The phenomena studied were the daytime convective boundary layer structure and physical processes. This study used airborne measurement of vertical and horizontal wind gusts, humidity, potential temperature, mean horizontal wind speed, and horizontal linear trends of temperature, humidity, radiation. Fluxes of sensible heat, moisture, and momentum were estimated from fast response wind gust, temperature, and humidity measurements; these fluxes were evaluated from data with the arithmetic means removed. In addition several radiation parameters were also measured.. Several radiation parameters were also measured (e.g., global short and longwave, upwelling, and downwelling). Altitude of the aircraft was measured by radar and pressure; radar was more accurate but was only valid below about 930 m. Geographical position was measured by an inertial navigation system. All level legs of a flight mission were flown at a constant pressure altitude, thus the altitude of the aircraft over the surface varied.
In general, the data set is of excellent overall quality with very little loss of data. Vertical winds were sampled at an effective rate of 5 samples per second instead of the customary 10 samples per second; this had negligible effect on the fluxes but could compromise estimates of turbulence dissipation. Fluxes were estimated using raw, detrended and high-pass filtered data. From extensive analysis the FIFE Boundary Layer Group recommends using the detrended data.
Aircraft Flux - Raw: Univ. of Col. (FIFE)
(Raw Atmospheric Turbulence Data from the NCAR King Air).
The Raw Atmospheric Turbulence Data from the NCAR King Air data set contains fluxes of sensible heat, moisture, and momentum estimated from fast response wind gust, temperature, and humidity measurements. These data used untreated time histories (i.e., raw data) in the derivation of fluxes using the eddy correlation technique.
The NCAR King Air participation in FIFE-1987 and FIFE-1989 was part of a coordinated atmospheric boundary layer component which included other aircraft (Univ. Wyoming King Air and National Research Council of Canada (NRC) Twin Otter), surface measurements, balloon-borne profiles, and SODAR and lidar remote sensing. The chief objective of the boundary layer component was to describe the structure of the atmospheric boundary layer over the FIFE study area, increase knowledge of the physical processes active in the daytime boundary layer, and explore the relationship of surface properties to the time and spatial variation in the structure of the boundary layer.
The phenomena studied were the daytime convective boundary layer structure and physical processes. The study used airborne measurement of vertical and horizontal wind gusts, humidity, potential temperature, mean horizontal wind speed, and horizontal linear trends of temperature, humidity, radiation. Fluxes of sensible heat, moisture, and momentum were estimated from fast response wind gust, temperature, and humidity measurements; these fluxes were evaluated from raw data (i.e., RAW). The following radiation parameters were also measured: Global short and longwave; 2 degree field-of-view, 8-12 micrometer, upwelling (apparent surface temperature at lowest altitude flown) and downwelling longwave; a measure of surface greenness (vegetation). Altitude of the aircraft was measured by radar and pressure; radar was more accurate but was only valid below about 930 m. Geographical position was measured by an inertial navigation system. It is important to mention that all level legs of a flight mission were flown at a constant pressure altitude, thus the altitude of the aircraft over the surface varied.
It should be noted that in the final submission to the FIS, three sets of flux and RMS data were submitted. The first used untreated time histories in the derivation of fluxes using the eddy correlation technique (RAW), the second used linearly detrended data (DETREND), the third used time histories that were high-pass filtered (FILTERED) with a third order algorithm with a break point set at 0.012 Hz (5 km wavelength). It is felt that most scientists working with the flux and correlation coefficient data, would prefer to use the linearly detrended data. Data from the NAE (Canada) Twin Otter and University of Wyoming King Air aircraft were archived with the identical formats.
The NCAR King Air participation in FIFE was during IFC-1 (Early part of growing season, 1987) and IFC-5 (the 1989 return to the Konza to capture a dry down situation and apply lessons learned from the 1987 experience).
In IFC-1 the King Air worked alone. As it was the first aircraft to visit the FIFE study area various mission profiles were explored.
Initially, adequacy of the 15 km run length was investigated by extending runs 15 km to the east of the FIFE study area where the surface was more similar to that over the FIFE study area than to the west. Other missions included various attempts at flux profiles using L-patterns where the aircraft flew along the north and east sides of the FIFE study area. The so-called Golden Day mission, 6 June 1987, was designed to investigate the time variation of the fluxes near the surface and inversion layers by flying repeatedly along the north side of the FIFE study area between 490 m pressure altitude (~30 m above the highest point along the track) and about 50 m below the inversion level (which varied with time). For both IFC's the aircraft was based at Salina, Kansas. In 1987 the ferry to the FIFE study area was used to obtain inbound vertical profiles of wind, temperature, humidity, and aerosol from approximately 3000 m to near the surface. However, one mission explored the regional variation of fluxes by flying about 100 km to the northeast of the FIFE study area.
In general data quality for IFC-1 is very good. Vertical winds were sampled at an effective rate of 5 samples per second instead of the customary 10 samples per second; this had negligible effect on the fluxes but could compromise estimates of turbulence dissipation. A full data quality report is given in the Known Problems with the Data Section.
In IFC-5 the NCAR King Air worked in consort with the NRC Twin Otter. During this IFC emphasis was on time and space variation of atmospheric budgets, spatial variation of fluxes over the FIFE study area, and regional variation. The NCAR King Air concentrated on time variation of convective boundary layer budgets and their regional variation. The budget missions were "time centered" so that the average time-of-day was constant for all pairs of legs flown at the same level. Regional variation was explored by always flying the ferry flight from Salina to the FIFE study area at 500 m pressure altitude. Time variation was explored by coordinated missions with the Twin Otter having the same objective and flight plan; these occurred on 27 July, and 2,4,6,7 August 1989.
These missions are presently under analysis and will be reported in journal articles within the next two years.
In general data quality for IFC-5 was very good. A full data quality report is given in the Known Problems with the Data Section.
Dr. Robert Louis Grossman
Aircraft Investigation of Boundary Layer Structure and Turbulence during FIFE.
Robert L. Grossman
University of Colorado
Mr. Vince Glover (FIFE-1987)
National Center for Atmospheric Research
Mr. Alan Schanot (FIFE-1989)
National Center for Atmospheric Research
The National Center for Atmospheric Research (NCAR) King Air participation in FIFE was endorsed by the Research Aviation Panel convened regularly by NCAR and through a special arrangement with the Atmospheric Sciences Division of the National Science Foundation (Dr. Jay Fein). NCAR King Air missions were under the scientific direction of Dr. Robert L. Grossman who was supported by NASA Grant NAG5-904. Pilots were Gil Summers - Jerry Tejcek (1987) and Jerry Tejcek - Henry Boynton (1989). NCAR Operations Managers were Vince Glover (1987) and Alan Schanot (1989).
