Met clues to Uttarakhand's extreme weather events
doi:10.1038/nindia.2016.147 Published online 10 November 2016
Analysing 100 years of meteorological data, researchers have uncovered some clear trends in the regional climate of Uttarakhand, the north Indian state which saw large scale loss of life and property following a catastrophic cloudburst in 2013. The analysis also shows subtle interconnections between the regional climate events and the global climate variability indices.
The study, conducted by a team of researchers from various Indian institutes, focussed on Uttarakhand, the picturesque state nestled in the Indo-Himalayan mountain range that has been at the receiving end of the extreme rainfall events. The 2013 cloudburst has called for greater scrutiny of the regional climate.
Air temperature and rainfall data showed a steep increase in air temperature in pre-monsoon months, and a spike in the amount of rainfall received in June and July since 1997. Also, the total monsoon precipitation (cumulative rainfall received between June and September) is linked to the Eurasian Snow Cover (ESC) extent — positive ESC values witnessing above normal rainfall, and negative ones witnessing the opposite. Curiously, the negative phases of the Arctic oscillations seem to encourage extreme rainfall events in the state. In a warming world, a negative index of the Arctic oscillation appears to further increase extreme rainfall events over northwest Himalayas.
The Himalayan mountains are known to be extremely vulnerable to climate change due to their tropical vicinity. The authors believe that there is a need to set up a dense array of ground-based climate monitoring stations which can help ground-teething of satellite-derived meteorological parameters — important to anticipate the rapidly changing climate of the region.
1. Agnihotri, R. et al. Assessing operative natural and anthropogenic forcing factors from long-term climate time series of Uttarakhand (India) in the backdrop of recurring extreme rainfall events over northwest Himalaya. Geomorph. (2016) doi: 10.1016/j.geomorph.2016.10.024