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Site Averaged AMS Data: 1987 (Betts)


The Site Averaged AMS Data: 1987 (Betts) data set contains the site-averaged product of the Portable Automatic Meteorological Station (AMS) data acquired during the 1987-1989 FIFE experiment. Data are in 30-minute time intervals in 1987.

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:


Data Set Introduction:

This data set is a site-averaged product of the Portable Automatic Meteorological Station (AMS) data acquired during the 1987-1989 FIFE experiment. The raw data have been extensively cleaned and edited before the site average was generated. The center of the FIFE 15x15 km site is close to 39.05þN, 96.53þW.

The 3 years of data were acquired and processed separately over a period of several years; and as a result there are a few differences in the 87 product and in the underlying methodology.

The 1987 data was downloaded piecemeal (by 2400 baud modem!) from the FIFE information center, edited and merged. Subsequently the 1988 data was retrieved from the FIFE CD ROM Volume1; and the 1989 data was retrieved directly from the Oak Ridge DAAC. As our computers have improved by more than an order of magnitude in speed and disc space during the processing period, the 1989 data received a more uniform processing than the 1987. All the originating data however should correspond to that in the group 8, "Surface Meteorological Measurements (SUR_MET)" or FIFE CD-ROM Volume 1, dated May 22, 1994, FIS Data Base Table "AMS_DATA_8x".


Information not available.

Summary of Parameters:

Air Temperature, Atmospheric Pressure, Longwave Radiation, Precipitation Rate, Reflectance, Shortwave Radiation, Soil Temperature, Solar Radiation, Surface Temperature, and Surface Wind Speed/Direction.


Information not available.

Related Data Sets:

2. Investigator(s):

Investigator(s) Name and Title:

Alan K. Betts and John H. Ball
Atmospheric Research
Telephone: (802) 483-2087
Fax: (802) 483-6167

Title of Investigation:

FIFE Follow-On.

Contact Information:

ORNL DAAC User Services Office
Oak Ridge National Laboratory
Telephone: 1-(865)-241-3952
Fax: 1-(865)-574-4665

Requested Form of Acknowledgment.

You may use these files freely. Please send Alan Betts ( an e-mail if you do, so he can notify you of any updates. Please notify both Alan Betts and the ORNL DAAC of any errors you find.

This data processing was supported by NASA under Contract NAS5-32356 to Alan Betts, and an acknowledgment of the years of work that went into the production of these files would be appreciated in publications based substantially on them.

The FIFE CD-ROM can be cited as D. E. Strebel, D. R. Landis, K. F. Huemmrich, and B. W. Meeson (1994), Collected Data of The First ISLSCP Field Experiment, Vol. 1: Surface Observations and Non-Image Data Sets.

3. Theory of Measurements:

Information not available.

4. Equipment:

Sensor/Instrument Description:

Collection Environment:



Meteorological Station.

Source/Platform Mission Objectives:

Information not available.

Key Variables:

Information not available.

Principles of Operation:

Information not available.

Sensor/Instrument Measurement Geometry:

Information not available.

Manufacturer of Sensor/Instrument:

Information not available.


Information not available.

5. Data Acquisition Methods:

Information not available.

6. Observations:

Information not available.

7. Data Description:

Spatial Characteristics:

The FIFE site, 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, U.S.A. The northwest corner of the area has UTM coordinates of 4,334,000 Northing and 705,000 Easting in UTM Zone 14.

The center of the FIFE 15 x 15 km site is close to 39.05þN, 96.53þW.

Spatial Coverage:

The distribution of stations during the data collection period is listed below. Only 12 sitegrids were instrumented with the AMS equipment in 1987. At two of these sitegrids additional instruments measuring radiation were also installed.


     0847-SAM       52       2428-PAM       3        4609-PAM        17
0847-SDC       29       3221-PAM       7        6469-PAM        23
1563-PAM       27       4168-SAM      51        6912-PAM        19
2123-SAM        5       4168-SDC      25        8639-SAM        21
2139-PAM       31       4439-PAM      11

Spatial Coverage Map:

Not available.

Spatial Resolution:

These are point data.


Information not available.

Grid Description:

Information not available.

Temporal Characteristics:

Temporal Coverage:

This data set contains data from May 1, 1987 through December 31, 1987.

Temporal Coverage Map:

Not available.

