Asian outflow and trans‐Pacific transport of carbon monoxide and ozone pollution: An integrated satellite, aircraft, and model perspective

Abstract

[1] Satellite observations of carbon monoxide (CO) from the Measurements of Pollution in the Troposphere (MOPITT) instrument are combined with measurements from the Transport and Chemical Evolution Over the Pacific (TRACE-P) aircraft mission over the northwest Pacific and with a global three-dimensional chemical transport model (GEOS-CHEM) to quantify Asian pollution outflow and its trans-Pacific transport during spring 2001. Global CO column distributions in MOPITT and GEOS-CHEM are highly correlated (R 2 = 0.87), with no significant model bias. The largest regional bias is over Southeast Asia, where the model is 18% too high. A 60% decrease of regional biomass burning emissions in the model (to 39 Tg yr À1 ) would correct the discrepancy; this result is consistent with TRACE-P observations. MOPITT and TRACE-P also give consistent constraints on the Chinese source of CO from fuel combustion (181 Tg CO yr À1 ). Four major events of trans-Pacific transport of Asian pollution in spring 2001 were seen by MOPITT, in situ platforms, and GEOS-CHEM. One of them was sampled by TRACE-P (26-27 February) as a succession of pollution layers over the northeast Pacific. These layers all originated from one single event of Asian outflow that split into northern and southern plumes over the central Pacific. The northern plume (sampled at 6-8 km off California) had no ozone enhancement. The southern subsiding plume (sampled at 2-4 km west of Hawaii) contained a 8-17 ppbv ozone enhancement, driven by decomposition of peroxyacetylnitrate (PAN) to nitrogen oxides (NO x ). This result suggests that PAN decomposition in trans-Pacific pollution plumes subsiding over the United States could lead to significant enhancements of surface ozone.

Trace gas and aerosol interactions in the fully coupled model of aerosol‐chemistry‐climate ECHAM5‐HAMMOZ: 1. Model description and insights from the spring 2001 TRACE‐P experiment

“…[42] The model reproduces fairly well the vertical profiles of CO observed in the two regions (correlation coefficient > 0.8, Figure 3), but underestimates the observed concentrations in the boundary layer both in the northern and southern regions (mean absolute bias by 13% and 17%, respectively), which may be due to too low anthropogenic and biomass burning emissions in eastern Asia, as indicated also by previous evaluations of the TRACE-P campaign [e.g., Heald et al, 2003;Allen et al, 2004]. We find a correlation coefficient of 0.59 and 0.83 between simulated and observed NO and NO 2 concentrations, respectively.…”

Surface ozone background in the United States: Canadian and Mexican pollution influences

“…The scaled GEIA emissions for East Asia are consistent with TRACE-P aircraft observations in Asian outflow in 2001 (Heald et al, 2003), but NO x emissions in East Asia have grown rapidly since then (Zhang et al, 2007, Zhang et al, 2008. We also conducted a simulation using an (Zhang et al, 2007).…”

The role of horizontal model resolution in assessing the transport of CO in a middle latitude cyclone using WRF-Chem

“…Three primary mechanisms can loft pollutants from the boundary layer to the free troposphere: (1) airstreams such as the warm conveyor belt (WCB) that are associated with middle latitude cyclones (Bey et al, 2001;Cooper et al, 2002;Hannan et al, 2003;Kiley and Fuelberg, 2006), (2) orographic lifting (Henne et al, 2004;Chen et al, 2009;Ding610 C. A. Klich and H. E. Fuelberg: Transport of CO in a middle latitude cyclone latitudes (Stohl et al, 2002), distinct maxima are located off the east coasts of North America and Asia (Stohl, 2001;Eckhardt et al, 2004). The long-range synoptic-scale WCBrelated transport of atmospheric pollutants has been studied across both the Pacific Ocean (e.g., Jaffe et al, 1999;Yienger et al, 2000;Bey et al, 2001;Carmichael et al, 2003;Heald et al, 2003;Jacob et al, 2003;Liu et al, 2003;Cooper et al, 2004) and Atlantic Ocean (Stohl and Trickl, 1999;Cooper et al, 2001Cooper et al, , 2002Naja et al, 2003;Li et al, 2005;Fehsenfeld et al, 2006;Singh et al, 2009). Anthropogenic emissions across eastern Asia have been increasing rapidly (Richter et al, 2005;Ohara et al, 2007;Zhang et al, 2007Zhang et al, , 2009, and their transport to the western United States (US) has been shown to increase local surface ozone concentrations Fiore et al, 2002;Jaffe et al, 2004;Oltmans et al, 2008;Zhang et al, 2008;Reidmiller et al, 2009;…”