ARM Tropical Western Pacific, Darwin Site, Cloud Measurements

Federal Geographic Data Committee (FGDC) Metadata:


Identification_Information:
Citation:
Citation_Information:
Originator: Wanda Ferrell, Ted Cress, Thomas Ackerman
Publication_Date: Unknown
Title: ARM Tropical Western Pacific, Darwin Site, Cloud Measurements
Edition:
Geospatial_Data_Presentation_Form: netCDF files
Series_Information:
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Online_Linkage: http://www.arm.gov
Description:
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 Tropical Western Pacific (TWP) locale was the second measurement facility implemented by the U.S. Department of Energy's (DOE's) Atmospheric Radiation Measurement (ARM) Program. TWP began phased operations in 1996 at its first facility on Manus Island. The second facility on Nauru Island was implemented in 1998. In 2002, a third facility in Darwin, Australia was completed to support the first two sites. The availability of data from Darwin is subject to interruption when instruments or parts are needed to repair Manus or Nauru. Data from these sites will be used by scientists to study the effects of this region on the global climate. The TWP locale is the area roughly between 10 degrees N to 10 degrees S of the equator from Indonesia to near Christmas Island. This region of the world plays a large role in the interannual variability observed in the global climate system. For instance, the El Nino/Southern Oscillation phenomenon has far-reaching implications for weather patterns over much of the Northern Hemisphere, and perhaps the entire planet. The TWP consistently has the warmest sea surface temperatures on the planet and is referred to as the Pacific warm pool. The warm pool supplies heat and moisture to the atmosphere above it, resulting in the formation of deep convective cloud systems, which in turn produce high-altitude cirrus clouds that spread out over much of the region. These cloud systems regulate the amount of solar energy reaching the surface of the earth and the amount of the earth's heat energy that can escape to space. Improved understanding of the interaction between clouds and incoming and outgoing energy will improve the general circulation models used for climate research. Cloud measurements from Darwin use many specialized instruments. Detailed information on each instrument is available at "http://www.arm.gov/instruments/". The following list contains the instrumentation used for cloud measurements and the data available for the Darwin site. Vaisala Ceilometer (VCEIL). For complete VCEIL information, visit "http://www.arm.gov/instruments/". The VCEIL is a self-contained, ground-based, active, remote-sensing device designed to measure cloud-base height at up to three levels and potential backscatter signals by aerosols. Model CT25K has a maximum vertical range of 25,000 feet. The ceilometer transmits near-infrared pulses of light, and the receiver telescope detects the light scattered back by clouds and precipitation. The Vaisala ceilometers measure the backscattered light intensity from a pulsed InGaAs diode laser (905 nm) as a function of distance (15-m resolution of the CT25K). These measurements are used to produce derived products that are recorded. These products include (1) backscatter profile with 15-m resolution; (2) cloud-bottom height determined with an algorithm to define cloud bottom as the height corresponding to a visibility reduction to 100 m; (3) secondary cloud-bottom heights from a cloud above the lowest cloud; and (4) tertiary cloud-bottom heights from an even higher cloud. At Darwin (C3), VCEIL data are available for 2002-02-27 to present. ARM data stream is coded as follows: twpvceil25kC3: cloud base heights, 25,000 feet maximum range Additional data streams or value added products may be added in the future. Millimeter Wave Cloud Radar (MMCR). For complete MMCR information, visit "http://www.arm.gov/instruments/". The MMCR systems probe the extent and composition of clouds at millimeter wavelengths. The MMCR is a zenith-pointing radar that operates at a frequency of 35 GHz. The main purpose of this radar is to determine cloud boundaries (e.g., cloud bottoms and tops). This radar will also report radar