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Atmospheric Radiation Measurement Program facilities newsletter, July 1999.

Description: Summer research efforts continue in July with the SGP99 Hydrology Campaign headed by the US Department of Agriculture, Agricultural Research Service. Other participants are the National Aeronautics and Space Administration (NASA), the National Oceanic and Atmospheric Administration, and the ARM Program. This campaign focuses on measuring soil moisture by using satellite-based instruments and takes place July 7--22, 1999. Soil moisture is an important component of Earth's hydrologic cycle and climate, but the understanding of it and the ability to measure it accurately are limited. Scientists need to understand soil moisture better so that it can be incorporated correctly into general circulation models. As an important factor in growing crops, soil moisture dictates a farmer's success or failure. Too much soil moisture can drown out croplands and cause flooding, whereas too little can lead to drought conditions, robbing crops of their life-supporting water. Decisions about which crops to plant and other land use issues depend on the understanding of soil moisture patterns. Soil moisture can be measured in various ways. ARM employs several direct methods using soil moisture probes buried from 1 inch to 6.5 feet below the surface. One type of probe has two stainless steel screens separated by a piece of fiberglass. Electrical resistance, which is a function of soil moisture content, is measured between the screens. Another type of probe measures soil temperature and the increase in temperature after the soil is heated by small heating element. From this measurement, the volume of water in the soil can be calculated.
Date: July 30, 1999
Creator: Sisterson, D. L.

Atmospheric radiation measurement program facilities newsletter, August 1999.

Description: With the end of summer drawing near, the fall songbird migration season will soon begin. Scientists with the ARM Program will be able to observe the onset of the migration season as interference in the radar wind profiler (RWP) data. An RWP measures vertical profiles of wind and temperature directly above the radar from approximately 300 feet to 3 miles above the ground. The RWP accomplishes this by sending a pulse of electromagnetic energy skyward. Under normal conditions, the energy is scattered by targets in the atmosphere. Targets generally consist of atmospheric irregularities such as variations in temperature, humidity, and pressure over relatively short distances. During the spring and fall bird migration seasons, RWP beam signals are susceptible to overflying birds. The radar beams do not harm the birds, but the birds' presence hampers data collection by providing false targets to reflect the RWP beam, introducing errors into the data. Because of the wavelength of the molar beam, the number of individuals, and the small size of songbirds' bodies (compared to the larger geese or hawks), songbirds are quite likely to be sampled by the radar. Migrating birds usually fly with the prevailing wind, making their travel easier. As a result, winds from the south are ''enhanced'' or overestimated in the spring as the migrating birds travel northward, and winds from the north are overestimated in the fall as birds make their way south. This fact is easily confirmed by comparison of RWP wind data to wind data gathered by weather balloons, which are not affected by birds.
Date: September 3, 1999
Creator: Sisterson, D.L.

Atmospheric Radiation Measurement Program Facilities Newsletter - June 1999.

Description: The Mesoscale Convective Systems (MCSs) Campaign is underway at the SGL CART site and will continue through September 1999. This field study is investigating the small-scale physics of precipitation and the convective dynamics of MCSs in the middle latitudes. An MCS is defined as a precipitation system that is 10--300 miles wide and contains deep convection at some time in its life span. MCSs occur in the midlatitudes of the US and can include large, isolated thunderstorms, squall lines, and mesoscale convective complexes.
Date: July 15, 1999
Creator: Holdridge, D. J., ed. & Sisterson, D. L.

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.

Atmospheric Radiation Measurement Program facilities newsletter, March 2000

Description: The Atmospheric Radiation Measurement Program (ARM Program) is sending a copy of the ARM Video, an education overview of their program. In the video you will see and hear ARM scientists describe the importance of studying climate and climate change. It also contains a tour of some ARM sites and a look at state-of-the-art meteorological instrumentation, along with background information about the radiation budget and the complexity of climate modeling. The video was produced by the US Department of Energy.
Date: April 3, 2000
Creator: Sisterson, D. L.

Atmospheric Radiation Measurement Program facilities newsletter, May 2000.

Description: This month the authors will visit an ARM CART site with a pleasant climate: the Tropical Western Pacific (TWP) CART site, along the equator in the western Pacific Ocean. The TWP locale lies between 10 degrees North latitude and 10 degrees South latitude and extends from Indonesia east-ward beyond the international date line. This area was selected because it is in and around the Pacific warm pool, the area of warm sea-surface temperatures that determine El Nino/La Nina episodes. The warm pool also adds heat and moisture to the atmosphere and thus fuels cloud formation. Understanding the way tropical clouds and water vapor affect the solar radiation budget is a focus of the ARM Program. The two current island-based CART sites in the TWP are in Manus Province in Papua New Guinea and on Nauru Island.
Date: June 1, 2000
Creator: Sisterson, D.L.

