scholarly journals Projected Changes in Snow Water Equivalent over the Tibetan Plateau under Global Warming of 1.5° and 2°C

2020 ◽  
Vol 33 (12) ◽  
pp. 5141-5154
Author(s):  
Qinglong You ◽  
Fangying Wu ◽  
Hongguo Wang ◽  
Zhihong Jiang ◽  
Nick Pepin ◽  
...  
Keyword(s):  
Global Warming ◽  
Tibetan Plateau ◽  
Snow Water Equivalent ◽  
Coupled Model ◽  
The Tibetan Plateau ◽  
Model Simulations ◽  
The Future ◽  
Snow Water ◽  
Positive Correlations ◽  
Projected Changes

AbstractSnow water equivalent (SWE) is a critical parameter for characterizing snowpack, which has a direct influence on the hydrological cycle, especially over high terrain. In this study, SWE from 18 coupled model simulations from phase 5 of the Coupled Model Intercomparison Project (CMIP5) is validated against the Canadian Sea Ice and Snow Evolution Network (CanSISE) SWE. The model simulations under RCP8.5 and RCP4.5 are employed to investigate projected changes in spring/winter SWE over the Tibetan Plateau (TP) under global warming of 1.5° and 2°C. Most CMIP5 models overestimate the CanSISE SWE. A decrease in mean spring/winter SWE for both RCPs over most regions of the TP is predicted in the future, with most significant reductions over the western TP, consistent with pronounced warming in that region. This is supported by strong positive correlations between SWE and mean temperature in the future in both seasons. Compared with the preindustrial period, spring/winter SWE over the TP under global warming of 1.5° and 2°C will reduce significantly, at faster rates than over China as a whole and the Northern Hemisphere. SWE changes over the TP do not show a simple elevation dependency under global warming of 1.5° and 2°C, with maximum changes in the elevation band of 4000–4500 m. Moreover, there are also strong positive correlations between projected SWE and historical mean SWE, indicating that the initial conditions of SWE are an important parameter of future SWE under specific global warming scenarios.

Evaluation and Intercomparison of Multiple Snow Water Equivalent Products over the Tibetan Plateau

2019 ◽  
Vol 20 (10) ◽  
pp. 2043-2055 ◽  
Author(s):  
Qingyun Bian ◽  
Zhongfeng Xu ◽  
Long Zhao ◽  
Yong-Fei Zhang ◽  
Hui Zheng ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Snow Water Equivalent ◽  
Climate Model ◽  
Asian Summer Monsoon ◽  
Accurate Estimation ◽  
The Tibetan Plateau ◽  
Seasonal Forecasts ◽  
Snow Condition ◽  
Snow Water

Abstract Snow cover affects the thermal conditions of the Tibetan Plateau through snow–albedo feedback and snowmelt, which, in turn, modulates the Asian summer monsoon climate. An accurate estimation of the snow condition on the Tibetan Plateau is therefore of great importance in both seasonal forecasts and climate studies. Estimation of snow water equivalent (SWE) over the Tibetan Plateau is challenging due to the high altitude, complex terrain, and insufficient in situ observations. Multiple SWE products derived from satellite estimates, reanalyses, regional climate model simulations, and land data assimilations are intercompared in terms of daily, seasonal, and annual variations and are then evaluated against in situ SWE observations. The results show a relatively consistent seasonal to interannual variability of the SWE estimates among the products. The discrepancies in magnitude are large, however, especially in winter and spring. Evaluation against in situ SWE observations indicates that none of these products is capable of accurately characterizing both the spatial pattern and temporal variations.

scholarly journals Projected 21st century changes in snow water equivalent over Northern Hemisphere landmasses from the CMIP5 model ensemble

2015 ◽  
Vol 9 (5) ◽  
pp. 1943-1953 ◽  
Author(s):  
H. X. Shi ◽  
C. H. Wang
Keyword(s):  
Northern Hemisphere ◽  
21St Century ◽  
Climate Models ◽  
Snow Water Equivalent ◽  
Global Climate ◽  
Coupled Model ◽  
Global Climate Models ◽  
The Tibetan Plateau ◽  
Model Ensemble ◽  
Snow Water

