Armstrong's research interests include: remote sensing of snow, ice, and frozen ground, snow cover and glacier mass extent as indicators of climate change, properties of avalanche snow, and data set and cryospheric product development.
Current Research: The Glaciers of the Himalaya-Karakoram-Hindu Kush Region
Snow and ice constitute a significant component of the hydrologic regime of the high alpine catchments of the world such as the Himalaya-Karakoram-Hindu Kush (HKH) region. The timing and spatial patterns of snow-and ice-melt play key roles in providing water sources for irrigation, hydropower generation and general consumption. Hydrologic processes in the high-altitude regions of the world are particularly sensitive to climate change because of the predominant role of snow and glaciers.
The overall objective of this study is to develop an accurate, comprehensive assessment of the snow and glacier contribution to the water resources originating across the greater HKH region. Approximately one third of the world’s human population depends to some degree on fresh water availability within the HKH hydrologic system and planning for future changes is a high priority. However, realistic, accurate and comprehensive assessments of the current and future availability and vulnerability of the water resources in these regions are not possible until the existing hydrologic regime of these mountains is better defined, the relationship between snow, glaciers and streamflow is evaluated in quantitative terms, and the contribution from other sources of streamflow is examined. To date, this comprehensive goal has not been not been addressed in a coordinated and systematic manner and conclusions reached by other investigations have often been based on anecdotal evidence that is typically not spatially representative. Specifically, our project objectives are being accomplished through the application of a comprehensive suite of satellite remote sensing and ground based data as input to appropriate snow and ice melt models. A series of distributed process models, in conjunction with area-altitude relationships for snow, ice, and temperature data, are being used to assess the general hydrometeorological environment of these mountain catchment basins
Although often considered as a single region, the HKH represents a wide range of climate conditions where precipitation and basin runoff decrease considerably from the east to west as a direct result of the weakening influence of the summer monsoon. The glacier accumulation and ablation patterns are distinctly different, seasonally and spatially, across the region. In the east, the summer season combines both accumulation at the highest elevations with melt below, while in the west there is a clear pattern of summer melt and winter accumulation, similar to North America and Europe. Earlier results have indicated that only about 5% or less of the river flow in the eastern Himalaya is the result of glacier melt (Alford et al. 2010). Outside the monsoon-dominated eastern Himalaya, the contribution from melting glacier ice has been estimated to be as much as 30 percent or more, but no accurate quantitative assessments have been undertaken. Therefore, the current phase of our project focuses on quantifying the contribution of melting glacier ice, melting seasonal snow, rainfall, and groundwater to total streamflow in the western Himalaya, and extending into the Pamir mountain range of Central Asia, based on melt models and stream geochemistry.
Alford, D., Armstrong, R. and Racoviteanu, A. 2010. Glacier retreat in the Nepal Himalaya: An assessment of the role of glaciers in the hydrologic regime of the Nepal Himalaya. Report to South Asia Sustainable Development (SASDN) Office, Environment and Water Resources Unit, The World Bank, Washington, DC.