Earth Syst. Sci. Data, 13, 2923–2944, 2021 https://doi.org/10.5194/essd-13-2923-2021 © Author(s) 2021. This work is distributed under the Creative Commons Attribution 4.0 License. Glacier changes in the Chhombo Chhu Watershed of the Tista basin between 1975 and 2018, the Sikkim Himalaya, India Arindam Chowdhury1, Milap Chand Sharma2, Sunil Kumar De1, and Manasi Debnath1 1Department of Geography, North-Eastern Hill University, Shillong 793022, Meghalaya, India 2Centre for the Study of Regional Development, Jawaharlal Nehru University, New Delhi 110067, India Correspondence: Sunil Kumar De (
[email protected]) Received: 25 November 2020 – Discussion started: 28 January 2021 Revised: 19 April 2021 – Accepted: 10 May 2021 – Published: 17 June 2021 Abstract. Glaciers of the Tista basin represent an important water source for mountain communities and a large population downstream. The article presents observable changes in the Chhombo Chhu Watershed (CCW) glacier area of the Tista basin, the Sikkim Himalaya. The CCW contains 74 glaciers (> 0.02 km2) with a mean glacier size of 0.61 km2. We determined changes in glaciers from the declassified Hexagon Keyhole-9 (KH- 9) (1975), Landsat 5 Thematic Mapper (TM) (1989), Landsat 7 Enhanced Thematic Mapper Plus (ETMC) (2000), Landsat 5 TM (2010), and Sentinel-2A (2018) images. The total glacier area in 1975 was 62.6 ± 0.7 km2; and by 2018, the area had decreased to 44.8 ± 1.5 km2, an area loss of 17.9 ± 1.7 km2 (0.42 ± 0.04 km2 a−1). Clean glaciers exhibited more area loss of 11.8 ± 1.2 km2 (0.27 ± 0.03 km2 a−1) than partially debris-covered and maximally debris-covered glaciers.