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BOWEN RATIO SURFACE FLUX: KSU (FIFE)
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Bowen Ratio Surface Flux: KSU (FIFE)

Summary:

The Bowen Ratio Surface Flux Observations (KSU) Data Set contains surface flux measurements made at selected sites within the FIFE area. The sites were equipped with Bowen ratio equipment that was operated by several different groups. Each surface flux station was capable of measuring the fluxes of net radiation, latent heat and sensible heat. The Bowen ratio stations measured the soil heat flux as well. The components of the energy balance were determined with the Bowen Ratio Energy Balance (BREB) method. The BREB is a combination of the transport and the energy balance equations.

The surface flux and micrometeorological measurements available in this data set were collected from 23 locations with 27 site identifiers from 1987 through 1989. Thirteen of these locations were instrumented with stationary bowen ratio systems which collected daily measurements for months. These systems were all located in the northwest quadrant of the FIFE study area within the Konza Prairie Natural Research Area. Ten locations were instrumented in 1987 for a few days at a time with a portable Bowen ratio system. This roving system visited all but the southeast quadrant of the FIFE study area.

Table of Contents:

  1. Data Set Overview
  2. Investigator(s)
  3. Theory of Measurements
  4. Equipment
  5. Data Acquisition Methods
  6. Observations
  7. Data Description
  8. Data Organization
  9. Data Manipulations
  10. Errors
  11. Notes
  12. Application of the Data Set
  13. Future Modifications and Plans
  14. Software
  15. Data Access
  16. Output Products and Availability
  17. References
  18. Glossary of Terms
  19. List of Acronyms
  20. Document Information

1. Data Set Overview:

Data Set Identification:

Bowen Ratio Surface Flux: KSU (FIFE).
(Bowen Ratio Surface Flux Observations (KSU)).

Data Set Introduction:

The Bowen Ratio Surface Flux Observations (KSU) Data Set contains the fluxes of net radiation, latent heat and sensible heat measured at selected sites within the FIFE area. The Bowen ratio stations measured the soil heat flux as well.

Objective/Purpose:

The combined aim of the surface flux group was to use a network of ground based observing systems to measure fluxes of heat, water vapor and radiation at a number of points within the FIFE study area.

Summary of Parameters:

Latent heat flux, net radiation, sensible heat flux, soil heat flux, incoming diffuse solar radiation, incoming solar radiation, outgoing solar radiation, soil temperature, rainfall, Bowen ratio, wind speed, wind direction, air temperature, vapor pressure.

Discussion:

Surface flux measurements were made at selected sites within the FIFE area. The major data collection effort was conducted in 1987 when 16 stationary sites were equipped with Bowen ratio equipment that was operated by several different groups. In 1988 and 1989, Bowen ratio surface flux stations were installed at 12 and 19 locations, respectively. Each surface flux station was capable of measuring the fluxes of net radiation, latent heat and sensible heat. The Bowen ratio stations measured the soil heat flux as well.

The surface flux and micrometeorological measurements available in this data set were collected from 23 locations with 27 site identifiers from 1987 through 1989. Thirteen of these locations were instrumented with stationary bowen ratio systems which collected daily measurements for months. These systems were all located in the northwest quadrant of the FIFE study area within the Konza Prairie Natural Research Area. Ten locations were instrumented in 1987 for a few days at a time with a portable Bowen ratio system. This roving system visited all but the southeast quadrant of the FIFE study area.

Related Data Sets:

FIS Data Base Table Name:

SURFACE_FLUX_30MIN_DATA.

2. Investigator(s):

Investigator(s) Name and Title:

Dr. Ghassem Asrar (formerly at KSU)
NASA Headquarters

Dr. Ed Kanemasu (formerly at KSU)
Dept. of Agronomy University of Georgia

Title of Investigation:

Assessing the effects of annual burning and topography on the surface energy exchanges.

Contact Information:

Contact 1:
Dr. Ghassem Asrar
NASA Headquarters
Washington, DC
Telephone: (202) 453-1720

Contact 2:
Dr. Ed Kanemasu
University of Georgia
Griffin, GA
Telephone: (404) 228-7272
Email: ekanema@griffin.uga.edu

Requested Form of Acknowledgment.

