The Radiometric Sensitivity Requirements for Satellite Microwave Temperature Sounding Instruments for NWP

TitleThe Radiometric Sensitivity Requirements for Satellite Microwave Temperature Sounding Instruments for NWP
Publication TypeTechnical memorandum
Date Published02/2009
Secondary TitleECMWF Technical Memorandum
Number583
AuthorsBell, W, Di Michele, S, Bauer, P, McNally, A, English, SJ, Atkinson, N, Charlton, J
PublisherECMWF
Abstract

The sensitivity of NWP forecast accuracy with respect to the radiometric performance of microwave sounders is assessed through a series of observing system experiments at the Met Office and ECMWF. The observing system experiments compare the impact of normal data from a single AMSU with that from an AMSU where synthetic noise has been added. The results show a measurable reduction in forecast improvement in the southern hemisphere with improvements reduced by 11% for relatively small increases in radiometric noise (NEDT increased from 0.1 to 0.2 K for remapped data). The impact of microwave sounding data is shown to be significantly less than was the case prior to the use of advanced infrared sounder data (AIRS and IASI) with microwave sounding data now reducing Southern Hemisphere forecast errors by approximately 10% compared to 40% in the pre-AIRS/IASI period.

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