Atmospheric Radiation Measurement (ARM) user facility

Three new scanning microwave radiometers (left) undergo testing in the instrument field at the Southern Great Plains site's Central Facility.

ARM is a multi-platform scientific user facility with instruments at fixed and varying locations around the globe for obtaining continuous field measurements of atmospheric data.
Global Network Location
1989 Start of Operations
1,113 (FY 2022) Number of Users


The Atmospheric Radiation Measurement (ARM) user facility ( is a multi-laboratory scientific user facility with the objective of providing a detailed and accurate description of the Earth’s atmosphere in diverse climate regimes to resolve the uncertainties in climate and earth system models. ARM provides the national and international research community with strategically located in situ and remote sensing observatories designed to improve the understanding and representation, in climate and earth system models, of clouds and aerosols as well as their interactions and coupling with the Earth’s surface.

ARM operates a global network of in situ and remote sensing atmospheric observatories in climatically significant locations to sample continental and marine conditions in diverse environments with a goal to improve capabilities of models to make high quality predictions across the globe. There are three fixed sites (U.S. Southern Great Plains, North Slope of Alaska, and the Azores) and three mobile facilities to explore science questions beyond those addressed by ARM's fixed sites.  ARM also has an aerial measurement capability to complement the ground measurements by providing information on spatial variability as well as detailed information on aerosol and cloud microphysical properties that can be obtained only through in situ measurements. ARM supports the development of scientific data products from ARM observations and hosts a data archive that provides scientists with quality-assured data in near real time. Users may access ARM data free of charge and may propose experiments or field campaigns using the ARM fixed, mobile, and aerial facilities.


ARM provides the climate community with state-of-the-art observational data to understand the role of clouds and aerosols in controlling the Earth’s energy balance.  ARM’s multiple instrument systems, long-term data records, high frequency measurements, and three-dimensional capabilities provide a unique resource for studying aerosol and cloud processes, as well as their interactions and coupling with the Earth’s surface. ARM data has led to significant enhancements to the radiation, aerosol, and cloud components of major climate models.  Nevertheless, cloud and aerosol feedbacks remain the largest source of uncertainty in climate sensitivity estimates. Over the next decade, ARM will couple observations with high-resolution atmospheric models to accelerate the application of ARM observations for understanding key atmospheric processes; provide unique observations of critical high-latitude aerosol and cloud processes; enhance ARM’s aerial capabilities to enable critical in situ observations of the spatially variable structure of the atmosphere, aerosols, and clouds; develop data products, analysis tools, and computational capabilities that facilitate the scientific community’s use of cutting-edge ARM instruments, such as scanning cloud radars; provide the observations to support integrated studies of the key aerosol, boundary layer, and convective processes driving aerosol-cloud-precipitation-surface-radiation interactions in continental, marine, and high-latitude environments.