diff --git a/data/README.md b/data/README.md index 8c43cf5..455fd5d 100644 --- a/data/README.md +++ b/data/README.md @@ -4,11 +4,11 @@ A detailed description of the calibratable parameters is given below. | Parameter name | Units | Physical limits | Range tested for stability | Applies to individual soil layers or entire model domain | Description | | --- | --- | --- | --- | --- | --------------- | -| theta_r | - | 0< theta_r <1,
theta_r < theta_e | 0.01 < theta_e < 0.15 | Soil layer | theta_r is the residual water content, or the minimum volumetric water content that a soil layer can naturally attain. Note that theta_r must be less than than theta_e. | -| theta_e | - | 0 < theta_e < 1,
theta_r < theta_e | 0.3 < theta_e < 0.8 | Soil layer | theta_e is the maximum volumetric water content that a soil layer can naturally attain. Note that theta_e must be greater than theta_r. | -| alpha | 1/cm | alpha > 0 | 0.001 < alpha < 0.3 | Soil layer | alpha is the van Genuchten parameter related to the inverse of air entry pressure. Note that in nature, expected values of alpha are distributed logarithmically, so calibrating on the log of alpha rather than alpha directly is likely a better choice for most calibration algorithms. | -| n | - | n > 1 | 1.01 < n <3 | Soil layer | n is the van Genuchten parameter related to pore size distribution. Note that another commonly reported van Genuchten parameter, m, is related to n via m = 1 - 1/n. We recommend that n > 1.01. Values larger than 3 are acceptable. | -| Ks | cm/h | Ks > 0 | 0.001 < K_s < 100 | Soil layer | Ks is the saturated hydraulic conductivity of a soil. Note that in nature, expected values of Ks are distributed logarithmically, so calibrating on the log of Ks rather than Ks directly is likely a better choice for most calibration algorithms. | +| theta_r | - | 0< theta_r <1,
theta_r < theta_e | 0.01 < theta_r < 0.15 | Soil layer | theta_r is the residual water content, or the minimum volumetric water content that a soil layer can naturally attain. Note that theta_r must be less than than theta_e. This is set per soil layer, in the .dat file in the data directory.| +| theta_e | - | 0 < theta_e < 1,
theta_r < theta_e | 0.3 < theta_e < 0.8 | Soil layer | theta_e is the maximum volumetric water content that a soil layer can naturally attain. Note that theta_e must be greater than theta_r. This is set per soil layer, in the .dat file in the data directory.| +| alpha | 1/cm | alpha > 0 | 0.001 < alpha < 0.3 | Soil layer | alpha is the van Genuchten parameter related to the inverse of air entry pressure. Note that in nature, expected values of alpha are distributed logarithmically, so calibrating on the log of alpha rather than alpha directly is likely a better choice for most calibration algorithms. This is set per soil layer, in the .dat file in the data directory.| +| n | - | n > 1 | 1.01 < n <3 | Soil layer | n is the van Genuchten parameter related to pore size distribution. Note that another commonly reported van Genuchten parameter, m, is related to n via m = 1 - 1/n. We recommend that n > 1.01. Values larger than 3 are acceptable. This is set per soil layer, in the .dat file in the data directory.| +| Ks | cm/h | Ks > 0 | 0.001 < K_s < 100 | Soil layer | Ks is the saturated hydraulic conductivity of a soil. Note that in nature, expected values of Ks are distributed logarithmically, so calibrating on the log of Ks rather than Ks directly is likely a better choice for most calibration algorithms. This is set per soil layer, in the .dat file in the data directory.| | ponded_head_max | cm | ponded_head_max >= 0 | 0 <= ponded_head_max <= 5 | Entire model domain | This is the maximum amount of ponded water that is allowed to accumulate on the soil surface. While stability tests have only included a maximum value of 5 cm, any value greater than or equal to 0 should be acceptable. A common choice will be 0. This parameter can be set in the config file. | | field_capacity_psi | cm | 0 < field_capacity_psi,
field_capacity_psi < wilting_point_psi | 10.3 < field_capacity_psi < 516.6 | Entire model domain | This is the wilting point of the model domain, expressed as a capillary head. Together with wilting_point_psi, the field capacity is used to determine the intensity of the reduction of PET to become AET. The numbers 10.3 cm and 516.6 cm correspond to pressures of 1/100 atm and 1/2 atm of water. Note that the model generally uses absolute values of capillary head; in this case, these limits are absolute values of negative numbers and physically represent unsaturated soil. While field capacity will vary per soil type, we use a single value for the entire model domain, following the method for PET->AET correction used by HYDRUS. This parameter can be set in the config file. |