Identification

Title

Airborne observations of methane emissions from rice cultivation in the Sacramento Valley of California

Abstract

Airborne measurements of methane (CH₄) and carbon dioxide (CO₂) were taken over the rice growing region of California's Sacramento Valley in the late spring of 2010 and 2011. From these and ancillary measurements, we show that CH₄ mixing ratios were higher in the planetary boundary layer above the Sacramento Valley during the rice growing season than they were before it, which we attribute to emissions from rice paddies. We derive daytime emission fluxes of CH₄ between 0.6 and 2.0% of the CO₂ taken up by photosynthesis on a per carbon, or mole to mole, basis. We also use a mixing model to determine an average CH₄/CO₂ flux ratio of -0.6% for one day early in the growing season of 2010. We conclude the CH₄/CO₂ flux ratio estimates from a single rice field in a previous study are representative of rice fields in the Sacramento Valley. If generally true, the California Air Resources Board (CARB) greenhouse gas inventory emission rate of 2.7 × 1010 g CH₄/yr is approximately three times lower than the range of probable CH₄ emissions (7.8-9.3 × 1010 g CH₄/yr) from rice cultivation derived in this study. We attribute this difference to decreased burning of the residual rice crop since 1991, which leads to an increase in CH₄ emissions from rice paddies in succeeding years, but which is not accounted for in the CARB inventory.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d7736rq4

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

North bounding latitude

South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2012-12-01T00:00:00Z

Frequency of update

Quality and validity

Lineage

Conformity

Data format

name of format

version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact