Algorithms for estimation of air-specific humidity using TMI data

• Published in: International journal of remote sensing Vol. 33; no. 23; pp. 7413 - 7430
• Main Authors: Iwasaki, Shinsuke, Kubota, Masahisa
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Abingdon Taylor & Francis 01.01.2012
• Subjects: algorithms; Animal, plant and microbial ecology; Applied geophysics; Biological and medical sciences; data collection; Earth sciences; Earth, ocean, space; Exact sciences and technology; Fundamental and applied biological sciences. Psychology; General aspects. Techniques; humidity; Internal geophysics; rain; Teledetection and vegetation maps; temperature; atmosphere; microwaves; algorithms; data; tropical zone; air; Result; Relation; 2006; Polarized radiation; 2003; humidity; International; Heathland and moor; rainfall; Small; Estimation; Empirical method; Imager; in situ; brightness temperature; channels; marine environment; ocean; regression
• ISSN: 1366-5901; 0143-1161; 1366-5901
• DOI: 10.1080/01431161.2012.685974

We developed two empirical algorithms for estimating the surface air-specific humidity (Qₐ) at 10 m over the ocean using Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) brightness temperature data. We used the in situ data included in the International Comprehensive Ocean-Atmosphere Data Set for 2003–2006 as true values in this study. We estimated the Qₐ using the developed regression formulae and validated the results by comparing with moored buoy data. The biases of our product were relatively small, i.e. 0.03 and 0.29 g kg–¹ for TMI_4CH and TMI_9CH, respectively, when compared with other Qₐ retrievals. Moreover, we investigated the relationship between the brightness temperature observed by each channel and the in situ Qₐ. We concluded that the use of the brightness temperature determined by the 85 GHz polarized radiation can considerably reduce the bias.