Indian Forum for Water Adroit

If Rain Falls in India and No One Reports It, Are Historical Trends in Monsoon Extremes Biased?

Pankaj Dey

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  • Institute : Indian Institute of Science
  • Programming language : MATLAB, R
Previously reported trends in daily monsoon rainfall since 1950 have been estimated using interpolated weather station observations released by the India Meteorological Department. The number of reporting weather stations changes over time, and poor coverage by weather stations can overlook extreme rainfall events. By applying the interpolation of this changing network to satelliteā€based rainfall data, we show that the changing coverage of weather stations in the Indian rainfall data leads to spurious increases in extreme rainfall. This suggests that previously reported trends of extreme rainfall are biased positive. Access to the raw weather station data would improve our ability to track changes in the Indian monsoon and assess modeled predictions given climate change.