The retreat of the glaciers on Mount Kenya is quantitatively well documented for the intervals 1899–1963 and 1963–1987. The ice recession between 1899 and 1963 was strongly dependent on solar radiation geometry. By contrast, the ice thinning between 1963 and 1987 amounted to about 15 m for all glaciers regardless of topographic location. This suggests that climatic forcings other than solar radiation have become more prominent.

Sensitivity analyses indicate that the energy supply of about 5 W m−2, required to produce the observed ice thinning through melting, can be accounted for by a combination of climatic forcings. The direct effect of changing atmospheric composition (“greenhouse effect”) on the net longwave radiation could have contributed less than 1 W m−2. A warming of 0.0 to 0.2°C would translate into an additional downward-directed sensible heat transfer of 0.0 to 1.4 W m−2. A 0.1 to 0.2 g kg−1 increase in specific humidity would, through savings in the latent heat transfer, contribute 2 to 4 W m−2.

Long-term station records show little warming trend for East Africa itself. However, mid-tropospheric specific humidity trends of about 0.6 g kg−1 over the past two decades in the equatorial belt have been reported in the literature, and considered to be consequences of “global warming” and the “greenhouse effect”.

Viewed in perspective, the ice wastage on Mount Kenya between 1963 and 1987 appears to have been driven primarily by three climatic forcings, conceivably all steered by the “greenhouse effect”: a direct forcing through the net longwave radiation; an indirect forcing through warming and therefore enhanced sensible heat transfer; and another indirect forcing through warming (not necessarily in the region itself), leading to increased (advected) atmospheric moisture, and hence to reduced latent heat transfer, this last line of control being the most important.

The jökulhlaups in the Yarkant (Yarkand) River are usually caused by the sudden drainage of glacier-dammed lakes through rapidly expanding subglacial channels. The lakes are dammed by Keyajir (Kyagar) Glacier and Telamukanli (Singye) Glacier which are situated in the upper reaches of the Keleqin (Shaksgam) River. In recent years the glaciers have become thinner, and the glacier-dammed lakes and their outbursts have become smaller.

Glacier meltwaters are an important component of surface water resources in western China. Based on glacier inventories, the total glacier area in China is 5.87 x 104km2, the second largest for an Asian country. The total storage of water in glaciers is about 5132 x 103 km3, and the mean annual amount of glacier melt runoff is about 5.64 x 1010m3, o r 2% of the total surface water resources of China. From the late 1950s to the present, measurements have been undertaken of about twenty mountain glaciers, and data on hydrology and meteorology obtained. The relationship between heat balance and glacier ablation has been investigated but for glacierized areas where there are no data, ice-melt runoff can be estimated from climatic data. Runoff of glacier meltwater decreases with increasing aridity of the climate. The impact of glacier meltwater on the regimes of mountain streams in different environments are described in this paper.

Avalanches are a widespread hazard that cause serious damage in the southeastern Tibetan Plateau. Abundant solid precipitation and high relief are favourable for avalanche occurrence. The monsoon climate brings a lot of precipitation which, however, is not well distributed. Avalanches are most common around the margins of the plateau. Wet snow avalanches occur most frequently. Based on data on precipitation and topographical relief, a map is drawn showing the areal distribution of avalanche hazards.

Hubbard Glacier advanced across the entrance of Russell Fiord in May 1986, transforming the fiord into a lake, which began filling with fresh water. The dam failed in October 1986. The calving terminus of Hubbard Glacier has been mapped with increasing frequency for nearly a century. A mapping interval of a few years establishes that the terminus has made a slow, but accelerating, advance. Recently the terminus has been mapped several times per month using vertical photography, ground surveys, and time-lapse cameras. At this frequency of observation, the terminus position is found to fluctuate seasonally. These seasonal fluctuations are compared with those of Columbia Glacier, where a longer detailed record is available. Although Columbia Glacier is now undergoing a drastic retreat, it continues to have seasonal length changes similar to those it experienced before the retreat began. The lengths of both Columbia and Hubbard Glaciers are extended in the spring, and retracted in the fall. The relatively long period of record for Columbia Glacier shows consistent seasonal variation in length and, when compared with the short period of record for Hubbard Glacier, suggests that there are consistent seasonal differences in length at Hubbard also. The lower Hubbard Glacier diverges, feeding ice into Disenchantment Bay and Russell Fiord, and advances and retreats synchronously over most of its width. The tidal current, which passes through the 250–500 m wide entrance to Russell Fiord, does not affect the seasonal advance and retreat in that area significantly.

