Retrieval of ozone and nitrogen dioxide concentrations from Stratospheric Aerosol and Gas Experiment III (SAGE III) measurements using a new algorithm

Abstract

[1] We describe a new inversion algorithm developed for the retrieval of atmospheric constituents from Stratospheric Aerosol and Gas Experiment III (SAGE III) solar occultation measurements. The methodology differs from the operational (NASA) algorithm in several important ways. Our algorithm takes account of the finite altitude and spectral resolution of the measurements by integrating over the viewing window spectrally and spatially. We solve the problem nonlinearly by using optimal estimation theory, and we use an aerosol parameterization scheme based on eigenvectors derived from existing empirical and modeled information about their microphysical properties. The first four of these eigenvectors are employed in the retrieval algorithm to describe the spectral variation of the aerosol extinction. We retrieve ozone and nitrogen dioxide number densities and aerosol extinction from transmission measurements at 41 channels from 0.29 to 1.55 mm. In this paper we describe the results of the gas retrievals. Numerical simulations test the accuracy of the scheme, and subsequent retrievals from SAGE III transmission data for the period between May and October 2002 produce profiles of O 3 and NO 2 . Comparisons of the O 3 and NO 2 profiles with those obtained using the SAGE III operational algorithm and with those from independent measurements made by satellites, ozonesondes, and lidar indicate agreement in ozone measurements in the middle and upper stratosphere significantly closer than the natural variability and agreement in the lower stratosphere and upper troposphere approximately equal to the natural variability.

Electron density profiles in the quiet lower ionosphere based on the results of modeling and experimental data

“…Measurements (Zommerfields et al, 1989;Fussen et al, 2000;Kaufmann et al, 2003;Polyakov et al, 2005) and theoretical investigations Laird, 1970, 1972;Thomas and Bowman, 1972;Zadorozhny, 1982;Rodrigo et al, 1986;Sandor et al, 1997) show substantial diurnal variations of ozone concentration with maximum values at nighttime. Theoretical values of ozone numerical density are rather close to experimental values.…”

Comparison and synergy of stratospheric ozone measurements by satellite limb sounders and the ground-based microwave radiometer SOMORA

“…In the first part, the SOMORA data set is utilized for a cross-validation of the satellite experiments Aura/MLS , ENVISAT/MIPAS (Glatthor et al, 2006;Steck et al, 2006), ENVISAT/GOMOS (Meijer et al, 2004), SAGE-II (Nazaryan et al, 2005), SAGE-III (Polyakov et al, 2005), and UARS/HALOE (Brühl et al, 1996). The references above correspond to previous ozone validation studies of the satellite experiments.…”

Towards validation of SCIAMACHY lunar occultation NO2 vertical profiles

“…These validation results show that the agreement between the two instruments from 25 to 42 km is within 10% and below 25 km the HALOE NO 2 profiles are much lower, with relative differences of up to about 40%. HALOE NO 2 profiles were compared with correlative SAGE III measurements Polyakov et al (2005). Polyakov et al (2005) showed that HALOE NO 2 concentrations were lower than SAGE III results below 24 km and between 24 and 30 km HALOE NO 2 were higher than SAGE III results.…”

“…HALOE NO 2 profiles were compared with correlative SAGE III measurements Polyakov et al (2005). Polyakov et al (2005) showed that HALOE NO 2 concentrations were lower than SAGE III results below 24 km and between 24 and 30 km HALOE NO 2 were higher than SAGE III results. The relative mean deviations reported in Polyakov et al (2005) Fig.…”