Changes in seasonal snow cover in Hindu Kush-Himalayan region

Abstract. The changes in seasonal snow covered area in the Hindu Kush-Himalayan (HKH) region have been examined using Moderate – resolution Imaging Spectroradiometer (MODIS) 8-day standard snow products. The average snow covered area of the HKH region based on satellite data from 2000 to 2010 is 0.76 million km2 which is 18.23% of the total geographical area of the region. The linear trend in annual snow cover from 2000 to 2010 is −1.25±1.13%. This is in consistent with earlier reported decline of the decade from 1990 to 2001. A similar trend for western, central and eastern HKH region is 8.55±1.70%, +1.66% ± 2.26% and 0.82±2.50%, respectively. The snow covered area in spring for HKH region indicates a declining trend (−1.04±0.97%). The amount of annual snowfall is correlated with annual seasonal snow cover for the western Himalaya, indicating that changes in snow cover are primarily due to interannual variations in circulation patterns. Snow cover trends over a decade were also found to vary across seasonally and the region. Snow cover trends for western HKH are positive for all seasons. In central HKH the trend is positive (+15.53±5.69%) in autumn and negative (−03.68&plusmn3.01) in winter. In eastern HKH the trend is positive in summer (+3.35±1.62%) and autumn (+7.74±5.84%). The eastern and western region of HKH has an increasing trend of 10% to 12%, while the central region has a declining trend of 12% to 14% in the decade between 2000 and 2010. Snow cover depletion curve plotted for the hydrological year 2000–2001 reveal peaks in the month of February with subsidiary peaks observed in November and December in all three regions of the HKH.

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Height dependence of the tendency for reduction in seasonal snow cover in the Himalaya and the Tibetan Plateau region, 1966–2001

Annals of Glaciology ◽

10.3189/172756406781811989 ◽

2006 ◽

Vol 43 ◽

pp. 369-377 ◽

Cited By ~ 17

Author(s):

Kunio Rikiishi ◽

Haruka Nakasato

Keyword(s):

Tibetan Plateau ◽

Snow Cover ◽

The Tibetan Plateau ◽

Plateau Region ◽

Seasonal Snow ◽

Snow Covered Area ◽

Covered Area ◽

Height Dependence ◽

Seasonal Snow Cover ◽

The Himalaya

AbstractThe dataset of Northern Hemisphere EASE-Grid Weekly Snow Cover and Sea Ice Extent for the period October 1966-July 2001 is analyzed to examine the height dependence of declining tendencies of seasonal snow cover in the Himalaya and the Tibetan Plateau region (25−45˚ N, 70−110˚E). It is found that the annual mean snow-covered area is decreasing in the Himalaya/Tibet region at a rate of ∼ 1 % a−1, implying that the mean snow-covered area has decreased by one-third from 1966 to 2001. The rate of decrease is largest (1.6%) at the lowest elevations (0−500 m). On the other hand, the length of the snow-cover season is declining at all elevations, with the greatest rate of decline in the 4000−6000 m height range. On the Tibetan Plateau (∼4000−6000 m a.s.l.), the length of the snow-cover season has decreased by 23 days, and the end date for snow cover has advanced by 41 days over this 35 year period. These rates might be somewhat overestimated by the binary definition of snow cover on satellite images. It is likely that the reduction of the snow surface albedo by deposition of Asian dust and anthropogenic aerosols may be at least partly responsible for earlier snowmelt.

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Estimated seasonal snow cover and snowfall in Japan

Annals of Glaciology ◽

10.1017/s0260305500011460 ◽

1993 ◽

Vol 18 ◽

pp. 179-184

Author(s):

Tsutomu Nakamura ◽

Osamu Abe

Keyword(s):

Snow Cover ◽

Snow Depth ◽

Snow Water Equivalent ◽

Heavy Snowfall ◽

Seasonal Snow ◽

Snow Covered Area ◽

Covered Area ◽

Prone Area ◽

Snow Water ◽

Seasonal Snow Cover

The average amounts of seasonal snow cover and snowfall in Japan were calculated as 7.9 × 1013kg and 1.2 × 1014kg, respectively. The mass of seasonal snow cover of a heavy-snowfall winter, 1980–81 (56-Gosetsu), was calculated as 1.3 × 1014kg. The amount of 7.9 × 1013kg was converted to water equivalent of 230 mm on the whole snow-covered area, including snow-prone area. A mean of 370 mm in snow water equivalent was calculated for the snow area where mean snow depth on the ground was more than 10 cm.

