Climatology and trend of cold waves over India during 1971-2010

Abstract

Using Cold Wave (CW) information of 86 stations from Indian main land during the cold weather season (November to March) for the last 40 years (1971-2010), various statistical aspects of cold waves (CWs) and severe cold waves (SCWs) such as climatology and trend were examined. The link of CWs/SCWs with ENSO phases (La Nina & El Nino) was also examined. It was observed that many stations from north, northwest, east and central India together named as core CW zone (CCZ) experienced highest number of CW/SCW waves with relatively higher frequency during January.  Noticeable decrease (increase) in the frequency and spatial coverage of CW/SCW days compared to their climatological values were observed during the El Nino (La Nina) years. There were significant decreasing trends in the CW/SCW days over most of the stations from CCZ. The total number of CW/SCW days/per decade over CCZ showed noticeable decrease during the recent decades 1991-2000 and 2001-2010, which coincided with the warmest decades for the country as well as for the globe. Associated with intense and persistent CW/SCW events, large human mortality were reported during some years of the study period.