Popis: |
Hindu Kush-Karakoram-Himalaya (HKKH) region represents one of the major non-polar cryosphere domains on the Earth. This region feeds three major rivers namely: the Indus, the Ganga and the Brahmaputra and supports a huge population of more than 1 billion people. There is wide variability and uncertainty in data on most aspects of this cryospheric domain. The behaviour of glacial melting in HKH region is highly heterogeneous with the highest negative mass balance in the eastern Himalaya, relatively less negative mass balance in the western Himalaya with positive mass balance in the Karakoram. The hydrological budget of the higher Himalayan rivers depends on the precipitation (snowfall and rainfall) but the available estimates on snow cover and rainfall are highly variable and in few cases appear to be unacceptable. Reported precipitation variability for the Indus basin is more than 250%, for the Ganga basin it is 100% and for the Brahmaputra basin the variability is more than 240%. The estimate on glacial cover and its volume in the Himalayan-Karakoram regions shows variability of more than 130 and 250% respectively. The available estimates on the glacial melt fraction also show high variability, for example for the Indus basin the variability is ~170%, for the Ganga basin it is ~300% and for the Brahmaputra basin the variability is more than 100%. The number of glaciers in the Himalaya and the adjacent mountains differ in the different glacier inventories. Similarly, published data on basin wise glaciated area varies from 300% for Indus basin, 200% for the Ganga basin and it is more than 450% for the Brahmaputra basin. The present work reviews current status of the Himalayan cryosphere. |