Impacts of grassland vegetation cover on the active‐layer thermal regime, northeast Qinghai‐Tibet Plateau, China

Wang, Genxu; Liu, Lin'an; Liu, Guangsheng; Hu, Hongchang; Li, Taibin

doi:10.1002/ppp.699

Cited by 30 publications

(13 citation statements)

References 25 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…However, mean annual NDVI showed that the vegetation had been improved over the observational period (Table S1 in the supporting information). Therefore, the decrease of surface albedo at Chalaping is partly attributed to the changes of vegetation structure, as vegetation modifies the surface energy budget (Wang, Liu, et al, ; X. Wang et al, ). With the improved vegetation greenness, transmitted photosynthetically active radiation increases, and the absorption of shortwave radiation is repartitioned by the canopy components.…”

Section: Discussionmentioning

confidence: 99%

“…Therefore, a number of field experiments were conducted to better understand the hydrothermal processes of the active layer and near‐surface permafrost, and the water‐heat exchanges in seasonal freezing and thawing processes (e.g., Guo et al, ; Luo et al, ; You et al, ; Z. Zhang et al, ; Zhao et al, ). These experimental soil‐vegetation‐atmosphere observations tentatively quantified the hydrothermal dynamics among various terrestrial ecosystems or alternatively provided basic parameters for optimizing land surface process models in various scales (Luo et al, ; Wang et al, ; Wang, Bai, et al, ; Wang, Liu, et al, ; Yi et al, ; Zhao et al, ). Nevertheless, these experiments had been mostly conducted in the intensive observation periods or focused on the variations of hydrothermal processes based only on soil moisture content and temperatures.…”

Section: Introductionmentioning

confidence: 99%

“…The variation of surface radiation budgets likely contributes to the rising of LST, as confirmed by the remote sensing‐based Moderate Resolution Imaging Spectroradiometer (MODIS) daytime and nighttime temperatures (Cai et al, ). Consequently, the alpine ecosystems (e.g., alpine meadows and alpine swamp meadows) degraded significantly under the synergic effects of climate warming and permafrost degradation (Wang, Liu, et al, ; Xue et al, ). To account for the changes of alpine ecosystems in permafrost regions, there is an urgent need to characterize the water‐heat exchanges between the land surface and the atmosphere, particularly the variation of soil heat flux.…”

Section: Introductionmentioning

confidence: 99%

“…Zhang et al, 2017;Zhao et al, 2000). These experimental soil-vegetation-atmosphere observations tentatively quantified the hydrothermal dynamics among various terrestrial ecosystems or alternatively provided basic parameters for optimizing land surface process models in various scales (Luo et al, 2014;Wang et al, 2012;Wang, Bai, et al, 2010;Wang, Liu, et al, 2010;Yi et al, 2014;Zhao et al, 2000). Nevertheless, these experiments had been mostly conducted in the intensive observation periods or focused on the variations of hydrothermal processes based only on soil moisture content and temperatures.…”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Characteristics of Water‐Heat Exchanges and Inconsistent Surface Temperature Changes at an Elevational Permafrost Site on the Qinghai‐Tibet Plateau

Luo

Jin

et al. 2018

JGR Atmospheres

View full text Add to dashboard Cite

Increase of surface temperatures has long been recognized as an unequivocal response to radiative forcing and one of the most important implications for global warming. However, it remains unclear whether the variation of ground surface temperature (GST) and soil temperatures is consistent with simultaneous changes of the near‐surface air and land (or skin) surface temperatures (Ta and LST). In this study, a seven‐year continuous observation of GST, Ta, and surface water and heat exchange was carried out at an elevational permafrost site at Chalaping, northeastern Qinghai‐Tibet Plateau. Results showed a distinct retarding of warming on the ground surface and subsurface under the presence of dense vegetation and moist peat substrates. Mean annual Ta and LST increased at noteworthy rates of 0.22 and 0.32 °C/a, respectively, while mean annual GST increased only at a rate of 0.057 °C/a. No obvious trends were detected for the four radiation budgets except the soil heat flux (G), which significantly increased at a rate of 0.29 W · m−2 · a−1, presumably inducing the melting of ground ice and resulted in much higher moisture content through the summers of 2015 and 2016 than preceding years and subsequent 2017 at the depths between 80 and 120 cm. However, no noticeable immediate variations of soil temperatures occurred owing to the large latent heat effect (thermal inertia) and the extending zero‐curtain period. We suggest that a better protected eco‐environment, particularly the surface vegetation, helps preserving the underlying permafrost, and thus to mitigates the potential degradation of elevational permafrost on the Qinghai‐Tibet Plateau.

show abstract

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Characteristics of Water‐Heat Exchanges and Inconsistent Surface Temperature Changes at an Elevational Permafrost Site on the Qinghai‐Tibet Plateau

