Analyses of Observed and Anticipated Changes in Extreme Climate Events in the Northwest Himalaya

Dharmaveer Singh,Shive Rai,Rajan Gupta,Neha Jain,Sudhir Kumar,Sanjay Jain

doi:10.3390/cli4010009

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.

Highlights

An extreme weather or climate event is an event that is rare at a particular place and time of year [1]
According to Easterling et al.[2], extreme events can be grouped into two broad categories: (1) yearly extreme events or weather events based on simple statistics such as very low or very high daily temperature and heavy daily rainfall, and (2) more complex event-driven extremes, e.g., droughts, floods, heat waves and hurricanes which do not necessarily occur every year at a given location
No particular trends could be perceived in number of summer days (SU25), cool nights (TN10p), warm days (Tx90p) and warm spell duration indicators (WSDI) and in magnitude of maximum TMax

Summary

Introduction

An extreme weather or climate event is an event that is rare at a particular place and time of year [1]. (1) yearly extreme events or weather events based on simple statistics such as very low or very high daily temperature and heavy daily rainfall, and (2) more complex event-driven extremes, e.g., droughts, floods, heat waves and hurricanes which do not necessarily occur every year at a given location. These extreme events are of great concern because slight changes in frequency or intensity of extreme events can have important effects on society and natural ecosystems. Similar kinds of studies were undertaken by many authorsin

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Conclusion