d86#

hydrometlib.cosmos.d86(cosmos_vwc, pa, ref_soc, ref_bulkdensity, ref_latticewater, distance)[source]#

Calculate D86 value [cm]

D86 is defined as the depth to which 86% of the detected cosmic ray neutrons had contact with constituents of the soil. It can be calculated at given distances from the Cosmic Ray Neutron Sensor (CRNS).

\[\begin{split}\begin{aligned} \theta_{twe} &= \frac{\theta_v}{100} + \rho_b \, (\theta_{lw} + \theta_{soc}) \\[4pt] F_p &= \frac{0.4922}{0.86 - e^{-p_a / 1013}} \\[4pt] r^{*} &= \frac{r}{F_p} \\[4pt] D_{86} &= \frac{1}{\rho_b} \left[ 8.321 + 0.14249 \left( 0.96655 + e^{-0.01 \, r^{*}} \right) \frac{20 + \theta_{twe}}{0.0429 + \theta_{twe}} \right] \end{aligned}\end{split}\]

where \(\theta_{twe}\) is the total water-equivalent content, \(r\) is distance, \(\rho_b\) is ref_bulkdensity, \(\theta_{lw}\) is ref_latticewater and \(\theta_{soc}\) is ref_soc. The vegetation factor is fixed at 1.

Reference:

Schrön, M., Köhli, M., Scheiffele, L., Iwema, J., Bogena, H. R., Lv, L., Martini, E., Baroni, G., Rosolem, R., Weimar, J., Mai, J., Cuntz, M., Rebmann, C., Oswald, S. E., Dietrich, P., Schmidt, U., and Zacharias, S. Improving calibration and validation of cosmic-ray neutron sensors in the light of spatial sensitivity, Hydrol. Earth Syst. Sci., 21, 5009-5030, https://doi.org/10.5194/hess-21-5009-2017, 2017

Parameters:

  • cosmos_vwc (Expr) – Volumetric Water Content (soil moisture) [%]

  • pa (Expr) – Atmospheric Pressure [hPa]

  • ref_soc (Expr) – Site attribute of reference soil organic carbon [g g-1]

  • ref_bulkdensity (Expr) – Site attribute of reference soil bulk density [g cm-3]

  • ref_latticewater (Expr) – Site attribute of reference lattice water content [g g-1]

  • distance (Expr) – Site attribute - distance away from the CRNS the calculation is valid for [m]

Return type:

Expr

Returns:

Expression or Series calculating d86 [cm]