The Bowen Ratio Surface Flux Observations (KSU) obtained by Kansas State University were collected under the direction of Drs. G. Asrar and E. Kanemasu. The contribution of these data is appreciated.

3. Theory of Measurements:

The components of the energy balance were determined with the Bowen Ratio Energy Balance (BREB) method. The BREB is a combination of the transport and the energy balance equations. The Bowen ratio, B {a ratio of the transport or gradient equations of sensible heat, H and latent heat, E} is given by:

B = H / E. (1). Where: H = -rho.c(p).K(h). dT/dz

E = -(rho.epsilon / P) l(v).K(v). de/dz

where symbols are defined as: e = Air vapor pressure
epsilon = Ratio of the molecular weights of wet and dry air
c(p) = Specific heat of air
K(h) = Eddy diffusivity for heat
K(v) = Eddy diffusivity fro water vapor
p = Atmospheric pressure
rho = Air density
T = Air temperature
z = Height or depth
l(v) = Latent heat of vaporization

Substituting (1) in the energy balance equation (2) yields the BREB (3). Q is net radiation and G is soil heat flux density.

Q + G + H + E = 0 (2). In this system surface-air interface is considered as a closed system. Any energy flux coming in is considered positive and going out is negative. E = -(Q + G) / (1 + B) (3).

4. Equipment:

Sensor/Instrument Description:

For more information on the instrumentation used to collect these data, see Gay and Greenberg 1985.

Collection Environment:

Ground-based.

Source/Platform:

Ground.

Source/Platform Mission Objectives:

The principal reason to collect these data was to measure the fluxes of sensible and latent heat using the Bowen ratio-energy balance technique.

Key Variables:

Latent heat flux, net radiation, sensible heat flux, surface soil heat flux, incoming solar radiation, photosynthetically active radiation, Bowen ratio, wind speed, soil temperature, air temperature, and vapor pressure.

Principles of Operation:

The Bowen Ratio (BR) system used in this study employed dual psychrometer heads mounted on mechanical exchange systems to eliminate sensor biases (see Gay and Greenberg 1985, Fritschen and Simpson 1989).

Each BR system calculated Beta from mean values of the vertical gradients of temperature (T) and vapor pressure (e) over the 30 minute averaging period and with the known surface pressure (P) and psychrometeric constant (gamma):

Beta = gamma (DELTA(T') / DELTA(e)) P / P(o) Where P(o) is the reference pressure used in gamma.

The BR system used in this study obtaining ground flux by using heat flux panels that were inserted below the surface (nominally 5 cm, to avoid radiative contamination) to obtain the soil flux (G1). Above this critical level, soil temperature probes were inserted to enable the calculation of upper layer heat storage (G2), using a heat capacity (Cs) approach (see Kanemasu et al. 1992).

Sensor/Instrument Measurement Geometry:

Not available at this revision.

Manufacturer of Sensor/Instrument:

Sonic anemometers:

Campbell Scientific
P.O. Box 551
Logan UT 84321

and

Kaijo Denki Co., Ltd.
No. 19.1 - Chrome Kanda-Nishikicho
Chiyoda-Ku
Tokyo 101, Japan.

Fine-wire thermocouple:

Campbell Scientific, Inc.
P. O. Box 551
Logan, UT 84321.

Lyman-alpha Hygrometer:

Atmospheric Instrumentation Research, Inc.
1880 South Flatiron Court
Boulder, CO 80301.

Soil heat transducer:

Radiation & Energy Balance Systems, Inc. (REBS)
P.O. Box 15512
Seattle, WA 98115-0512.

Pyranometer:

Eppley Laboratories
Newport, RI.

Net radiometer:

Radiation & Energy Balance Systems, Inc. (REBS)
P.O. Box 15512
Seattle, WA 98115-0512.

Quantum sensor:

LI-COR, Inc.
4421 Superior Street
P.O. Box 4425
Lincoln, NE 68504.

Psychrometer:

EnviroMet Instrument Company
90 Calle Encanto
Tucson, AZ 85716.

Cup anemometer:

Cayuga Development
Ithaca, NY.

Data logging system:

IBM.

Calibration:

A net radiometer calibration was accomplished using a transfer pyheliometer standard on loan from the Solar Energy Research Institute.

Specifications:

Not available at this revision.

