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<p>The Indus Forum – a research programme being explored by ICIMOD, the International Water Management Institute, and the South Asia Water Initiative – had its first working group meeting in November 2019. The aim was to deliberate on the research areas and funding opportunities that can best support the forum. Participants agreed on the operational mechanism of the joint programme and explored ways to ensure its sustainability. Additionally, the forum’s working groups endorsed its operational manual and identified ICIMOD as forum secretariat. </p>
Historical records of the fluctuations of glaciers in the Himalayas and Trans-Himalayas date back to the early 19th century. Local and regional syntheses of 112 of these fluctuation records are presented in this study. The local syntheses deal with fluctuations of glaciers in Kanchenjunga-Everest, Garwhal, Lahaul-Spiti, Kolahoi, Nanga Parbat, Karakoram (north and south sides), Rakaposhi-Haramosh, Batura Mustagh, and Khunjerab-Ghujerab. Regional syntheses deal with the composite record and the differentiation of records by glacier type (longitudinal versus transverse) and regional setting (Himalayan versus Trans-Himalayan). In a gross regional sense Himalayan and Trans-Himalayan glaciers have been in a general state of retreat since AD 1850. Filtering of the fluctuation records with respect to glacier type and regional setting reveals that the period AD 1870 to 1940 was characterized by alternations in the dominancy of retreat, advance, and standstill regimes.
The results presented in this study indicate the possibility of seasonal runoff prediction when satellite-derived basin snow-cover data are related to point source river discharge data for a number of years. NOAA-VHRR satellite images have been used to delineate the areal extent of snow cover for early April over the Indus and Kabul River basins in Pakistan. Simple photo-interpretation techniques, using a zoom transfer scope, were employed in transferring satellite snow-cover boundaries onto base map overlays. A linear regression model with April 1 through July 31 seasonal runoff (1974-1979) as a function of early April snow cover explains 73% and 82% of the variance, respectively, of the measured flow in the Indus and Kabul Rivers. The correlation between seasonal runoff and snow cover is significant at the 97% level for the Indus River and at the 99% level for the Kabul River. Combining Rango et al.'s (1977) data for 1969-73 with the above period, the April snow cover explains 60% and 90% of the variance, respectively, of the measured flow in the Indus and Kabul Rivers. In an attempt to improve the Indus relationship, a multiple regression model, with April 1 through July 31, 1969-79, seasonal runoff in the Indus River as a function of early April snow-covered area of the basin and concurrent runoff in the adjoining Kabul River, explains 79% of the variability in flow. Moreover, a significant reduction (27%) in the standard error of estimate results from using the multi-variate model. For each year of the study period, 1969-79, a separate multiple regression equation is developed dropping the data for the year in question from the data-base and using those for the rest of the years. The snow cover area and concurrent runoff data are then used to estimate the snowmelt runoff for that particular year.The difference between the estimated and observed dircharge values averaged over the 11 year study period is 10%. Satellite derived snow-covered area is the best available input for snowmelt-runoff estimation in remote, data sparse basins like the Indus and Kabul Rivers. The study has operational relevance to water resource planning and management in the Himalayan region.
This study evaluates the estimates of seasonal snowmelt runoff in the Sutlej, Indus, Kabul and Chenab rivers derived from the model of snow cover area vs. runoff against those obtained from cross correlation of concurrent flows in the rivers. The concurrent flow correlation model explains more than 90 per- cent of the variabililty in flow of these rivers. Compared to this model, the model of snow-cover area vs. runoff explains less of the variability in flow. However, unlike the snow-cover model, the concurrent flow correlation model cannot be used for operational forecasting procedures. Where the strength of correlation is high, the concurrent flow correlation model has potential for use in retrospective analysis of flow for estimating missing data, extending time series and for evaluating estimates derived from other models. In the Himalayan basins under study and at least for the period under observa- tion, the concurrent flow correlation model provides a set of results with which to compare the estimates from the snow cover model.
Patterns of annual variation of air temperature in the world provide two types of the patterns of ablation rate of the glacier, namely the "summer-maximum" and the "non-maximum" through a year, while those of precipitation and air temperature provide three types of accumulation rate, namely, the above two and the "winter-maximum". In six combinations of these types, annual variation of balance rate can be classified into the types of the winter-maximum, the non-maximum and the summer-maximum. The "summer-accumulation type glaciers" in the Nepal Himalaya, which have more accumulation in summer than winter in the whole area of a glacier, belong to the non-maximum type of balance rate. In the case of this type glacier, direct observations of accumulation and ablation are quite difficult, since accumulation and ablation mainly occur simultaneously in summer. Therefore, the methods of estimation of accumulation and ablation are discussed. Accumulation can be estimated on the basis of the linear relation between surface air temperature and the probability of occurrence of solid precipitation in all cases of precipitation. Local characteristics of melting process of precipitation elements which control such relation are described. For the estimation of ablation, the effect of high albedo of new snow is important for the summer-accumulation type. The variation of mass balance through the balance year in the case of the summer-accumulation type is compared with that of the winter-accumulation type.
Log-linear, exponential and fractional relations for estimating seasonal\nsnowmelt from early-spring snow accumulation in the Indus and Kabul\nriver basins in the western Himalayas are developed with a view to\nimprove the prediction given by bivariate linear regression models\nearlier developed by the senior author in collaboration with others.\nThis study shows that although the transformed data may improve the\nabove prediction, they fail to satisfy the condition of nonlinearity; a\nproperty that must be borne in mind before recommending any nonlinear\nregression model. Any further improvement in the prediction of seasonal\nflow volume from basin snow cover area, therefore, has to come from\nwithin the domain of linear regression models only or from improvements\nin the original input data.
The relative importance of data on winter snow accumulation and summer (monsoon) rainfall for estimating annual runoff in the Jhelum River basin, Punjab Himalaya, Pakistan, has been investigated. Strong correlations were found between point measurements of the annual maximum of snowpack water equivalent and of total winter precipitation in the Kunhar sub-basin, and total annual discharge. In addition, total winter snowfall showed a generally significant correlation with annual discharge. Elevation did not appear to play a strong role in determining the usefulness of these measurements, whereas location within the basin relative to large scale precipitation patterns did, in some cases. Monsoon rainfall appeared to be a very poor indicator of annual discharge. The results also suggest that the operation of a continental scale negative feedback mechanism between Eurasian snow cover and the Indian monsoon might be felt in this region of the Himalaya.
Seasonal and annual distribution of rainfall and snowfall with elevation has been studied for outer, middle and greater Himalayan ranges of Chenab basin in the western Himalayas. Rainfall and snowfall exhibited different trends with eleva-tion on the windward and leeward slopes of the three ranges of Himalayas. Sea-sonal characteristics of rainfall have shown a spill over effect on leeward side during winter, pre-monsoon, and post-monsoon seasons in the outer Himalayas. The role of orography in the middle Himalayas was found to be more pro-nounced for both rainfall and snowfall in comparison to other ranges of Hima-layas. Variation of snowfall with elevation was more prominent in comparison to variation of rainfall. In the greater Himalayan range it is found that rainfall descreases exponentially with elevation and snowfall increases linearly. Rainfall becomes negligible at elevations beyond 4,000 m on the windward side of the greater Himalayan range. Efforts have also been made to explain whether varia-tion in precipitation is due to changes in precipitation intensity or number of pre-cipitation days or a combination of both.