CloudSat measurements of landfalling hurricanes Gustav and Ike (2008)

Abstract

[1] The spaceborne 94 GHz radar onboard the CloudSat polar orbiting satellite offers new opportunities in estimating parameters of precipitating cloud systems including hurricanes. CloudSat measurements can resolve the vertical extent of storms and hurricanes, thus providing a view of their complex structure. These measurements can be used to retrieve with high spatial resolution rainfall and ice content parameters in an atmospheric vertical column as the satellite moves over the precipitating systems. Two major Atlantic hurricanes of the 2008 season, Gustav and Ike, were observed by CloudSat near their landfalls on the coast of the Gulf of Mexico. CloudSat measurements indicated cloud top heights at around 14–16 km above the ground and extended areas of startiform-like precipitation with estimated rain rates in a range of about 3–12 mm h−1. The radar bright band features observed just below the freezing level were identifiable for most measured reflectivity profiles. Maximum retrieved ice water path values reached about 20,000 g m−2. CloudSat rain rate retrievals over land and water agreed reasonably well with approximately coincident estimates from surface precipitation radars in the areas where measurements from these radars were available and were not contaminated by melting layer returns. Hurricane Gustav remnants observed by CloudSat several days after the landfall were characterized by smaller values of rain rate and ice water path (∼2–3 mm h−1 and 1000–10,000 g m−2, correspondingly). The hurricane parameters retrieved from CloudSat measurements may complement data from other satellite sources, which are traditionally used for hurricane observations.