The Tibetan Plateau cryosphere: Observations and model simulations for current status and recent changes

AbstractThis study explores how the termination of the mei-yu is dynamically linked to the westerlies impinging on the Tibetan Plateau. It is found that the mei-yu stage terminates when the maximum upper-tropospheric westerlies shift beyond the northern edge of the plateau, around 40°N. This termination is accompanied by the disappearance of tropospheric northerlies over northeastern China. The link between the transit of the jet axis across the northern edge of the plateau, the disappearance of northerlies, and termination of the mei-yu holds on a range of time scales from interannual through seasonal and pentad. Diagnostic analysis indicates that the weakening of the meridional moisture contrast and meridional wind convergence, mainly resulting from the disappearance of northerlies, causes the demise of the mei-yu front. The authors propose that the westerlies migrating north of the plateau and consequent weakening of the extratropical northerlies triggers the mei-yu termination. Model simulations are employed to test the causality between the jet and the orographic downstream northerlies by repositioning the northern edge of the plateau. As the plateau edge extends northward, orographic forcing on the westerlies strengthens, leading to persistent strong downstream northerlies and a prolonged mei-yu. Idealized simulations with a dry dynamical core further demonstrate the dynamical link between the weakening of orographically forced downstream northerlies with the positioning of the jet from south to north of the plateau. Changes in the magnitude of orographically forced stationary waves are proposed to explain why the downstream northerlies disappear when the jet axis migrates beyond the northern edge of the plateau.

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

Journal of Climate ◽

10.1175/jcli-d-19-0719.1 ◽

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.

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Summary and Current Status of the Research Models for the Tibetan Plateau Uplift

Open Journal of Nature Science ◽

10.12677/ojns.2016.42028 ◽

2016 ◽

Vol 04 (02) ◽

pp. 229-241

Author(s):

钦忠马

Keyword(s):

Tibetan Plateau ◽

Current Status ◽

The Tibetan Plateau ◽

Plateau Uplift ◽

Tibetan Plateau Uplift

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Development and evaluation of spectral nudging strategy for the simulation of summer precipitation over the Tibetan Plateau using WRF (v4.0)

Geoscientific Model Development ◽

10.5194/gmd-14-2827-2021 ◽

2021 ◽

Vol 14 (5) ◽

pp. 2827-2841

Author(s):

Ziyu Huang ◽

Lei Zhong ◽

Yaoming Ma ◽

Yunfei Fu

Keyword(s):

Climate Change ◽

Water Vapor ◽

Tibetan Plateau ◽

Regional Climate ◽

Summer Precipitation ◽

Horizontal Wind ◽

The Tibetan Plateau ◽

Model Simulations ◽

Driving Field ◽

Spectral Nudging

Abstract. Precipitation is the key component determining the water budget and climate change of the Tibetan Plateau (TP) under a warming climate. This high-latitude region is regarded as “the Third Pole” of the Earth and the “Asian Water Tower” and influences the eco-economy of downstream regions. However, the intensity and diurnal cycle of precipitation are inadequately depicted by current reanalysis products and regional climate models (RCMs). Spectral nudging is an effective dynamical downscaling method used to improve precipitation simulations of RCMs by preventing simulated fields from drifting away from large-scale reference fields, but the most effective manner of applying spectral nudging over the TP is unclear. In this paper, the effects of spectral nudging parameters (e.g., nudging variables, strengths, and levels) on summer precipitation simulations and associated meteorological variables were evaluated over the TP. The results show that using a conventional continuous integration method with a single initialization is likely to result in the over-forecasting of precipitation events and the over-forecasting of horizontal wind speeds over the TP. In particular, model simulations show clear improvements in their representations of downscaled precipitation intensity and its diurnal variations, atmospheric temperature, and water vapor when spectral nudging is applied towards the horizontal wind and geopotential height rather than towards the potential temperature and water vapor mixing ratio. This altering of the spectral nudging method not only reduces the wet bias of water vapor in the lower troposphere of the ERA-Interim reanalysis (when it is used as the driving field) but also alleviates the cold bias of atmospheric temperatures in the upper troposphere, while maintaining the accuracy of horizontal wind features for the regional model field. The conclusions of this study imply how driving field errors affect model simulations, and these results may improve the reliability of RCM results used to study the long-term regional climate change.

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Plant uptake of CO2 outpaces losses from permafrost and plant respiration on the Tibetan Plateau

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.2015283118 ◽

2021 ◽

Vol 118 (33) ◽

pp. e2015283118

Author(s):

Da Wei ◽

Yahui Qi ◽

Yaoming Ma ◽

Xufeng Wang ◽

Weiqiang Ma ◽

...

