近50年云南省极端气候事件时空变化特征

Spatial and Temporal Change Characteristics of Extreme Climate Events in Yunnan Province in Recent 50 Years

为研究云南省极端气候事件的时空变化特征,利用云南省28个气象站点1965-2014年逐日气象数据,首先分析了年均气温和年均降水量的时空变化特征,然后通过计算22个极端气候指数,对近50年来的12个极端气温指数和10个极端降水指数进行了时空变化特征分析。结果表明:(1)云南省1965-2014年年均气温总体上呈波动上升趋势,年际气温距平升温率为0.3℃/10 a,年均降水总体上则呈波动下降趋势,年际降水距平递减率为18.3 mm/10 a,年均气温和降水的空间分布大致都呈现从南向北递减的趋势;(2) 12个极端气温指数中,冷夜日数TN10p、冷昼日数TX10p、霜冻日数FD0、冰冻日数ID0和冷持续指数CSDI的线性倾向率都呈下降趋势,暖夜日数TN90p、暖昼日数TX90p、最高气温极大值TXx、最高气温极小值TXn、最低气温极大值TNx、最低气温极小值TNn和热持续指数WSDI的线性倾向率都呈上升趋势,表明冷指数变暖或减少,暖指数变暖或增加;(3) 10个极端降水指数中,湿日降水量PRCPTOT、强降水量R95p、极强降水量R99p、低强度降水日数R10mm、中等强度降水日数R20mm、最大5日降水量RX5day和连续湿润日数CWD整体都呈下降趋势,降水强度SDII、最大1日降水量RX1day和连续干旱日数CDD整体都呈上升趋势,表明云南省整体年均降水量和降水次数在减少,但极端降水事件和降水强度反而在增加,干旱化趋势明显。

In order to study the spatio-temporal change characteristics of extreme climate events in Yunnan Province,the daily meteorological data of 28 meteorological stations from 1965 to 2014 were used to analyze the temporal and spatial variation characteristics of annual average temperature and annual average precipitation in Yunnan Province.Then,by calculating 22 extreme climate indices,the temporal and spatial change characteristics of 12 extreme temperature indices and 10 extreme precipitation indices in recent 50 years were analyzed.The results show that:(1) The annual average temperature in Yunnan Province from 1965 to 2014 showed an overall upward trend,and the interannual temperature anomaly warming rate was 0.3 ℃/10 a,while the annual average precipitation showed a fluctuating downward trend,and the interannual precipitation anomaly decline rate was 18.3 mm/10 a.The spatial distribution of annual average temperature and precipitation was decreasing from south to north.(2) Among the 12 extreme temperature indices,the linear tendency rates of TN10 p,TX10 p,FD0,IDO and CSDI showed a downward trend,while those of TN90 p,TX90 p,TXx,TXn,TNx,TNn and WSDI showed an upward trend.These indicated that the cold index was warming or decreasing,and the warm index was warming or increasing;(3) Among the 10 extreme precipitation indices,PRCPTOT,R95 p,R99 p,R10 mm,R20 mm,RX5 day and CWD all showed a downward trend,while SDII,RX1 day and CDD showed an overall upward trend.These indicated that the overall annual average precipitation and precipitation frequency were decreasing,but the numbers of the extreme precipitation events and precipitation intensity were increasing,and the drought trend was obvious in Yunnan Province.