Shipboard Operations of the NASA-TOGA Radar in DYNAMO

During the DYNAMO (Dynamics of the MJO) field project, the NASA TOGA C-band Doppler radar was operated on board the R/V Roger Revelle from Scripps Institute of Oceanography. At the time of this writing, the first two DYNAMO cruises have been successfully completed. During cruise 1, the radar operation was fully checked out and made ready for the main data collection cruises that followed. During cruise 2 from late September through October 2011, the R/V Revelle maintained a fixed position along the equator at 80E longitude. In addition to the TOGA radar observations on the Revelle, atmospheric soundings, 915 MHz profiler, lidar and W-band vertically pointing radar observations were also obtained. Of course a full suite of oceanographic observations were also measured by the Revelle.

The radar is being used to study the organization and intensity of convective systems over the course of a MJO lifecycle. The second cruise documented the onset of a well-defined MJO that occurred during late October. During the period from 1-15 October, mostly isolated convective cells were observed, which drifted towards the east owing to westerly flow in the low to mid-troposphere. During the last two weeks of October, more organized mesoscale convection was frequently observed, which propagated east to west, associated with mid-to-upper tropospheric easterlies. Widespread and continuous MCS activity was especially present between 27-29 October associated with MJO onset. On 28 October, over 7 inches of rain were recorded by the Revelle's various rain gauges. The convection during cruise 2 as well as the subsequent cruises will be described in detail. The convective characteristics will be placed in the context of wind shear and moisture stratification.