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Home > NDACC Data > NDACC Data Formats > NDACC Ames Additional Considerations

NDACC Ames Additional Considerations

Within the general format structure, certain issues arise as to whether further standardization is possible as to reporting units, the resolution of the data and the format specifications themselves. Toward resolution of these points a meeting was convened on July 19, 1991 with representatives of the above groups along with a small number of instrument representatives. The results of these deliberations are delineated below.

FORMAT CHOICES

Format 1010
- Ground based Total Column measurements:
- UV/Vis measurements
- FTIR measurements
- UVB measurements
- Dobson/Brewer measurements

Format 2110
- Ground based Vertical Profiles
- Remote Profiles from Balloons

Format 2160
- Rawinsonde, Ozonesonde Balloons

 

GENERAL CONSIDERATIONS

  • With the exception of ozonesonde data, all files should contain data representing an integer multiple of months.
  • Atmospheric Levels; Resolution and Time Averaging: All data should be reported in the natural sequence and resolution dictated by the signal to noise ratio. The report should specify the averaging time interval.
  • Ancillary Data: Other measurements or assumed information (eg climatology) used to correct, process or interpret the primary data should be reported.
  • Error Parameters: The systematic and random errors should be reported separately when appropriate. Systematic errors are those which limit the absolute accuracy whereas random errors are those which limit the precision of the measurement. When only one error is reported it should be the combined error. The order of reporting should be parameter, error, parameter, error ...
  • Calibration: The date when a calibration parameter is changed should be reported along with a description of the change.
  • Geophysical Information: The altitude above mean sea level should be reported and, where appropriate, the solar zenith angle for the measurement.

 

VERTICAL PROFILE DATA

Vertical Profile Measurement Units

  • Concentration molecules/cm**3
  • Mixing Ratio ppmv
  • Temperature degrees K
  • Aerosol scattering ratio
  • Wind m/s
  • Pressure hectopascals
  • Altitude meters above mean sea level, or meters above site
When using meters above site, the altitude of the site above mean sea level must be reported as an auxiliary variable. The lowest altitude (highest pressure) should be first in the sequence.

Vertical Profile Independent Variables

The unbounded independent unbounded variable will be an altitude parameter, if altitude in meters, or pressure in hectopascals whichever is the natural parameter for the instrument. The bounded independent variable will be day number of the reported year (line 7) in format xxx.xx which allows for multiple measurements on the same day. Day 1 begins at 00 hours UT on January 1. Thus, an observation at 06 UT on January 1 would be reported as day 1.25. Reported time is the beginning of the observation.

Vertical Profile Primary Variables

As the number of parameters will be variable, the sequence is free with the particulars specified in the descriptive part of the format. As stated above, we recommend that the report have the lowest altitude (highest pressure) first in sequence and that the data be provided as parameter, systematic error, random error...

Vertical Profile Auxiliary Variables

  • Number of altitudes (pressures) reported
  • Year (Use the four digit year 199x instead of two digit 9x so as to avoid future confusion with the standard two digit missing value indicator 99 and the actual year 99).
  • Month
  • Day (UT)
  • Hour (UT)
  • Minute (UT)
  • Averaging time of presented data: xx.xx hours
  • Latitude of observation: +/ 90.00 degrees
  • Longitude of observation: 0.00 to 360.00 degrees east
  • Solar zenith angle (if appropriate): degrees
  • Altitude of site above mean sea level: meters

 

TOTAL COLUMN DATA

Total Column Measurement Units

  • All Gases (including ozone) molecules/cm**2
The notion to depart from the current Dobson Unit to molecules/cm **2 was not done lightly and was decided upon on the basis that consistency of units in today's scientific consideration of multiple parameters outweighed the continued use of the specialized Dobson Unit.
  • Aerosols integrated backscatter and/or optical depth

Total Column Measurement Independent Variables
The unbounded independent variable will be day number of the reported year (line 7) in format xxx.xx which allows for multiple measurements on the same day. Day 1 begins at 00 hours UT on January 1. Thus, an observation at 06 UT on January 1 would be reported as day 1.25. Reported time is the beginning of the observation.

Total Column Measurement Primary Variables

Both slant path and vertical column measurements should be archived. For NDSC purposes these should be in a single file. Recognizing that the number of species reported will be variable from site to site, the number and sequence of reported parameters is free with the particulars specified in the descriptive part of the format. We recommend, however, that the overall sequence be parameter, systematic error, random error; parameter, systematic error, random error etc.

Total Column Measurement Auxiliary Variables

  • Year (Use the four digit year 199x instead of two digit 9x so as to avoid future confusion with the standard two digit missing value indicator 99 and the actual year 99).
  • Month Number
  • Day (UT)
  • Hour (UT)
  • Minute (UT)
  • Latitude of observation: +/ 90.00
  • Longitude of observation: 0.00 to 360.00 degrees east
  • Altitude of site above mean sea level: meters
  • Solar zenith angle: degrees
  • Averaging time of presented data: xx.xx hours
  • Air temperature
  • Surface pressure


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Page last modified: Friday, 24-Jan-2014 22:25:01 UTC