%. Good results are also obtained when this method is applied in Guangzhou and Mohe districts. The long-term variation of UV radiation in clear sky over the Beijing area from 1979 to 1998 is calculated, and the UV variation trends and causes are discussed: direct and indirect UV energy absorption by increasing pollutants in the troposphere may have caused the UV decrease in clear sky in the last 20 years. With the enhancement of people's quality of life and awareness of health, it will be valuable and practical to provid UV forecasts for typical cities and rural areas. So, we should develop and enhance UV study in systematic monitoring, forecasting, and developing a good and feasible method for UV radiation reporting in China, especially for big cities.展开更多
基金Supported by Special Fund for the Construction of Modern Agricultural Industry Technology System(nycytx-42-Z02)Special Fund for Science,Technology and Innovation Capacity Building of Beijing Academy of Agriculture and Forestry Sciences(KJCX20140105)Youth Science Fund Project of National Natural Science Foundation of China(31001004)~~
文摘[Objective] This study aimed to investigate influencing factors and variation trends of muscle p H in chickens after slaughter. [Method] Beijing You chickens and Lohmann brown chickens were reared under the same conditions and slaughtered at the age of 8, 16 and 20 weeks, respectively. At different time（15 min, 1, 4, 8,12, 24 and 48 h） after slaughter, p H value of breast muscles and leg muscles was measured. [Result] The results showed that muscle position, post-slaughter time,gender and week age were important factors influencing p H value, but the breed had little effect. Within 1 h after slaughter, p H value of breast muscles and leg muscles declined rapidly, which reached the minimum level at 12 h after slaughter,and then increased slowly. In addition, p H value of leg muscles exhibited higher decline and increase rates than that of breast muscles to some extent. [Conclusion]This study provided basis for breeding of chickens with excellent meat quality.
文摘By using the ground climate observation data of Chengdu from 1951 to 2009,the time variation sequence of mean temperature,total rainfall,seasonal mean temperature and precipitation were studied.The results showed that there was a trend of decreasing-increasing with the temperature and a trend of decreasing with the rainfall in Chengdu.The main temperature increasing occurred in spring and main rainfall decreasing occurred in summer.With the M-K method analysis,the spring temperature change time was in 1968,and the summer rainfall change time was in 1977 in Chengdu.With the temperature increasing in spring,the accumulated temperature would be higher,and it was beneficial to the agriculture.With the rainfall decreasing in summer,there was more summer drought.We needed to build more water facilities to protect agriculture production in Chengdu.
基金Supported by Natural Science Foundation of China(41171061)Technological Innovation Support Fund of Weinan city(2012KYJ-3)Characteristic Discipline Construction Project of Weinan Normal University(14TSXK04,14TSXK05)~~
文摘[Objective] Water quality variation trend of Wei River was analyzed and the water quality evaluation was performed in this study. [Method] Stationing and water sampling were conducted along Wei River at three different sites during the 12 months from January to December of 2014, the water samples were pre-treated and analyzed on chemical pollution indexes with the national standard, water quality data of Wei River in the 12 months was processed with periodic time series method, Spearman rank correlation coefficient was adopted to test pollution changing trend, and water quality status of Wei water was evaluated with integrated index of organic pollution. [Result] NH3-N and TN of Wei River exceeded the standard＇s lim- its; [ Y~ [ 〉Wp=0.506, [ Yss~ [ 〉Wp=0.506 and [ Y＆=0~,, Diecqieo 〉Wp=0.506 indicated that the integrated index of organic pollution of Shawangdu section, S.huyuan section and Tongguan Diaoqiao section showed a significant downtrend, respetively; and the water quality of the three sections became better, and it was worth noting that it was necessary to strengthen the water quality control of Wei River from January to June, so as to ensure that the water quality of Wei River reached the standard all the time. [Cendasien] This research was of significance in improving water ecological environment in Weinan as well as rationally utilizing water resources and finally realizing permanent development. Key words Wei River; Water quality variation trend; Integrated index of organic pollution; Evaluation
基金supported by the Special Fund for Public Welfare Industry of Ministry of Water Resources of China(Grant No200901045)the Program for Changjiang Scholars and Innovative Research Team in University(Grant NoIRT0717)the 111 Project(Grant NoB08048)
文摘Evaporation, which is an important factor in the water balance at the basin scale, is a critical variable in the determination of local available water resources. Since the potential evaporation is mainly influenced by meteorological variables, it is necessary to investigate the extent to which different meteorological variables affect the potential evaporation. The aim of this study was to explore the variation trends of different meteorological variables, and their impacts on the potential evaporation. This study selected the Hailar Meteorological Station of the Hailar region, which is situated in a cold, semi-arid, and sub-humid region, as a case study site. Based on observed daily meteorological data from 1951 to 2009, the potential evaporation was calculated with the Penman formula, and the variations of meteorological variables were investigated with the nonparametric Mann-Kendall test. The correlation between the potential evaporation and each meteorological variable at annual and seasonal scales was also analyzed. The results show that the annual and seasonal potential evaporation and air temperature present increasing trends, whereas the wind speed, sunshine duration, and relative humidity present decreasing trends. Among the meteorological variables, the air temperature and relative humidity are the key factors that affect potential evaporation at different time scales, and the impacts of other meteorological variables on the potential evaporation are not significant and vary with time scales.
