scholarly journals Applicability of AIRS Monthly Mean Atmospheric Water Vapor Profiles over the Tibetan Plateau Region

2012 ◽  
Vol 29 (11) ◽  
pp. 1617-1628 ◽  
Author(s):  
Yuwei Zhang ◽  
Donghai Wang ◽  
Panmao Zhai ◽  
Guojun Gu

Abstract The research explores the applicability of the gridded (level 3) monthly tropospheric water vapor (version 5) retrievals from the Atmospheric Infrared Sounder (AIRS) instrument and the Advanced Microwave Sounding Unit (AMSU) on board the NASA Aqua satellite over the Tibetan Plateau by comparing them with carefully processed radiosonde data. Local correlation analyses indicate that below 200 hPa, the AIRS/AMSU monthly water vapor retrievals are highly consistent with radiosondes over the whole plateau region, especially in the southeastern part and between 300 and 600 hPa. Relative deviation analyses further show that the differences between monthly mean AIRS/AMSU water vapor retrieval data and radiosondes are, in general, small below 250 hPa, in particular between 300 and 600 hPa and in high-altitude areas. Combined with a further direct comparison between AIRS/AMSU water vapor vertical retrievals and radiosonde observations averaged over the entire domain, these results suggest that the gridded monthly AIRS/AMSU water vapor retrievals can provide a very good account of spatial patterns and temporal variations in tropospheric water vapor content in the Tibetan Plateau region, in particular below 200 hPa. However, differences between AIRS/AMSU retrievals and radiosondes are seen at various levels, in particular above the level of 250 hPa. Therefore, for detailed quantitative analyses of water budget in the atmosphere and the entire water cycle, AIRS/AMSU retrieval data may need to be corrected or trained using radiosondes. Two fitting functions are derived for warm and cold seasons, although the seasonal difference is generally small.

2017 ◽  
Vol 2017 ◽  
pp. 1-13 ◽  
Author(s):  
Yi Sun ◽  
Quanliang Chen ◽  
Ke Gui ◽  
Fangyou Dong ◽  
Xiao Feng ◽  
...  

Water vapor (WV) has a vital effect on global climate change. Using satellite data observed by AURA/MLS and ERA-Interim reanalysis datasets, the spatial distributions and temporal variations of WV were analyzed. It was found that high WV content in the UTLS over the southern Tibetan Plateau is more apparent in summer, due to monsoon-induced strong upward motions. The WV content showed the opposite distribution at 100 hPa, though, during spring and winter. And a different distribution at 121 hPa indicated that the difference in WV content between the northern and southern plateau occurs between 121 and 100 hPa in spring and between 147 and 121 hPa in winter. In the UTLS, it diminishes rapidly with increase in altitude in these two seasons, and it shows a “V” structure in winter. There has been a weak increasing trend in WV at 100 hPa, but a downtrend at 147 and 215 hPa, during the past 12 years. At the latter two heights, the WV content in summer has been much higher than in other seasons. Furthermore, WV variation showed a rough wave structure in spring and autumn at 215 hPa. The variation of WV over the Tibetan Plateau is helpful in understanding the stratosphere-troposphere exchange (STE) and climate change.


2021 ◽  
Author(s):  
Zhilan Wang ◽  
Meiping Sun ◽  
Xiaojun Yao ◽  
Lei Zhang ◽  
Hao Zhang

Abstract Based on radiosonde stations and V3.0 data, Atmospheric Infrared Sounder (AIRS)-only, Tropical Rainfall Measuring Mission satellite (TRMM) and MERRA2, and ERA-5 data, we evaluated the ability of each dataset to reproduce water vapor content and explored its relationship with precipitation and temperature over the Tibetan Plateau and its surroundings. The results showed that the southern part of the surrounding area had high water vapor content and a low water vapor content zone appeared in the inner part of the Tibetan Plateau. The largest water vapor content appeared in summer and the smallest in winter. Most of the products could capture the spatial distribution of water vapor content, ERA-5 had the smallest bias and the highest correlation coefficient with the radiosonde data. The water vapor content has shown a gradually increasing trend over the last 50 years, with the most obvious increase in summer. Several sets of products had the same fluctuation trend and value is greater than the radiosonde data. There was a significant positive correlation between air temperature and water vapor content in the Tibetan Plateau, especially in the south. As the latitude increased, the correlation between precipitation and water vapor content gradually decreased and a negative correlation appeared.


2018 ◽  
Vol 10 (01) ◽  
pp. 1850003
Author(s):  
Tyler C. Tucker ◽  
Samuel S. P. Shen

This research develops a toolkit for snow-cover area calculation and display (SACD) based on the Interactive Multisensor Snow and Ice Mapping System (IMS). The paper uses the Tibetan Plateau region as an example to describe the toolkit’s method, results, and usage. The National Snow and Ice Data Center (NSIDC) provides to the public IMS a well-used system for monitoring the snow and ice cover. The newly developed toolkit is based on a simple shoe-lace formula for a grid box area on a sphere and can be conveniently used to calculate the total area of snow cover given the IMS data. The toolkit has been made available as an open source Python software on GitHub. The toolkit generates the time series of the daily snow-covered area for any region over the Northern Hemisphere from 4 February 1997. The toolkit also creates maps showing snow and ice coverage with an elevation background. The Tibetan Plateau (TP) region [Formula: see text]–[Formula: see text]N)[Formula: see text][Formula: see text]–[Formula: see text]E) is used as an example to demonstrate our work on SACD. The IMS products at 24, 4, and 1[Formula: see text]km resolutions include each grid’s latitude and longitude coordinates that are used to calculate the grid box’s area using the shoe-lace formula. The total TP area calculated by the sum of the areas of all the grid boxes approximates the true spherical TP surface area bounded by [Formula: see text]–[Formula: see text]N) [Formula: see text]–[Formula: see text]E) with a difference 0.046% for the 24[Formula: see text]km grid and 0.033% for the 4[Formula: see text]km grid. The differences in the snow-cover area reported by the 24[Formula: see text]km and 4[Formula: see text]km grids vary between [Formula: see text]% and 6.24%. The temporal variations of the daily TP snow cover are displayed in time series from 4 February 1997 to present with 4[Formula: see text]km and 24[Formula: see text]km resolutions.


2021 ◽  
Vol 13 (22) ◽  
pp. 4676
Author(s):  
Deli Meng ◽  
Wanjiao Song ◽  
Qing Dong ◽  
Zi Yin ◽  
Wenbo Zhao

The Tibetan Plateau (TP), atmosphere, and Indo-Pacific warm pool (IPWP) together constitute a regional land–atmosphere–ocean water vapor transport system. This study uses remote sensing data, reanalysis data, and observational data to explore the spatiotemporal variations of the summer atmospheric water cycle over the TP and its possible response to the air-sea interaction in the IPWP during the period 1958–2019. The results reveal that the atmospheric water cycle process over the TP presented an interannual and interdecadal strengthening trend. The climatic precipitation recycle ratio (PRR) over the TP was 18%, and the stronger the evapotranspiration, the higher the PRR. On the interdecadal scale, the change in evapotranspiration has a significant negative correlation with the Pacific Decadal Oscillation (PDO) index. The variability of the water vapor transport (WVT) over the TP was controlled by the dynamic and thermal conditions inside the plateau and the external air-sea interaction processes of the IPWP. When the summer monsoon over the TP was strong, there was an anomalous cyclonic WVT, which increased the water vapor budget (WVB) over the TP. The central and eastern tropical Pacific, the maritime continent and the western Indian Ocean together constituted the triple Sea Surface Temperature (SST) anomaly, which enhanced the convective activity over the IPWP and induced a significant easterly wind anomaly in the middle and lower troposphere, and then generated pronounced easterly WVT anomalies from the tropical Pacific to the maritime continent and the Bay of Bengal. Affected by the air-sea changes in the IPWP, the combined effects of the upstream strengthening and the downstream weakening in the water vapor transport process, directly and indirectly, increased the water vapor transport and budget of TP.


2015 ◽  
Vol 8 (11) ◽  
pp. 11925-11952
Author(s):  
S. Wu ◽  
G. Dai ◽  
X. Song ◽  
B. Liu ◽  
L. Liu

Abstract. The water vapor expedition experiment campaign was operated in the Tibetan Plateau during July and August 2014, by utilizing the Water vapor, Cloud and Aerosol Lidar (WACAL). The observation was carried out in Nagqu area (31.5° N, 92.05° E), which is 4508 m above the mean sea level. During the observation, the water vapor mixing ratio at high elevation was obtained. In this paper, the methodology of the WACAL and the retrieval method are presented in particular. The validation of water vapor mixing ratio measured during the field campaigns is completed by comparing the Lidar measurements to the radiosonde data. WACAL observations from July to August illustrate the diurnal variation of water vapor mixing ratio in the planetary boundary layer in this high elevation area. The mean water vapor mixing ratio in Nagqu in July and August is about 9.4 g kg−1 and the values vary from 6.0 to 11.7 g kg−1 near ground. The SNRs and relative errors of the data are analyzed and discussed as well in this paper. Finally, combining the vertical wind speed profiles measured by the coherent wind lidar, the vertical flux of water vapor is calculated and the upwelling and deposition of the water vapor are monitored. It is the first application, to our knowledge, to operate continuously atmospheric observation by utilizing multi-disciplinary lidar at altitude higher than 4000 m which is significant for research on the boundary dynamics and meteorology of Tibetan Plateau.


2020 ◽  
Author(s):  
Hongru Yan ◽  
Jianping Huang ◽  
Yongli He ◽  
Yuzhi Liu ◽  
Tianhe Wang ◽  
...  

2014 ◽  
Vol 112 ◽  
pp. 79-91 ◽  
Author(s):  
Kun Yang ◽  
Hui Wu ◽  
Jun Qin ◽  
Changgui Lin ◽  
Wenjun Tang ◽  
...  

Author(s):  
Shan Lin ◽  
Genxu Wang ◽  
Zhaoyong Hu ◽  
Kewei Huang ◽  
Xiangyang Sun ◽  
...  

AbstractIn this study, the spatiotemporal changes and driving factors of evapotranspiration (ET) over the Tibetan Plateau (TP) are assessed from 1961-2014, based on a revised generalized nonlinear complementary (nonlinear-CR) model. The average annual ET on the TP was 328 mm/year. The highest ET value (711 mm/year) was found in the forest region in the southeastern part of the TP, and the lowest value (151 mm/year) was found in the desert region in the northwestern part of the TP. In terms of the contribution of different sub-regions to the total amount of ET for the whole plateau, the meadow and steppe regions contributed the most to the total amount of ET of TP, accounting for 30% and 18.5%, respectively. The interannual ET presented a significant increasing trend with a value of 0.26 mm/year from 1961 to 2014, and a significant positive ET trend was found over 35% of the region, mainly in the southeastern part of the plateau. The increasing trend of ET in swamp areas was the largest, while that in the desert areas was the smallest. In terms of the seasonality, the ET over the plateau and different land-cover regions increased the most in summer, followed by spring, while the change in ET in winter was not obvious. The energy factors dominated the long-term change in the annual ET over the plateau. In addition, the available energy is the controlling factor for ET changes in humid areas such as forests and shrublands. Energy and water factors together dominate the ET changes in arid areas.


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