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Abstract The air‐sea exchange of oxygen (O2) is driven by changes in solubility, biological activity, and circulation. The total air‐sea exchange of O2has been shown to be closely related to the air‐sea exchange of heat on seasonal timescales, with the ratio of the seasonal flux of O2to heat varying with latitude, being higher in the extratropics and lower in the subtropics. This O2/heat ratio is both a fundamental biogeochemical property of air‐sea exchange and a convenient metric for testing earth system models. Current estimates of the O2/heat flux ratio rely on sparse observations of dissolved O2, leaving it fairly unconstrained. From a model ensemble we show that the ratio of the seasonal amplitude of two atmospheric tracers, atmospheric potential oxygen (APO) and the argon‐to‐nitrogen ratio (Ar/O2), exhibits a close relationship to the O2/heat ratio of the extratropics (40–). The amplitude ratio,/, is relatively constant within the extratropics of each hemisphere due to the zonal mixing of the atmosphere./is not sensitive to atmospheric transport, as most of the observed spatial variability in the seasonal amplitude ofAPO is compensated by similar variations in(Ar/). From the relationship between/heat and/in the model ensemble, we determine that the atmospheric observations suggest hemispherically distinct/heat flux ratios of 3.30.3 and 4.70.8 nmolbetween 40 andin the Northern and Southern Hemispheres respectively, providing a useful constraint forand heat air‐sea fluxes in earth system models and observation‐based data products.
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Duality Constraints on Counterterms in Supergravities
Abstract The UV finiteness found in calculations of the 4‐point amplitude insupergravity at loop orderhas not been explained, which motivates our study of the relevant superspace invariants and on‐shell superamplitudes for bothand. The local 4‐point superinvariants forare expected to have nonlinear completions whose 6‐point amplitudes have non‐vanishing SSL's (soft scalar limits), violating the behavior required of Goldstone bosons. For, we find atthat local 6‐point superinvariant and superamplitudes, which might cancel these SSL's, do not exist. This rules out the candidate 4‐point counterterm and thus gives a plausible explanation of the observedfiniteness. However, atwe construct a local 6‐point superinvariant with non‐vanishing SSL's, so the SSL argument does not explain the observedUV finiteness. Forsupergravity there are no 6‐point invariants at eitheror 4, so the SSL argument predicts UV finiteness.
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- Award ID(s):
- 1720397
- PAR ID:
- 10074771
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Fortschritte der Physik
- Volume:
- 66
- Issue:
- 10
- ISSN:
- 0015-8208
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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