Intraseasonal variability of the Indian Monsoon

• Main Author: Sconcia, Brett
• Published: University of Reading 2000
• Subjects: 551.51
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.646013

The Indian Monsoon is an extremely important and large-scale meteorological phenomenon that occurs with monotonous regularity every year in the northern hemisphere summer. India and the surrounding regions depend on the monsoon's rains which, although averaged over a season are relatively constant, can vary on timescales of days to weeks with devastating economic and social impact. This study was performed in an effort to gain a little more insight in to the intraseasonal variability of the Indian Monsoon. This was done with the help of an extensive observational study using ECMWF reanalysis data and also some modelling with a simple atmospheric model. In order to interpret results, degrees of simplification will be introduced by compositing and averaging processes that betray the complexities of the monsoon system. However, it will be shown that this allows well-defined atmospheric structures to be obtained for what are known as active and break states of the monsoon. Some observational aspects of the active and break monsoon states will be shown, highlighting the major differences between the two states. This will be followed by a series of modelling experiments with increasing sophistication, although remaining very simple. The results of these will show enough consistency with observations to allow an investigation in to the effects of ENSO on the intraseasonal variability of the Indian monsoon.