Abstract:
The Atmospheric Radiation Measurement (ARM) Program is the largest global change research program supported by the U.S. Department of Energy (DOE). ARM scientists focus on obtaining field measurements and developing models to better understand the processes that control solar and thermal infrared radiative transfer in the atmosphere (especially in clouds) and at the earth's surface.
The URL for ... the ARM Data Archive is http://www.archive.arm.gov/. The URL for general information about the ARM program is http://www.arm.gov/. The data stored by the ARM Archive includes numerous parameters about radiative flux, meteorology, water vapor and clouds.
The U.S. Southern Great Plains (SGP) site was the first field measurement site established by DOE's Atmospheric Radiation Measurement (ARM) Program. Scientists are using the information obtained from the SGP to improve cloud and radiative models and parameterizations and, thereby, the performance of atmospheric general circulation models used for climate research. Deployment of the first instrumentation to the SGP site occurred in the spring of 1992. Additional instrumentation and data processing capabilities have been incrementally added in the succeeding years. The SGP was chosen as the first ARM field measurement site for several reasons including its relatively homogenous geography and easy accessibility, wide variability of climatic and cloud conditions, surface flux properties, and large seasonal variation in temperature and specific humidity. It also already had a large, existing network of weather and climate research and instrumentation. The SGP site consists of in situ and remote-sensing instrument clusters arrayed across approximately 55,000 square miles (143,000 square kilometers) in north-central Oklahoma. The ARM SGP site is the largest and most extensive climate research field site in the world. The heart of the SGP site is the heavily instrumented Central Facility located on 160 acres of cattle pasture and wheat fields southeast of Lamont, Oklahoma. A staff of 30 scientists and technicians collect and monitor data from the Central Facility instruments and from smaller, unmanned facilities throughout the site. The instruments throughout the site automatically collect data on surface and atmospheric properties, routinely providing data to the Site Data System, which is linked by high-speed communications to the ARM Archive and Data Center. The Data Center acquires additional data from other sources, such as National Weather Service satellite and surface data, and provides tailored data packages to ARM Science Team members
The following list contains the instrumentation used for aerosols and the data available for the Central Facility at SGP.
Aerosol Observing System (AOS) For complete information on the AOS, see http://www.arm.gov/instruments/. The AOS at the Central Facility (C1; Lamont OK) is the primary ARM platform for in-situ aerosol measurements at the surface level. The AOS measures the optical properties of ambient aerosol particles in order to better understand how particles may interact with solar radiation and influence the earth's radiation balance and climate system. The system is located at the SGP site in Oklahoma and was constructed at the DOE Environmental Measurements Laboratory (EML) in New York. AOS has been operational since the beginning of April 1996. The system is currently producing aerosol data continuously; the data are ingested to a specified file format and meet ARM data processing requirements so that the data can be retrieved from the ARM Archive (http://archive.arm.gov/). The primary measurements made with the system include (1) light absorption coefficient , (2) total light scattering and hemispheric backscattering coefficients, (3) light scattering as a function of relative humidity, (4) total condensation particle concentration, (5) number concentration for particles of sizes ranging from 0.1 to 10 um, and (6) ozone concentration. The sampling interval for all AOS measurements is 1 minute; i.e., a total of 1440 data points per day if the system operates without upset that day.
At the Central Facility (C1, Lamont OK), AOS data are available for 1999-09-21 to present. ARM data streams are coded as follows: spg1aosC1: 1-min averages of many aerosol-related parameters sgp30aosC1: 30-min averages of many aerosol-related parameters Additional data streams or value added products may be added in the future.
CIMEL Sun Photometer (CSPOT) For complete information on the CSPOT, see http://www.arm.gov/instruments/. The CSPOT is a multi-channel, automatic sun-and-sky scanning radiometer that measures the direct solar irradiance and sky radiance at the Earth's surface. Measurements are taken at pre-determined discrete wavelengths in the visible and near-IR parts of the spectrum to determine atmospheric transmission and scattering properties. This instrument is weather-proof and requires little maintenance during periods of adverse weather conditions. It takes measurements only during daylight hours (sun above horizon). Atmospheric transmission is measured from the direct-normal solar irradiance measurement (sunphotometric operation). Vertical aerosol optical thickness is derived to an accuracy of +/- 0.02 - 0.04 at an airmass of 2. Water vapor column abundance is measured to an accuracy of +/- 10 percent. Aerosol size distribution in the 0.1 to 3 micron size range is derived from the sky radiance measurements (radiometric operation) using radiative transfer algorithms. Phase function is obtained from the size distribution. The accuracy of the latter derived products is unknown.