The measuring devices on the NCAR King Air for FIFE are basically in situ devices. The aircraft is effectively an Eulerian measurement platform since each measurement along a level run and the level run itself take a short time compared to the interval over which substantial time variation in the atmosphere occurs. However, a complete mission, made up of several level legs, often covers a time period during which diurnal and mesoscale time variations can occur. Analysis of this data must take this into account. FIFE planning was successful in avoiding situations where deep convection could have caused mesoscale time and space variations. Grossman (1992b) concluded that the horizontal gradient estimates for runs less than 60 km have very low confidence; thus most of those data are suspect for theoretical reasons. Vertical flux sampling errors are discussed in Grossman 1992.
The theory of measurements for each of the nearly 100 instruments on the NCAR King Air is well beyond the scope of this presentation. For guidance contact Mr. Alan Schanot (see the Contact Information Section).
National Center for Atmospheric Research
Research Aviation Facility
Aircraft Research Instrumentation
King Air N312D - Project #7-217
P.I's: Hall (NASA) & Grossman (University of CO)
NOTE: Inter-comparison flights using CINDE King Air configuration did not have downward video or downward PRT-5 on board. In addition, radiation variables were not sampled and PMS probes were not turned on.
National Center for Atmospheric Research
Research Aviation Facility
Aircraft Research Instrumentation
King Air N312D - Project #8-220
FIFE - 1989, IFC-5
P.I.: R.L. Grossman, Univ. Colorado
User Supplied Equipment:
National Center for Atmospheric Research Beechcraft Super King Air B200T.
The NCAR King Air is maintained by the Research Aviation Facility (RAF) for airborne measurements in support of atmospheric research.
The variables measured are included in the equipment list in the Sensor/Instrument Description Section.
For guidance on particular instruments contact the Research Aviation Facility, National Center for Atmospheric Research, P.O. Box 3000, Boulder, CO 80307.
With one exception (described below), all instruments were calibrated according to NCAR RAF procedures. These usually involve calibration to tertiary NIST standards. For details on NCAR RAF calibration procedures contact either Vince Glover (IFC-1) or Alan Schanot (IFC-5) at NCAR Research Aviation Facility, P.O. Box 3000, Boulder, CO 80307; phone (303)497-1030.
The exception, noted above, is the calibration of the Lyman Alpha humidity device. The data herein used the Friehe-Grossman Method which is described in Friehe et al., 1986. Additional information is contained in Appendix C of Grossman et al., 1992. This method depends upon the accurate calibration and operation of the thermoelectric dewpoint instrument on the aircraft. The method requires that each level leg be independently calibrated. The calibration coefficients are checked for altitude (pressure and/or temperature) dependence. In the case of both IFC-1 and -5 the calibration coefficients were averaged for all legs in the well-mixed layer for a given mission since little altitude dependence was noted for the slope of the calibration curve (which is important to the estimation of the moisture flux). This introduced a 2 to 6% error in the moisture flux which should be added to the errors discussed in Grossman et al. 1992b.
Not available at the revision.
Not available at the revision.
NCAR RAF calibrates their instrumentation twice for a given project. Once before the aircraft leaves for the field experiment and when the aircraft returns. The Lyman-alpha calibration, as described above, was performed for each level leg in a given mission.
During IFC-1, one comparison mission was flown with the NAE (Canada) Twin Otter on 12 July 87. Several comparison missions were flown with the NAE Twin Otter during IFC-5. The results of these comparison missions showed that in general each aircraft was within a few percent of the other even though instrumentation and calibrations were different for the two. Details of the inter-comparison missions can be found in MacPherson et al., 1992.
Airborne in situ measurement of the primary variables which go into the computation of the 34 variables used in the estimation of mean values and higher moment statistics is complex. Each aviation facility (and experimenter, in some cases) has his/her own methodology. To check these methods and instruments an analysis of several wing-to-wing comparisons between the NCAR King Air and NAE Twin Otter made during FIFE appears in MacPherson et al., 1992.
The pattern of the aircraft flight track is an important consideration. These patterns are described in the Discussion Section. The first line of each data block has the start time/start point and end time/end point of the level leg to which the data refer; THE TIME SEQUENCE OF THESE LEVEL LEGS SHOULD BE REVIEWED BEFORE SERIOUS ANALYSIS OF THE DATA BEGIN.
Visual observations for each of the missions were recorded in two ways. First by notes taken by Dr. Grossman and secondly by videotapes recorded by two side-looking and one downward looking video cameras. A copy of the handwritten notes and videos can be obtained from the FIFE Information System. A flight-by-flight discussion of these observations is beyond the scope of the project and is actually part of the interpretation of the data by an individual investigator. Dr. Grossman, with a few days notice, would be able to discuss his observations with an interested investigator.
The FIFE study area with areal extent of 15 km by 15 km, is located south of the Tuttle Reservoir and Kansas River, and about 10 km from Manhattan, Kansas, USA. The northwest corner of the area has UTM coordinates of 4,334,000 Northing and 705,000 Easting in UTM zone 14.
The spatial resolution of the data is related to the sampling interval and the length of the individual level legs or pattern of level legs. The sampling interval determines the shortest length scale resolvable by the instruments and the length of the level leg determines the largest length scale resolvable. The data presented here only refers to the length of the level leg. For reference, the mean parameters presented (such as pressure, temperature, mixing ratio, etc.) were collected at one sample per-second (equivalent to about 80 meters horizontal distance through the atmosphere) and the turbulence parameters (such as vertical wind speed, Lyman alpha moisture, fluxes, etc.) were collected at 50 samples per second and block averaged to an effective sampling interval of 20 samples per second (equivalent to about 4 meters horizontal distance through the atmosphere). All data were digitally over sampled and high pass filtered to reduce aliasing and electrical interference from the many sources of EM radiation on the aircraft.
Most NCAR King Air Missions were over the FIFE study area, therefore refer to length scales of the order 15 by 15 kilometers.
The temporal resolution of the NCAR King Air aircraft data in FIFE was episodic with three to five hours of measurement per mission. There were never more than two missions in a day. Thus the aircraft data is not presented as a continuous data stream sampled at given intervals throughout the day. Flight operations were constrained by daylight hours.
