High levels of tropospheric (ground-level) ozone are well known to affect human health. Local ozone concentration is affected by the availability of its photochemical ingredients and meteorological conditions conducive to buildup or transport. Temperature and solar radiation are two of the most important meteorological elements affecting local ozone concentration.
While ... much work has related ozone concentration to meteorology (Rao et al. 1995; Solomon et al. 2000; Porter et al. 2001), little has been done on the climatological time scale (Cox and Chu 1996). Meteorologically-oriented, ground-level ozone research has focused mainly on improving daily forecasts of ozone concentrations (McHenry et al. 2004) or on determining trends and pinpointing the magnitude of reductions due to changes in regulations (Porter et el. 2001). However, the climatological time scale is also an important consideration as we learn more about climate variability and grow more interested in seasonal prediction (Kanamitsu et al. 2002).
The goal of this project was to develop a regional climatological index to ozone potential covering a 50-100 year period. Although many factors contributing to high ground-level ozone concentrations can be highly local in occurrence, regional-scale consistencies have been found (Wolff et al. 2001). Upscaling here, from station or city to region, is based on the model, often employed in snow hydrology, that temperature is a good integrator of many of the processes that affect snowmelt (Rango and Martinec 1995; Ohmura 2001) and, by extension, ground-level ozone concentrations: radiation balance, air movement, air mass stagnation.
Relationships between annual counts of days exceeding a threshold concentration and seasonal mean temperature and solar radiation are explored for the Northeast and Midwest U.S. regions. These relationships form the basis of a regional, population-weighted, climatic index to the potential for high ground-level ozone exposure.
Acknowledgments: Our research was funded by the NOAA National Climatic Data Center as part of their National Climate Impacts Indicators program. Discussions with Jay Lawrimore, Kelly Redmond, and Scott Sheridan were useful.
Open source software developers are also acknowledged, especially for the Python and R languages used for programming, mapping, and statistical analysis. For analysis, STATA was also helpful.
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Cox, W. M. and S.-H. Chu, 1996: Assessment of interannual ozone variation in urban areas from a climatological perspective. Atmos. Environ., 30, 2615-2625.
Heim, R. R., J. H. Lawrimore, D. B. Wuertz, A. M. Waple, and T. W. R. Wallace, 2003: The REDTI and MSI: Two new national climate impact indices. J. Appl. Meteor., 42, 1435-1442.
Kanamitsu, M., ... A Kumar, H. M. H. Juang, J. K. Schemm, W. Q. Fang, F. L. Yang, S. Y. Hong, P. T. Peng, W. Chen, S. Moorthi, and M. Ji, 2002: NCEP dynamical season forecast system 2000. Bull. Amer. Meteor. Soc., 83, 1019-1037.
Karl, T. R., R. W. Knight, D. R. Easterling, and R. G. Quayle, 1996: Indices of climatic change for the United States. Bull. Amer. Meteor. Soc., 77, 279-292.
McHenry, J. N., Ryan, W. F., N. L. Seaman, C. J. Coats, J. Pudykiewicz, S. Arunachalam, and J. M. Vukovich, 2004 - A real-time Eulerian photochemical model forecast system: Overview and initial ozone forecast performance in the Northeast US corridor. Bull. Amer. Meteor. Soc., 85, 525-548.
Ohmura, 2001: Physical basis for the temperature-based melt-index method. J. Appl. Meteor., 40, 753-761.
Petersen, M. S., P. J. Lamb, and K. E. Kunkel, 1995: Implementation of a semi-physical model for examining solar radiation in the Midwest. J. Appl. Meteor., 34, 1905-1915.
Porter, P. S., S. T. Rao, I. G. Zurbenko, A. M. Dunker, and G. T. Wolff, 2001: Ozone air quality over North America; Part II-An analysis of trend detection and attribution techniques. J. Air Waste Manage. Assoc., 51, 283-306.
Rango, A. and J. Martinec, 1995: Revisiting the degree-day method for snowmelt computations. Water Resour. Bull., 31, 657-669.
Rao, S. T., E. Zalewsky, and I. G. Zurbenko, 1995: Determining temporal and spatial variations in ozone air quality. J. Air Waste Manage. Assoc., 45, 57-61.
Solomon, P., E. Cowling, G. Hidy, and C. Furiness, 2000: Comparison of scientific findings from major ozone field studies in North America and Europe. Atmos. Environ., 34, 1885-1920.