An ERS-1 synthetic aperture radar image of a tropical squall line comparedwith weather radar data

A radar image acquired by the C-band synthetic aperture radar (SAR) aboard the European Remote Sensing satellite ERS-2 over the coastal waters south o f Singapore shoeing radar signatures of a strong tropical squall line ("Sum atra Squall") is compared with coincident and collocated weather radar data . Squall line features such as the gust front, areas of updraft convergence , and rain areas are identified. Possible attenuation effects from the rain drops in the atmosphere under very heavy rain (rain rate > 100 mm/h) is su ggested, In addition, the possibility of extracting the associated geophysi cal parameters, i.e., rain rate and wind speed from SAR imagery is investig ated, The rain rate is estimated from the attenuation signature in the SAR image. Comparison between the estimated rain rate and weather radar rain ra te shows consistency. Wind speed associated with the squall line is estimat ed based on the CMOD4 wind scatterometer model. The estimated wind speed pa ttern appears to be in agreement with the observed squall line structure. P ossible errors in the wind estimation due to effects of rain are suggested.