60 Meter Tower

The 60-meter tower at the SGP Central Facility hosts a variety of meteorological instruments that measure temperature, humidity, water vapor and carbon dioxide. The Precision Carbon Dioxide Mixing Ratio System sits at the base of it in the white shelter, which takes high-precision carbon dioxide mixing ratios samples at 2, 4, 25, and 60 meters above ground from the tower.

Aerosol Observing System

Since 1996, the Aerosol Observing System has been the primary platform for in situ aerosol surface measurements at the SGP site. Containing nearly 20 different instruments, the Aerosol Observing System measures aerosol optical properties to understand how particles interact with solar radiation and influence the Earth's radiation balance.

Radiometer Calibration Facility

The Radiometric Calibration Facility provides shortwave radiometer calibrations traceable to the World Radiometric Reference—an internationally recognized standard for solar (shortwave) irradiance measurement. This facility is designed to simultaneously calibrate up to 100 radiometers in outdoor conditions similar to those experienced by field instruments during routine monitoring. Instruments calibrated at the site include 1) pyrheliometers, which are used to measure direct (beam) solar irradiance; 2) pyranometers, which have a hemispheric (fish-eye) field of view and are designed to measure the total direct and diffuse (sky) irradiance on a flat surface; and 3) pyrgeometers, which are similar to pyranometers, but have an outer blocking filter to eliminate the high energy solar irradiance and measure only the longwave, thermal (or infrared) radiation from the atmosphere.

Equipment Repair Lab

In order to reduce costs, the Electronics Repair Laboratory (ERL) was opened in 1998 to repair instruments on site. By reducing the number of repairs made by manufacturers and eliminating shipping costs, the ERL has decreased operating costs and shortened instrument downtime - by as much as several months - for instruments that otherwise would be shipped overseas for repairs.

The ERL provides a wide range of diagnostic and repair services. Instrument components routinely replaced in the ERL include power supplies, shadowband motors, wind sensor bearings, cable and connectors, universal power supply (UPS) batteries, and electronic boards. On-site repair is available for data loggers; electronic boards; operating systems; storage modules; modems; air pumps; motors; various instrument components; and wind, humidity, and temperature sensors.

Main Office

Visitors check in at the front office. The front office also has conference rooms for team meetings and presentations and a lunch room available to all visitors.

Raman Lidar

Developed specifically for the ARM Facility, the Raman lidar is an active, ground-based laser remote sensing instrument that measures water-vapor mixing radio and several cloud and aerosol properties. This lidar was the first turn-key operational Raman lidar in the world and has been in operating since 1996.

Doppler Lidar and Radar Wind Profiler

Similar to a radar, the Doppler lidar operates with pulses of energy that are transmitted into the atmosphere; the energy scattered back to the transceiver is collected and measured as a time-resolved signal. This provides range- and time-resolved measurements of radial velocity and attenuated backscatter.

The radar wind profiler measures wind profiles, backscattered signal strength, and virtual temperature profiles. Virtual temperatures are recovered by transmitting an acoustic signal vertically and measuring the electromagnetic energy scattered from the wavefront.

Ka-Band Scanning ARM Cloud Radar

Measurements collected with the Ka-Band Scanning ARM Cloud Radar (Ka-SACR) are co-polar and cross-polar radar reflectivity, Doppler velocity, spectra width and spectra when not scanning, and linear depolarization ration. Rather than focusing on plan position indicator, or PPI, scans, the Ka-SACR utilizes range height indicator, or RHI, scans at numerous azimuths to obtain cloud volume data. Each Ka-band radar is paired with a second radar, either a W-band or X-band, depending upon location.

Learn more on the ARM YouTube channel.

Ka-Zenith Radar

A series of radars and lidars at the SGP are used to measure a variety of atmospheric properties. Due to the narrow antenna beamwidth, ARM's scanning cloud radars utilize scanning strategies that are unlike typical weather radars. ARM scanning cloud radars are fully coherent dual-frequency, dual-polarization Doppler radars mounted on a common scanning pedestal. Scanning pedestals include a Ka-band radar and a W-band or X-band radar, depending on the facility location.

Guest User Facility

In 2002, a guest instrument facility was established at the SGP site to support the needs of visiting scientists. Ideally suited to support a wide range of experiments, the guest instrument facility allows scientists to gather additional data using their own instruments.

The guest facility features a climate-controlled main building, an elevated instrument platform, and a concrete instrument patio. This facility is also outfitted with uninterrupted power supply (UPS) outlets, network connectivity, telephones, and a consistent power source to support user needs.

Learn more on the ARM website.

Optical Field

One of two instrument fields, the optical instrument field features a variety of instrumentation that measures optical properties, such as the infrared spectral radiance, cloud-base height, vertical cloud visibility, water vapor and liquid molecules, and fractional sky cover.

Radiometer Field

The second of the two instrument fields, the radiometer instrument field hosts two rows of radiometers, including pyrheliometers, pyranometers, and pyrgeometer, to measure different aspects of atmospheric and radiant flux.

Optical Trailer

A variety of instrumentation that measures optical properties, such as the infrared spectral radiance, cloud-base height, vertical cloud visibility, water vapor and liquid molecules, and fractional sky cover, are hosted at the Optical Trailer. Instrumentation found at the Optical Trailer include the atmospheric emitted radiance interferometer, shortwave spectroradiometer, shortwave array spectroradiometer-hemispheric and zenith, and sunphotometer.

ARM Aerial Facility Routine Measurements

Routine measurements of aerosol and carbon have been collected over the Central Facility since 2000 through a series of field campaigns. From 2000-2005, in a joint effort with the Climate Monitoring and Diagnostics Laboratory (CMDL) of the U.S. National Oceanic and Atmospheric Administration (NOAA), the emphasis was in situ aerosol profiling for measurements of aerosol absorption and scattering, particle chemistry, and carbon. After 2005, the emphasis for routine flight measurements transitioned to the carbon cycle under a series of campaigns known as the ARM Airborne Carbon Measurements (ARM-ACME).

Balloon-Borne Sounding System

Site operators use the balloon-borne sounding system, or SONDE, to launch weather balloons four times a day at the SGP site. Radiosondes attached to the balloons provide vertical profiles of both the thermodynamic state of the atmosphere and wind speed and direction.

Eddy Correlation Flux Measurement System

The eddy correlation flux measurement system provides in situ, 30- minute measurements of the surface turbulent fluxes of momentum, sensible heat, latent heat, and carbon dioxide. The fluxes are obtained with the eddy covariance technique, which involves correlation of the vertical wind component with the horizontal wind component, air temperature, the water vapor density, and the carbon dioxide concentration.