甘肃河东地区地表湿润特征及其气候影响因子  

Surface humidity index and the impacting climatic factors in Hedong region of Gansu province

作　　者：赵一飞[1] 张勃[1] 张多勇[1,2] 张建香[1] 何旭强[1] 孙力炜[1] 

机构地区：[1]西北师范大学地理与环境科学学院,兰州730070 [2]陇东学院,庆阳745600

出　　处：《地理科学进展》2013年第1期95-104,共10页Progress in Geography

基　　金：国家自然科学基金项目(40961038);生态经济学省级重点学科项目(5002-021);西北师范大学知识与科技创新工程项目(NWNU-KJCXGC-03-66)

摘　　要：利用甘肃河东地区13个气象站1960-2010年的逐日气象资料,选取FAO Penman-Monteith法计算了各站的潜在蒸散量,由此得出各站点的湿润指数;然后采用线性趋势法、Morlet小波、自然正交分解(EOF)和反距离加权插值等方法,对河东地区湿润指数的时空变化特征进行分析,进而探讨对影响其变化的气象要素。结果表明:①1992年之前,甘肃河东地区地表相对湿润,1992年之后变得干旱,年地表湿润指数的年际变化率为-0.02/10a,相关系数为0.2946(P<0.05),季节上除冬季呈轻微增加外,其他各季都呈减少趋势,空间分布上表现出明显的南北差异,从南到北呈减少趋势;②年湿润指数空间异常分布主要表现为"全区一致性"和"南北反向变化"两种模态,同时也存在着19 a、5 a和11 a左右的变化周期,并于1994年发生了由湿向干的转变;③湿润指数与降水量、相对湿度呈显著正相关,与日照时数、潜在蒸散、风速和最高气温呈显著负相关。Based on the climatic factors,such as daily maximum temperature,minimum temperature,precipitation,relative humidity,wind speed and sunshine duration,measured daily at 13 stations from 1960-2010 in Hedong region of Gansu province,potential evaporation is calculated for the region using the UN Food and Agriculture Organization（FAO） Penman-Monteith model,which allows the calculation of the surface humidity index for the location of each station.The characteristics of spatial-temporal variations of the humidity index are then analyzed by using the linear regression,Morlet wavelet,Empirical Orthogonal Function（EOF） and Inverse Distance Weighted（IDW） methods,and the climatic factors impacting the surface humidity index are investigated.The results indicate that the study region was wetter before 1992,and the humidity index has been in a downward trend since 1960s,with an interannual decreasing rate of 0.02/10a in the last 51 years and a correlation coefficient of 0.2946（P0.05）.With the exception of slight increase in winter season,the humidity index decreased in other three seasons.The spatial pattern of the change of humidity index of the study region showed clear difference between the south and the north,with the humidity index decreasing from south to north.The abnormal spatial pattern resides in two aspects： the uniformity of the whole area,and the opposite changes in the south and the north.In the meantime,the periods of 19a,5a and 11a also existed for interannual changes of the humidity index,with the turning point from wet to dry in the year of 1994.Furthermore,in the past 51 years,the climatic factors showed different impacts on the humidity index change in different seasons;the humidity index had positive correlations with precipitation and relative humidity,but negative correlations with sunshine duration,potential evaporation,wind speed and maximum temperature.

关 键 词：Penman-Monteith法 潜在蒸散量 湿润指数 影响因素 河东地区 甘肃省 

分 类 号：P461[天文地球—大气科学及气象学]