Assessing Snow Phenology over the Large Part of Eurasia Using Satellite Observations from 2000 to 2016

Snow plays an important role in meteorological, hydrological and ecological processes, and snow phenology variation is critical for improved understanding of climate feedback on snow cover. The main purpose of the study is to explore spatial-temporal changes and variabilities of the extent, timing and duration, as well as phenology of seasonal snow cover across the large part of Eurasia from 2000 through 2016 using a Moderate Resolution Imaging Spectroradiometer (MODIS) cloud-free snow product produced in this study. The results indicate that there are no significant positive or negative interannual trends of snow cover extent (SCE) from 2000 to 2016, but there are large seasonal differences. SCE shows a significant negative trend in spring (p = 0.01) and a positive trend in winter. The stable snow cover areas accounting for 78.8% of the large part of Eurasia, are mainly located north of latitude 45° N and in the mountainous areas. In this stable area, the number of snow-covered days is significantly increasing (p < 0.05) in 6.4% of the region and decreasing in 9.1% of the region, with the decreasing areas being mainly located in high altitude mountain areas and the increasing area occurring mainly in the ephemeral snow cover areas of northeastern and southern China. In central Siberia, Pamir and the Tibetan Plateau, the snow onset date tends to be delayed while the end date is becoming earlier from 2000 to 2016. While in the relatively low altitude plain areas, such as the West Siberian Plain and the Eastern European Plain region, the snow onset date is tending to advance, the end date tends to be delayed, but the increase is not significant.

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Climate change in the High Mountain Asia simulated with CMIP6 models

10.5194/egusphere-egu21-8365 ◽

2021 ◽

Author(s):

Mickaël Lalande ◽

Martin Ménégoz ◽

Gerhard Krinner

Keyword(s):

High Resolution ◽

Snow Cover ◽

Climate Models ◽

Global Climate Models ◽

Cold Bias ◽

High Mountain ◽

The Tibetan Plateau ◽

Near Surface ◽

Model Biases ◽

Snow Cover Extent

<p>The High Mountains of Asia (HMA) region and the Tibetan Plateau (TP), with an average altitude of 4000 m, are hosting the third largest reservoir of glaciers and snow after the two polar ice caps, and are at the origin of strong orographic precipitation. Climate studies over HMA are related to serious challenges concerning the exposure of human infrastructures to natural hazards and the water resources for agriculture, drinking water, and hydroelectricity to whom several hundred million inhabitants of the Indian subcontinent are depending. However, climate variables such as temperature, precipitation, and snow cover are poorly described by global climate models because their coarse resolution is not adapted to the rugged topography of this region. Since the first CMIP exercises, a cold model bias has been identified in this region, however, its attribution is not obvious and may be different from one model to another. Our study focuses on a multi-model comparison of the CMIP6 simulations used to investigate the climate variability in this area to answer the next questions: (1) are the biases in HMA reduced in the new generation of climate models? (2) Do the model biases impact the simulated climate trends? (3) What are the links between the model biases in temperature, precipitation, and snow cover extent? (4) Which climate trajectories can be projected in this area until 2100? An analysis of 27 models over 1979-2014 still show a cold bias in near-surface air temperature over the HMA and TP reaching an annual value of -2.0 &#176;C (&#177; 3.2 &#176;C), associated with an over-extended relative snow cover extent of 53 % (&#177; 62 %), and a relative excess of precipitation of 139 % (&#177; 38 %), knowing that the precipitation biases are uncertain because of the undercatch of solid precipitation in observations. Model biases and trends do not show any clear links, suggesting that biased models should not be excluded in trend and projections analysis, although non-linear effects related to lagged snow cover feedbacks could be expected. On average over 2081-2100 with respect to 1995-2014, for the scenarios SSP126, SSP245, SSP370, and SSP585, the 9 available models shows respectively an increase in annual temperature of 1.9 &#176;C (&#177; 0.5 &#176;C), 3.4 &#176;C (&#177; 0.7 &#176;C), 5.2 &#176;C (&#177; 1.2 &#176;C), and 6.6 &#176;C (&#177; 1.5 &#176;C); a relative decrease in the snow cover extent of 10 % (&#177; 4.1 %), 19 % (&#177; 5 %), 29 % (&#177; 8 %), and 35 % (&#177; 9 %); and an increase in total precipitation of 9 % (&#177; 5 %), 13 % (&#177; 7 %), 19 % (&#177; 11 %), and 27 % (&#177; 13 %). Further analyses will be considered to investigate potential links between the biases at the surface and those at higher tropospheric levels as well as with the topography. The models based on high resolution do not perform better than the coarse-gridded ones, suggesting that the race to high resolution should be considered as a second priority after the developments of more realistic physical parameterizations.</p>