Austdalsvatn in western Norway was regulated in 1988 as a reservoir for a hydropower development. From a pre-1988 water level of 1157 m a.s.l. the new water level will vary more or less annually from 1170 to 1200 m a.s.l. The outlet glacier Austdalsbreen calves into this reservoir. About 1600 m up-valley from its terminus the glacier flows over a bedrock riegel that is, at its lowest point, ∼ 15 m above the projected maximum lake level of 1200 m. As a result of the increase in water level, the surface velocity near the front has increased from about 0.07 to 0.13 m d−1.

Calculations suggest that the glacier terminus will retreat about 750 m in 50 years. The measured response of the glacier terminus for the first three years is in good agreement with the simulations.

From field observations and historical information, it is found that there are generally three end moraines in front of glaciers in the Gongga mountains. These moraines were formed during the Little Ice Age and represent three glacier advances. During the last 100 years, the glaciers have been in continuous retreat except for two periods of stability or even slight advance, one in the beginning of the 20th century, up to the 1920s, and the other from the middle 1960s to the early 1980s. The amplitudes of glacier fluctuations were greater on the east slope than on the west.

Investigations of Zelunglung and Midui Glaciers in southeast Tibet, China, indicate that they have some characteristics of surge-type glaciers. There have been two extraordinary movements of Zelunglung Glacier, one in 1950 and one in 1968. A collapse of the terminus area took place in 1984. Midui Glacier experienced extraordinary movements about 55 years ago and also in 1988. During these events, the glacier termini reached moraines formed during neoglaciation and the Little Ice Age. The advances of the two glaciers are not related to climate variation. The glaciers caused serious disasters with loss of life and property, and disruption of transportation corridors.

The total area of glacierization of the Tien Shan in the boundary area of the USSR is about 8000 km2. The computation of mass balance was determined for this area in 12 river basins.

In computation procedure, the vertical profile of snow accumulation in these regions and exponential dependence of variation of ablation with altitude are used. Thus the mass balance in each basin, bn, was calculated on the basis of these curves and represented in its relation with the equilibrium line altitude (ELA). It is shown that the relation ELA = f(bn) is linear when the range of bn values is close to zero, and in all altitude intervals this relation can be described by hypsographic curves, in all basins bn positive up to an ELA elevation of 3450 to 3500 m a.s.l. For average annual altitude of ELA, bn is negative for all regions. So the glaciers of these mountains add about 4 km3 of water to the total annual runoff.

Floods caused by outbursts from lakes dammed either by end moraines or by glaciers are the most important disasters related to glaciers in China. The former occur mainly in Tibet, and the latter in Xinjiang Province. Exceptionally large outbursts from lakes dammed by end moraines have been reported 19 times since 1935 amd 30 outbursts from glacier-dammed lakes have been recorded since 1956. Outbursts from lakes dammed by end moraines are closely associated with ice avalanches, and 79% of all dam failures occur during July to August when ice avalanches are frequent. Outbursts from glacier-dammed lakes often occur in years of very high air temperature, and 63.3% of all failures are between August and September when the storage capacities of glacier lakes reach their limit. Whether or not the end moraine-dammed lakes are of potential danger depends on the flow of the glacier that feeds the lake and the vertical distance between the terminus of the glacier and the level of the lake. The frequency of periods of outbursts from glacier-dammed lakes corresponds to the periods of glacier advance. During the last 160 years, three periods of frequent outbursts from glacier-dammed lakes have occurred. Their duration has been 20 to 30 years and the interval between them about 40 years. The frequency of glacier lake outbursts could increase early in the next century if glaciers advance and dam up new marginal lakes in response to a cold period since 1940.

A mathematical model is proposed to simulate the spatial and temporal variations in snow temperature. The model is based on the non-steady, one-dimensional, heat-conduction equation with internal heat source. It gives the change in time of the internal temperature field of the snow as it responds to varying surface temperature and periodic solar radiation. Verification of the model is accomplished by comparing the calculated results with observed data. The model may serve as a basis for quantitative investigations of snow temperature and temperature gradient, and relevent problems such as energy-mass transfer processes. Moreover, it allows better understanding of the relationship between external atmospheric conditions and the internal thermal regime of dry snow covers in the western Tien Shan mountains.

