Characterized and Corrected Radar Data Released for EPCAPE Field Campaign

Published: 20 November 2025

Scientists interested in coastal marine clouds can now use characterized and corrected radar data from the 2023–2024 Eastern Pacific Cloud Aerosol Precipitation Experiment (EPCAPE). These data are considered b1-level, meaning they underwent calibration, correction, and quality control processes beyond the Atmospheric Radiation Measurement (ARM) User Facility’s standard quality checks and corrections.

ARM produced b1-level data for the following radars that operated in La Jolla, California, as part of EPCAPE:

Three panels are filled in with blue and white spaces indicating available and unavailable data, respectively. KAZR data were nearly 100% available for all of EPCAPE, while data were largely available from the KASACR and WSACR. — Data availability is shown for the Ka-Band ARM Zenith Radar (KAZR), Ka-Band Scanning ARM Cloud Radar (KASACR), and W-Band Scanning ARM Cloud Radar (WSACR) during the 2023–2024 EPCAPE campaign. All images in this announcement were created by Marqi Rocque, Pacific Northwest National Laboratory.

During EPCAPE, the KASACR, WSACR, and KAZR observed daily and seasonal cloud property variations in a coastal marine environment. The KAZR was part of the main instrument site on the Ellen Browning Scripps Memorial Pier, while the KASACR and WSACR were about 3 kilometers southeast atop Mount Soledad. The KASACR and WSACR provided rapid scans over the Pacific Ocean every two minutes for almost a full year, resulting in an extensive cloud radar data set.

ARM staff applied reflectivity offsets and meteorological echo masks to each of the radar data sets. The masks allow scientists to quickly remove background noise and clutter when needed.

The daily average reflectivity differences between the EPCAPE WSACR and KAZR in shallow clouds are shown for one month in 2023.

This figure shows the KAZR general sensitivity (GE) mode reflectivity, linear depolarization ratio, and classification mask for an EPCAPE shallow cloud case mixed with biota on May 12, 2023. — This figure shows the KAZR general sensitivity (GE) mode reflectivity, linear depolarization ratio, and classification mask for an EPCAPE shallow cloud case mixed with biota—organisms such as insects, birds, or bats—on May 12, 2023.

Staff also developed a new classification mask for the KAZR. The mask identifies additional non-meteorological signals, including insects, which were frequently observed at Scripps Pier.

The corrected and characterized data sets are available now in CfRadial format.

More information about the data is available in the EPCAPE b1-level radar data processing technical report.

Access the KASACR, WSACR, and KAZR b1-level data in the ARM Data Center. (To download the data, first create an ARM account.)

For questions or to report data issues, please contact the ARM radar team.

To cite the data, please use the following DOIs: