For more than sixty years the Department of Meteorology has encouraged the development of special sensors and measurement systems to support diverse theoretical studies and observational programs. Today instruments sited at the Larson Agricultural Research Center near Rock Springs, near Scotia in the Pennsylvania State Game Lands (#176), and at Walker Building provide essentially continuous measurements of state parameters, winds, turbulence, radiation, sky cover, air quality, precipitation chemistry, various profiles, etc. Some of the continuously operating systems include an ASOS (Automated Surface Observing System) donated to the department by Systems Management Incorporated; a SURFace RADiation system installed by the National Oceanic and Atmospheric Administration (NOAA);, a NOAA/CORE system for air quality monitoring; numerous precipitation and deposition samplers; and a single-station lightning locator. In addition, Dr. Ken Davis and researchers with the Chequamegon Ecosystem-Atmosphere Study maintain field stations in Wisconsin and Michigan which continuously measure the fluxes of carbon dioxide, momentum, heat and water vapor between the forest and the atmosphere.
Specialized sensors that are operated intermittently for graduate and faculty research projects include radar and radiometric profilers, mmWave (94 GHz) Doppler radars, multichannel microwave radiometers, multiple sonic anemometers, acoustic sounders (sodars), a diverse set of laser-based sensors for gas and particle measurements, etc.
Cloud Structure
and Radiation
Laboratory for
Cloud and Aerosol Experimentation
Air and Precipitation
Chemistry
Surface
Radiation System
Soil
Climate Analysis Network
Automated
Surface Observing System (ASOS)
Scotia
Atmospheric Chemistry Site
Penn State
GP-1 Lightning Locator
ChEAS Field Sites
Real-time
precipitatioin conductivity measurements on the roof of Walker Bldg.
Cloud Structure and Radiation
The Department has exceptional capability in the area of ground-based remote sensing of clouds. In addition to the microwave radiometer, the Department has available two 94-GHz cloud radars, a small lidar system, a Vaisala ceilometer, a 10-µm radiometer, several sets of broad-band solar and infrared radiometers, a sun photometer, and an all-sky camera. The cloud radar is a unique instrument capable of sampling multiple cloud layers and detecting both cloud and precipitation droplets. The Doppler spectral measurements can be used to retrieve cloud particle size distributions in both stratus and cirrus clouds. The high temporal and spatial resolution inherent in the 94-GHz system permit detailed studies of cloud structure. This suite of instruments is being used to obtain an ongoing data set to study cloud formation and maintenance, as well as the impact of clouds on the surface radiation balance. Additional insight is gained into the question of cloud lifecycle by linking the observations to dynamical simulations using the PSU/NCAR mesoscale model.Laboratory for Cloud and Aerosol Experimentation
The laboratory proves to be an ideal place in which to investigate some of the important microscale phenomena that contribute to the formation and properties of clouds and aerosols. The Department's 1400-ft2 laboratory space is well equipped with pure water and air facilities, fume hoods, a clean bench, sample refrigerator, several freezers, and a high-capacity vacuum line. As needed, additional equipment is developed and used to conduct specific experiments, such as those designed to study the growth of cirrus-like ice crystals, to investigate the nucleating capabilities of aerosol particles, to measure the rates with which aerosol particles and trace gases are taken up by snow, and to explore the interactions of ambient moisture and nitric acid vapor with representative aerosol particles. The results from the laboratory experimentation find application in a variety of physical and chemical models of atmospheric clouds and aerosols.Air and Precipitation Chemistry
The Department conducts air chemistry research in regional air quality, the atmospheric effects of aircraft, and chemistry's role in global change. These efforts involve developing state-of-the-art sensors for reactive trace gases, field observations using these sensors, and analysis with computer models of atmospheric chemistry and dynamics. A sensor for the hydroxyl (OH) and hydroperoxyl (HO2) reactive gases was developed and deployed on the NASA DC-8 aircraft for the NASA SUCCESS mission (Kansas-Oklahoma, 1996) and on the NASA SONEX (North Atlantic, 1997) field project. It will also be deployed on the NASA DC-8 aircraft for the PEM Tropics mission over the Central Pacific in early 1999. The sensor can be reconfigured for ground-based and tower-based measurements at the Department's Rock Springs site and other sites around the country. It has been used in summer 1998 as part of PROPHET, a multi-investigator tower-based study at the University of Michigan Biological Station. Sensors for other important reactive gases, such as nitrogen dioxide (NO2), are also being developed. These sensors and sensors for other gases, micrometeorology, and radiation are being used to study the interaction of chemistry and dynamics in the planetary boundary layer and the remote troposphere.In-situ measurements of turbulence,
micrometeorological, air pollution and acidic deposition variables are
performed routinely at the Larson Agricultural Research Center Farm and
the Scotia Atmospheric Chemistry
site. The acidic precipitation data, which have been gathered since
1976 at the Scotia site, provide one of the longest records in the country.
Research and development groups from several national and international
laboratories come to these field sites for calibrating and checking the
performance of their diverse measurement systems. In addition, various
aspects of cloud physics and chemistry are investigated in the laboratory
to help interpret these field measurements.
Surface
Radiation System
The National
Oceanic and Atmospheric Administration has installed an automated
system (SURFRAD) for measuring radiation parameters at seven sites
in the United States. One of these sites is at LARC near Rock Springs
west of the Penn State Campus.
Soil
Climate Analysis Network
USDA has installed a station
in their Soil Climate Analysis Network at Rock Springs. This measures
weather and soil parameters. Current data are available.
Automated
Surface Observing System (ASOS)
In 1998, Systems
Management Incorporated donated a remote ASOS
to the department. The system monitors meteorological variables such as
wind speed and direction, barometric pressure, temperature and dewpoint,
accumulated precipitation, precipitation type and the height of the cloud
base. Lightning and freezing rain sensors are also included.
Scotia Atmospheric Chemistry Site
This rural site, located on Pennsylvania State Game Lands Tract No. 176 in the middle of a broad valley, is used for the routine collection of precipitation and ambient air samples. Site instrumentation consists of a number of precipitation gauges, wet-only collectors, some meteorological sensors, and monitors for the continuous measurement of ambient sulfate and sulfur dioxide. Over its more than twenty years of operation, this site has been used to collocate collectors from several different federal and state agencies in the United States and Canada for the purpose of intercomparing protocols and data. Long-term records of the type generated at the Scotia site demonstrate that the chemical quality of precipitation responds both to changes in the emissions of primary pollutants by industry and to a variety of meteorological factors.Penn State GP-1 Lightning Locator
The Meteorology Department has been given a single-station lightning locating system, the GP-1 (Great Plains-1), that was designed, built, and set up by Hampton W. Shirer, Professor Emeritus of the University of Kansas in Lawrence, Kansas. This design is based on the published gated, wide-band direction finding method of Philip Krider, Carl Noggle, and Martin Uman. The antenna for the GP-1 system is installed on the top of Walker Building, and the estimated location of lightning activity within approximately 500 km is displayed in the Weather Station. The estimated locations are obtained via statistical analysis of the received electromagnetic signals; calibration and improvement of the method for doing so are topics of ongoing research. The Web site provides a description of the GP-1 system, together with a set of instructions for building and testing a system. A planned addition to the Web site is a display of the current locations of lightning activity within 500 km of University Park, as estimated by the Department's GP-1.
Dr. Ken Davis and researchers with the Chequamegon Ecosystem-Atmosphere Study (ChEAS) maintain a set of field stations in northern Wisconsin and the upper peninsula of Michigan. Four towers across the area, including one that is 450 m tall, are used to continuously measure the fluxes of carbon dioxide, momentum, heat and water vapor between the forest and the atmosphere. The group also maintains a number of micrometeorology observation stations, and conducts measurements of sapflow, leaf gas exchange, and soil respiration.
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