Environmental & Climate Sciences Department Seminar

Cloud microphysical processes, such as droplet activation, condensational, and collisional growth, play a crucial role in the evolution of clouds and precipitation. Accurate representations of these processes in numerical models, which are essential to weather and climate models predictions, are challenging partially due to incomplete understanding of those processes at the process level arising from limited observations. Specifically, typical cloud radars have a resolution on the order of tens of meters. This resolution is insufficient to resolve critical microphysical processes that manifest at finer scales (meter and sub-meter). To mitigate this observational gap, we introduce two novel radar systems with high range resolution capability: 1) The first system is a W-band (94GHz) radar with a range resolution down to 3 m, which is a factor of 10 finer than the typical cloud radar. The first-light cloud observations reveal detailed cloud structures that conventional sensors could only perceive in a bulk sense, providing new avenues to investigate cloud microphysical processes and their impact on climate system. 2) The second instrument is a THz (680 GHz) radar system operating with a centimeter scale resolution. An experiment is conducted by applying the THz radar to measure the hydrometeors generated in a spray chamber and observations show fine-scale particle distribution patterns. Finally, the potential application of the THz radar for drizzle detection in a cloud chamber facility is discussed. The high-resolution capability allows the THz radar to detect a single particle with a diameter around 50 micrometers. The theoretical foundation of this particle detection concept is discussed followed by a validation from the Pi Cloud Chamber observation.