Section 30 - Carbon Credits (Carbon Farming Initiative—Estimation of Soil Organic Carbon Sequestration Using Measurement and Models) Methodology Determination 2021 - Mean modelled soil organic carbon stock for each model-validation site in a stratum | Zoe
Carbon Credits (Carbon Farming Initiative—Estimation of Soil Organic Carbon Sequestration Using Measurement and Models) Methodology Determination 2021
30Mean modelled soil organic carbon stock for each model-validation site in a stratum
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30 Mean modelled soil organic carbon stock for each model-validation site in a stratum
Work out the mean modelled soil organic carbon stock for the model-validation sites, in each stratum h (the View image in the official source), in tonnes of soil organic carbon per hectare, using the following equation:
ModSOCi is the modelled soil organic carbon stock for each model-validation site i, from stratum View image in the official source, in tonnes of soil organic carbon per hectare, worked out using Section 29.
31 Working out the soil organic carbon stock of each model-validation site in each layer
(1) The soil organic carbon stock (View image in the official source for each model-validation site i, for the 0-30 cm and 0-x cm layers, in tonnes of organic carbon per hectare, must be worked out under subsection (2) or (3) based on the relationship between:
(a) the mass of oven dry whole soil collected (View image in the official source) for the sample layer (0-30 cm and 0-x cm) worked out in accordance with any requirements in the Supplement, in tonnes of oven dry whole soil per hectare; and
(b) the equivalent soil mass (the ESM) defined for the CEA, given by section 13 of this Schedule, in tonnes of oven dry whole soil per hectare.
Note: The value of n increases with increasing depth such that sub-layer 1 denotes the soil sub-layer including the soil surface and sub-layer n denotes the deepest sub-layer that contributes to equation 94 as required by the Supplement.
View image in the official source is the soil organic carbon stock in a soil sub-layer determined in accordance with any requirements in the Supplement, in tonnes of soil organic carbon per hectare.
View image in the official source is the number of sub-layers progressing incrementally down from the soil surface required to produce a value for View image in the official source that is equal to or exceeds the ESM, given by section 13 of this Schedule, in tonnes of oven dry whole soil per hectare.
View image in the official source is the soil organic carbon stock in a soil sub-layer determined in accordance with any requirements in the Supplement, in tonnes of soil organic carbon per hectare.
View image in the official source is the sum of soil organic carbon stocks in all sub-layers excluding sub-layer n, in tonnes of soil organic carbon per hectare.
View image in the official source is the soil organic carbon stock in the sub-layer n, in tonnes of soil organic carbon per hectare, determined in accordance with any requirements in the Supplement.
ESM is the equivalent soil mass for the CEA where the soil samples were collected given by section 13 of this Schedule, in tonnes of oven dry whole soil per hectare.
View image in the official source is the oven dry mass of whole soil within a sub-layer, in tonnes of oven dry whole soil per hectare, determined in accordance with any requirements in the Supplement.
View image in the official source is the sum of the mass of oven dry whole soil in all sub-layers excluding sub-layer n, in tonnes of oven dry soil per hectare.
View image in the official source is the mass of oven dry whole soil contained in the soil sub-layer n, in tonnes of oven dry soil per hectare, determined in accordance with any requirements in the Supplement.
Note: This section is identical to section 15 in subdivision 2 using the measurement-based approach except that it is applied to only model-validation samples rather than any samples in the CEA (including calibration samples).
32 Mean soil organic carbon stock in a stratum from model-validation samples
Work out the mean soil organic carbon stock for each stratum h (the View image in the official source) in the CEA, in tonnes of soil organic carbon per hectare, using the following equation:
SOCi is the soil organic carbon stock for each sample site i in stratum h , worked out using equation 94 or 95, in tonnes of soil organic carbon per hectare.
Note: This section is identical to section 16 in subdivision 2 using the measurement-based approach except that it is applied to only model-validation samples rather than any samples in the CEA (including calibration samples).
33 Area-weighted mean soil organic carbon stock in a CEA from model-validation samples
Work out the area-weighted mean soil organic carbon stock in the CEA (the View image in the official source), in tonnes of soil organic carbon per hectare, using the following equation:
View image in the official source is the relative area of the CEA covered by stratum h in the CEA, expressed as a proportion of the total CEA area.
View image in the official source is the mean soil organic carbon stock in the stratum h, in tonnes of soil organic carbon per hectare, worked out using equation 96.
Note: This section is identical to section 17 in subdivision 2 using the measurement-based approach except that it is applied to only model-validation samples rather than any samples in the CEA (including calibration samples).
