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Aircraft observations made off the coast of northern Chile in the Southeastern Pacific (20 degrees S, 72 degrees W; named Point Alpha) from 16 October to 13 November 2008 during the VAMOS Ocean-Cloud-Atmosphere-Land Study-Regional Experiment (VOCALS-REx), combined with meteorological reanalysis, satellite measurements, and radiosonde data, are used to investigate the boundary layer (BL) and aerosol-cloud-drizzle variations in this region. On days without predominately synoptic and meso-scale influences, the BL at Point Alpha was typical of a non-drizzling stratocumulus-topped BL. Entrainment rates calculated from the near cloud-top fluxes and turbulence in the BL at Point Alpha appeared to be weaker than those in the BL over the open ocean west of Point Alpha and the BL near the coast of the northeast Pacific. The cloud liquid water path (LWP) varied between 15 gm(-2) and 160 gm(-2). The BL had a depth of 1140 +/- 120 m, was generally well-mixed and capped by a sharp inversion without predominately synoptic and mesoscale influences. The wind direction generally switched from southerly within the BL to northerly above the inversion. On days when a synoptic system and related mesoscale costal circulations affected conditions at Point Alpha (29 October-4 November), a moist layer above the inversion moved over Point Alpha, and the total-water mixing ratio above the inversion was larger than that within the BL. The accumulation mode aerosol varied from 250 to 700 cm(-3) within the BL, and CCN at 0.2% supersaturation within the BL ranged between 150 and 550 cm(-3). The main aerosol source at Point Alpha was horizontal advection within the BL from south. The average cloud droplet number concentration ranged between 80 and 400 cm(-3). While the mean LWP retrieved from GOES was in good agreement with the in situ measurements, the GOES-derived cloud droplet effective radius tended to be larger than that from the aircraft in situ observations near cloud top. The aerosol and cl

Aircraft observations made off the coast of northern Chile in the Southeastern Pacific (20 degrees S, 72 degrees W; named Point Alpha) from 16 October to 13 November 2008 during the VAMOS Ocean-Cloud-Atmosphere-Land Study-Regional Experiment (VOCALS-REx), combined with meteorological reanalysis, satellite measurements, and radiosonde data, are used to investigate the boundary layer (BL) and aerosol-cloud-drizzle variations in this region. On days without predominately synoptic and meso-scale influences, the BL at Point Alpha was typical of a non-drizzling stratocumulus-topped BL. Entrainment rates calculated from the near cloud-top fluxes and turbulence in the BL at Point Alpha appeared to be weaker than those in the BL over the open ocean west of Point Alpha and the BL near the coast of the northeast Pacific. The cloud liquid water path (LWP) varied between 15 gm(-2) and 160 gm(-2). The BL had a depth of 1140 +/- 120 m, was generally well-mixed and capped by a sharp inversion without predominately synoptic and mesoscale influences. The wind direction generally switched from southerly within the BL to northerly above the inversion. On days when a synoptic system and related mesoscale costal circulations affected conditions at Point Alpha (29 October-4 November), a moist layer above the inversion moved over Point Alpha, and the total-water mixing ratio above the inversion was larger than that within the BL. The accumulation mode aerosol varied from 250 to 700 cm(-3) within the BL, and CCN at 0.2% supersaturation within the BL ranged between 150 and 550 cm(-3). The main aerosol source at Point Alpha was horizontal advection within the BL from south. The average cloud droplet number concentration ranged between 80 and 400 cm(-3). While the mean LWP retrieved from GOES was in good agreement with the in situ measurements, the GOES-derived cloud droplet effective radius tended to be larger than that from the aircraft in situ observations near cloud top. The aerosol and cl

A real-time forecast method is developed for prediction of the tropical cyclogenesis location over the Atlantic using global model operational products. The method is based on the marsupial theory for tropical cyclogenesis proposed in a recent observational study. A moisture front is usually found ahead of the precursor wave trough, which separates the relatively dry air outside of the wave pouch (a region of closed circulation) from the relatively moist air inside the wave pouch. The propagation speed of the pouch can be determined by tracking the propagation of this moisture front, and the intersection of the critical surface and the trough axis pinpoints the predicted genesis location. Using the global model operational products the genesis location can be predicted up to three days in advance with an error less than 200 km, which can provide useful guidance for forecasters and flight planning., Published in Geophysical Research Letters, v36 L03801, 2009. Sponsored in part by NASA.

This is a report of the proceedings of a workshop on chemical kinetic data needs for modeling the lower troposphere, held at Reston, Virginia, May 15-17, 1978. The meeting, sponsored by the Environmental Protection Agency and the National Bureau of Standards, focussed on six key problem areas in tropospheric chemistry: reactions of olefins with hydroxyl radicals and ozone, reactions of aldehydes, free radical reactions, reactions of oxides of nitrogen, reactions of aromatic compounds, and reactions of oxides of sulfur.