FIFE-87 NCAR KING AIR FLIGHT SUMMARY 1987 Date,Run No. FIFE Flight Type Remarks ------------ ---------------- -------------------------------- 5/26 CMP-2 (F2) Flux profiles over north end of Konza site. Orientation. 5/30 CMP-2 (F1) Flux profiles over north end of Konza site. Good mission. 6/1,#1 CMP-1 (F1a) Flux profiles over north end of Konza site. Concentrate on lower subcloud layer. 6/1,#2 CMP-1 (F1a) Flux profiles over north end of Konza site. Concentrate on lower subcloud layer. 6/3 IMP-E Regional Survey to NE of Konza site. Two levels in subcloud layer. 6/4,#1 CMP-1 (F1a) Flux profiles over north end of Konza site. Concentrate on lower subcloud layer. 6/4,#2 CMP-1 (F1a) Flux profiles over north end of Konza site. Concentrate on lower subcloud layer. Further work on flux statistics with 6 legs each at lowest and highest levels. 6/6,#1 CMP-1 (F1a) Time series of fluxes at two levels: near surface and top of mixed layer. Possible entrainment statistics. 6/6,#2 CMP-1 (F1a) Time series of fluxes at two levels: near surface and top of mixed layer. Possible entrainment statistics. FIFE MISSION SUMMARY FOR NCAR KING AIR 1989 (IFC-5) Date/Time Flight Plan Weather Remarks (Flight No.)* --------- ------------ ------------------ ------------------ 26 JULY PLUS Pattern: Began with sctd Ci Regional run. Gust 1007:23 to 4 levels then brkn Scu and probe calibration 1235:42 CDT (RF01) sctd CuCg. Hazy maneuvers. 27 JULY T Pattern: Sctd variable brkn Regional run. Gust 1235:15 to 4 levels Cu; variable cloud probe calibration 1618:37 CDT base. maneuvers. Lidar (RF02) run. Twin Otter mission in morning. 28 JULY Stack: 3 Sctd Cu. Regional run. 1026:32 to levels plus 1235:42 CDT Grid using Twin Otter (RF03) 02 AUGUST L Pattern: 2 Brkn Cu, sctd CuCg Regional run. 1210:54 to levels. sctd As and Ci. Lidar run. Twin 1513:37 CDT Cloud cover dimin- Otter mission in (RF04) ished with time. morning. 04 AUGUST Stack plus Clear, hazy, no FIFE Golden Day. 1149:13 to L pattern: change with time! Regional Run. Gust 1647:56 CDT 4 levels probe calibration maneuvers. Twin (RF05) Otter grid pattern in morning and late afternoon. 06 AUGUST Stack plus Clear becoming Intercompare with 1247:13 to L pattern: sctd Cu. Winds Twin Otter. Lots 1649:32 CDT 4 levels from NNE-NE. of bugs on Very hazy. windshield. Gust (RF06) probe calibration maneuvers. Twin Otter L pattern in morning and late afternoon. 07 AUGUST T pattern: Sctd Cu, sctd Regional run. Much 1254:20 to 4 levels Ci. Very clear fewer bugs this 1254:20 to 4 levels Ci. Very clear day. Twin Otter 1543:19 CDT visibility. mission in morning (RF07) Winds from N. and late Cold front afternoon. passage. 08 AUGUST L pattern: Clear becoming Regional run. 0921:17 to 2 levels brkn Cu. Light Lidar run. Time 1334:44 CDT winds. variation (RF08) objective. 11 AUGUST Telescoping, Brkn Cu, very Regional run 1124:54 to 3-level stacks hazy. Later sctd intercompare with 1705:21 CDT from Konza to Cu, brkn Ac, sctd Twin Otter nr. Emporia, Ci. outbound from Ks. Salina. Scale dependence (RF09) objective. 12 AUGUST Regional scale Sctd Cu, brkn Ac, Regional run 1051:11 to T pattern plus sctd Ci. Cu became intercompare with 1457:18 CDT Grid (Twin brkn with time Twin Otter. Scale Otter) dependence objective. Lake (RF10) calibration of infrared surface temperature.
* These flight numbers have been deduced by the information system staff using the information provided by A. Schanot that appears in the Known Problems with the Data Section of this document. These flight numbers provide the link between the information given here and the information given for IFC-5 in the Known Problems with the Data Section.
On those missions devoted to time variation, intervals ranged between hours and ten's of minutes, depending upon the flight pattern flown.
The SQL definition for this tables is found in the AF_RAW.TDF file located on FIFE CD-ROM Volume 1.
Parameter/Variable Description Range Units Source
OBS_DATE The date the observation was made on, in the format (DD-MMM-YY).
START_TIME The starting time for the [GMT] observation run in GMT, in the format (HHMM). The seconds for this time is stored in START_SECONDS.
START_SECONDS The seconds component of the [GMT] START_TIME (format SS).
DURATION The duration of the flight in the format (MMSS).
AIRCRAFT_ID The ID name for the aircraft which made the observation run.
START_LAT The starting latitude for the observation run.
START_LON The starting longitude for the observation run.
START_NORTHING The starting northing position of [meters] the aircraft in UTM coordinates.
START_EASTING The starting easting position of [meters] the aircraft in UTM coordinates.
END_LAT The ending latitude for the observation run.
END_LON The ending longitude for the observation run.
END_NORTHING The ending northing position of [meters] the aircraft in UTM coordinates.
END_EASTING The ending easting position of [meters] the aircraft in UTM coordinates.
HEADING The heading of the aircraft. [degrees from North]
HEIGHT_ABOVE_MEAN_SEA_LVL The altitude of the aircraft [meters] above mean sea level, as determined by air pressure.
HEIGHT_ABOVE_GRND_LVL The altitude of the aircraft [meters] above the ground, as determined by radar.
AIR_TEMP_MEAN The mean air temperature. [degrees Celsius]
POTNTL_TEMP_MEAN The potential mean air temperature. [degrees Kelvin]
MIX_RATIO_MEAN The mixing ratio taken from a [grams] dew-point hygrometer. [kg^-1]
NS_WIND_VELOC_MEAN The mean north/south wind [meters] component (V), with north being [sec^-1] positive.