文摘To reveal the multivariate relationships between man-made and meteorological factors on dust storm frequency, the LUCC data, NDVI remote sensing data and meteorological data for the period of 1983-2013 were combined with dust storm frequency data, and the possible impacts of meteorological and anthropogenic factors on dust storm frequency were analyzed by using regression analysis and PCA (Principal Component Analysis). Results show that the inter-annual dust storm frequency increased gradually. In particular, an increasing trend in recent years, after 2009, is conspicuous. The monthly frequency of dust storms shows higher values between the months of February and May, with the highest mean number of events occurring in April, which accounts for 29% of the annual dust storm frequency. The annual dust storm frequency is positively correlated with wind speed and negatively correlated with precipitation;the monthly dust storm frequency is positively correlated with wind speed, but no significant correlation can be found with precipitation. The relationship between temperature and dust storms is not simply linear, however, a certain correlation with an unremarkable statistical significance can be found between them. Human activities also affect the dynamics of dust storms indirectly via changing vegetation coverage and direct dust emissions. The multivariate analysis further confirmed the association between dust storm frequency and meteorological factors and NDVI. The high loadings of dust storm frequency, wind speed, precipitation and NDVI on a PC indicate that the increased precipitation and NDVI will decrease dust storm frequency, and increased wind speed will increase dust storm frequency.
文摘This study analyzes the status-quo of the proved oil/gas initially-in-place and its variation trend,the proved undeveloped oil/gas initially-in-place,and the remaining proved technically recoverable reserves(TRR)of oil/gas in China as of 2020 based on statistics.As shown by the results,the proved oil initially-in-place(OIIP),the proved undeveloped OIIP,and the remaining proved TRR of oil in China are mainly distributed in the Bohai Bay,Ordos and Songliao Basins,and those of free gas are mainly in the Ordos,Sichuan,and Tarim Basins.From 2011 to 2020,the largest increment in the proved OIIP,the proved undeveloped OIIP and the remaining proved TRR of oil occurred in the Ordos Basin,followed by the Bohai Bay Basin,while that in the proved gas initially-in-place(GIIP),the proved undeveloped GIIP,and the remaining proved TRR of gas occurred in the Ordos Basin,followed by the Sichuan Basin.In addition,a comprehensive analysis reveals that the petroliferous basins in China with the potential of reserve addition and production growth include the Ordos Basin,the Bohai Bay Basin,the Sichuan Basin,and the Tarim Basin.
基金supported by the Natural Science Foundation of Hebei Province(D202450411)the Basic Research Programme of Chinese Academy of Geological Sciences(CAGS)(YK202302).