Atmospheric Radiation Measurement Program facilities newsletter, April 2000

Description: This issue of the Atmospheric Radiation Measurement Program (ARM Program) monthly newsletter is about the ARM Program goal to improve scientific understanding of the interactions of sunlight (solar radiation) with the atmosphere, then incorporate this understanding into computer models of climate change. To model climate accurately all around the globe, a variety of data must be collected from many locations on Earth. For its Cloud and Radiation Testbed (CART) sites, ARM chose locations in the US Southern Great Plains, the North Slope of Alaska, and the Tropical Western Pacific Ocean to represent different climate types around the world. In this newsletter they consider the North Slope of Alaska site, with locations at Barrow and Atqasuk, Alaska.
Date: May 5, 2000
Creator: Sisterson, D. L.

Atmospheric Radiation Measurement Program facilities newsletter, February 2000

Description: This issue of the ARM facilities newsletter discusses the Spring 2000 cloud intensive observation period, March 1--21, 2000. The month of March brings researchers to the SGP CART site to participate in the Spring 2000 Cloud IOP. The purpose is to gather data about the three-dimensional structure and distribution of clouds over the CART site. This effort will help to produce a more accurate representation of the clouds and their influence on weather and climate for use in computer modeling.
Date: March 24, 2000
Creator: Sisterson, D. L.

Atmospheric Radiation Measurement Program facilities newsletter, September 2000

Description: This is the third water vapor IOP and it will focus on the lower portions of the atmosphere. Again, scientists will work to achieve absolute calibrations of water vapor instrumentation. For this purpose, several instruments will be deployed, and measurements will be compared. Instruments to be used include radiosondes, Raman lidar, chilled-mirror hygrometers, surface meteorological observation station (SMOS) towers, a variety of microwave radiometers, and global positioning systems (GPS). The current experiment has two goals. The first is to characterize the accuracy of the water vapor measurements, especially the daily operational observations being made around the clock in the lower levels of the atmosphere at the CART site. The second goal is to develop techniques for improving the accuracy of these observations in order to obtain the best possible water vapor measurements under a wide range of atmospheric conditions.
Date: September 19, 2000
Creator: Sisterson, D. L. & Holdridge, D. J., ed.

Atmospheric Radiation Measurement Program facilities newsletter, August 2000

Description: The primary objective of this USDA program is to provide information to the agricultural community about the geographic and temporal climatology of UV-B radiation. Scientists also use the data to determine changes in stratospheric ozone levels, cloud cover, and aerosols as they pertain to UV-B radiation and to improve the understanding of factors that control transmission of UV-B radiation. Advances have been made in areas of agriculture, human health effects, ecosystem studies, and atmospheric science. ARM Program personnel are excited about being a part of such a worthwhile effort.
Date: August 30, 2000
Creator: Sisterson, D. L.

Atmospheric Radiation Measurement Program facilities newsletter, June 2001.

Description: The ARM Program studies clouds, sunlight, and their interactions to understand how they affect Earth's climate. One of the many instruments used to look at clouds at the SGP CART site is the micropulse lidar (MPL; ''lidar'' was coined from ''light distance and ranging''). The ARM Program operates five MPLs. One is at the SGP central facility; one is at the North Slope of Alaska CART site in Barrow, Alaska; and three are for use at the Tropical Western Pacific site on Nauru and Manus islands. The MPL is a remote sensing instrument used to measure the height of overhead clouds and particles. An eye-safe laser in the system directs a beam vertically. As short pulses of laser light travel through the sky, they may encounter water droplets or aerosol particles in the atmosphere. These particles intercept the laser light and scatter it in different directions. Some of the scattered light returns to Earth's surface. A receiver on the ground collects backscattered light that bounces off atmospheric particles and uses the information to determine the distance between the ground and the particles. The signals detected are collected and plotted. The greater the signal strength, the more scatterers are present in the atmosphere. A plot based on this relationship provides a ''snapshot'' of the cloud overhead and shows the structure inside the cloud. In addition, the information gathered from the MPL can be used to determine the height of the planetary boundary layer, the well-mixed layer of the atmosphere that develops during daytime hours as the sun heats Earth's surface and sets up vertical mixing. Small airborne particles that can also be detected include smoke or dust carried into the atmosphere. This information is valuable to climate researchers. Because the MPL uses an eye-safe laser, it is not a danger to ...
Date: July 10, 2001
Creator: Holdridge, D.J.

