Energy- and mass-balance comparison between Zhadang and Parlung No. 4 glaciers on the Tibetan Plateau

Tibetan glaciers experience spatially heterogeneous changes, which call for further investigation of the mechanisms responsible from an energy and mass perspective. In this study, 2 year parallel observations (August 2010 July 2012) at 5665 m a.s.l. on Zhadang glacier (a subcontinental glacier) and 5202 m a.s.l. on Parlung No. 4 glacier (a maritime glacier) were used to reveal the drivers of surface energy and mass balance at these sites. Glacio-meteorological data show that air temperature and specific humidity were 1.7 degrees C and 0.5 g kg(-1) lower on Zhadang glacier than on Parlung No. 4 glacier. The mass accumulation occurred primarily before the Indian summer monsoon onset on Parlung No. 4 glacier and after its onset on Zhadang glacier. Point net mass loss was 2.5 times larger on Parlung No. 4 glacier than on Zhadang glacier, mainly due to the difference in melt energy. Overall, the physical mechanisms controlling the mass and energy difference can be attributed to both the feedback role of surface albedo through different snow accumulation characteristics and longwave radiation emission of the atmosphere due to different meteorological backgrounds. Finally, a review of the few studies dealing with energy balance on the Tibetan glaciers describes the possible spatial characteristics requiring further investigation in the future on larger spatial and temporal scales.