Ground- and ship-based microwave radiometer measurements during EUREC4A

Abstract. During the EUREC⁴A field study, microwave radiometric measurements were performed at Barbados Cloud Observatory (BCO) and aboard the RV Meteor and RV Maria S Merian. We present retrieved Integrated Water Vapor (IWV), Liquid Water Path (LWP) and temperature and humidity profiles as a unified, quality-controlled, multi-site dataset on a three second temporal resolution for a core period between January 19, 2020 and February 14, 2020 in which all instruments were operational. 14-channel K- and V-band measurements were performed at BCO and aboard the RV Meteor, and combined radar-radiometer measurements of a W-band Doppler radar with a single-channel radiometer instrument were conducted at 89 GHz onboard the RV Meteor and RV Maria S Merian. Mean IWV of 31.8 kgm⁻² matches independent radiosoundings at BCO with a rootmean-square difference of 1.1 kgm⁻². Mean LWP conditions in confident cloudy, non-precipitating conditions ranged between 66.5 gm⁻² at BCO to 40.4 gm⁻² aboard the RV Maria S Merian. Aboard the ships, 90 % of LWP was below 120 gm⁻² with an uncertainty of 30 % at LWP of 50 gm⁻². Up to 30 % of confident cloudy profiles ranged below the LWP detection limit due to optically thin clouds.

The data set comprises of processed raw-data (Level 1), full quality-controlled post-processed instrument data (Level 2), a unified temporal resolution (Level 3), and a ready-to-use multi-site time series of IWV and LWP (Level 4), available to the public via AERIS (https://doi.org/10.25326/454, Schnitt et al., 2023). The data set complements the airborne LWP measurements conducted during EUREC⁴A and provides a benchmark tool for model-observation studies.