Atmospheric Radiation Measurement Program facilities newsletter, July 2000.

Description: For improved safety in and around the ARM SGP CART site, the ARM Program recently purchased and installed an aircraft detection radar system at the central facility near Lamont, Oklahoma. The new system will enhance safety measures already in place at the central facility. The SGP CART site, especially the central facility, houses several instruments employing laser technology. These instruments are designed to be eye-safe and are not a hazard to personnel at the site or pilots of low-flying aircraft over the site. However, some of the specialized equipment brought to the central facility by visiting scientists during scheduled intensive observation periods (IOPs) might use higher-power laser beams that point skyward to make measurements of clouds or aerosols in the atmosphere. If these beams were to strike the eye of a person in an aircraft flying above the instrument, damage to the person's eyesight could result. During IOPs, CART site personnel have obtained Federal Aviation Administration (FAA) approval to temporarily close the airspace directly over the central facility and keep aircraft from flying into the path of the instrument's laser beam. Information about the blocked airspace is easily transmitted to commercial aircraft, but that does not guarantee that the airspace remains completely plane-free. For this reason, during IOPs in which non-eye-safe lasers were in use in the past, ARM technicians watched for low-flying aircraft in and around the airspace over the central facility. If the technicians spotted such an aircraft, they would manually trigger a safety shutter to block the laser beam's path skyward until the plane had cleared the area.
Date: August 3, 2000
Creator: Sisterson, D. L. & Holdridge, D. J., ed.

Atmospheric Radiation Measurement Program Facilities newsletter, March 2001.

Description: The February 1998 issue of this newsletter discussed the Measurement of Pollution in the Troposphere (MOPITT) instrument that was to be tested at the SGP CART site before being launched aboard a NASA satellite to make precise, detailed measurements of tropospheric carbon monoxide and methane from space. The instrument was successfully launched on NASA's Terra satellite on December 18, 1999, by an Atlas IIAS rocket from Vandenberg Air Force Base in California and began collecting data at the end of February 2000. The instrument was designed by Dr. Jim Drummond, a physicist at the University of Toronto. The MOPITT Validation Exercise (MOVE) Campaign is schedule to take place at the SGP site from April 30 to May 18, 2001. Researchers will measure carbon monoxide by using instruments onboard the DOE Cessna Citation aircraft and other instruments located at the SGP CART. The data gathered will be compared with those collected by the MOPITT instrument to validate its performance thus far. MOPITT, which is scheduled for a five-year mission, will provide the first long-term global measurements of carbon monoxide and methane gas levels in roughly the lowest 10 miles of the atmosphere. Carbon monoxide and methane and their roles as greenhouse gases in global warming are of great interest. Greenhouse gases can trap escaping heat from Earth's surface, potentially increasing atmospheric temperatures. Carbon monoxide is a by-product of combustion, resulting primarily from industrial processing or biomass burning. Carbon monoxide levels in the atmosphere have been rising, indicating a problem. Normally, carbon monoxide is removed from the atmosphere by the hydroxyl radical, which can react with and remove many pollutants from the air.
Date: March 23, 2001
Creator: Holdridge, D.J.

Atmospheric Radiation Measurement Program facilities newsletter, May 2001.

Description: To help communities guard against the devastation that can result from severe weather, the National Weather Service (NWS) has developed a new program called StormReady. The aim is to build, at the community level, the communication and safety skills necessary to prevent loss of life and property in the event of severe weather. Each year weather-related disasters lead to 500 deaths and $14 billion in damage. The NWS hopes that prepared communities implementing StormReady can reduce these numbers when local emergency managers have clear-cut guidelines for improving their hazardous weather operations.
Date: June 1, 2001
Creator: Holdridge, D. J.

Atmospheric Radiation Measurement Program facilities newsletter, November 2000.

