Observations of Rossby wave propagation in the Northeast Atlantic with TOPEX/POSEIDON altimetry

Cipollini, Paolo; Cromwell, D.; Quartly, G.

doi:10.1016/s0273-1177(99)00069-1

Cited by 28 publications

(29 citation statements)

References 7 publications

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“…The simulated Gulf Stream is less energetic than observed and slightly shifted to the north. The similarity of the wave amplitude and EKE fields has already been mentioned by Herrmann and Krauss (1989); Osychny and Cornillon (2004) in the Gulf Stream region and by Cipollini et al (1999);Cromwell (2001) at 33 • N and 34 • N. This suggests that most of the eddy activity diagnosed on EKE maps actually propagates to the west. Fig.…”

Section: Model/data Intercomparison At the Surfacesupporting

confidence: 71%

“…The 34-36 • N "waveguide" follows the trajectory of the Azores Current, which might contribute to the generation or amplification of the waves (e.g. Cipollini et al, 1999;Cromwell, 2006). As expected, the S sm maximum (C, grey lines) appears less contaminated by small-scale noise than the first S maximum (C m=1 , white dots), not only in the C p direction but also in the horizontal.…”

Section: Smoothing Algorithm -Extraction Of Phase Speedssupporting

confidence: 60%

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Depth dependence of westward-propagating North Atlantic features diagnosed from altimetry and a numerical 1/6° model

et al. 2008

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Abstract. A 1/6• numerical simulation is used to investigate the vertical structure of westward propagation between 1993 and 2000 in the North Atlantic ocean. The realism of the simulated westward propagating signals, interpreted principally as the signature of first-mode baroclinic Rossby waves (RW), is first assessed by comparing the simulated amplitude and zonal phase speeds of Sea Level Anomalies (SLA) against TOPEX/Poseidon-ERS satellite altimeter data. Then, the (unobserved) subsurface signature of RW phase speeds is investigated from model outputs by means of the Radon Transform which was specifically adapted to focus on firstmode baroclinic RW. The analysis is performed on observed and simulated SLA and along 9 simulated isopycnal displacements spanning the 0-3250 m depth range. Simulated RW phase speeds agree well with their observed counterparts at the surface, although with a slight slow bias. Below the surface, the simulated phase speeds exhibit a systematic deceleration with increasing depth, by a factor that appears to vary geographically. Thus, while the reduction factor is about 15-18% on average at 3250 m over the region considered, it appears to be much weaker (about 5-8%) in the eddy-active Azores Current, where westward propagating structures might be more coherent in the vertical. In the context of linear theories, these results question the often-made normal mode assumption of many WKB-based theories that the phase speed is independent of depth. Alternatively, these results could also suggest that the vertical structure of westward propagating signals may significantly depend on their degree of nonlinearity, with the degree of vertical coherence possibly increasing with the degree of nonlinearity.

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Section: Model/data Intercomparison At the Surfacesupporting

confidence: 71%

Section: Smoothing Algorithm -Extraction Of Phase Speedssupporting

confidence: 60%

Depth dependence of westward-propagating North Atlantic features diagnosed from altimetry and a numerical 1/6° model

et al. 2008

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“…The propagation speed in this band (and in other locations in the western part of the basin) is consistent with the speed expected for Rossby waves. This zonal waveguide of stronger Rossby wave propagation just south of the Azores Current had already been observed in T/P data by using standard Fourier and 2-d Radon transform methods (Cipollini et al 1997(Cipollini et al , 1999.…”

Section: Results For North Atlanticsupporting

confidence: 64%

Multi-sensor satellite monitoring of ocean climate

Guymer

Challenor

Cipollini

et al. 2002

Opertional Oceanography - Implementation at the European and Regional Scales, Proceedings of the Second International Conferenc

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In the 20 years since Seasat demonstrated that several ocean parameters could be measured to useful accuracy from a single platform satellite oceanography has advanced significantly. Not only has it been possible to measure new parameters but the ability to undertake global monitoring for a decade or so has given new insights to some phenomena which could not have been obtained from in situ data alone.The three examples discussed in this presentation, which have all been pioneered at SOC, have been chosen because of their relevance to climate change: variations in wave climate, the propagation of planetary waves across ocean basins and a new rainfall climatology. In addition to their use for monitoring changes in the coupled ocean-atmosphere system these datasets are invaluable for testing the models being developed for climate prediction.Wave height can be measured as accurately from satellite altimeters as from surface buoys and data accumulated since 1985 have been used to show both that the NE Atlantic became rougher and that fluctuations in different oceans may be linked. Planetary waves are an important mechanism for carrying information across ocean basins and may modify currents such as the Gulf Stream and Kuroshio. Detection of one type (Rossby waves) from satellite measurements of sea level, sea temperature and ocean colour will be presented; the inferred characteristics have already led to revisions of standard theories with implications for the way the oceans affect climate. Although unforeseen when the sensors were designed altimeters can also be used to identify rain events. A new precipitation climatology, derived from measured backscatter intensity, will be described and compared with previous work. It has the advantage of using a single sensor-type for tropical to polar latitudes.

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“…There have also been many papers written about the planetary wave signal observed in maps of SLA. The analysis presented in this section uses the radon technique that many of these papers have used to explore how planetary waves observed in the altimeter data fit the theoretical values (Chelton and Schlax, 1996;Killworth et al, 1997;Cipollini et al, 1999). The technique is used in this paper to also explore the similarities in the wave energy across a wide range of angles as well as westward planetary wave speeds.…”

Section: Wave Signalsmentioning

confidence: 99%

An ocean model's response to scatterometer winds

Tokmakian

2005

Ocean Modelling

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Two simulations of the North Atlantic have been run using the POP ocean model for approximately two and one half years each. One simulation used the 1.25°wind product from ECMWF and the other used the JPL Quikscat 0.25°gridded product. The resulting sea level anomaly fields from the simulations are quantified by using tide gauge and altimetric sea level anomaly data. In addition, upper ocean quantities were compared, such as the mix layer depths, to understand the difference in the ocean's response when using the different wind products. The analysis found that significant improvements were made in the representation at the surface, and in particular areas where comparison data exists such as the Labrador Sea. There was also improvement in the scatterometer forced run with more realistic depths of the mixed layer.

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Observations of Rossby wave propagation in the Northeast Atlantic with TOPEX/POSEIDON altimetry

Cited by 28 publications

References 7 publications

Depth dependence of westward-propagating North Atlantic features diagnosed from altimetry and a numerical 1/6° model

Depth dependence of westward-propagating North Atlantic features diagnosed from altimetry and a numerical 1/6° model

Multi-sensor satellite monitoring of ocean climate

An ocean model's response to scatterometer winds

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