Data from: Anaerobic digester installation significantly reduces liquid manure management CH4 emissions at a California dairy farm
Data files
Feb 19, 2026 version files 11.55 MB
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All_Instantaneous_Gridded_CH4_Mole_Fraction_Data.csv
11.39 MB
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All_Receptor_Meteorology_and_CH4_Mole_Fraction_Data.csv
37.97 KB
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CARB_Estimates_Comparison.xlsx
15.27 KB
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CH4_Emissions_Normalizations.xlsx
19.34 KB
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CH4_Emissions_Relative_Change_and_Uncertainty_Calculation.xlsx
16.30 KB
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CH4_Emissions_Results.csv
735 B
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CH4_Mole_Fraction_Grid_Cell_Summary.csv
32.84 KB
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README.md
12.75 KB
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Statewide_Upscaling_Dairy_Digesters.xlsx
23.40 KB
Abstract
Anaerobic digesters are expected to significantly reduce CH4 emissions from dairy manure management by capturing them for use as biogas. However, verification of the effectiveness of anaerobic digesters to reduce CH4 emissions has not been conducted at scale in California. We made atmospheric measurements from a mobile platform and used dispersion modeling to estimate CH4 emissions from a liquid manure storage complex at a typical California dairy before and after digester installation across nine field campaigns. We also compared measured emissions reduction to estimates using California Air Resources Board (CARB) inventory methodologies and estimated the statewide impact of emissions reduction by upscaling to planned or completed digester projects. This dataset contains the raw and processed files associated with the results of this study. More details on methodology and the variable definitions can be found in the supporting information documents associated with the manuscript. The CH4 emissions results from dispersion modeling, normalizations, and relative emissions reduction are presented as well as the averaged CH4 mole fraction and associated meterological data for stationary receptor measurements used as inputs to the dispersion model. Instantaneous and grid cell averaged CH4 mole fraction data is included for all measurement campaigns. The dataset also contains the calculations for CARB methodology comparisions and estimating statewide upscaling. Dairy facility information and coordinates have been removed from all files.
Dataset DOI: 10.5061/dryad.ht76hdrtc
Description of the data and file structure
These are data files associated with the manuscript Rodriguez et al., 2025 "Anaerobic digester installation significantly reduces liquid manure management CH4 emissions at a California dairy farm" published in GCB: Bioenergy.
All files have coordinates and dairy facility information removed to protect dairy identity and location.
Files and variables
File: CH4_Emissions_Results.csv
Description: "CH4 Emissions Results" contains the data output of CH4 emissions from the liquid manure storage complex as estimated by dispersion modeling for each measurement campaign. This data is used for Figure 2 in the manuscript and Figure S5 in the Supporting Information document.
Variables
- Campaign: Time of measurement pre or post digester installation.
- Month: Month of measurement
- Year: Year of measurement
- CH4: Methane emissions in units of kg CH4 per day
- Low.CH4: The low end value of the 95% confidence interval.
- High.CH4: The high end value of the 95% confidence interval.
- CH4.head: Methane emissions normalized by the total of number of animals on site. Units of kg CH4 per day per head.
- Low.CH4.head: The low end value of the 95% confidence interval normalized by the total number of animals on site.
- High.CH4.head: The high end value of the 95% confidence interval normalized by the total number of animals on site.
- CH4.lactatingcow: Methane emissions normalized by the just the number of lactating cows on site. Units of kg CH4 per day per lactating cow
- Low.CH4.lactatingcow: The low end value of the 95% confidence interval normalized by just the number of lactating cows on site.
- High.CH4.lactatingcow: The high end value of the 95% confidence interval normalized by just the number of lactating cows on site.
File: CH4_Emissions_Normalizations.xlsx
Description: "CH4 Emissions Normalizations" shows the calculations used to the normalize CH4 emissions from the liquid manure storage complex as estimated by dispersion modeling for each measurement campaign. The number of lactating cows is available for each campaign but the number for other animal classes is only available as an annual average. Cells with n/a value indicate that month is not applicable because these values use annual average.
Variables
- Campaign: Time of measurement pre or post digester installation.
- Month: Month of measurement
- Year: Year of measurement
- Animal Class: Diary animal classification categories existing on dairy site.
- AU: Animal unit.
- AU heads: Total number of animal based on AU conversion.
- CH4: Methane emissions in units of kg CH4 per day
- Low.CH4: The low end value of the 95% confidence interval.
