长江中下游地区气象干旱特征
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摘要
长江中下游地区是中国重要的粮食生产基地,在当前全球气候变化的背景下,旱灾将直接影响该区域人民的生产生活和国家粮食安全。基于标准化降水指数(SPI),采用1961-2015年的中国地面降水月值0.5°×0.5°格点数据集,通过游程理论定义气象干旱事件,并获取了描述干旱事件特征的三个变量:干旱历时、干旱烈度和烈度峰值。指数函数和伽马函数分别用来拟合干旱历时和干旱烈度的边缘分布,Clayton Copula函数用来构建干旱历时和干旱烈度的联合分布。在此基础上,分别用常规单变量和基于Copula双变量的频率分析方法探讨55年来长江中下游地区干旱事件在不同时间尺度下的空间特征。结果表明:(1)不同时间尺度下,长江中下游地区的干旱特征空间格局存在一定的差异,最严重的干旱主要发生在长江下游地区;(2)不同时间尺度的干旱历时和干旱烈度均呈正相关,即较严重的干旱事件通常持续更长的时间;(3)鄱阳湖流域和长江干流下游的北部干旱风险较高,而陕西南部、河南南部、湖北大部和湖南的中北部干旱风险较低。研究结果可为长江中下游地区水资源的科学管理和干旱灾害的风险评估提供理论依据。
The middle and lower reaches of the Yangtze River serves as an important grain production base in China. In the context of global climate change, the drought events will directly affect the agriculture production and people's properties and lives in this region and also the national food security. In this study, the meteorological drought events have been extracted using run theory based on the standardized precipitation index(SPI), which is defined using the gridded dataset of monthly precipitation with a spatial resolution of 0.5° × 0.5° in China from 1961 to 2015. The drought events are characterized by three variables including duration, severity and peak. Exponential and Gamma functions are then selected to describe the marginal distribution of drought duration and severity, respectively. The Clayton Copula is used to construct the joint distribution of drought duration and severity. Based on the above functions, conventional univariate frequency analysis and copula-based bivariate frequency analysis are used to characterize the spatial patterns of the drought events in the study area at various time scales over the past 55 years. While univariate analysis is focused on return levels of selected return periods(5-, 10-, 20-, and 30-year) for the SPI of 3-, 6-, and 12-month time scales, the bivariate analysis is focused on the joint occurrence probabilities P1 and P2 of drought duration and severity, where P1 is the probability of "drought duration and severity" exceeding their respective thresholds at the same time and P2 is the probability of "drought duration or severity" exceeding their respective thresholds at the same time. Here, the thresholds denote the duration and severity values corresponding to selected 5-, 10-, 20-and 30-year return periods. The results show that:(1) There are some differences between the spatial patterns of drought characteristics for the 3-month, 6-month, 12-month time scales in the middle and lower reaches of the Yangtze River, and the most serious droughts mainly occur in the lower reaches of the river.(2) Both drought duration and severity are positively correlated at various time scales, that is, the areas with higher drought severity are also associated with longer drought duration and vice versa.(3) Poyang Lake watershed and areas north of the lower Yangtze River are associated with larger values of the joint occurrence probability P1,that is, when the drought duration and severity exceed their corresponding 5, 10, 20 and 30-year return values at the same time, while smaller values of the joint occurrence probability P1 are noted for Southern Shaanxi, Southern Henan, a major portion of Hubei and central-north of Hunan, suggesting a low risk of droughts in these areas. The results of this study can provide theoretical basis for scientific managements of water resource and the risk assessments of drought disaster in the middle and lower reaches of the Yangtze River.