文摘Based on meteorological data collected over nearly 60 years(1960-2017)from four national meteorological stations along the margins of the Badain Jaran Desert,this study analyzed the spatiotemporal variations in evaporation from water surfaces and identified the dominant controlling factors.Methods used included linear trend analysis,linear tendency estimation,the departure method,the rank correlation coefficient-based method,and Multiple Linear Regression(MLR).Results indicate notable spatiotemporal differences in evaporation distribution and evolution.Spatially,average annual evaporation exhibited a pronounced altitude effect,decreasing at a rate of about 8.23 mm/m from east to west with increasing altitude.Temporally,annual evaporation showed significant upward trends after 1996 at the northeastern(Guaizi Lake)and western(Dingxin)margins,with rates of 132 mm/10a and 105 mm/10a,respectively.Conversely,along the northwestern(Ejina Banner)and southern(Alxa Right Banner)margins of the desert,an evaporation paradox was observed,with annual evaporation trending downward at rates of 162 mm/10a and 187 mm/10a,respectively,especially after 1987.The dominant factors controlling evaporation varied spatially:Average annual temperature and relative humidity influended the western margin(Dingxin),average annual temperature was the key factor for the northeastern margin(Guaizi Lake),and average wind speed was crucial for the northern(Ejina Banner)and southern(Alxa Right Banner)margins.
文摘Linear regression,climate trend rate,integral humidity indicator and dry-wet index were adopted to analyze the precipitation change,drought or waterlogging frequency and occurrence period in Benxi of Liaoning.The results showed that in recent 55 years,the tendency rate of annual precipitation in Benxi was-30.749 mm/10 a,reducing 165 mm in trend;the precipitation tendency rate during the growing season of plants was-31.371/10 a,reducing 173 mm in trend.The climate type was changed from light flood 20 a ago to wet type.The satisfaction of agriculture-required water was above 150% and annual average precipitation surplus was 290 mm.Benxi was hit by the medium floods to heavy floods in 10 years,about once in five years.The occurrence period of mild drought was 5 a,about once in ten years.The drought in spring below the medium degree occurred twice in a decade while the waterlogging above the medium degree occurred once in a decade.The waterlogging in summer above the medium degree occurred once in two years.The waterlogging in autumn above the medium degree occurred twice in a decade while the drought below the medium degree occurred four times in a decade.The occurrence frequency of heavy waterlogging in July and August was 54.5%.May and September were the period of time with a strikingly higher prevalence in drought.
文摘The meteorological data of light,temperature and water during 1961-2009 were selected to analyze the trend variation of climatic resources and provide the basis for developing and utilizing local climate resources.The results indicated that light resource presented the decreasing tendency in Dongling District,annual radiation reduced by 528 MJ/m2,and annual sunshine duration decreased by 333 h.The heat resource presented the increasing tendency,the average annual temperature increased by 1.04 ℃,and active accumulated temperature increased by 228 ℃.The general trend of annual precipitation declined slightly,precipitation resource during every age changed slightly and would tend to be stable.
基金National Basic Research Program of China, No.2005CB422006 National Natural Science Foundation of China, No.90202012 No.40561002
文摘Taking the Lhasa River Basin above Lhasa hydrological station in Tibetan Plateau as a study area, the characteristics of the annual and monthly mean runoff during 1956-2003 were analyzed, based on the hydro-data of the two hydrological stations （Lhasa and Tanggya） and the meteorological data of the three meteorological stations （Damxung, Lhasa and Tanggya）. The trends and the change points of runoff and climate from 1956 to 2003 were detected using the nonparametric Mann-Kendall test and Pettitt-Mann-Whitney change-point statistics. The correlations between runoff and climate change were analyzed using multiple linear regression. The major results could be summarized as follows： （1） The annual mean runoff during the last 50 years is characterized by a great fluctuation and a positive trend with two change points （around 1970 and the early 1980s）, after which the runoff tended to increase and was increasing intensively in the last 20 years. Besides, the monthly mean runoff with a positive trend is centralized in winter half-year （November to April） and some other months （May, July and September）. （2） The trends of the climate change in the study area are generally consistent with the trend of the runoff, but the leading climate factors which aroused the runoff variation are distinct. Precipitation is the dominant factor influencing the annual and monthly mean runoff in summer half year, while temperature is the primary factor in winter season.
文摘[Objective] This study aimed to analyze the characteristics of temperature variation in Zhangqiu City during the past 30 years. [Method] Variation characteristics of average annual maximum temperature, average annual temperature and average annual minimum temperature in Zhangqiu City during the past 30 years were analyzed by using related temperature data during 1981 -2010 collected from National Meteorological Observation Station in Zhangqiu. [Result] Average annual maximum temperature, average annual temperature and average annual minimum temperature in Zhangqiu City showed an upward trend; average annual minimum temperature showed the most significant increasing tendency, with a tendency rate of 1.347 ℃/10 a; followed by average annual temperature; average annual maximum temperature showed the slowest increasing tendency, with a tendency rate of 0.062 ℃/10 a, indicating that the increase of average annual temperature mainly depended on the contribution of average annual minimum temperature. [Conclusion] This study provides reference and scientific basis for climate change monitoring, diagnosis, assessment, forecast and decision-making in Zhangqiu City.
