Abstract:
We introduce a Rainfall, Snow and Glacier melt (RSG) standardized anomaly (SA) index to reflect water
availability in cold river basins by taking into account snow and glacier melt that influence seasonal
water availability. The study takes advantage of a high-resolution Water and Energy Budget-Based
Hydrological Distributed Model with improved snow physics (WEB-DHM-S) at a grid size of 5 km to
quantify hydrological regimes in a typical cold river basin in the Tibetan Plateau (Lhasa River basin as
a demonstration site) from 1983 to 2012. Standardized anomaly index was utilized as drought
Indicator whereby each meteo-hydrological parameter involved in drought quantification was fitted to
a distribution pattern on a monthly basis. Akaike Information Criterion and Bayesian Information
Criterion were used as selection criteria. Drought indices were computed from the model inputs and outputs,
which included RSG for meteorological drought, soil moisture (surface and root-zone) for agricultural
drought and discharge and groundwater level for hydrological drought. From spatial and
temporal analyses, drought occurred in 1984, 1988, 1995, 1997, 2009 and 2010, with the highest severity
in August, September, July, August, June and June, respectively. This study addresses the glacierized cold
river basin’s dryness by considering the contribution of snow and glacier in drought quantification, an
integration of meteorological, agricultural and hydrological was performed to highlight drought hotspots
in the Lhasa River Basin. To the best of our knowledge, this is the first drought study in Lhasa River Basin.