Luo

Jin

et al. 2018

JGR Atmospheres

View full text Add to dashboard Cite

show abstract

“…Both experimental studies [ Blok et al ., ] and modeling studies [ Yi et al ., ] have demonstrated that increases in vegetation cover would delay thawing of permafrost in the arctic region. Field studies also suggested that changes in alpine grassland cover affect soil thermal dynamics on the Qinghai‐Tibetan Plateau [ Wang et al ., ]. These effects have seldom been considered in modeling studies on the Qinghai‐Tibetan Plateau within ecosystem models [ Zhang et al ., ; Zhuang et al ., ].…”

Section: Introductionmentioning

confidence: 99%

Representing the effects of alpine grassland vegetation cover on the simulation of soil thermal dynamics by ecosystem models applied to the Qinghai‐Tibetan Plateau

Xiang³

et al. 2013

JGR Biogeosciences

View full text Add to dashboard Cite

[1] Soil surface temperature is a critical boundary condition for the simulation of soil temperature by environmental models. It is influenced by atmospheric and soil conditions and by vegetation cover. In sophisticated land surface models, it is simulated iteratively by solving surface energy budget equations. In ecosystem, permafrost, and hydrology models, the consideration of soil surface temperature is generally simple. In this study, we developed a methodology for representing the effects of vegetation cover and atmospheric factors on the estimation of soil surface temperature for alpine grassland ecosystems on the QinghaiTibetan Plateau. Our approach integrated measurements from meteorological stations with simulations from a sophisticated land surface model to develop an equation set for estimating soil surface temperature. After implementing this equation set into an ecosystem model and evaluating the performance of the ecosystem model in simulating soil temperature at different depths in the soil profile, we applied the model to simulate interactions among vegetation cover, freeze-thaw cycles, and soil erosion to demonstrate potential applications made possible through the implementation of the methodology developed in this study. Results showed that (1) to properly estimate daily soil surface temperature, algorithms should use air temperature, downward solar radiation, and vegetation cover as independent variables; (2) the equation set developed in this study performed better than soil surface temperature algorithms used in other models; and (3) the ecosystem model performed well in simulating soil temperature throughout the soil profile using the equation set developed in this study. Our application of the model indicates that the representation in ecosystem models of the effects of vegetation cover on the simulation of soil thermal dynamics has the potential to substantially improve our understanding of the vulnerability of alpine grassland ecosystems to changes in climate and grazing regimes.Citation: Yi, S., N. Li, B. Xiang, X. Wang, B. Ye, and A. D. McGuire (2013), Representing the effects of alpine grassland vegetation cover on the simulation of soil thermal dynamics by ecosystem models applied to the Qinghai-Tibetan Plateau,

show abstract

Impacts of Summer Extreme Precipitation Events on the Hydrothermal Dynamics of the Active Layer in the Tanggula Permafrost Region on the Qinghai‐Tibetan Plateau

Zhu

Ren

et al. 2017

JGR Atmospheres

View full text Add to dashboard Cite

The characteristics of long‐term variation for extreme precipitation events were analyzed at the Tanggula site in the continuous permafrost regions of the Qinghai‐Tibetan Plateau (QTP). In addition, the impacts of extreme precipitation events in summer on soil thermal‐moisture dynamics were also investigated. The results showed that local extreme precipitation indices fluctuated significantly and that the trend magnitudes of local very wet days (R95p), annual total wet‐day precipitation (PRCPTOT), number of heavy precipitation days (R10mm), maximum length of dry spell (CDD), and simple daily intensity index (SDII) were larger than those of the western QTP, other regions of China, and even the global average. The freeze‐thaw cycling in the local active layer occurred from October to the next September during 2006 to 2014. The influence of extreme precipitation event in summer on local soil hydrothermal conditions could reach soil depths up to 105 cm or so, and these were more pronounced than with light or moderate precipitation events. Soil temperature reacted more promptly to local extreme precipitation events than did soil moisture. The rate at which local soil temperature fell after an extreme precipitation event was greater than the rate of increasing temperature on nonprecipitation days. Moreover, the amount of precipitation received during extreme precipitation events had a greater effect on local soil moisture and temperature than duration time for these events. Consecutive extreme precipitation events with a longer duration time did not necessarily to have a greater effect than a single precipitation event with a shorter duration. Finally, the thawing process of active layer and local water migration modes could also affect the response of soil hydrothermal conditions to an extreme precipitation event to a large extent.

show abstract

Impacts of grassland vegetation cover on the active‐layer thermal regime, northeast Qinghai‐Tibet Plateau, China

Cited by 30 publications

References 25 publications

Characteristics of Water‐Heat Exchanges and Inconsistent Surface Temperature Changes at an Elevational Permafrost Site on the Qinghai‐Tibet Plateau

Characteristics of Water‐Heat Exchanges and Inconsistent Surface Temperature Changes at an Elevational Permafrost Site on the Qinghai‐Tibet Plateau

Representing the effects of alpine grassland vegetation cover on the simulation of soil thermal dynamics by ecosystem models applied to the Qinghai‐Tibetan Plateau

Impacts of Summer Extreme Precipitation Events on the Hydrothermal Dynamics of the Active Layer in the Tanggula Permafrost Region on the Qinghai‐Tibetan Plateau

Contact Info

Product

Resources

About