- High.CH4: The high end value of the 95% confidence interval.
- CH4.head: Methane emissions normalized by the total of number of animals on site. Units of kg CH4 per day per head.
- Low.CH4.head: The low end value of the 95% confidence interval normalized by the total number of animals on site.
- High.CH4.head: The high end value of the 95% confidence interval normalized by the total number of animals on site.
- CH4.lactatingcow: Methane emissions normalized by the just the number of lactating cows on site. Units of kg CH4 per day per lactating cow
- Low.CH4.lactatingcow: The low end value of the 95% confidence interval normalized by just the number of lactating cows on site.
- High.CH4.lactatingcow: The high end value of the 95% confidence interval normalized by just the number of lactating cows on site.
- CH4.AU: Methane emissions normalized by animal unit.
- Low.CH4.AU: The low end value of the 95% confidence interval normalized animal unit
- High.CH4.AU: The high end value of the 95% confidence interval normalized by animal unit
File: CH4_Emissions_Relative_Change_and_Uncertainty_Calculation.xlsx
Description: "CH4 Emissions Relative Change and Uncertainty Calculation" shows the calculations for the percent relative change in methane emissions as a result of the digester installation by comparing paired measurement months. The uncertainty is calculated as the propagated error in the percent relative change calculation using the 95% confidence intervals. Calculation equations are given in the Supporting Information section 3.1. Cells with null value indicate cell is left intentionally blank as no data is necessary.
Variables
- Normalization: The type of mean CH4 emission normalization. Either none, normalized by total number of animal heads on site, normalized by total number of lactating cows on site, normalized by animal unit
- Campaign: Time of measurement pre or post digester installation.
- Month: Month of measurement
- Year: Year of measurement
- CH4: Mean measured CH4 emissions
- Low.CH4: The low end value of the 95% confidence interval.
- High.CH4: The high end value of the 95% confidence interval.
- Low.Difference: The absolute value difference between the mean and the low end of the 95% confidence interval used to calculate uncertainty.
- High.Difference: The absolute value difference between the mean and the high end of the 95% confidence interval used to calculate uncertainty.
- Unit: Units for numerical data in "CH4", "Low.CH4", "High.CH4", "Low.Difference", "High Difference".
- Years Compared: The year of the paired months compared for relative change calculation.
- Percent Relative Change: The percent (%) decrease in methane emissions after digester installation comparing paired months.
- Uncertainty: The percent (%) propagated error in the percent relative change calculation.
File: All_Receptor_Meteorology_and_CH4_Mole_Fraction_Data.csv
Description: "All Receptor Meteorology and CH4 Mole Fraction Data" is the averaged CH4 mole fraction and associated meteorology data for each receptor location at the liquid manure storage complex. This data serves as the input data used to estimate CH4 emissions via dispersion modeling. Coordinates are removed. Meteorology data was collected on site except for the June 2022 data is gathered from the Visalia Airport. Cells with n/a value indicate data was not measured or not recorded for that certain measurement campaign or time interval.
Variables
- Campaign: Time of measurement pre or post digester installation.
- Month: Month of measurement
- Year: Year of measurement
- TIMESTAMP: End timestamp for receptor measurement for which data is averaged over.
- CH4 ppm: Averaged methane mole fraction in ppm
- z2: The measurement height of the mobile laboratory in meters.
- Ubar: The mean wind speed in the horizontal direction in meters per second.
- Wbar: The mean wind speed in the vertical direction in meters per second.
- Tbar: The mean air temperature in degrees Celsius.
- sigmau: The standard deviation of wind speed in the u direction (east-west) in meters per second.
- sigmav: The standard deviation of wind speed in the v direction (north-south) in meters per second.
- sigmaw: The standard deviation of the vertical wind speed in meters per second.
- sigmaT: The standard deviation of the sonic measured air temperature in degrees Celsius.
- WindDirection: The mean wind direction in radians.
- WindDirectionDegrees: The mean wind direction in degrees.
- sigmaWD: The standard deviation of the wind direction in radians.
- HeatFlux: The heat energy transfer rate in Watts per square meter.
- ustar: The friction velocity (a metric of turbulence) in meters per second.
- MOLength: The Monin-Obukhov length, a unitless metric of atmospheric stability.
- Uscalar: The mean wind speed not accounting for wind direction in meters per second.
- n: The number of instantaneous measurements included in the time averaging.