Tolerance:

Not available at this revision.

Frequency of Calibration:

Several of the radiometers were calibrated by the shading technique and compared over the succeeding 24 hour period using data collected every 5 minutes. In 1989, a two day period was set aside for flux comparisons.

Other Calibration Information:

Soil heat flux plates were calibrated in several laboratories under different conditions.

5. Data Acquisition Methods:

The data were acquired by a sensor system which is designed to retrieve all major components of the surface energy budget along with a large set of measured and derived parameters describing the dynamical, thermodynamical, hydrological, and radiative properties of the ground surface and atmosphere surface layer.

Sampling, recording, and near real-time processing of the data were done with a microcomputer.

6. Observations:

Data Notes:

Not available.

Field Notes:

Not available at this revision.

7. Data Description:

Spatial Characteristics:

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.

Spatial Coverage:

These data were collected at the following locations within the FIFE study area. Stations that have the same GRID ID are located within 100 meters of each other. The stations whose GRID IDs end with ROV were equipped with a portable bowen ratio system which visited the location for only a few days. All other stations were equipped with stationary systems which spent many months at the location.

GRID_ID    STN_ID   LATITUDE    LONGITUDE   NORTHING   EASTING    ELEV (ft.)
--------   ------   --------    ---------   ---------  --------   -----
1478-ROV     79     39 06 15    -96 26 56    4331216    720613     350
1816-BRK    802     39 05 59    -96 35 32    4330410    708225     345
1916-BRK    902     39 05 55    -96 35 30    4330282    708259     351
1916-ROV     70     39 05 56    -96 35 30    4330296    708263     340
1935-BRK    812     39 05 49    -96 32 58    4330195    711927     425
2132-BRK*     6     39 05 36    -96 33 23    4329774    711336     405
2133-BRK     60     39 05 34    -96 33 15    4329720    711521     405
2133-BRK    806     39 05 34    -96 33 12    4329726    711604     443
2330-BRK    908     39 05 22    -96 33 35    4329314    711066     424
2516-BRK     14     39 05 12    -96 35 38    4328956    708102     405
2655-ROV     78     39 04 58    -96 30 08    4328712    716057     365
2831-ROV     71     39 04 55    -96 33 32    4328497    711147     445
2915-BRK     12     39 04 47    -96 35 42    4328167    708028     415
3128-BRK    808     39 04 32    -96 33 52    4327780    710683     433
3129-BRK      8     39 04 30    -96 33 51    4327702    710711     430
3129-BRK    912     39 04 33    -96 33 47    4327822    710820     431
3479-ROV     77     39 04 02    -96 26 49    4327137    720894     420
3317-BRK    910     39 04 22    -96 35 24    4327395    708485     427
3317-BRK    810     39 04 24    -96 35 25    4327463    708463     420
3409-BRK    814     39 04 18    -96 36 32    4327244    706850     420
3414-BRK     10     39 04 19    -96 35 51    4327286    707854     410
4268-ROV     76     39 03 15    -96 28 27    4325623    718576     445
4439-ROV     73     39 03 07    -96 32 28    4325218    712794     445
4609-ROV     74     39 03 02    -96 36 41    4324895    706705     390
6912-ROV     75     39 00 29    -96 36 21    4320180    707308     385
6942-ROV     72     39 00 23    -96 32 04    4320158    713497     415  
GRID_ID     SLOPE    ASPECT (Deg.)
--------    -----    ------
1478-ROV
1816-BRK      2        N
1916-BRK      2        N
1916-ROV 
1935-BRK     20        N
2132-BRK
2133-BRK
2133-BRK     14        S
2330-BRK      5        E
2516-BRK
2655-ROV
2831-ROV
2915-BRK
3128-BRK      5       SE
3129-BRK
3129-BRK     14        E
3479-ROV
3317-BRK     15        W
3317-BRK     13        W
3409-BRK     12        E
3414-BRK
4268-ROV
4439-ROV
4609-ROV
6912-ROV
6942-ROV

Note: Site 6 was instrumented only during IFC-1. The instrumentation at this location was moved to site 60 for IFC's 2-4.

Spatial Coverage Map:

Not available.

Spatial Resolution:

These are point data except that the Bowen ratio flux instruments effectively sample fluxes from an area about 100 meters upwind of the sensors.

