Stratosphere Troposphere Exchange Trajectories analyses for the campaign
- Slides: 12
Stratosphere – Troposphere Exchange: Trajectories analyses for the campaign of November 2003 O. Cuevas*, M. Rojas** and R. Alcafuz*** *Universidad de Valparaíso, Centro de Modelamiento Matematico Universidad de Chile ** Departamento de Geofísica, Universidad de Chile *** Dirección Meteorológica de Chile
We want to assess the origin/destiny of the air masses affecting Rapanui (27º S, 109ºW, 51 m. a. s. l. ) and Tololo (30ºS, 70ºW, 2220 m. a. s. l. ) to interpret the soundings performed at theses sites during the campaign of November 2003. For that purpose, we use 3 -D meteorological fields to calculate forward an backward trajectories for Rapanui and Tololo.
MM 5 Set up Trajectories over Rapanui Trajectories over Tololo The Penn State-NCAR fifth generation Mesoescale Model (MM 5), fed with reanalisys field as IC and BC has been used. In this simulations the upper boundary was lifted up to 30 h. Pa in order to include the tropopause region.
Synoptic Conditions and O 3 “Events” at Tololo 250 Hpa 500 Hpa
Synoptic conditions, STJ (m/s), 250 h. Pa D 08 D 11 D 09 D 12 D 10 D 13
Method Backward (Forward) trajectories were calculated for 48 hours periods starting on November 15 (November 7) 2003. The calculation of trajectories was made with RIP (Read/Interpolate/Plot) RIP is a Fortran program that invokes NCAR Graphics routines for the purpose of visualizing output from gridded meteorological field (MM 5). �
Results Latitud e Latitude Trajectories for Tololo Trajectories for Rapanui Longitude
Rapanui Backward Rapanui Forward Tololo Backward Tololo Forward
Rapanui, trajectories for November 9 and 12 Latitude Backward Longitude Forward
Tololo, trajectories for November 9 and 12 Latitude Backward Longitude Forward
Conclusions TOLOLO ●At this site, the deflection of the upper westerlies by the Andes and the subsidence induced by the subtropical high are and the predominant features. Thus, the air collected at Tololo typically arrives from the NW, originating at 4 -5 km height. ●In connection with the deep trough that approched the area by November 12, air masses originating in the marine boundary layer (MBL) to the SW of the site could be distinguished. RAPANUI The air collected at this site typically originates in the MBL west of Rapanui.