# Underway pCO~2~ Data Reduction Method

Group/PI:

Method of data reduction (Macro, Matlab-routine, manual, etc):

Please describe in bullet form the steps you use to reduce the raw CO2
data.

*EXAMPLE*

*•Manual data reduction*

*•MergeTSG and CO2 data*

*•copy std values to extra sheet*

*•calculate calibration coefficients based on 2^nd^ order polynomial
using cell pressure corrected mole fraction*

*•calculate cell-pressure corrected mole fraction, calculate pre and
post calibrated xCO2 values based on 2^nd^ order polynomials*

*•calculate time weighted xCO2 from pre and post xCO2 in order to
interpolate inbetween standard runs*

*•check and flag bad data*

Which events and ranges produce errors in your routine and/or flag data
as questionable or bad in final results? (check and/or add other)

GPS gaps *bad data*

low seawater flow (define) *0.4 L/min=bad measurement*

low gas flow *40-60=acceptable measurement*

communication error (specify) *no signal from licor=bad measurement*

licor out of range errors (define range): *not considered in 1st
reduction step*

CO2 mV/concentration out of range

H2O mV/concentration out of range

Cell temperature out of range

Cell pressure out of range

EQ temperature out of range (define range): *not considered in 1st
reduction step*

EQ pressure out of range (define range): *not considered in 1st
reduction step*

Coastal limits *not considered in 1st reduction step*

Other

How are your data flags defined?

*based on WOCE sample quality flags*

*1=sample was drawn but analysis not received*

*2=acceptable measurement*

*3=questionable measurement*

*4=bad measurement*

*5=not reported*

*etc.*

Which raw data do you use to calculate pCO2 and fCO2: mV or fitted xCO2?

*Fitted xCO2*

Which calibration interpolation do you use (e.g. linear, polynomial)?
How do you interpolate inbetween standards?

*2^nd^ order polynomial, time-weighted interpolation according to:*

*xCO2~t~ = ( xCO2~pre~ \* (t~post~ -- t) + xCO2~post~ \* (t -- t~pre~))
/ (t~post~ -- t~pre~)*

Quote the references of the calculation methods you use for the
following:

Temperature correction

*Takahashi, 1993*

pH2O calculation

*Weiss et al., 1982*

pCO2/fCO2 calculation

*DOE handbook*

Other references:

Do you eliminate bad raw data values ( e.g Tequil, Salinity) in your
final file or do you use a (-9) default value?

*Eliminate*

Do you retain bad fCO2 values in your final files (with appropriate
flag) or do you eliminate them?

*Eliminate*

Do you interpolate \"input\" values if values are missing or bad? If so,
how and which ones?

*No interpolation*

Do you use averaging and/or despiking routines for input values? If yes,
please detail.

*None*

Do you account for time offset for water transit and equilibration time.
If yes, how?

*No accounting.*

Describe your final data output.

*GROUP/SHIP,CRUISE_DESIGNATION,JD_GMT,DATE_DDMMYYYY,TIME_HH:MM:SS,LAT_DEC_DEGREE,LONG_DEC_DEGREE,xCO2W_PPM,xCO2A_PPM,PRES_EQUIL_hPa,PRES_SEALEVEL_hPa,EqTEMP_C,SST(TSG)\_C,SAL(TSG)\_PERMIL,WATER_FLOW_L/MIN,GAS_FLOW_IR_ML/MIN,TEMP_IR_C,PRES_IR_hPa,SHIP_HEADING_TRUE_DEGREE,SHIP_SPEED_KNOT,WIND_DIR_REL_DEGREE,WIND_SPEED_REL_M/S,fCO2W@SST_uATM,QC_FLAG_WATER,fCO2A_uATM,QC_FLAG_AIR,dfCO2_uATM,FLUORO_uG/L,WIND_SPEED_TRUE_M/S,WIND_DIR_TRUE_DEGREE,AIR_TEMP_C*