Projection:

Not available.

Grid Description:

Not available.

Temporal Characteristics:

Temporal Coverage:

Surface flux data in this data set were collected from May 29, 1987 through August 13, 1989. During this period there are three periods of extensive measurement; May 29 through August 13, 1987, April 27 through September 15, 1988, and July 22 through August 13, 1989. During this overall time period there are 298 days of data.

Temporal Coverage Map:

Not available.

Temporal Resolution:

The data values are 30 minute averages of the measured values; sampling was performed at 15 second intervals.

Measurements are daily from May 29 - September 22, 1987; October 2 - 19, 1987; April 27 - June 3, 1988; June 15 - August 8, 1988; August 27 - September 15, 1988; and July 22 - August 13, 1989. There are no measurements between these periods.

Data Characteristics:

The SQL table definition for this data table is found in the SF_30MIN.TDF file located on FIFE CD-ROM Volume 1. The following chart lists only those variables that are contained in the data set described here.


Parameter/Variable Name
Parameter/Variable Description Range Units Source


SITEGRID_ID This is a FIS grid location code. Site grid codes (SSEE-III) give the south (SS) and the east (EE) cell number in a 100 x 100 array of 200 m square cells. The last 3 characters (III) are an instrument identifier.
STATION_ID The station ID designating the location of the observations.
OBS_DATE The date of the observations, in the format (DD-mmm-YY).
OBS_TIME The time that the observation was [GMT] taken, in GMT. The format is HHMM.
LATENT_HEAT_FLUX The latent heat flux, the flux of [Watts] the energy due to the evaporation [meter^-2] of water.
NET_RADTN The net radiation, including both [Watts] downward and upward energy. [meter^-2]
SENSIBLE_HEAT_FLUX The sensible heat flux, the flux of [Watts] the energy due to temperature [meter^-2] differences.
SOIL_HEAT_FLUX The surface soil heat flux, the flux [Watts] of energy into the soil. [meter^-2]
DIFFUSE_SOLAR_RADTN_DOWN The downward (incoming) diffuse [Watts] solar radiation. [meter^-2]
SOLAR_RADTN_DOWN The downward (incoming) solar [Watts] radiation. [meter^-2]
SOLAR_RADTN_UP The upward (outgoing) solar [Watts] radiation. [meter^-2]
PAR_DOWN The downward (incoming) photo- [Watts] synthetically active radiation (PAR). [meter^-2]
PAR_UP The upward (outgoing) photo- [Watts] synthetically active radiation (PAR). [meter^-2]
SOIL_TEMP_0_TO_25MM The soil temperature recorded [degrees somewhere between 0 and 25 mm in depth. Celsius] At Sitegrid 2133-BRK, this is an average from 0 to 75 mm.
SOIL_TEMP_25MM_TO_5CM The soil temperature recorded [degrees somewhere between 25 mm and 5 cm in depth. Celsius] At Sitegrid 2133-BRK, this is an average from 0 to 75 mm.
SOIL_TEMP_5_TO_10CM The soil temperature recorded [degrees somewhere between 5 and 10 cm in depth. Celsius] At Sitegrid 2133-BRK, this is an average from 0 to 75 mm. For 1988 data it is at 8 cm.
SOIL_TEMP_10_TO_20CM The soil temperature recorded [degrees somewhere between 10 and 20 cm in depth. Celsius] At Sitegrid 2133-BRK, this is at 11 cm.
SOIL_TEMP_20_TO_50CM The soil temperature recorded [degrees somewhere between 20 and 50 cm in depth. Celsius] Sitegrid 2133-BRK: 50 cm, 2516-BRK: 50 cm, 2915-BRK: 30 cm, 3129-BRK: 21 cm, 3414-BRK: 50 cm.
RAINFALL The amount of rainfall in this 30 minutes. [mm]
BOWEN_RATIO The Bowen Ratio, the ratio of the SENSIBLE_HEAT_FLUX to the LATENT_HEAT_FLUX.
WIND_SPEED The average wind speed in this 30. [meters] minutes [sec^-1]
WIND_DIR The average wind direction in this [degrees 30 minutes. from North]
AIR_TEMP_HIGH The air temperature at the higher [degrees level. This is the higher of the movable Celsius] sensor arms.
DELTA_TEMP The difference in air temperature between [degrees the higher and lower level (AIR_TEMP_HIGH Celsius] - AIR_TEMP_LOW).
VAPOR_PRESS_HIGH The vapor pressure at the higher level. [kiloPascals] This is the higher of the movable sensor arms.
DELTA_VAPOR_PRESS The difference in the vapor pressure [kiloPascals] between the higher and lower level (VAPOR_PRESS_HIGH - VAPOR_PRESS_LOW).
FIFE_DATA_CRTFCN_CODE * The FIFE Certification Code for the data, in the format: CGR (Certified by Group), CPI (Certified by PI), CPI-??? (CPI - questionable data).
LAST_REVISION_DATE in the format (DD-MMM-YY).

