151. Satellite sea surface temperature: a powerful tool for interpreting in situ pCO2 measurements in the equatorial Pacific Ocean
- Author
-
D. C. E. Bakker, J. Etcheto, Masao Ishii, Jacqueline Boutin, Richard A. Feely, Yves Dandonneau, Philip D. Nightingale, R. D. Ling, Nicolas Metzl, Hisayuki Y. Inoue, Rik Wanninkhof, Laboratoire d'océanographie dynamique et de climatologie (LODYC), Institut de Recherche pour le Développement (IRD)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), NOAA Pacific Marine Environmental Laboratory [Seattle] (PMEL), National Oceanic and Atmospheric Administration (NOAA), Meteorological Research Institute [Tsukuba] (MRI), Japan Meteorological Agency (JMA), Plymouth Marine Laboratory (PML), Plymouth Marine Laboratory, Laboratoire de Physique et Chimie Marines (LPCM), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), and NOAA Atlantic Oceanographic and Meteorological Laboratory (AOML)
- Subjects
Atmospheric Science ,010504 meteorology & atmospheric sciences ,010505 oceanography ,[SDE.MCG]Environmental Sciences/Global Changes ,Tropical instability waves ,Seasonality ,medicine.disease ,01 natural sciences ,Ocean dynamics ,Atmosphere ,Sea surface temperature ,Flux (metallurgy) ,13. Climate action ,Climatology ,medicine ,Upwelling ,Environmental science ,Spatial variability ,14. Life underwater ,ComputingMilieux_MISCELLANEOUS ,0105 earth and related environmental sciences - Abstract
In order to determine the seasonal and interannual variability of the CO 2 released to the atmosphere from the equatorial Pacific, we have developed p CO 2 -temperature relationships based upon shipboard oceanic CO 2 partial pressure measurements, p CO 2 , and satellite sea surface temperature, SST, measurements. We interpret the spatial variability in p CO 2 with the help of the SST imagery. In the eastern equatorial Pacific, at 5°S, p CO 2 variations of up to 100 μatm are caused by undulations in the southern boundary of the equatorial upwelled waters. These undulations appear to be periodic with a phase and a wavelength comparable to tropical instability waves, TIW, observed at the northern boundary of the equatorial upwelling. Once the p CO 2 signature of the TIW is removed from the Alize II cruise measurements in January 1991, the equatorial p CO 2 data exhibit a diel cycle of about 10 matm with maximum values occurring at night. In the western equatorial Pacific, the variability in p CO 2 is primarily governed by the displacement of the boundary between warm pool waters, where air–sea CO 2 fluxes are weak, and equatorial upwelled waters which release high CO 2 fluxes to the atmosphere. We detect this boundary using satellite SST maps. East of the warm pool, Δ P is related to SST and SST anomalies. The 1985–97 CO 2 flux is computed in a 5° wide latitudinal band as a combination of Δ P and CO 2 exchange coefficient, K , deduced from satellite wind speeds, U . It exhibits up to a factor 2 seasonal variation caused by K -seasonal variation and a large interannual variability, a factor 5 variation between 1987 and 1988. The interannual variability is primarily driven by displacements of the warm pool that makes the surface area of the outgassing region variable. The contribution of Δ P to the flux variability is about half the contribution of K . The mean CO 2 flux computed using either the Liss and Merlivat (1986) or the Wanninkhof (1992) K – U parametrization amounts to 0.11 GtC yr −1 or to 0.18 GtC yr −1 , respectively. The error in the integrated flux, without taking into account the uncertainty on the K – U parametrization, is less than 31%. DOI: 10.1034/j.1600-0889.1999.00025.x
- Published
- 1999
- Full Text
- View/download PDF