Spatiotemporal Variability of Non-Urban Ozone Concentrations Over the EasternUnited States and Its Potential Replication by Satellite Data

摘要

The spatial and temporal variability of the maximum 24 hourly surface ozoneconcentrations over the eastern United States was examined for the period 1985-1990 using Rotated Principal Component Analysis (RPCA). This led to the delineation of six contiguous subregions, each of which displayed statistically unique ozone characteristics. Examination of the time series associated with the Subregions revealed that the Great Lakes and Mid-Atlantic Subregions tend to contain a stronger seasonal cycle, with maximum concentrations occurring during the last week in June and the first week in July, respectively. The strength of this seasonality is weakened for the Northeast and South Subregions and the timing of its maximum delayed, until the end of July and the first of August, respectively. The Southwest Subregion experiences a greatly diminished seasonality, with maximum concentrations delayed until the middle of August. The seasonality found in the Florida Subregion is unique in both its strength and timing, as the highest concentrations consistently occur during the months of April and May. The time series were then deseasonalized and autocorrelations and spectral density estimates calculated, revealing that persistence is much more prevalent in the Florida, South and Southwest Subregions and less prevalent in the Northeast, Great Lakes and Mid-Atlantic Subregions.