Abstract:
In this study, past (1970-2005) as well as future long term (2011-2099) trends in
various extreme events of temperature and precipitation have been investigated over selected
hydro-meteorological stations in the Sutlej river basin. The ensembles of two Coupled Model
Intercomparison Project (CMIP3) models: third generation Canadian Coupled Global Climate Model
and Hadley Centre Coupled Model have been used for simulation of future daily time series of
temperature (maximum and minimum) and precipitation under A2 emission scenario. Large scale
atmospheric variables of both models and National Centre for Environmental Prediction/National
Centre for Atmospheric Research reanalysis data sets have been downscaled using statistical
downscaling technique at individual stations. A total number of 25 extreme indices of temperature (14)
and precipitation (11) as specified by the Expert Team of the World Meteorological Organization and
Climate Variability and Predictability are derived for the past and future periods. Trends in extreme
indices are detected over time using the modified Mann-Kendall test method. The stations which
have shown either decrease or no change in hot extreme events (i.e., maximum TMax, warm days,
warm nights, maximum TMin, tropical nights, summer days and warm spell duration indicators)
for 1970–2005 and increase in cold extreme events (cool days, cool nights, frost days and cold spell
duration indicators) are predicted to increase and decrease respectively in the future. In addition,
an increase in frequency and intensity of extreme precipitation events is also predicted.
