A 5‐year evaluation of the representativeness of the tropospheric ozone residual at nonclimatological periods

Abstract

Daily values, monthly averages, and seasonal averages of the tropospheric ozone residual (TOR) were estimated using the Total Ozone Mapping Spectrometer (TOMS) and the Solar Backscattered Ultraviolet (SBUV) data for the five‐year period 1985–1989. Comparisons were made at these various timescales between TOR and tropospheric ozone using data from eight ozonesonde stations within the region 50°N to 50°S and between normalized departures of the TOR and surface ozone data averaged over four 5° latitude by 5° longitude squares within the eastern United States. These comparisons were accomplished to determine the usefulness of the TOR to represent tropospheric ozone at nonclimatological periods. The results indicated that the annual cycle of the TOR determined using monthly and seasonally averaged values provides a realistic depiction of the annual cycle of tropospheric ozone in the northern hemisphere; that is, approximately a 2% mean error and an 81% correlation. However, in a limited number of comparisons (Hilo and Natal), the annual cycle of the TOR represented the annual cycle of tropospheric ozone at tropical latitudes poorly; that is, approximately a 38% mean error and a 59% correlation.