olsen_randerson package

Temporal downscaling of fluxes following Olsen and Randerson (2004).

olsen_randerson.NEP_TO_GPP_FACTOR = 2

Conversion factor to estimate GPP from NEE

The downscaling needs GPP, but often only NEE is available. This describes how to turn the latter into an estimate of the former.

olsen_randerson.Q10 = 1.5

The \(Q_{10}\) value used in the Olsen and Randerson downscaling.

It is the factor by which the respiration increases when the temperature increases by ten degrees.

olsen_randerson.T0 = 30

Baseline temperature for Olsen-Randerson downscaling.

Should be near the center of the temperature range.

olsen_randerson.olsen_randerson_gpp_once(flux_gpp, par)[source]

Downscale the GPP following Olsen and Randerson (2004).

Parameters
flux_gppnp.ndarray[…]

The GPP to downscale. Units must include time in denominator. GPP is defined to be greater than or equal to zero.

parnp.ndarray[N, …]

PAR at downscaled frequency. Will be used for the GPP downscaling. PAR is defined to be greater than or equal to zero.

Returns
flux_gppnp.ndarray[N, …]

The downscaled GPP

References

Olsen, Seth C. and James T. Randerson, 2004. “Differences between surface and column atmospheric CO2 and implications for carbon cycle research,” Journal of Geophysical Research: Atmospheres vol. 109, no. D2, D02301. doi:10.1029/2003JD003968.

Examples

>>> olsen_randerson_gpp_once(np.array(2.), np.array([0., 1, 1]))
array([0., 3., 3.])
>>> olsen_randerson_gpp_once(np.array(2.), np.array([0., 2, 2]))
array([0., 3., 3.])
olsen_randerson.olsen_randerson_once(flux_nep, temperature, par)[source]

Perform the Olson Randerson downscaling.

Parameters
flux_nepnp.ndarray[…]

Biogenic NEP, usually at monthly timescale. Units must include time in the denominator.

temperaturenp.ndarray[N, …]

Temperature in Celsius, at the downscaled resolution. Units are expected to be degrees Celsius.

parnp.ndarray[N, …]

PAR, at the downscaled resolution. PAR is defined to be greater than or equal to zero.

Returns
flux_neenp.ndarray[N, …]

The downscaled NEP.

References

Olsen, Seth C. and James T. Randerson, 2004. “Differences between surface and column atmospheric CO2 and implications for carbon cycle research,” Journal of Geophysical Research: Atmospheres vol. 109, no. D2, D02301. doi:10.1029/2003JD003968.

Examples

>>> time = np.arange(0, 3, .1)
>>> par = -np.cos(2 * np.pi * time)
>>> par[par < 0] = 0
>>> temperature = 10 - 10 * np.cos(2 * np.pi * time)
>>> # First item in row alternates between midnight and noon
>>> olsen_randerson_once(np.array(5), temperature, par)
array([-3.20043607, -3.4581163 , -4.2353102 ,  4.10768819, 18.33559721,
       23.70071827, 18.33559721,  4.10768819, -4.2353102 , -3.4581163 ,
       -3.20043607, -3.4581163 , -4.2353102 ,  4.10768819, 18.33559721,
       23.70071827, 18.33559721,  4.10768819, -4.2353102 , -3.4581163 ,
       -3.20043607, -3.4581163 , -4.2353102 ,  4.10768819, 18.33559721,
       23.70071827, 18.33559721,  4.10768819, -4.2353102 , -3.4581163 ])
olsen_randerson.olsen_randerson_resp_once(flux_resp, temperature)[source]

Downscale the respiration following Olsen and Randerson (2004).

Parameters
flux_respnp.ndarray[…]

The original respiration fluxes to downscale. Units must include time in the denominator. Respiration fluxes are defined to be greater than or equal to zero.

temperaturenp.ndarray[N, …]

The temperature at the downscaled frequency. Expected units are degrees Celsius.

Returns
flux_respnp.ndarray[N, …]

The downscaled respiration fluxes.

References

Olsen, Seth C. and James T. Randerson, 2004. “Differences between surface and column atmospheric CO2 and implications for carbon cycle research,” Journal of Geophysical Research: Atmospheres vol. 109, no. D2, D02301. doi:10.1029/2003JD003968.

Examples

>>> olsen_randerson_resp_once(np.array(19./12.), np.array([0., 10., 20.]))
array([1.  , 1.5 , 2.25])