Keyword(s):

Tibetan Plateau ◽

Climate Warming ◽

Current Status ◽

The Tibetan Plateau ◽

Low Carbon ◽

Warming Climate ◽

Manipulative Experiments ◽

Warming Rate ◽

Use Efficiency ◽

Plant Respiration

High-latitude and high-altitude regions contain vast stores of permafrost carbon. Climate warming may result in the release of CO2 from both the thawing of permafrost and accelerated autotrophic respiration, but it may also increase the fixation of CO2 by plants, which could relieve or even offset the CO2 losses. The Tibetan Plateau contains the largest area of alpine permafrost on Earth. However, the current status of the net CO2 balance and feedbacks to warming remain unclear, given that the region has recently experienced an atmospheric warming rate of over 0.3 °C decade−1. We examined 32 eddy covariance sites and found an unexpected net CO2 sink during 2002 to 2020 (26 of the sites yielded a net CO2 sink) that was four times the amount previously estimated. The CO2 sink peaked at an altitude of roughly 4,000 m, with the sink at lower and higher altitudes limited by a low carbon use efficiency and a cold, dry climate, respectively. The fixation of CO2 in summer is more dependent on temperature than the loss of CO2 than it is in the winter months, especially at higher altitudes. Consistently, 16 manipulative experiments and 18 model simulations showed that the fixation of CO2 by plants will outpace the loss of CO2 under a wetting–warming climate until the 2090s (178 to 318 Tg C y−1). We therefore suggest that there is a plant-dominated negative feedback to climate warming on the Tibetan Plateau.

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The Evaluation of SMAP Enhanced Soil Moisture Products Using High-Resolution Model Simulations and In-Situ Observations on the Tibetan Plateau

Remote Sensing ◽

10.3390/rs10040535 ◽

2018 ◽

Vol 10 (4) ◽

pp. 535 ◽

Cited By ~ 11

Author(s):

Chengwei Li ◽

Hui Lu ◽

Kun Yang ◽

Menglei Han ◽

Jonathon Wright ◽

...

Keyword(s):

Soil Moisture ◽

High Resolution ◽

Tibetan Plateau ◽

The Tibetan Plateau ◽

Model Simulations ◽

Resolution Model ◽

High Resolution Model ◽

In Situ Observations

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Reconciling the Discrepancy of Post-Volcanic Cooling Estimated from Tree-Ring Reconstructions and Model Simulations over the Tibetan Plateau

Atmosphere ◽

10.3390/atmos10120738 ◽

2019 ◽

Vol 10 (12) ◽

pp. 738

Author(s):

Jianping Duan ◽

Peili Wu ◽

Zhuguo Ma

Keyword(s):

Tibetan Plateau ◽

Climate Variability ◽

Tree Ring ◽

El Niño ◽

El Nino ◽

Southern Oscillation ◽

Volcanic Eruptions ◽

The Tibetan Plateau ◽

Model Simulations ◽

Internal Climate Variability

Volcanic eruptions are a major factor influencing global climate variability, usually with a cooling effect. The magnitudes of post-volcanic cooling from historical eruptions estimated by tree-ring reconstructions differ considerably with the current climate model simulations. It remains controversial on what is behind such a discrepancy. This study investigates the role of internal climate variability (i.e., El Niño/Southern Oscillation (ENSO) warm phase) with a regional focus on the Tibetan Plateau (TP), using tree-ring density records and long historical climate simulations from the fifth Coupled Model Intercomparsion Project (CMIP5). We found that El Niño plays an important role behind the inconsistencies between model simulations and reconstructions. Without associated El Niño events, model simulations agree well with tree-ring records. Divergence appears when large tropical eruptions are followed by an El Niño event. Model simulations, on average, tend to overestimate post-volcanic cooling during those periods as the occurrence of El Niño is random as part of internal climate variability.

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Insights into elevation-dependent warming in the Tibetan Plateau-Himalayas from CMIP5 model simulations

Climate Dynamics ◽

10.1007/s00382-016-3316-z ◽

2016 ◽

Vol 48 (11-12) ◽

pp. 3991-4008 ◽

Cited By ~ 37

Author(s):

Elisa Palazzi ◽

Luca Filippi ◽

Jost von Hardenberg

Keyword(s):

Tibetan Plateau ◽

The Tibetan Plateau ◽

Cmip5 Model ◽

Model Simulations

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