EW_WIND_VELOC_MEAN The mean east/west wind component [meters] (U), with east being positive. [sec^-1]
PRESS_MEAN The mean air pressure. [millibars]
SURF_TEMP_MEAN The mean surface temperature. [degrees Celsius]
DOWNWELL_RADTN_MEAN The mean downwelling radiation [Watts] count. [meter^-2]
UPWELL_RADTN_MEAN The mean upwelling radiation count. [Watts] [meter^-2]
VEG_INDEX_MEAN The mean vegetation (greenness) index.
AIR_TEMP_RMS The root mean square of the [degrees temperature recorded in column Celsius] AIR_TEMP_MEAN.
POTNTL_TEMP_RMS The root mean square of the [degrees potential temperature recorded in Kelvin] the column POTNTL_TEMP_MEAN.
MIX_RATIO_RMS The root mean square of the [grams] mixing ratio recorded in the [kg^-1] column MIX_RATIO_MEAN, taken from a dew-point hygrometer.
NS_WIND_VELOC_RMS The root mean square of the [meters] north/south wind component [sec^-1] recorded in column NS_WIND_VELOC_MEAN.
EW_WIND_VELOC_RMS The root mean square of the [meters] east/west wind component recorded [sec^-1] in column EW_WIND_VELOC_MEAN.
PRESS_RMS The root mean square of the [millibars] pressure recorded in column PRESS_MEAN.
SURF_TEMP_RMS The root mean square of the [degrees surface temperature recorded in Celsius] column SURF_TEMP_MEAN.
DOWNWELL_RADTN_RMS The root mean square of the [Watts] downwelling radiation count [meter^-2] recorded in column DOWNWELL_RADTN_MEAN.
UPWELL_RADTN_RMS The root mean square of the [Watts] upwelling radiation recorded in [meter^-2] column UPWELL_RADTN_MEAN.
VEG_INDEX_RMS The root mean square of the vegetation (greenness) index recorded in column VEG_INDEX_MEAN.
AIR_TEMP_LINEAR The linear trend of the [degrees temperature recorded in the column Celsius] AIR_TEMP_MEAN. [meter^-1]
POTNTL_TEMP_LINEAR The linear trend of the potential [degrees temperature recorded in column Kelvin] POTNTL_TEMP_MEAN. [meter^-1]
MIX_RATIO_LINEAR The linear trend of the mixing [grams] ratio recorded in column [kg^-1] MIX_RATIO_MEAN (derived from dew [meter^-1] point).
NS_WIND_VELOC_LINEAR The linear trend of the [meters] north/south wind component [sec^-1] recorded in column [meter^-1] NS_WIND_VELOC_MEAN.
EW_WIND_VELOC_LINEAR The linear trend of the east/west [meters] wind component recorded in column [sec^-1] EW_WIND_VELOC_MEAN. [meter^-1]
PRESS_LINEAR The linear trend of the pressure [millibars] recorded in column PRESS_MEAN. [meter^-1]
SURF_TEMP_LINEAR The linear trend of the surface [degrees temperature recorded in column Celsius] SURF_TEMP_MEAN. [meter^-1]
DOWNWELL_RADTN_LINEAR The linear trend of the [Watts] downwelling radiation count [meter^-2] recorded in DOWNWELL_RADTN_MEAN. [meter^-1]
UPWELL_RADTN_LINEAR The linear trend of the upwelling [Watts] radiation count recorded in column [meter^-2] UPWELL_RADTN_MEAN. [meter^-1]
VEG_INDEX_LINEAR The linear trend of the vegetation (greenness) index recorded in column VEG_INDEX_MEAN.
MOIST_AIR_DENSITY_X_CP The moist air density times [Watts][sec] specific heat capacity (CP). [degrees Kelvin^-1]
LATENT_HEAT_OF_VAPOR The latent heat of vaporization [Watts] at 20 degrees Celsius. [sec] [gram^-1]
MOIST_AIR_DENSITY The moist air density. [kg] [meter^-3]
VERT_GUST_VELOC_RMS_RAW The root mean square of the [meters] vertical wind gust velocity. [sec^-1]
NS_GUST_VELOC_RMS_RAW The root mean square of the [meters] north/south wind (U) gust velocity. [sec^-1]
EW_GUST_VELOC_RMS_RAW The root mean square of the [meters] east/west wind (V) gust velocity. [sec^-1]
ALONG_WIND_VELOC_RMS_RAW The root mean square of the [meters] along-wind component of the wind [sec^-1] gust velocity.
ACROSS_WIND_VELOC_RMS_RAW The root mean square of the [meters] across-wind component of the wind [sec^-1] gust velocity.
POTNTL_TEMP_RMS_RAW The root mean square of the [degrees potential temperature. Kelvin]
WATER_MIX_RATIO_RMS_RAW The root mean square of the water [grams] mixing ratio (lyman alpha). [kg ^-1]
CO2_MIX_RATIO_RMS_RAW The root mean square of the [milligrams] carbon dioxide content. [kg^-1]
VERT_GUST_VELOC_SKEW_RAW The skewness of the vertical gust wind velocity.
NS_GUST_VELOC_SKEW_RAW The skewness of the north/south wind gust velocity.
EW_GUST_VELOC_SKEW_RAW The skewness of the east/west wind gust velocity.
ALONG_WIND_VELOC_SKEW_RAW The skewness of the along-wind component of the wind gust velocity.
ACROSS_WIND_VELOC_SKEW_RAW The skewness of the across-wind component of the wind gust velocity.
POTNTL_TEMP_SKEW_RAW The skewness of the potential temperature.
WATER_MIX_RATIO_SKEW_RAW The skewness of the water mixing ratio.
CO2_MIX_RATIO_SKEW_RAW The skewness of the carbon dioxide content.
NS_MOMNTM_FLUX_RAW The north/south momentum flux, [Newtons] calculated from W*V (wind [meter^-2] components).
EW_MOMNTM_FLUX_RAW The east/west momentum flux, [Newtons] calculated from W*U (wind [meter^-2] components).
ALONG_MOMNTM_FLUX_RAW The along-wind momentum flux, [Newtons] calculated from W*along-wind gust [meter^-2] (wind components).
ACROSS_MOMNTM_FLUX_RAW The across-wind momentum flux, [Newtons] calculated from W*across-wind gust [meter^-2] (wind components).
SENSIBLE_HEAT_FLUX_RAW The sensible heat flux. [Watts] [meter^-2]
LATENT_HEAT_FLUX_RAW The latent heat flux. [Watts] [meter^-2]
CO2_FLUX_RAW The carbon dioxide flux. [kg] [hectare^-1] [hour^-1]
NS_MOMNTM_CC_RAW The correlation coefficient for vertical wind velocity and north/south wind gusts.
