Redmine 14531

I’m attempting to calculate CO2 flux for Pioneer datasets for an educator tutorial because the calculation currently isn’t working (see my helpdesk ticket #14527). To test my calculation, I used data from 2017 from CE02SHSM-SBD12-04-PCO2AA000, since pco2_co2flux is provided for that dataset. I downloaded data from CE02SHSM-SBD11-06-METBKA000 and used the pco2_co2flux function from ion_functions to calculate co2 flux.

https://github.com/oceanobservatories/ion-functions/blob/master/ion_functions/data/co2_functions.py#L374-L440

Inputs:

pco2w = CE02SHSM-SBD12-04-PCO2AA000 pco2a_a_dcl_instrument_water_recovered partial_pressure_co2_ssw
pco2a = CE02SHSM-SBD12-04-PCO2AA000 pco2a_a_dcl_instrument_air_recovered partial_pressure_co2_atm
u10 = CE02SHSM-SBD11-06-METBKA000 metbk_hourly met_wind10m
t = CE02SHSM-SBD11-06-METBKA000 metbk_a_dcl_instrument_recovered sea_surface_temperature
s = CE02SHSM-SBD11-06-METBKA000 metbk_a_dcl_instrument_recovered met_salsurf

According to the Parameter Function Map from preload, these are the only inputs: {"u10": "PD3092", "pco2w": "PD1002", "s": "PD3077", "pco2a": "PD1003", "t": "PD1056"}. The result I get from the calculation is the opposite of what uFrame provides in the data files. Plot attached (CE02SHSM-SBD12-04-PCO2AA000 system vs calculated CO2 Flux.png) of pco2_co2flux from the system vs. the CO2 Flux I calculated using the same function uFrame is supposed to be using. When I multiply my result by -1 it matches what the system provides.

Also attached is a plot of pCO2 seawater (partial_pressure_co2_ssw) and atmosphere (partial_pressure_co2_atm) in the top panel, and pco2_co2flux from the system in the bottom panel (CE02SHSM-SBD12-04-PCO2AA000 pco2 and flux.png). When pCO2 in the atmosphere is higher than pCO2 in seawater, CO2 flux from ocean to atmosphere should be negative - the flux data downloaded from the system appear to be the opposite.

A participant in an educator workshop calculated CO2 flux independently of the system (using converted MATLAB code) for CE07SHSM-SBD12-04-PCO2AA000 (4/2018 - 4/2019), and also found that flux is negative when pCO2 in the atmosphere is higher than seawater (CE07SHSM-SBD12-04-PCO2AA000 external calculation.png). I recreated his plot using the flux provided by the system, which shows that the flux is largely positive (CE07SHSM-SBD12-04-PCO2AA000 pco2 and flux.png).

I think uFrame is somehow reversing the pco2_co2flux values.

Confirmed: the inputs to the function were reversed. The issue was fixed on 12/11/2019.