Singular value decomposition analyses of tropical tropospheric ozone determined from TOMS

Abstract

A controversial dispute in space-based tropospheric ozone remote sensing is the puzzling discrepancy in the spatiotemporal distribution between residual-based satellite ozone observations and biomass-burning activity in the tropics during boreal winter. This study focuses on evaluation and analyses of two tropospheric ozone products determined from Earth Probe TOMS measurements: Convective Cloud Differential measurements (CCD) and Scan Angle measurements (SAM). Rather than using the typical station-to-station inter-comparison with ozone sounding measurements, the evaluation was performed at the global scale using temporal and spatial patterns derived from Singular Value Decomposition (SVD) analyses. The satellite observations of ozone precursors from MOPITT CO and GOME NO2 serve as markers identifying airmasses influenced by biomass burning. The SVD analyses reveal that the SAM tropospheric ozone product is remarkably consistent (95% significance level) with the two measured ozone precursors, CO and NO2, in distribution as well as in seasonality. The analyses provide compelling evidence that there is no discrepancy between tropospheric ozone and its precursors during boreal winter. Copyright 2008 by the American Geophysical Union.