Abstract
The WIVERN (WInd VElocity Radar Nephoscope) mission, currently under the
Phase-0 of the ESA Earth Explorer program, promises to provide new
insight in the coupling between winds and microphysics by globally
observing, for the first time, vertical profiles of horizontal winds in
cloudy areas. The objective of this work is to explore the potential of
the WIVERN conically scanning Doppler 94GHz radar for filling the wind
observation gap inside tropical cyclones.
To this aim,
realistic WIVERN notional observations of TCs are produced by combining
the CloudSat 94GHz radar reflectivity observations from 2007 to 2009
with ECMWF co-located winds. Despite the short wavelength of the radar
(3mm), which causes strong attenuation in presence of large amount of
liquid hydrometeors, the system can profile most of the tropical
cyclones, particularly the cloudy areas above the freezing level and the
precipitating stratiform regions.
The statistical
analysis of the results shows that, (i) because of its lower
sensitivity, a nadir pointing WIVERN would detect 80% of the clouds
(60% of winds with 3m/s accuracy) observed by CloudSat, (ii) but thanks
to its scanning capability, WIVERN would actually provide 52 times more
observations of clouds (40~times more observations of
horizontal winds) than CloudSat in TCs, (iii) this corresponds to more
than 400 (300) million observations of clouds (accurate winds) every
year. Such observations could be used in data assimilation models in
order to improve numerical weather prediction and by modellers in order
to shed light on the physical processes underpinning the evolution of
tropical cyclones.