The middle and lower reaches of the Yangtze River serves as an important grain production base in China. In the context of global climate change, the drought events will directly affect the agriculture production and people's properties and lives in this region and also the national food security. In this study, the meteorological drought events have been extracted using run theory based on the standardized precipitation index(SPI), which is defined using the gridded dataset of monthly precipitation with a spatial resolution of 0.5° × 0.5° in China from 1961 to 2015. The drought events are characterized by three variables including duration, severity and peak. Exponential and Gamma functions are then selected to describe the marginal distribution of drought duration and severity, respectively. The Clayton Copula is used to construct the joint distribution of drought duration and severity. Based on the above functions, conventional univariate frequency analysis and copula-based bivariate frequency analysis are used to characterize the spatial patterns of the drought events in the study area at various time scales over the past 55 years. While univariate analysis is focused on return levels of selected return periods(5-, 10-, 20-, and 30-year) for the SPI of 3-, 6-, and 12-month time scales, the bivariate analysis is focused on the joint occurrence probabilities P1 and P2 of drought duration and severity, where P1 is the probability of "drought duration and severity" exceeding their respective thresholds at the same time and P2 is the probability of "drought duration or severity" exceeding their respective thresholds at the same time. Here, the thresholds denote the duration and severity values corresponding to selected 5-, 10-, 20-and 30-year return periods. The results show that:(1) There are some differences between the spatial patterns of drought characteristics for the 3-month, 6-month, 12-month time scales in the middle and lower reaches of the Yangtze River, and the most serious droughts mainly occur in the lower reaches of the river.(2) Both drought duration and severity are positively correlated at various time scales, that is, the areas with higher drought severity are also associated with longer drought duration and vice versa.(3) Poyang Lake watershed and areas north of the lower Yangtze River are associated with larger values of the joint occurrence probability P1,that is, when the drought duration and severity exceed their corresponding 5, 10, 20 and 30-year return values at the same time, while smaller values of the joint occurrence probability P1 are noted for Southern Shaanxi, Southern Henan, a major portion of Hubei and central-north of Hunan, suggesting a low risk of droughts in these areas. The results of this study can provide theoretical basis for scientific managements of water resource and the risk assessments of drought disaster in the middle and lower reaches of the Yangtze River.
引文
[1]张强,张良,崔显成,等.干旱监测与评价技术的发展及其科学挑战.地球科学进展,2011,26(7):763-778.[ZHANGQ,ZHANG L,CUI X C,et al.Progresses and challenges in drought assessment and monitoring.Advances in Earth Science,2011,26(7):763-778.]
[2]LIU C L,ZHANG Q,SINGH V P,et al.Copula-based evaluations of drought variations in Guangdong,South China.Natural Hazards,2011,59(3):1533-1546.
[3]周扬,李宁,吉中会,等.基于SPI指数的1981-2010年内蒙古地区干旱时空分布特征.自然资源学报,2013,28(10):1694-1706.[ZHOU Y,LI N,JI Z H,et al.Temporal and spatial patterns of droughts based on standard precipitation index(SPI)in Inner Mongolia during 1981-2010.Journal of Natural Resources,2013,28(10):1694-1706.]
[4]翟禄新,冯起.基于SPI的西北地区气候干湿变化.自然资源学报,2011,26(5):847-857.[ZHAI L X,FENG Q.Dryness/wetness climate variation based on standardized precipitation index in Northwest China.Journal of Natural Resources,2011,26(5):847-857.]
[5]吴贤云,丁一汇,王琪,等.近40年长江中游地区旱涝特点分析.应用气象学报,2006,17(1):19-28.[WU X Y,DINGY H,WANG Q,et al.Characteristics of the recent 40-year flood/drought over the middle reaches of the Yangtze.Journal of Applied Meteorological Science,2006,17(1):19-28.]
[6]柳艳香,赵振国,朱艳峰,等.2000年以来夏季长江流域降水异常研究.高原气象,2008,27(4):807-813.[LIU Y X,ZHAO Z G,ZHU Y F,et al.Research of JJA precipitation anomaly in Yangtze River Basin since 2000.Plateau Meteorology,2008,27(4):807-813.]
[7]王文,许志丽,蔡晓军,等.基于PDSI的长江中下游地区干旱分布特征.高原气象,2016,35(3):693-707.[WANG W,XU Z L,CAI X J,et al.Aridity characteristic in middle and lower reaches of Yangtze River area based on palmer drought severity index analysis.Plateau Meteorology,2016,35(3):693-707.]
[8]SKLAR A.Fonctions de répartitionàn dimensionset leurs marges.Publications de l'Institut de Statistique de L'Universitéde Paris,1959,8:229-231.
[9]李明,张永清,张莲芝.基于Copula函数的长春市106年来的干旱特征分析.干旱区资源与环境,2017,31(6):147-153.[LI M,ZHANG Y Q,ZHANG L Z.Analysis on drought characteristics of Changchun city in 106 years based on Copula function.Journal of Arid Land Resources and Environment,2017,31(6):147-153.]
[10]SHIAU J T.Fitting drought duration and severity with two-dimensional Copulas.Water Resources Management,2006,20(5):795-815.