基金Natural Science Foundation of China(40765002)Public Interest Research Special Foundation(meteorology)of China(200906002)
文摘According to the national standard(2006)on tropical cyclone(TC)intensity,TCs are categorized into six intensity types,namely,tropical depression(TD),tropical storm(TS),severe tropical storm(STS), typhoon(TY),severe typhoon(STY),and super severe typhoon(SSTY).Fifty-eight years(1949–2006)of the datasets from the Yearbook of Typhoons and Yearbook of Tropical Cyclones were used to study the variation characteristics of TCs making landfalls in China's Mainland,Hainan and Taiwan islands.The main results are as follows.First,interannual or interdecadal variations in the number of landfalling TCs at different intensities exist.As far as long-term trends are concerned,the TD and TS frequencies show a significant linearly decreasing trend while those of STY show a significant linearly increasing trend.Second, a significant period of 6–8 years exist in the variations of annual landfalling TD,TS,and STS frequencies while quasi-16-year periods are found in the annual TY frequency.Third,TD and TS are generated mostly over the South China Sea,while TY,STY,and SSTY mostly over the waters southeast of the Bashi Channel and the ocean to the east of the Philippines.Fourth,as far as interdecadal trends are concerned,the frequencies of landfalling TD and TS generated over the South China Sea show significant linearly decreasing trends.However,TY and STY show significant linearly increasing trends.
文摘[Objective] The research aimed to study the climate variation characteristics of frost in Shandong Province. [Method] The daily minimum surface temperature ≤ 0 ℃ in autumn or spring was as the frost index. Based on the daily minimum surface temperature data in 67 meteorological observatories of Shandong Province during 1961-2008, the variation characteristics of first, last frost dates and frost-free period in Shandong Province were analyzed by using the climate diagnosis analysis method. [Result] The climate characteristics of first, last frost dates and frost-free period had the obvious geographical differences in Shandong Province in recent 48 years. The extreme differences of first, last frost dates and frost-free period were all above the three times of their standard deviations. It illustrated that the dispersion degrees of first, last dates and frost-free period were all very big. The average first frost date postponed with 1.99 d/10 a velocity in Shandong Province in recent 48 years, and the last frost date advanced with 1.46 d/10 a velocity. The postponing range of first frost date was bigger than the advancing range of last frost date, and the frost-free period prolonged with 3.42 d/10 a velocity. Seen from the interdecadal variations, the first frost date started to obviously postpone, and the last frost date obviously advanced since the 1990s. The frost-free period also started to obviously prolong since the 1990s. [Conclusion] The research provided the certain reference for the predication, prevention of frost disaster and the structure adjustment of crops.
基金Supported by Guangxi Scientific and Technological Project(Guikegong 0816006-10)Scientific Research Item of Guangxi Science and Technology Agency(Guikeneng 0801Z004)
文摘[Objective] The research aimed to study the variation of rainfall data from Guilin Weather Station during 1957-2007.[Method] Based on the daily rainfall data in Guilin during 1957-2007,the trend,period and mutation of precipitation in Guilin in 51 years were analyzed by using the trend analysis,wavelet analysis and Mann-Kendall non-parameter statistics test method.[Result] The rainfall in Guilin in 51 years presented the rising trend.The rainfall variation was same in the first,second and third quarters of most years,except in the individual year.The rainfall in the fourth quarter had the decrease trend,and the variation was obvious in each year.It illustrated that the rainfall variation in winter was very unstable and had the decrease trend in recent years.But as a whole,the variation of total rainfall in Guilin wasn’t obvious and had the rise trend.It illustrated that the climate variation in Guilin in 51 years wasn’t obvious.The wavelet analysis showed that the rainfall variation in Guilin had 15-year big period and the small period of 2-3 years.Mann-Kendall non-parameter statistics test showed that the mutation situation of total rainfall in Guilin in 51 years wasn’t obvious.But the mutation situations in the second and third quarters were more.The variation in recent 10 years was the most obvious.Maybe it was affected by the global climate variation.[Conclusion] The research provided the theory basis for analyzing the climate variation in Guilin.
