Melt season hydrological characteristics of the Parlung No. 4 Glacier, in Gangrigabu Mountains, south-east Tibetan Plateau

With global warming, hazards relating to glacial melt, such as glacial lake outburst floods, are becoming progressively more serious. However, glacial melt processes and their hydrological consequences are very poorly understood. This study collected glacier discharge data from the terminus of the Parlung No. 4 Glacier throughout the melt season (May-October) during 2008, 2010, 2011 and 2012 to study its specific hydrological characteristics. Time series and multivariate regression analyses were employed to investigate the relationships between discharge and meteorological factors involved, as well as their correlation to discharge estimations. The 0- to 3-day time series analysis showed that discharge rates were highly autocorrelated and that discharge was significantly positively correlated to air temperature, vapour pressure and daily incoming shortwave radiation as well as weakly positively correlated to precipitation. A multiple-regression exponential model using the independent variables of the daily mean temperature and the vapour pressure exclusively was applied to simulate daily discharge in the basin with a high degree of accuracy. On average, July yielded the maximum monthly mean discharge, followed by August. Discharge in July and August accounted for 53% of the total discharge during the main melt season. The daily cycle of discharge changed as the melt season progressed, reflecting hydrological processes and characteristics of snow melt and glacier ice/snow melt, as well as their transitional periods. Subsequently, regular variations in the characteristics of the diurnal cycle of discharge, storage and delay were observed as the melt season progressed. In addition, the reasons behind the inter-annual variation in the characteristics of discharge and glacier discharge from the Tibetan Plateau and its surrounding areas are compared and discussed. Copyright (c) 2015 John Wiley & Sons, Ltd.