Abstract. Changes in snow water equivalent (SWE) over Northern Hemisphere (NH) landmasses are investigated for the early (2016–2035), middle (2046–2065) and late (2080–2099) 21st century using a multi-model ensemble from 20 global climate models from the Coupled Model Intercomparison Project Phase 5 (CMIP5). The multi-model ensemble was found to provide a realistic estimate of observed NH mean winter SWE compared to the GlobSnow product. The multi-model ensemble projects significant decreases in SWE over the 21st century for most regions of the NH for representative concentration pathways (RCPs) 2.6, 4.5 and 8.5. This decrease is particularly evident over the Tibetan Plateau and North America. The only region with projected increases is eastern Siberia. Projected reductions in mean annual SWE exhibit a latitudinal gradient with the largest relative changes over lower latitudes. SWE is projected to undergo the largest decreases in the spring period where it is most strongly negatively correlated with air temperature. The reduction in snowfall amount from warming is shown to be the main contributor to projected changes in SWE during September to May over the NH.

scholarly journals The Spatiotemporal Patterns and Interrelationships of Snow Cover and Climate Change in Tianshan Mountains

Water ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 404
Author(s):  
Tong Heng ◽  
Xinlin He ◽  
Lili Yang ◽  
Jiawen Yu ◽  
Yulin Yang ◽  
...  
Keyword(s):  
Snow Cover ◽  
Snow Water Equivalent ◽  
Warming Trend ◽  
Tianshan Mountains ◽  
Spatiotemporal Patterns ◽  
Tianshan Mountain ◽  
Mountainous Areas ◽  
The Future ◽  
Snow Water ◽  
Nighttime Warming

To reveal the spatiotemporal patterns of the asymmetry in the Tianshan mountains’ climatic warming, in this study, we analyzed climate and MODIS snow cover data (2001–2019). The change trends of asymmetrical warming, snow depth (SD), snow coverage percentage (SCP), snow cover days (SCD) and snow water equivalent (SWE) in the Tianshan mountains were quantitatively determined, and the influence of asymmetrical warming on the snow cover activity of the Tianshan mountains were discussed. The results showed that the nighttime warming rate (0.10 °C per decade) was greater than the daytime, and that the asymmetrical warming trend may accelerate in the future. The SCP of Tianshan mountain has reduced by 0.9%. This means that for each 0.1 °C increase in temperature, the area of snow cover will reduce by 5.9 km2. About 60% of the region’s daytime warming was positively related to SD and SWE, and about 48% of the region’s nighttime warming was negatively related to SD and SWE. Temperature increases were concentrated mainly in the Pamir Plateau southwest of Tianshan at high altitudes and in the Turpan and Hami basins in the east. In the future, the western and eastern mountainous areas of the Tianshan will continue to show a warming trend, while the central mountainous areas of the Tianshan mountains will mainly show a cooling trend.

scholarly journals Spatial-Temporal Patterns and Controls of Evapotranspiration across the Tibetan Plateau (2000–2012)

2017 ◽  
Vol 2017 ◽  
pp. 1-12 ◽  
Author(s):  
Hao Zhang ◽  
Jian Sun ◽  
Junnan Xiong
Keyword(s):  
Tibetan Plateau ◽  
Environmental Factors ◽  
Vegetation Type ◽  
Middle Part ◽  
Rate Of Change ◽  
Ecological Indicator ◽  
The Tibetan Plateau ◽  
Grassland Ecosystems ◽  
Key Factor ◽  
Positive Correlations

Evapotranspiration (ET) is a key factor to further our understanding of climate change processes, especially on the Tibetan Plateau, which is sensitive to global change. Herein, the spatial patterns of ET are examined, and the effects of environmental factors on ET at different scales are explored from the years 2000 to 2012. The results indicated that a steady trend in ET was detected over the past decade. Meanwhile, the spatial distribution shows an increase of ET from the northwest to the southeast, and the rate of change in ET is lower in the middle part of the Tibetan Plateau. Besides, the positive effect of radiation on ET existed mainly in the southwest. Based on the environment gradient transects, the ET had positive correlations with temperature (R>0.85, p<0.0001), precipitation (R > 0.89, p < 0.0001), and NDVI (R > 0.75, p < 0.0001), but a negative correlation between ET and radiation (R = 0.76, p < 0.0001) was observed. We also found that the relationships between environmental factors and ET differed in the different grassland ecosystems, which indicated that vegetation type is one factor that can affect ET. Generally, the results indicate that ET can serve as a valuable ecological indicator.

