Additional Enhanced Cloud Microphysics Data Released to Production

Published: 11 August 2026

New production data are available from the Atmospheric Radiation Measurement (ARM) User Facility’s Improved Continuous Baseline Microphysical Retrieval (MICROBASE) product with uncertainty estimation. Production or baseline value-added products (VAPs) are reviewed and verified as compliant with ARM data standards and are processed automatically or manually on ARM production servers.

In addition, to unify current and previously released versions of MICROBASE products under one name, ARM recently reprocessed existing MICROBASEKA and MICROBASEKAPLUS data, moving them from evaluation to production and renaming them as MICROBASE.

MICROBASE is designed to provide continuous, high-temporal-resolution profiles of cloud microphysical properties such as liquid/ice water content and liquid/ice effective radius. This VAP aims to support studies focusing on the process-level understanding of cloud and precipitation formation and evolution, as well as cloud particle phase partitioning and radiative heating rates. In addition, these long-term data can serve as ground truth for evaluating model performance, both for specific cases of interest and in a statistical context.

More information on MICROBASE, including the technical report, is available on the VAP web page.

New MICROBASE production data are available for the following ARM sites and date ranges:

• the North Slope of Alaska (NSA) central facility at Utqiaġvik (formerly Barrow) from January 1, 2020, through December 31, 2025
• the Southern Great Plains (SGP) Central Facility near Lamont, Oklahoma, from June 1, 2025, through February 27, 2026
• the ARM Mobile Facility site in La Jolla, California, during the Eastern Pacific Cloud Aerosol Precipitation Experiment (EPCAPE) from February 15, 2023, through February 14, 2024.

SGP MICROBASEKAPLUS data from January 18, 2011, through December 31, 2021, and MICROBASEKA data from April 22, 2011, through June 6, 2011, have been moved from evaluation to production and renamed as MICROBASE to reflect that all data have been reprocessed with the most recent algorithm. This completes a backfill of SGP MICROBASE data.

In addition, MICROBASEKA and MICROBASEKAPLUS data have been reprocessed and renamed as MICROBASE for the following ARM Mobile Facility deployments and date ranges:

• the TRacking Aerosol Convection interactions ExpeRiment (TRACER) in La Porte, Texas, from October 1, 2021, through September 30, 2022
• the Cold-Air Outbreaks in the Marine Boundary Layer Experiment (COMBLE) in Andenes, Norway, from December 1, 2019, through May 31, 2020
• the Layered Atlantic Smoke Interactions with Clouds (LASIC) campaign on Ascension Island in the South Atlantic Ocean from August 1, 2016, through September 30, 2017
• the ARM Madden-Julian Oscillation Investigation Experiment – Gan Island (AMIE-GAN) in the Maldives from October 9, 2011, through February 7, 2012.

The current plan is to release additional SGP MICROBASE data within one month after the Ka-Band ARM Zenith Radar Active Remote Sensing of CLouds (KAZRARSCL) product becomes available. MICROBASE uses KAZRARSCL as input data.

Additional NSA MICROBASE data will be processed once the calibrated KAZRARSCL product from that site becomes available. The current gap in NSA MICROBASE data from July 2014 through December 2019 is planned to be backfilled by the end of fiscal year 2026.

All existing MICROBASEKAPLUS data from ARM’s Eastern North Atlantic (ENA) atmospheric observatory in the Azores are expected to be reprocessed and renamed as MICROBASE once KAZR calibration tasks are completed.

Ongoing work aims to integrate MICROBASE into the ARM Operational Ground-Based Retrieval Evaluation for Clouds (OGRE-CLOUDS) framework. The OGRE-CLOUDS team is evaluating improvements to cloud microphysics retrievals through radiative closure studies and comparisons with instrument simulator data. Through this process, the development team anticipates a continuous improvement of the cloud microphysical estimates.

Access the MICROBASE data in the ARM Data Center. (To download the data, first create an ARM account.)

Please send product-related questions or feedback to MICROBASE translator Min Deng, OGRE-CLOUDS Principal Investigator Michael Jensen, and/or VAP developer Meng Wang.

To cite the MICROBASE data, please use doi:10.5439/1900609. This DOI supersedes the DOIs for the legacy data products MICROBASEKA (doi:10.5439/1633042) and MICROBASEKAPLUS (doi:10.5439/1768890), as both legacy products have been replaced by the MICROBASE product. The legacy DOIs remain available to support existing references but redirect to the current MICROBASE product.