![Sample our Environment & Agriculture journals, sign in here to start your access, latest two full volumes FREE to you for 14 days]({"type":"image" , "src" : "/sda/5934/TOC-Subject-Sample-2021-Environment-Agriculture.jpg"})
Abstract
The multi-year outgoing long-wave radiation (OLR) and velocity potential (χ) generated from the 200-mb wind fields of the National Meteorological Center and the European Centre for Medium-Range Weather Forecasts were used to examine the structure of the semi-annual divergent circulation and its relation with tropical cumulus convection. As inferred from the semi-annual mode of the asymmetric OLR component (OLRE), the east’west differential response to the solar heating between the Asian-Australian (AA) monsoon (60°E–120°W) and the extra-AA monsoon (120°W–60°E) hemispheres sustains a distinct semi-annual mode of the asymmetric divergent circulation with a wavenumber-1 structure. This semi-annual mode of the asymmetric divergent circulation, represented by the asymmetric velocity potential (χE), develops in time coherently with the semi-annual mode of tropical cumulus convection, which indicates a faster response in the extra-AA monsoon hemisphere. That is, the negative centres of semiannual OLRE anomalies and the divergent center of the semi-annual χE field appear in the extra-AA monsoon hemisphere in April/October and in the AA-monsoon hemisphere in January/July.