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Precipitation and snow cover in the Himalaya: from reanalysis to regional climate simulations

Hydrology and Earth System Sciences ◽

10.5194/hess-17-3921-2013 ◽

2013 ◽

Vol 17 (10) ◽

pp. 3921-3936 ◽

Cited By ~ 70

Author(s):

M. Ménégoz ◽

H. Gallée ◽

H. W. Jacobi

Keyword(s):

Snow Cover ◽

Climate Model ◽

Regional Climate ◽

Rain Gauge ◽

Snow Accumulation ◽

The Tibetan Plateau ◽

Monsoon Period ◽

Medium Range Weather Forecast ◽

Snow Cover Extent ◽

The Himalaya

Abstract. We applied a Regional Climate Model (RCM) to simulate precipitation and snow cover over the Himalaya, between March 2000 and December 2002. Due to its higher resolution, our model simulates a more realistic spatial variability of wind and precipitation than those of the reanalysis of the European Centre of Medium range Weather Forecast (ECMWF) used as lateral boundaries. In this region, we found very large discrepancies between the estimations of precipitation provided by reanalysis, rain gauges networks, satellite observations, and our RCM simulation. Our model clearly underestimates precipitation at the foothills of the Himalaya and in its eastern part. However, our simulation provides a first estimation of liquid and solid precipitation in high altitude areas, where satellite and rain gauge networks are not very reliable. During the two years of simulation, our model resembles the snow cover extent and duration quite accurately in these areas. Both snow accumulation and snow cover duration differ widely along the Himalaya: snowfall can occur during the whole year in western Himalaya, due to both summer monsoon and mid-latitude low pressure systems bringing moisture into this region. In Central Himalaya and on the Tibetan Plateau, a much more marked dry season occurs from October to March. Snow cover does not have a pronounced seasonal cycle in these regions, since it depends both on the quite variable duration of the monsoon and on the rare but possible occurrence of snowfall during the extra-monsoon period.

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Observing Snow Cover and Water Resource Changes in the High Mountain Asia Region in Comparison with Global Mountain Trends over 2000–2018

Remote Sensing ◽

10.3390/rs12233913 ◽

2020 ◽

Vol 12 (23) ◽

pp. 3913

Author(s):

Claudia Notarnicola

Keyword(s):

Water Resources ◽

Confidence Interval ◽

Snow Cover ◽

Water Storage ◽

High Mountain ◽

Global Level ◽

Total Water ◽

Mountain Areas ◽

Snow Cover Extent ◽

The Impact

The quantification of snow cover changes and of the related water resources in mountain areas has a key role for understanding the impact on several sectors such as ecosystem services, tourism and energy production. By using NASA-Moderate Resolution Imaging Spectroradiometer (MODIS) images from 2000 to 2018, this study analyzes changes in snow cover in the High Mountain Asia region and compares them with global mountain areas. Globally, snow cover extent and duration are declining with significant trends in around 78% of mountain areas, and the High Mountain Asia region follows similar trends in around 86% of the areas. As an example, Shaluli Shan area in China shows significant negative trends for both snow cover extent and duration, with −11.4% (confidence interval: −17.7%, −5.5%) and −47.3 days (confidence interval: −70.4 days, −24.4 days) at elevations >5500 m a.s.l. respectively. In spring, an earlier snowmelt of −13.5 days (confidence interval: −24.3 days, −2.0 days) in 4000–5500 m a.s.l. is detected. On the other side, Tien Shan area shows an earlier snow onset of −28.8 days (confidence interval: −44.3 days, −8.2 days) between 2500 and 4000 m a.s.l., governed by decreasing temperature and increasing snowfall. In the current analysis, the Tibetan Plateau shows no significant changes. Regarding water resources, by using Gravity Recovery and Climate Experiment (GRACE) data it was found that around 50% of areas in the High Mountain Asia region and 30% at global level are suffering from significant negative temporal trends of total water storage (including groundwater, soil moisture, surface water, snow, and ice) in the period 2002–2015. In the High Mountain Asia region, this negative trend involves around 54% of the areas during spring period, while at a global level this percentage lies between 25% and 30% for all seasons. Positive trends for water storage are detected in a maximum 10% of the areas in High Mountain Asia region and in around 20% of the areas at global level. Overall snow mass changes determine a significant contribution to the total water storage changes up to 30% of the areas in winter and spring time over 2002–2015.

