Global and zonal total ozone variations estimated from ground‐based and satellite measurements: 1964–2000

Abstract

[1] Six data sets of monthly average zonal total ozone were intercompared and then used to estimate latitudinal and global total ozone temporal variations and trends. The data sets were prepared by different groups and are based on TOMS, SBUV-SBUV/2, GOME, and ground-based measurements. Different approaches have been used to homogenize the records over the period 1979-2000. Systematic differences of up to 3% were found between different data sets for zonal and global total ozone area weighted average values. However, when these systematic differences were removed by deseasonalizing the data, the residuals agreed to within ±0.5% of the long-term mean ozone values. All data sets show changes in the rate of the total ozone decline in recent years. While global ozone was fairly constant during the 1990s, the average values of the 1990s are about 2-3% lower than those of the late 1970s. About 38% of the global ozone is located between 25°S and 25°N where the data show no decline. The strongest decline and the largest variability occur over the 35°N-60°N zone during the winter-spring season with the largest negative deviations occurring in 1993 and 1995. The decline in autumn is much smaller at these latitudes. Over the 35°S-60°S zone the ozone decline shows less seasonal dependence, and the largest deviations there were observed in 1985 and 1997. Sliding 11-year trends were calculated to estimate ozone changes over different time intervals

Middle atmosphere response to the solar cycle in irradiance and ionizing particle precipitation

“…Figure 23 presents the zonal mean total column ozone variation with latitude. The high latitude effect of EPP is most apparent in the SH where the maximum in total column ozone variation near the pole is removed and is lower than in the ground based observations (Fioletov et al, 2002, latest data provided courtesy of V. Fioletov). This may reflect an overly stable SH polar vortex in CMAM.…”

“…For 1979 conditions there is a dynamical ozone "hole" in the SH polar region in both the observations and the model. The annual mean total column ozone in the SH polar region exhibits a distinct minimum of about 285 DU in the ground based observations (Fioletov et al, 2002) and 250 DU in the model. A maximum of about 340 DU occurs at 55 • S. This structure persists from year to year in the model and observations, except that in the case of the latter the increasing halogen burden lowers the total column ozone amount globally.…”

“…To take into account the spectral variability of the solar radiation, both the solar heating and photolysis rates schemes have been modified. Absorption of solar UV radiation at wavelengths shorter than 300 nm by ozone and molecular oxygen provides the main contribution to the solar heating of the middle atmosphere (e.g., Fomichev, 2009). This means that in order to simulate effects of solar variability in the middle atmosphere, the spectral resolution of the model radiation scheme should be high enough so that it allows for an adequate description of variations in the spectral solar irradiance (SSI) over the solar cycle evolution (e.g., Egorova et al, 2004;Nissen et al, 2007).…”

Comparison of profile total ozone from SBUV (v8.6) with GOME-type and ground-based total ozone for a 16-year period (1996 to 2011)

“…However, the absence of data over vast regions (e.g., oceans) and sensitivity to individual instrument errors is an important factor, particularly in the tropical region and the Southern Hemisphere where the number of stations is very limited. Comparisons of global and zonal ozone variations from ground-based and satellite measurements for the period 1964-2000 were presented by Fioletov et al (2002). The ground-based multi-year total ozone record used in this study is the recently updated one extending through November 2012.…”

Numerical Modeling of Climate-Chemistry Connections: Recent Developments and Future Challenges

“…Colored lines: The baselineadjusted individual model trends; red vertical dashed line: year when the multi-model trend in total column ozone (left) and Cl y at 50 hPa (right) returns to 1980 values; blue vertical dashed lines: uncertainty in these return dates; black dotted lines in the left panels: observed total column ozone, where a linear least square regression model was used to remove the effects of the quasi-biennial oscillation, solar cycle, El Niño-Southern Oscillation, and volcanoes from four observational data sets. The observations include ground-based measurements (updated from [47]), merged satellite data [48], the National Institute of Water and Atmospheric Research (NIWA) combined total column ozone database [49], and Solar Backscatter Ultraviolet (SBUV, SBUV/2) retrievals (updated from [50]). The observational time series is shifted vertically so that it equals 0 in 1980.…”