- zref: The height of the stationary sonic anemometer in meters.
File: All_Instantaneous_Gridded_CH4_Mole_Fraction_Data.csv
Description: "All Instantaneous Gridded CH4 Mole Fraction Data" shows all the CH4 mole fraction data collected in the afternoon receptor measurements at the liquid manure storage complex. This data is used for visualizing CH4 mole fractions in Figure 3. This data is also used for visualizing CH4 mole fractions on a grid of the liquid manure storage complex by relating coordinates (removed in this dataset) to grid cells as identified in figure S6 in the Supporting Information document.
Variables
- Campaign: Time of measurement pre or post digester installation.
- Month: Month of measurement
- Year: Year of measurement
- TIMESTAMP: Timestamp of measurement in format of M/DD/YYYY h:mm:ss
- CH4 ppm: The instantaneous methane mole fraction.
- Grid Cell: The grid cell location as visualized in Figure S6 in the Supporting Information document.
File: CH4_Mole_Fraction_Grid_Cell_Summary.csv
Description: "CH4 Mole Fraction Grid Cell Summary" shows the summarized statistics data for each individual grid cell as visualized in Figure 4 in the manuscript and Figures S7 and S8 in the Supporting Information document. Cells with n/a values indicate data is not available because cannot be calculated with n = 1 measurements.
Variables
- Campaign: Time of measurement pre or post digester installation.
- Month: Month of measurement
- Grid Cell: The grid cell location as visualized in Figure S6 in the Supporting Information document.
- n: The number of instantaneous CH4 mole fraction measurements in a grid cell.
- mean CH4 ppm: The average of instantaneous CH4 mole fraction measurements in a grid cell.
- sd CH4 ppm: The standard deviation of instantaneous CH4 mole fraction measurements in a grid cell.
- se CH4 ppm: The standard error of instantaneous CH4 mole fraction measurements in a grid cell. Standard error is calculated as: se = (sd / n)
File: CARB_Estimates_Comparison.xlsx
Description: "CARB Estimates Comparison" shows the full calculation of annual average daily CH4 emission rate from the liquid manure storage complex as estimated using two methods informed by methodology used by the California Air Resources Board. These methodology and all variables are further described in the methods section of the manuscript and in the Supporting Information document section 2.4. This file also shows the comparison between estimated emissions and emissions measured on site in this study. Cells with n/a value indicate there is not measured uncertainty in bottom-up calculation methods used by California Air Resources Board.
File: Statewide_Upscaling_Dairy_Digesters.xlsx
Description: "Statewide Upscaling Dairy Digesters" shows the calculation for estimating the statewide impact of covered lagoon anaerobic digesters in California. This data considers CH4 emissions from liquid manure storage only. 139 dairies were identified to have installed or plan to install covered lagoon anaerobic digesters as described in section 2.5 in the manuscript. Dairy locations and information was removed. For each dairy, annual facility baseline anaerobic lagoon CH4 emissions was estimated for each facility using methodology from Marklein et al., 2021. The facility level decrease in CH4 emissions from liquid manure storage (anaerobic lagoons) was estimated using the average decrease in CH4 emissions after digester installation normalized by the number of lactating cows (82% +/- 16%) measured in this study. The Total annual CH4 decrease due to digester installation was estimated as the sum of facility level decreases. All values are in units of gigagrams (Gg).
Variables
- Annual Facility Baseline Lagoon CH4 Emissions: Baseline methane emissions from anaerobic lagoon manure storage for each dairy facility using methodology from Marklein et al., 2021. Units of gigagrams (Gg)
- Measured Annual Average CH4 Mitigation: The estimated decrease in anaerobic lagoon manure storage methane emissions (~82%) after covered lagoon anaerobic digester installation as measured in our study.
- Uncertainty in Measured CH4 Mitigation The estimated error in the Measured Annual Average CH4 Mitigation (~16%) as estimated in our study.
- Annual Facility CH4 Mitigation due to Digester: The estimated decrease in anaerobic lagoon manure storage methane emissions for each dairy facility after covered lagoon anaerobic digester installation considering out Measured Annual Average CH4 Mitigation (~82%). Units of Gg (gigagrams).
- Uncertainty in Estimated Mitigation: The estimated error in Annual Facility CH4 Mitigation due to Digester considering our Uncertainty in Measured CH4 Mitigation (~16%). Units of Gg (gigagrams).