Air-sea CO2 flux

This function calculates the air-sea CO2 fluxes from seawater and atmospheric CO2 partial pressure, temperature, salinity and wind speed.
Syntax

[F_CO2, dpCO2]=FCO2(pCO2_agua, pCO2_atm,T,S,u)

pCO2_agua= seawater pCO2 (uatm)
pCO2_atm= atmospheric pCO2 (uatm)
T= Temperature (Celsius)
S= Salinity
u = Wind speed (m/s)

It uses the gas transfer constantes of Waninkhoff, (1992), and the CO2 solubility constants of Weiss (1974)

Wanninkhof, R. (1992), Relationship Between Wind Speed and Gas Exchange Over the Ocean, J. Geophys. Res., 97(C5), 7373-7382.

Weiss, R. F. (1974), Carbon dioxide in water and seawater: the solubility of a non-ideal gas, Marine Chemistry, 2(3), 203-215.