Temporal Resolution:

The time interval of the year is broken down into 30 minute intervals. There is one variable sample at each 30 minute time interval so in a LEAP (NOTE 1988) there are 366 x 48 = 17658 time intervals. This field in the database in named "YSq#" (Yearly Sequence #) and makes a convenient linear time scale; in addition to day and UTC.

Data Characteristics:

Parameter/Variable Name

Table 1. contains a summary of the variables in this data set.

Table 1. Variable Description

Variable Name  Long Name               SAS Type  Description

1  Ysq_no                              8         "Time interval of the year broken
into 30-minute intervals"
2  date        OBS_DATE                8         "Observation date (mm/dd/yyyy)"
3  Jul_Date                            8         "Julian date (day of year 1-366)"
4  utc                                 8         "Decimal time"
5  P           ATMOSPHERIC_PRESSURE    8         "Average atmospheric pressure 
6  P_k                                 8         "Number of sites included in 
atmospheric pressure average"
7  P_s                                 8         "Atmospheric pressure standard 
8  T           DRY_BULB_TEMPERATURE    8         "Average dry bulb temperature 
(degrees C)"
9  T_k                                 8         "Number of sites included in 
average dry bulb temperature 
10 T_s                                 8         "Dry bulb temperature standard 
11 Tw          WET_BULB_TEMPERATURE    8         "Average wet bulb temperature 
(degrees C)"
12 Tw_k                                8         "Number of sites included in 
average wet bulb temperature 
13 Tw_s                                8         "Wet bulb temperature standard 
14 Rain30      RAINFALL_RATE(*)        8         "Average rainfall rate for 
30-minutes (Rain30)"
15 Rain30_k                            8         "Number of sites included in 
average 30 minute rainfall rate
16 Rain30_s                            8         "Standard deviation of average 30 
minute rainfall rate (Rain30)"
17 U           U_COMPNT_WIND_VELOC     8         "Average U component of wind 
velocity (m/s)"
18 U_k                                 8         "Number of sites included in 
average U 
component wind velocity (U)"
19 U_s                                 8         "Standard deviation of U 
component wind velocity (U)"
20 V           V_COMPNT_WIND_VELOC     8         "Average V component of wind 
velocity (m/s)"
21 V_k                                 8         "Number of sites included in 
average V component wind 
velocity (V)"
22 V_s                                 8         "Standard deviation of V 
component wind velocity (V)"
23 Tsurf       SURF_TEMP               8         "Average surface temperature 
(degrees C)"
24 Tsurf_k                             8         "Number of sites included in 
average surface temperature 
25 Tsurf_s                             8         "Standard deviation of surface 
temperature (Tsurf)"
26 Tsoil10     SOIL_TEMP_10CM          8         "Average soil temperature at 10 
cm (degrees C)"
27 Tsoil10k                            8         "Number of sites included in 
average soil temperature at 10 
cm (Tsoil10)"
28 Tsoil10s                            8         "Standard deviation of soil 
temperature at 10 cm (Tsoil10)"
29 Tsoil50     SOIL_TEMP_50CM          8         "Average soil temperature at 50 
cm (degrees C)"
30 Tsoil50k                            8         "Number of sites included in 
average soil temperature at 50 
cm (Tsoil50)"
31 Tsoil50s                            8         "Standard deviation of soil 
temperature at 50 cm (Tsoil50)"
32 SolDn       TOTAL_INCIDENT_RADTN    8         "Average total incident radiation 
33 SolDn_k                             8         "Number of sites included in 
total incident radiation average 
34 SolDn_s                             8         "Standard deviation of average 
total incident radiation 
35 SolRef      SHORTWAVE_SOLAR_REFL    8         "Average shortwave solar 
reflectance (W/m2)"
36 SolRef_k                            8         "Number of sites included in 
average shortwave solar 
reflectance (SolRef)"
37 SolRef_s                            8         "Standard deviation of average 
shortwave solar reflectance 
38 Rnet        NET_RADTN               8         "Average net radiation (W/m2)"
39 Rnet_k                              8         "Number of sites included in 
average net radiation (Rnet)"
40 Rnet_s                              8         "Standard deviation of average 
net radiation  (Rnet)"
41 IRDn        INCIDENT_LONGWAVE_RADTN 8         "Average incident longwave 
radiation (W/m2)"
42 IRDn_k                              8         "Number of sites included in 
average incident longwave 
radiation (IRDn)"
43 IRDn_s                              8         "Standard deviation of average 
incident longwave radiation 
44 Q                                   8         "Average mixing ratio"
45 Q_k                                 8         "Number of sites included in 
average mixing ratio (Q)"
46 Q_s                                 8         "Standard deviation of average 
mixing ratio (Q)"
47 ToCldoct                            8         "Average total cloud cover 
48 HiCldoct                            8         "Average high cloud cover 
49 TimePhot                            8         "Time of day sky photographs were 
50 MF_cld10                            8         "Reported cloud cover from 
Marshall Field (tenths)"
51 obs_time                            8         "Observation time (hhmm)"