EW_MOMNTM_CC_RAW The correlation coefficient for vertical wind velocity and east/west wind gusts.
ALONG_MOMNTM_CC_RAW The correlation coefficient for vertical wind velocity and along-wind component of the wind gust velocity.
ACROSS_MOMNTM_CC_RAW The correlation coefficient for vertical wind velocity and across-wind component of the wind gust velocity.
SENSIBLE_HEAT_CC_RAW The correlation coefficient for the sensible heat flux.
LATENT_HEAT_CC_RAW The correlation coefficient for the latent heat flux.
CO2_FLUX_CC_RAW The correlation coefficient for the CO2 flux.
MIX_RATIO_CC_RAW The correlation coefficient for the mixing ratio * potential temperature.
COMMENTS Any comments pertaining to this record.
FIFE_DATA_CRTFCN_CODE The FIFE Certification Code for * the data, in the following format: CPI (Certified by PI), CPI-??? (CPI - questionable data).
LAST_REVISION_DATE data, in the format (DD-mmm-YY).
* Valid levels
The primary certification codes are: EXM Example or Test data (not for release) PRE Preliminary (unchecked, use at your own risk) CPI Checked by Principal Investigator (reviewed for quality) CGR Checked by a group and reconciled (data comparisons and cross checks)
The certification code modifiers are: PRE-NFP Preliminary - Not for publication, at the request of investigator. CPI-MRG PAMS data that is "merged" from two separate receiving stations to eliminate transmission errors. CPI-??? Investigator thinks data item may be questionable.
OBS_DATE START_TIME START_SECONDS DURATION AIRCRAFT_ID START_LAT --------- ---------- ------------- ---------- ----------- ---------- 12-AUG-89 1642 12 526 NCAR 3904.9 12-AUG-89 1650 37 654 NCAR 3904.9 12-AUG-89 1659 44 645 NCAR 3904.9 12-AUG-89 1710 3 614 NCAR 3904.9 START_LON START_NORTHING START_EASTING END_LAT END_LON END_NORTHING ---------- -------------- ------------- ---------- ---------- ------------ -9633.7 3905.3 -9615.3 -9614 3904.9 -9637.1 -9638.3 3905.1 -9615.5 -9616.1 3904.9 -9636.9 END_EASTING HEADING HEIGHT_ABOVE_MEAN_SEA_LVL HEIGHT_ABOVE_GRND_LVL ----------- ---------- ------------------------- --------------------- 91 1158 100 266 863 560 92 520 192 265 420 89 AIR_TEMP_MEAN POTNTL_TEMP_MEAN MIX_RATIO_MEAN NS_WIND_VELOC_MEAN ------------- ---------------- -------------- ------------------ 16.13 299.9 8.76 5.25 19.22 300.02 8.77 5.82 22.82 300.15 8.9 4.83 24.07 300.38 8.88 5.73 EW_WIND_VELOC_MEAN PRESS_MEAN SURF_TEMP_MEAN DOWNWELL_RADTN_MEAN ------------------ ---------- -------------- ------------------ -.38 881.5 33 800 -.17 913.7 34 769 -.32 952.3 35.1 735 -.15 963.8 36 886 UPWELL_RADTN_MEAN VEG_INDEX_MEAN AIR_TEMP_RMS POTNTL_TEMP_RMS ----------------- -------------- ------------ --------------- 146 99.999 .11 .1 99.999 .15 .15 .27 99.999 .18 .18 .18 99.999 .29 .29 .24 MIX_RATIO_RMS NS_WIND_VELOC_RMS EW_WIND_VELOC_RMS PRESS_RMS ------------- ----------------- ----------------- ---------- .37 .91 .91 .4 .85 .92 .4 2.7 1.07 1.19 .3 3.8 1.12 1.39 .2 3.9 SURF_TEMP_RMS DOWNWELL_RADTN_RMS UPWELL_RADTN_RMS VEG_INDEX_RMS ------------- ------------------ ---------------- ------------- 2.8 121 14 99.999 111 15 99.999 0 136 24 99.999 0 93 16 99.999 0 AIR_TEMP_LINEAR POTNTL_TEMP_LINEAR MIX_RATIO_LINEAR --------------- ------------------ ---------------- -1.680E-07 -.00000011 -.00000894 .000000445 -.00000362 .00000153 -4.410E-07 .00000416 .000000446 .000000913 -.0000067 -.00000148 NS_WIND_VELOC_LINEAR EW_WIND_VELOC_LINEAR PRESS_LINEAR -------------------- -------------------- ------------ -.00000191 -1.570E-07 .00000284 .000000694 .00000105 .0000868 .00000129 -.00000386 -.0000801 -.00000135 -.00000404 .0000717 SURF_TEMP_LINEAR DOWNWELL_RADTN_LINEAR UPWELL_RADTN_LINEAR ---------------- --------------------- ------------------- .000051 .00203 .000575 .00312 .0003 99.999 -.0000986 .000499 99.999 .00501 .000245 99.999 VEG_INDEX_LINEAR MOIST_AIR_DENSITY_X_CP LATENT_HEAT_OF_VAPOR ---------------- ---------------------- -------------------- 99.999 1061.2 2575.3 1.23 2633.2 1.083 1.08 2701 1.115 .99 2719 1.124 MOIST_AIR_DENSITY VERT_GUST_VELOC_RMS_RAW NS_GUST_VELOC_RMS_RAW ----------------- ----------------------- --------------------- 1.056 1.1 .91 -.11 .85 .92 -.26 1.07 1.19 -.33 1.12 1.39 EW_GUST_VELOC_RMS_RAW ALONG_WIND_VELOC_RMS_RAW ACROSS_WIND_VELOC_RMS_RAW --------------------- ------------------------ ------------------------- .91 .91 .91 .85 .92 .15 1.07 1.19 .17 1.12 1.39 .29 POTNTL_TEMP_RMS_RAW WATER_MIX_RATIO_RMS_RAW CO2_MIX_RATIO_RMS_RAW ------------------- ----------------------- --------------------- .12 .39 99.999 .29 99.999 1.23 .19 99.999 1.07 .26 99.999 .99 VERT_GUST_VELOC_SKEW_RAW NS_GUST_VELOC_SKEW_RAW EW_GUST_VELOC_SKEW_RAW ------------------------ ---------------------- ---------------------- 1.177 -.027 .368 -.279 .392 -.274 -.265 .007 -.298 -.404 .026 -.418 ALONG_WIND_VELOC_SKEW_RAW ACROSS_WIND_VELOC_SKEW_RAW ------------------------- -------------------------- -.084 -.372 -.397 .674 -.01 1.146 -.033 1.264 POTNTL_TEMP_SKEW_RAW WATER_MIX_RATIO_SKEW_RAW CO2_MIX_RATIO_SKEW_RAW -------------------- ------------------------ ---------------------- .32 -.903 99.999 -1.459 99.999 .625 -.887 99.999 .398 -.197 99.999 .292 NS_MOMNTM_FLUX_RAW EW_MOMNTM_FLUX_RAW ALONG_MOMNTM_FLUX_RAW ------------------ ------------------ --------------------- -.13 .21 -.14 -.03 -.11 .03 .15 -.27 -.13 -.1 -.33 .1 ACROSS_MOMNTM_FLUX_RAW SENSIBLE_HEAT_FLUX_RAW LATENT_HEAT_FLUX_RAW ---------------------- ---------------------- -------------------- -.2 7 444 17 431 99.999 95 250 99.999 146 294 99.999 CO2_FLUX_RAW NS_MOMNTM_CC_RAW EW_MOMNTM_CC_RAW ALONG_MOMNTM_CC_RAW ------------ ---------------- ---------------- ------------------- 99.999 -.12 .2 -.14 -.09 -.02 -.09 .02 -.21 .11 -.21 -.09 -.27 -.06 -.26 .07 ACROSS_MOMNTM_CC_RAW SENSIBLE_HEAT_CC_RAW LATENT_HEAT_CC_RAW -------------------- -------------------- ------------------ -.19 .05 .4 .08 .45 99.999 .46 .45 99.999 .45 .41 99.999 CO2_FLUX_CC_RAW MIX_RATIO_CC_RAW COMMENTS --------------- ---------------- -------------------- 99.999 -.46 -.35 -.1 .29 -.27 .19 -.35 FIFE_DATA_CRTFCN_CODE LAST_REVISION_DATE --------------------- ------------------ CPI 03-SEP-92 CPI 03-SEP-92 CPI 03-SEP-92 CPI 03-SEP-92
