Atmospheric Radiation Measurement (ARM) user facility
As a U.S. Department of Energy scientific user facility with measurement capabilities across the globe, the Atmospheric Radiation Measurement (ARM) facility is used by scientists to obtain long-term measurements of cloud and aerosol properties, radiative energy, meteorology, precipitation, and surface properties in diverse locales for studying atmospheric processes and improving earth system models. All data are freely available online at www.arm.gov.