Special MMM/CGD Joint Seminar - Mesoscale Eddy Momentum Flux in a 7km Mesh Global Atmosphere Model

*Special MMM/CGD Joint Seminar *Please note Special Day and Time

Title: Mesoscale Eddy Momentum Flux in a 7km Mesh Global Atmosphere Model

Presenter: Brian Mapes, University of Miami

Abstract:  A two-year global nonhydrostatic atmosphere simulation on a 7km mesh (G5NR from NASA’s GEOS-5 model) is queried for one of its most unique strengths: What is the vertical momentum flux (u’w’ and v’w') by explicit air motions in the mesoscale (7-444 km) scale range? After motivating this classic question, especially in light of the hypothesis that organized convection can act as an upscale energy transfer (via upgradient flux, a “negative viscosity”), we address it comprehensively with the data. A global climatology indicates that these mesoscale motions overall act as positive viscosity (damping the shear kinetic energy SKE), except perhaps for some grid points with steep topography. However, cases of positive SKE tendency are also seen. We drill down into full-resolution data for selected situations to expose the nature of the calculation and the phenomena involved. Cyclones in shear are especially prodigious in producing convection-momentum interactions, of both signs, through preferential sampling of non-average low-level momentum. 

*Special Day and Time: Friday, August 17, 2018, 11:30am Refreshments 11:15am FL2-1022 Large Auditorium, Live webcast http://ucarconnect.ucar.edu/live

Thursday, August 9, 2018 to Friday, August 17, 2018

Building:

Room Number: 
Main Auditorium, Room 1022

Type of event:

Will this event be webcast to the public by NCAR|UCAR?: 
Announcement Timing: 
Thursday, August 9, 2018 to Friday, August 17, 2018
Calendar Timing: 
Friday, August 17, 2018 - 11:30am to 12:30pm

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