Spatio-temporal Variation Characteristics And Driving Factors Of Meteorological Drought In Anhui Province

Drought is the most common major meteorological disaster in Anhui Province,which has a serious impact on the economic development.This paper based on the daily precipitation and temperature data of 22 meteorological stations in Anhui Province in recent56 years,analyzed the temporal and spatial variation characteristics of meteorological elements and meteorological drought,reveals the law and characteristics of climate change in Anhui Province,and deeply understands the law of meteorological drought and its relationship with climate change,so as to provide a scientific reference for the regulation of water resources in Anhui Province and provide a reference for drought control Prevention and control is of great significance.The main conclusions of this paper are as follows:(1)According to the standardized precipitation evapotranspiration index(SPEI),the drought in each year is consistent with the actual data,and the analysis of drought in typical drought years is basically consistent with the actual situation,which has good applicability in the analysis of meteorological drought variation characteristics in Anhui Province.(2)The annual scale SPEI decreased at the rate of 0.06/10 a,and changed abruptly in1967.From the perspective of spatial characteristics,the annual scale SPEI changes in most areas of Anhui Province showed an upward trend,with obvious spatial differentiation in each area.The drought situation in the North increased,while that in the South decreased.The seasonal scale SPEI showed a decline in spring and autumn,and an increase in summer and winter,indicating that spring and autumn showed a trend of aridity,while summer and winter showed a trend of wetness;from the perspective of spatial characteristics,the trend of aridity was almost universal in spring and autumn,while the trend of aridity in summer and winter mainly existed in Northern Anhui.(3)In terms of the frequency of annual scale drought,the frequency of drought in Anhui Province is generally high.Among all levels of drought,the frequency of light drought is the highest,and that of special drought is the lowest;From the perspective of the frequency of seasonal scale drought,the drought in spring and autumn is the most serious in Anhui Province.The frequency of drought is not only high,but also the distribution range of severe drought stations is wide,while the drought in summer and winter is relatively light.The annual scale drought station to station ratio decreases at the rate of 0.46/10 a,indicating that the influence scope of drought is gradually becoming smaller;The results show that the influence range of drought in spring and autumn has an increasing trend,while the influence range of drought in summer and winter has a decreasing trend.The annual scale drought intensity has a weak increasing trend;In the seasonal scale,the drought intensity in spring and autumn increased,while that in summer and winter decreased,and there were different degrees of drought in four seasons.(4)In the past 56 years,the average annual precipitation of Anhui province increased at the rate of 27 mm / 10 a,and abrupt changed in 1979;The spatial distribution difference of precipitation is obvious,and gradually decreases from south to north;The precipitation of some stations in northern part of the province has a decreasing trend,and the precipitation of Southern stations is increasing,among which,the precipitation of Chaohu station,Ma'anshan station and Tunxi station is increasing significantly;In the four seasons,the precipitation in summer is the highest,and the precipitation in winter is the lowest,and the precipitation in summer and winter shows an obvious upward trend,while the precipitation in spring and autumn shows a downward trend;From the perspective of spatial characteristics,the spatial distribution of precipitation in four seasons is roughly the same as that of annual precipitation,and gradually decreases from south to north;Most of the precipitation in summer and winter showed an increasing trend,and the increasing trend of precipitation in most stations in the South was greater than that in the north.The precipitation in most stations in spring and autumn showed a downward trend,and the precipitation trend was not significant.(5)The annual average temperature of Anhui Province has increased at 0.2 ? /10 a in the past 56 years,and it has a mutation in 1993;in space,the lowest temperature appears in Dangshan area,the highest value appears in Huangshan area,and the temperature is decreased from southeast to northwest with the increase of latitude;the annual temperature of all stations in Anhui Province has an upward trend,and the temperature changes of all stations except Tongcheng station are all in common The significance test has been passed.The results show that the temperature in four seasons shows an upward trend;except that there is no abrupt change in summer,the abrupt change time of spring temperature is 1996,autumn is 1993,and winter is 1985;from the perspective of spatial characteristics,the average temperature in four seasons generally shows a decreasing trend from south to North,and the coastal area of the Yangtze River Basin is the high value area of temperature,and the distribution of temperature is closely related to the terrain;Except for some stations in summer and autumn,the temperature of all stations in the four seasons showed an upward trend.(6)The changes of precipitation and temperature have an impact on the occurrence and development of drought,but the correlation between precipitation and drought is higher.The correlation between annual scale precipitation and SPI is 0.743,and the correlation between seasonal precipitation and SPI is more than 0.96,and the correlation is tested by significance.