Vertical structure, physical properties, and energy exchange of the East Asian trough in boreal winter

The relation between the intensity of the East Asian trough and the strength of the East Asian winter monsoon is documented. A prominent dipole of the available potential energy of the zonal mean flow can be observed over the midlatitudes and polar regions and is related to temperature anomalies. Variation in the intensity of the East Asian trough is caused by variation in the energy conversion from the available potential energy of the zonal mean flow to the East Asian trough. The in-phase relation between the intensities of the East Asian jet and East Asian trough is illustrated by the relation between the potential energy and kinetic energy of stationary eddies. The dipole of height anomalies over the midlatitude and polar regions develops in late autumn and decays in early spring. We investigate the effect of both stationary and transient eddy forcing on the evolution of the dipole. The combined forcing of the two types of eddy makes an important contribution to the development, maintenance, and decay of the dipole.