Improvement of Remote Sensing Techniques in TPW Assessment Using Radiosonde Data

• Published in: Journal of applied sciences (Asian Network for Scientific Information) Vol. 8; no. 3; pp. 480 - 488
• Main Authors: Mobasheri, M.R., Purbagher, S.M., Farajzadeh, M., Sadeghi Na, A.
• Format: Journal Article
• Language: English
• Published: 01.02.2008
• Subjects: Iran; Iran, Tehran
• ISSN: 1812-5654
• DOI: 10.3923/jas.2008.480.488

A great amount of efforts have so far been devoted to the global determination of Total Precipitable Water (TPW) but little work is directed toward the regional assessment of TPW using remote sensing techniques. To increase the level of confidence in TPW assessment in the local to regional scale using satellite imageries, a simultaneous in situ measurement by radiosonde and satellite over passing were carried out. The results show a high correlation (0.93) between radiosondes data and the ratio of the two absorption band (narrow band to a wide band). This in MODIS sensor is the ratio of channel 18 to channel 19. It is found that the application of different algorithms via classification of the atmosphere by its water vapor content and definition of threshold values for TPW, may not work in the confined regions such as Tehran capital city of Iran. The result of this study is presented through a conversion equation like TPW (Real) = a.TPW sub(18/19) + b. More work is required to evaluate applicability of this equation for different seasons and different states of the atmosphere.