A Large Annual Cycle in Ozone above the Tropical Tropopause Linked to the Brewer–Dobson Circulation

Near-equatorial ozone observations from balloon and satellite measurements reveal a large annual cycle in ozone above the tropical tropopause. The relative amplitude of the annual cycle is large in a narrow vertical layer between 16 and 19 km, with approximately a factor of 2 change in ozone between the minimum (during NH winter) and maximum (during NH summer). The annual cycle in ozone occurs over the same altitude region, and is approximately in phase with the well-known annual variation in tropical temperature. This study shows that the large annual variation in ozone occurs primarily because of variations in vertical transport associated with mean upwelling in the lower stratosphere (the Brewer–Dobson circulation); the maximum relative amplitude peak in the lower stratosphere is collocated with the strongest background vertical gradients in ozone. A similar large seasonal cycle is observed in carbon monoxide (CO) above the tropical tropopause, which is approximately out of phase with ozone (associated with an oppositely signed vertical gradient). The observed ozone and CO variations can be used to constrain estimates of the seasonal cycle in tropical upwelling.

[1]  J. Wallace,et al.  Structure of the Annual-Mean Equatorial Planetary Waves in the ERA-40 Reanalyses , 2007 .

[2]  Annmarie Eldering,et al.  Testing convective parameterizations with tropical measurements of HNO3, CO, H2O, and O3: Implications for the water vapor budget , 2006 .

[3]  Q. Fu,et al.  Impact of clouds on radiative heating rates in the tropical lower stratosphere , 2006 .

[4]  P. Bernath,et al.  Seasonal cycles of O3, CO, and convective outflow at the tropical tropopause , 2006 .

[5]  Q. Fu,et al.  The impact of cirrus clouds on tropical troposphere-to-stratosphere transport , 2006 .

[6]  Holger Vömel,et al.  Decreases in stratospheric water vapor after 2001: Links to changes in the tropical tropopause and the Brewer‐Dobson circulation , 2006 .

[7]  B. Duncan,et al.  The carbon monoxide tape recorder , 2006 .

[8]  W. Norton,et al.  Tropical Wave Driving of the Annual Cycle in Tropical Tropopause Temperatures. Part I: ECMWF Analyses , 2006 .

[9]  Peter H. Siegel,et al.  The Earth observing system microwave limb sounder (EOS MLS) on the aura Satellite , 2006, IEEE Transactions on Geoscience and Remote Sensing.

[10]  A. Sterl,et al.  The ERA‐40 re‐analysis , 2005 .

[11]  Peter F. Bernath,et al.  Atmospheric chemistry experiment (ACE): mission overview , 2004, SPIE Optics + Photonics.

[12]  L. Isaksen,et al.  The ERA-40 Reanalysis , 2004 .

[13]  J. Lamarque,et al.  Tropospheric ozone over the tropical Atlantic: A satellite perspective , 2003 .

[14]  Toshihiro Ogawa,et al.  Southern Hemisphere Additional Ozonesondes (SHADOZ) 1998–2000 tropical ozone climatology 2. Tropospheric variability and the zonal wave-one , 2003 .

[15]  Toshihiro Ogawa,et al.  Southern Hemisphere Additional Ozonesondes (SHADOZ) 1998–2000 tropical ozone climatology 1. Comparison with Total Ozone Mapping Spectrometer (TOMS) and ground-based measurements , 2003 .

[16]  Fei Wu,et al.  Thermal variability of the tropical tropopause region derived from GPS/MET observations , 2003 .

[17]  R. Garcia,et al.  Time-dependent upwelling in the tropical lower stratosphere estimated from the zonal-mean momentum budget , 2002 .

[18]  Rolf König,et al.  Atmosphere sounding by GPS radio occultation: First results from CHAMP , 2001 .

[19]  Jennifer A. Logan,et al.  An analysis of ozonesonde data for the lower stratosphere: Recommendations for testing models , 1999 .

[20]  J. Eluszkiewicz,et al.  The Brewer-Dobson Circulation: Dynamics of the Tropical Upwelling , 1999 .

[21]  J. Lamarque,et al.  Hemispheric asymmetries and seasonal variations of the lowermost stratospheric water vapor and ozone derived from , 1997 .

[22]  D. Fahey,et al.  Quantifying Transport Between the Tropical and Mid-Latitude Lower Stratosphere , 1996, Science.

[23]  M. Prather,et al.  Photochemical evolution of ozone in the lower tropical stratosphere , 1996 .

[24]  K. Rosenlof Seasonal cycle of the residual mean meridional circulation in the stratosphere , 1995 .

[25]  J. Wallace,et al.  On the cause of the annual cycle in tropical lower-stratospheric temperatures , 1994 .

[26]  James M. Russell,et al.  The Halogen Occultation Experiment , 1993 .

[27]  Robert E. Veiga,et al.  An overview of sage I and II ozone measurements , 1989 .

[28]  R. J. Reed,et al.  The Annual Temperature Variation in the Lower Tropical Stratosphere , 1969 .