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Dry-Season Snow Cover Losses in the Andes (18°–40°S) driven by Changes in Large-Scale Climate Modes

Scientific Reports ◽

10.1038/s41598-019-53486-7 ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 1

Author(s):

Raul R. Cordero ◽

Valentina Asencio ◽

Sarah Feron ◽

Alessandro Damiani ◽

Pedro J. Llanillo ◽

...

Keyword(s):

Snow Cover ◽

El Niño ◽

Large Scale ◽

El Nino ◽

Southern Oscillation ◽

Average Rate ◽

Dry Season ◽

Positive Trend ◽

Entire Study ◽

Snow Cover Extent

AbstractThe Andean snowpack is the primary source of water for many communities in South America. We have used Landsat imagery over the period 1986–2018 in order to assess the changes in the snow cover extent across a north-south transect of approximately 2,500 km (18°–40°S). Despite the significant interannual variability, here we show that the dry-season snow cover extent declined across the entire study area at an average rate of about −12% per decade. We also show that this decreasing trend is mainly driven by changes in the El Niño Southern Oscillation (ENSO), especially at latitudes lower than 34°S. At higher latitudes (34°–40°S), where the El Niño signal is weaker, snow cover losses appear to be also influenced by the poleward migration of the westerly winds associated with the positive trend in the Southern Annular Mode (SAM).

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Observed Relationship of Spring and Summer East Asian Rainfall with Winter and Spring Eurasian Snow

Journal of Climate ◽

10.1175/jcli4068.1 ◽

2007 ◽

Vol 20 (7) ◽

pp. 1285-1304 ◽

Cited By ~ 135

Author(s):

Renguang Wu ◽

Ben P. Kirtman

Keyword(s):

Tibetan Plateau ◽

Snow Cover ◽

Snow Depth ◽

Snow Water Equivalent ◽

Southern Oscillation ◽

Southern China ◽

Summer Rainfall ◽

Wave Pattern ◽

Summer Monsoon Rainfall ◽

The Tibetan Plateau

Abstract This study investigates the relationship between spring and summer rainfall in East Asia and the preceding winter and spring snow cover/depth over Eurasia, using station rainfall observations, satellite-observed snow cover, satellite-derived snow water equivalent, and station observations of the number of days of snow cover and snow depth. Correlation analysis shows that snow-depth anomalies can persist from winter to spring whereas snow cover anomalies cannot in most regions of Eurasia. Locally, snow cover and snow-depth anomalies in February are not related in most regions to the north of 50°N, but those anomalies in April display consistent year-to-year variations. The results suggest that the winter snow cover cannot properly represent all the effects of snow and it is necessary to separate the winter and spring snow cover in addressing the snow–monsoon relationship. Spring snow cover in western Siberia is positively correlated with spring rainfall in southern China. The circulation anomalies associated with the western Siberian spring snow cover variations show an apparent wave pattern over the eastern Atlantic through Europe and midlatitude Asia. Spring snow cover over the Tibetan Plateau shows a moderate positive correlation with spring rainfall in southern China. Analysis shows that this correlation includes El Niño–Southern Oscillation (ENSO) effects. In contrast to the Indian summer monsoon rainfall for which the ENSO interferes with the snow effects, the Tibetan Plateau snow cover and ENSO work cooperatively to enhance spring rainfall anomalies in southern China. In comparison, ENSO has larger impacts than the snow on spring rainfall in southern China.

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Modeled Northern Hemisphere Autumn and Winter Climate Responses to Realistic Tibetan Plateau and Mongolia Snow Anomalies

Journal of Climate ◽

10.1175/jcli-d-17-0117.1 ◽

2017 ◽

Vol 30 (23) ◽

pp. 9435-9454 ◽

Cited By ~ 10

Author(s):

Shizuo Liu ◽

Qigang Wu ◽

Xuejuan Ren ◽

Yonghong Yao ◽

Steven R. Schroeder ◽

...