(*) The FIS rainfall rate is in mm/5mins, and was multiplied by 6 to give mm in 30 mins.

In 1987 there are also four cloud variables;

ToCld_octas cloud sky cover in eights.
HiCld_octas cloud sky cover in eights.
TimePhoto the time of day of sky photograph.
Mf_cld_tenths reported cloud cover from Marshall Fieldi, in tenths.

Unit of Measurement:

Refer to the Table 1 Description.

Data Source:

Meteorological Station.

Data Range:

Information not available.

Sample Data Record:

Ysq_no  date     Jul_Date   utc     P     P_k  P_s    T      T_k  T_s     Tw 
Tw_k  Tw_s  Rain30  Rain30_k  Rain30_s  U     U_k  U_s    V    V_k  V_s  Tsurf  Tsurf_k  Tsurf_s  Tsoil10  Tsoil10k  Tsoil10s  Tsoil50  Tsoil50k  Tsoil50s  
SolDn  SolDn_k  SolDn_s  SolRef  SolRef_k  SolRef_s  Rnet  Rnet_k  Rnet_s  IRDn 
IRDn_k  IRDn_s  Q    Q_k  Q_s  ToCldoct  HiCldoct  TimePhot  MF_cld10  obs_time

5761   05/01/1987   121     0.25   961.92  9   2.44   24.34   8   0.37   16.51 
8     0.19    0     9         0       -4.95   9    1.37   2.88  9   0.99  22.83
8        1.85     22.53        8       2.47     15.28      6        1.71 
153.94   2       7.64     34.28    9        4.05    26.97    9     18.22    .
0        .     9.24   8   0.24   .         .         .          .       0015
5762   05/01/1987   121     0.75   961.98  9   2.45   23.28   9   0.45   16.12 
9     0.17    0     9         0       -4.43   9    0.92   3.09  9   0.43  20.82
8        1.26     22.25        8       2.46     15.34      6        1.71
68.53    2       2.67     16.44    9        1.57    -11.88   9      7.9     . 
0        .     9.2    9   0.18   .         .         .          .       0045
5763   05/01/1987   121     1.25   961.99  9   2.45   21.84   9   0.45   15.62 
9     0.21    0     9         0       -3.69   9    0.95   2.38  9   0.33  18.6 8
1.17    21.5         9       2.56     15.31      6        1.72
15.4     2       0.69     4.01     9        1.18    -33.24   9      2.84    . 
0        .     9.19   9   0.18   .         .         .          .       0115
5764   05/01/1987   121     1.75   962.07  9   2.45   20.7    9   0.39   15.07 
9     0.27    0     9         0       -3.72   9    1.2    2.13  9   0.46  17.24 
8        1.2      21.19        9       2.54     15.33      6        1.72
0        2       2.12     0        9        0.98    -41.78   9      2.23    . 
0        .     9.02   9   0.21   .         .         .          .       0145

8. Data Organization:

Data Granularity:

         File names          size (bytes) 
         fifams87.dat        2493717      

Data Format:

This data set is a time series of 30 minute average variables for the periods May 1, 1987- Dec 31, 1987 (50 fields; 14 variables (mean , SD, and count; plus 4 cloud fields); date (2), UTC, year sequence #.)

9. Data Manipulations:

Information not available.

10. Errors:

Sources of Error:

Information not available.

Quality Assessment:

Data Validation by Source:

Information not available.

Confidence Level/Accuracy Judgment:

Most variables are continuous for all but a few short periods. There is no radiation data for an extended period of one month from April 11 through May 10, 1988 because the instruments were being calibrated. However, other than this period, Rnet is available about 99% of the time. IRDn is missing for three extended time intervals and may be of questionable value for much of the time that it is available.

