A Wind Speed Assessment for AltiKa
Plymouth Marine Laboratory, UNITED KINGDOM
The launch of AltiKA in spring 2013 will provide the first Ka-band altimetry from space. This new instrument offers great potential by way of high pulse repetition frequency and small footprint size, but also encounters challenges due to that radar band's sensitivity to atmospheric moisture and the lack of a fully-tested geophysical model to relate sea surface roughness to wind speed. Rain's effect on the altimeter's waveforms should manifest itself through sharp spatial changes in the inferred values for sigma0, wave height and sea surface height. Effects may also be expected in more esoteric parameters such as peakiness and waveform-derived mispointing.
This presentation will provide an early analysis of the altimeter and radiometer data to determine the data record's susceptibility to atmospheric attenuation by moisture and the applicability of techniques for flagging suspect data. Using such quality-controlled data, a vicarious calibration will be made for wind speed. This will then be used to determine spatial scales of variability and assess whether the higher resolution data available from AltiKa will provide a new insight into the spatial structure of the wind field.