At the Central Facility (C1, Lamont OK), CSPOT data are available for 1994-04-06 to present. ARM data streams are coded as shown. Please note the X1 in the data stream code rather than the typical C1. In this case, the X denotes that the data stream is collected by an external vendor. sgpcsphotX1: Cimel Sunphotometer (CSPOT): aerosol optical thickness data sgpcsphotalmX1: Cimel Sunphotometer (CSPOT): almucantars sky radiance data sgpcsphotfiltX1: Cimel Sunphotometer (CSPOT): aerosol optical thickness, filtered data sgpcsphotppX1: Cimel Sunphotometer (CSPOT): principal planes data sgpcsphotsizeX1: Derived: aerosol size distributions from CSPOT
Multi-Filter Rotating Shadowband Radiometer (MFRSR). For complete information on the MFRSR, see http://www.arm.gov/instruments/. The MFRSR takes spectral measurements of direct normal, diffuse horizontal, and total horizontal solar irradiances. These measurements are at nominal wavelengths of 415, 500, 615, 673, 870, and 940 nm. The measurements are made at a user specified time interval, typically about one minute or less. At the SGP site, the sampling interval is 20 seconds. From such measurements, one may infer the atmosphere's optical depth at the wavelengths mentioned above. In turn, these optical depths may be used to derive information about the column abundances of ozone and water vapor, as well as aerosol and other atmospheric constituents. A silicon detector is also part of the MFRSR. This broadband detector provides a measure of the broadband direct normal, diffuse horizontal, and total horizontal solar irradiances. These quantities are uncalibrated and reported in units of counts. An MFRSR head that is mounted to look vertically downward can measure upwelling spectral irradiances (at the same wavelengths as the MFRSR). In the ARM system, this instrument is called an MFR. At the SGP there are two MFRs; one mounted at the 10 m height and the other at 25 m. At the NSA sites, the MFRs are mounted at 10 m. The primary quantities measured by the system are: (1) the direct normal solar spectral irradiance, (2) the total horizontal solar spectral irradiance, and (3) the diffuse horizontal solar spectral irradiance. The measurements at each wavelength are made by a single filtered detector with a nominal 10-nm FWHM bandwidth.
MFR data at the Central Facility (C1; Lamont OK) are available for 1997-01-08 to present. ARM data streams are coded as follows: sgpmfr10m: MFR: upwelling radiance at 10-meter height sgpmfr25m: MFR: upwelling radiance at 25-meter height sgpmfrirt10m: Infrared Thermometer (MFRIRT): upwelling radiance, averaged 60-sec at 10-meter height sgpmfirt25m: Infrared Thermometer (MFRIRT): upwelling radiance, instantaneous 20-sec at 25-meter height sgpmfrsr: MFRSR: irradiances Additional data streams or value added products may be added in the future
Raman Lidar (RL). For a complete description of the RL, visit http://www.arm.gov/instruments/. The RL is an active, ground-based laser remote sensing instrument that measures vertical profiles of water-vapor mixing ratio and several cloud- and aerosol-related quantities. Lidar (light detection and ranging) is the optical analog of radar, using pulses of laser radiation to probe the atmosphere. This system is fully computer automated, and will run unattended for many days following a brief (~5-minute) startup period. The self-contained system (requiring only external electrical power) is housed in a climate-controlled 8ft x 8ft x 20ft standard shipping container.
The Raman Lidar has independent measurement channels that record range-resolved backscatter signals from molecular water vapor, molecular nitrogen, and combined Rayleigh and aerosol contributions (the latter at polarizations parallel and perpendicular to the polarization of the laser beam). Primary quantities obtained from these backscatter signals are range-resolved vertical profiles of water-vapor mixing ratio (g/kg), aerosol scattering ratio (unitless), and backscatter depolarization ratio (percent). Additional cloud- and aerosol-related measurements can also be derived from the backscatter signals.
RL data are available for the Central Facility (C1; Lamont OK) from 1996-06-03 to present. ARM data streams are coded as follows: sgprlC1: raw backscattered profiles at 355, 387, and 408 nm sgprllogC1: surface log information sgp30rlprofC1: derived 30-min RL profiles-water vapor mixing, aerosols, scattering and depol. sgp10rlprofC1: derived 10-min profiles of water vapor mixing, aerosols, scattering and depol. sgp10rlprofasr1ferrC1: aerosol extinction profiles and aerosol optical thickness sgp10rlprofbe1turnC1: best-estimate state of the atmosphere product from the RL and AERI (atmospheric emitted radiance interferometer) + GOES (geostationary operational environmental satellite) retrievals sgp10rlprofdep1turnC1: depolarization profiles and single layer cloud optical depths sgp10rlprofmrlturnC1: water vapor mixing ratio and relative humidity profiles, along with precipitable water vapor sgp10rlprofext1ferrC1: aerosol extinction profiles and aerosol optical thickness from the RL Additional data streams or value added products may be added in the future.
