Combining airborne wave observations with WAVEWATCH III model output

Since 1998 the NASA Scanning Radar Altimeter (SRA) has been providing targeted observations of the directional wave spectrum in the vicinity of hurricanes from a NOAA WP-3D hurricane research aircraft. Because the directional wave spectrum is the air-sea interface, knowledge of it is important in studying the coupled marine boundary layers. One of the most important days of the CBLAST experiment was 1 September 2004 when Hurricane Frances passed over an array of in-situ sensors air-deployed in its path. Because of the long transit from Barbados, the NOAA aircraft was only able to make three eye penetrations and data from important areas near the eyewall were lost on the two whose flight lines extended into the right side of the track of Frances because of rain attenuation at the 3 km height. By combining the model output of WAVEWATCH III with the SRA observations from Frances and Hurricane Ivan on 14 September 2004, when six eye penetrations were made in that storm of similar size, strength, and forward speed, a much better picture of the wave field variation in the vicinity of Frances is determined. Comparisons such as these are important in establishing the accuracy of WAVEWATCH III in the coupled GFDL hurricane-wave-ocean model that will be transitioned to the Hurricane WRF model.