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Atmospheric Radiation Measurement Program facilities newsletter, January 2000

Description: The subject of this newsletter is the ARM unmanned aerospace vehicle program. The ARM Program's focus is on climate research, specifically research related to solar radiation and its interaction with clouds. The SGP CART site contains highly sophisticated surface instrumentation, but even these instruments cannot gather some crucial climate data from high in the atmosphere. The Department of Energy and the Department of Defense joined together to use a high-tech, high-altitude, long-endurance class of unmanned aircraft known as the unmanned aerospace vehicle (UAV). A UAV is a small, lightweight airplane that is controlled remotely from the ground. A pilot sits in a ground-based cockpit and flies the aircraft as if he were actually on board. The UAV can also fly completely on its own through the use of preprogrammed computer flight routines. The ARM UAV is fitted with payload instruments developed to make highly accurate measurements of atmospheric flux, radiance, and clouds. Using a UAV is beneficial to climate research in many ways. The UAV puts the instrumentation within the environment being studied and gives scientists direct measurements, in contrast to indirect measurements from satellites orbiting high above Earth. The data collected by UAVs can be used to verify and calibrate measurements and calculated values from satellites, therefore making satellite data more useful and valuable to researchers.
Date: February 16, 2000
Creator: Sisterson, D.L.
Partner: UNT Libraries Government Documents Department

Atmospheric Radiation Measurement Program facilities newsletter, February 2003.

Description: Cloudiness Inter-comparison IOP--Clouds are an important part of Earth's energy system. We take clouds for granted, but their role in weather and climate is considerable. Without clouds, life on Earth would be impossible. By helping to regulate surface temperatures, clouds establish livable conditions on the planet. Clouds produced by water vapor condensation play a complicated role in our climate system. Clouds decrease the amount of sunlight received by Earth's surface. Decreased sunlight reduces evaporation driven by sunlight and thus reduces cloud formation. With fewer clouds, Earth receives more sunlight, which eventually increases evaporation and cloud production. On the other hand, clouds also trap longwave (infrared) radiation emitted by Earth, as does water vapor. This heating effect increases evaporation. In summary, cloud formation is a complex, self-regulating, cyclic process. The SGP CART site is conducting a Cloudiness Inter-comparison IOP (intensive operational period) from mid-February through mid-April. The central facility near Lamont, Oklahoma, currently is home to several cloud-measuring instruments. The process of measuring cloudiness has always been somewhat subjective. Cloud measurements were once made by solely human observation, but new technology enables instruments to view the sky and make the more objective cloud measurements needed by both operational and research meteorologists. The SGP site currently operates eight different instruments that make cloud-related measurements. Data are collected on cloud cover, cloud top and base location, cloud water vapor and liquid water, sunshine duration and amount, and cloud number and area. During the Cloudiness Inter-comparison IOP, three additional cloud-measuring instruments are being brought to the CART site to be tested and assessed against the current instruments. Researchers are interested in testing whether the additional instruments can collect better data during nighttime hours, when visible light is not available for measurements. One of the three additional instruments is a commercially produced analyzer called the ...
Date: February 28, 2003
Creator: Holdridge, D. J.
Partner: UNT Libraries Government Documents Department

Atmospheric Radiation Measurement Program facilities newsletter, January 2001.

Description: In the realm of global climate modeling, numerous variables affect the state of the atmosphere and climate. One important area is soil moisture and temperature. The ARM Program uses several types of instruments to gather soil moisture information. An example is the soil water and temperature system (SWATS). A SWATS is located at each of 21 extended facility sites within the CART site boundary. Each system is configured to measure soil moisture and temperature at eight distinct subsurface levels. A special set of probes used in the SWATS measures soil temperature, soil-water potential, and volumetric water content. Sensors are placed at eight different depths below the soil surface, starting at approximately 5 cm (2 in.) below the surface and ending as deep as 175 cm (69 in.). Each site has two identical sets of probes buried 1 m (3.3 ft) apart, to yield duplicate measurements as a quality control measure. At some sites, impenetrable soil or rock layers prevented installation of probes at the deeper levels. The sensors are connected to an electronic data logger that collects and stores the data. Communication equipment transfers data from the site. All of the electronic equipment is housed in a weatherproof enclosure mounted on a concrete slab.
Date: February 5, 2001
Creator: Holdridge, D. J.
Partner: UNT Libraries Government Documents Department

Atmospheric radiation measurement program facilities newsletter, January 2002.

Description: Central Facility Benefits from Improvements--Three current projects are improving the ARM SGP central facility near Lamont, Oklahoma: construction of an instrument maintenance facility, installation of an instrument to measure carbon dioxide flux, and construction of a platform to accommodate instruments brought to the site by visiting scientists. Instrument Maintenance Facility--Construction of the instrument maintenance facility began on November 26, 2001. Being assembled from three mobile trailer units rescued from Argonne National Laboratory's excess equipment pool, this facility will add almost 2,400 square feet of space and will allow significant expansion of the onsite electronics laboratory that repairs and troubleshoots malfunctioning equipment. The facility will also consolidate instrument parts and repairs and provide much-needed office space and indoor restroom facilities for the field and electronics technicians who work at the central facility. New Carbon Dioxide Flux Measurements--In mid-December, scientists from Lawrence Berkeley Laboratory and the University of Nebraska installed an instrument that measures carbon dioxide flux in a wheat field near the 60-meter tower at the central facility. Measurements of carbon dioxide flux during the winter wheat growing season will be used to validate measurements taken by similar equipment mounted on the nearby tower. Several similar systems may be installed in surrounding fields during January. All equipment will be removed before the May wheat harvest. New Platform for Guest Instruments--The guest instrument facility will be receiving an addition soon, in the form of an elevated deck on the north side of the building. The deck, measuring 15 feet by 30 feet, will accommodate instrumentation brought to the CART site by visiting scientists. The SGP CART site hosts an increasing number of guest instruments each year. The addition will provide adequate space for the temporary instrument installations.
Date: February 1, 2002
Creator: Holdridge, D. J.
Partner: UNT Libraries Government Documents Department