The NCAR King Air aircraft data in FIFE was collected via three to five hours of measurement per mission, with a maximum of two missions in a day. The aircraft data is not presented as a continuous data stream sampled at given intervals throughout the day. The sampling interval for data collection determines the shortest length scale resolvable by the instruments and the length of the level leg determines the largest length scale resolvable. For reference, the mean parameters presented (e.g., pressure, temperature were collected at one sample per-second (i.e., approximately 80 meters horizontal distance) and the turbulence parameters (e.g., vertical wind speed) were collected at 50 samples per second and block averaged to an effective sampling interval of 20 samples per second (equivalent to about 4 meters horizontal distance).
A general description of data granularity as it applies to the IMS appears in the EOSDIS Glossary.
The CD-ROM file format consists of numerical and character fields of varying length separated by commas. The character fields are enclosed with a single apostrophe. There are no spaces between the fields. Each file begins with five header records. Header records contain the following information: Record 1 Name of this file, its table name, number of records in this file, path and name of the document that describes the data in this file, and name of principal investigator for these data. Record 2 Path and filename of the previous data set, and path and filename of the next data set. (Path and filenames for files that contain another set of data taken at the same site on the same day.) Record 3 Path and filename of the previous site, and path and filename of the next site. (Path and filenames for files of the same data set taken on the same day for the previous and next sites (sequentially numbered by SITEGRID_ID)). Record 4 Path and filename of the previous date, and path and filename of the next date. (Path and filenames for files of the same data set taken at the same site for the previous and next date.) Record 5 Column names for the data within the file, delimited by commas. Record 6 Data records begin.
Each field represents one of the attributes listed in the chart in the Data Characteristics Section and described in detail in the TDF file. These fields are in the same order as in the chart.
See NCAR/RAF Bulletin No. 9 (by Miller and Friesen) for details of the formulas used to obtain the derived data from the aircraft measurements; this reference is available from the Research Aviation Facility, NCAR, P.O. Box 3000, Boulder, CO 80307. Grossman 1992 discusses the eddy correlation flux calculation method. Mean, standard deviation, skewness estimates were calculated from standard statistical formulae.
The derivation techniques and algorithms were discussed previously. The main ones were the Lyman-alpha calibration technique and eddy correlation flux technique.
Data Processing by NCAR/RAF: The aircraft data analog signals were initially low pass filtered with a cutoff frequency of 20 Hz, the data were then digitally sampled at 50 samples per second, digital filters were used to low pass again at 20 Hz, The data then were block averaged to a 10 sample per second sampling rate and 1 sample per second sampling rate. Some slow response data obtained at 1 sample per second were interpolated to 20 samples per second: pressure was the main parameter for this project.
Data Processing by R.L. Grossman: Data were despiked by removing all data which were 5 standard deviations from the mean. This represented less than 1% of the data. Moisture mixing ratio was used to avoid corrections due to the dependence of density on temperature. For the filtered data a high-pass recursive filter was used. The filter used here is a third-order high-pass digital filter, derived from the maximally-flat approximation (Budak 1974) and converted to time domain using the pole-zero technique of Jacquot 1981. The cutoff frequency of the filter is fixed at .017 Hz (85 m/s average airspeed divided by a wavelength of 5000 m). Fluxes were computed using standard eddy correlation technique based upon Reynolds Averaging Rules.
Discussed in previous sections.
Only the highlights are given here since it is beyond the scope of the project to discuss potential errors for all of the measurements on the aircraft.
Errors are discussed previously.
This is discussed in the Notes Section.
NCAR/RAF experts carefully went over the data before it was released to the Principal Investigator. Their reports are given in the Known Problems with the Data Section. The Principal Investigator also looked very carefully at the data for the missions flown on 1 June, 4 June, and 6 June 1987 before publishing results. Level legs for all missions were subjected to criteria based on aircraft altitude changes, position over the FIFE study area, and roll altitude of the aircraft. However, missions other than 1, 4, and 6 June 1987 may contain subtle errors because the principal investigator did not subject these data to the same scrutiny as those used in published results.
Based upon four peer reviewed articles based upon the 1987 data only, the principal investigator feels that the data are of high quality. Limitations have been discussed in the publications as well as in this documentation. The judgment is based also on the analysis of wing-to-wing inter-comparison of measurements as well as computational techniques reported in MacPherson 1992.
