Geophysical parameter retrieval and validation

The methodology for retrieval of atmospheric temperature and composition profiles, and surface thermal properties from observed radiance spectra is reported. These retrieval parameters are determined using a three-stage approach that combines three algorithms: (1) statistical physical-eigenvector-regression, (2) simultaneous non-linear matrix inversion, and (3) trace species profile enhancement. NAST-I aboard a high altitude aircraft has been successfully collecting data during many field campaigns. NAST-I provides relatively high spectral resolution (0.25 cm^-1) measurements in the spectral region of 645-2700 cm^-1 with moderate spatial resolution (a linear resolution equal to 13% of the aircraft altitude at nadir) and cross track scanning (producing a swath width on the Earth´s surface of approximately twice the aircraft altitude). Retrieval results from several NAST-I field campaigns are presented in conjunction with co-incident ground and in situ measurements for validation. These results demonstrate the ability of the NAST interferometer to reveal fine-scale horizontal features with relatively high vertical resolution.