Temporal Variations of Air Temperature, Precipitation and River flow in the Karakoram Mountains and Surrounding Areas

Abstract:

Climatic conditions in the Karakoram mountains are often considered to differ from those elsewhere in the Himalayan region as glaciers appear to have shown limited decline, if not some growth, during the late twentieth century. The so-termed Karakoram Anomaly suggests that either precipitation as snow increased or, in contrast to conditions in other mountain areas, summer temperatures either declined or at least failed to increase at rates similar to those observed elsewhere. Meteorological records from stations albeit at relatively low elevations in valleys within the Karakoram in the period 1900-2013 have been examined together with those from surrounding mountain areas with a view to determining temporal patterns of climatic variation and the extent to which such variations in the Karakoram have differed from those observed in the western Himalaya, on the western part of the Xizang plateau, and in the southern Pamirs. In areas surrounding the Karakoram, air temperatures increased from the 1960s to 1970s and then decreased to the late 1980s/early 1990s before rising to maxima in the 2000s. At Karakoram valley stations, temperatures declined from the 1960s/1970s to the 1990s. Air temperature hardly recovered into the 2000s. Precipitation in the both Karakoram and surrounding areas varied considerably from year-to-year. At Karakoram stations, winter precipitation increased slightly from the 1990s to 2000s whilst summer precipitation increased steadily from the 1960s. Summer precipitation both increased and decreased in surrounding areas. Valley bottoms in the Karakoram are arid, but snowfall at higher elevations on glaciers reduces flow whilst there is little seasonal snow off-glacier to melt and moderate year-to-year variations in runoff.