Chongqing Meteorological Administration

Chongqing, China

Chongqing Meteorological Administration

Chongqing, China
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Wang G.,Chinese Academy of Meteorological Sciences | Liu L.,Chinese Academy of Meteorological Sciences | Liu Z.,Ocean University of China | Lu B.,Shandong Meteorological Administration | Mu R.,Chongqing Meteorological Administration
Advances in Atmospheric Sciences | Year: 2011

The mobile incoherent Doppler lidar (MIDL), which was jointly developed by State Key Laboratory of Severe Weather (LaSW) of the Chinese Academy of Meteorological Sciences (CAMS) and Ocean University of China, provided meteorological services during the Olympic sailing events in Qingdao in 2008. In this study, two experiments were performed based on these measurements. First, the capabilities of MIDL detection of sea-surface winds were investigated by comparing its radial velocities with those from a sea buoy. MIDL radial velocity was almost consistent with sea-buoy data; both reflected the changes in wind with time. However, the MIDL data was 0. 5 m s-1 lower on average than the sea-buoy data due to differences in detection principle, sample volume, sample interval, spatial and temporal resolution. Second, the wind fields during the Olympic sailing events were calculated using a four-dimensional variation data assimilation (4DVAR) algorithm and were evaluated by comparing them with data from a sea buoy. The results show that the calculations made with the 4DVAR wind retrieval method are able to simulate the fine retrieval of sea-surface wind data-the retrieved wind fields were consistent with those of sea-buoy data. Overall, the correlation coefficient of wind direction was 0. 93, and the correlation coefficient of wind speed was 0. 70. The distribution of retrieval wind fields was consistent with that of MIDL radial velocity; the root-mean-square error between them had an average of only 1. 52 m s-1. © 2011 Chinese National Committee for International Association of Meteorology and Atmospheric Sciences, Institute of Atmospheric Physics, Science Press and Springer-Verlag Berlin Heidelberg.


Zeng G.,Nanjing University of Information Science and Technology | Zeng G.,CAS Institute of Atmospheric Physics | Yu Y.,Nanjing University of Information Science and Technology | Zhou G.,Chongqing Meteorological Administration | Li C.,Guangzhou Institute of Tropical and Marine Meteorology
Proceedings - 2010 International Conference on Digital Manufacturing and Automation, ICDMA 2010 | Year: 2010

This study investigates the roles of tropical Indian-Pacific oceans SSTs in the interdecadal variability of East Asian Summer Monsoon (EASM) during the second half of the twentieth century based on simulations from an atmospheric general circulation model, NCAR CAM3 (Community Atmospheric Model). These simulations are conducted by the observed 1950-2000 monthly SSTs in the tropical Indian-Pacific oceans, tropical Indian Ocean and tropical Pacific, independently. Results show that CAM3 is able to simulate the observed interdecadal weakening of EASM occurred in the mid-late 1970s when SSTs in tropical Indian-Pacific Oceans and tropical Pacific SSTs are determined, but to simulate the interdecadal strengthening of EASM when SSTs in the tropical Indian Ocean are determined. These results indicate that SST anomaly in the tropical Pacific plays a central role in the interdecadal weakening of EASM occurred in the mid-late of 1970s, while SST anomaly in the tropical Indian Ocean plays a converse role in it. As a background, the interdecadal variation of tropical Pacific SSTs has an important effect upon the interdecadal weakening of EASM. © 2010 IEEE.


Yi S.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Li N.,Beijing Special Meteorological Observatory | Xiang B.,Chongqing Meteorological Administration | Wang X.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | And 2 more authors.
Journal of Geophysical Research: Biogeosciences | Year: 2013

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 Qinghai-Tibetan 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. © 2013. American Geophysical Union. All Rights Reserved.