A complete list can be found in NCAR/RAF Bulletin No.14, a selection from that list is presented below:
Parameter/Variable Accuracy Resolution ------------------ -------- ----------- Mag. heading 0.05 deg .00275 deg Static press. 1 kPa .06 kPa Geom. Alt. 1.5m, 0-152m 7% , 152-930m 0.1 m Lat/lon < 1 nm per hr .0014 deg Ground veloc. < 1 knot/hr drift .04 m/s Vert. veloc. 0.1 m/s .012 m/s Pitch/roll .05 deg .00275 deg Platform hdg. .05 deg .00275 deg Airspeed .07 kPa .006 kPa Total press. 1.0 kPa .034 kPa Air temp. 0.5 C .006 C Dewpoint temp. 0.5 C, > 0 C .006 C, 1.0 C, < 0 C Note: these have to be converted to mixing ratio using temperature and pressure errors. Vapor density n/a .0006 g/m**3 wind components 1.0 m/s .012 m/s Global Infra-red Radiation not given .40 W/m^2 Global Solar Radiation not given .12 W/m^2
FIS staff applied a general Quality Assessment (QA) procedure to the data to identify inconsistencies and problems for potential users. As a general procedure, the FIS QA consisted of examining the maximum, minimum, average, and standard deviation for each numerical field in the data table. An attempt was made to find an explanation for unexpected high or low values, values outside of the normal physical range for a variable, or standard deviations that appeared inconsistent with the mean. In some cases, histograms were examined to determine whether outliers were consistent with the shape of the data distribution.
The discrepancies, which were identified, are reported as problems in the Known Problems with the Data Section.
The data verification performed by the ORNL DAAC deals with the quality of the data format, media, and readability. The ORNL DAAC does not make an assessment of the quality of the data itself except during the course of performing other QA procedures as described below.
The FIFE data were transferred to the ORNL DAAC via CD-ROM. These CD-ROMs are distributed by the ORNL DAAC unmodified as a set or in individual volumes, as requested. In addition, the DAAC has incorporated each of the 98 FIFE tabular datasets from the CD-ROMs into its online data holdings. Incorporation of these data involved the following steps:
Each distinct type of data (i.e. "data set" on the CD-ROM), is accompanied by a documentation file (i.e., .doc file) and a data format/structure definition file (i.e., .tdf file). The data format files on the CD-ROM are Oracle SQL commands (e.g., "create table") that can be used to set up a relational database table structure. This file provides column/variable names, character/numeric type, length, and format, and labels/comments. These SQL commands were converted to SAS code and were used to create SAS data sets and subsequently to input data files directly from the CD-ROM into a SAS dataset. During this process, file names and directory paths were captured and metadata was extracted to the extent possible electronically. No files were found to be corrupted or unreadable during the conversion process.
Additional Quality Assurance procedures were performed as follows:
As errors are discovered in the online tabular data by investigators, users, or DAAC staff, corrections are made in cooperation with the principal investigators. These corrections are then distributed to users. CD-ROM data are corrected when re-mastering occurs for replenishment of CD-ROM stock.
IFC-1 Data Quality Report from V. Glover
The National Center for Atmospheric Research Aviation Facility has given permission to copy their data quality report for the NCAR King Air participation in FIFE IFC-1. This report was authored by Mr. Vince Glover of NCAR and appears in its entirety. Additional comments by the principal investigators (Grossman, Mahrt, and Hall) are enclosed by parentheses within the text.
"This summary has been written to outline areas of concern in the data set and is not intended to point out every bit of questionable data. It is hoped that this information will facilitate the use of the data as the research concentrates on specific times and flights. In general, the data set is of excellent overall quality with very little loss of data."
"The following report is organized into two sections. The first lists general limitations and systematic biases in the RAF measurements. The second section lists isolated problems on a flight-by-flight basis."
Data Quality Report
King Air N312D-Project # 0-220
This summary has been written to outline basic instrumentation problems affecting the data set and is not intended to point out every bit of questionable data. It is hoped that this information will facilitate use of these data as the research concentrates on specific flights and times.
The following report is organized into two sections. The first section lists reoccurring problems, general limitations, and systematic biases in the RAF measurements. The second section lists isolated problems occurring on a flight-by-flight basis. Some User supplied equipment was included in the instrument package. No attempt has been made to evaluate the performance of any of that equipment.
Special sets of in-flight calibration maneuvers were conducted on flights TF01, RF02 and RF06 to aid in the performance analysis of the wind gust measurements. All of the information, including the summary of INS performance, indicated that the wind measurement system was performing within standard RAF specifications. The time intervals for each set of maneuvers have been documented in both the flight-by-flight data quality review and on the individual Research Flight Forms prepared for each flight.
Lyman-alpha hygrometers are susceptible to in-flight drift in the instrument's bias voltage. Due to this problem, RAF uses a special data processing technique to remove the bias drift by referencing the long term humidity values to one of the more stable thermoelectric dew point sensors. This technique can result in occasional large spikes in the derived Lyman-alpha data (RHOLA, RHOLA1) which often effect the auto-scaling features in the microfilm plotting routines and wash out the plots. Short (2--3 sec) intervals around these spikes should be considered as bad data, but the remaining data points, as recorded on magnetic tape, will be valid. The performance of the data processing technique can be monitored through an examination of the difference plots (DRFHBL, DFRHB1) included in the GENPRO data set. Information on this technique, and literature references on high rate humidity measurements are available in RAF Bulletin # 22. Peak to peak response characteristics for each Lyman-alpha system were determined using the NCAR gas calibration device which is patterned after the "Stull" Lyman-alpha calibration system discussed in the literature. Although both systems generally performed well, sensor SN-1 (VLA, RHOLA) exhibited less drift and should be used as the primary high rate data source.
The microwave refractometer is a high rate humidity sensor currently under development at RAF and was included in this program on an experimental basis. System response is stable with pre and post project calibrations being conducted in the RAF calibration lab. In its current state of development, however, certain flight specific adjustments are necessary to convert the direct measurement of refractivity to an absolute humidity. These adjustments are applied systematically and resulted in only minimal impact on the humidity measurements. The instrument performed well throughout the experiment so the data have been included in the GENPRO data output. Performance during specific intervals can be monitored through an examination of the difference plot (DFRHBR) included in the data set.
The dual wavelength vegetation sensor is a new device and its performance characteristics are not well known. It appeared to perform well with signal fluctuations (VM660, VM730) mirroring some of the other radiometric measurements.
