The study presents long-term altitudinal changes and variability (spatial and temporal; during 2000–2017) in the coverage of snow and glaciers in one of the world’s largest mountainous regions, i.e., the Hindu Kush Himalayan (HKH) region. The western zone and high-altitude regions (above 6000 m) show no significant decline in snow cover, whereas the lower-altitude regions (< 6000 m) show a variable but statistically significant decline in snow cover in the central and eastern zones (5 %–15 %).

Data from two instruments (MODIS and MISR) on board the Terra satellite were compared with seven AERONET ground-based stations located in the Middle East and North Africa. The goal was to test which space-borne instrument can better represent ground data over different geographic locations. Comparing satellites’ retrievals with corresponding AERONET measurements shows that space-borne data retrieval accuracy can be affected by landscape and topology.