Snowpack energy balance and changes in the frequency and extremity of rain-on-snow events in the warming climate

2021 ◽  
Author(s):  
Ondrej Hotovy ◽  
Michal Jenicek
Keyword(s):  
Energy Balance ◽  
Air Temperature ◽  
Snow Water Equivalent ◽  
Hydrological Cycle ◽  
Winter Season ◽  
Catchment Scale ◽  
The Future ◽  
Snow Water ◽  
The Impact ◽  
Catchment Runoff

&lt;p&gt;Seasonal snowpack significantly influences the catchment runoff and thus represents an important input for the hydrological cycle. Changes in the precipitation distribution and intensity, as well as a shift from snowfall to rain is expected in the future due to climate changes. As a result, rain-on-snow events, which are considered to be one of the main causes of floods in winter and spring, may occur more frequently. Heat from liquid precipitation constitutes one of the snowpack energy balance components. Consequently, snowmelt and runoff may be strongly affected by these temperature and precipitation changes.&lt;/p&gt;&lt;p&gt;The objective of this study is 1) to evaluate the frequency, inter-annual variability and extremity of rain-on-snow events in the past based on existing measurements together with an analysis of changes in the snowpack energy balance, and 2) to simulate the effect of predicted increase in air temperature on the occurrence of rain-on-snow events in the future. We selected 40 near-natural mountain catchments in Czechia with significant snow influence on runoff and with available long-time series (&gt;35 years) of daily hydrological and meteorological variables. A semi-distributed conceptual model, HBV-light, was used to simulate the individual components of the water cycle at a catchment scale. The model was calibrated for each of study catchments by using 100 calibration trials which resulted in respective number of optimized parameter sets. The model performance was evaluated against observed runoff and snow water equivalent. Rain-on-snow events definition by threshold values for air temperature, snow depth, rain intensity and snow water equivalent decrease allowed us to analyze inter-annual variations and trends in rain-on-snow events during the study period 1965-2019 and to explain the role of different catchment attributes.&lt;/p&gt;&lt;p&gt;The preliminary results show that a significant change of rain-on-snow events related to increasing air temperature is not clearly evident. Since both air temperature and elevation seem to be an important rain-on-snow drivers, there is an increasing rain-on-snow events occurrence during winter season due to a decrease in snowfall fraction. In contrast, a decrease in total number of events was observed due to the shortening of the period with existing snow cover on the ground. Modelling approach also opened further questions related to model structure and parameterization, specifically how individual model procedures and parameters represent the real natural processes. To understand potential model artefacts might be important when using HBV or similar bucket-type models for impact studies, such as modelling the impact of climate change on catchment runoff.&lt;/p&gt;

ASSESSMENT OF CHANGES IN THE CHARACTERISTICS OF THE WATER, SNOW AND ICE REGIMES IN THE BASINS OF THE SMALL NORTHERN DVINA RIVER UNDER MODERN CONDITIONS AND THEIR POSSIBLE CHANGES IN THE FUTURE

2021 ◽  
pp. 117-127
Author(s):  
M. V. GEORGIEVSKY ◽  
◽  
N. I. GOROSHKOVA ◽  
V. A. KHOMYAKOVA ◽  
A. V. STRIZHENOK
Keyword(s):  
Snow Cover ◽  
Climate Warming ◽  
Snow Water Equivalent ◽  
Winter Precipitation ◽  
Spring Runoff ◽  
The Future ◽  
Snow Water ◽  
Project Data ◽  
The Impact ◽  
Slight Downward Trend

The article presents an analysis of the impact of climate change on the main characteristics of ice phenomena, snow cover and the water regime in the Small Northern Dvina River basin occurring in recent decades. Recently, a significant climate warming has been observed in the basin. As a result, winters are getting warmer and shorter. There is also an increase in winter precipitation and the number of thaws. Climate warming directly affects the duration of snow cover, which decreases both due to the later formation and to the earlier destruction of snow. There is also a slight downward trend in the annual values of the maximum snow water equivalent, which may be the result of an increase in the number of thaws in winter, when a part of the snow cover melts contributing to the winter river runoff. The analysis of the main characteristics of the ice cover on the rivers of the studied basin shows that their changes are similarly to changes in the snow cover: there is a reduction in the freeze-up period due to its later formation and earlier complete destruction. The maximum ice thickness on the rivers of the basin also tends to decrease. There is an increase in winter and a decrease in spring runoff. Predictive estimates of changes in the observed trends in the future are presented in the fi nal part of the article based on the CMIP5 project data.

