The feasibility of conducting a dual-Doppler analysis when the radar baseline is larger than normal is examined. It was found that carefully editing and analyzing the data can enable the recovery of the low-resolution flow field. Although errors associated with this method are larger than those associated with a typical ground-based dual-Doppler analysis, they are not so large that its meteorological usefulness for recovering the low-resolution flow fields becomes compromised. This long baseline dual-Doppler analysis technique is tested on a mesoscale convective system (MCS) observed by the TOGA COARE ship-borne Doppler radars over a 60-minute period.

The accuracy of the long-baseline technique is tested in several ways. First, the recovered low-resolution kinematic fields are compared with data obtained for the same MCS from other observational platforms. Then, observed structures and morphologies of similar MCSs during TOGA COARE will be subjectively compared to those recovered using the long-baseline technique. Further, the evolution of this MCS is examined for continuity of the observed structures over a 60-minute period. Using the low-resolution flow field, the area-averaged divergence profiles of various regions within the MSC are computed. The low-resolution flow fields and area-averaged divergence profiles derived from this method show a zone of enhanced convergence along the southern edge of the convective band. This results in a slight (25∞) counter-clockwise rotation of the convective band. This finding is consistent with the results from other observational studies of this particular MCS.