A New Integrated Observational System Over the Tibetan Plateau

Xu, Xiangde; Zhang, Renhe; Shi, Xiaohui; Zhang, Shengjun; Bian, Lingen; Cheng, Xiao; Ding, Guoan; Koike, Takao; Lu, Chungu; Li, Peiyan

doi:10.1175/2008bams2557.1

Cited by 49 publications

(38 citation statements)

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“…Even stronger diurnal patterns in kB 21 have been observed over the Tibetan Plateau. Since 1998, intensive field experiments and comprehensive observational networks have been and are being developed on the Tibetan Plateau (Koike 2004;Ma et al 2008a;Xu et al 2008), which have advanced our understanding on the diurnal kB 21 behavior over this high-altitude alpine area (Ma et al 2002(Ma et al , 2008bYang et al 2003;Y08;Wang and Ma 2011). Even though these studies have resulted in numerous improvements in the parameterization of kB…”

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confidence: 99%

Assessment of Roughness Length Schemes Implemented within the Noah Land Surface Model for High-Altitude Regions

Zheng

Velde

et al. 2014

Journal of Hydrometeorology

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Current land surface models still have difficulties with producing reliable surface heat fluxes and skin temperature (T sfc ) estimates for high-altitude regions, which may be addressed via adequate parameterization of the roughness lengths for momentum (z 0m ) and heat (z 0h ) transfer. In this study, the performance of various z 0h and z 0m schemes developed for the Noah land surface model is assessed for a high-altitude site (3430 m) on the northeastern part of the Tibetan Plateau. Based on the in situ surface heat fluxes and profile measurements of wind and temperature, monthly variations of z 0m and diurnal variations of z 0h are derived through application of the Monin-Obukhov similarity theory. These derived values together with the measured heat fluxes are utilized to assess the performance of those z 0m and z 0h schemes for different seasons. The analyses show that the z 0m dynamics are related to vegetation dynamics and soil water freeze-thaw state, which are reproduced satisfactorily with current z 0m schemes. Further, it is demonstrated that the heat flux simulations are very sensitive to the diurnal variations of z 0h . The newly developed z 0h schemes all capture, at least over the sparse vegetated surfaces during the winter season, the observed diurnal variability much better than the original one. It should, however, be noted that for the dense vegetated surfaces during the spring and monsoon seasons, not all newly developed schemes perform consistently better than the original one. With the most promising schemes, the Noah simulated sensible heat flux, latent heat flux, T sfc , and soil temperature improved for the monsoon season by about 29%, 79%, 75%, and 81%, respectively. In addition, the impact of T sfc calculation and energy balance closure associated with measurement uncertainties on the above findings are discussed, and the selection of the appropriate z 0h scheme for applications is addressed.

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confidence: 99%

Assessment of Roughness Length Schemes Implemented within the Noah Land Surface Model for High-Altitude Regions

Zheng

Velde

et al. 2014

Journal of Hydrometeorology

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“…As a major international cooperation initiative launched by JICA in the area of meteorology, the JICA/Tibet Project started from August 2005 and ended in June 2009. Xu et al (2008a) have reported the construction of the Plateau observing network. Here, after the finish of the project, the present paper introduces the implementation of the project as a whole, and especially the associated achievements.…”

Section: Background and Motivationmentioning

confidence: 99%

A China-Japan Cooperative JICA Atmospheric Observing Network over the Tibetan Plateau (JICA/Tibet Project): An Overviews

Zhang

Koike

et al. 2012

Journal of the Meteorological Society of Japan

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Because of the importance of the impact of the Tibetan Plateau on atmospheric general circulations and climate across China, Asia, and even the world, Chinese and Japanese scientists jointly constructed an integrated atmospheric observing system, especially for the water vapor observation, across the Tibetan Plateau and its adjacent areas during the period of 2005-2009 under the JICA (Japan International Co-operation Agency) project (JICA/Tibet Project). The JICA/Tibet Project aims at understanding processes of the land-atmosphere interaction over the Tibetan Plateau and their impacts on the severe weather and climate over the Tibetan Plateau and the area to its east in the East Asian region. The project is designed in an attempt to alleviate impacts of meteorological disasters in these areas through improving the prediction skill.The implementation of the project has enhanced the capability of monitoring the Plateau atmosphere. The numerical forecast techniques are developed through assimilating observed data into the numerical model. Based on the investigation of observed surface energy balance, the land surface model is improved. It is found that the diurnal variation of precipitation over the Plateau is closely related with water vapor, and the latent heat release is a main factor a¤ecting the Plateau vortex. By analyzing observed seasonal features of the tropopause, the evidence of strong stratosphere and troposphere exchange over the Tibetan Plateau is provided. It reveals that the interannual variability of summer rainfall in East China corresponds to that of vegetation index over the Plateau. The crossing hemispheric circulations driven by the thermal and mechanical forcings of the Plateau play an important role in water vapor transports not only over East Asia, but also in the global scale.

