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

Lower-Level Atmospheric Convergence
Background: Using the gridded atmospheric motion vector output u and v AMV components are averaged over the 850 and 925 hPa levels. Convergence 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 convergence values are shown with solid lines, negative values (divergence) are shown with dashed lines.
Uses: Lower-level atmospheric convergence analysis can be used by tropical cyclone (TC) forecasters to identify potential areas where TC development may occur. Since the development of the TC secondary circulation (low-level inflow, updrafts in the TC eyewall, and upper-level outflow) is essential in the maturation and sustainment of a TC, identification of regions where strong TC convergent inflow near the surface can pinpoint those regions which are in favorable environments. An area of convergence 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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