2001-2011年青藏高原东北边坡地带云水资源分析

利用青藏高原东北边坡地带(32°～37° N，99°～104° E)22个地面气象站2001年6月至2011年5月每日8次地面观测资料，以及2001-2011年NCAR/NCEP月平均再分析资料，通过统计分析和NOAA HYSPLIT_4（混合单粒子拉格朗日积分）水汽轨迹模型，主要分析了青藏高原东北部边坡地带近10 a云量、云状的发展特征及其与水汽的关系。结果表明：① 近10 a，高原东北边坡地带多年平均总云量与低云量的变化具有较好的一致性；全年云量春夏季增加尤为明显。② 全年发生雨雪天气时，卷云出现概率最高，其次为高层云，积云最低；高原东北边坡地带对流云出现概率明显比非对流云出现的概率高。③ 水汽是决定高原降水分布和对流云变化的主要依据之一，水汽主要来源于700 hPa，且水汽通量可以较好地反映低云量的多寡。 

Analysis on Cloud and Vapor Flux in the Northeast of the Qinghai-Tibet Plateau during the Period from 2001 to 2011

The northeast of the Qinghai-Tibet Plateau is the intersection transitional zone of the Qinghai-Tibet Plateau and the Loess Plateau,also the transitional zone of agriculture and animal husbandry,the terrain is complex,and it is often affected by various weather systems,so the response of climate change is very sensitive.It is characterized by the fragile ecological environment,soil erosion and water loss,pasture degeneration,land desertification and various environmental problems.Therefore,it is very meaningful for further understanding the climatic characteristics and climate change in the Qinghai-Tibet Plateau by analyzing the climate change and its trends in the northeast of the plateau.However,the recent discussion about cloud cover and its related factors in the northwest or in the whole plateau was insufficient.So it is necessary to study the temporal change of cloud cover and more detailed weather characteristics related to cloud cover over the northeast of the Qinghai-Tibet Plateau.It is of great significance for implementing artificial precipitation and developing air resources. Based on the daily cloud cover data observed by 22 meteorological stations and the NCAR/NCEP reanalysis data in the northeast of the Qinghai-Tibet Plateau（32°-37° N,99°-104° E） during the period from 2001 to 2011,the development characteristics of cloud cover and the relationship between cloud cover and vapor flux in the northeast of the Qinghai-Tibet Plateau in recent 10 years were studied in terms of the statistical analysis and the HYSPLIT₄ Model.The results showed that the total cloud cover and the low cloud cover over the study area was decreased from the south to the north.There was an increase trend of total cloud cover and low cloud cover over the study area during the period from 2001 to 2011,especially in spring and summer.When rain or snow occurred,appear probability of cirrus was the highest,then that of altostratus,and that of cumulus was the lowest.Appear probability of convective cloud was higher than that of non-convective cloud over the northeast of the Qinghai-Tibet Plateau.Water vapor is one of the main factors affecting the distribution of precipitation and the change of convective cloud.Water vapor flux came mainly from 700 hPa layer,and water vapor flux could reflect the low cloud cover well.