[11]SHIAU J T,MODARRES R.Copula-based drought severity-duration-frequency analysis in Iran.Meteorological Applications,2009,16(4):481-489.
[12]闫宝伟,郭生练,肖义,等.基于两变量联合分布的干旱特征分析.干旱区研究,2007,24(4):537-542.[YAN B W,GUO S L,XIAO Y,et al.Analysis on drought characteristics based on bivariate joint distribution.Arid Zone Research,2007,24(4):537-542.]
[13]MIRABBASI R,FAKHERI-FARD A,DINPASHOH Y.Bivariate drought frequency analysis using the Copula method.Theoretical and Applied Climatology,2012,108(1-2):191-206.
[14]ZHANG D D,YAN D H,LU F,et al.Copula-based risk assessment of drought in Yunnan province,China.Natural Hazards,2015,75(3):2199-2220.
[15]陈再清,侯威,左冬冬,等.基于修订Copula函数的中国干旱特征研究.干旱气象,2016,34(2):213-222,268.[CHENZ Q,HOU W,ZUO D D,et al.Research on drought characteristics in China based on the revised Copula function.Journal of Arid Meteorology,2016,34(2):213-222,268.]
[16]LIU X F,WANG S X,ZHOU Y,et al.Spatial analysis of meteorological drought return periods in China using Copulas.Natural Hazards,2016,80(1):367-388.
[17]MASUD M,KHALIQ M,WHEATER H.Analysis of meteorological droughts for the Saskatchewan River Basin using univariate and bivariate approaches.Journal of Hydrology,2015,522:452-466.
[18]董蕾,张明军,王圣杰,等.基于格点数据的西北干旱区极端降水事件分析.自然资源学报,2014,29(12):2048-2057.[DONG L,ZHANG M J,WANG S J,et al.Extreme precipitation events in arid areas in Northwest China based on gridded data.Journal of Natural Resources,2014,29(12):2048-2057.]
[19]秦鹏程,刘敏.气象干旱诊断评估方法及其在长江中下游地区的应用.长江流域资源与环境,2015,24(11):1969-1976.[QIN P C,LIU M.Methods for diagnosis and assessment of meteorological drought and application in the middle and lower Yangtze Basin.Resources and Environment in the Yangtze Basin,2015,24(11):1969-1976.]
[20]赵煜飞,朱江,许艳.近50 a中国降水格点数据集的建立及质量评估.气象科学,2014,34(4):414-420.[ZHAO Y F,ZHU J,XU Y.Establishment and assessment of the grid precipitation datasets in China for recent 50 years.Journal of the Meteorological Sciences,2014,34(4):414-420.]
[21]MCKEE T B,DOESKEN N J,KLEIST J.The relationship of drought frequency and duration to time scales//Proceedings of the Eighth Conference on Applied Climatology.American Meteorological Society Boston,1993:179-184.
[22]张强,邹旭恺,肖风劲,等.气象干旱等级(GB/T 20481-2006).北京:中国标准出版社,2006:14-15.[ZHANG Q,ZOU X K,XIAO F J,et al.Classification of Meteorological Drought(GB/T 20481-2006).Beijing:Standard Press of China,2006:14-15.]
[23]KEYANTASH J,DRACUP J A.The quantification of drought:An evaluation of drought indices.Bulletin of the American Meteorological Society,2002,83(8):1167-1180.
[24]YEVJEVICH V M.An objective approach to definitions and investigations of continental hydrologic droughts.Hydrology Papers(No.23),Colorado State University,Fort Collins,1967.
[25]陈璐,郭生练,闫宝伟,等.基于Copula函数的干旱特征分析.水资源研究,2012,1(4):186-194.[CHEN L,GUO S L,YAN B W,et al.Drought characteristics analysis using Copulas.Journal of Water Resources Research,2012,1(4):186-194.]
[26]陆桂华,闫桂霞,吴志勇,等.基于Copula函数的区域干旱分析方法.水科学进展,2010,21(2):188-193.[LU G H,YAN G X,WU Z Y,et al.Regional drought analysis approach based on Copula function.Advances in Water Science,2010,21(2):188-193.]
[27]SHIAU J T,SHEN H W.Recurrence analysis of hydrologic droughts of differing severity.Journal of Water Resources Planning and Management,2001,127(1):30-40.
