Characteristics of Precipitation across the Atlantic Inter-Tropical Convergence Zone from Shipborne Sea-Pol Radar Observations during ORCESTRA

The governing mechanisms of mesoscale convective organization and precipitation across the inter-tropical convergence zone (ITCZ) are an open area of research, due in part to the lack of detailed observations over the tropical oceans. The Process Investigation of Clouds and Convective Organization over the atLantic Ocean (PICCOLO), a sub-campaign of Organized Convection and EarthCARE Studies over the Tropical Atlantic (ORCESTRA), deployed the Colorado State University Sea-Going Polarimetric (Sea-Pol) radar on the German R/V Meteor during August and September of 2024, to bridge this gap. This is the first ship-stabilized polarimetric radar deployment in this region to our knowledge. In this study we use 3D 120 km range Sea-Pol radar retrievals to analyze the spatial structure, rate, and microphysical characteristics of precipitation across the Atlantic ITCZ. We perform calculations of the height of the 10 dBZ echo and find three convection groups based on a trimodal division of frequency: shallow (1- 4 km), congestus (5- 7 km), and deep (8 km+). Results show echoes in the congestus group contributing the most to the total rain accumulation across the campaign. These congestus echoes are frequently obscured on satellite brightness temperatures by higher clouds. Deep convective echoes were found to be more infrequent but have higher rain rates per fractional area. Higher populations of deep and congestus clouds are often found in proximity, while the remaining cloud population of shallow convection is found to be more distinct spatially. The interdependence of these convective populations in the context of the ITCZ and African Easterly Wave passages, will be discussed.