High resolution modeling of the winter-to-early spring precipitation response over the western Himalayas to climate change
Abstract
Non-monsoonal precipitation over the western Himalayas (WH) during winter-to-early spring months primarily comes from eastward propagating synoptic-scale weather systems known as western disturbances (WDs). Observed climate datasets indicate an increasing trend of synoptic-scale WD activity in the past few decades and has contributed to enhanced propensity of daily precipitation extremes over the WH. It is not yet clear as to whether these regional changes are manifestations of climate change. We conducted a suite of long-term climate experiments using a global variable-grid climate model with high-resolution telescopic zooming over the South Asian region to examine this scientific problem. The present findings show that human-induced climate change has implications on the rising trend of synoptic-scale WD activity and precipitation extremes over the WH during the recent few decades, and these changes cannot be explained by natural forcing alone. A stronger surface warming, in response to climate change, is noted over the vast expanse of the high-elevated eastern Tibetan Plateau relative to the western side. The model simulations show that strengthening of positive east-west temperature gradient across the Tibetan Plateau tends to alter the background mean circulation in a manner as to favor amplitude enhancements of the synoptic-scale WDs and orographic precipitation over the WH. With continuation of global warming in future and enhancement in the east-west temperature gradient across the Tibetan highlands, the trend of precipitation extremes over the WH and synoptic-scale WD activity are projected to rise into the 21st century.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.C43D1522R
- Keywords:
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- 0720 Glaciers;
- CRYOSPHERE;
- 0726 Ice sheets;
- CRYOSPHERE;
- 0732 Icebergs;
- CRYOSPHERE;
- 0750 Sea ice;
- CRYOSPHERE