Rennie Selkirk, NASA-Ames/BAER Institute Holger Vömel, University of Colorado Leonhard Pfister, NASA-Ames Jessica Valverde, Universidad Nacional Werner Stolz, Insituto Meteorológico Nacional Walter Fernández and Jorge Andrés Diaz, Universidad de Costa Rica Jimena Lopez, NASA-Ames/BAER Insitute Forecasting tropopause temperatures over Costa Rica for TC 4 BACKGROUND Supplementary material for NASA TC4 Science Team meeting, Lanham-Seabrook, MD, April 2007 Vertically propagating equatorial waves, probably mixed Rossby-gravity waves, have been observed in the lower stratosphere and TTL during each of the 3 summer Ticosonde campaigns since Most prominent contribution to the variability of tropopause temperature at timescales of several days or more Temperature variations are NOT directly forced by convection Twice in 2005, wave-induced cooling was sufficient to dehydrate the tropopause to mixing ratios of 3 ppmv and lower (CFH dehydration events on July 11 and 19.) Tropopause temperature anomaly amplitudes appear to be sensitive to the phase of the QBO: the strong easterly phase in 2005 ‘bottled up’ wave energy at the tropopause, inducing larger variance than in the weak easterlies in 2004.

Significance for TC 4 Supplementary material for NASA TC4 Science Team meeting, Lanham-Seabrook, MD, April 2007 Tropopause temperatures during TC 4 will exhibit regular variations on the 3-4 day timescale w/ amplitude of ~5 °C Widespread cirrus more likely during wave-induced cold events If strong easterly phase of QBO (like 2005), expect increased amplitude of tropopause temperature anomalies and possible dehydration events Forecasting T trop during TC 4 Ticosonde will provide continual updates of time-height diagrams of temperature and wind using both the sondes and analysis/forecast datasets

Vaisala RS92-SGP radiosondes –4X daily: 16 July – 24 August –typically ascents to ~28 km –2-sec 10 m CU CFH and ECC ozonesondes –24 launches: 8 – 25 July 18 UT; 00 UT (night) –typical balloon burst at ~30 km Time-height cross-sections from Ticosonde-Aura/TCSP 2005 Supplementary material for NASA TC4 Science Team meeting, Lanham-Seabrook, MD, April 2007

Ticosonde-TCSP 2005 time-height X-section: Temperature anomalies Cold point range T July 11 Dehydration observed by CFH July 19 Dehydration observed by CFH CFH observations Supplementary material for NASA TC4 Science Team meeting, Lanham-Seabrook, MD, April 2007

Ticosonde-TCSP 2005 time-height X-section: Temperature anomalies Cold point range T Arrows = cold T anoms July 11 Dehydration observed by CFH July 19 Dehydration observed by CFH CFH observations Supplementary material for NASA TC4 Science Team meeting, Lanham-Seabrook, MD, April 2007

Ticosonde-TCSP 2005 time-height X-section: zonal wind anomalies Cold point range July 11 Dehydration observed by CFH July 19 Dehydration observed by CFH U CFH observations Supplementary material for NASA TC4 Science Team meeting, Lanham-Seabrook, MD, April 2007

Ticosonde-TCSP 2005 time-height X-section: zonal wind anomalies Cold point range U arrows = cold T anoms July 11 Dehydration observed by CFH July 19 Dehydration observed by CFH CFH observations Supplementary material for NASA TC4 Science Team meeting, Lanham-Seabrook, MD, April 2007

Ticosonde-TCSP 2005 time-height X-section: meridional wind anomalies Cold point range July 11 Dehydration observed by CFH July 19 Dehydration observed by CFH V CFH observations Supplementary material for NASA TC4 Science Team meeting, Lanham-Seabrook, MD, April 2007

Ticosonde-TCSP 2005 time-height X-section: meridional wind anoms Cold point range V July 11 Dehydration observed by CFH July 19 Dehydration observed by CFH arrows = cold T anoms CFH observations Supplementary material for NASA TC4 Science Team meeting, Lanham-Seabrook, MD, April 2007