Footnotes:

* 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.

** There are several missing value indicators in each column. The values may be positive or negative 9.9, 9.99, 99.99, 999, 999.99, 9999, or 99999.99.

Sample Data Record:

The following sample record contains all fields in the surface flux record but only those fields that are described here (i.e., reported by G. Asrar and E. Kanemasu) contain data.

SITEGRID_ID   STATION_ID   OBS_DATE    OBS_TIME    LATENT_HEAT_FLUX
-----------   ----------   ---------   ---------   ----------------
1816-BRK         802       28-MAY-88     1215           -99
1816-BRK         802       28-MAY-88     1245          -102
1816-BRK         802       28-MAY-88     1315          -144
1816-BRK         802       28-MAY-88     1345          -178
NET_RADTN   SENSIBLE_HEAT_FLUX   SOIL_HEAT_FLUX   DIFFUSE_SOLAR_RADTN_DOWN
---------   ------------------   --------------   ------------------------
29             50                 20                    53
100            -12                 14                    79
206            -70                  7                   118
264            -89                  3                   130
SOLAR_RADTN_DOWN   SOLAR_RADTN_UP   SOLAR_RADTN_NET   SOLAR_RADTN_DOWN_SDEV
----------------   --------------   ---------------   ---------------------
111              43
206              74
347             108
422             122
SOLAR_RADTN_UP_SDEV    PAR_DOWN      PAR_UP     SURF_ALBEDO
-------------------    ----------   ----------  -----------
234.62        16.08
437.61       31.64
735.12       51.35
907.22       60.69
LONGWAVE_RADTN_DOWN   LONGWAVE_RADTN_UP   LONGWAVE_RADTN_NET
-------------------   -----------------   ------------------
BB_TEMP_LONGWAVE_DOWN   BB_TEMP_LONGWAVE_UP   TOTAL_RADTN_DOWN
---------------------   -------------------   ----------------
TOTAL_RADTN_UP   SOIL_HEAT_FLUX_0_TO_5CM   SOIL_HEAT_FLUX_5_TO_10CM
--------------   -----------------------   ------------------------
SOIL_HEAT_FLUX_10_TO_20CM   HEAT_STORAGE   SOIL_WATER_POTNTL_0_TO_5CM
-------------------------   ------------   --------------------------
SOIL_WATER_POTNTL_5_TO_20CM   SURF_RADIANT_TEMP   SURF_RADIANT_TEMP_SDEV
---------------------------   -----------------   ----------------------
SOIL_TEMP_0_TO_25MM   SOIL_TEMP_25MM_TO_5CM   SOIL_TEMP_5_TO_10CM
-------------------   ---------------------   -------------------
18.82
18.66
18.46
18.27
SOIL_TEMP_10_TO_20CM   SOIL_TEMP_20_TO_50CM    RAINFALL    BOWEN_RATIO
--------------------   --------------------   ----------   -----------
0          -.503
0           .119
0           .484
0           .501
WIND_SPEED    WIND_DIR    WIND_SPEED_MIN   WIND_SPEED_MAX   WIND_SPEED_SDEV
----------   ----------   --------------   --------------   ---------------
4.3        169
4.8        170
4.9        177
4.6        180
WIND_DIR_SDEV   TIME_WIND_SPEED_MIN   TIME_WIND_SPEED_MAX
-------------   -------------------   -------------------
TIME_WIND_DIR_MIN   TIME_WIND_DIR_MAX   WIND_SPEED_HOR_MEAN
-----------------   -----------------   -------------------
WIND_SPEED_LAT_MEAN   WIND_SPEED_VERT_MEAN   WIND_SPEED_HOR_SDEV
-------------------   --------------------   -------------------
WIND_SPEED_LAT_SDEV   WIND_SPEED_VERT_SDEV   AIR_TEMP_LOW   AIR_TEMP_HIGH
-------------------   --------------------   ------------   -------------
18.5
20
21.6
22.2
AIR_TEMP_OTHER   AIR_TEMP_MEAN   AIR_TEMP_MEAN_SDEV   AIR_TEMP_OTHER_SDEV
--------------   -------------   ------------------   -------------------
DELTA_TEMP   WET_BULB_TEMP_LOW   WET_BULB_TEMP_HIGH   VAPOR_PRESS_LOW
----------   -----------------   ------------------   ---------------
.14
-.05
-.27
-.36
VAPOR_PRESS_HIGH   VAPOR_PRESS_MEAN   VAPOR_PRESS_SDEV   REL_HUMID_LOW
----------------   ----------------   ----------------   -------------
1.21
1.26
1.32
1.38
REL_HUMID_HIGH   REL_HUMID_SDEV   SURF_AIR_PRESS   FRICTION_VELOC
--------------   --------------   --------------   --------------
W_T_MEAN      W_E_MEAN    CO2_CONTENT   OZONE_CONTENT   CO2_CONTENT_SDEV
----------   ----------   -----------   -------------   ----------------
OZONE_CONTENT_SDEV     CO2_FLUX   OZONE_FLUX   FIFE_DATA_CRTFCN_CODE
------------------    ----------  ----------   ---------------------
CPI
CPI
CPI
CPI
LAST_REVISION_DATE
------------------
01-NOV-89
01-NOV-89
01-NOV-89
01-NOV-89

