Formation and variation of the atmospheric heat source over the Tibetan Plateau and its climate effects

Wu, Guoxiong; He, Bian; Duan, Anmin; Liu, Yimin; Yu, Wei

doi:10.1007/s00376-017-7014-5

Cited by 61 publications

(36 citation statements)

References 36 publications

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“…Over the TP, soil moisture is a crucial state variable for land-atmosphere interactions. It controls the partition of net radiation into sensible and latent heat, both of which are closely related to TP thermal forcing and have been demonstrated to exert significant impacts on the Asian monsoon and general circulation (e.g., Ye and Wu, 1998;Liu et al, 2012;Wu et al, 2017). As surface soil moisture (SSM; soil moisture in the top 10 cm of the soil layer) plays a key role in modulating the surface energy and water partition, we primarily focus on SSM modeling here.…”

Section: Introductionmentioning

confidence: 99%

Evaluations of Uncertainty and Sensitivity in Soil Moisture Modeling on the Tibetan Plateau

Peng

Sun

2020

Tellus A: Dynamic Meteorology and Oceanography

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To provide scientific support for improvements in land surface modeling on the Tibetan Plateau (TP) by reducing uncertainties in the physical parameters of models, comprehensive uncertainty and sensitivity evaluations were performed for the simulation of surface soil moisture (SSM). Five observational stations were selected for the study. The conditional nonlinear optimal perturbation related to parameters (CNOP-P) approach and the Common Land Model (CoLM) with 28 uncertain parameters were employed to evaluate the maximal uncertainty of the simulated SSM. The uncertainty analysis indicated that the parameter errors could induce large uncertainties. These uncertainties in the SSM generally fluctuated over the range from 0.33 to 0.64 m 3 m À3 in terms of absolute changes and from 235% to 510% in terms of percentage changes. The uncertainty analysis addressed the necessity of decreasing the uncertainties in the parameters. When resources are limited, the most important and sensitive parameter set should first be identified in order to reduce uncertainties. To find this parameter set, a sensitivity analysis framework based on the CNOP-P approach was applied. The results showed that the most sensitive and important combinations of 4 parameters changed slightly among the study sites and consisted of soil texture-related parameters. Although the most sensitive and important parameter combinations only had 4 elements, the uncertainties that they could induce accounted for a large proportion of the uncertainties caused by all 28 uncertain parameters. Furthermore, the decreases in parameter errors, which were derived from the CNOP-Ps of the most sensitive and important parameter combinations, led to the maximal reductions in the uncertainties of the simulated SSM. The above results imply that we should prioritize reducing the uncertainty of sensitive parameters or parameter combinations in order to improve prediction and simulation abilities.

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Section: Introductionmentioning

confidence: 99%

Evaluations of Uncertainty and Sensitivity in Soil Moisture Modeling on the Tibetan Plateau

Peng

Sun

2020

Tellus A: Dynamic Meteorology and Oceanography

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“…The TP is a huge heat source in warm seasons and results in vigorous convective clouds systems (e.g., Ge et al, 2019; Luo & Yanai, 1984; Wu et al, 2017). Convective clouds, especially the deep convections (DCs), can lead to heavy rainfall events and play an important role in the local energy and water cycle.…”

Section: Introductionmentioning

confidence: 99%

Large‐Scale Circulation Environment and Microphysical Characteristics of the Cloud Systems Over the Tibetan Plateau in Boreal Summer

Chen

Yin

et al. 2020

Earth and Space Science

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The Tibetan Plateau (TP) experiences a particular dynamical and thermal environment due to its unique topography, which could affect the generation and development of its cloud and precipitation. Statistical results of 52-year daily precipitation (1961 to 2012) show that the most frequent daily precipitation is about 3 mm day −1 over the eastern TP (ETP) in the warm season while it is less than 1 mm day −1 over the western TP (WTP). Circulation patterns for rainy and rainless conditions over both the ETP and WTP are investigated. The results show that the rainy weather over the TP is usually related to the moisture transported from the warm ocean by the southerly flow. Moreover, rainy weather in WTP can only appear when the strong southerly flow prevails over the Indian subcontinent. When the south flow is weak, the rainy weather can still develop in ETP under favorable conditions due to the local madid environment. CloudSat observations show that the strong convective system can extend to a level as high as 16 km above the sea level with a favorable dynamical and thermal environment. However, the depth of most precipitating convective clouds over the TP is in a range of 6-9 km. Due to the wetter condition, the precipitating convective cloud holds a lower cloud base in August in ETP than WTP. Compared with other regions, the precipitating convective clouds in both the ETP and WTP are thinner in cloud depth, smaller in cloud particles and weaker in precipitation capacity.

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“…Compared with other regions at similar Northern Hemisphere latitudes, TP acts as a huge heat source to the atmosphere (Yang et al, ), largely via sensible heat fluxes (SH). It thus plays a crucial role in the seasonal conversion, onset, and maintenance of the Asian monsoon and determining the spatiotemporal patterns of the associated precipitation over the Indo‐China region in spring and summer (Duan et al, ; Duan & Wu, ; C. F. Li & Yanai, ; Wu et al, ; Xu et al, ; Ye & Wu, ). Synchronous SH anomalies in Central Asia and TP were also shown in numerical experiments to have caused diabatic heating and circulation anomalies that resulted in extremely heavy snow over South China in January 2008 (L. F. Li et al, ).…”

Section: Introductionmentioning

confidence: 99%

Distribution and Variation of the Surface Sensible Heat Flux Over the Central and Eastern Tibetan Plateau: Comparison of Station Observations and Multireanalysis Products

et al. 2019

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Surface sensible heat fluxes (SH) over Tibetan Plateau (TP) dictate the seasonal conversion, onset and maintenance of the Asian monsoon. Spatiotemproal variability in SH over central and eastern TP (CETP) from reanalysis products (i.e., JRA55, ERA‐Interim, NCEP1, and NCEP2) and derived using bulk transfer approximations applied to observations is characterized for all seasons during 1980–2015 and is diagnosed in the context of two important drivers of variability: wind speed and land‐air temperature difference (Tg‐Ta). In the climatological mean, SH from observations increases from east to west and exhibits obvious seasonality with highest value in spring and lowest in winter. Declines in SH prior to 2000 as manifest in the observations appears to have resulted from changes in wind speeds, and the subsequent recovery is attributable to increases in both wind speeds and air‐surface temperature gradients. The intercomparison shows that ERA‐Interim exhibits greatest accord with observations in terms of the climatological distribution and seasonality, and all reanalyses exhibit some aspects of the temporal variability and long‐term trends as manifest in the observations. However, the root causes of the long‐term variability in SH as manifest in the reanalysis products are not consistent with inferences derived from the observations.

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Formation and variation of the atmospheric heat source over the Tibetan Plateau and its climate effects

Cited by 61 publications

References 36 publications

Evaluations of Uncertainty and Sensitivity in Soil Moisture Modeling on the Tibetan Plateau

Evaluations of Uncertainty and Sensitivity in Soil Moisture Modeling on the Tibetan Plateau

Large‐Scale Circulation Environment and Microphysical Characteristics of the Cloud Systems Over the Tibetan Plateau in Boreal Summer

Distribution and Variation of the Surface Sensible Heat Flux Over the Central and Eastern Tibetan Plateau: Comparison of Station Observations and Multireanalysis Products

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