34 Variance of the mean soil organic carbon stock within a stratum from model-validation samples
Work out the variance of the mean soil organic carbon stock for each stratum h in the CEA (the View image in the official source, in (tonnes of soil organic carbon per hectare)2, using the following equation:
SOCi is the soil organic carbon stock for each sample i from stratum h, in tonnes of soil organic carbon per hectare, worked out using equation 94 or 95.
View image in the official source is the mean soil organic carbon stock in the stratum h, in tonnes of soil organic carbon per hectare, worked out using equation 96.
35 Variance of the mean soil organic carbon stock within a CEA from model-validation samples
Work out the variance of the mean soil organic carbon for the CEA (the View image in the official source, in (tonnes of soil organic carbon per hectare)2, using the following equation:
View image in the official source is the relative area of the CEA covered by stratum h in the CEA, expressed as a proportion of the total CEA.
View image in the official source is the variance of the mean soil organic carbon for stratum h, in (tonnes of soil organic carbon per hectare)2, worked out using equation 98.
View image in the official source is number the model-validation samples, with unique modelled carbon stock estimate units (pixels/polygons) collected from the stratum h.
View image in the official source is the area of a unique modelled carbon stock estimate unit (e.g. pixels) for the model-validation samples collected from the stratum h.
Note: The area of a single estimation area (e.g. pixel or polygon) is not counted twice if two sample locations happen to co-locate on the same modelled carbon stock estimate unit (e.g. pixel). At its most simple, this is the fraction of raster cells sampled in a CEA.
38 Area-weighted mean of the modelled carbon stocks at sample sites
Work out the area-weighted mean of the modelled carbon stock from the model-validation sites in the CEA (View image in the official source using the following equation:
View image in the official source is the relative area of the CEA covered by stratum h in the CEA, expressed as a proportion of the total CEA.
ModView image in the official source mean modelled soil organic carbon stock for the model-validation sites, in stratum h, in tonnes of soil organic carbon per hectare, worked out using equation 93.
39 Regression coefficient for the modelled and sampled carbon stocks in the CEA
Work out the regression coefficient (View image in the official source for the modelled and sampled carbon stocks in the CEA using the following equation:
View image in the official source is the modelled soil organic carbon stock for model-validation site i, in tonnes of soil organic carbon per hectare, worked out using equation 91 or 92.
View image in the official sourceis the mean modelled soil organic carbon stock for the model-validation sites, in stratum h, in tonnes of soil organic carbon per hectare, worked out using equation 93.
40 Regression estimate of carbon stocks in the CEA
View image in the official source is the area-weighted mean of the modelled carbon stock from the model-validation sites in the CEA, worked out using equation 102.
41 Variance of the modelled soil organic carbon stock within a stratum
Work out the variance of the mean modelled soil organic carbon for the model-validation sites for each stratum h in the CEA (the View image in the official source, in (tonnes of soil organic carbon per hectare)2, using the following equation:
ModSOCi is the modelled soil organic carbon stock for each sample site i in stratum h, in tonnes of soil organic carbon per hectare, worked out using equation 91 or 92.
View image in the official source is the mean modelled soil organic carbon stock for the model-validation sites for each stratum h, worked out using equation 93.
42 Covariance of the sampled and modelled soil organic carbon stocks in each stratum
Work out the covariance of the sampled and modelled soil organic carbon stocks for each stratum h in the CEA View image in the official source in (tonnes of soil organic carbon per hectare)2, using the following equation:
SOCi is the soil organic carbon stock for each sample i from stratum h, in tonnes of soil organic carbon per hectare, worked out using equation 94 or 95.
View image in the official source is the mean soil organic carbon stock in the stratum h, in tonnes of soil organic carbon per hectare, worked out using equation 96.
ModSOCi is the modelled soil organic carbon stock for each sample site i from stratum h, in tonnes of soil organic carbon per hectare, worked out using equation 91 or 92.
43 Regression estimate of sampling variance of mean carbon stocks within a stratum
Work out the regression estimate of sampling variance of mean carbon stocks for each stratum h in the CEA (the RegView image in the official source for the sampled and modelled carbon stocks in the CEA (tonnes of soil organic carbon per hectare)2, using the following equation:
View image in the official source is the variance of the mean soil organic carbon stock for the stratum h, worked out using equation 98.
View image in the official source is the regression coefficient for the modelled and sampled carbon stocks in the CEA, worked out using equation 103.
View image in the official source is the covariance of the sampled and modelled soil organic carbon stocks in stratum h, worked out using equation 106.
VView image in the official source is the variance of the mean modelled soil organic carbon for the model-validation sites for each stratum h, worked out using equation 105.
