Location
East-West Center, University of Hawai'i at Manoa (Honolulu, Hawai'i)
Start Date
16-10-2012 5:30 PM
End Date
16-10-2012 7:30 PM
Document Type
Poster
Description
Tropical upwelling should exert strong influence on temperatures and on tracers with large vertical gradients in the lower stratosphere. We test this behavior by comparing three upwelling estimates calculated from ERA‐Interim reanalysis data with observed temperatures in the tropical lower stratosphere, and with measurements of ozone and carbon monoxide (CO) from the Aura Microwave Limb Sounder (MLS) satellite instrument. Time series of temperature, ozone and CO are well correlated in the tropical lower stratosphere, and we quantify the influence of tropical upwelling on this joint variability. Strong coherent annual cycles observed in each quantity are found to reflect the seasonal cycle in upwelling. Other contributions to the zonal mean tracer budgets are chemical production and loss and eddy mixing. We use data from the Whole Atmosphere Community Climate Model (WACCM) to investigate the seasonality and spatial structure of the different terms in the balances. Tropical upwelling, temperatures and tracers are significantly correlated also when isolating subseasonal timescales. This demonstrates the importance of upwelling in forcing transient variability in the lower tropical stratosphere.
Correlated variability of upwelling and tracers near the tropical tropopause
East-West Center, University of Hawai'i at Manoa (Honolulu, Hawai'i)
Tropical upwelling should exert strong influence on temperatures and on tracers with large vertical gradients in the lower stratosphere. We test this behavior by comparing three upwelling estimates calculated from ERA‐Interim reanalysis data with observed temperatures in the tropical lower stratosphere, and with measurements of ozone and carbon monoxide (CO) from the Aura Microwave Limb Sounder (MLS) satellite instrument. Time series of temperature, ozone and CO are well correlated in the tropical lower stratosphere, and we quantify the influence of tropical upwelling on this joint variability. Strong coherent annual cycles observed in each quantity are found to reflect the seasonal cycle in upwelling. Other contributions to the zonal mean tracer budgets are chemical production and loss and eddy mixing. We use data from the Whole Atmosphere Community Climate Model (WACCM) to investigate the seasonality and spatial structure of the different terms in the balances. Tropical upwelling, temperatures and tracers are significantly correlated also when isolating subseasonal timescales. This demonstrates the importance of upwelling in forcing transient variability in the lower tropical stratosphere.
