Constructing dataset of classified drainage areas based on surface water-supply patterns in High Mountain Asia

Abstract

The High Mountain Asia (HMA) region, ranging from the Hindu Kush and Tien Shan in the west to the Himalaya in the south with an altitude between 2000 and 8844 m, holds the largest reservoir of glaciers and snow outside Earth Polar Regions. In the last decades, numerous glaciers and lake areas there have undergone tremendous changes with water redistribution. In order to increase understanding of the pattern of distribution of water resources, and their dynamic changes at the basin scale, a watershed classification based on the water replenishment patterns dataset was constructed. The input dataset are from the Randolph Glacier Inventory V.6.0 and the vector data of rivers and streams. Four datasets were thus obtained: Glacier-fed and Runoff-fed Drainage Area (GRDA), Glacier-fed and Runoff-free Drainage Area (GDA), Glacier-free and Runoff-fed Drainage Area (RDA), and the Glacier-free and Runoff-free Drainage Area (NGRDA), and the numbers of these four types of basins are 87, 107, 32, and 448 separately. The statistical results show GRDA has the largest surface area, accounting for 82.2% of the total basin area in HMA, mainly in the region of the basin with outflow rivers or streams. Dominated by small basins, the GDA area accounts for the smallest area, only 3.86% and the RDA accounts for 5.62%. For NGRDA, most are with small areas, accounting for 8.32%, and mainly distributes in the closed basin of the Qiangtang Plateau. This dataset provides a fundamental classified data source for research on water resources, climate, ecology, and environment in HMA. The published data are available at https:// data.4tu.nl/download/uuid:d07d748f-d10b-4308-9626-199ef05cc9af/ and http://www.dx.doi.org/10.11922/sciencedb.923.

Remote Sensing and Modeling of the Cryosphere in High Mountain Asia: A Multidisciplinary Review

“…The commonly used multi-spectral classification methods include traditional manual digitization [20,[24][25][26] and semi-automatic and automatic algorithms for glacier mapping with satellite data. The band algebraic operation, namely, multi-spectral classification by threshold segmentation, is the core technique for the semi-automatic and automatic algorithms, including the spectral-band ratio [27][28][29][30][31][32], Normalized Difference Snow Index (NDSI) [33], and unsupervised or supervised classification techniques [20]. Compared with band-based segmentation by image pixels noted above, object-oriented methods accommodating adjacent pixels may limit the salt-and-pepper noise in higherresolution images, connecting homogenous regions and improving accuracy and efficiency.…”

“…Researchers could couple a series of algorithms designed for microwave radiometers (i.e., dual index, decision tree, freezing and thawing discriminant, seasonal threshold, and L-band relative freezing factor threshold) to achieve the surface freeze- [126,127]. (The boundary of HMA is composed of the results by Zhang [128], Lu [29], and Shean [59]).…”

“…The mean annual ground temperature (MAGT)[126,127]. (The boundary of HMA is composed of the results by Zhang[128], Lu[29], and Shean[59]).…”