TITLE: INDOEX: Maldives KCO Chemistry Carbon Monoxide (Lobert) 

Contact/Author:

J.M. Lobert
Center for Clouds, Chemistry and Climate
Scripps Institution of Oceanography
University of California, San Diego
9500 Gilman Drive
La Jolla, CA 92093-0221
USA

Email: jlobert@ucsd.edu; j.lobert@bigfoot.com 
Telephone: +1 858 822 0297 
Fax: +1 858 534 4922

URL: http://www-indoex.ucsd.edu/observatory/


1.0 DATA SET OVERVIEW:
 
The data set contains daily, mean surface carbon monoxide (CO) data 
collected at the Kaashidhoo Climate Observatory (KCO) during the 
INDOEX IFP January to March 1999. Data coverage is (inclusive) 
01 January 1999 to 31. March 1999.  KCO is located at 4.9664 degrees N and 
73.4657 degrees E, the CO air inlet was mounted about 14 m above sea level 
(mean elevation of the site is about 0.5-1.0 m) on the top of the observation 
tower. KCO local time is UT + 5 hours. For website info, see authors.

This is version 1.1 of the data set, revised on 26 June 2000 due to a 
change in the calibration scale of NOAA/CMDL (P. Novelli, unpublished).


2.0 INSTRUMENT DESCRIPTION: 

A non-dispersive, infrared absorption analyzer model 300 (Advanced 
Pollution Instrumentation) was used with a mean flow of 700 cc/min 
and an inline, Nafion-type gas dryer, span/zero calibration option 
and modified instrument software. Calibration was carried out with 
a NOAA/CMDL standard.  For a more detailed description of this instrument 
and the experiment, see Cogan and Lobert (1998) or Lobert and Harris (2000), 
respectively, or contact the author.


3.0 DATA COLLECTION AND PROCESSING: 

Ambient air was continuously drawn through the instrument using 6.3 mm OD 
Decoron tubing. The instrument calculated one, ten and 30-minute means, 
the latter were alternating with a 20-minute zero-check. Lowest data 
resolution is hence one 30 minute mean every 50 minutes. Daily means and 
statistics published here were calculated from 30-minute means. Higher 
(30 min) or lower (weekly, monthly) resolution data are available upon 
request from the author.

Data intercomparison with NOAA/CMDL flasks taken at the same site yielded 
an agreement within 10%, a similar agreement was found with data taken aboard 
the R/V Ron Brown on 05 March 1999.


4.0 DATA FORMAT: 

All files are in plain, tab-delimited ASCII text.

Data headers as they appear in the files:

DayTimeSpread	DOY1999	Mean_CO	StdDev	StdErr	Median_CO	N	Max_CO	Min_CO	Percentile75	Percentile25

Jan01_36161	Jan01_1	ppb	ppb	ppb	ppb	30min_means	ppb	ppb	ppb	ppb

Header explanation:
"DayTimeSpread" is the Date and Time (Universal time) in spreadsheet format, 
noon of 01 January is 36161.5.

"DOY1999" is the decimal day of year 1999, noon of 01 January is 1.5

Mean_CO is the mean, daily CO mixing ratio in ppb (parts per billion, 
10^-9 mole per mole of air.


5.0 DATA REMARKS: 

An overview figure of the data has been provided (KCO.Surface.CO.jpg).


6.0 REFERENCES:

1) Mark Cogan and Jurgen M. Lobert, Instrumentation For Trace-Level 
Measurement of Carbon Monoxide in Pristine Environments, Proceedings 
of the 43rd Annual ISA Analysis Division Symposium, Volume 31, p. 229, 
ISBN 1-55617-664-3, Instrument Society of America, Research Triangle 
Park, NC, April 26-29, 1998.

2) Jurgen M. Lobert and Joyce M. Harris, Trace Gases and Air Mass Origin 
over Kaashidhoo, Indian Ocean. Submitted to JGR.