8. Data Organization:

Data Granularity:

These are point data except that the Bowen ratio flux instruments effectively sample fluxes from an area about 100 meters upwind of the sensors. Surface flux data in this data set were collected from May 29, 1987 through August 13, 1989.

A general description of data granularity as it applies to the IMS appears in the EOSDIS Glossary.

Data Format:

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 begin 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, and principal investigator name.

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.)

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.

9. Data Manipulations:

Formulae:

Not available at this revision.

Derivation Techniques and Algorithms:

Not provided by Principal Investigator.

Data Processing Sequence:

Processing Steps:

Not available at this revision.

Processing Changes:

Not available at this revision.

Calculations:

Special Corrections/Adjustments:

Not available at this revision.

Calculated Variables:

Not available at this revision.

Graphs and Plots:

None.

10. Errors:

Sources of Error:

Not available at this revision.

Quality Assessment:

It was recognized early in the study that standardizations of "constant" (e.g., physical constants of the air, psychrometric constant, etc.), methods of computation, integration and reporting time, etc. were necessary. These were agreed upon in planning sessions. Preliminary data sets were compared among stations and instruments from different manufacturers for estimating net radiation, soil heat flux, water vapor density, temperature, solar radiation, and wind speed, it was necessary to have confidence that differences in observations were due to site differences and not due to instrumentation.

Data Validation by Source:

The Hydrological Sciences Branch at NASA Goddard Space Flight Center was given the responsibility to compare flux data from all flux stations. This served two purposes: 1) as a data quality check, and 2) a as preliminary analysis of site differences.

Confidence Level/Accuracy Judgment:

The following are the best estimates of accuracy for a single flux estimate:

Net radiation: +/- 4 to 7%

Soil heat flux: +/- 30%

Latent heat flux: +/- 15 to 20 % or +/-30 W m^-2, whichever is larger

Sensible heat flux: +/- 15 to 20 % or +/-30 W m^-2, whichever is larger

None of these estimates addresses the variability of flux estimates from site-to-site.

Measurement Error for Parameters:

Not available at this revision.

Additional Quality Assessments:

Several of the key surface flux parameters have undergone extensive intercomparison and examination for spikes in the data. These data have also been checked for an imbalance in the energy equation. Details of these analyses are described in the Surface Flux Baseline 1992 document on FIFE CD-ROM Volume 1.

FIS staff applied a general QA procedure to some of the fields in this data set 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 numerical field. Inconsistencies and problems found in the QA check are described is the Known Problems with the Data Section.