As with all radiometric sensors, these units are hard mounted and none of the data have been corrected for changes in the aircraft's flight attitude.
FIS staff general QA found the following anomalies in Dr. Grossman's aircraft flux data:
The main problems were with the Lyman-alpha Hygrometer Calibration, choosing the level leg timings for fluxes, method of flux calculation, and surface temperature estimation. All of these have been discussed or referenced in the sections above. Here is a capsule discussion.
Not available at this revision.
The Raw Atmospheric Turbulence Data from the NCAR King Air Data Set can be used to help describe the structure of the atmospheric boundary layer over the FIFE study area, increase knowledge of the physical processes active in the daytime boundary layer, and explore the relationship of surface properties to the time and spatial variation in the structure of the boundary layer.
The FIFE field campaigns were held in 1987 and 1989 and there are no plans for new data collection. Field work continues near the FIFE site at the Long-Term Ecological Research (LTER) Network Konza research site (i.e., LTER continues to monitor the site). The FIFE investigators are continuing to analyze and model the data from the field campaigns to produce new data products.
Software to access the data set is available on the all volumes of the FIFE CD-ROM set. For a detailed description of the available software see the Software Description Document.
ORNL DAAC User Services
Oak Ridge National Laboratory
Telephone: (865) 241-3952
FAX: (865) 574-4665 Email: email@example.com
ORNL Distributed Active Archive Center
Oak Ridge National Laboratory
Telephone: (865) 241-3952
FAX: (865) 574-4665 Email: firstname.lastname@example.org
Users may place requests by telephone, electronic mail, or FAX. Data is also available via the World Wide Web at http://daac.ornl.gov.
FIFE data are available from the ORNL DAAC. Please contact the ORNL DAAC User Services Office for the most current information about these data.
NCAR/RAF processed tapes containing the original data from which the derived data (statistics, fluxes, etc.) were estimated can be obtained from the FIS or from NCAR/RAF (cost reimbursable). These data are in the public domain. NCAR may also be able to provide these data in digital file format.
Microfilms of the output from the original data tapes discussed in the Tape Products Section are available from the ORNL DAAC.
Video camera (side-looking, downward looking) tapes from the aircraft are available from the ORNL DAAC.
Raw Atmospheric Turbulence Data from the NCAR King Air are available on FIFE CD-ROM Volume 1. The CD-ROM filename is as follows:
Where yyyy are the four digits of the century and year (e.g., Y1987). Note: capital letters indicate fixed values that appear on the CD-ROM exactly as shown here, lower case indicates characters (values) that change for each path and file.
The format used for the filenames is: ydddMULT.sfx, where y is the last digit of the year (e.g., 7 = 1987, and 9 = 1989), ddd is the day of the year (e.g., 061 = sixty-first day in the year). The filename extension (.sfx), identifies the data set content for the file (see the Data Characteristics Section) and is equal to .WYR for the raw data.
Miller and Friesen NCAR/RAF Bulletin No. 9.
Anonymous NCAR/RAF Bulletin No. 14.
Betts, A.K., R.L. Desjardins, J.I. MacPherson, and R.D. Kelly. 1990. Boundary layer heat and moisture budgets from FIFE. Boundary Layer Meteorology. 50:109-137.
Betts, A.K., R.L. Desjardins, J.I. MacPherson. 1992. Budget analysis of the boundary layer grid flights during FIFE 1987. J. Geophys. Research. 97(D17):18,523-18.531.
Grossman, Robert L. 1992a. Sampling errors in the vertical fluxes of potential temperature and moisture measured by aircraft during FIFE. J. Geophys. Res. 97(D17):18,439-18,443.
Grossman, Robert L. 1991. Temporal variation of heat and moisture flux within the atmospheric boundary layer over a grassland. Ch. 16 in Land Surface Evaporation Fluxes: Their measurement and parameterization. (Schmugge and Andre, eds.). 755pp. Springer-Verlag, New York.
Grossman, Robert L. 1992b. Convective Boundary Layer Budgets of Moisture and Sensible Heat Over an unstressed prairie. J. Geophys. Res. 97(D17):18,425-18,438.
Kelly, R. 1992. Atmospheric boundary layer studies in FIFE: Challenges and advances. J. Geophys. Res. 97(D17):18,373-18,376.
Kelly, R.D. E.A. Smith, and J.I. MacPherson. 1987. A comparison of surface sensible and latent heat fluxes from aircraft and surface measurements in FIFE 1987. J. Geophys. Res. 97(D17):18,445-18,453.
MacPherson, J.I., R.L. Grossman, and R.D. Kelly. 1992. Inter-comparison results for FIFE flux aircraft. J. Geophys. Res. 97(D17):18,499-18,514.
Sellers, P.J., F.G. Hall, G.Asrar, D.E. Strebel, and R.E. Murphy. An overview of the First International Satellite Land Surface Climatology Project (ISLSCP) Field Experiment (FIFE). J. Geophys. Res. 97(D17):18,345-18,371.
Contact the EOS Distributed Active Archive Center (DAAC) at Oak Ridge National Laboratory (ORNL), Oak Ridge, Tennessee (see the Data Center Identification Section). Documentation about using the archive and/or online access to the data at the ORNL DAAC is not available at this revision.
A general glossary for the DAAC is located at Glossary.
A general list of acronyms for the DAAC is available at Acronyms.
April 29, 1994 (citation revised on October 14, 2002).
This document has been reviewed by the FIFE Information Scientist to eliminate technical and editorial inaccuracies. Previous versions of this document have been reviewed by the Principal Investigator, the person who transmitted the data to FIS, a FIS staff member, or a FIFE scientist generally familiar with the data. It is believed that the document accurately describes the data as collected and as archived on the FIFE CD-ROM series.
March 6, 1996.
Grossman, R. L. 1994. Aircraft Flux - Raw: Univ. Col. (FIFE). Data set. Available on-line [http://www.daac.ornl.gov] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A. doi:10.3334/ORNLDAAC/11. Also published in D. E. Strebel, D. R. Landis, K. F. Huemmrich, and B. W. Meeson (eds.), Collected Data of the First ISLSCP Field Experiment, Vol. 1: Surface Observations and Non-Image Data Sets. CD-ROM. National Aeronautics and Space Administration, Goddard Space Flight Center, Greenbelt, Maryland, U.S.A. (available from http://www.daac.ornl.gov).