Melting Ice Rivers

2012 ◽  
Author(s):  
Cheryl Colopy
Keyword(s):  
Global Warming ◽  
Tibetan Plateau ◽  
The Netherlands ◽  
Sea Level ◽  
The Tibetan Plateau ◽  
Mount Everest ◽  
The Past ◽  
The North ◽  
The World ◽  
The Government

From a remote outpost of global warming, a summons crackles over a two-way radio several times a week: . . . Kathmandu, Tsho Rolpa! Babar Mahal, Tsho Rolpa! Kathmandu, Tsho Rolpa! Babar Mahal, Tsho Rolpa! . . . In a little brick building on the lip of a frigid gray lake fifteen thousand feet above sea level, Ram Bahadur Khadka tries to rouse someone at Nepal’s Department of Hydrology and Meteorology in the Babar Mahal district of Kathmandu far below. When he finally succeeds and a voice crackles back to him, he reads off a series of measurements: lake levels, amounts of precipitation. A father and a farmer, Ram Bahadur is up here at this frigid outpost because the world is getting warmer. He and two colleagues rotate duty; usually two of them live here at any given time, in unkempt bachelor quarters near the roof of the world. Mount Everest is three valleys to the east, only about twenty miles as the crow flies. The Tibetan plateau is just over the mountains to the north. The men stay for four months at a stretch before walking down several days to reach a road and board a bus to go home and visit their families. For the past six years each has received five thousand rupees per month from the government—about $70—for his labors. The cold, murky lake some fifty yards away from the post used to be solid ice. Called Tsho Rolpa, it’s at the bottom of the Trakarding Glacier on the border between Tibet and Nepal. The Trakarding has been receding since at least 1960, leaving the lake at its foot. It’s retreating about 200 feet each year. Tsho Rolpa was once just a pond atop the glacier. Now it’s half a kilometer wide and three and a half kilometers long; upward of a hundred million cubic meters of icy water are trapped behind a heap of rock the glacier deposited as it flowed down and then retreated. The Netherlands helped Nepal carve out a trench through that heap of rock to allow some of the lake’s water to drain into the Rolwaling River.

Decomposition of Future Moisture Flux Changes over the Tibetan Plateau Projected by Global and Regional Climate Models

2019 ◽  
Vol 32 (20) ◽  
pp. 7037-7053
Author(s):  
Hongwen Zhang ◽  
Yanhong Gao ◽  
Jianwei Xu ◽  
Yu Xu ◽  
Yingsha Jiang
Keyword(s):  
Tibetan Plateau ◽  
Climate Model ◽  
Dynamical Downscaling ◽  
Regional Climate ◽  
Moisture Flux ◽  
Historical Period ◽  
The Tibetan Plateau ◽  
Dynamic Component ◽  
Coarse Resolution ◽  
The Future

Abstract To meet the requirement of high-resolution datasets for many applications, a dynamical downscaling approach using a regional climate model (the WRF Model) driven by a global climate model (CCSM4) has been adopted. This study focuses on projections of future moisture flux changes over the Tibetan Plateau (TP). First, the downscaling results for the historical period (1980–2005) are evaluated for precipitation P, evaporation E, and precipitation minus evaporation P − E against Global Land Data Assimilation System (GLDAS) data. The mechanism of P − E changes is analyzed by decomposition into dynamic, thermodynamic, and transient eddy components. Whether the historical period changes and mechanisms continue into the future (2010–2100) is investigated using the WRF and CCSM model projections under the RCP4.5 and RCP8.5 scenarios. Compared with coarse-resolution forcing, downscaling was found to better reproduce the historical spatial patterns and seasonal mean of annual average P, E, and P − E over the TP. WRF projects a diverse spatial variation of P − E changes, with an increase in the northern TP and a decrease in the southern TP, compared with the uniform increase in CCSM. The dynamic component dominates P − E changes for the historical period in both the CCSM and WRF projections. In the future, however, the thermodynamic component in CCSM dominates P − E changes under RCP4.5 and RCP8.5 from the near-term (2010–39) to the long-term (2070–99) future. Unlike the CCSM projections, the WRF projections reproduce the mechanism seen in the historical period—that is, the dynamic component dominates P − E changes. Furthermore, future P − E changes in the dynamical downscaling are less sensitive to warming than its coarse-resolution forcing.

scholarly journals Projections for the changes in growing season length of tree-ring formation on the Tibetan Plateau based on CMIP5 model simulations

2017 ◽  
Vol 62 (4) ◽  
pp. 631-641 ◽  
Author(s):  
Minhui He ◽  
Bao Yang ◽  
Vladimir Shishov ◽  
Sergio Rossi ◽  
Achim Bräuning ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Tree Ring ◽  
Growing Season ◽  
Ring Formation ◽  
The Tibetan Plateau ◽  
Cmip5 Model ◽  
Season Length ◽  
Model Simulations ◽  
Growing Season Length
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