Data Filters and Cleaning:

A set of filters was applied to reject bad data points and help to identify lines of bad data (such as produced by electrical noise). Table 2 summarizes these filters. Scanning the data and nulling out obvious erroneous data manually effected further data editing. Some bad values will, however, have slipped through, these can often be identified by a large value of the standard deviation.

                      Table 2. Data filters

Variable       Max/Min (1988)           Filter Range
P              999.94/938.29            930 to 1000
T              37.94/-23.17             -30 to 45
Tw             36.01/-22.43             -30 to 40 & (Tw-T)0.05
Rain30         7.75/0                   
U              31.20/-27.56             
V              22.29/-17.86             
Tsurf          54.76/-39.34             -50 to 60
Tsoil10        39/-2.85                 -10 to 50
Tsoil50        26/1.38                  -5 to 40
SolDn          1034.71/-4.88            -5 to 1200
SolRef         543,45/-4.93             -5 ot 600
Rnet           8.39.52/-87.36           -98 to 1000
IRDn           498.52/143.60            100 to 600
Q              N/A (calculated)              

Each variable (for all sites), together with the site-average and standard deviation were then examined graphically and manually (and iteratively) edited to eliminate bad data; and generate a cleaned-up site average for each variable. Some such as temperature and wet-bulb temperature were examined in pairs. Some bad data has escaped this process; often this is indicated by a solitary extreme standard deviation.


We did not interpolate variables at a site before averaging; but we have interpolated most site-average variables to fill gaps (where these are small <6 hours) to reduce the burden on modelers. Gaps of more than a day have generally not been interpolated; although we have filled a few missing days temperature profiles with a simple and obvious sawtooth patterns (in 1988 and 1989). Some missing Net radiation values at night have been set to -30 Wm-2. In 1988 and 1989 SolDn and SolRef have been set to 0 (zero) between sun set and sun rise.

INTERPOLATED DATA IS EASILY IDENTIFIED. If the count on a variable is zero the data has been interpolated.

Measurement Error for Parameters:

Information not available.

Additional Quality Assessments:

Information not available.

Data Verification by Data Center:

Information not available.

11. Notes:

Limitations of the Data:

Not available.

Known Problems with the Data:

Information not available.

Usage Guidance:

Information not available.

Any Other Relevant Information about the Study:

Original 1987 AMSDOC.txt

This is the documentation from the original May 26 - Oct 16 1987 site average data set from the FIFE CD-ROM. We include it for its remarks on the cloud data fields; and formula used for mixing ratio q, as we have not reprocessed this period, except for rain and IRDN.

FIFE-87 compacted surface data set. (Betts and Ball, 1992)
Rev. Date: December 11, 1992

This data set contains FIFE-site averages derived from (ten) AMS stations (data every 30 minutes), together with cloud data from two sources, from May 26 - Oct 16, 1987.

The raw data for these files came from the FIS Data Base tables AMS_DATA_87 and CLOUD_CAMERA_DATA. The MF_Cld field was obtained independently from the hourly cloud observations of Marshall AAF, KS, approximately 12 km west of the FIFE site.

Data Processing

Surface Portable Automated Meteorological Stations.

These were PAM-II stations supplied by the National Center for Atmospheric Research (NCAR), with pressure (PS), temperature (T)and wet-bulb (TW) temperature sensors mounted at 2 m and an anemometer at 5.4 m, as well as ground temperature sensors at 10 cm (T1soil) and 50 cm (T2soil) below the surface.

Each station measured surface skin temperature (TSfc) with a downward looking radiometer, net radiation (RNet) with a net radiometer, measured reflected solar radiation (SolRef) and recorded rainrate and accumulation from a tipping bucket raingauge. A subset of stations (2 before August, 10 1987 and then 4) measured incoming solar radiation (SolDn), and longwave radiation (LWDN) (2 before October, 1987, and then 4). The archive data uses NCAR's calibrations of the instruments.

Data Filters

A set of filters was applied to reject bad data points and identify lines of bad data (such as produced by electrical noise). These are shown in Table 87-1.

                             Table 87-1

Variable       May 26-Jun 24  Jun 25-Aug21   Aug 22-Oct 16

SolDn          -5 to 1200     -5 to 1200     -5 to 1200
SolRef         -5 to 250      -5 to 250      -5 to 250
RNet           -98 to 1000    -98 to 1000    -98 to 800
TSfc            0 to 55       10 to 55      -10 to 35
TSoil10         9 to 30       19 to 30        9 to 21
TSoil50         11 to 30      19 to 30       11 to 19

T and TW were filtered to eliminate any data where Twas less than TW. The data was scanned for low values of surface pressure.