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Estimated seasonal snow cover and snowfall in Japan

Annals of Glaciology ◽

10.3189/s0260305500011460 ◽

1993 ◽

Vol 18 ◽

pp. 179-184

Author(s):

Tsutomu Nakamura ◽

Osamu Abe

Keyword(s):

Snow Cover ◽

Snow Depth ◽

Snow Water Equivalent ◽

Heavy Snowfall ◽

Seasonal Snow ◽

Snow Covered Area ◽

Covered Area ◽

Prone Area ◽

Snow Water ◽

Seasonal Snow Cover

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Spatial Variability of Shortwave Irradiance for Snowmelt in Forests

Journal of Hydrometeorology ◽

10.1175/2008jhm867.1 ◽

2008 ◽

Vol 9 (6) ◽

pp. 1482-1490 ◽

Cited By ~ 33

Author(s):

John Pomeroy ◽

Chad Ellis ◽

Aled Rowlands ◽

Richard Essery ◽

Janet Hardy ◽

...

Keyword(s):

Spatial Variability ◽

Spatial Variation ◽

Snow Cover ◽

Boreal Forests ◽

Stand Structure ◽

Snow Accumulation ◽

Snow Covered Area ◽

Covered Area ◽

Depletion Curve ◽

Natural Snow

Abstract The spatial variation of melt energy can influence snow cover depletion rates and in turn be influenced by the spatial variability of shortwave irradiance to snow. The spatial variability of shortwave irradiance during melt under uniform and discontinuous evergreen canopies at a U.S. Rocky Mountains site was measured, analyzed, and then compared to observations from mountain and boreal forests in Canada. All observations used arrays of pyranometers randomly spaced under evergreen canopies of varying structure and latitude. The spatial variability of irradiance for both overcast and clear conditions declined dramatically, as the sample averaging interval increased from minutes to 1 day. At daily averaging intervals, there was little influence of cloudiness on the variability of subcanopy irradiance; instead, it was dominated by stand structure. The spatial variability of irradiance on daily intervals was higher for the discontinuous canopies, but it did not scale reliably with canopy sky view. The spatial variation in irradiance resulted in a coefficient of variation of melt energy of 0.23 for the set of U.S. and Canadian stands. This variability in melt energy smoothed the snow-covered area depletion curve in a distributed melt simulation, thereby lengthening the duration of melt by 20%. This is consistent with observed natural snow cover depletion curves and shows that variations in melt energy and snow accumulation can influence snow-covered area depletion under forest canopies.

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Distribution of seasonal snow cover in central and western Himalaya

Annals of Glaciology ◽

10.3189/172756410791386445 ◽

2010 ◽

Vol 51 (54) ◽

pp. 123-128 ◽

Cited By ~ 47

Author(s):

Anil V. Kulkarni ◽

B.P. Rathore ◽

S.K. Singh ◽

Ajai

Keyword(s):

