【作者】 陈丽娟；

【导师】 陈友飞；

【作者基本信息】 福建师范大学 ， 地图学与地理信息系统， 2017， 硕士

【摘要】 全球变暖使区域水文气象要素发生变化,造成更频繁的极端天气气候事件,对社会经济、自然生态系统和人类生命影响巨大,同时引起植被生长环境的变化。因而,极端气候要素的时空变化特征及植被状态的响应关系成为当前研究的热点。为进一步揭示区域极端气候要素的时空变化及植被状态的响应特征,本文主要开展以下3方面研究:1)基于23个气象站点1960-2014年逐日降水、最高和最低气温及日平均气温资料,选取6个极端气温指数和6个极端降水指数,运用线性趋势估计法、最小二乘法和Mann-Kendall(MK)趋势检验等方法,分析福建省极端气候事件的时空变化特征。极端气温指数包括冷昼天数(TX1Op)、冷夜天数(TN1Op)、冷持续指数(CSDI)、暖夜天数(TN90p)、作物生长期(GSL)和暖昼天数(TX90p),极端降水指数为总降水量(PRCPTOT)、最大1日降水量(RXlday)、持续降水日数(CWD)、最大5日降水量(RX5day)和持续干旱日数(CDD)。2)基于2000-2014年MOD13A3数据,以GIS、RS等遥感平台做为处理手段,分别从年际变化、季节变化和月变化三个时间尺度,分析福建省植被ND VI变化特征。3)结合区域内NDVI以及极端气温、极端降水指数时空变化的差异特征,研究2000-2014年植被NDVI对极端气候要素的多尺度相关性特征。结果表明:1)区域尺度下,冷指数呈现降低趋势,暖气温指数呈现出增加趋势,这与全球变暖趋势相一致。表征极端低温事件的指数,即冷持续指数、冷昼天数和冷夜天数,下降站点数占全部站点数的83%、87%和96%,其中冷持续指数(P<0.012)和冷夜天数(P<0.0001)下降趋势显著。而表征高温事件的作物生长期、暖昼天数和暖夜天数均呈增加趋势,且暖夜天数和冷夜天数大于暖昼温度和冷昼天数的上升幅度。2)在过去55a期间,区域平均总降水量、强降水日数、持续干旱日数、1日最大降水量和5日最大降水量等极端降水指标均呈增加趋势,而持续降水日数呈减少趋势,因此极端强降水事件在时间上更为集中,福建省洪涝风险上升。3)年植被NDVI整体呈现增加趋势,其受气温的影响较为显著,且在2014年达到最高值,气温在年际变化上呈不显著下降趋势。冬季和春季,植被生长呈增加趋势,且冬季增加幅度最为明显,夏季和秋季则呈现减少趋势;夏季和秋季植被生长与气温相关关系最显著,春季则主要受降水变化影响,但相关性不显著。(4)极端气候指数与NDVI相关分析表明,植被NDVI均值与极端气温类指数相关性较高。其中,植被NDVI与冷夜天数相关性在0.05水平上显著,与冷昼天数相关性在0.01水平上显著性,而植被NDVI与极端降水指数相关性不大,说明该区植被生长的主要影响因子是气温,降水为次要因子。更多还原

【Abstract】 Global warming has changed regional hydrometeorology and has influenced the condition of vegetation,with more frequent extreme weather/climate events.The extreme weather/climate event has significant impacts on economy,natural ecological system,and human life.Therefore,it is of great significance to understand the spatiotemporal characteristics of climatic extremes and their relations with the conditions of vegetation.To further reveal the spatiotemporal characteristics of climatic extremes and their relationship with the condition of vegetation,this study mainly conducted following three researches.The first research is to analyze the spatiotemporal characteristics of extreme weather/climate events over Fujian Province during 1960-2014,based on daily maximum temperature,daily minimum temperature and daily mean temperature records at 23 meteorological stations,using six extreme temperature indices,six extreme precipitation indices,linear trend estimation method,least square method and Mann-Kendall(MK)trend test method.The extreme temperature indices are cold days and cold nights(TX10p),(TN10p),cold duration index(CSDI),warm nights(TN90p),crop growth period(GSL)and day days(TX90p).The extreme precipitation indices are total precipitation(PRCPTOT),the maximum 1 day rainfall(RX1day)Last,the number of precipitation days(CWD),the maximum 5 day rainfall(RX5day)and continuous drought days(CDD).The second content is to analyze the variation of NDVI based on different scales,i.e.,the annual,seasonal and monthly changes of vegetation,by using MOD 13A3 data during the period of 2000-2014 data.The last research content is to connect the variation of NDVI and climatic factors and to analyze the correlations of climate extremes and NDVI during 2000-2014.The results show that:(1)At the regional scale,the cold index decreased,the heating temperature index showed an increasing trend,which is consistent with the trend of global warming.The extreme low temperature event characterization index,cold index continued,cold day days and cold nights,the number of stations decreased the number of stations accounted for 83%.87%and 96%,including cold duration index(P<0.012)and cold nights(P<0.0001)decreased significantly.Characterization of high temperature events during crop growth period,warm days and warm nights days increased,warm days and cold days and day temperature characterization of nighttime temperature variations of warm night days and cold nights is greater than the change the temperature change in the past.The regional average total precipitation,precipitation days,continuous drought days,extreme precipitation index 1 day maximum precipitation and 5 day maximum precipitation show increasing trends,while consecutive wet days shows decrease trend.It suggest that the risk of flooding has increased in this region.(2)The vegetation NDVI showed an overall increase over Fujian Province,which was affected by air temperature is obvious,and reached the highest value in 2014.Meanwhile,the temperature showed an insignificant decrease in interannual variability,while the precipitation increased significantly.In winter and spring,vegetation growth showed an increasing trend,and the increasing trend in winter is significant.It showed an decreasing trend in summer and autumn,and showed the most significant correlation between vegetation growth and temperature.The vegetation in spring is mainly affected by precipitation,but the correlation is not obvious.(3)The correlation analysis of extreme climate index and NDVI show that average vegetation NDVI and extreme temperature index correlation is higher.Among them,the correlation of vegetation NDVI and cold nights is significant at 0.05 level,and the correlation of vegetation NDVI and cold days is significant at 0.01 level.But there is no correlation between vegetation NDVI and extreme precipitation,indicating that the main influence factor of vegetation is temperature and precipitation is the secondary influence factor over Fujian Province.更多还原