On the Maintenance of the Mean Monsoon Trough Over North India

The different terms in the equation for the balance of standing eddy kinetic energy are estimated in the region of the monsoon trough over north India. The main contribution to the maintenance of the trough against frictional dissipation is from the work done by the horizontal pressure forces. The contribution by the mean and transient advection terms is of a smaller order of magnitude. There is loss of standing eddy kinetic energy by the rising of cold air and sinking of warm air in the x-p plane in the lower troposphere. The circulation is forced by the flux of pot.entia1 energy from outside, mainly from the bottom and southern boundaries. 1.