Wind Field Structure, Divergence and Vertical Exchange in PASE
Abstract
Divergence estimates have been made with the wind data from the NCAR C-130 aircraft in the equatorial area east of Christmas Island during the Pacific Atmospheric Sulfur Experiment (PASE) using the regression method of Lenschow et al. (Journal of Atmospheric and Oceanic Technology, 2007). In this approach the first order spatial and temporal gradients of the wind are estimated by a least squares fit to the aircraft observations. These divergence values will be compared with large scale divergence estimates from NCEP Global Forecast System wind fields. The GFS is a gridded, global meteorological analysis, available here at intervals of six hours at 0.5° × 0.5° resolution at increments of 25 hPa in the lowest layers where most of the flight legs were carried out. In three cases the flight tracks were circles and in the remaining flights the tracks were a V-pattern with an interior angle of about 60° with the centerline approximately aligned with the mean wind. Contrasting the results in these cases may be informative. We will discuss the implications of boundary layer structure tendencies for short lived and longer-lived substances such as those observed in PASE. The comparison with the GFS data has implications for the adequacy of the large-scale wind field for long range trajectory calculations, and this will be discussed as well.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2008
- Bibcode:
- 2008AGUFM.A51D0126M
- Keywords:
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- 0368 Troposphere: constituent transport and chemistry;
- 3307 Boundary layer processes;
- 3374 Tropical meteorology