Description:
This catalog lists the data streams that are currently available from the ARM Archive. The data streams are listed by file format type (i.e, CDF, HDF, RAW, JPG, ASC, and Other) and then by the site where the data are collected. Each list contains the name of the data streams in alphanumeric order, the number of files within the data stream, the minimum data date, and the maximum data date. The sites that have the word development in parenthesis are data processes which are operated during the final phases of implementation of a data source, resulting in data which are labeled as Development. Development data are frequently available to users, but additional information about the operating conditions and potential for errors must be considered. The files in CDF format are also listed in preformatted lists for those browsers that have difficulty handling large html tables. The information in this catalog is updated about once a month.
Quality
One of the goals of the ARM Program is to provide data streams of reasonable quality for scientific research. Traditionally, data quality issues have been addressed within ARM at several levels, including by instrument mentors, site scientists, value added product scientists, and Science Team members at large. Maintaining data quality for a program of the size and ... complexity of ARM is a significant challenge. Efforts toward this end have matured and evolved over the life of the program. The ARM Program Data Quality (DQ) Office has the responsibility for ensuring that quality assurance results are communicated to (1) data users so that they may make informed decisions when using the data, and (2) ARM's Site Operations and Engineers to facilitate improved instrument performance and thereby minimize the amount of unacceptable data collected. For additional information, visit http://www.arm.gov/data/data_quality.stm.
Access Constraints
Data of common interest from external sources are shared whenever possible, but some sources restrict secondary distribution of data. In these cases, ARM will seek specific allowances to distribute such data to members of the ARM Science Team, but will observe restrictions on further distribution from the Archive if required.
Use Constraints
Use-constraints, if any, are provided in Data Quality Reports sent with the data files when data are requested. The automatic inclusion of a data originator as a co-author is not insisted upon in the ARM program, but the source of any data should be clearly recognized either as a co-author or through an appropriate acknowledgment. The ARM Program should be acknowledged ... in publications as the programmatic origin of the field program. ARM-funded investigators will use the following acknowledgment: "This research was supported by the Office of Biological and Environmental Research of the U.S. Department of Energy (under grant or contract number - if appropriate) as part of the Atmospheric Radiation Measurement Program." The U.S. Department of Energy's Atmospheric Radiation Measurement Program should be appropriately acknowledged in publications resulting from collaborative efforts in which ARM data or facilities were used. ARM-funded principal investigators will give proper acknowledgment to cooperating or collaborating programs in those cases where data originating therein are being used.
Distribution_Media:
FTP or request
Distribution_Size:
Variable
Distribution_Format:
netCDF
Fees:
None
Personnel
JAMES
C
LILJEGREN Role:
TECHNICAL CONTACT
Phone:
(630) 252-9540
Fax:
(630) 252-9792
Email:
liljegren at anl.gov
Contact Address:
Argonne National Laboratory
ER Division, Bldg. 203
9700 South Cass Ave. City:
Argonne
Province or State:
IL
Postal Code:
60439
Country:
USA
PETER
J
LAMB Role:
INVESTIGATOR
Phone:
(405) 325-3041
Fax:
(405) 325-7614
Email:
plamb at ou.edu
Contact Address:
University of Oklahoma
CIMMS Department
100 E. Boyd, Rm. 1110 City:
Norman
Province or State:
OK
Postal Code:
73019
Country:
USA
RAYMOND
MCCORD Role:
DIF AUTHOR
Phone:
865-574-7827
Fax:
865-574-4665
Email:
mccordra at ornl.gov
Contact Address:
Building 1507, MS 6407
P.O. Box 2008
Oak Ridge National Laboratory City:
Oak Ridge
Province or State:
TN
Postal Code:
37831-6407
Country:
USA
Publications/References
Ackerman, T. P. and G. M. Stokes. 2003. The Atmospheric Radiation Measurement Program. Physics Today 56: 38-44. Science Plan for the Atmospheric Radiation Measurement Program (ARM). 1996. U.S. Department of Energy, DOE/ER-0670T. Atmospheric Radiation Measurement Program Plan. 1990. DOE/ER-0441. U.S. Department of Energy, Office of Energy Research, Washington, D.C. NTIS DE90008108.
Links
