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An experiment in numerical prediction in equatorial latitudes
Author(s) -
Krishnamurti T. N.
Publication year - 1969
Publication title -
quarterly journal of the royal meteorological society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.744
H-Index - 143
eISSN - 1477-870X
pISSN - 0035-9009
DOI - 10.1002/qj.49709540511
Subject(s) - intertropical convergence zone , geology , convection , tropical cyclone , convergence (economics) , climatology , potential temperature , convergence zone , meteorology , geodesy , atmospheric sciences , physics , precipitation , economic growth , economics
A short‐range prediction experiment is performed to study the dynamical structure of the tropical atmosphere in equatorial latitudes. The initial field includes the intertropical convergence zone and associated disturbances over the western Pacific Ocean during March 1965. A complete initial state is constructed using a consistent balanced system of equations. The procedure involves construction of pressure, temperature and vertical motion distributions starting from the rotational part of the observed wind field. It is shown that this procedure, the validity of which assumes a small Rossby number, does not yield a realistic field of vertical motion. A short‐range prediction with a multi‐level prediction model yields some interesting solutions in the vicinity of the intertropical convergence zone. During the first 18 hours of prediction there occurs an adjustment of the motion and the mass field, with gravity‐inertia oscillations. An important feature of the model is a parameterization of cumulus convection as a function of the largescale moisture convergence. The role of cumulus scale heating in the vicinity of the intertropical convergence zone is investigated and it is shown that during the adjustment process a convergence zone forms which exhibits a strong coupling with the zone of frictional vertical rising motion and the field of computed cloud cover. The formation of this feature appears to represent the numerical simulation of a tropical storm.