Data Verification by Data Center:

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.

11. Notes:

Limitations of the Data:

Not available.

Known Problems with the Data:

Wind Speed values greater than 500 m/s, were reported on July 1, 1988 and July 2, 1988, at station 814 (3409-BRK).

Air temperatures measured by the upper arm of the Bowen ratio instrument are greater than 200 deg C, on July 4, 1988 at station 810 (3317-BRK), and greater than 100 deg C, on August 9, 1988 and August 10, 1988, at station 812 (1935-BRK).

Different missing values are used within each column. They may be positive or negative 9.9, 9.99, 99.99, 999.99, 9999, or 99999.99.

The missing value indicators in the following fields may have been inadvertently converted to 1000. Use these data with caution.

         Name                     Name
------------------------   -------------------
DIFFUSE_SOLAR_RADTN_DOWN   TOTAL_RADTN_DOWN
SOLAR_RADTN_DOWN           TOTAL_RADTN_UP
SOLAR_RADTN_UP             HEAT_STORAGE
SOLAR_RADTN_NET            RAINFALL
SOLAR_RADTN_DOWN_SDEV      WIND_DIR_MIN
SOLAR_RADTN_UP_SDEV        WIND_DIR_MAX
LONGWAVE_RADTN_DOWN        CO2_CONTENT
LONGWAVE_RADTN_UP          O3_CONTENT
LONGWAVE_RADTN_NET         CO2_STDEV
BB_TEMP_LONGWAVE_DOWN      O3_STDEV
BB_TEMP_LONGWAVE_UP

Usage Guidance:

Note that sitegrid location 2132 (old station 6) was only used during IFC-1 (May-June, 1987). This was a slope site with serious difficulties, and most observations, including the Bowen ratio instruments, were moved between IFC-1 and IFC-2 to a level site on top of the ridge. This level top location is sitegrid 2133 (old station 60). Therefore, one should not attempt to construct a single continuous sequence of surface flux data from these data.

(Note that FIFE Information System staff attempted, to the best of their ability, to maintain the distinction between sites 6 and 60. This was not always easy to apply in the field, and many investigators referred to this general location as "site 6" throughout 1987 and to some extent 1989. Some data may have been submitted with the wrong site identifier by an investigator and slipped into the final data set collection. Be cautious in using data from these sites, and evaluate the accompanying documentation carefully.)

Any Other Relevant Information about the Study:

Not available at this revision.

12. Application of the Data Set:

Not available.

13. Future Modifications and Plans:

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.

14. Software:

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.

15. Data Access:

Contact Information:

ORNL DAAC User Services
Oak Ridge National Laboratory

Telephone: (865) 241-3952
FAX: (865) 574-4665

Email: ornldaac@ornl.gov

Data Center Identification:

ORNL Distributed Active Archive Center
Oak Ridge National Laboratory
USA

Telephone: (865) 241-3952
FAX: (865) 574-4665

Email: ornldaac@ornl.gov

Procedures for Obtaining Data:

Users may place requests by telephone, electronic mail, or FAX. Data is also available via the World Wide Web at http://daac.ornl.gov.

Data Center Status/Plans:

FIFE data are available from the ORNL DAAC. Please contact the ORNL DAAC User Services Office for the most current information about these data.

16. Output Products and Availability:

The Bowen Ratio Surface Flux Observations (KSU) data are available on FIFE CD-ROM Volume 1. The CD-ROM filename is as follows:

\DATA\SUR_FLUX\30_MIN\GRIDxxxx\YyyMmm\ydddgrid.BRK or \DATA\SUR_FLUX\30_MIN\GRIDxxxx\Yyyyy\ydddgrid.BRK

Where xxxx is the four digit code for the location within the FIFE site grid, yy is the last two digits of the year (e.g., Y87 = 1987), yyyy is the four digits of the century and year (e.g., Y1987 = 1987), mm is the month of the year (e.g., M12 = December), and ddd is the day of the year, (e.g., 061 = sixty-first day in the year). 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: ydddgrid.sfx, where grid is the four-number code for the location within the FIFE site grid, y is the last digit of the year (e.g., 7 = 1987, and 9 = 1989), and ddd is the day of the year. The filename extension (.sfx), identifies the data set content for the file (see the Data Characteristics Section) and is equal to .BRK for this data set.

