Feasibility study of ESA missions with G-band radar for ice cloud observations

This master’s thesis investigates the advantages and disadvantages of deploying a spaceborne G-Band weather radar system, with a primary focus on its potential contributions to atmospheric profiling and cloud microphysics characterization. The study proposes that G-band radar, used in conjuction with other radar systems at lower frequencies (Ka and W Bands) that have already been deployed and demonstrated in space, can offer improved microphysical retrievals of hydrometeor size, scattering properties and hydrometeor water content. G-Band operates at higher frequency than conventional cloud radars at Ka-Band, thus working mainly in the non Raileygh regime it could unlock new possibilities in profiling high altitudes ice cloud, super cooled liquid water clouds and precipitating snow. Clouds and precipitation systems significantly impact Earth’s hydrological and radiation budget and as we stand today there are no valid methods to evaluate the quantity and position of supercooled liquid water clouds, wich are an important contribution to earth radiation budget and latent heat profiles. Uncertainties in their representation contribute to the largest source of uncertainty in climate sensitivity estimates, accurate estimation of cloud properties, including particle size distribution and liquid water path (LWP), is crucial for improving weather and climate models. In this study are presented simulations of a 238 GHz radar paired with a 35GHz and a 94 GHz satellite passing over the globe in a polar orbit to survey the synergy and complementarity between the systems that could unveil regions with small water content below the actual detectable threshold thanks to a Differential Reflectivity between the frequencies. The work in this thesis is paramount for ongoing projects that are important for the quest of demonstrating the feasibility of the technology, the ESA Earthcare mission and NASA Cloud Radar System (CRS). The simulations are conducted on MatLab, radar products are taken from Afternoon train (A-train) constellation, and atmospheric properties from ECMWF. The study was conducted in collaboration with University of Leicester. Results of the sensitivity and sinergy-complementarity studies suggest that it would be beneficial to pair a G-Band radar with a Ka and W Band radar, in high latitudes regions and low latitudes at high altitudes regions it generates valuable difference in data between the systems so that it is possible to extrapolate informa- tion even in low sensitivity scenarios, whereas in low latitude regions the pair could be ineffective due to high level of water vapour absorption. Results of the super cooled liquid water cloud (SCLWC) study demonstrate that it could be possible the detection of the aforementioned clouds, depending on the Liquid water content, thanks to the multi-frequency approach, evaluating the amount of absorption in both cases and comparing the results, since G-band is more susceptible to water attenuation. This phenomena is more detectable in clear skies than in presence of clouds and precipitation, where the SCLWC could be located inside a system of clouds and precipitation