Snow Cover ◽

Western Himalaya ◽

Snow Accumulation ◽

Wide Field ◽

Seasonal Snow ◽

Snow Line ◽

Field Sensor ◽

Normalized Difference Snow Index ◽

The Individual ◽

Seasonal Snow Cover

AbstractIndian rivers originating in the Himalaya depend on seasonal snow-cover melt during crucial summer months. The seasonal snow cover was monitored using Advanced Wide Field Sensor (AWiFS) data of the Indian Remote Sensing Satellite (IRS) and using the Normalized Difference Snow Index (NDSI) algorithm. The investigation was carried out for a period of 3 years (2004/05, 2005/06 and 2006/07) between October and June. A total of 28 sub-basins of the Ganga and Indus river basins were monitored at intervals of 5 or 10 days. Approximately 1500 AWiFS scenes were analyzed. A combination of area–altitude distribution and snow map was used to estimate the distribution of snow cover in altitude zones for the individual basins and for the western and central Himalaya. Hypsographic curve and snow-free area was used to estimate monthly snow-line elevation. The lowest snow-line altitude in the winters of 2004/05, 2005/06 and 2006/07 was observed at 2480 ma.s.l. on 25 February 2005. In Ravi basin for the year 2004/05, snow accumulation and ablation were continuous processes throughout the winter. Even in the middle of winter, the snow area was reduced from 90% to 55%. Similar trends were observed for 2005/06 and 2007/08. In Bhaga basin, snowmelt was observed in the early part of the winter, i.e. in December, and no significant melting was observed between January and April.

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Adaptation to climate change in Kazakhstan using data from space monitoring of snowmelt

E3S Web of Conferences ◽

10.1051/e3sconf/202022303006 ◽

2020 ◽

Vol 223 ◽

pp. 03006

Author(s):

Aknur Zholdasbek ◽

Azamat Kauazov

Keyword(s):

Climate Change ◽

Snow Cover ◽

Temporal Distribution ◽

Snow Melting ◽

Adaptation To Climate Change ◽

Snow Covered Area ◽

Covered Area ◽

Using Data ◽

Seasonal Snow Cover

The present article is concerned with the applied aspects of applying the results of space monitoring of snow cover, in particular, it is proposed to present the results of the analysis in the form of specialized bulletins. The purpose of this publication is to present the available results of space monitoring of snow cover in Kazakhstan as an element of adaptation to climate change. A three-level system of space monitoring of snow cover is proposed, which includes three technological complexes: operational mapping of snow cover boundaries; monitoring of seasonal snow cover dynamics; analysis of long-term snow cover dynamics. A map of snow melting in Kazakhstan in 2020, the dynamics of long-term changes of snow covered area, as well as methods for analyzing the spatial- temporal distribution of snow cover and formats of special bulletins are presented. It is most appropriate to present the results of space monitoring of snow cover in a complex, maximally generalized form (product). The results of the work can be applied in the scientific, industrial and educational spheres to adapt and increase resistance.

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Albedo model for shallow prairie snow covers

Canadian Journal of Earth Sciences ◽

10.1139/e87-168 ◽

1987 ◽

Vol 24 (9) ◽

pp. 1760-1768 ◽

Cited By ~ 43

Author(s):

D. M. Gray ◽

P. G. Landine

Keyword(s):

Standard Deviation ◽

Snow Cover ◽

Empirical Relationship ◽

Global Radiation ◽

Net Radiation ◽

Seasonal Snow ◽

Depletion Curve ◽

Radiation Maximum ◽

Deep Depth ◽

Seasonal Snow Cover

A model for simulating the decrease in albedo of melting prairie snow covers is presented. Its application for calculating net radiation and establishing the time of melt is demonstrated. It is expected the routine will find use in operational systems for synthesizing and forecasting streamflow runoff from snowmelt.The model is based on point and aerial observations of incoming and reflected global radiation taken from February 1 to the end of ablation of the seasonal snow cover, over a 14 year period, in the open grassland area of western Canada. For complete snow covers not subject to frequent melt events, the albedo-depletion curve is approximated by three line segments of constant slope describing the periods of (1) premelt—the months preceding the occurrence of "active" melt; (2) melt—the period of rapid ablation that leads to the disappearance of the seasonal snow cover, and (3) postmelt—the days following melt.An algorithm of the model is developed and procedures for defining the start of melt and albedo depletion from daily inputs of net radiation, maximum air temperature, and snow-cover and snowfall depths are described. Data are presented that demon strate close agreement between simulated and measured albedo-depletion curves for "deep" (depth > 25 cm) and "shallow" (depth ≤25 cm) snow covers. The mean difference between simulated and measured albedo on 74 days of melt over 7 years of record was calculated to be −0.0007 with a standard deviation of 0.17.The model is applied for calculating daily net radiation during the melt period. This analysis makes use of an empirical relationship to estimate net radiation from the clear-sky insolation, sunshine hours, and simulated albedo. Comparison of the differences between simulated and measured values for 62 days of melt gave a mean and standard deviation of 0.49 and 2.05 MJ/(m2∙d), respectively.

