Decadal and multi-dacadal variations of the Asian Anticyclone in climate models, impact on lower stratospheric water vapour variability

Long-term variations of the UTLS Asian summer monsoon anticyclone are investigated in reanalyses and in a set of high-top coupled atmosphere-ocean sea-ice models, participating to the CMIP5 excercise. The anticyclone is analysed in terms of geopotential fields anomalies, circulation streamfunction and its temperature structure. We investigate if long-term variability of water vapor distribution (and biases) in the NH lower stratosphere are connected to the representation of variations in summer anticyclones in models.