We use long-term, coincident O 3 and temperature measurements at the regionally representative US Environmental Protection Agency Clean Air Status and Trends Network (CASTNet) over the eastern US from 1988 through 2009 to characterize the surface O 3 response to year-to-year fluctuations in weather, for the purpose of evaluating global chemistry-climate models. We first produce a monthly climatology for each site over all available years, defined as the slope of the best-fit line (m O3-T) between monthly average values of maximum daily 8-hour average (MDA8) O 3 and monthly average values of daily maximum surface temperature (T max). Applying two distinct statistical approaches to aggregate the site-specific measurements to the regional scale, we find that summer time m O3-T is 3-6ppbK -1 (r=0.5-0.8) over the Northeast, 3-4ppbK -1 (r=0.5-0.9) over the Great Lakes, and 3-6ppbK -1 (r=0.2-0.8) over the Mid-Atlantic. The Geophysical Fluid Dynamics Laboratory (GFDL) Atmospheric Model version 3 (AM3) global chemistry-climate model generally captures the seasonal variations in correlation coefficients and m O3-T despite biases in both monthly mean summertime MDA8 O 3 (up to-+10 to-+30ppb) and daily T max (up to-+5K) over the eastern US. During summer, GFDL AM3 reproduces m O3-T over the Northeast (m O3-T=2-6ppbK -1; r=0.6-0.9), but underestimates m O3-T by 4ppbK -1 over the Mid-Atlantic, in part due to excessively warm temperatures above which O 3 production saturates in the model. Combining T max biases in GFDL AM3 with an observation-based m O3-T estimate of 3ppbK -1implies that temperature biases could explain up to 5-15ppb of the MDA8 O 3 bias in August and September though correcting for excessively cool temperatures would worsen the O 3 bias in June. We underscore the need for long-term, coincident measurements of air pollution and meteorological variables to develop process-level constraints for evaluating chemistry-climate models used to project air quality responses to climate change. © 2011.
CITATION STYLE
Rasmussen, D. J., Fiore, A. M., Naik, V., Horowitz, L. W., McGinnis, S. J., & Schultz, M. G. (2012). Surface ozone-temperature relationships in the eastern US: A monthly climatology for evaluating chemistry-climate models. Atmospheric Environment, 47, 142–153. https://doi.org/10.1016/j.atmosenv.2011.11.021
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