Claim · model-written summary
The GT underestimation resulted from the lower GT inlet being in the roughness sublayer, where flux-gradient relationships are not valid.
- Taxon
- Black Spruce
Picea marianat0 - Outcome
- underestimatione0
- Qualifier
- lower GT inlet in the roughness sublayere0
Not reportedMaterialGeneCompoundOrgan / stageInteractorInteractor roleSecond interactorSecond interactor roleTreatmentComparatorSettingDirectionValue
Organisms pictured · Representative pictures of the matched species, not figures from the paper.
Verbatim
e0“The underestimation resulted from having the lower GT inlet in the roughness sublayer, in which the flux–gradient relationships are not valid”
t0“Black Spruce Stand”
Title
E. Pattey; R. L. Desjardins; H. Westberg; et al. Journal of Applied Meteorology 1999. doi:10.1175/1520-0450(1999)038<0870:moieoa>2.0.co;2
Other claims from this paper (11)
- Observation The average isoprene flux over the black spruce stand was 2.29 mg C m-2 h-1 in late July.
- Observation The average isoprene flux decreased to 0.54 mg C m-2 h-1 in early September.
- Mechanism Senescent needles and lower ambient air temperature were most likely the cause of the lower isoprene emissions measured in September.
- Association A relationship of isoprene flux with air temperature was derived at the canopy scale.
- Association High isoprene emissions were observed at temperatures above 25 degrees C.
- Mechanism The high isoprene emissions at temperatures above 25 degrees C were most likely related to thermoprotection of photosynthesis.
- Method / resource The diurnal trends of isoprene flux measured by gradient transport (GT) and relaxed eddy accumulation (REA) were similar.
- Method / resource Isoprene fluxes measured with GT were 63% lower than those measured with REA.
- Recommendation Measuring the gradient at about two canopy heights with spacing reduced from 10 to 3 m would reduce the underestimation of the scalar flux.
- Method / resource The reduced gradient spacing would also reduce the isoprene concentration differences by five to six times compared with those obtained with the REA technique.
- Recommendation Boreal zone black spruce should be assigned a standard emission rate of 6 rather than 18 ug C g-1 h-1.