DOI: 10.5061/dryad.ghx3ffc0g
title: ASRC Rooftop methane (CH<sub>4</sub>) observations and NYCMA observed and simulated ΔCH<sub>4</sub>, with coincident carbon monoxide (CO) observations and ΔCO

description: Methane (CH4) observations from the Advanced Science Research Center
 (ASRC) Rooftop Observatory in Hamilton Heights, West Harlem, Manhattan and
 calculated background methane and observed and simulated methane
 enhancements (ΔCH4) for the New York City metropolitan area (NYCMA)
 with coincident carbon monoxide (CO) observations and
 calculated background CO and observed and simulated ΔCO. All values
 reported hourly for January-May 2019-2024, when available. Observations
 and analyzed quantities are as described in "Missing wintertime
 methane emissions from New York City related to combustion" by Luke
 D. Schiferl, Andrew Hallward-Driemeier, Yuwei Zhao, Ricardo Toledo-Crow,
 and Róisín Commane.
description: # ASRC Rooftop methane (CH~4~) observations and NYCMA observed and
 simulated ΔCH~4~, with coincident carbon monoxide (CO) observations and
 ΔCO Methane (CH4) observations from the Advanced Science Research Center
 (ASRC) Rooftop Observatory in Hamilton Heights, West Harlem, Manhattan and
 calculated background methane and observed and simulated methane
 enhancements (ΔCH4) for the New York City metropolitan area (NYCMA) with
 coincident carbon monoxide (CO) observations and calculated background CO
 and observed and simulated ΔCO. All values reported hourly for January-May
 2019-2024, when available. Background methane and observed ΔCH4 calculated
 using the methane observations from Earth Networks site at Stockholm, New
 Jersey (SNJ) are also included for the same time period. For completeness,
 we also include CO observations from the Environmental Protection Agency
 (EPA) Air Quality System (AQS) at the Cornwall, Connecticut site. ##
 Description of the data and file structure The data is contained in a csv
 file called "ASRC_CH4_Observations.csv", where each row is an
 hour, each column is a variable as below: | Variable | Unit | Description
 | | :------------------------------ | :------------------ |
 :-------------------------------------------------------------------------------------- | | DATETIME\_START.UTC | YYYY-MM-DD HH:MM:SS | Hour start date and time in Coordinated Universal Time (UTC) | | DATETIME\_END.UTC | YYYY-MM-DD HH:MM:SS | Hour end date and time in Coordinated Universal Time (UTC) | | DATETIME\_START.EST | YYYY-MM-DD HH:MM:SS | Hour start date and time in Eastern Standard Time (EST) | | DATETIME\_END.EST | YYYY-MM-DD HH:MM:SS | Hour end date and time in Eastern Standard Time (EST) | | CH4\_obs.ASRC | ppb | CH4 observation at ASRC site | | city\_scale.ASRC | TRUE/FALSE | TRUE = city-scale, FALSE = local-scale for CH4\_obs.ASRC, CO\_obs.ASRC | | CH4\_bkgd.ASRC | ppb | Background CH4 as fifth percentile of rolling 10-day window of city-scale CH4\_obs.ASRC | | CH4\_bkgd.ASRC.minCI95 | ppb | Lower bound of 95% confidence interval (CI) for CH4\_bkgd.ASRC | | CH4\_bkgd.ASRC.maxCI95 | ppb | Upper bound of 95% CI for CH4\_bkgd.ASRC | | CH4\_bkgd.SNJ | ppb | Background CH4 as mean of rolling 10-day window of CH4 observation at the SNJ site | | CH4\_bkgd.SNJ.minCI95 | ppb | Lower bound of 95% CI for CH4\_bkgd.SNJ | | CH4\_bkgd.SNJ.maxCI95 | ppb | Upper bound of 95% CI for CH4\_bkgd.SNJ | | dCH4\_obs.ASRC\_ASRC | ppb | Observed ΔCH4 as CH4\_obs.ASRC – CH4\_bkgd.ASRC for city-scale observations | | dCH4\_obs.ASRC\_ASRC.minCI95 | ppb | Lower bound of 95% CI for dCH4\_obs.ASRC\_ASRC | | dCH4\_obs.ASRC\_ASRC.maxCI95 | ppb | Upper bound of 95% CI for dCH4\_obs.ASRC\_ASRC | | dCH4\_obs.ASRC\_SNJ | ppb | Observed ΔCH4 as CH4\_obs.ASRC – CH4\_bkgd.SNJ for city-scale observations | | dCH4\_obs.ASRC\_SNJ.minCI95 | ppb | Lower bound of 95% CI for dCH4\_obs.ASRC\_SNJ | | dCH4\_obs.ASRC\_SNJ.maxCI95 | ppb | Upper bound of 95% CI for dCH4\_obs.ASRC\_SNJ | | dCH4\_sim.EDGAR\_v60 | ppb | Simulated ΔCH4 as monthly EDGAR v6.0 CH4 emissions × surface influence footprint | | dCH4\_sim.EDGAR\_v80 | ppb | Simulated ΔCH4 as monthly EDGAR v8.0 CH4 emissions × surface influence footprint | | dCH4\_sim.EPA\_GHGI\_v2016 | ppb | Simulated ΔCH4 as monthly EPA GHGI v2016 CH4 emissions × surface influence footprint | | dCH4\_sim.EPA\_GHGI\_v2023 | ppb | Simulated ΔCH4 as monthly EPA GHGI v2023 CH4 emissions × surface influence footprint | | dCH4\_sim.EPA\_GHGI\_v2023\_EE | ppb | Simulated ΔCH4 as monthly EPA GHGI v2023 EE CH4 emissions × surface influence footprint | | dCH4\_sim.Pitt\_A1\_VS1\_SN | ppb | Simulated ΔCH4 as Pitt High-Res A1\_VS1\_SN CH4 emissions × surface influence footprint | | dCH4\_sim.Pitt\_A1\_AS1\_SN | ppb | Simulated ΔCH4 as Pitt High-Res A1\_AS1\_SN CH4 emissions × surface influence footprint | | dCH4\_sim.Pitt\_A1\_VS1\_SS | ppb | Simulated ΔCH4 as Pitt High-Res A1\_VS1\_SS CH4 emissions × surface influence footprint | | dCH4\_sim.Pitt\_A1\_AS1\_SS | ppb | Simulated ΔCH4 as Pitt High-Res A1\_AS1\_SS CH4 emissions × surface influence footprint | | dCH4\_sim.Pitt\_AL\_AS1\_SS | ppb | Simulated ΔCH4 as Pitt High-Res AL\_AS1\_SS CH4 emissions × surface influence footprint | | dCH4\_sim.Pitt\_AL\_VS1\_SS | ppb | Simulated ΔCH4 as Pitt High-Res AL\_VS1\_SS CH4 emissions × surface influence footprint | | dCH4\_sim.Pitt\_AL\_AS1\_SN | ppb | Simulated ΔCH4 as Pitt High-Res AL\_AS1\_SN CH4 emissions × surface influence footprint | | dCH4\_sim.Pitt\_AL\_VS1\_SN | ppb | Simulated ΔCH4 as Pitt High-Res AL\_VS1\_SN CH4 emissions × surface influence footprint | | dCH4\_sim.Pitt\_V5\_VS1\_SS | ppb | Simulated ΔCH4 as Pitt High-Res V5\_VS1\_SS CH4 emissions × surface influence footprint | | dCH4\_sim.Pitt\_V5\_AS1\_SS | ppb | Simulated ΔCH4 as Pitt High-Res V5\_AS1\_SS CH4 emissions × surface influence footprint | | dCH4\_sim.Pitt\_V5\_VS1\_SN | ppb | Simulated ΔCH4 as Pitt High-Res V5\_VS1\_SN CH4 emissions × surface influence footprint | | dCH4\_sim.Pitt\_V5\_AS1\_SN | ppb | Simulated ΔCH4 as Pitt High-Res V5\_AS1\_SN CH4 emissions × surface influence footprint | | dCH4\_sim.Pitt\_VL\_VS1\_SS | ppb | Simulated ΔCH4 as Pitt High-Res VL\_VS1\_SS CH4 emissions × surface influence footprint | | dCH4\_sim.Pitt\_VL\_AS1\_SS | ppb | Simulated ΔCH4 as Pitt High-Res VL\_AS1\_SS CH4 emissions × surface influence footprint | | dCH4\_sim.Pitt\_VL\_VS1\_SN | ppb | Simulated ΔCH4 as Pitt High-Res VL\_VS1\_SN CH4 emissions × surface influence footprint | | dCH4\_sim.Pitt\_VL\_AS1\_SN | ppb | Simulated ΔCH4 as Pitt High-Res VL\_AS1\_SN CH4 emissions × surface influence footprint | | CO\_obs.ASRC | ppb | CO observation at ASRC site | | CO\_obs.Cornwall | ppb | CO observation at Cornwall site | | CO\_bkgd.ASRC | ppb | Background CO as fifth percentile of rolling 10-day window of city-scale CO\_obs.ASRC | | CO\_bkgd.ASRC.minCI95 | ppb | Lower bound of 95% CI for CO\_bkgd.ASRC | | CO\_bkgd.ASRC.maxCI95 | ppb | Upper bound of 95% CI for CO\_bkgd.ASRC | | CO\_bkgd.Cornwall | ppb | Background CO as mean of rolling 10-day window of CO observation at the Cornwall site | | CO\_bkgd.Cornwall.minCI95 | ppb | Lower bound of 95% CI for CO\_bkgd.Cornwall | | CO\_bkgd.Cornwall.maxCI95 | ppb | Upper bound of 95% CI for CO\_bkgd.Cornwall | | dCO\_obs.ASRC\_ASRC | ppb | Observed ΔCO as CO\_obs.ASRC – CO\_bkgd.ASRC for city-scale observations | | dCO\_obs.ASRC\_ASRC.minCI95 | ppb | Lower bound of 95% CI for dCO\_obs.ASRC\_ASRC | | dCO\_obs.ASRC\_ASRC.maxCI95 | ppb | Upper bound of 95% CI for dCO\_obs.ASRC\_ASRC | | dCO\_obs.ASRC\_Cornwall | ppb | Observed ΔCO as CO\_obs.ASRC – CH4\_bkgd.Cornwall for city-scale observations | | dCO\_obs.ASRC\_Cornwall.minCI95 | ppb | Lower bound of 95% CI for dCO\_obs.ASRC\_Cornwall | | dCO\_obs.ASRC\_Cornwall.maxCI95 | ppb | Upper bound of 95% CI for dCO\_obs.ASRC\_Cornwall | | dCO\_sim.EDGAR\_v81 | ppb | Simulated ΔCO as monthly EDGAR v8.1 CO emissions × surface influence footprint | CH4_obs.ASRC and CO_obs.ASRC were measured by several instruments throughout the collection period: (i) Picarro G2401-m for 2019, 2020, and 1 January–16 March 2023 (reporting at 0.5–1 Hz), (ii) Picarro G2401 for 2021, 16 March–31 May 2023, and 2024 (reporting at ~0.3 Hz), and (iii) Aerodyne SuperDUAL for 2022 (reporting at 1 Hz). Each instrument was calibrated using gas cylinders that are traceable to standards calibrated by the Central Calibration Laboratory (CCL) at the National Oceanographic and Atmospheric Administration (NOAA) Global Monitoring Laboratory (GML) in Boulder, CO. CCL maintains the World Meteorological Organization (WMO) methane (WMO X2004A) and CO scales (WMO X2014A). The Aerodyne SuperDUAL set-up at ASRC is described by Commane et al. (2023).  Simulated ΔCH4 from each of 16 ensemble versions of the the Pitt High-Resolution Inventory (dCH4_sim.Pitt_*aabbbcc*) are calculated using varying scaling assumptions for the wastewater, stationary combustion, and natural gas distribution and post-meter sectors. Each Pitt version follows the coding pattern of *aa*: A1 (ACES 1-state), AL (ACES Local), V5 (Vulcan 5-state), VL (Vulcan Local); *bbb*: AS1 (ACES 1-state), VS1 (Vulcan 1-state); *cc*: SN (Sewer National), SS (Sewer State). Missing data is reported as NA. CH4_obs.ASRC and CO_obs.ASRC are pre-filtered keeping only hours with at least 50% valid sub-hourly measurements (e.g., at least 1800 1-Hz measurements). Additional observations and analyzed quantities are as described in "Missing wintertime methane emissions from New York City related to combustion" by Luke D. Schiferl, Andrew Hallward-Driemeier, Yuwei Zhao, Ricardo Toledo-Crow, and Róisín Commane. This archive extends the record of CO and ΔCO at the ASRC Rooftop for 2019-2022 available at [https://doi.org/10.5061/dryad.612jm649n](https://doi.org/10.5061/dryad.612jm649n). ## Access information Methane observations from the SNJ site are available from [https://data.nist.gov/od/id/mds2-3765](https://data.nist.gov/od/id/mds2-3765). The Emissions Database for Global Atmospheric Research (EDGAR) v6.0 CH4 emissions used to create simulated ΔCH4 (dCH4_sim.EDGAR_v60) are available from [https://edgar.jrc.ec.europa.eu/dataset_ghg60](https://edgar.jrc.ec.europa.eu/dataset_ghg60). The EDGAR v8.0 CH4 emissions used to create simulated ΔCH4 (dCH4_sim.EDGAR_v80) are available from [https://edgar.jrc.ec.europa.eu/dataset_ghg80](https://edgar.jrc.ec.europa.eu/dataset_ghg80). The EPA Greenhouse Gas Inventory (GHGI) v2016 CH4 emissions used to create simulated ΔCH4 (dCH4_sim.EPA_GHGI_v2016) are available from  [https://www.epa.gov/ghgemissions/gridded-2012-methane-emissions](https://www.epa.gov/ghgemissions/gridded-2012-methane-emissions). The EPA GHGI v2023 and EPA GHGI v2023 with Express Extension (EE) CH4 emissions used to create simulated ΔCH4 (dCH4_sim.EPA_GHGI_v2023, dCH4_sim.EPA_GHGI_v2023) are available from [https://zenodo.org/records/8367082](https://zenodo.org/records/8367082). The Pitt High-Resolution Inventory CH4 emissions used to create simulated ΔCH4 (dCH4_sim.Pitt_*aabbbcc*) are available from [https://data.nist.gov/od/id/mds2-2915](https://data.nist.gov/od/id/mds2-2915). The Cornwall CO observations (CO_obs.Cornwall) are also available from [https://aqs.epa.gov/aqsweb/airdata/download_files.html](https://aqs.epa.gov/aqsweb/airdata/download_files.html). The EDGAR v8.1 CO emissions used to create simulated ΔCO (dCO_sim.EDGAR_v81) are available from [https://edgar.jrc.ec.europa.eu/index.php/dataset_ap81](https://edgar.jrc.ec.europa.eu/index.php/dataset_ap81). The STILT model and HRRR ARL files used to create the HRRR-STILT surface influence footprints are available from [https://uataq.github.io/stilt/#/](https://uataq.github.io/stilt/#/) and [https://www.ready.noaa.gov/archives.php](https://www.ready.noaa.gov/archives.php). ### Version changes Oct 07, 2025: This update now includes the methane background and ΔCH4 calculated using observations from the SNJ site (CH4_bkgd.SNJ, dCH4_obs.ASRC_SNJ) for 2023-2024, values which were previously not available to be published in the public domain. The README is also updated to provide access information for the complete set of SNJ observations and to fix a typo in the description column for variable CO_obs.ASRC.