[28]左冬冬,侯威,颜鹏程,等.基于游程理论和两变量联合分布的中国西南地区干旱特征研究.物理学报,2014,63(23):45-56.[ZUO D D,HOU W,YAN P C,et al.Research on drought in Southwest China based on the theory of run and two-dimensional joint distribution theory.Acta Physica Sinica,2014,63(23):45-56.]
[29]肖名忠,张强,陈晓宏.基于多变量概率分析的珠江流域干旱特征研究.地理学报,2012,67(1):83-92.[XIAO M Z,ZHANG Q,CHEN X H.Spatial-temporal patterns of drought risk across the Pearl River Basin.Acta Geographica Sinica,2012,67(1):83-92.]
[30]XU K,YANG D W,XU X Y,et al.Copula based drought frequency analysis considering the spatio-temporal variability in Southwest China.Journal of Hydrology,2015,527:630-640.
[2]LIU C L,ZHANG Q,SINGH V P,et al.Copula-based evaluations of drought variations in Guangdong,South China.Natural Hazards,2011,59(3):1533-1546.
[3]周扬,李宁,吉中会,等.基于SPI指数的1981-2010年内蒙古地区干旱时空分布特征.自然资源学报,2013,28(10):1694-1706.[ZHOU Y,LI N,JI Z H,et al.Temporal and spatial patterns of droughts based on standard precipitation index(SPI)in Inner Mongolia during 1981-2010.Journal of Natural Resources,2013,28(10):1694-1706.]
[4]翟禄新,冯起.基于SPI的西北地区气候干湿变化.自然资源学报,2011,26(5):847-857.[ZHAI L X,FENG Q.Dryness/wetness climate variation based on standardized precipitation index in Northwest China.Journal of Natural Resources,2011,26(5):847-857.]
[5]吴贤云,丁一汇,王琪,等.近40年长江中游地区旱涝特点分析.应用气象学报,2006,17(1):19-28.[WU X Y,DINGY H,WANG Q,et al.Characteristics of the recent 40-year flood/drought over the middle reaches of the Yangtze.Journal of Applied Meteorological Science,2006,17(1):19-28.]
[6]柳艳香,赵振国,朱艳峰,等.2000年以来夏季长江流域降水异常研究.高原气象,2008,27(4):807-813.[LIU Y X,ZHAO Z G,ZHU Y F,et al.Research of JJA precipitation anomaly in Yangtze River Basin since 2000.Plateau Meteorology,2008,27(4):807-813.]
[7]王文,许志丽,蔡晓军,等.基于PDSI的长江中下游地区干旱分布特征.高原气象,2016,35(3):693-707.[WANG W,XU Z L,CAI X J,et al.Aridity characteristic in middle and lower reaches of Yangtze River area based on palmer drought severity index analysis.Plateau Meteorology,2016,35(3):693-707.]
[8]SKLAR A.Fonctions de répartitionàn dimensionset leurs marges.Publications de l'Institut de Statistique de L'Universitéde Paris,1959,8:229-231.
[9]李明,张永清,张莲芝.基于Copula函数的长春市106年来的干旱特征分析.干旱区资源与环境,2017,31(6):147-153.[LI M,ZHANG Y Q,ZHANG L Z.Analysis on drought characteristics of Changchun city in 106 years based on Copula function.Journal of Arid Land Resources and Environment,2017,31(6):147-153.]
[10]SHIAU J T.Fitting drought duration and severity with two-dimensional Copulas.Water Resources Management,2006,20(5):795-815.
[11]SHIAU J T,MODARRES R.Copula-based drought severity-duration-frequency analysis in Iran.Meteorological Applications,2009,16(4):481-489.
[12]闫宝伟,郭生练,肖义,等.基于两变量联合分布的干旱特征分析.干旱区研究,2007,24(4):537-542.[YAN B W,GUO S L,XIAO Y,et al.Analysis on drought characteristics based on bivariate joint distribution.Arid Zone Research,2007,24(4):537-542.]
[13]MIRABBASI R,FAKHERI-FARD A,DINPASHOH Y.Bivariate drought frequency analysis using the Copula method.Theoretical and Applied Climatology,2012,108(1-2):191-206.
[14]ZHANG D D,YAN D H,LU F,et al.Copula-based risk assessment of drought in Yunnan province,China.Natural Hazards,2015,75(3):2199-2220.