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Long-term spatio-temporal seasonal snow cover variability in the Hindu Kush Himalaya

10.5194/egusphere-egu21-14693 ◽

2021 ◽

Author(s):

Kathrin Naegeli ◽

Nils Rietze ◽

Jörg Franke ◽

Martin Stengel ◽

Christoph Neuhaus ◽

...

Keyword(s):

High Resolution ◽

Snow Cover ◽

Precipitation Pattern ◽

Snow Cover Area ◽

Seasonal Snow ◽

Hindu Kush ◽

Spatio Temporal ◽

Area Percentage ◽

Seasonal Snow Cover

The Hindu Kush Himalaya (HKH), the worlds &#8216;water tower&#8217;, contains the largest volume of snow and ice outside of the polar ice sheets and is the headwater area of Asia&#8217;s largest rivers. Due to the complex topography and its great spatial extent the HKH is characterised by variable temperature and precipitation pattern and thus exhibits large heterogeneity in the presence of seasonal snow cover (SSC). Previous studies usually focused on regional studies of snow cover area percentage or the influence of snow melt on the local hydrological system. Here we present a systematic overview of spatio-temporal SSC variability of the entire HKH region on a climate relevant time scale (four decades).Our results are based on Advanced Very High Resolution (AVHRR) data, collected onboard the polar orbiting satellites NOAA-7 to -19, providing daily, global imagery at a spatial resolution of 5 km since 1982 up to today. This unique dataset is exceptionally valuable to derive pixel-based SSC information using a Normalised Difference Snow Cover (NDSI) approach including additional thresholds related to topography and land cover, and developed in the frame of ESA CCI+ snow. &#160;Calibrated and geocoded reflectance data and a consistent cloud mask, derived in the ESA CCI cloud project, are used. A temporal gap-filling was applied to mitigate the influence of clouds. Reference snow maps from high-resolution optical satellite data as well as in-situ station data were used to validate the time series.The dataset allows analysis of the state and trends of SSC at regional and sub-regional level. We thus investigated spatio-temporal evolution and long-term variability of SSC for the entire HKH as well as for 14 hydrological basins. We find large spatial difference in the amount of SSC depending on the regional elevation and precipitation characteristics. Furthermore, we investigate SSC phenology, which is directly linked to climate change and thus of high relevance for seasonal water storage and mountain streamflow. Our analysis indicates a significant decline in snow cover area percentage (SCA %) during warm and dry summer month and a decreasing tendency from high winter through spring to early summer. At the hydrological basin level, no significant long-term trend was detected, however, both western and central basins indicate a decrease in SCA % and generally the latest years are strongly negative. Moreover, we examine SCA % anomalies at the highest available temporal frequency (daily information) and reveal an overall shortening of the SSC occurrence and a general decrease of SSC extent in the HKH region.

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Areal Extent of Seasonal Snow Cover in a Changed Climate

Hydrology Research ◽

10.2166/nh.1994.0006 ◽

1994 ◽

Vol 25 (4) ◽

pp. 233-246 ◽

Cited By ~ 20

Author(s):

A. Rango ◽

J. Martinec

Keyword(s):

Snow Cover ◽

Climate Models ◽

Change Scenario ◽

Rio Grande Basin ◽

Snow Covered Area ◽

Covered Area ◽

Snow Cover Extent ◽

Speed Up ◽

Seasonal Snow Cover ◽

Runoff Model

In mountain snow basins, a change in climate will likely cause a change in the basin snow cover extent. A procedure for evaluating whether a given climate change scenario will speed up or slow down the seasonal decrease of snow covered area is outlined with hypothetical examples for a simple basin. This procedure has two main purposes. First, it can be used to generate snow covered area data in a new climate for input to runoff models such as the Snowmelt-Runoff Model (SRM). Second, it could potentially be used to provide input to climate models that require knowledge of the land area covered by snow at a given time. A computer program is now operational for use on real basins and is demonstrated on the Rio Grande basin in Colorado and the Illecillewaet River basin in British Columbia.

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