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“…Consequently, a New Integrated Observational System supported by the China-Japan Joint International Co-operation Project over the Tibetan Plateau (NIOST) was implemented in 2005and completed in 2009(CAMS et al 2009). The NIOST observational network provides a mechanism for transferring research results from field experiments into forecast capability, as well as enhancing research activities by providing routinely available long-term datasets (Xu et al 2008b). The observation network covers most of the Tibetan Plateau, a large portion of the Yunnan province (southeast of Tibet; see Fig.…”

Section: Introductionmentioning

confidence: 99%

“…The observation network covers most of the Tibetan Plateau, a large portion of the Yunnan province (southeast of Tibet; see Fig. 1a), and some portions of Sichuan, Guangxi, and other provinces along the Yangtze River Basin (Xu et al 2008b). NIOST comprises several observational platforms, including GPS, GPS sounding (radiosondes with GPS tracking), automated weather stations (AWS), PBL towers, wind profilers, and satellites.…”

Section: Introductionmentioning

confidence: 99%

Use of Integrated Observations to Improve 0-36 h Flood Forecasting: Development and Application of a Coupled Atmosphere-Hydrology System in the Nanpan River Basin, China

Koike

Wang

Liu

et al. 2012

Journal of the Meteorological Society of Japan

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The accuracy of 0-36 h real-time flood forecasting is largely determined by the quantitative precipitation forecasts (QPFs), but convective weather remains a significant challenge for numerical weather prediction systems. Therefore, it is crucial to improve the QPFs' accuracies to predict and prevent flash flood disasters.Corresponding author: Lei Wang: River Lab, Department of Civil Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo-ku, Tokyo 113-8656 Japan. E-mail: wang@hydra.t.u-tokyo.ac.jp 6 2012, Meteorological Society of Japan A coupled atmosphere-hydrology system with the WRF model (together with a three-dimensional variational data assimilation system, 3DVAR) and a distributed biosphere hydrological model (WEB-DHM) is described. This system was then applied to the flood forecasting of the Nanpan River Basin (Yunnan province, China) for 1 July 2008. Based on the available observations (230 surface meteorological sites, 10 conventional Radiosonde sites, and 8 ground-based GPS stations), a series of experiments were conducted with the WRF-3DVAR to investigate the contributions of di¤erent observations to QPF accuracy and flood forecasting. Forced with the observations or the WRF model outputs, WEB-DHM predicts stream-flow at the basin outlet. The overall better performance by the assimilation experiments over the no assimilation case has been clearly demonstrated in the predictions of the 0-36 h heavy rainfall (magnitude and spatial pattern) and flash flood occurrence (peak value and time). The WRF-3DVAR only assimilating GPS data performs poorly, showing the necessity to improve both the assimilation technique and the spatial resolution for the operational numerical weather forecasts. To our knowledge, this work is the first to utilize comprehensive observations around the Tibetan Plateau with a coupled atmosphere-hydrology system to improve short-term flood predictions.

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A New Integrated Observational System Over the Tibetan Plateau

Cited by 49 publications

References 0 publications

Assessment of Roughness Length Schemes Implemented within the Noah Land Surface Model for High-Altitude Regions

Assessment of Roughness Length Schemes Implemented within the Noah Land Surface Model for High-Altitude Regions

A China-Japan Cooperative JICA Atmospheric Observing Network over the Tibetan Plateau (JICA/Tibet Project): An Overviews

Use of Integrated Observations to Improve 0-36 h Flood Forecasting: Development and Application of a Coupled Atmosphere-Hydrology System in the Nanpan River Basin, China

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