scholarly journals The effect of potential vorticity fluxes on the circulation of the tropical upper troposphere

2018 ◽  
Vol 144 (712) ◽  
pp. 848-860 ◽  
Author(s):  
Sebastián Ortega ◽  
Peter J. Webster ◽  
Violeta Toma ◽  
Hai-Ru Chang
Keyword(s):  
Potential Vorticity ◽  
Upper Troposphere ◽  
Tropical Upper Troposphere

scholarly journals Saharan dust, convective lofting, aerosol enhancement zones, and potential impacts on ice nucleation in the tropical upper troposphere

2017 ◽  
Vol 122 (16) ◽  
pp. 8833-8851 ◽  
Author(s):  
C. H. Twohy ◽  
B. E. Anderson ◽  
R. A. Ferrare ◽  
K. E. Sauter ◽  
T. S. L'Ecuyer ◽  
...  
Keyword(s):  
Ice Nucleation ◽  
Saharan Dust ◽  
Upper Troposphere ◽  
Tropical Upper Troposphere

Reexamining the warming in the tropical upper troposphere: Models versus radiosonde observations

2012 ◽  
Vol 39 (22) ◽  
pp. n/a-n/a ◽  
Author(s):  
Dian J. Seidel ◽  
Melissa Free ◽  
James S. Wang
Keyword(s):  
Upper Troposphere ◽  
Tropical Upper Troposphere

scholarly journals Modeling the transport of very short-lived substances into the tropical upper troposphere and lower stratosphere

2009 ◽  
Vol 9 (5) ◽  
pp. 18511-18543 ◽  
Author(s):  
J. Aschmann ◽  
B. M. Sinnhuber ◽  
E. L. Atlas ◽  
S. M. Schauffler
Keyword(s):  
Large Scale ◽  
Lower Stratosphere ◽  
Transport Model ◽  
Three Dimensional ◽  
Chemical Transport Model ◽  
Heating Rates ◽  
Model Calculations ◽  
Upper Troposphere ◽  
Mass Fluxes ◽  
Tropical Upper Troposphere

Abstract. The transport of very short-lived substances into the tropical upper troposphere and lower stratosphere is investigated by a three-dimensional chemical transport model using archived convective updraft mass fluxes (or detrainment rates) from the European Centre for Medium-Range Weather Forecast's ERA-Interim reanalysis. Large-scale vertical velocities are calculated from diabatic heating rates. With this approach we explicitly model the large scale subsidence in the tropical troposphere with convection taking place in fast and isolated updraft events. The model calculations agree generally well with observations of bromoform and methyl iodide from aircraft campaigns and with ozone and water vapor from sonde and satellite observations. Using a simplified treatment of dehydration and bromine product gas washout we give a range of 1.6 to 3 ppt for the contribution of bromoform to stratospheric bromine, assuming a uniform source in the boundary layer of 1 ppt. We show that the most effective region for VSLS transport into the stratosphere is the West Pacific, accounting for about 55% of the bromine from bromoform transported into the stratosphere under the supposition of a uniformly distributed source.

scholarly journals A statistical analysis of the influence of deep convection on water vapor variability in the tropical upper troposphere

2009 ◽  
Vol 9 (15) ◽  
pp. 5847-5864 ◽  
Author(s):  
J. S. Wright ◽  
R. Fu ◽  
A. J. Heymsfield
Keyword(s):  
Water Vapor ◽  
Deep Convection ◽  
Tropical Rainfall Measuring Mission ◽  
Upper Troposphere ◽  
Ambient Relative Humidity ◽  
Wide Range ◽  
Ice Water Content ◽  
The Tropics ◽  
Ice Water ◽  
Tropical Upper Troposphere

Abstract. The factors that control the influence of deep convective detrainment on water vapor in the tropical upper troposphere are examined using observations from multiple satellites in conjunction with a trajectory model. Deep convection is confirmed to act primarily as a moisture source to the upper troposphere, modulated by the ambient relative humidity (RH). Convective detrainment provides strong moistening at low RH and offsets drying due to subsidence across a wide range of RH. Strong day-to-day moistening and drying takes place most frequently in relatively dry transition zones, where between 0.01% and 0.1% of Tropical Rainfall Measuring Mission Precipitation Radar observations indicate active convection. Many of these strong moistening events in the tropics can be directly attributed to detrainment from recent tropical convection, while others in the subtropics appear to be related to stratosphere-troposphere exchange. The temporal and spatial limits of the convective source are estimated to be about 36–48 h and 600–1500 km, respectively, consistent with the lifetimes of detrainment cirrus clouds. Larger amounts of detrained ice are associated with enhanced upper tropospheric moistening in both absolute and relative terms. In particular, an increase in ice water content of approximately 400% corresponds to a 10–90% increase in the likelihood of moistening and a 30–50% increase in the magnitude of moistening.

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