reflectivity (dBZ) of the atmosphere up to 20 km. The radar possesses a doppler capability that will allow the measurement of cloud constituent vertical velocities. The primary quantities measured with this system are (1) radar doppler spectra, (2) radar doppler moments, (3) radar reflectivity (dBZ), (4) vertical velocity, and (5) spectral width. Inversions are in development to infer cloud microphysical properties. At Darwin (C3), MMCR data are available from 2002-03-06 to present. ARM data streams are coded as follows: twpmmcrcalC3: calibration data twpmmcrmomentsC3: moments data twpmmcrmonC3: moments data twpmmcrpowC3: power data Additional data streams or value added products may be added in the future. Micropulse Lidar (MPL). For complete MPL information, visit "http://www.arm.gov/instruments/". The MPL is a ground-based optical remote sensing system designed primarily to determine the altitude of clouds overhead and provides information on cloud base (thick clouds), cloud base and top (optically thin clouds) and an aerosol profile. The physical principle is the same as for radar. A pulse of energy is transmitted and the energy reflected back is measured. From the time delay between the transmitted pulse and the backscattered signal, the distance to the scatterer is infered. Besides real-time detection of clouds, post-processing can also characterize the extent of the tropospheric mixing layer (the planetary boundary layer), or other particle-laden regions. This eye-safe system is designed for continuous operation. The MPL has one measurement channel that records backscatter signals in 300 meter range bins, with the lowest valid range bin beginning at 120 meters above ground level, up to 20 kilometers. The primary quantity obtained from this signal is the real-time reporting of the lowest detected cloud base in meters, obtained from 60 sec averages. Additional quantities possible through post-processing of the raw signal return include a relative backscatter profile (counts/sec/meter) with instrument effects removed. Instrument effects include a dead-time correction specific to the individual detector, near-range corrections for the overlap of the transmitting and detection optics, and removal of afterpulsing due to detector saturation from optical crosstalk as the pulse is transmitted. From the relative backscatter profile, other data products are possible. These include cloud boundaries, multiple cloud decks, and layer boundaries. At Darwin (C3), MPL data are available from 2002-08-08 to present. ARM data stream is coded as follows: twpmplC3: cloud base and top heights. Additional data streams or value added products may be added in the future. Microwave Radiometer (MWR). For complete MWR information, see "http://www.arm.gov/instruments/". The MWR provides time-series measurements of column-integrated amounts of water vapor and liquid water. The instrument itself is essentially a sensitive microwave receiver. That is, it is tuned to measure the microwave emissions of the vapor and liquid water molecules in the atmosphere at specific frequencies. The MWR receives microwave radiation from the sky at 23.8 GHz and 31.4 GHz. These two frequencies allow simultaneous determination of water vapor and liquid water burdens along a selected path. Atmospheric water vapor observations are made at the hinge point of the emission line where the vapor emission does not change with altitude (pressure). Cloud liquid in the atmosphere emits in a continuum that increases with frequency, dominating the 31.4 GHz observation, whereas water vapor dominates the 23.8-GHz channel. The water vapor and liquid water signals can, therefore, be separated by observing at these two frequencies. At Darwin, Australia (C3) MWR data is available for 2002-02-27 to present. ARM data streams are coded as follows: twpmwrlosC3: water liquid and vapor along line of sight path twpmwrtipC3: airmasses, brightness temperatures in TIP mode. Additional data streams or value added products may be added in the future. Whole-Sky Imager (WSI). For complete information on the WSI, see "http://www.arm.gov/instruments/". The WSI is an automated imager used for assessing and documenting cloud fields and cloud field dynamics. The WSI is a