Yi S.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Wang X.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | Wang X.,University of Chinese Academy of Sciences | Qin Y.,CAS Lanzhou Cold and Arid Regions Environmental and Engineering Research Institute | And 2 more authors.
Environmental Research Letters | Year: 2014

Permafrost plays a critical role in soil hydrology. Thus, the degradation of permafrost under warming climate conditions may affect the alpine grassland ecosystem on the Qinghai-Tibetan Plateau. Previous space-for-time studies using plot and basin scales have reached contradictory conclusions. In this study, we applied a process-based ecosystem model (DOS-TEM) with a state-of-the-art permafrost hydrology scheme to examine this issue. Our results showed that 1) the DOS-TEM model could properly simulate the responses of soil thermal and hydrological dynamics and of ecosystem dynamics to climate warming and spatial differences in precipitation; 2) the simulated results were consistent with plot-scale studies showing that warming caused an increase in maximum unfrozen thickness, a reduction in vegetation and soil carbon pools as a whole, and decreases in soil water content, net primary production, and heterotrophic respiration; and 3) the simulated results were also consistent with basin-scale studies showing that the ecosystem responses to warming were different in regions with different combinations of water and energy constraints. Permafrost prevents water from draining into water reservoirs. However, the degradation of permafrost in response to warming is a long-term process that also enhances evapotranspiration. Thus, the degradation of the alpine grassland ecosystem on the Qinghai-Tibetan Plateau (releasing carbon) cannot be mainly attributed to the disappearing waterproofing function of permafrost. © 2014 IOP Publishing Ltd.


Li L.,Chongqing University | Li H.,Chongqing University | Xiang B.,Chongqing Meteorological Administration | Qin B.,Chongqing Meteorological Administration
Acta Meteorologica Sinica | Year: 2010

In order to obtain reliable and effective upland soil resistivity measurements, it is necessary to know how much time after the rain stops is required before making soil resistivity observations so that the influence of precipitation on the measurements can be eliminated. Based on the soil resistivity monitoring data at different depths obtained from the soil conductance automatic monitoring system using the triple-electrode method, and the precipitation data from the synchronous and automatic observing system in Hechuan County of Chongqing, this paper analyzed the effect of rain on the determination of upland soil resistivity measurement time. The results showed that the required interval time between the measurement and the termination of rain should be as follows: if the rainfall was less than 0.1 mm, the interval time was zero; the interval time was 24 h if the precipitation time was less than 1 h or the rainfall was 0.1-2.0 mm; the interval time was 72 h if the precipitation time was 2-10 h or the rainfall was within 2.1-5.0 mm; and the interval time of 72-232 h was observed when the precipitation time was 10-25 h or longer or the rainfall was 5.0-10.1 mm or larger. Relevant observations showed that the above conclusions were on the whole valid for different soil depths. On the other hand, the results indicated that the maximum variance ratio for the influence of precipitation on resistivity measurement was about 28.9%, and the average variance was about 3.9%. Moreover, a preliminary analysis also showed that the precipitation process time might play a more crucial role in the resistivity recovery time than the precipitation amount. It is also found that it is practically better to use the rank correlation method than the numerical correlation analysis method to determine the time break between the stop of rain and the time to carry out the soil resistivity measurement.


Han S.,Chongqing Meteorological Administration
Applied Mechanics and Materials | Year: 2011

By using the sunshine time data from 260 meteorological observation stations in Changjiang river valley from 1960 to 2009, the features of sunshine time in this area are studied. The results show that the highest sunshine time place is Qinghai-Tibet Plateau which is located in the source of the Changjiang river, and the sunshine time is about 2200-3000 h.a -1. The lowest sunshine time place is Sichuan Basin, and the sunshine time is about 1000-1600 h.a -1. The place of middle sunshine time is the midstream and down stream of Changjiang river, and the sunshine time is about 2000 h.a -1. There is a trend of decreasing with the sunshine time in zone 1, and the value is 54.2 h.10a -1. The decreasing value of zone 2 is 38.3h.10a -1. There is a trend of "rise first, down after" with sunshine time in zone 3. There is obvious seasonal difference in sunshine duration, with bigger decreasing amplitude in summer and winter than that in autumn. The variation trend of sunshine time is not obvious in spring. © (2011) Trans Tech Publications.

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