16.4
Equatorial asymmetric simulations of the ITCZ and shallow meridional circulation
David S. Nolan, University of Miami, Miami, FL; and C. Zhang and S. W. Powell
In a prior study, the WRF model was used to simulate the Hadley circulation, ITCZ, and recently discovered shallow meridional circulation (SMC) in an idealized tropical channel domain. In particular, the domain covered from the equator to 30N, with a linearly varying SST maximized at the equatorial boundary. To better understand the ITCZ and SMC, this work is now continued with larger domains that extend across the equator, allowing for meridionally asymmetric SST distributions. As the SST maximum is moved off the equator, the SMC strengthens in the direction back across the equator, and becomes nearly non-existent in the poleward direction. This effect is even greater when a meridional SST profile modeled after the observed SST in the East Pacific is used. In these cases the robust convectively coupled Kelvin wave seen in the prior simulations disappears and the ITCZ is then modulated and disrupted by sporadic TC genesis on the poleward side. .
Session 16, Tropical Circulations
Friday, 29 June 2007, 8:30 AM-10:00 AM, Ballroom South
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