Tsutomu Kadota

Predictions of changes of glacier mass balance in the Nepal Himalaya and Tibetan Plateau : a case study of air temperature increase for three glaciers

Annual mass exchange differs between maritime and continental glaciers. A common characteristic of these glaciers in Asian high-mountain areas is that most of the annual accumulation occurs in summer. Since variations in mass balance of a summer-accumulation type of glacier are quite sensitive to variations in summer air temperature, shrinkages of such glaciers due to climate warming are predicted by the use of simplified experimental relations between air temperature and mass balance, disregarding variation of other climatic variables such as cloudiness and precipitation. The results predict that both small and large maritime glaciers are more sensitive to warming than a continental ice cap. A small glacier would disappear in a few decades if the air temperature persisted a few degrees above that of an equilibrium state of mass balance.

Land-surface hydrological processes in the permafrost region of the eastern Tibetan Plateau

In order to examine and record the effects of permafrost on hydrological processes in the cryosphere, the hydrology of the ground surface layer was investigated in the permafrost region of the eastern Tibetan Plateau. Water budget components in the surface layer were calculated on a daily basis. Variability in the water budget components, and its causes, was investigated on both seasonal and daily bases. The results showed that coupling of the thaw– frost cycle to seasonality in precipitation is the principal control of hydrological processes in the upper 2 m of the soil. When the ground surface begins to thaw, from the surface down, the concentration of melt water within a thin surface layer leads to a rapid increase in evaporation, then a slight decrease occurs in the continuous permafrost region as the wet soil zone moves downward. An analysis of seasonal variation in the water budget components demonstrated that the dominant water cycling arises from the processes of precipitation and evaporation that are typical in this region. The freeze – thaw cycle, which affects seasonal soil moisture, water storage, evaporation, and the mobilization of water through the soil and vegetation during the summer monsoon season, is a dominant feature of the land-surface hydrology in the permafrost region of the eastern Tibetan Plateau. q 2003 Elsevier B.V. All rights reserved.

Snow ablation in an open field and larch forest of the southern mountainous region of eastern Siberia

Abstract The southern mountainous taiga region of eastern Siberia is the runoff source area of the basins of the rivers Lena and Amur, where snowmelt discharge is an important hydrological process. To evaluate the effect of the sparse larch forest canopy on snow ablation and energy balance in the snow-pack, meteorological conditions and snow ablation were observed in a larch forest (LF) and an open field (OP). At the beginning of snowmelt, the snow water equivalent was 54.4 and 95.5 mm at OP and LF, respectively. The snow disappeared at LF three days later than at OP. Sublimation accounted for about 8% of snow ablation at both sites from 1 April to 5 May 2002, the snowmelt period. The energy balance of the snowpack at the two sites was dominated by the net all-wave radiation onto the snow surface. The difference in snowmelt between the sites was primarily caused by a difference in the net all-wave radiation. Snow surface albedo correlated with snow surface density for densities from 150 to 350 kg m−3 at both sites.

The Effect of Impurities on the Surface Melt of a Glacier in the Suntar-Khayata Mountain Range, Russian Siberia

We investigated characteristics of impurities and their impact on the ablation of Glacier No.31 in the Suntar-Khayata Mountain Range in Russian Siberia during summer 2014. Positive degree-day factors (PDDFs) obtained from 20 stake measurements distributed across the glacier’s ablation area varied from 3.00 to 8.55 mm w.e. K-1 day-1. The surface reflectivity measured with a spectrometer as a proxy for albedo, ranged from 0.09 to 0.62, and was negatively correlated with the PDDF, suggesting that glacier ablation is controlled by surface albedo on the studied glacier. Mass of total insoluble impurities on the ice surface varied from 0.1 to 45.2 g m-2 and was not correlated with surface reflectivity, suggesting that albedo is not directly conditioned by the mass of the impurities. Microscopy of impurities revealed that they comprised mineral particles, cryoconite granules, and ice algal cells filled with dark-reddish pigments (Ancylonema nordenskioldii). There was a significant negative correlation between surface reflectivity and algal biomass or organic matter, suggesting that the ice algae and their products are the most effective constituents in defining glacier surface albedo. Our results suggest that the melting of ice surface was enhanced by the growth of ice algae, which increased the melting rate 1.6 - 2.6 times greater than that of the impurity free bare-ice.

Surface mass balance on Glacier No. 31 in the Suntar–Khayata Range, eastern Siberia, from 1951 to 2014

This study presents a 64-year (1951–2014) reconstruction of the surface mass balance of Glacier No. 31, located in the Suntar-Khayata Range of the eastern Siberia, where the ablation zone is characterized by the extensive dark ice surface. We use a temperature index-based glacier mass-balance model, which computes all major components of glacier mass budget and is forced by daily air temperature and precipitation from a nearby meteorological station. The glacier shows a mean annual mass balance of–0.35 m w.e.a–1 during the past 64 years, with an acceleration of–0.50 m w.e. a–1 during the recent years. A cumulative mass loss of the glacier is ~22.3 m w.e. over the study period, about 56% of which is observed during 1991–2014. In addition to the contribution of temperature rise and precipitation decrease to recent mass loss of the glacier, an experimental analysis, in which the clean and dark ice surfaces are respectively assumed to cover the entire ablation zone, indicates that dark ice surface, caused by insoluble impurities consisting of mineral dusts, cryoconite granules, and ice algae, plays a crucial role in the changing mass balance through enhancing melt rates in the ablation zone of the glacier.

Correction to “Sublimation from snow surface in southern mountain taiga of eastern Siberia”

[1] In the paper ‘‘Sublimation from snow surface in southern mountain taiga of eastern Siberia’’ by Yiensheng Zhang, Kazuyoshi Suzuki, Tsutomu Kadota, and Tetsuo Ohata (Journal of Geophysical Research, 109, D21103, doi:10.1029/2003JD003779, 2004), the first author’s name was misspelled. The correct spelling appears above. JOURNAL OF GEOPHYSICAL RESEARCH, VOL. 110, D08109, doi:10.1029/2005JD005902, 2005