Seasonal landfill methane emissions driven by temperature and pressure
Data files
Jan 04, 2026 version files 562.52 MB
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monthly_results.csv
2.19 KB
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pressure_dependence_results.csv
676 B
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README.md
6.69 KB
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temperature_dependence_results.csv
689 B
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tower_observations_30s.csv
562.51 MB
Abstract
More than a quarter of anthropogenic global warming has been attributed to methane growth in the atmosphere. Landfills account for 17 % of estimated methane emissions in the United States of America (USA), according to the Environmental Protection Agency (EPA), but studies show that many landfills emit more than reported. We developed a novel method to calculate monthly methane emissions from an active landfill using atmospheric methane mixing ratios observed from a single tower in New Jersey, USA. The tower method provides two and a half years of semi-continuous measurements and therefore observes more of the variability of methane emissions and lacks the sampling bias present in other methods. Time-specific comparison of tower-based methane emissions against those observed from summertime aircraft sampling and year-round mobile ground-based platforms showed good agreement. Estimated methane emissions for 2023 were five times greater than those reported to the EPA. We observed a strong seasonality in methane emissions, with a peak in the winter and a minimum in the summer. This seasonal cycle was driven by a strong negative dependence on air temperature and the change in atmospheric pressure. Our results highlight the importance of observations in non-ideal weather conditions (such as declining pressure and near-freezing temperatures) when methane emissions are largest. We suggest that this methodology could be applied to other suitable landfills to improve estimates of methane emissions.
Dataset DOI: 10.5061/dryad.ghx3ffc34
Description of the data and file structure
The file tower_observations_30s contains the 30-second merged dataset for all observations at the PAMS tower site (40.46228, -74.42932) taken at 20 m height above ground level. Gas concentration data were calibrated and merged to 30-seconds using the calibration method described in the associated manuscript. Wind data have a native 30-second resolution, while insolation has a native 1-minute resolution. PBL height comes from NOAA’s hourly High Resolution Rapid Refresh model, and atmospheric pressure and temperature are measured every 5 minutes. Those values have been linearly interpolated to the 30-second resolution of the wind measurements. Data from the New Jersey Mesonet site in East Brunswick, NJ (40.473318, -74.393765) are also provided. These have a native 5-minute resolution and columns have the prefix “EB” attached to indicate the East Brunswick site. Column names contain units at the end (e.g., CH4.g.m3 is methane measured in grams per cubic meter).
The file pressure_dependence_results.csv contains the tower, aircraft, and mobile-based estimates for methane emissions (in kg/hour) along with corresponding 6-hour pressure change (for the tower). Similarly, the file temperature_dependence_results.csv contains the same but with the corresponding temperatures.
The file monthly_results.csv has estimated emissions in kg/hour for each month using the tower data.
Files and variables
File: tower_observations_30s.csv
Description:
Variables
- utctime: Time in UTC
- CH4.ppbv: Calibrated methane measurement from the Picarro G2401, in parts per billion by volume
- CO.ppbv: Calibrated carbon monoxide measurement from the Picarro G2401, in parts per billion by volume
- CO2.ppmv: Calibrated carbon dioxide measurement from the Picarro G2401, in parts per million by volume
- H2O.ppthv: Calibrated humidity measurement from the Picarro G2401, in parts per thousand by volume
- C2H6.ppbv: Calibrated ethane measurement from the Aeris MIRA Ultra, in parts per billion by volume
- N2O.ppbv: Calibrated nitrous oxide measurement from the Aeris MIRA Ultra, in parts per billion by volume
- wind.speed.m/s: Wind speed from the EPA PAMS site at 20 meters height, in meters per second
- wind.direction.degrees: Wind direction from the EPA PAMS site at 20 meters height, in degrees
- temp.C: Temperature measured at the EPA PAMS site at 20 meters height, in Celsius
- pressure.hPa: Barometric pressure measured at the EPA PAMS site at 2 meters height, in hectopascals
- insolation.W.m2: Shortwave insolation measured at the EPA PAMS site, in Watts per square meter
- PBL.m: Planetary Boundary Layer height from the NOAA High Resolution Rapid Refresh model, taken from the grid box nearest the PAMS site
- CH4.g.m3: Calibrated methane measurement from the Picarro G2401, in grams per cubic meter
- CH4.enhancement.g.m3: Methane enhancement above background, in grams per cubic meter
- mean.wind.direction.degrees: Mean wind direction over the preceding amount of time corresponding to the transit time between the landfill and the PAMS site, from the 20-meter PAMS site measurement, in degrees
- mean.wind.speed.m/s: Mean wind speed over the preceding amount of time corresponding to the transit time between the landfill and the PAMS site, from the 20-meter PAMS site measurement, in meters per second
- mean.insolation.W.m2: Mean insolation over the preceding amount of time corresponding to the transit time between the landfill and the PAMS site, from the PAMS site measurement, in Watts per square meter
- EB.wind.direction.degrees: Wind direction from the New Jersey Mesonet site in East Brunswick located next to the landfill, in degrees
- EB.wind.speed.m/s: Wind speed from the New Jersey Mesonet site in East Brunswick located next to the landfill, in meters per second
- EB.pressure.hPa: Barometric pressure from the New Jersey Mesonet site in East Brunswick located next to the landfill, in hectopascals
- EB.temp.C: Temperature from the New Jersey Mesonet site in East Brunswick located next to the landfill, in Celsius
File: temperature_dependence_results.csv
Description:
Variables
- temperature.C: Center of the corresponding temperature range (for the tower data, using the measurement at the New Jersey Mesonet site) or instantaneous temperature (for the aircraft and mobile data), in Celsius
- mean.flux.estimate: Mean estimate of the flux for that temperature or temperature range, in kg/hour
- median.flux.estimate: Median estimate of the flux for that temperature or temperature range, in kg/hour
- higher.bound.estimate: Upper bound estimate of the flux for that temperature or temperature range, in kg/hour
- lower.bound.estimate: Lower bound estimate of the flux for that temperature or temperature range, in kg/hour
- type: Categorical variable describing the type of flux estimate: tower-based, aircraft, or mobile drive
File: pressure_dependence_results.csv
Description:
Variables
- pressure.change.hPa/hour: Center of the corresponding 6-hour pressure change range (for the tower data, using the measurement at the New Jersey Mesonet site) or pressure change over the preceding 6-hours (for the aircraft and mobile data), in hectopascals per hour
- mean.flux.estimate: Mean estimate of the flux for that pressure or pressure range, in kg/hour
- median.flux.estimate: Median estimate of the flux for that pressure or pressure range, in kg/hour
- higher.bound.estimate: Upper bound estimate of the flux for that pressure or pressure range, in kg/hour
- lower.bound.estimate: Lower bound estimate of the flux for that pressure or pressure range, in kg/hour
- type: Categorical variable describing the type of flux estimate: tower-based, aircraft, or mobile drive
File: monthly_results.csv
Description:
Variables
- year: Year the measurements occurred
- month: Month the measurements occurred
- day: Day the measurements occurred. Since tower measurements include data for the entire month, the day is left NA
- mean.estimate: Mean estimate of the flux, in kg/hour
- lower.bound.estimate: Lower bound estimate of the flux, in kg/hour
- upper.bound.estimate: Upper bound estimate of the flux, in kg/hour
- type: Categorical variable describing the type of flux estimate: tower-based, aircraft, or mobile drive
Code/software
All files are .csv format and can be opened with any spreadsheet software or coding language.