ground-based electronic imaging system that monitors the upper hemisphere. It is a passive, i.e., non-emissive, system that acquires images of the sky dome through three spectral filters (neutral, red, and blue). From these sky images, we can assess the presence, distribution, shape, and radiance of clouds over the entire sky using automated cloud decision algorithms and related processing. The current WSI model (EO System 6) is capable of image acquisition under daylight, moonlight, and starlight conditions. The WSI measures the sky radiance in approximately 1/3 degree increments over the entire sky dome. The measurements are made in two narrow spectral regions centered at 650 nm and 450 nm. The sky radiances are acquired as two 16-bit images and are used to determine the presence of opaque clouds and thin clouds in the line of sight on a pixel-by-pixel basis. These cloud data are used to calculate the cloud cover and statistical quantities. At Darwin (C3), WSI data are available for 2002-03-06 to present. ARM data streams are coded as follows: twpwsicloudC3: Derived: cloud numbers, area, perimeter, and more from the WSI twpwsicloudsummaryC3: cloud and aerosol information, classification summary data twpwsifullradianceC3: calibrated radiances for each pixel, with multiple filters twpwsipatchsummaryC3: radiances from red image for three patches (average and standard deviation) Additional data streams or value added products may be added in the future. Total Sky Imager (TSI). For complete TSI information, visit "http://www.arm.gov/instruments/". The TSI provides time series of hemispheric sky images during daylight hours, and retrievals of fractional sky cover for periods when the solar elevation is greater than 5 to 10 degrees. The primary quantities measured are visual record of sky conditions, fractional sky cover (clear, thin, and opaque amounts), and sun obscuration by cloud (sunshine meter). At Darwin (C3), TSI data are available from 1996-10-11 to present. ARM data stream is coded as follows: twptsiskycoverC3: TSI sky cover Additional data streams or value added products may be added in the future.
Purpose:
Not Available
Supplemental_Information:
REFERENCE: 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.
Time_Period_of_Content:
Time_Period_Information:
Range_of_Dates/Times:
Beginning_Date: 20020227
Ending_Date: Unknown
Currentness_Reference:Unknown
Status:
Progress: Complete
Maintenance_and_Update_Frequency: As needed
Spatial_Domain:
Description_of_Geographic_Extent:
Bounding_Coordinates:
West_Bounding_Coordinate: 130.891
East_Bounding_Coordinate: 130.891
North_Bounding_Coordinate: -12.425
South_Bounding_Coordinate: -12.425
Keywords:
Theme:
Theme_Keyword_Thesaurus: GCMD SCIENCE PARAMETERS
Theme_Keyword_Thesaurus: GCMD INSTRUMENT
Theme_Keyword_Thesaurus: PROJECT
Theme_Keyword_Thesaurus: ANCILLARY KEYWORDS
Theme_Keyword_Thesaurus: ISO TOPIC CATEGORY
Theme_Keyword_Thesaurus: DATA SET LANGUAGE
Theme_Keyword: EARTH SCIENCE > ATMOSPHERE > ATMOSPHERIC WATER VAPOR > WATER VAPOR PROFILES
Theme_Keyword: EARTH SCIENCE > ATMOSPHERE > CLOUDS > CLOUD PROPERTIES > CLOUD FREQUENCY
Theme_Keyword: EARTH SCIENCE > ATMOSPHERE > CLOUDS > CLOUD PROPERTIES > CLOUD CEILING
Theme_Keyword: EARTH SCIENCE > ATMOSPHERE > CLOUDS > CLOUD PROPERTIES > CLOUD HEIGHT
Theme_Keyword: EARTH SCIENCE > ATMOSPHERE > CLOUDS > CLOUD MICROPHYSICS > CLOUD LIQUID WATER/ICE
Theme_Keyword: EARTH SCIENCE > ATMOSPHERE > CLOUDS > CLOUD PROPERTIES > CLOUD VERTICAL DISTRIBUTION
Theme_Keyword: EARTH SCIENCE > ATMOSPHERE > CLOUDS > CLOUD PROPERTIES > CLOUD BASE HEIGHT
Theme_Keyword: ASC > ALL-SKY CAMERA
Theme_Keyword: CCD IMAGER
Theme_Keyword: CLS > CLOUD LIDAR SYSTEM
Theme_Keyword: CEILOMETERS
Theme_Keyword: CRS > CLOUD RADAR SYSTEM
Theme_Keyword: MWR > MICROWAVE WATER RADIOMETER
Theme_Keyword: ARM > ATMOSPHERIC RADIATION MEASUREMENT PROJECT
Theme_Keyword: Doe
Theme_Keyword: Department Of Energy
Theme_Keyword: Climate Change
Theme_Keyword: Global Change
Theme_Keyword: CLIMATOLOGY/METEOROLOGY/ATMOSPHERE
Theme_Keyword: ENGLISH
Place:
Place_Keyword_Thesaurus: GCMD
Place_Keyword: CONTINENT > AUSTRALIA/NEW ZEALAND > AUSTRALIA > DARWIN, DARWIN INTERNATIONAL AIRPORT, ARM TWP SITE C3
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.
