Analysis Of Variation Characteristics Of Cloud And Influence Factors Over The Tibetan Plateau From 2007 To 2014

In this paper, the characteristics of temporal and spatial variations of cloud water path and cloud effective particle radius over the Tibetan Plateau from 2007 to 2014 were analyzed firstly. Then using statistical methods such as the correlation analysis, synthetic analysis to reveal the relationships between temperature, water vapor and cloud water path, and view,further explain the relative contributions of water vapor and temperature to cloud water path which is according to Clausius-Clapeyron equation from the physical point of view. Main conclusions are as follows:(1) Over the Tibetan Plateau from 2007 to 2014, the variation of CWPI and CERI played a great leading role of the variation of CWPC and CERI then the water cloud.(2) Over the Tibetan Plateau from 2007 to 2014, the CWPs exist stable area of high and low value which is that the higher value changed more drastically. The mean value of CERC and CERI performance on the grounds of southeast to northwest reduces, and s the mean value of CERL is more obvious regional differences. The water cloud is mainly in the dramatic changes in the Three-River Source Region, and ice clouds is in the dramatic changes in the southeast side and southwest side of the Tibetan Plateau.(3) Over the Tibetan Plateau from 2007 to 2014, the CWPC and CWPI were significantly reduced in the east of 88°E of the Tibet Plateau, and water clouds in the vast majority of the Tibetan Plateau area were significantly reduced, which the Yarlung Zangbo Valley area are the linear decreasing trend of high value closed center. The CERL and CERI were significantly reduced in the Yarlung Zangbo Valley area, and were significantly reduced in the east of 88°E of the Tibet Plateau in summer that CERI reduced much more than CERL, also, CERL significantly decreased in the Yarlung Zangbo Valley area.(4) The characteristics of vertical distribution indicated that the vertical distribution of liquid cloud water content is more simple than the ice cloud water content that the middle of Himalayas mountain and the southeastern of the Tibetan Plateau were the highest and most vigorous area for vertical development of liquid cloud water content. Under the influence of monsoon in winter, cloud development of high latitude area were weak. Ice cloud formation mechanism is very complex, because of the influence of terrain, the southwestern side of the Tibet Plateau is a major area for ice cloud development. Vertical distribution characteristics of liquid cloud effective particle radius and liquid cloud water content is very similar, however ice cloud particle effective radius and the corresponding cloud water content in the vertical distribution is very different.(5) Correlation analysis showed that, when the correlation between monthly anomaly of air temperature and monthly anomaly of CWP before 2011 is better then after 2011, the correlation between monthly anomaly of column water vapor content and monthly anomaly of CWP after 2011 is better then before 2011.However,no matter before or after 2011, the monthly anomaly of relative humidity which is influenced by water vapor and temperature had a good correlation with CWP.(6) Using the empirical formula to analyze the influence of specific humidity and temperature on the relative humidity, it is found that compared with temperature and specific humidity are all changed in relative humidity, the relative humidity changed only by specific humidity reduced 0.73%, and relative humidity changed only by the temperature reduced 0.15%. Before 2011, the relative contribution of temperature on relative humidity is over the relative contribution of specific humidity on relative humidity, after 2011 is the opposite.(7) Over the Tibetan Plateau from 2007 to 2014, the effect of the distribution of annual and seasonal average linear trend of water vapor and temperature on which of the relative humidity has obvious regional difference. Except autumn, the year and other seasons which in Tarim Basin and its surrounding areas water vapor and temperature has positive effect on the relative humidity produced. In the hinterland of the Qinghai Tibet Plateau where the water vapor is difficult to transport into, the water vapor has a positive effect on the relative humidity, while the temperature has a negative effect on the relative humidity.