17. References:

Satellite/Instrument/Data Processing Documentation.

Gay, L.W. and R.J. Greenberg. 1985. The AEET battery-powered Bowen ratio system. Proc. 17th Conf. Agric. and Forest Meteorol. pp. 181-182., Am. Meteor. Soc. Boston, MA.

Field, R.T., L.J. Fritschen, E.T. Kanemasu, E.A. Smith, J.B. Stewart, S.B. Verma and W.P. Kustas. 1992. Calibration, comparison and correction of net radiometer instruments used during FIFE. J. Geophys. Res. 97(D17):18,681-18,695.

Journal Articles and Study Reports.

Baldocchi, D.D., B.B. Hicks, and T.P. Meyers. 1988. Measuring biosphere atmosphere exchanges of biologically related gases with micrometeorological methods. Ecology. 69:1,331-1,340.

Businger, J.A. 1986. Evaluation of the accuracy with which dry deposition can be measured with current micrometeorological techniques. J. Clim. and Appl. Meteorol. 25:1,100-1,124.

Fritschen, L.J., and J.R. Simpson. 1989. Surface energy and radiation balance systems: General description and improvements. J. Appl. Meteorol. 28:680-689.

Fritschen, L.J, .P. Qian, E.T. Kanemasu, D. Nie, E.A. Smith, J.B. Stewart, S.B. Verma and M.L. Wesely. 1992. Comparison of Surface flux measurement systems used in FIFE 1989. J. Geophys. Res. 97(D17):18,697-18,713.

Kanemasu, E.T., S.B. Verma, E.A. Smith, L.J. Fritschen, M. Weseley, R.T. Field, W.P. Kustas, H. Weaver, J.B. Stewart, R. Gurney, G. Panin and J.B. Moncrieff. 1992. Surface flux measurements in FIFE: An Overview. J. Geophys. Res. 97(D17):18.547-18,555.

Nie, D., and E.T. Kanemasu. 1989. Comparison of net radiation on slopes. In: Proc. 19th Conf. Agric. and Forest Meteorol. Charleston, SC, Am. Meteor. Soc. Boston, MA.

Nie, D., E.T. Kanemasu, L.J. Fritschen, H.L. Weaver, E.A. Smith, S.B. Verma, R.T. Field, W.P. Kustas, and J.B. Stewart. 1992. An intercomparison of surface energy flux measurement systems used during FIFE 1987. J. Geophys. Res. 97(D17):18,715-18,724.

Tanner, C.B. 1960. Energy balance approach to evapotranspiration from crops. Soil Sci. Soc. Amer. Proc. 24:1-9.

Verma, S.B. 1990. Micrometeorological methods for measuring surface fluxes of mass and energy. Remote Sensing Reviews. 5:99-115.

Wesely, M.L., D.H. Lenschow, and O.T. Denmead. 1989. Flux measurement techniques. In: Global Tropospheric Chemistry-Chemical Fluxes in the Global Atmosphere. pp. 31-46. National Center for Atmospheric Research. Boulder, CO. 107 pp.

Archive/DBMS Usage Documentation.

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.

18. Glossary of Terms:

A general glossary for the DAAC is located at Glossary.

19. List of Acronyms:

BPI Byte per inch BREB Bowen Ratio Energy Balance CCT Computer Compatible Tape DAAC Distributive Active Archive Center EOSDIS Earth Observation System Data and Information System FIS FIFE Information System HFT Heat Flux Thermometer IFOV Instantaneous Field of View LAI Leaf area index Mbps Megabyte per second ORNL Oak Ridge National Laboratory PAMS Portable Automatic Mesonet REBS Radiation and Energy Balance Systems URL Uniform Resource Locator

A general list of acronyms for the DAAC is available at Acronyms.

20. Document Information:

April 28, 1994 (citation revised on October 15, 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 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.

Document Review Date:

October 14, 1996.

Document ID:

ORNL-FIFE_SF30_BRK.

Citation:

Cite this data set as follows:

Asrar, G., and E. Kanemasu. 1994. Bowen Ratio Surface Flux: KSU (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/21. 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).

Document Curator:

DAAC Staff

Document URL:

http://daac.ornl.gov