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中文摘要: (1)分析得到勤试验站13个观测指标中的145个统计项中的前6个主成分最大载荷因子的多年变化特征是:年日照时数70~80年代持续下降;年平均气温60~80年代下降,90年代以后显著增高;10月份平均风速70年代中期至80年代中期下降,之后增大;年大风日数呈波浪式上升;年最大风速有增无减;8月降水量相对稳定。当地的气候环境在80年代中期以前朝良性方向发展,80年代中期以来进一步恶化。(2)年沙尘暴日数的多年变化特征与年日照时数有较大的相似性;年平均最高气温、年平均地温和7月份极端最高气温与年平均气温的多年分
中文关键词: 沙漠,生态气候,变化特征,主成分分析
Abstract:(1)The changing characteristics of maximum loading factors of the first 6 principal components in Principal Component Analysis (PCA) on 145 statistical items of 13 observed indexes were:annual sunshine hours decreased gradually during the 1970s and the 1980s,but it has increased evidently since the begining of the 1990s:and there was a decreasing trend in annual average temperature from the 1960s to the 1980s,but it has rised evidently since the 1990s;average wind velocity in October gradually reduced from the mid 1970 to the mid 1980s,then increased;the days of annual strong wind increased wavily;annual maximum wind velocity constantly lifted the change of rainfall in August.The local climatic conditions had a good developing trend before the middle of 1980s,but since the late 1980s it has been deteriortated.(2)The change of annual sandstorm days was similar to annual sunshine hours;the distributing characters of annual maximum temperature,annual average ground temperature and maximum temperature in July were similar to annual average temperature;the distributing character of annual strong wind days was similar to the average wind velocity in October.(3)The climatic condition had shown some improvements from the mid 1960s to the mid 1980s due to trees planted and shrubs in large scale since the 1960s,and it was deteriorating since the late 1980s concerned with the drop of groud water table and died off of man made sand fix forest.
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引用文本:
常兆丰,2000.民勤西沙窝生态气候变化特征[J].气象,26(5):48-50.
,2000.Analysis on the Characteristics of Climate Change in Xishawo Desert in Minqin[J].Meteor Mon,26(5):48-50.
常兆丰,2000.民勤西沙窝生态气候变化特征[J].气象,26(5):48-50.
,2000.Analysis on the Characteristics of Climate Change in Xishawo Desert in Minqin[J].Meteor Mon,26(5):48-50.