For both the radiation and thermodynamic data, further data editing was done by scanning the data and nulling out obvious erroneous data manually. Some bad values will however have slipped through.

The mixing ratio (Q) was calculated from TW and PS (surface pressure) as follows:

QW = 622 / (0.1631 * PS * exp(-17.67 * TW / (TW + 243.5)) - 1) Q = QW - (1006 / 2501) * (T - TW)

Data Averaging

All the station data that passed this editing were averaged for each date and time to give a site average, a standard deviation, and a count of stations in the average. The center of the FIFE area is close to 39.05þN, 96.53þW.

The standard deviation is between sites, which are located at different altitudes, on different types and slopes of terrain, different soils etc. Isolated high standard deviations probably indicate an erroneous value that has not been filtered, although in some variables such as SolDn or RNet, they may be caused by more extensive cloud over a few sites. We have not included a standard deviation for LWDN, since there are only 2 sites with this measurement for much of the time.

Cloud data

Two fields relating to daytime cloud cover for total cloud and high cloud (in octas) are from the archive of digitized photographic data (from Ann Henderson-Sellers). They are not 30 min. averages. The instantaneous digitized mean cloud cover from each single frame was simply assigned to the 30 min. time block in which it was taken. Since photos were typically every 40 min., every fourth time had no photo. A further field indicates the exact time of a photo. The MF_Cld field was obtained independently from the hourly cloud observations of Marshall AAF, KS, approximately 12 km west of the FIFE site. This data set is in tenths cloud cover, estimated by observer.

12. Application of the Data Set:

Information not available.

13. Future Modifications and Plans:

There are no plans to revisit this data; but let us know of errors.

14. Software:

Information not available.

15. Data Access:

Contact Information:

ORNL DAAC User Services
Oak Ridge National Laboratory
Telephone: (865) 241-3952
FAX: (865) 574-4665

Data Center Identification:

ORNL Distributed Active Archive Center
Oak Ridge National Laboratory
Telephone: (865) 241-3952
FAX: (865) 574-4665

Procedures for Obtaining Data:

Users may place requests by telephone, electronic mail, or FAX. Data is also available via the World Wide Web at

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:

This data set is available online via the World Wide Web at, or telnet 6493 ( 6493), or 12345 ( 12345)

17. References:

Betts and Ball, 1996: FIFE surface climate and site-average data set 1987-1989, Submitted to J. Atmos. Sci. (3rd FIFE special issue)

Betts, A.K., J.H. Ball, and A.C.M. Beljaars, 1993: Comparison between the land surface response of the European Centre model and the FIFE-1987 data. Q.J.R.M.S., 119, 975-1001.

Betts, A.K. and J.H. Ball, 1994: Budget analysis of FIFE-1987 sonde data. J.G.R., 99, 3655-3666.

Betts, A.K. and J.H. Ball, 1995: The FIFE surface diurnal cycle climate. J.G.R. 100, 25679-25693.

Betts A. K. And J. H. Ball, 1997: FIFE surface climate and site-average dataset: 1987-1989. (FIFE special issue 3 J.Atmos. Sci. in press)

Strebel, D. E., D. R. Landis, K. F. Huemmrich, and B. W. Meeson, 1994: Collected data of the First ISLSCP Field Experiment, in Surface Observations and Non-Image Data Sets., Vol 1, CD-ROM, NASA GSFC, Greenbelt, MD 20771

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

19. List of Acronyms:

ESD Environmental Sciences Division (Oak Ridge National Laboratory) FTP File Transfer Protocol NASA National Aeronautics and Space Administration ORNL Oak Ridge National Laboratories, Oak Ridge, Tennessee, U.S.A. URL Uniform Resource Locator

A general list of acronyms for the DAAC is available at

20. Document Information:

December 4, 1996 (citation revised on October 1, 2002)

Document Review Date:

March 19, 1997

Document ID:



Cite this data set as follows (citation revised on October 1, 2002):

Betts, A. K. 1994. Site Averaged AMS Data: 1987 (Betts). Data set. Available on-line [] from Oak Ridge National Laboratory Distributed Active Archive Center, Oak Ridge, Tennessee, U.S.A. doi:10.3334/ORNLDAAC/88.

Document Curator:

DAAC Staff

Document URL: