图书馆知识库

Ground-based observations (2014-2015) indicated that the precipitable water vapor (PWV) values in China exhibited large spatial and temporal variations. The annual mean PWV values ranged from 4.0 +/- 2.9 mm to 42.3 +/- 10.6 mm from the Qinghai-Tibet Plateau to the South China Sea, and the seasonal variation ranged from 1.9 +/- 1.2 mm to 50.5 +/- 5.4 mm. The PWV values were retrieved from MODIS, VIRR and MERSI data, and the accuracies varied widely with relative errors from 10% to 899%. VIRR performed the best in the humid southern coastal regions of China (R = 93%) where the annual PWV was as high as 35 mm. MERSI was more suitable in the dry western region of China (R = 84%) where the average PWV value was lower than 15 mm. MODIS PWV products could be used to accurately observe the PWV in the city and urbanized areas of the eastern China Plain (R = 89%) where the annual mean PWV was 20-30 mm. All of the products yielded larger errors in the summer than in the winter. The MOD05 and MOD07 data performed better than the other satellite data in most regions.