Keyword(s):

Tibetan Plateau ◽

Snow Cover ◽

Snow Water Equivalent ◽

Feedback Mechanism ◽

The Tibetan Plateau ◽

Surface Cooling ◽

Sea Ice Extent ◽

Winter Climate ◽

Snow Cover Extent ◽

Autumn And Winter

Observational studies link a persistent dipole of autumn and winter snow cover anomalies over the Tibetan Plateau (TP) and Mongolia with winter Pacific–North American (PNA)-like atmospheric variations. This study investigates atmospheric responses to such snow forcings using multiple ensemble transient integrations of the CAM4 and CLM4.0 models. Model boundary conditions are based on climatological sea ice extent and sea surface temperature, and satellite observations of snow cover extent (SCE) and snow water equivalent (SWE) over the TP and Mongolia from October to March in 1997/98 (heavy TP and light Mongolia snow) and 1984/85 (light TP and heavy Mongolia snow), with model-derived SCE and SWE elsewhere. In various forcing experiments, the ensemble-mean difference between simulations with these two extreme snow states identifies local, distant, concurrent, and delayed climatic responses. The main atmospheric responses to a dipole of high TP and low Mongolia SCE persisting from October to March (versus the opposite extreme) are strong TP surface cooling, warming in the surrounding China and Mongolia region, and a winter positive PNA-like response. The localized response is maintained by persistent diabatic cooling or heating, and the remote PNA response results mainly from the increased horizontal eastward propagation of stationary Rossby wave energy due to persistent TP snow forcing and also a winter transient eddy feedback mechanism. With a less persistent dipole anomaly in autumn or winter only, local responses are similar depending on the specific anomalies, but the winter PNA-like response is nearly absent or noticeably reduced.

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Process-based analysis of relative contributions to the multi-model warming projection over East Asia

Climate Dynamics ◽

10.1007/s00382-020-05614-7 ◽

2021 ◽

Author(s):

Hanjie Fan ◽

Xiaoming Hu ◽

Song Yang ◽

Yong-Sang Choi ◽

Yoon-Kyoung Lee

Keyword(s):

Water Vapor ◽

East Asia ◽

Model Uncertainty ◽

Surface Albedo ◽

Southern China ◽

Climate Feedback ◽

Response Analysis ◽

Climate Projections ◽

The Tibetan Plateau ◽

Radiative Processes

AbstractClimate models predict that East Asia (EA) will be substantially warmer than the present despite large inter-model uncertainty. This study investigated the major sources of the climate projections and the inter-model uncertainty. Particularly, we decomposed the differences in surface temperatures between the historical and RCP8.5 runs from 26 CMIP5 into partial surface temperature changes due to individual radiative and non-radiative processes through the climate feedback-response analysis method. Results show that anthropogenic greenhouse forcing and subsequent water vapor feedback processes are primarily responsible for the surface warming over EA. Relatively more rapid warming over the snow/ice-covered area and southern China is due to feedback processes associated with surface albedo and cloud, respectively. The regional warming is, however, compensated by the surface non-radiative (sensible and latent heat) cooling. The inter-model projection uncertainty is substantially large over high latitudes and the Tibetan Plateau mainly due to surface albedo feedback. Again, this large uncertainty is partly suppressed by surface non-radiative cooling. Water vapor and cloud feedbacks are the secondary important sources of the projection uncertainty. Moreover, the contributions of greenhouse forcing and atmospheric dynamics to the projection uncertainty are found to be minor.

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Observed high-altitude warming and snow cover retreat over Tibet and the Himalayas enhanced by black carbon aerosols

Atmospheric Chemistry and Physics ◽

10.5194/acp-16-1303-2016 ◽

2016 ◽

Vol 16 (3) ◽

pp. 1303-1315 ◽

Cited By ~ 43

Author(s):

Y. Xu ◽

V. Ramanathan ◽

W. M. Washington

Keyword(s):

Tibetan Plateau ◽

High Altitude ◽

Snow Cover ◽

Black Carbon ◽

Global Climate Model ◽

Anthropogenic Factors ◽

Climate Projections ◽

The Tibetan Plateau ◽

Surface Warming ◽

Snow Cover Extent

Abstract. Himalayan mountain glaciers and the snowpack over the Tibetan Plateau provide the headwater of several major rivers in Asia. In situ observations of snow cover extent since the 1960s suggest that the snowpack in the region have retreated significantly, accompanied by a surface warming of 2–2.5 °C observed over the peak altitudes (5000 m). Using a high-resolution ocean–atmosphere global climate model and an observationally constrained black carbon (BC) aerosol forcing, we attribute the observed altitude dependence of the warming trends as well as the spatial pattern of reductions in snow depths and snow cover extent to various anthropogenic factors. At the Tibetan Plateau altitudes, the increase in atmospheric CO2 concentration exerted a warming of 1.7 °C, BC 1.3 °C where as cooling aerosols cause about 0.7 °C cooling, bringing the net simulated warming consistent with the anomalously large observed warming. We therefore conclude that BC together with CO2 has contributed to the snow retreat trends. In particular, BC increase is the major factor in the strong elevation dependence of the observed surface warming. The atmospheric warming by BC as well as its surface darkening of snow is coupled with the positive snow albedo feedbacks to account for the disproportionately large role of BC in high-elevation regions. These findings reveal that BC impact needs to be properly accounted for in future regional climate projections, in particular on high-altitude cryosphere.

