An altimetry‐based gravest empirical mode south of Africa: 1. Development and validation

Swart, Sebastiaan; Speich, Sabrina; Ansorge, Isabelle; Lütjeharms, J. R. E.

doi:10.1029/2009jc005299

Cited by 69 publications

(103 citation statements)

References 41 publications

(98 reference statements)

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“…The mixedlayer depth was calculated following de Boyer Montégut et al (2004), where the temperature differs from the temperature at 10 m by more than 0.2 • C ( T 10 m = 0.2 • C). The position of the fronts were determined using sea surface height (SSH) data from maps of absolute dynamic topography (MADT) (Swart et al, 2010). The percentage euphotic depth was calculated as a function of the natural log of in situ PAR and the diffuse attenuation coefficient K z .…”

Section: Ancillary Datamentioning

confidence: 99%

Seasonal development of iron limitation in the sub-Antarctic zone

Ryan‐Keogh

Thomalla

Mtshali³

et al. 2018

Biogeosciences

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Abstract. The seasonal and sub-seasonal dynamics of iron availability within the sub-Antarctic zone (SAZ; ∼ 40-45 • S) play an important role in the distribution, biomass and productivity of the phytoplankton community. The variability in iron availability is due to an interplay between winter entrainment, diapycnal diffusion, storm-driven entrainment, atmospheric deposition, iron scavenging and iron recycling processes. Biological observations utilizing grow-out iron addition incubation experiments were performed at different stages of the seasonal cycle within the SAZ to determine whether iron availability at the time of sampling was sufficient to meet biological demands at different times of the growing season. Here we demonstrate that at the beginning of the growing season, there is sufficient iron to meet the demands of the phytoplankton community, but that as the growing season develops the mean iron concentrations in the mixed layer decrease and are insufficient to meet biological demand. Phytoplankton increase their photosynthetic efficiency and net growth rates following iron addition from midsummer to late summer, with no differences determined during early summer, suggestive of seasonal iron depletion and an insufficient resupply of iron to meet biological demand. The result of this is residual macronutrients at the end of the growing season and the prevalence of the high-nutrient low-chlorophyll (HNLC) condition. We conclude that despite the prolonged growing season characteristic of the SAZ, which can extend into late summer/early autumn, results nonetheless suggest that iron supply mechanisms are insufficient to maintain potential maximal growth and productivity throughout the season.

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Section: Ancillary Datamentioning

confidence: 99%

Seasonal development of iron limitation in the sub-Antarctic zone

Ryan‐Keogh

Thomalla

Mtshali³

et al. 2018

Biogeosciences

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“…The vertical distributions of temperature and salinity are represented as functions of SSDH, as performed in the Antarctic Circumpolar Current region by Sun and Watts (2001) and Swart et al (2010), in the North Pacific western subarctic gyre region by Nagano et al (2016), and in other regions. Through the linear relationship between SSDH and SSH, the vertical hydrographic distributions can be inferred by altimetric SSH.…”

Section: Introductionmentioning

confidence: 99%

Heat transport variation due to change of North Pacific subtropical gyre interior flow during 1993–2012

et al. 2016

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Applying segment-wise altimetry-based gravest empirical mode method to expendable bathythermograph temperature, Argo salinity, and altimetric sea surface height data in March, June, and November from San Francisco to near Japan (30 • N, 145 • E) via Honolulu, we estimated the component of the heat transport variation caused by change in the southward interior geostrophic flow of the North Pacific subtropical gyre in the top 700 m layer during 1993-2012. The volume transport-weighted temperature (T I ) is strongly dependent on the season. The anomaly of T I from the mean seasonal variation, whose standard deviation is 0.14 • C, was revealed to be caused mainly by change in the volume transport in a potential density layer of 25.0 − 25.5σ θ . The anomaly of T I was observed to vary on a decadal or shorter, i.e., quasi-decadal (QD), timescale. The QD-scale variation of T I had peaks in 1998 and 2007, equivalent to the reduction in the net heat transport by 6 and 10 TW, respectively, approximately 1 year before those of sea surface temperature (SST) in the warm pool region, east of the Philippines. This suggests that variation in T I affects the warm pool SST through modification of the heat balance owing to the entrainment of southward transported water into the mixed layer.

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“…These available and valuable satellites' altimetry data include the Topex/Poseidon, Jason products, ERS-1/2, Envisat altimeters, and all gridded sea level products from AVISO (e.g., [27,31,41,56,59,85], etc.) with extremely good coverage in space and time [56].…”

Section: Sea Surface Heightmentioning

confidence: 99%

A Review of Ocean/Sea Subsurface Water Temperature Studies from Remote Sensing and Non-Remote Sensing Methods

Akbari

Alavipanah

Jeihouni

et al. 2017

Water

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Oceans/Seas are important components of Earth that are affected by global warming and climate change. Recent studies have indicated that the deeper oceans are responsible for climate variability by changing the Earth's ecosystem; therefore, assessing them has become more important. Remote sensing can provide sea surface data at high spatial/temporal resolution and with large spatial coverage, which allows for remarkable discoveries in the ocean sciences. The deep layers of the ocean/sea, however, cannot be directly detected by satellite remote sensors. Therefore, researchers have examined the relationships between salinity, height, and temperature of the oceans/Seas to estimate their subsurface water temperature using dynamical models and model-based data assimilation (numerical based and statistical) approaches, which simulate these parameters by employing remotely sensed data and in situ measurements. Due to the requirements of comprehensive perception and the importance of global warming in decision making and scientific studies, this review provides comprehensive information on the methods that are used to estimate ocean/sea subsurface water temperature from remotely and non-remotely sensed data. To clarify the subsurface processes, the challenges, limitations, and perspectives of the existing methods are also investigated.

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An altimetry‐based gravest empirical mode south of Africa: 1. Development and validation

Cited by 69 publications

References 41 publications

Seasonal development of iron limitation in the sub-Antarctic zone

Seasonal development of iron limitation in the sub-Antarctic zone

Heat transport variation due to change of North Pacific subtropical gyre interior flow during 1993–2012

A Review of Ocean/Sea Subsurface Water Temperature Studies from Remote Sensing and Non-Remote Sensing Methods

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