Cloud distribution characteristics over the Tibetan plateau

Abstract

We use GMS5 satellite data and ISCCP cloud detection algorithm to study the characteristics of monthly mean cloud distribution and diurnal variation over the Tibetan Plateau. We simply classify total cloud into low, middle and high categories according to the height of cloud top. For the spatial distribution, during winter season both total and high cloud amounts of the north part of the Tibetan Plateau are larger than that of the south part of the Tibetan Plateau, but during summer season the distribution patterns are the reverse, that is, the cloud amounts of the south part of the Tibetan Plateau are larger than that of the north part of the Tibetan Plateau. For the diurnal variation, the total cloud amount begins to increase after sunrise and reaches maximum at 09GMT and 06GMT for midsummer season and other months respectively. After that total cloud amount decreases slowly. But the diurnal variation of high cloud amount is different from that of total cloud amount, high cloud amount begins to increase at noon time and reaches maximum at 09GMT and 12GMT for winter and summer seasons respectively. The diurnal variation of both total and high cloud amounts of the Tibetan Plateau is larger than that of the north part of the Indian Island.