文摘Sea ice conditions in the Bohai Sea of China are sensitive to large-scale climatic variations. On the basis of CLARA-A1-SAL data, the albedo variations are examined in space and time in the winter（December, January and February） from 1992 to 2008 in the Bohai Sea sea ice region. Time series data of the sea ice concentration（SIC）, the sea ice extent（SIE） and the sea surface temperature（SST） are used to analyze their relationship with the albedo. The sea ice albedo changed in volatility appears along with time, the trend is not obvious and increases very slightly during the study period at a rate of 0.388% per decade over the Bohai Sea sea ice region.The interannual variation is between 9.93% and 14.50%, and the average albedo is 11.79%. The sea ice albedo in years with heavy sea ice coverage, 1999, 2000 and 2005, is significantly higher than that in other years; in years with light sea ice coverage, 1994, 1998, 2001 and 2006, has low values. For the monthly albedo, the increasing trend（at a rate of 0.988% per decade） in December is distinctly higher than that in January and February. The mean albedo in January（12.90%） is also distinctly higher than that in the other two months. The albedo is significantly positively correlated with the SIC and is significantly negatively correlated with the SST（significance level 90%）.
文摘By using the daily temperature data in 90 meteorological observatories in Shandong Province,the median and a new kind of extreme event detection method which was put forward by Hample,the variation characteristics of extreme cold and warm weather climate events in Shandong Province were detected and analyzed.The results showed that the extreme high temperature days had no obvious variation,and the extreme warm days tended to increase.The extreme cold event decreased obviously and had the obvious inter-decadal variation characteristic.In the 1960s,the extreme cold(warm) event happened frequently,but they both decreased slightly during the 1970s-metaphase of 1980s.After the metaphase of 1990s,the extreme warm event happened frequently,but the extreme cold event decreased sharply.In the spatial distribution,the extreme cold events in most areas of Shandong tended to decrease.But the occurrence frequency variation of extreme warm event presented the radial distribution characteristics that it increased in the eastern coastal zone and decreased in the southwest,northwest of Shandong Province.Under the background that the global climate became warm obviously in the metaphase of 1980s,the positive trend scope of extreme warm event linear variation in Shandong Province obviously became large.The variation of extreme low temperature days in most areas tended to be stable,and the main trend of extreme cold days was still the rapid decrease.
基金the National Basic Research Program of China (Grant No. 2006CB400500)the Knowledge Innovation Program of the Chinese Academy of Sciences (Grant No. IAP 07114)the National Natural Science Foundation of China (Grant Nos. 40605025, 40730106)
文摘A land surface model driven by the continuous three-year observed meteorological data with a time interval of 30 minutes at the Tongyu station, a reference site of the Coordinated Enhanced Observing Period （CEOP）, was used to evaluate the observation bias of soil moisture （SM） data and analyze the variation of SM at different time scales. The saline-alkaline soil of the grassland at the Tongyu site makes the measured SM too high, especially in boreal summer of 2003-05. The simulated annual mean SM has the lowest value in 2004 and its three-year variation corresponds to the change of precipitation, whereas the observation shows the increasing trend from 2003 to 2005. Compared to the variation range between -60% and 40% for the anomaly percentage of the simulated daily mean SM during May-October of 2004, the measured data show the higher values more than 40%. The magnitude of the variation trend of the observed daily mean SM in 2003 and 2005 is generally consistent with the simulation. The largest deficiency for the soil moisture observation of the grassland is the overestimated value in the drought year with less precipitation. The simulated monthly mean SM has the lowest value in March due to the large contribution of evaporation relative to precipitation and this phenomenon can not be reproduced in the observation.
