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Cooperative Institute for Meteorological Satellite Studies / University of Wisconsin-Madison
CIMSS Tropical Cyclone Team
Atmospheric Motion Vectors (AMV) - Product Description

Upper-Level Atmospheric Divergence
 
Background: Using the gridded atmospheric motion vector output u and v AMV components are averaged over the 150, 200, 250, and 300 hPa levels. Divergence is computed using finite differencing of du/dx + dv/dy, where u and v are the wind components and x and y are the horizontal grid spacing. In the plots positive divergence values are shown with solid lines, negative values (convergence) are shown with dashed lines. Units are 10-6s-1.
 
Uses: Upper-level atmospheric divergence can be used by tropical cyclone (TC) forecasters to estimate the strength of the TC secondary circulation, including the low-level inflow into the TC core, the convective updraft strength within the TC eyewall, and the resulting outflow/venting at the top of the TC. This dynamic can be important for storm growth and development. An area strong upper-level divergence can be seen in the blue box of this figure.
 
For more AMV information, please visit the International Winds Working Group (IWWG) page.
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