An official website of the United States government
blue sky with white clouds

World’s premier ground-based observations facility advancing atmospheric research

Power Your Research with ARM

The U.S. Department of Energy’s Atmospheric Radiation Measurement (ARM) User Facility provides 30-plus years of atmospheric measurements, including data sets from all seven continents and five oceans, to advance the understanding of the Earth’s atmosphere.

Access ARM Data

ARM collects continuous measurements and develops data products that promote the advancement of earth system models.

New to ARM?

As a U.S. Department of Energy Office of Science user facility, ARM makes its data freely available to scientists around the world.

Use ARM Facilities for Your Research

Explore the ARM Observatories

Read the Latest from ARM

Portrait of Alfonso Ladino-Rincon

Features

PhD Student Helps Bring Py-ART, Open Radar Data to the Masses

17 March 2026

Alfonso Ladino-Rincon, who attended ARM's 2024 summer school, works on projects to support the growth of the open science community.

Charting a Bold Course for AI Integration

12 March 2026

A new phased approach for artificial intelligence (AI) prioritizes transparent governance, AI‑ready infrastructure, and user engagement to accelerate discovery across the ARM community.

Researchers Apply ARM Data to Refine Aerosol-Cloud Interaction Simulations

18 February 2026

A recent paper uses observations from ARM and other field campaigns to evaluate simulations from the U.S. Department of Energy's Energy Exascale Earth System Model at kilometer-scale resolution.

Six time-height plots of Southern Great Plains (SGP) Ka-Band ARM Zenith Radar (KAZR) general sensitivity (GE) and moderate sensitivity (MD) reflectivity, censor mask, and classification mask highlight the insects in the boundary layer (or biota, as indicated in the classification mask plots) on September 5, 2025. Plots were created by Marqi Rocque, Pacific Northwest National Laboratory.

Data Announcements

Characterized, Calibrated Fixed-Site KAZR Data Available for 2025

10 April 2026

These newly released data from the Ka-Band ARM Zenith Radar (KAZR) have undergone calibration, correction, and quality control processes beyond ARM’s standard quality checks and corrections.

Cloud Type Classification Product Released for CoURAGE and BNF Deployments

24 March 2026

The product provides an automated cloud type classification for the Coast-Urban-Rural Atmospheric Gradient Experiment (CoURAGE) in Baltimore, Maryland, and ARM's Bankhead National Forest (BNF) atmospheric observatory in Alabama.

Synoptic Weather Regime Classification Product Now Available for CoURAGE Campaign

25 February 2026

This machine learning value-added product for the 2024–2025 Coast-Urban-Rural Atmospheric Gradient Experiment (CoURAGE) provides key insights into the variability of large-scale circulations over the Baltimore, Maryland, region.

Clouds roll across the sky over the Kennaook/Cape Grim area.

Research Highlights

New Insights into Aerosol-cloud Interaction Over the Eastern North Atlantic

16 March 2026

While a non-monotonic (“inverted-V”) cloud response to aerosol perturbation—initial cloud thickening via precipitation suppression followed by enhanced evaporative dissipation—has been previously reported, its meteorological conditioning remains unresolved. Using a deep-learning framework to objectively classify Eastern North Atlantic synoptic regimes, we show that the cloud response is strongly regime-dependent and that the U.S. Department of Energy's earth system model (E3SMv2) systematically overestimates liquid water loss, particularly in dynamically complex, precipitating environments with strong vertical motion. These biases are linked to uncertainties in models representing drizzle, entrainment, and turbulent processes.

Evaluating Satellite and Ground-Based Measurements of Earth’s Radiation

16 March 2026

Earth’s radiant energy budget represents the balance between the energy Earth receives from the sun and the energy Earth sends back into space. The radiant energy budget drives planetary dynamics, thermodynamics, and the water cycle. Researchers often use satellite data to estimate how much sunlight and heat move through the atmosphere. In this study, researchers compared radiative flux estimates calculated from satellite data and those calculated from ground-based sensors at the U.S. Department of Energy Atmospheric Radiation Measurement (ARM) User Facility's Eastern North Atlantic (ENA) site. They found that satellite measurements overestimate surface downwelling fluxes. On the other hand, fluxes based on observed cloud and thermodynamic data from ground-based sensors showed no such bias. The overestimation of satellite fluxes was attributed to inaccuracies in variables like temperature and cloud properties within the retrieval algorithm.

Dampening of the Precipitation Susceptibility to Aerosols from Cloud Turbulence

14 March 2026

Warm rain formation is a critical factor for cloud modulation and the response of precipitation to aerosol loading. However, it remains challenging to accurately represent in atmospheric models across scales because the driving process, droplet collision-coalescence, involves interactions at micro‐scales that interact with larger scales. The current study, using observations and a state-of-the-art cloud model, investigates the role of small-scale turbulence in modulating the precipitation response to aerosol loading through drop coalescence.

ARM Logo

Follow Us:

Keep up with the Atmospheric Observer

Updates on ARM news, events, and opportunities delivered to your inbox

Subscribe Now

ARM User Profile

ARM welcomes users from all institutions and nations. A free ARM user account is needed to access ARM data.

Atmospheric Radiation Measurement (ARM) | Reviewed March 2025