Impact of the assimilation of ozone from the Tropospheric Emission Spectrometer on surface ozone across North America

Abstract

We examine the impact of assimilating ozone observations from the Tropospheric Emission Spectrometer (TES) on North American surface ozone abundances in the GEOS‐Chem model in August 2006. The assimilation reduces the negative bias in the modeled free tropospheric ozone, which enhances the ozone flux into the boundary layer. Surface ozone abundances increased by as much as 9 ppb in western North America and by less than 2 ppb in the southeast, resulting in a total background source of ozone of 20–40 ppb. The enhanced ozone in the model reduced the model bias with respect to surface ozone observations in the western USA, but exacerbated it in the east. This increase in the bias in the boundary layer in the east, despite the agreement between the assimilation and ozonesonde measurements in the free troposphere, suggests errors in the ozone sources or sinks or in boundary layer mixing in the model.

Sources of variations in total column carbon dioxide

“…We sum these three components to determine CO 2 . AM2 has not been used extensively in tracer transport studies (Parrington et al, 2009). To evaluate its performance, we compare CO 2 fields from AM2 with CO 2 generated with the TM5 tracer transport model underlying CarbonTracker using identical fluxes.…”

Simultaneous assimilation of satellite NO<sub>2</sub>, O<sub>3</sub>, CO, and HNO<sub>3</sub> data for the analysis of tropospheric chemical composition and emissions

“…VOCs). Parrington et al (2009) demonstrated that the changes in the O 3 flux from the free troposphere into the planetary boundary layer (PBL) by the TES O 3 assimilation reduces the positive bias in the PBL indirectly over North America. Although this effect is not confirmed by our global analysis, it is of interest to survey the detailed spatial distributions resulting from the data assimilation.…”

Construction of non-diagonal background error covariance matrices for global chemical data assimilation

“…Suboptimal Kalman filters have been employed successfully for chemical data assimilation Lamarque et al, 2002;Segers et al, 2005;Clark et al, 2006;Pierce et al, 2007;Parrington et al, 2009). The use of the ensemble Kalman filter (EnKF) in chemical data assimilation has been studied in Constantinescu et al (2007b,c,d).…”