COSMIC-2 radio occultation temperature, specific humidity, and precipitable water in Hurricane Dorian (2019)

Because of its high signal-to-noise ratio, at least 70% of the C2 soundings penetrate to within 1 km of the surface over the oceans, even in the extremely moist hurricane atmosphere.

We compute biases and standard deviations of differences of C2 temperature and specific humidity with respect to ERA5 and estimate the standard deviation of random errors of C2 using the three-cornered hat (3CH) method. The C2 profiles of mean temperature and specific humidity agree closely with ERA5 above 2 km, with a temperature bias of less than 0.3 K and a specific humidity bias of less than 0.3 g kg(-1) (15%). Below 2 km, C2 shows a dry bias of up to 2 g kg(-1) relative to ERA5, which is likely related to factors other than super-refraction.