Source code for pyseaflux.auxiliary_equations

Additional equations

Not necessarily linked to the marine carbonate system, but are

import numpy as np

[docs]def pressure_height_correction(pres_hPa, tempSW_C, sensor_height=10.0, checks=True): """Returns exact sea level pressure if the sensor is measuring at height Args: pres_hPa (array): Pressure in kiloPascal measured at height tempSW_C (array): Temperature of the seawater in deg C sensor_height (float, optional): the height of the sensor above sea level. Can be negative if you want to convert SLP to sensor height pressure. Defaults to 10.0. Returns: array: height corrected pressure """ from numpy import nanmedian if checks: if nanmedian(tempSW_C) > 270: raise ValueError("Temperature is not in Celsius") if nanmedian(pres_hPa) < 10: raise ValueError("Pressure is not in hPa") T = tempSW_C + 273.15 # temperature in Kelvin P = pres_hPa * 100 # pressure in Pascal # Correction for pressure based on sensor height R = 8.314 # universal gas constant (J/mol/K) M = 0.02897 # molar mass of air in (kg/mol) - Wikipedia # Density of air at a given temperature. Here we assume # that the air temp is the same as the intake temperature d = P / (R / M * T) g = 9.8 # gravity in (m/s2) h = -sensor_height # height in (m) # correction for atmospheric press_height_corr_hpa = (P - (d * g * h)) / 100.0 return press_height_corr_hpa
[docs]def temperature_correction(temp_in, temp_out): """pCO2 correction factor for temperature changes Calculate a correction factor for the temperature difference between the intake and equilibrator. This is based on the empirical relationship used in Takahashi et al. 1993. .. math:: pCO_2^{Tout} = pCO_2^{Tin} * T^{factor} Args: temp_in (array): temperature at which original pCO2 is measured (degK or degC) temp_out (array): temperature for which pCO2 should be represented Returns: array: a correction factor to be multiplied to pCO2 (unitless) References: Takahashi, Taro et al. (1993). Seasonal variation of CO2 and nutrients in the high-latitude surface oceans: A comparative study. Global Biogeochemical Cycles, 7(4), 843–878. """ # see the Takahashi 1993 paper for full description Ti = temp_in To = temp_out factor = np.exp(0.0433 * (To - Ti) - 4.35e-05 * (To ** 2 - Ti ** 2)) return factor