Long-term trends in maximum, minimum and mean annual air temperatures across the Northwestern Himalaya during the twentieth century

摘要

The study reveals significant rise in air temperature in the northwest Himalayan (NWH) region by about 1.6pC in the last century, with winters warming at a faster rate. The diurnal temperature range (DTR) has also shown a significantly increasing trend. This appears to be due to rise in both the maximum as well as minimum temperatures, with the maximum increasing much more rapidly. The results are in contrast to the findings in the Alps and Rockies where the minimum temperatures have increased at an elevated rate. Conforming to the global trends, the study confirms episodes of strong warming and cooling in the NWH in the last century. Real warming appears to have started from late-1960s and highest rate of increase was experienced in the last two decades. The study also shows teleconnections between temperatures and an epochal behaviour of the precipitation till late-1960s. These teleconnections seem to have weakened gradually since then and rapidly in the post-1991 period, indicating the waning effect of the natural forcings in this period.