文摘[Objective] The research aimed to study the climatic characteristics of hail in the southern mountain area of Ningxia in recent 50 years. [Method] Based on the hail observation data of 5 surface meteorological stations (Guyuan, Xiji, Jingyuan, Longde, Liupanshan) in the south of Ningxia during 1960-2009, the spatial distribution rule, the interannual and monthly climatic characteristics and variation trends of hail in the south mountain area of Ningxia were analyzed by using the statistical method. Moreover, the hail disaster prevention and reduction measures in Guyuan were put forward. [Result] The hail in the south mountain area of Ningxia in recent 50 years had the obvious annual, seasonal, monthly and daily variation characteristics. The hail might occur from March to October and mainly concentrated during May-August which occupied 72% in the whole year. The occurrence probability of hail in June was the biggest and occupied 21.7% in the whole year. It was the typical multi-hail zone in summer. The interannual variation of hail occurrence in Guyuan was big and had 3-year periodicity. The secondary-order time trend of hail in Guyuan was the anti-parabolic type, and the hail occurrence times during the 1960s-1980s presented the increase trend. It was the hail multi-occurrence period in the 1970s and 1980s. After the 1990s, the hail presented the decrease trend. In recent 20 years, the hail significantly decreased. The hail in Guyuan mainly concentrated during 12:00-21:00, and the hail occurrence times occupied 85% of total times. The hail distribution in Guyuan area had the obvious regional characteristics. The hail in the mountain area, hilly area was more and in the stream valley, north Pingchuan area was less. The hail cloud mainly derived from the mountain areas, such as Liupanshan, Nanhua Mountain, Yueliang Mountain, Xifeng Mountain and Yunwu Mountain, etc. The move direction of hail cloud was mainly from northwest to southeast or from north to south. Part of hail cloud disappeared in the original place. According to the regional distribution of hail, the hail risk in Guyuan City was divided into the high, moderate and low occurrence zones by combining with the hail disaster data. [Conclusion] The research provided the scientific basis for the forecast, early-warning of hail weather and the artificial hail suppression.
基金supported by the National Key R&D Program of China[grant number 2018YFC1506602]the Key Research Program of Frontier Sciences,CAS[grant number QYZDY-SSW-DQC012]the National Natural Science Foundation of China[grant number 41830967]。
文摘The active layer thickness(ALT)in permafrost regions,which affects water and energy exchange,is a key variable for assessing hydrological processes,cold-region engineering,and climate change.In this study,the authors analyzed the variation trends and relative changes of simulated ALTs using the Chinese Academy of Sciences Land Surface Model(CAS-LSM)and the Chinese Academy of Sciences Flexible Global Ocean-Atmosphere-Land System Model,gridpoint version 3(CAS-FGOALS-g3).Firstly,the simulated ALTs produced by CAS-LSM were shown to be reasonable by comparing them with Circumpolar Active Layer Monitoring observations.Then,the authors simulated the ALTs from 1979 to 2014,and their relative changes across the entire Northern Hemisphere from 2015 to 2100.It is shown that the ALTs have an increasing trend.From 1979 to 2014,the average ALTs and their variation trends over all permafrost regions were 1.08 m and 0.33 cm yr-1,respectively.The relative changes of the ALTs ranged from 1%to 58%,and the average relative change was 10.9%.The variation trends of the ALTs were basically consistent with the variation trends of the 2-m air temperature.By 2100,the relative changes of ALTs are predicted to be 10.3%,14.6%,30.1%,and 51%,respectively,under the four considered hypothetical climate scenarios(SSP-2.6,SSP2-4.5,SSP3-7.0,and SSP5-8.5).This study indicates that climate change has a substantial impact on ALTs,and our results can help in understanding the responses of the ALTs of permafrost due to climate change.
基金supported by the National Natural Science Foundation of China(No.40175031).
文摘On the basis of analyzing observational data on solar radiation, meteorological parameters, and total ozone amount for the period of January 1990 to December 1991 in the Beijing area, an empirical calculation method for ultraviolet radiation (UV) in clear sky is obtained. The results show that the calculated values agree well with the observed, with maximum relative bias of 6.2% and mean relative bias for 24 months of 1.9%. Good results are also obtained when this method is applied in Guangzhou and Mohe districts. The long-term variation of UV radiation in clear sky over the Beijing area from 1979 to 1998 is calculated, and the UV variation trends and causes are discussed: direct and indirect UV energy absorption by increasing pollutants in the troposphere may have caused the UV decrease in clear sky in the last 20 years. With the enhancement of people's quality of life and awareness of health, it will be valuable and practical to provid UV forecasts for typical cities and rural areas. So, we should develop and enhance UV study in systematic monitoring, forecasting, and developing a good and feasible method for UV radiation reporting in China, especially for big cities.