[15]陈再清,侯威,左冬冬,等.基于修订Copula函数的中国干旱特征研究.干旱气象,2016,34(2):213-222,268.[CHENZ Q,HOU W,ZUO D D,et al.Research on drought characteristics in China based on the revised Copula function.Journal of Arid Meteorology,2016,34(2):213-222,268.]
[16]LIU X F,WANG S X,ZHOU Y,et al.Spatial analysis of meteorological drought return periods in China using Copulas.Natural Hazards,2016,80(1):367-388.
[17]MASUD M,KHALIQ M,WHEATER H.Analysis of meteorological droughts for the Saskatchewan River Basin using univariate and bivariate approaches.Journal of Hydrology,2015,522:452-466.
[18]董蕾,张明军,王圣杰,等.基于格点数据的西北干旱区极端降水事件分析.自然资源学报,2014,29(12):2048-2057.[DONG L,ZHANG M J,WANG S J,et al.Extreme precipitation events in arid areas in Northwest China based on gridded data.Journal of Natural Resources,2014,29(12):2048-2057.]
[19]秦鹏程,刘敏.气象干旱诊断评估方法及其在长江中下游地区的应用.长江流域资源与环境,2015,24(11):1969-1976.[QIN P C,LIU M.Methods for diagnosis and assessment of meteorological drought and application in the middle and lower Yangtze Basin.Resources and Environment in the Yangtze Basin,2015,24(11):1969-1976.]
[20]赵煜飞,朱江,许艳.近50 a中国降水格点数据集的建立及质量评估.气象科学,2014,34(4):414-420.[ZHAO Y F,ZHU J,XU Y.Establishment and assessment of the grid precipitation datasets in China for recent 50 years.Journal of the Meteorological Sciences,2014,34(4):414-420.]
[21]MCKEE T B,DOESKEN N J,KLEIST J.The relationship of drought frequency and duration to time scales//Proceedings of the Eighth Conference on Applied Climatology.American Meteorological Society Boston,1993:179-184.
[22]张强,邹旭恺,肖风劲,等.气象干旱等级(GB/T 20481-2006).北京:中国标准出版社,2006:14-15.[ZHANG Q,ZOU X K,XIAO F J,et al.Classification of Meteorological Drought(GB/T 20481-2006).Beijing:Standard Press of China,2006:14-15.]
[23]KEYANTASH J,DRACUP J A.The quantification of drought:An evaluation of drought indices.Bulletin of the American Meteorological Society,2002,83(8):1167-1180.
[24]YEVJEVICH V M.An objective approach to definitions and investigations of continental hydrologic droughts.Hydrology Papers(No.23),Colorado State University,Fort Collins,1967.
[25]陈璐,郭生练,闫宝伟,等.基于Copula函数的干旱特征分析.水资源研究,2012,1(4):186-194.[CHEN L,GUO S L,YAN B W,et al.Drought characteristics analysis using Copulas.Journal of Water Resources Research,2012,1(4):186-194.]
[26]陆桂华,闫桂霞,吴志勇,等.基于Copula函数的区域干旱分析方法.水科学进展,2010,21(2):188-193.[LU G H,YAN G X,WU Z Y,et al.Regional drought analysis approach based on Copula function.Advances in Water Science,2010,21(2):188-193.]
[27]SHIAU J T,SHEN H W.Recurrence analysis of hydrologic droughts of differing severity.Journal of Water Resources Planning and Management,2001,127(1):30-40.
[28]左冬冬,侯威,颜鹏程,等.基于游程理论和两变量联合分布的中国西南地区干旱特征研究.物理学报,2014,63(23):45-56.[ZUO D D,HOU W,YAN P C,et al.Research on drought in Southwest China based on the theory of run and two-dimensional joint distribution theory.Acta Physica Sinica,2014,63(23):45-56.]
[29]肖名忠,张强,陈晓宏.基于多变量概率分析的珠江流域干旱特征研究.地理学报,2012,67(1):83-92.[XIAO M Z,ZHANG Q,CHEN X H.Spatial-temporal patterns of drought risk across the Pearl River Basin.Acta Geographica Sinica,2012,67(1):83-92.]
[30]XU K,YANG D W,XU X Y,et al.Copula based drought frequency analysis considering the spatio-temporal variability in Southwest China.Journal of Hydrology,2015,527:630-640.