Pradeep Kumar Mool is a specialist in remote sensing at the International Centre for Integrated Mountain Development (ICIMOD) in Kathmandu. In his current capacity, he studies snow and glacial monitoring, glacial lakes and the risk of Glacial Lake Outburst Floods (GLOFs). Mool spoke to Himal Southasian on the status of ice and water in the region and the Centre's new research conclusions.
What specific observations of precipitation patterns in the region have been made – how much falls in the form of snow, how much in the form of rain?
Very little data on precipitation patterns is available for the region. Few instrumental meteorological observation stations or automatic weather stations exist in high-altitude areas, especially those that include rain and snow gauging. The World Meteorological Organisation, the global agency of the United Nations, specialises in data collection of meteorological, hydrological and other geo-physical observations. It shares meteorological and related data collected by stations worldwide in near real time, through a Global Telecommunication System (GTS). Unfortunately, there are no GTS gauging stations above the snowline for the Himalayan region.
While older data may exist, it is often not available due to national-security concerns. Collection of shareable snow-gauging information along the southern slopes of the Himalaya began only in the last 10 to 15 years. Along the northern slopes, snow gauging started one to two decades back in various glaciated basins in Tibet, including at the Rongbuk Base Camp. The Chinese have recently installed automatic weather stations in the high mountain areas at elevation intervals of 100 metres, from the toe to the tip of the mountain. These stations gather data at every altitudinal zone recording precipitation changes, temperature changes and snowmelt rate. Despite scattered data-gathering, the results generated from these minimal initiatives are not sufficient to make definite conclusions on precipitation in the Himalaya. Snow gauging would be particularly important for the western Hindukush-Himalaya, where the predominant winter monsoon falls in the form of snow. Most of the input to the Indus River basin therefore comes from snowmelt, which includes glacial melt, compared to the primarily rain-fed rivers originating in the Eastern Himalaya such as the Ganga, Brahmaputra and the Meghna. If we look at the Indus basin, input of glacier melt is up to 50 percent; but when we look at the Ganga, reports vary from two to nine percent. If snowmelt would also be accounted for, the contribution to the Indus river basin could go up to 70 or 80 percent in the dry season.
While hard science may be lacking, lay observations can also give us a sense of the changing precipitation trends. Two years back, heavy winter monsoons in Afghanistan and Pakistan were followed by snow avalanches and intense flooding. This is a dramatic shift from reports of drought in the late 1990s – to the extent that, as rumours have it, authorities and scientists recommended spreading charcoal on glaciers to accelerate glacial melt, thereby reducing water-shortage tensions along the Indus basin.