Asian combustion sources and transpacific transport: An integration of satellite and in situ observations.

摘要

Industrialization of Asia will likely be one of the major drivers for changes in atmospheric composition in the future. Recent studies suggest that transpacific transport of Asian pollution has significant implications for air quality in the United States. In this thesis, tropospheric observations from space are linked with in situ observations and 3-D models to examine the mechanisms and impact of the intercontinental transport of these pollutants as well as the magnitude of their emission.; Satellite fire counts from AVHRR were used to develop a daily biomass burning emission inventory to improve model simulations of Asian outflow for the TRACE-P aircraft campaign.; Satellite observations of carbon monoxide (CO) from the MOPITT instrument were combined with measurements from the TRACE-P aircraft campaign (spring 2001), and with a global 3-D chemical transport model (GEOS-CHEM), to examine Asian pollution outflow and its transpacific transport. Four major events of transpacific transport were seen by MOPITT, in-situ platforms, and GEOS-CHEM, suggesting that satellites can be used to successfully monitor long-range pollution transport. One of these events was sampled by the TRACE-P aircraft demonstrating the first field observation of PAN decomposition driving O 3 production in polluted plumes transported to the remote troposphere.; Inverse modeling techniques were employed to compare the constraints on Asian sources of CO from MOPITT satellite observations, and TRACE-P aircraft observations. MOPITT observations provide greater information towards geographically disaggregating source regions within Asia. The MOPITT and TRACE-P observations are independently consistent in the constraints they provide on Asian CO sources, where biomass burning (anthropogenic) emissions are over-estimated (under-estimated) in bottom-up inventories.; MODIS satellite observations of aerosol optical thickness were used with the GEOS-CHEM model as well as ground station observations to characterize transpacific transport of Asian anthropogenic aerosols and determine their impact on particulate matter concentrations in the U.S. Sulfate observations at sites in the northwestern U.S. show evidence of Asian influence correlated with the model, both in events and in mean seasonal variation. Observations of high concentrations of organic carbon in the free troposphere cannot be reconciled with current model simulations, indicative of missing mechanisms for secondary organic aerosol formation.