Precipitation in the Arctic and Southern Ocean: new insights from aircraft and ship-borne measurements

Precipitation is an important component of the hydrologic cycle and sea ice mass balance in polar regions. However, precipitation products in high latitudes constitute the highest uncertainties among satellite retrievals and numerical models. These uncertainties arise from limited in-situ observations of high-latitude precipitation and the fundamental differences between the Arctic and Southern Ocean/Antarctic environments that complicate the key precipitation properties and associated processes. To help address this knowledge gap, this study uses recent aircraft and ship-borne measurements to understand better the microphysical properties of precipitation over the Arctic and Southern Ocean/Antarctic regions. For the Arctic case, select summertime precipitation events are examined using aircraft measurements from precipitation imaging probes. We present the microphysical properties of Arctic precipitation in terms of the dominant ice precipitation type, particle size distributions, and important bulk properties. For the Southern Ocean/Antarctic case, we use recent measurements from ship-borne disdrometer and dual-polarimetric radar and present the distinctive polarimetric signatures and surface precipitation properties of seven synoptic types across the Southern Ocean. We also demonstrate an improved radar rainfall retrieval algorithm for the region, considering the dominance of small raindrop sizes of less than one millimeter in Southern Ocean rainfall. This research is leading toward more accurate, high-resolution estimates of precipitation properties in high-latitude regions, crucial in advancing the understanding of a range of climatological and meteorological processes as well as in evaluations of weather and climate models.