44 Regression estimate of sampling variance of mean carbon stocks in the CEA
Work out the regression estimate of sampling variance of mean carbon stocks in the CEA (the RegView image in the official source for the sampled and modelled carbon stocks in the CEA (tonnes of soil organic carbon per hectare)2, using the following equation:
View image in the official source is the relative area of the CEA covered by stratum h in the CEA, expressed as a proportion of the total CEA.
View image in the official source is the regression estimate of sampling variance of mean carbon stocks for stratum h, worked out using equation 107, in (tonnes of soil organic carbon per hectare)2.
45 Degrees of freedom for the regression estimate of sampling variance of mean carbon stocks in the CEA
Work out the degrees of freedom (View image in the official source to use in equation 115 for a given estimation event, using the following equation:
View image in the official source is the relative area of the CEA covered by stratum h in the CEA, expressed as a proportion of the total CEA area.
View image in the official source is the regression estimate of sampling variance of mean carbon stocks for stratum h in the CEA, worked out using equation 106A, in (tonnes of soil organic carbon per hectare)2.
Note 2: Where a CEA contains three strata, equation 109 written in its expanded form, where the subscripts 1, 2, and 3 are used to denote values for stratum 1, stratum 2, and stratum 3, respectively takes the following form:
View image in the official source is the area-weighted mean of the modelled carbon stock from the model-validation sites in the CEA, worked out using equation 102.
Note: This section does not directly inform the net abatement calculations for the CEA directly but rather are calculated for the purposes of model-validation statistics in the Supplement that allow for the use of model-only estimates in other CEAs.
47 Correlation of the sampled and modelled soil organic carbon stocks for the CEA
Work out correlation of the modelled and measured carbon stocks in the CEA (View image in the official source using the following equation:
View image in the official source is the relative area of the CEA covered by stratum h in the CEA, expressed as a proportion of the total CEA.
View image in the official source is the covariance of the sampled and modelled soil organic carbon stocks for each stratum h in the CEA, worked out using equation 106.
View image in the official source is the variance of the mean soil organic carbon for each stratum h, worked out using equation 98, in (tonnes of soil organic carbon per hectare)2.
View image in the official source is the variance of the mean modelled soil organic carbon for the model-validation sites for each stratum h , worked out using equation 105, in (tonnes of soil organic carbon per hectare)2.
Note: This section does not directly inform the net abatement calculations for the CEA directly but rather are calculated for the purposes of model-validation statistics in the Supplement that allow for the use of model-only estimates in other CEAs.
View image in the official sourceis the regression estimate of sampling variance of mean carbon stocks in the CEA for the sampled and modelled carbon stocks in the CEA, worked out using equation 108, in (tonnes of soil organic carbon per hectare)2.
View image in the official sourceis the regression carbon stock estimate for the CEA, worked out using equation 104 in tonnes of soil organic carbon per hectare.
Note: This section does not directly inform the net abatement calculations for the CEA directly but rather are calculated for the purposes of model-validation statistics in the Supplement that allow for the use of model-only estimates in other CEAs.
49 Working out the creditable change in soil organic carbon stock in a CEA for a reporting period
Subject to subsection 10(4) of this Schedule, the creditable change in soil organic carbon in each CEA associated with a specified probability of exceedance for a reporting period (the View image in the official source), between the first estimation event in the CEA (t0 ) and the last estimation event (tx) in the reporting period, in tonnes of soil organic carbon, must be worked out in accordance with this Division.
50 Change in carbon stock between estimation events
Work out the change in soil organic carbon stock for the CEA between the first estimation event (t0 ) and the last estimation event (tx), in the reporting period (the View image in the official source in tonnes of soil organic carbon, using the following equation:
51 Standard error for change in soil organic carbon stock
Work out the standard error of the mean difference between total soil organic carbon stock for the CEA between the first estimation event (t0 ) and the last estimation event (tx), in the reporting period (the View image in the official source), in tonnes of soil organic carbon, using the following equation:
Note 1: The first estimation event must include sampling for consistency with paragraph 5(2)(a) of this Schedule, which requires sampling for the first estimation event.
53 Change in soil organic carbon stock in the CEA with a specified probability of exceedance for a reporting period
Work out the change in soil organic carbon stock for a CEA for a reporting period between the first estimation event and a subsequent estimation event for the reporting period associated with a specified probability of exceedance (the View image in the official source), in tonnes of soil organic carbon, using the following equation:
(a) if the calculation occurs for the first and second estimation events for the CEA—0.25;
Note: The 0.25 multiplier is a temporary discount to the creditable amount of change in soil organic carbon stock due to the use of only 2 estimation events (the effect of climatic influences relative to management-induced changes is assumed to be less influential after three carbon stock estimations and the discount no longer applies). After 3 or more estimations, credits withheld due to the discount will be returned if carbon increases are maintained.