What are some essential SoilC and GHG flux data sources that we should use?

[dlebauer]

Please list:

• variables measured including units
• temporal + spatial resolution
• temporal + spatial domain
• other relevant information and questions for discussion
• reference(s)
• links to data source(s)

[dlebauer]

Gridded National Inventory of U.S. Methane Emissions

Methane

• CH4 flux (Mg CH₄/km²/yr)
  • separated into 27 categories that include rice and field burning.
• Temporal Resolution and domain: Annual (2012-2020)
• Spatial Resolution and Domain: CONUS, 10 degree grid
• https://earth.gov/ghgcenter/data-catalog/epa-ch4emission-yeargrid-v2express
• Maasakkers et al 2016 Gridded National Inventory of U.S. Methane Emissions. EST. https://pubs.acs.org/doi/epdf/10.1021/acs.est.6b02878

Annual state-level emissions from rice cultivation are obtained from EPA and allocated to counties using acreage harvested from the USDA Census. (14) Emissions for each county are allocated to the 0.1° × 0.1° grid based on crop maps with 30 m resolution from the USDA Cropland Data Layer product. Annual emissions are then distributed over individual months using normalized mean 2001–2010 heterotrophic respiration rates from the 1° × 1° monthly Carbon Data-Model Framework (CARDAMOM) terrestrial C cycle analysis.
Emissions from field burning of agricultural residues of five individual crops (corn, rice, soybeans, sugar cane, and wheat) are allocated to a 2003–2007 monthly climatology of agricultural fires.

[dlebauer]

Here is an inventory of Ameriflux sites with GHG flux measurements: CH4 (26 sites) and N2O (14 sites)

• CH4 and N2O flux measurements
• site based, sub-daily
• this only covers US sites; varying temporal domain
• compiled from the search interface https://ameriflux.lbl.gov/sites/site-search/
  • NB: site names may have typos - I was just counting the sites while writing the proposal and noted these down, and transcribed them here so they don't get lost

Details

Site	CH4	N2O	Crop
US-Bi1	X	X	corn
US-Bi2	X	X	soy, winter wheat
US-CRT	X		annual and perennial croplands - alfalfa, soybean, wheat, cattle
US-HRA	X		rice
US-HRC	X		rice
US-TWC	X		alfalfa
US-Twt	X		rice
US-XSL	X		mixed
US-Ro6		X	sorn, soy, clover
US-RO5		X	corn, soy
US-RGW	X	X	rice
US-RGO	X	X	rice
US-RGF	X	X	corn, wheat with manure application
US-RGB	X	X	rice
US-RGA	X	X	bioenergy crops
US-DSB	X	X	rice
US-ARM	X	X	wheat, corn, soy, alfalfa
US-ER1	X	X	not stated - "ag land"
US-ER2		X	corn
US-BD4	X		rice
US-BD5	X		rice
US-BD6	X		rice
US-DS3	X	X	rice
US-BdC	X		rice, soy
US-BdA	X		rice, soy
US-OF1	X		rice, soy
US-OF2	X		rice, soy
US-RGG	X		rice
US-AWD	X		rice

Ameriflux_N2O_CH4_Sites.csv

[dlebauer]

CALGEM https://ww2.arb.ca.gov/ghg-inventory-data

• N2O, CH4 (along with other GHGs)
• Annual, state level, 2000-2021)
  • broken out by source (incl. mineral fertilizer, org fertilizer, manure, rice fields)

Can provide a good point of comparison of our state level estimates.

[dlebauer]

Satellite based measurements

Overview:
Jacob, Daniel J., et al. "Quantifying methane emissions from the global scale down to point sources using satellite observations of atmospheric methane." Atmospheric Chemistry and Physics 22.14 (2022): 9617-9646.

Of these, MethaneSat is the only one specifically identified as detecting agriculture.

Unclear whether this will be useful for ag applications. Data not yet available.

• CH4 flux
• resolution
  • spatial: 1km2 (500m possible?)
  • temporal freq: 7d
• domain:
  • temporal: 2024-
  • spatial: global
• detection threshold 100kg/h

Technical docs and comparison w/ other CH4 satellite products
MethaneSAT Technical considerations-May 2019.pdf

[dlebauer]

N2O flux data from Xia et al 2024 https://doi.org/10.1016/j.scitotenv.2024.171930

This is a summary of literature.

• key N2O variable is "Monthly N2O (units not given) measured including units
• dataset includes >50 additional covariates for each record
• temporal + spatial resolution: site specific
• temporal + spatial domain: N america

Dataset (excel spreadsheet) Soil N₂O Emissions in Organic Farming Systems: A North American Meta-Dataset https://doi.org/10.7916/q0np-1w51

[infotroph]

Meta-analysis of N2O emissions from specialty crops: Li et al 2024 https://onlinelibrary.wiley.com/doi/full/10.1111/gcb.17233