BibTeX
@ARTICLE{
         Garcia2011Nin,
       author = "{Gimeno Garcia}, S. and Schreier, F. and Lichtenberg, G. and Slijkhuis, S.",
       title = "Near infrared nadir retrieval of vertical column densities: methodology and
         application to {SCIAMACHY}",
       journal = "Atmos. Meas. Tech.",
       volume = "4",
       number = "12",
       pages = "2633--2657",
       doi = "http://dx.doi.org/10.5194/amt-4-2633-2011",
       abstract = "Nadir observations with the shortwave infrared channels of SCIAMACHY on-board the
         ENVISAT satellite can be used to derive information on atmospheric gases such as CO, CH4 , N2O, CO2,
         and H2 O. For the operational level 1b-2 processing of SCIAMACHY data, a new retrieval code BIRRA
         (Beer InfraRed Retrieval Algorithm) has been de- veloped. BIRRA performs a nonlinear or separable
         least squares fit (with bound constraints optional) of the measured radiance, where molecular
         concentration vertical profiles are scaled to fit the observed data. Here we present the forward
         modeling (radiative transfer) and inversion (least squares op- timization) fundamentals of the code
         along with the further processing steps required to generate higher level products such as global
         distributions and time series. Moreover, vari- ous aspects of level 1 (observed spectra) and
         auxiliary input data relevant for successful retrievals are discussed. BIRRA is currently used for
         operational analysis of carbon mono- xide vertical column densities from SCIAMACHY channel 8
         observations, and is being prepared for methane retrievals using channel 6 spectra. A set of
         representative CO retrievals and first CH4 results are presented to demonstrate BIRRA’s
         capabilities.",
       ad_tools = "TAPENADE",
       ad_area = "Physics, Atmospheric remote sensing",
       year = "2011"
}