Kinematic characteristics of air flowing into and out of precipitating convection over the west Pacific warm pool: An airborne Doppler radar survey

Air flowing into and out of 25 cloud systems over the west Pacific warm pool was sampled by Doppler radars on board two NOAA WP-3D aircraft and the NCAR Electra aircraft during the Tropical Ocean/Global Atmosphere Coupled Ocean-Atmosphere Response Experiment (TOGA-COARE). In convective cells, updraught inflows and downdraught outflows tended to be positioned adjacent to each other at sharp updraught-downdraught interfaces sloping at various angles and directions. The updraught inflows were sometimes shallow and sometimes deep, often extending well above the boundary layer. Downdraught outflow magnitudes were usually stronger than updraught inflows, and the horizontal directions of the inflow and outflow were frequently offset from each other at angles of similar to\90 degrees\. In stratiform precipitation regions, the dominant airflow features were descending mid-level inflows, located at the bases of anvils and often extending into the interior of the precipitation system. These stratiform inflows originated at levels between 5 and 10 km and descended to about 3 km. A few extended down to the surface. Stratiform inflows were typically strong and sandwiched between weaker stratiform outflows at upper and lower altitudes. The stratiform-region inflow and outflow directions were frequently offset by similar to\90 degrees\ in the horizontal. The mid-level inflow currents entered the stratiform regions horizontally from a direction similar to that of the large-scale ambient wind. The mid-level stratiform inflow tended to occur in the same vertical plane as the convective downdraught outflow, although the mid-level stratiform inflow appeared to be slowed by horizontal pressure gradients before connecting with the convective downdraught outflow. In other respects, the mesoscale systems differed from a simplified two-dimensional model of airflow. The systems moved primarily by discrete propagation, and updraughts and downdraughts tended to have orthogonal horizontal relative airflow.