Using satellite remote-sensing data for improving the description of air quality model

Accurate representations of photolysis rates in the photochemical modeling are of utmost importance. In the Community Multiscale Air Quality Modeling System (CMAQ), the method used for photolysis rate calculations depend on the correct estimation of spatially and temporally resolved actinic flux. The current actinic flux in CMAQ is calculated by parameterized variables related to surface albedo, total column ozone, aerosol, clouds, etc., which affect the attenuation of near ultraviolet and visible light. Remotely sensed satellite data provide synoptic and geospatial information with high spatial and temporal resolution, many of which are instrumental for improving the calculation of actinic flux in air quality models. In this study, we compile satellite derived quantities, including the Moderate Resolution Imaging Spectroradiometer (MODIS) Bidirectional Reflectance Distribution Function (BRDF)/Albedo product, the real-time total column ozone data from Total Ozone Mapping Spectrometer (TOMS), vertical ozone profiles retrieved from the recent version of Tropospheric Emission Spectrometer (TES), and TOMS aerosol optical depth data. These values are compared with the corresponding default parameters used in CMAQ for the central California region and the differences are documented. Sensitivity analysis is employed to further quantify the effects of changes in parameters of albedo, column ozone, and aerosol optical depths on photolysis rates and photochemical product concentrations.