Sensitivity of regional climate simulations to land-surface schemes on the Tibetan Plateau

2014 ◽  
Vol 62 (1) ◽  
pp. 25-43 ◽  
Author(s):  
X Wang ◽  
M Yang ◽  
G Pang
Keyword(s):  
Tibetan Plateau ◽  
Land Surface ◽  
Regional Climate ◽  
The Tibetan Plateau ◽  
Climate Simulations

scholarly journals Uncertainty and Variation of Remotely Sensed Lake Ice Phenology across the Tibetan Plateau

2018 ◽  
Vol 10 (10) ◽  
pp. 1534 ◽  
Author(s):  
Linan Guo ◽  
Yanhong Wu ◽  
Hongxing Zheng ◽  
Bing Zhang ◽  
Junsheng Li ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Land Surface ◽  
Regional Climate ◽  
Local Environment ◽  
Remotely Sensed ◽  
The Tibetan Plateau ◽  
Remotely Sensed Data ◽  
Lake Ice ◽  
Reflectance Data ◽  
Ice Phenology

In the Tibetan Plateau (TP), the changes of lake ice phenology not only reflect regional climate change, but also impose substantial ecohydrological impacts on the local environment. Due to the limitation of ground observation, remote sensing has been used as an alternative tool to investigate recent changes of lake ice phenology. However, uncertainties exist in the remotely sensed lake ice phenology owing to both the data and methods used. In this paper, three different remotely sensed datasets are used to investigate the lake ice phenology variation in the past decade across the Tibetan Plateau, with the consideration of the underlying uncertainties. The remotely sensed data used include reflectance data, snow product, and land surface temperature (LST) data of moderate resolution imaging spectroradiometer (MODIS). The uncertainties of the three methods based on the corresponding data are assessed using the triple collocation approach. Comparatively, it is found that the method based on reflectance data outperforms the other two methods. The three methods are more consistent in determining the thawing dates rather than the freezing dates of lake ice. It is consistently shown by the three methods that the ice-covering duration in the northern part of the TP lasts longer than that in the south. Though there is no general trend of lake ice phenology across the TP for the period of 2000–2015, the warmer climate and stronger wind have led to the earlier break-up of lake ice.

Detecting evapotranspiration biases in reanalyses and regional climate modeling

2021 ◽  
Author(s):  
Jingyu Dan ◽  
Yanhong Gao
Keyword(s):  
Tibetan Plateau ◽  
Land Surface ◽  
Water Cycle ◽  
Climate Modeling ◽  
Global Climate ◽  
Monsoon Season ◽  
Regional Climate ◽  
Horizontal Resolution ◽  
The Tibetan Plateau ◽  
Free Atmosphere

<p>As the highest plateau in the world, the Tibetan Plateau (TP) exerts great impacts on regional and global climate and water cycle through interactions between land and free atmosphere. Terrestrial evapotranspiration is a critical component of the Earth's water cycle. To better understand the heterogeneity of the evapotranspiration over the Tibetan Plateau and its influences, we conducted a whole year dynamical downscale modelling (DDM) with the horizontal resolution at 28km and a convection permitting modelling (CPM) at 4km for 2014. DDM and CPM simulation results are compared with an satellite retrieving dataset, which is referred as OBS in the following, the global land surface data assimilation system (GLDAS) and two commonly used reanalyses ERA-Interim and ERA5, as well. The annual and seasonal means and seasonal variabilities are inter-compared. The evapotranspiration over ten dominant land use types are investigated based on six datasets. Differences with the satellite dataset are illustrated and relationships with soil moisture and temperature, precipitation and radiation are explored. The followings are obtained. GLDAS generally reproduces magnitude and pattern of the OBS; reanalyses overestimate, DDM and CPM underestimate compared to the OBS and GLDAS.</p><p>The overestimations in reanalyses occur in the monsoon season and the underestimations in DDM and CPM occur in the non-monsoon season. Large evapotranspiration biases exist over the vegetated ground which exert large impacts on the TP-average biases for growing season.</p>

scholarly journals Vegetation Expansion on the Tibetan Plateau and Its Relationship with Climate Change

2020 ◽  
Vol 12 (24) ◽  
pp. 4150
Author(s):  
Zhipeng Wang ◽  
Jianshuang Wu ◽  
Ben Niu ◽  
Yongtao He ◽  
Jiaxing Zu ◽  
...  
Keyword(s):  
Tibetan Plateau ◽  
Land Cover ◽  
Land Surface ◽  
Large Scale ◽  
Regional Climate ◽  
Expansion Rate ◽  
The Tibetan Plateau ◽  
Vegetation Monitoring ◽  
Climate Conditions ◽  
Vegetation Expansion

The natural shift in land cover from non-vegetated to vegetated land is termed as vegetation expansion, which has substantial impacts on regional climate conditions and land surface energy balance. Barrens dominate the northwestern Tibetan Plateau, where vegetation is predicted to expand northwestward with the ongoing climate warming. However, rare studies have confirmed such a forecast with large-scale vegetation monitoring. In this study, we used a landcover dataset, classified according to the International Geosphere–Biosphere Program criteria, to examine previous model-based predictions and the role of climate on the expansion rate across the plateau. Our results showed that shrublands, open forests, grasslands, and water bodies expanded while evergreen and deciduous broadleaf forests, croplands and barrens shrank during the period 2001–2018. Vegetation expanded by 33,566 km2 accounting for about 1.3% of the total area of this plateau and the land cover shifting from barrens to grasslands was the primary way of vegetation expansion. Spatially, the vegetation expanded northwestward to lands with colder, drier, and more radiation in the climate. Increasing precipitation positively correlated with the vegetation expansion rate for the arid and semi-arid northwest Tibetan Plateau and warming contributed to the vegetation expanding in the semi-humid southeast Tibetan Plateau. Our results verified the predictions of models and highlighted the “greening” on barrens in recent years.

