About the Image

The NAST-I has a spatial resolution of 2.5 km and a spectral resolution of 0.25 cm^-1 over a spectral range from 3.5 to 16 microns. This graphic demonstrates, using NAST-I, that the high spatial resolution retrievals of water vapor at 800 milibars at half-hourly intervals from GIFTS will provide observations of water vapor flux and wind profile information. In this case, an animated set of half-hourly interval images of water vapor (in terms of mixing ratio and relative humidity) are derived from a time series of NAST-I profile retrievals from spectral radiance observations over a small area near Andros Island, Bahamas. These animations imply that the water vapor flux can be observed. The flow is seen to change direction with altitude. These experimental results, which imply a strong vertical shear in wind direction, indicate that vertical profile information about the wind velocity can be achieved by observing the displacement of water vapor features at different atmospheric levels, a unique element of the GIFTS measurement concept proposed.