Geomorphology of the Tafilalt Basin, South-East Morocco – implications for fluvial–aeolian dynamics and wind regimes

AbstractStorms crossing complex terrain can potentially encounter rapidly changing convective environments. However, our understanding of terrain-induced variability in convective stormenvironments remains limited. HRRR data are used to create climatologies of popular convective storm forecasting parameters for different wind regimes. Self-organizing maps (SOMs) are used to generate six different low-level wind regimes, characterized by different wind directions, for which popular instability and vertical wind shear parameters are averaged. The climatologies show that both instability and vertical wind shear are highly variable in regions of complex terrain, and that the spatial distributions of perturbations relative to the terrain are dependent on the low-level wind direction. Idealized simulations are used to investigate the origins of some of the perturbations seen in the SOM climatologies. The idealized simulations replicate many of the features in the SOM climatologies, which facilitates analysis of their dynamical origins. Terrain influences are greatest when winds are approximately perpendicular to the terrain. In such cases, a standing wave can develop in the lee, leading to an increase in low-level wind speed and a reduction in vertical wind shear with the valley lee of the plateau. Additionally, CAPE tends to be decreased and LCL heights are increased in the lee of the terrain where relative humidity within the boundary layer is locally decreased.

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Comment to manuscript acp-2019-26 "Cloud macro-physical properties in Saharan dust laden and dust free North Atlantic trade wind regimes: A lidar study" by Manuel Gutleben, Silke Groß, and Martin Wirth

10.5194/acp-2019-26-rc1 ◽

2019 ◽

Author(s):

Anonymous

Keyword(s):

Physical Properties ◽

North Atlantic ◽

Saharan Dust ◽

Trade Wind ◽

Atlantic Trade ◽

Wind Regimes

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Microphysical evidence of the transition between predominant convective/stratiform rainfall associated with the intraseasonal oscillation in the Southwest Amazon

Acta Amazonica ◽

10.1590/s0044-59672005000200007 ◽

2005 ◽

Vol 35 (2) ◽

pp. 175-184 ◽

Cited By ~ 4

Author(s):

Rachel Ifanger Albrecht ◽

Maria Assunção Faus da Silva Dias

Keyword(s):

Intraseasonal Oscillation ◽

Convective Precipitation ◽

Wind Regime ◽

Tropical Regions ◽

Stratiform Precipitation ◽

Type Size ◽

Global Atmospheric Circulation ◽

Microphysical Processes ◽

Wind Regimes ◽

Precipitation Formation

The distinction between convective and stratiform precipitation profiles around various precipitating systems existent in tropical regions is very important to the global atmospheric circulation, which is extremely sensitive to vertical latent heat distribution. In South America, the convective activity responds to the Intraseasonal Oscillation (IOS). This paper analyzes a disdrometer and a radar profiler data, installed in the Ji-Paraná airport, RO, Brazil, for the field experiment WETAMC/LBA & TRMM/LBA, during January and February of 1999. The microphysical analysis of wind regimes associated with IOS showed a large difference in type, size and microphysical processes of hydrometeor growth in each wind regime: easterly regimes had more turbulence and consequently convective precipitation formation, and westerly regimes had a more stratiform precipitation formation.

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