Representing permafrost properties in CoLM for the Qinghai–Xizang (Tibetan) Plateau

Xiao, Yao; Zhao, Lin; Dai, Yongjiu; Li, Ren; Pang, Qiangqiang; Yao, Jimin

doi:10.1016/j.coldregions.2012.12.004

Cited by 57 publications

(38 citation statements)

References 49 publications

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“…Although the CLM3.5 land surface model performs well in some respects, there are uncertainties in estimates of soil temperature and water content and the surface energy budget on the TP [ Xia et al ., ; Chen et al ., , ]. Other studies have applied the original model (Common Land Model, CoLM) to simulations of the land surface processes over the TP and have come to similar conclusions [ Luo et al ., ; Yang et al ., ; Xiao et al ., ].…”

Section: Introductionmentioning

confidence: 99%

Effects of modified soil water‐heat physics on RegCM4 simulations of climate over the Tibetan Plateau

et al. 2016

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To optimize the description of land surface processes and improve climate simulations over the Tibetan Plateau (TP), a modified soil water‐heat parameterization scheme (SWHPS) is implemented into the Community Land Model 3.5 (CLM3.5), which is coupled to the regional climate model 4 (RegCM4). This scheme includes Johansen's soil thermal conductivity scheme together with Niu's groundwater module. Two groups of climate simulations are then performed using the original RegCM4 and revised RegCM4 to analyze the effects of the revised SWHPS on regional climate simulations. The effect of the revised RegCM4 on simulated air temperature is relatively small (with mean biases changing by less than 0.1°C over the TP). There are overall improvements in the simulation of winter and summer air temperature but increased errors in the eastern TP. It has a significant effect on simulated precipitation. There is also a clear improvement in simulated annual and winter precipitation, particularly over the northern TP, including the Qilian Mountains and the source region of the Yellow River. There are, however, increased errors in precipitation simulation in parts of the southern TP. The precipitation difference between the two models is caused mainly by their convective precipitation difference, particularly in summer. Overall, the implementation of the new SWHPS into the RegCM4 has a significant effect not only on land surface variables but also on the overlying atmosphere through various physical interactions.

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Section: Introductionmentioning

confidence: 99%

Effects of modified soil water‐heat physics on RegCM4 simulations of climate over the Tibetan Plateau

et al. 2016

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“…QMB soil temperature measurement was a standardized routine at most meteorological stations in China before 2010, in which thermometers are placed in small holes at various depths and the measurements are made by pulling out and reading the thermometers at fixed times every day. CEERI soil temperature was measured by the 105 T sensors with an accuracy of 0.1°C [Xiao et al, 2013].…”

Section: Station Locations and Observationsmentioning

confidence: 99%

Frozen soil degradation and its effects on surface hydrology in the northern Tibetan Plateau

et al. 2015

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Frozen soil was simulated at six seasonally frozen and seven permafrost stations over the northern Tibetan Plateau using the Variable Infiltration Capacity (VIC) model for the period of 1962-2009. The VIC model resolved the seasonal cycle and temporal evolution of the observed soil temperatures and liquid soil moisture well. The simulated long-term changes during 1962-2009 indicated mostly positive trends for both soil temperature and soil moisture, and negative trends for soil ice content at annual and monthly time scales, although differences existed among the stations, soil layers, and seasons. Increases in soil temperature were due mainly to increases in daily air temperature maxima and internal soil heat conduction, while decreases in soil ice content were related to the warming of frozen soil. For liquid soil moisture, increases in the cold months can be attributed to increases in soil temperature and enhanced soil ice melt while changes in the warm months were the results of competition between positive precipitation and negative soil temperature effects. Precipitation and liquid soil moisture were strongly correlated with evapotranspiration and runoff but had various degrees of correlations with base flow during May-September. Seasonally frozen stations displayed longer and more active hydrological processes than permafrost stations. Slight enhancement of the surface hydrological processes at the study stations was indicated, due to the combined effects of precipitation changes, which were dominant, and frozen soil degradation.

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“…The instrumentation includes a 10 m high automatic weather station, an active‐layer monitoring system that measures soil moisture and temperature in the active layer at 5, 10, 20, 40, 70, 105, 140, 175, 210, 245 and 280 cm depth, and a borehole system that measures soil temperature at 1300 and 1500 cm depth. Active‐layer thickness (ALT) and MAGT at 15 m depth were 3.58 m and −1.21°C in 2010, respectively …”

Section: Materials and Methodologymentioning

confidence: 99%

Spatial modeling of permafrost distribution and properties on the Qinghai‐Tibet Plateau

Zhang

Zhao

et al. 2018

Permafrost & Periglacial

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Accurate information on the distribution of permafrost and its thermal and hydrological properties is critical for environmental management and engineering development. This study modeled the current state of permafrost on the Qinghai‐Tibet Plateau (QTP), including the spatial distribution of permafrost, active‐layer thickness (ALT), mean annual ground temperature (MAGT), depth of zero annual amplitude (DZAA) and ground‐ice content using an improved Noah land surface model (LSM). The improved model was examined at a typical permafrost site and then applied to the entire QTP using existing gridded meteorological data and newly developed soil data. The simulated permafrost distribution and properties were validated against existing permafrost maps in three representative survey areas and with measurements from 54 boreholes. The results indicate that the Noah LSM with augmented physics and proper soil data support can model permafrost over the QTP. Permafrost was simulated to underlie an area of 1.113 × 106 km2 in 2010, accounting for 43.8% of the entire area of the QTP. The modeled regional average ALT and MAGT were 3.23 m and −1.56°C, respectively. Spatially, MAGT increases and DZAA becomes shallower from north to south. Thermally unstable permafrost (MAGT above −0.5°C) is predominant, accounting for 38.75% of the whole permafrost area on the QTP. Ice‐rich permafrost was mainly simulated around lakes across the north‐central QTP.

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Representing permafrost properties in CoLM for the Qinghai–Xizang (Tibetan) Plateau

Cited by 57 publications

References 49 publications

Effects of modified soil water‐heat physics on RegCM4 simulations of climate over the Tibetan Plateau

Effects of modified soil water‐heat physics on RegCM4 simulations of climate over the Tibetan Plateau

Frozen soil degradation and its effects on surface hydrology in the northern Tibetan Plateau

Spatial modeling of permafrost distribution and properties on the Qinghai‐Tibet Plateau

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