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Development of a ground-based microwave radiometer for retrieval of water vapor profiles of the middle atmosphere and determination of atmospheric opacity

Grant number: 01/02336-9
Support type:Scholarships in Brazil - Post-Doctorate
Effective date (Start): August 01, 2001
Effective date (End): July 31, 2004
Field of knowledge:Physical Sciences and Mathematics - Astronomy - Astronomical Instrumentation
Cooperation agreement: DAAD
Principal Investigator:Zulema Abraham
Grantee:Hermann Josef Berg
Home Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil
Associated research grant:00/06769-4 - The Galaxy and Star Formation, AP.TEM

Abstract

The objective of the proposed project is to develop, test and operate a high precision water vapor radiometer (WVR). The WVR will be a ground-based, passive heterodyne receiver that detects the centimeter wave emission of atmospheric water molecules. Altitude profiles of the volume mixing ratio of water vapor in the middle atmosphere (20-80 km) will be inverted from the shape of the detected spectral line at 22 GHz. Total column amounts of water vapor, cloud liquid water and the atmospheric opacity can be determined from elevation scans and by broadband measurements of a supplementary channel at 32 GHz. Due to the influence of water vapor on the propagation of electromagnetic waves, detailed data are strongly demanded for radio astronomy. Furthermore water vapor is the key gas that dominates weather and climate. It plays an important role in the dynamics, the radiative balance and the chemistry of the atmosphere ("ozone hole", "global change"). The results gathered by the WVR will contribute substantially to the field of aeronomy and are very important for the understanding of short term, daily and seasonal atmospheric opacity variations, from centimeter to submillimeter wavelengths. (AU)