Description: Winter Weather Outlook--With the chill of colder temperatures in the air, we can rest assured that the icy grips of winter are just around the corner. The Climate Prediction Center (CPC), a specialized part of the National Weather Service (NWS), has issued its annual winter outlook for the 2000-2001 winter season. The CPC, located in Camp Springs, Maryland, is a government agency that focuses its predictions on Earth's climate. In comparison to the NWS forecasts of short-term weather events, the CPC goes farther into the future (from a week to seasons). The CPC conducts real-time monitoring of Earth's climate and makes predictions of climate variability over land and ocean and in the atmosphere. The CPC also evaluates the sources of major climate anomalies. The operations branch of the CPC prepares long-range forecasts by applying dynamical, empirical, and statistical techniques. The analysis branch performs applied research to identify physical factors responsible for climate fluctuations. The two branches work jointly to test new forecast methods and models, with the goal of improving model output. The CPC also evaluates the outlook for floods, droughts, hurricanes, ozone depletion, and El Nino and La Nina environments. So, what is the CPC outlook for winter 2000-2001? For the most part, winter weather will return to ''normal'' this season, because the El Nino and La Nina anomalies that shaped our past three winters have dissipated. Normal winter weather statistics are based on data for 1961-1990. The strong influence of the sea surface temperature in the tropical Pacific Ocean during an El Nino or La Nina episode, which makes it easier for forecasters to predict the trend for weather events, has given way to more neutral conditions. This winter, we should be prepared for swings in temperature and precipitation. The CPC is forecasting a more normal winter in ...
Date: December 1, 2000
Creator: Sisterson, D. L.

Atmospheric radiation measurement program facilities newsletter, March 2002.

Description: International H2O Project (IHOP-2002)--The International H2O Project (IHOP-2002) will take place in west-central Oklahoma over 44 days, May 13-June 25, 2002. The main focus will be water vapor and its role in storm development and rainfall production, information needed to improve rainfall forecasting. Forecasting the amount and location of rainfall is difficult, particularly in the warm months, and improvements are urgently needed. Accurate prediction of floods would be very beneficial to society, because flooding is costly in terms of loss of life and property damage. Deaths resulting from flash flooding outnumber those from hurricanes, tornadoes, windstorms, or lightning, and damage due to flooding exceeds $5 billion annually. One measure of weather forecasting success is the accuracy of the Quantitative Precipitation Forecast (QPF), which predicts the amount of precipitation to be received at a certain location. One of the research goals of IHOP-2002 is to determine whether more accurate, detailed measurement of humidity will improve a computer model's ability to forecast rainfall amounts accurately. Current water vapor measurements are inadequate. The weather balloons (radiosondes) that gather most of the water vapor data used in today's weather and global climate models have three problems. First, the radiosonde stations are located too far apart, generating a grid of data that is too coarse to show the needed details in water vapor variability. Second, the radiosonde launches occur only every 12 hours, again providing too few data points for a highly variable parameter. Third, the radiosonde instrument has biases and inaccuracies in its measurements. Questionable data quality and data sets too coarse in both time and space make accurate forecasting difficult. The key to better, more accurate, higher-resolution water vapor measurements is dependable, ground-based sensors that operate continually and accurately. Such sensors will decrease dependence on sparsely spaced, costly weather balloon releases. IHOP-2002 will ...
Date: April 18, 2002
Creator: Holdridge, D. J.

Atmospheric Radiation Measurement Program facilities newsletter, November 2002.

Description: Fall 2002 Intensive Operation Periods: Single Column Model and Unmanned Aerospace Vehicle--In an Intensive Operation Period (IOP) on November 3-23, 2002, researchers at the SGP CART site are collecting a detailed data set for use in improving the Single Column Model (SCM), a scaled-down climate model. The SCM represents one vertical column of air above Earth's surface and requires less computation time than a full-scale global climate model. Researchers first use the SCM to efficiently improve submodels of clouds, solar radiation transfer, and atmosphere-surface interactions, then implement the results in large-scale global models. With measured values for a starting point, the SCM predicts atmospheric variables during prescribed time periods. A computer calculates values for such quantities as the amount of solar radiation reaching the surface and predicts how clouds will evolve and interact with incoming light from the sun. Researchers compare the SCM's predictions with actual measurements made during the IOP, then adjust the submodels to make predictions more reliable. A second IOP conducted concurrently with the SCM IOP involves high-altitude, long-duration aircraft flights. The original plan was to use an unmanned aerospace vehicle (UAV), but the National Aeronautics and Space Administration (NASA) aircraft Proteus will be substituted because all UAVs have been deployed elsewhere. The UAV is a small, instrument-equipped, remote-control plane that is operated from the ground by a computer. The Proteus is a manned aircraft, originally designed to carry telecommunications relay equipment, that can be reconfigured for uses such as reconnaissance and surveillance, commercial imaging, launching of small space satellites, and atmospheric research. The plane is designed for two on-board pilots in a pressurized cabin, flying to altitudes up to 65,000 feet for as long as 18 hours. The Proteus has a variable wingspan of 77-92 feet and is 56 feet long. The plane can carry up ...
Date: December 3, 2002
Creator: Holdridge, D. J.