According to the analysis of grey scale range on MSS-4, -5, -6 and -7 channel image films for five snow-ice categories on glacier surface, the grey scale among snow, bare ice, ice pinnacle, moraine-covered ice surface and gully bed has been spread nonlinearly by using duplicative processing on high-contrast film. As a result of the rescaling of grey levels, the colour differences of morphological features of Rongbu Glacier in the Qpmolangma region have been increased on false colour composite photography. It is also shown that using MSS-6 to composite false colour images compared to MSS-5 will supply more information for the interpretation of the glacier area.

Spatial-temporal variations in the extent of the seasonal snow cover of the upper reaches of the Yellow River were studied sytematically, using NOAA, Landsat, MSS and TM images, supported by ground-truth data. Effects of changing areal extent of snow cover on river flow were also examined. Spring-runoff forecasting models were developed, based on ridge regression methods and Grey theory, employing satellite snow-cover and actual hydrometeorological data to forecast inflow to the Longyang Gorge reservoir for ten-day periods between April and early June. Forecast precision is within ±15% of the actual observation. Separating snow-cover data by elevation zone improves the accuracy of forecast over lumping snow cover over the entire basin.

In May of 1990, three research groups from China, the Soviet Union and the United States visited Glacier No. 1 in the Ürümqi river basin, Xinjiang Uygur Autonomous Region, northwestern China, in a cooperative effort to examine differences in mass-balance calculations resulting from sampling and estimation procedures. Three different snow-depth data sets were collected consisting of: (1) high-resolution depth transects covering the glacier, (2) depths taken from the permanent stake network, and (3) an intermediate data set constructed using the stake network and supplementary depth data from locations not covered by the stake network. The glacier was divided into ten elevation zones and the data were registered to a digital elevation model for analysis. Results show that the permanent stake network provides an accurate estimate of total mass balance if certain techniques are used for extrapolation to higher elevations, although estimates of mass balance for particular regions of the glacier are not accurate. Some regions were overestimated while others were underestimated, leading to a good overall estimate. The intermediate-resolution data set provided better within-zone estimates of mass balance, but was less accurate than the stake network for total mass balance.

In the past decade the interest of many scientists worldwide has been attracted to the central Asian area of China. A number of gaps in scientific knowledge have been closed, and many significant discoveries have been made.

The most important achievement is the ice-core research by the Sino-American Joint Expedition to the Dunde Ice Cap, Qilian mountains, that established a record of ten thousand years of climatic and environmental change. In addition, in cooperation with scientists from Japan, Switzerland and the Soviet Union, studies have been carried out focusing on glacier mass balance, heat balance, the mechanism and formation of glacial runoff, and high mountain climates. This work has been done in the Tien Shan, west Kunlun, Tanggula, Nyaingentanglha and Gongga mountains.

In addition, through joint efforts of scientists from China, Nepal and Canada, important advances have also been made in studies of glacier lake outburst floods and debris flows in the Karakoram and the Himalayas, and in mountainous areas in southeastern Tibet.

The glaciers in central Asia will continue to be an important research area for glaciologists from all over the world in the coming decade.

Industrial activity in the Noril’sk mountains since the 1930s has changed the landscape and formed artificial banks, ridges and terraces. New water courses have been formed and snow has been removed to places where it has accumulated year by year. The ground temperature has increased by 0.3 to 0.5°C down to a depth of 30 to 50 m, melting has increased in the permafrost layer and artificial ground has become more unstable, leading to landslides and mudflows. Material in dumping sites has frozen and turned into rock glaciers, chemical pollutants have accumulated in snow and extremely high concentrations are observed in meltwater during spring. The gravitational instability of mountain and piedmont landscapes increases with human activities and the landscapes thus changed cause greater danger from slumps, mud flows and avalanches.

In this study a new microwave snow retrieval algorithm was developed to account for the effects of atmospheric emission on microwave radiation over high-elevation land areas. This resulted in improved estimates of snow-covered area in western China when compared with the meteorological station data and with snow maps derived from visible imagery from the Defense Meteorological Satellite Program satellite. Some improvement in snow-depth estimation was also achieved, but a useful level of accuracy will require additional modifications tested against more extensive ground data.

Methods of quantitative evaluation of the influence of local factors such as slope exposure (aspect and gradient) and types of vegetation on the distribution of snow cover found in the northern Tien Shan are described. This investigation is based on regular measurements of snow depth and density at different altitudes and exposures, and with different vegetation types. A strong statistical relationship was obtained between snow cover on the one hand and slope exposure and vegetation types on the other. Local factors have a stronger influence on the distribution of snow cover than elevation. These methods were used for the estimation of the distribution of snow cover in a typical river basin. The results obtained differ significantly from the results of evaluations made by traditional methods.