In this study, a coupled and improved snow-glacier runoff modeling framework has been presented, which aims to separate the snowmelt runoff from glaciated and non-glaciated areas. To fulfil the above objective, the two hydrological models such as the conceptual Glacier-hydrological Model (GSM-SOCONT) and Soil & Water Assessment Tool (SWAT) have been used over the Teesta river Himalayan catchments. The temperature index model (TIM) based degree-day approach (DDA) in GSM-SOCONT model has been modified and radiation components were added. The R² values computed between observed and modeled discharge (1991–2005) was improved from 0.55 to 0.63 after adding the radiation components. Initially, SWAT model has been used for the simulation, calibration, and optimization of the various snowmelt hydrology parameters. Then, SWAT model based optimized parameters and outcomes were used as inputs to set up the GSM-SOCONT model. After simulating/separating snow melts from glaciated and non-glaciated areas, the optimized snow-glacier parameters from the improved GSM-SOCONT (1991–2005) were re-input to the SWAT for the projection of snowmelt scenarios (2008–2100) utilizing the downscaled Coupled Model Intercomparison Project Phase 5 (CMIP5) Global Circulation Models (GCMs) datasets. The snow water equivalent (SWE) reconstructed for the year 2005 from the MODIS satellite snow covers (i.e. ranges from 80 to 138 mm) found comparable to the SWAT generated SWE (i.e. ranges from 86 to 115 mm). Based on the future projections of snowmelt, the earlier snow-melting or shifts have been observed in extreme high and low elevation areas of the Sikkim Himalaya.

在这项研究中，提出了一个耦合和改进的雪冰川径流建模框架，该框架旨在将融雪径流与冰川和非冰川地区分开。为了实现上述目标，已在Teesta河喜马拉雅流域使用了两个水文模型，例如概念性冰川水文模型（GSM-SOCONT）和土壤与水评估工具（SWAT）。修改了GSM-SOCONT模型中基于温度指数模型（TIM）的度日法（DDA），并添加了辐射分量。R ²加上辐射分量后，观测到的放电和模拟放电（1991-2005年）之间的计算值从0.55提高到0.63。最初，SWAT模型已用于各种融雪水文参数的模拟，校准和优化。然后，使用基于SWAT模型的优化参数和结果作为输入来建立GSM-SOCONT模型。在模拟/分离了冰川和非冰川地区的融雪后，将改进的GSM-SOCONT（1991–2005）中优化的冰川参数重新输入到SWAT中，以利用以下方法预测融雪情况（2008–2100）：缩小规模的耦合模型比较项目第5阶段（CMIP5）全球流通模型（GCM）数据集。2005年根据MODIS卫星雪盖重建的雪当量（SWE）范围从80到138毫米）与特警生成的SWE（即86到115毫米）相当。根据对融雪的未来预测，在锡金喜马拉雅山的高海拔和低海拔地区都观察到了较早的融雪或移动。