Atmospheric Radiation Measurement Program facilities newsletter, August 2003.

Description: This Monthly newsletter discusses the following topic: New Atmospheric Profiling Instrument Added to SGP CART Suite--A new atmospheric profiling instrument at the SGP CART site is giving researchers an additional useful data stream. The new instrument is a microwave radiometer profiler (MWRP) developed by Radiometrics Corporation.
Date: September 2, 2003
Creator: Holdridge, D.J.

Atmospheric radiation measurement program facilities newsletter, July 2002.

Description: ARM Participating in Off-site Intensive Operational Period--The ARM Program is playing a role in the Cirrus Regional Study of Tropical Anvils and Cirrus Layers-Florida Area Cirrus Experiment (CRYSTAL-FACE) intensive operational period (IOP), under way through July in South Florida. The objective of CRYSTAL-FACE is to investigate the physical properties and formation processes of tropical cirrus clouds. The ARM Program has deployed a suite of ground-based instruments in Florida for CRYSTAL-FACE. In addition, the National Aeronautics and Space Administration provides six research aircraft equipped with state-of-the-art instruments to measure characteristics of cirrus clouds and their ability to alter the temperature of the atmosphere. The reliability of climate predictions depends on the accuracy of computer models of climate. Interactions between clouds and solar radiation are a major source of current uncertainty in the models, hindering accurate climate prediction. A goal of CRYSTAL-FACE is to improve on the way clouds are represented in and integrated into the models and thus achieve more reliable climate predictions. CRYSTAL-FACE will be followed in 2004 by CRYSTAL-TWP, to be held at ARM's Tropical Western Pacific (TWP) location on Manus and Nauru Islands. New Storage Building Proposed for Central Facility--Now in the design phase is a new storage building to be erected at the central facility, west of the shipping and receiving trailer. The added storage is needed because shipping needs for the TWP are now being handled by the SGP site. New Seminole Extended Facility Location Approved--The extended facility formerly on the property of the Seminole Industrial Foundation had to be removed from service in April, after the land was sold to a new owner. Both the foundation and the new land owner offered options for new extended facility locations in the area. An Environmental Evaluation Notification Form has now been approved by the USDOE (ARM Program ...
Date: August 12, 2002
Creator: Holdridge, D. J.

Atmospheric Radiation Measurement Program facilities newsletter, December 2002.

Description: Radiometer Characterization System--The new Radiometer Characterization System (RCS) installed on the Guest Instrument Facility mezzanine at the SGP central facility will permit side-by-side evaluations of several new and modified broadband radiometers and comparisons with radiometers currently in use. If the new designs or modifications give substantially more accurate measurements, ARM scientists might elect to replace or modify the existing broadband radiometers. The RCS will also permit ARM scientists to determine whether the radiometers need cleaning more frequently than the current biweekly schedule, and an automatic radiometer washer will be evaluated for reliability and effectiveness in daily cleaning. A radiometer is an instrument used to measure radiant energy. ARM uses a pyranometer to measure the solar radiation reaching Earth's surface. Clouds, water vapor, dust, and other aerosol particles can interfere with the transmission of solar radiation. The amount of radiant energy reaching the ground depends on the type and quantity of absorbers and reflectors between the sun and Earth's surface. A pyranometer can also measure solar radiation reflected from the surface. A pyranometer has a thermoelectric device (a wire-wound, plated thermopile) that produces an electric current proportional to the broadband shortwave solar radiation reaching a detector. The detector, which is painted black, is mounted in a precision-ground glass sphere for protection from the elements. The glass must be kept very clean, because dirt and dust scatter and absorb solar radiation and make the measurement incorrect. Accurate measurements of solar radiation are needed so that scientists can accurately replicate the interactions of solar radiation and clouds in global climate models--a major goal of the ARM program. TX-2002 AIRS Validation Campaign Winding Down--The TX-2002 Atmospheric Infrared Sounder (AIRS) Validation Campaign ended on December 13, 2002. The National Aeronautics and Space Administration (NASA) conducted this intensive operations period, in which a high-altitude ER-2 aircraft ...
Date: January 9, 2003
Creator: Holdridge, D. J.