Geophys. Res. Lett., submitted 2/06.

Observed radar reflectivity in convectively coupled Kelvin and mixed Rossby-gravity waves

Abigail Swann
Department of Earth and Planetary Sciences, University of California, Berkeley, CA

Adam H. Sobel
Department of Applied Physics and Applied Mathematics and Department of Earth and Environmental Sciences, Columbia University, New York, NY

Sandra E. Yuter
Department of Marine, Earth, and Atmospheric Sciences, North Carolina State University, Raleigh, NC

George N. Kiladis
NOAA/Earth System Research Laboratory, Boulder, CO


Propagating disturbances in the tropical atmosphere exhibiting characteristics of linear equatorial waves have been shown to be ``coupled" to convection. In some cases, a rain event at a specific location can be associated with a particular wave of sufficiently large amplitude. Rain events spanning three years at Kwajalein Atoll, Republic of the Marshall Islands, 8.72N, 167.73E, are classified by associated wave type (i.e. Kelvin or mixed Rossby-gravity (MRG)) using space-time spectral-filtered outgoing longwave radiation (OLR). Contoured frequency by altitude diagrams (CFADs) of radar for the classified dates were compared between the two groups. The Kelvin wave accumulated CFAD has a distribution shifted to lower reflectivities suggesting that Kelvin storms likely contain a larger fraction of stratiform to convective area compared to MRG storms.