Point_of_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: LARRY JONES
Contact_Position: TECHNICAL CONTACT
Contact_Address:
Address_Type: Mailing and Physical Address
Address: Tropical Western Pacific Project Office
Address: Los Alamos National Laboratory
Address: P.O. Box 1663, MSJ577, TA-51, Bldg. 82
City: Los Alamos
State_or_Province: NM
Postal_Code: 87545
Country: USA
Contact_Voice_Telephone: (505) 667-1186
Contact_Facsimile_Telephone: (505) 667-9122
Contact_Electronic_Mail_Address: ljones@lanl.gov
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Data_Quality_Information:
Attribute_Accuracy:
Attribute_Accuracy_Report:
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".
Logical_Consistency_Report:
Not Available
Completeness_Report:
Not Available
Lineage:
Process_Step:
Process_Description:
Not Available
Process_Date: Unknown
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Spatial_Reference_Information:
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Distribution_Information:
Distributor:
Contact_Information:
Contact_Organization_Primary:
Contact_Organization: DOE/ARM/ARCHIVE > ARM Archive, Atmospheric Radiation Measurement Program, U. S. Department of Energy
Contact_Person: ARM USER SERVICES
Contact_Position: DATA CENTER CONTACT
Contact_Address:
Address_Type: Mailing and Physical Address
Address: Oak Ridge National Laboratory
Address: Building 1507, MS 6407
Address: P.O. Box 2008
City: Oak Ridge
State_or_Province: TN
Postal_Code: 37831-6407
Country: USA
Contact_Voice_Telephone: 888-ARM-DATA (888-276-3282) or 865-241-4851
Contact_Facsimile_Telephone: 865-574-4665
Contact_Electronic_Mail_Address: armarchive@ornl.gov
Resource_Description: TWPC3cloud
Distribution_Liability:
Not Available
Standard_Order_Process:
Digital_Form:
Digital_Transfer_Information:
Format_Name: netCDF
Transfer_Size: Variable
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name:
http://www.archive.arm.gov
Access_Instructions:
DATA CENTER URL
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name:
http://gcmd.nasa.gov/getserf.htm?NCVweb
Access_Instructions:
NCVweb is an interactive web-based tool for viewing atmospheric radiation measurement (ARM) data.
Digital_Transfer_Option:
Online_Option:
Computer_Contact_Information:
Network_Address:
Network_Resource_Name:
http://www.archive.arm.gov/docs/catalog/
Access_Instructions:
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.
Fees: None
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Metadata_Reference_Information:
Metadata_Date: 20030930
Metadata_Review_Date: 20060202
Metadata_Contact:
Contact_Information:
Contact_Person_Primary:
Contact_Person: RAYMOND MCCORD
Contact_Position: DIF AUTHOR
Contact_Address:
Address_Type: Mailing and Physical Address
Address: Building 1507, MS 6407
Address: P.O. Box 2008
Address: Oak Ridge National Laboratory
City: Oak Ridge
State_or_Province: TN
Postal_Code: 37831-6407
Country: USA
Contact_Voice_Telephone: 865-574-7827
Contact_Facsimile_Telephone: 865-574-4665
Contact_Electronic_Mail_Address: mccordra@ornl.gov
Metadata_Standard_Name: FGDC Content Standards for Digital Geospatial Metadata
Metadata_Standard_Version: FGDC-STD-001-1998
Metadata_Time_Convention: local time
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