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| 
Natal
-CO-
| Observation |
| Category |
: |
Air sampling observation |
| Situation |
: |
ongoing |
| Time zone |
: |
UTC |
| Sampling |
| Sampling height |
: |
|
| Description |
: |
flask |
| Sampling and analysis frequency |
: |
|
| Sampling environment |
: |
|
| Description for sampling analysis |
: |
|
| Instrument and Analysis |
| Measurement method |
: |
GC-HgO |
| Current status and history of instrument |
: |
GC-HgO |
| Description of instrument |
: |
Trace Analytical lnc. |
| Calibration |
| Current scale employed in the measurement |
: |
WMO CO scale |
| Measurement calibration |
: |
|
| Scale and calibration(treasability) |
: |
WMO CO scale |
| Data Processing |
| Measurement unit |
: |
ppb |
| Data processing |
: |
|
| Processing for averaging |
: |
Processing for Monthly Data:
Monthly means are produced for each site by first averaging all valid measurement results in the event file with a unique sample date and time. Values are then extracted at weekly intervals from a smooth curve (Thoning et al., 1989) fitted to the averaged data and these weekly values are averaged for each month to give the monthly means recorded in the files. Flagged data are excluded from the curve fitting process. Some sites are excluded from the monthly mean directory because sparse data or a short record does not allow a reasonable curve fit. Also, if there are 3 or more consecutive months without data, monthly means are not calculated for these months. |
| Data flag |
: |
NOAA ESRL uses a 3-column quality control flag where each column is defined as follows:
[column 1]
REJECTION flag. An alphanumeric other than a period (.) in the FIRST column indicates a sample with obvious problems during collection or analysis. This measurement should not be interpreted.
[column 2]
SELECTION flag. An alphanumeric other than a period (.) in the SECOND column indicates a sample that is likely valid but does not meet selection criteria determined by the goals of a particular investigation.
[column 3]
COMMENT flag. An alphanumeric other than a period (.) in the THIRD column provides additional information about the collection or analysis of the sample.
WARNING: A "P" in the 3rd column of the QC flag indicates the measurement result is preliminary and has not yet been carefully examined by the PI. The "P" flag is removed once the quality of the measurement has been determined.
If both the first and second column contain a period (e.g., "..." and "..I"), the sample is RETAINED.
Flag : Description
[RETAINED]
... : Accepted as background air sample
..I : sample has also been measured by another lab as part of an intercomparison experiment
..C : mixing ratio falls outside of calibration range (see Section ).
..< : first reference sample flagged
..> : second reference sample flagged
[SELECTED]
.X. : determined using a statistical method to be an outlier
.N. : flagged manually as an outlier
NOTE: Some sites known to be heavily impacted by regional pollution are not SELECTED for background conditions. Among these are BAL, BSC, HUN, OBN and TAP.
[REJECTED]
*.. : off-scale or broken flask
W.. : flask type unacceptable for measurement of CO
Z.. : one or more sample aliquots diff by 3 ppb or more
P.. : flasks in pair differ by 3 ppb or more
A.. : rejected due to error in analysis
E.. : sample collected as part of CCG experiment
S.. : sample collected through observatory CO2 analyzer
LLL : Indicates that for the specified site, measurements of this and more recent samples have not yet been evaluated by the PI. |
| Data remarks |
: |
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| Other Information |
| Scientific aim |
: |
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| Reference |
: |
Lang, P.M., L.P. Steele, R.C. Martin, and K.A. Masarie, Atmospheric methane data for the period 1983-1985 from the NOAA/GMCC global cooperative flask sampling network, NOAA Technical Memorandum ERL CMDL-1, 1990a.
Lang, P.M., L.P. Steele, and R.C. Martin, Atmospheric methane data for the period 1986-1988 from the NOAA/CMDL global cooperative flask sampling network, NOAA Technical Memorandum ERL CMDL-2, 1990b.
Novelli, P.C., J.E. Elkins, and L.P. Steele, The development and evaluation of a gravimetric reference scale for measurements of atmospheric carbon monoxide, J. Geophys. Res., 96, 13,109-13,121, 1991.
Novelli, P.C., L.P. Steele, and P.P. Tans, Mixing ratios of carbon monoxide in the troposphere, J. Geophys. Res., 97, 20,731-20,750, 1992.
Novelli, P.C., J.E. Collins, Jr, R.C. Myers, G.W. Sachse, and H.E. Scheel, Reevaluation of the NOAA/CMDL carbon monoxide reference scale and comparisons to CO reference gases at NASA-Langley and the Fraunhofer Institute, 99, 12,833- 12,839, 1994.
Novelli, P.C., K.A. Masarie, and P.M. Lang, Distributions and recent changes in carbon monoxide in the lower troposphere, J. Geophys. Res., 103, 19,1015- 19,033, 1998.
Novelli, P.C., K.A. Masarie, P.M. Lang, B.D. Hall, R.C. Myers, and J.W. Elkins, Re-analysis of tropospheric CO trends: Effects of the 1997-1998 wild fires, J. Geophys. Res., 108, D15 : 4464, doi:10.1029/2002JD003031, 2003. |
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| submitted by Earth System Research Laboratory, NOAA |
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