A new ENSO index derived from satellite measurements of column ozone
Open Access
- 21 April 2010
- journal article
- Published by Copernicus GmbH in Atmospheric Chemistry and Physics
- Vol. 10 (8), 3711-3721
- https://doi.org/10.5194/acp-10-3711-2010
Abstract
Column Ozone measured in tropical latitudes from Nimbus 7 total ozone mapping spectrometer (TOMS), Earth Probe TOMS, solar backscatter ultraviolet (SBUV), and Aura ozone monitoring instrument (OMI) are used to derive an El Nino-Southern Oscillation (ENSO) index. This index, which covers a time period from 1979 to the present, is defined as the "Ozone ENSO Index" (OEI) and is the first developed from atmospheric trace gas measurements. The OEI is constructed by first averaging monthly mean column ozone over two broad regions in the western and eastern Pacific and then taking their difference. This differencing yields a self-calibrating ENSO index which is independent of individual instrument calibration offsets and drifts in measurements over the long record. The combined Aura OMI and MLS ozone data confirm that zonal variability in total column ozone in the tropics caused by ENSO events lies almost entirely in the troposphere. As a result, the OEI can be derived directly from total column ozone instead of tropospheric column ozone. For clear-sky ozone measurements a +1 K change in Nino 3.4 index corresponds to +2.9 Dobson Unit (DU) change in the OEI, while a +1 hPa change in SOI coincides with a −1.7 DU change in the OEI. For ozone measurements under all cloud conditions these numbers are +2.4 DU and −1.4 DU, respectively. As an ENSO index based upon ozone, it is potentially useful in evaluating climate models predicting long term changes in ozone and other trace gases.Keywords
This publication has 25 references indexed in Scilit:
- Effects of the 2006 El Niño on tropospheric ozone and carbon monoxide: implications for dynamics and biomass burningAtmospheric Chemistry and Physics, 2009
- Wave fluxes of equatorial Kelvin waves and QBO zonal wind forcing derived from SABER and ECMWF temperature space-time spectraAtmospheric Chemistry and Physics, 2009
- Effects of the 2006 El Niño on tropospheric composition as revealed by data from the Tropospheric Emission Spectrometer (TES)Geophysical Research Letters, 2008
- Space‐based constraints on the production of nitric oxide by lightningJournal of Geophysical Research: Solid Earth, 2007
- Tropical tropospheric ozone: Implications for dynamics and biomass burningJournal of Geophysical Research: Solid Earth, 2002
- Lower‐Tropospheric Ozone (LTO) derived from TOMS near mountainous regionsJournal of Geophysical Research: Solid Earth, 2001
- Tropospheric ozone enhancements during the Indonesian Forest Fire Events in 1994 and in 1997 as revealed by ground‐based observationsGeophysical Research Letters, 1999
- An analysis of ozonesonde data for the troposphere: Recommendations for testing 3‐D models and development of a gridded climatology for tropospheric ozoneJournal of Geophysical Research: Solid Earth, 1999
- Effects of 1997–1998 El Niño on tropospheric ozone and water vaporGeophysical Research Letters, 1998
- Modulation of middle and upper tropospheric ozone at northern midlatitudes by the El Niño/Southern OscillationGeophysical Research Letters, 1998