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Proceedings Paper

IASI hyperspectral radiances in the NCMRWF 4D-VAR assimilation system: OSE
Author(s): Priti Sharma; Indira Rani S.; Swapan Mallick; D. Srinivas; John P. George; Munmun Dasgupta
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Paper Abstract

Accuracy of global NWP depends more on the contribution of satellite data than the surface based observations. This is achieved through the better usage of satellite data within the data assimilation system. Efforts are going on at NCMRWF to add more and more satellite data in the assimilation system both from Indian and international satellites in geostationary and polar orbits. Impact of the new dataset is assessed through Observation System Experiments (OSEs), through which the impact of the data is evaluated comparing the forecast output with that of a control run. This paper discusses one such OSEs with Infrared Atmospheric Sounder Interferometer (IASI) onboard MetOp-A and B. IASI is the main payload instrument for the purpose of supporting NWP. IASI provides information on the vertical structure of the atmospheric temperature and humidity with an accuracy of 1K and a vertical resolution of 1 km, which is necessary to improve NWP. IASI measures the radiance emitted from the Earth in 8641 channels, covering the spectral interval 645-2760 cm-1. The high volume data resulting from IASI presents many challenges, particularly in the area of assimilation. Out of these 8641 channels, 314 channels are selected depending on the relevance of information in each channel to assimilate in the NCMRWF 4D-VAR assimilation system. Studies show that the use of IASI data in NWP accounts for 40% of the impact of all satellite observations in the NWP forecasts, especially microwave and hyperspectral infrared sounding techniques are found to give the largest impacts

Paper Details

Date Published: 30 April 2016
PDF: 7 pages
Proc. SPIE 9880, Multispectral, Hyperspectral, and Ultraspectral Remote Sensing Technology, Techniques and Applications VI, 98800P (30 April 2016); doi: 10.1117/12.2225868
Show Author Affiliations
Priti Sharma, National Ctr. for Medium Range Weather Forecasting (India)
Indira Rani S., National Ctr. for Medium Range Weather Forecasting (India)
Swapan Mallick, National Ctr. for Medium Range Weather Forecasting (India)
D. Srinivas, National Ctr. for Medium Range Weather Forecasting (India)
John P. George, National Ctr. for Medium Range Weather Forecasting (India)
Munmun Dasgupta, National Ctr. for Medium Range Weather Forecasting (India)


Published in SPIE Proceedings Vol. 9880:
Multispectral, Hyperspectral, and Ultraspectral Remote Sensing Technology, Techniques and Applications VI
Allen M. Larar; Prakash Chauhan; Makoto Suzuki; Jianyu Wang, Editor(s)

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