65th IHC Booklet/Program (pdf - 4.9MB) - Office of the Federal ...

An Overview of COAMPS-TC Development and Real-Time Tests
James D. Doyle, R. Hodur, S. Chen, J. Cummings, E. Hendricks, T. Holt, H. Jin, Y. Jin, C.-S.
Liou, J. Moskaitis, M. Peng, K. Sashegyi, J. Schmidt, S. Wang
(James.Doyle@nrlmry.navy.mil)
Naval Research Laboratory
The newly developed Coupled Ocean/Atmosphere Mesoscale Prediction System – Tropical
Cyclone (COAMPS ® -TC), designed to predict tropical cyclone track, structure, and intensity, has
been applied in real-time in support of the recent Hurricane Forecast Improvement Project
(HFIP). These real time forecasts were performed in the Atlantic basin; and in the Eastern,
Central, and Western Pacific basins during the 2009 and 2010 seasons. Additionally,
retrospective tests for HFIP were conducted on a large sample of storms (more than 400 cases)
over the W. Atlantic and E. Pacific basins for hurricanes that occurred in the 2008 and 2009
seasons. For these real time and retrospective tests, the COAMPS-TC system was configured
with three nested grids, with 45, 15, 5 km horizontal grid spacings. The inner two meshes
automatically moved with the tropical cyclone center.
A number of improvements were made to the COAMPS-TC physics and data assimilation based
on the results of the 2009 tropical cyclone forecast season. This version of COAMPS-TC was
then evaluated using the HFIP retrospective cases performed for 2008 and 2009. The intensity
forecasts for the retrospective tests show the model skill for intensity was superior to other
dynamical models, particularly for the 30-72 h forecast range. Similarly, an analysis of the 2010
real-time forecasts in support of HFIP reveals that the COAMPS-TC intensity forecasts for the
W. Atlantic were superior to other dynamical models for the 30-66 h forecast range. Statistical
verification from these retrospective tests indicates that the COAMPS-TC system provided
skillful track forecasts competitive with other limited area models such as the Navy’s GFDN.
Following the analysis of the 2010 real time forecast results, a number of improvements were
made to COAMPS-TC including a new algorithm for synthetic observations, inclusion of
additional observations such as satellite derived total precipitable water that are used by the Navy
Atmospheric Variational Data Assimilation System (NAVDAS), and a new formulation of
vertical mixing within clouds and deep convection. Sensitivity test results from this new
improved version of COAMPS-TC will be presented. Additionally, real-time application of
COAMPS-TC in the W. Pacific basin during the Interaction of Typhoons and Ocean Processes
(ITOP) will be discussed.
Session 5 – Page 5