Title :
Retrieval of total column methane concentration from IR sounding measurements
Author :
Smith, N. ; Weisz, E. ; Huang, H.-L. ; Annegarn, H.J.
Author_Institution :
Stellenbosch Univ., Stellenbosch
Abstract :
We present a general methodology and first results of total column trace gas retrievals from hyperspectral infrared observations. More specifically, we made use of a physical scheme to retrieve methane (CH4) profiles from atmospheric infrared sounder (AIRS) measurements. The method firstly required a forward calculation that maps the a priori state vector into measurement space, and for this we used the fast forward model, SARTA. Secondly, the calculation was inverted to derive at a posterior state of the atmosphere. We used gas profiles from the atmospheric chemistry experiment (ACE) together with ECMWF model fields for the assimilation of the state vector. ACE profiles were also used in the validation procedure. The retrievals were improved by up to 5% at the surface. Following the same scheme, we retrieved total column concentration of CH4 for an entire AIRS granule, thereby demonstrating its potential for use in operational air quality monitoring schemes at regional scales.
Keywords :
air pollution; atmospheric composition; organic compounds; remote sensing; ACE; AIRS; Atmospheric Chemistry Experiment; Atmospheric Infrared Sounder; ECMWF model; IR sounding measurements; SARTA fast forward model; air quality monitoring schemes; hyperspectral infrared observations; state vector assimilation; total column methane concentration; total column trace gas retrievals; Africa; Atmosphere; Atmospheric measurements; Atmospheric modeling; Chemistry; Extraterrestrial measurements; Geography; Infrared spectra; Jacobian matrices; Pollution measurement; Hyperspectral; finite differencing jacobians; infrared sounding; methane; physical retrieval; trace gases;
Conference_Titel :
Geoscience and Remote Sensing Symposium, 2007. IGARSS 2007. IEEE International
Conference_Location :
Barcelona
Print_ISBN :
978-1-4244-1211-2
Electronic_ISBN :
978-1-4244-1212-9
DOI :
10.1109/IGARSS.2007.4423828