A discrete view of the Indian monsoon to identify spatial patterns of rainfall

Research output: Contribution to journalArticle

Abstract

We propose a representation of the Indian summer monsoon rainfall in terms of a probabilistic model based on a Markov random field consisting of discrete state variables representing low and high rainfall at grid-scale and daily rainfall patterns across space and in time. These discrete states are conditioned on observed daily gridded rainfall data from the period 2000 to 2007. The model gives us a set of 10 spatial patterns of daily monsoon rainfall over India, which are robust over a range of user-chosen parameters and coherent in space and time. Each day in the monsoon season is assigned precisely one of the spatial patterns, that approximates the spatial distribution of rainfall on that day. Such approximations are quite accurate for nearly 95% of the days. Remarkably, these patterns are representative (with similar accuracy) of the monsoon seasons from 1901 to 2000 as well. Finally, we compare the proposed model with alternative approaches to extract spatial patterns of rainfall, using empirical orthogonal functions and clustering algorithms such as K-means and spectral clustering.

Details

Authors
  • Adway Mitra
  • Amit Apte
  • Rama Govindarajan
  • Vishal Vasan
  • Sreekar Vadlamani
Organisations
External organisations
  • Indian Institute of Technology, Bhubaneswar
  • TIFR Center for Applicable Mathematics
  • International Centre for Theoretical Science, India
Research areas and keywords

Subject classification (UKÄ) – MANDATORY

  • Probability Theory and Statistics
Original languageEnglish
JournalDynamics and Statistics of the Climate System
Volume3
Issue number1
Publication statusPublished - 2018
Publication categoryResearch
Peer-reviewedYes