Impact of Climate Change on the Frequency and Intensity of Low-Level Temperature Inversions in California

摘要

Concentration of several key air pollutants (ozone, secondary particulate matter) depend strongly upon the vertical gradient of temperature (e.g. inversion strength) in the lower atmosphere. Variations in inversion strength and other inversion characteristics in California are driven by natural processes over time scales from synoptic to decadal periods, and can be investigated using observational records over the past several decades. Additionally, virtually all climate model projections indicate that California's climate will warm as greenhouse gases continue to accumulate in the atmosphere. Based upon recent runs over a variety of models and greenhouse gas emissions scenarios, potential warming over California during the 21st Century would range from about 2 degrees C to 5 degrees C (change of temperatures in 2100 relative to recent 1961-1990 historical climatology). Because the magnitude of these changes may rival or exceed the magnitude of natural year-to-year climate variability in California, these changes could have significant consequences on the production and buildup of air pollutants in California's air basins. Thus, a better understanding of future changes in the temperature structure, including low level inversions and the associated atmospheric structure is crucial to preparing for regional air quality problems in California over the next several decades.