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Glaciers generally accumulate more snow in accumulated zone in rainy season and flow slowly down to terminus. Then, glaciers melt in ablation zone and supply their melting water to downstream. Hence, glacier is an important water resource for ecosystem of downstream region. However, glaciers are shrinking in almost every major glaciated region.

The ongoing volume loss of glaciers has many impacts on our society. Melting water from glaciers is a major contributor of sea level rise, is an important regulator of regional water resources, and often leads to natural hazards like landslides or glacial lake outburst flood. Hence, there is increasing need to estimate the mass loss rate of individual glaciers worldwide by using a global glacier model.

Debris on glaciers affects glacier melting rate and resulting runoff. Because debris accelerates (if debris is thin) or suppresses (if debris is thick) melting rate of glacier, the effect of debris should be taken into account in global glacier models. However, there is no globally completed dataset of debris information.

In this study, we developed a global distribution map of thermal resistance of debris on glaciers at 90-m resolution by using multi-temporal satellite data (ASTER, CERES) and reanalysis meteorological data. Here, "thermal resistance" is a parameter which defined as debris thickness divided by thermal conductivity of debris layer.

We believe that our result provides a solid basis for evaluating debris effects in global glacier models, which could refine future predictions of glacier meltwater and its contribution to regional water availability and global sea level rise.