Wc. Chao et Lt. Deng, PHASE-LAG BETWEEN DEEP CUMULUS CONVECTION AND LOW-LEVEL CONVERGENCE IN TROPICAL SYNOPTIC-SCALE SYSTEMS, Monthly weather review, 125(4), 1997, pp. 549-559
This study deals with the origin of the phase lag between deep cumulus
convection and low-level convergence in tropical synoptic-scale syste
ms, known since 1974. Several possible causes, including 1) propagatio
n of the heating field, 2) beta, 3) vertical shear of the basic flow,
and 4) vertical tilt of the heat source, are examined. The last one is
found to be the reason for the phase lag. The vertical tilt of the he
at source occurs as a result of evolution and propagation of mesoscale
convective systems within the synoptic system. During this evolution
the change of vertical heating profile results in the tilt of heating
field. Previous efforts of incorporating such phase lag in wave-CISK s
tudies are commented on.