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Precipitation and snow cover in the Himalaya: from reanalysis to regional climate simulations

Hydrology and Earth System Sciences Discussions ◽

10.5194/hessd-10-7651-2013 ◽

2013 ◽

Vol 10 (6) ◽

pp. 7651-7686 ◽

Cited By ~ 1

Author(s):

M. Ménégoz ◽

H. Gallée ◽

H. W. Jacobi

Keyword(s):

Snow Cover ◽

Climate Model ◽

Regional Climate ◽

Western Himalaya ◽

Rain Gauge ◽

Snow Accumulation ◽

The Tibetan Plateau ◽

Rain Gauges ◽

Snow Cover Extent ◽

The Himalaya

Abstract. We applied a Regional Climate Model (RCM) to simulate precipitation and snow cover over the Himalaya, between March 2000 to December 2002. Due to its higher resolution, our model simulates a more realistic spatial variability of wind and precipitation than those of the reanalysis used as boundary conditions. In this region, we found very large discrepancies between the estimations of precipitation provided by reanalysis, rain gauges networks, satellite observations, and our RCM simulation. Our model clearly underestimates precipitation at the foothills of the Himalaya and in its Eastern part. However, our simulation brings an interesting estimation of liquid and solid precipitation in high altitude areas, where satellite and rain gauge networks are few reliable. We found our model to simulate quite accurately the snow cover extent and duration for the two years of simulation in these areas. Snow accumulation and snow duration differ widely along the Himalaya: snowfall can occur during the whole year Western Himalaya, due to both summer monsoon and mid-latitude low pressure systems bringing moisture into this region. In Central Himalaya and on the Tibetan plateau, a much more marked dry season occurs from October to March. Snow cover does not have a well marked seasonal cycle in these regions, since it depends both on the quite variable duration of the monsoon and on the rare but possible occurrence of snowfall during the winter.

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Northern Hemisphere spring snow cover variability and change over 1922–2010 including an assessment of uncertainty

The Cryosphere Discussions ◽

10.5194/tcd-4-2483-2010 ◽

2010 ◽

Vol 4 (4) ◽

pp. 2483-2512

Author(s):

R. D. Brown ◽

D. A. Robinson

Keyword(s):

Snow Cover ◽

Northern Hemisphere ◽

Temperature Sensitivity ◽

Northern China ◽

The Tibetan Plateau ◽

Climate Data ◽

The Past ◽

The North ◽

Snow Cover Extent ◽

The North Atlantic Oscillation

Abstract. An update is provided of Northern Hemisphere (NH) spring (March, April) snow cover extent (SCE) over the 1922–2010 period incorporating the new climate data record (CDR) version of the NOAA weekly SCE dataset, with annual 95% confidence intervals estimates from regression analysis and intercomparison of multiple datasets. The uncertainty analysis indicated a 95% confidence interval in NH spring SCE of ±5–10% over the pre-satellite period and ±3–5% over the satellite era. The multi-dataset analysis showed there are larger uncertainties monitoring spring SCE over Eurasia (EUR) than North America (NA) due to the more complex regional character of the snow cover variability with the largest dataset uncertainty located over eastern Eurasia in a large region extending from the Tibetan Plateau across northern China. Trend analysis of the updated SCE series provided evidence that NH spring snow cover extent has undergone significant reductions over the past ~90 years and that the rate of decrease has accelerated over the past 40 years. The rate of decrease in March and April NH SCE over the 1970–2010 period is ~7–8 million km2 per 100 years which corresponds to an 8–11% decrease in NH March and April SCE respectively from pre-1970 values. In March, most of the change is being driven by Eurasia (NA trends are not significant) but both continents exhibit significant SCE reductions in April. The observed trends in SCE are consistent with recent warming trends over northern mid-latitude land areas with NH SCE exhibiting significant negative correlations to air temperature anomalies in March and April. The NH spring SCE-temperature sensitivity has remained relatively stable over the period of record although there is some evidence of contrasting changes in temperature sensitivity over both continents in April. There is evidence that changes in atmospheric circulation around 1980 involving the North Atlantic Oscillation and Scandinavian Pattern have contributed to reductions in March SCE over Eurasia.

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