DOI: 10.4121/89e54cff-4e52-4075-9690-1c81e47ef8ba.v1
title: TU Delft Cloud radar data - MARA Cabauw Vertical Profiles

description: <strong>Description:</strong>Vertical profiles of clouds and precipitation measured by 94 GHz cloud radar.<br>This dataset contains vertical profiles of clouds and precipitation observed using a dual-polarization frequency-modulated continuous-wave (FMCW) cloud radar located at the atmospheric site Cabauw. The radar, developed by Radiometer Physics GmbH (RPG-FMCW94-DP type) and named Mobile Atmospheric RAdar (MARA), operates at 94 GHz. It employs simultaneous transmission and simultaneous reception (STSR) mode and its beamwidth is 0.56°. There is a rain/snow/fog mitigation system, comprising a dew blower and a heater which prevent the accumulation of liquid drops and ice on the hydrophobic antenna radomes, therefore mitigating attenuation caused by the presence of liquid water on the antennas.<br>Measurements are collected at a fixed elevation angle (90°). MARA includes an embedded passive channel at 89 GHz, enabling Liquid Water Path (LWP) retrieval using the same receiving antenna. Additionally, it is coupled with a HATPRO G5 microwave radiometer (MARIO), providing collocated radiometric measurements at the same temporal resolution. A built-in weather station (Vaisala WXT536) also records ground-level meteorological conditions.<br>In terms of calibration, the transmit power is continuously monitored, and the radar receiver (including the receiving antenna) undergoes calibration every six months using liquid nitrogen calibration. Short-term calibration is provided through periodic Dicke switching. Prior to the semiannual calibration procedure, the hydrophobic antenna radomes are replaced.<br>This dataset is part of a broader collection from the Department of Geoscience and Remote Sensing (GRS) at TU Delft, published within the Ruisdael Observatory framework (https://ruisdael-observatory.nl/). This dataset will continue to be updated over time while the cloud radar remains operational.<br><strong>List of variables:</strong>* sensor and site parameters* measurement specifications* processing specifications* weather station measurements* LWP in the looking direction of the cloud radar * profiles of temperature, absolute and relative humidity (MARIO)* Doppler spectra (HH and VV) and covariance spectrum (LV0 files)* Equivalent reflectivity factor (LV1 files)* Doppler variables (LV1 files)* Polarimetric variables (LV1 files)<br><strong>Relevance:</strong>The dataset "Vertical profiles of precipitation, ice and mixed-phase clouds, and liquid water clouds at 94 GHz" provides important information for understanding cloud microphysics and atmospheric processes. By using radar reflectivity, Doppler variables and Doppler spectra at 94 GHz, the dataset enables detailed characterization of hydrometeor vertical structures, distinguishing between precipitation, ice, mixed-phase, and liquid water cloud layers. This high-frequency radar data is particularly sensitive to small cloud particles, making it highly relevant for studying cloud formation, phase transitions, and precipitation development. Such profiles are essential for validating satellite retrievals, improving weather and climate models, and enhancing our understanding of cloud–radiation interactions.