Trends of land surface heat fluxes on the Tibetan Plateau from 2001 to 2012

2017 ◽  
Vol 37 (14) ◽  
pp. 4757-4767 ◽  
Author(s):  
Cunbo Han ◽  
Yaoming Ma ◽  
Xuelong Chen ◽  
Zhongbo Su
Keyword(s):  
Tibetan Plateau ◽  
Land Surface ◽  
Surface Heat ◽  
Heat Fluxes ◽  
The Tibetan Plateau ◽  
Surface Heat Fluxes ◽  
Land Surface Heat Fluxes

Simulations of the Impact of Lakes on Local and Regional Climate Over the Tibetan Plateau

2017 ◽  
Vol 56 (4) ◽  
pp. 230-239 ◽  
Author(s):  
Lingjing Zhu ◽  
Jiming Jin ◽  
Xin Liu ◽  
Lei Tian ◽  
Qunhui Zhang
Keyword(s):  
Tibetan Plateau ◽  
Regional Climate ◽  
The Tibetan Plateau ◽  
The Impact

Paleolake salinity evolution in the Qaidam Basin (NE Tibetan Plateau) between ~42 and 29 Ma: Links to global cooling and Paratethys sea incursions

2021 ◽  
Author(s):  
Chengcheng Ye ◽  
Yibo Yang ◽  
Xiaomin Fang ◽  
Weilin Zhang ◽  
Chunhui Song ◽  
...  
Keyword(s):  
Climate Change ◽  
Tibetan Plateau ◽  
Middle Eocene ◽  
Qaidam Basin ◽  
Regional Climate ◽  
Regional Climate Change ◽  
Driving Mechanism ◽  
The Tibetan Plateau ◽  
Early Oligocene ◽  
Global Cooling

<p>Global cooling, the early uplift of the Tibetan Plateau, and the retreat of the Paratethys are three main factors that regulate long-term climate change in the Asian interior during the Cenozoic. However, the debated elevation history of the Tibetan Plateau and the overlapping climate effects of the Tibetan Plateau uplift and Paratethys retreat makes it difficult to assess the driving mechanism on regional climate change in a particular period. Some recent progress suggests that precisely dated Paratethys transgression/regression cycles appear to have fluctuated over broad regions with low relief in the northern Tibetan Plateau in the middle Eocene–early Oligocene, when the global climate was characterized by generally continuous cooling followed by the rapid Eocene–Oligocene climate transition (EOT). Therefore, a middle Eocene–early Oligocene record from the Asian interior with unambiguous paleoclimatic implications offers an opportunity to distinguish between the climatic effects of the Paratethys retreat and those of global cooling.</p><p>Here, we present a complete paleolake salinity record from middle Eocene to early Miocene (~42-29 Ma) in the Qaidam Basin using detailed clay boron content and clay mineralogical investigations. Two independent paleosalimeters, equivalent boron and Couch’s salinity, collectively present a three-staged salinity evolution, from an oligohaline–mesohaline environment in the middle Eocene (42-~34 Ma) to a mesosaline environment in late Eocene-early Oligocene (~34-~29 Ma). This clay boron-derived salinity evolution is further supported by the published chloride-based and ostracod-based paleosalinity estimates in the Qaidam Basin. Our quantitative paleolake reconstruction between ~42 and 29 Ma in the Qaidam Basin resembles the hydroclimate change in the neighboring Xining Basin, of which both present good agreement with changes of marine benthic oxygen isotope compositions. We thus speculated that the secular trend of clay boron-derived paleolake salinity in ~42-29 Ma is primarily controlled by global cooling, which regulates regional climate change by influencing the evaporation capacity in the moisture source of Qaidam Basin. Superimposed on this trend, the Paratethys transgression/regression cycles served as an important factor regulating wet/dry fluctuations in the Asian interior between ~42 and ~34 Ma.</p>

scholarly journals Statistics of optical and geometrical properties of cirrus cloud over tibetan plateau measured by lidar and radiosonde

2018 ◽  
Vol 176 ◽  
pp. 05040
Author(s):  
Guangyao Dai ◽  
Songhua Wu ◽  
Xiaoquan Song ◽  
Xiaochun Zhai
Keyword(s):  
Tibetan Plateau ◽  
Hydrological Cycle ◽  
Regional Climate ◽  
Cirrus Clouds ◽  
Dynamic Processes ◽  
Cirrus Cloud ◽  
The Tibetan Plateau ◽  
Temperature Deviation ◽  
Geometrical Properties ◽  
Temperature Dependences

Cirrus clouds affect the energy budget and hydrological cycle of the earth’s atmosphere. The Tibetan Plateau (TP) plays a significant role in the global and regional climate. Optical and geometrical properties of cirrus clouds in the TP were measured in July-August 2014 by lidar and radiosonde. The statistics and temperature dependences of the corresponding properties are analyzed. The cirrus cloud formations are discussed with respect to temperature deviation and dynamic processes.

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