Atmospheric moisture transport and dynamic precipitation controls on the Tibetan Plateau ; Atmosphärischer Wassertransport und dynamische Kontrollfaktoren des Niederschlags auf dem Tibetischen Plateau

The Tibetan Plateau (TP) is the origin of many large Asian rivers, which provide water resources for large regions in south and east Asia. Therefore, the water cycle on the TP and adjacent high mountain ranges, in particular the precipitation distribution and variability play an important role for the water availability for billions of people in the downstream regions of the TP. The respective influence of the Indian and East Asian summer monsoon on TP precipitation and regional water resources, together with the detection of moisture transport pathways and source regions are the subject of recent research. The aim of this thesis is to gain a better understanding of the spatial and temporal precipitation variability on the TP. In order to do so we examine the moisture transport to and on the TP, analyse the underlying processes leading to enhancement or suppression of precipitation, and examine how those processes are affected by the mid-latitude westerlies and the monsoon system. A newly developed high-resolution dataset, the High Asia Refined analysis (HAR), is used to examine atmospheric water transport (AWT) and dynamical factors that influence precipitation variability in the TP region. The HAR is the result of dynamically downscaling an operational analysis. Due to the higher spatial and temporal resolution of the HAR, it better represents the complex topography of the TP and surrounding high mountain ranges than coarse-resolution data sets like reanalyses, thereby reducing precipitation biases. Analysing the AWT, we focus on spatiotemporal patterns, vertical distribution and transport through the TP boundaries. The results show that the mid-latitude westerlies have a higher share in summertime AWT over the TP than assumed so far. High mountain valleys in the Himalayas facilitate AWT from the south, whereas the high mountain regions inhibit AWT to a large extent and limit the influence of the Indian summer monsoon. Our results show that 36.86.3% of the atmospheric moisture needed for precipitation comes ...