Satellite measurements of sea-surface temperature (SST) by the TRMM Microwave Imager reveal previously unreported features of tropical instability waves (TIWs). In the Pacific, TIW-related variability is observed from the eastern boundary to at least 160°E. Cusp-shaped distortions of SST fronts and associated trains of anticyclonic vortices both north and south...
Three mechanisms for self-induced Ekman pumping in the interiors of mesoscale ocean eddies are investigated.
The first arises from the surface stress that occurs because of differences between surface wind and
ocean velocities, resulting in Ekman upwelling and downwelling in the cores of anticyclones and cyclones,
respectively. The second mechanism...
Measurements of near-surface winds by the NASA scatterometer (NSCAT) from October 1996 through June 1997 are analyzed to investigate the three major wind jets along the Pacific coast of Central America that blow over the Gulfs of Tehuantepec, Papagayo, and Panama. Each jet is easily identifiable as locally intense offshore...
Satellite estimates of winds at 10 m above the sea surface by the NASA scatterometer (NSCAT) during the 9-month period October 1996–June 1997 are analyzed to investigate the correlations between the three major wind jets along the Pacific coast of Central America and their relationships to the wind and pressure...
The objective of this article is to present evidence for
the existence of seasonal variability in sea surface height
(SSH) anomaly in the Agulhas Retroflection region.
TOPEX/POSEIDON altimeter data are used to estimate
seasonal changes in the mesoscale SSH variability.
There is a seasonal oscillation of SSH variability characterized
by...
The circulation of the southwestern Atlantic Ocean is dominated by the Subtropical Gyre
and the confluence of the Brazil and Malvinas currents. Observations indicate that the latitude
of this confluence changes seasonally, lying farther north during the austral winter than during
the summer. This phenomenon has important consequences for the...
Seasonal variability of alongshore geostrophic velocity relative to 500 dbar is examined from 23 years
of hydrographic data along two sections off central California (one off Point Sur and the other off Point
Conception). The seasonal cycles are determined by least square fits of the gappy data records to
harmonics...
A mean reference surface and time-dependent orbit errors are estimated simultaneously for
each exact-repeat ground track from the first two years of Geosat sea level estimates based on
the Goddard Earth model (GEM)-T2 orbits. Motivated by orbit theory and empirical analysis of
Geosat data, the time-dependent orbit errors are modeled...
Observations, primarily from satellites, have shown a statistical relationship between the surface wind stress and underlying sea surface temperature (SST) on intermediate space and time scales, in many regions inclusive of eastern boundary upwelling current systems. In this paper, this empirical SST–wind stress relationship is utilized to provide a simple...
Boreal summer intraseasonal (30–90-day time scale) sea surface temperature (SST) variability in the east Pacific warm pool is examined using Tropical Rainfall Measuring Mission (TRMM) Microwave Imager (TMI) sea surface temperatures during 1998–2005. Intraseasonal SST variance maximizes at two locations in the warm pool: in the vicinity of 9°N, 92°W...
Satellite observations of wind stress and sea surface temperature (SST) are analyzed to investigate ocean–atmosphere interaction in the California Current System (CCS). As in regions of strong SST fronts elsewhere in the World Ocean, SST in the CCS region is positively correlated with surface wind stress when SST fronts are...
Mean-squared errors of surface geostrophic velocity estimates from the crossover and parallel-track methods are calculated for altimeters in the Ocean Topography Experiment (TOPEX)/Poseidon and Jason orbits. As part of the crossover method analysis, the filtering properties and errors of cross-track speed estimates are examined. Velocity estimates from both the crossover...
A technique previously developed for assessing the effects of sampling errors on sea surface height (SSH) fields constructed from satellite altimeter data is extended to include measurement errors, thus providing estimates of the total mean-squared error of the SSH fields. The measurement error contribution becomes an important consideration with the...
The effects of surface wind speed and direction gradients on midlatitude surface vorticity and divergence fields associated with mesoscale sea surface temperature (SST) variability having spatial scales of 100–1000 km are investigated using vector wind observations from the SeaWinds scatterometer on the Quick Scatterometer (QuikSCAT) satellite and SST from the...
The latitudinal structure of annual equatorial Rossby waves in the tropical Pacific Ocean based on sea surface height (SSH) and thermocline depth observations is equatorially asymmetric, which differs from the structure of the linear waves of classical theory that are often presumed to dominate the variability. The nature of this...
The long-term evolution of initially Gaussian eddies is studied in a reduced-gravity shallow-water model using both linear and nonlinear quasigeostrophic theory in an attempt to understand westward-propagating mesoscale eddies observed and tracked by satellite altimetry. By examining both isolated eddies and a large basin seeded with eddies with statistical characteristics...
The impact of SST specification on low-level winds in the operational ECMWF numerical weather prediction model is investigated in the eastern tropical Pacific from comparisons of ECMWF wind stress fields with QuikSCAT satellite scatterometer observations of wind stress during the August–December cold seasons of 2000 and 2001. These two time...
Westward propagating Gaussian eddies with statistical characteristics estimated from altimeter observations but with purely random starting locations and times produce striated features in time-averaged maps of zonal velocity. The striations in these simulations have magnitudes and meridional scales comparable to those reported from time-averaged altimeter observations and model output in...
A formalism recently developed for determining the effects of sampling errors on objectively smoothed fields constructed from an irregularly sampled dataset is applied to investigate the relative merits of single and multiple satellite altimeter missions. For small smoothing parameters, the expected squared error of smoothed fields of sea surface height...
A mechanism by which long planetary waves in the ocean may propagate significantly faster than the classical long baroclinic Rossby waves is investigated. The mechanism depends on the poleward thickening of intermediate density layers and the concomitant thinning of near-surface and deep layers. These features of the mass distribution are...
The wind speed and significant wave height (H1/3) dependencies of the sea state is in altimeter estimates of sea level, expressed in the form ∆hSSB=bH1/3, are examined from least squares analysis of 21 cycles of collinear TOPEX data. The bias coefficient b is found to increase in magnitude with increasing...
Planetary or Rossby waves are the predominant way in which the ocean adjusts on long (year to decade) timescales. The motion of long planetary waves is westward, at speeds ≥1 cm s⁻¹ . Until recently, very few experimental investigations of such waves were possible because of scarce data. The advent...
To understand the characteristics of sea surface height signatures of tropical instability waves (TIWs), a linearized model of the central Pacific Ocean was developed in which the vertical structures of the state variables are projected onto a set of orthogonal baroclinic eigenvectors. In lieu of in situ current measurements with...
Wind stress variability over the Benguela upwelling system is considered using 16 months (01 August 1999 to 29 November 2000) of satellite-derived QuikSCAT wind data. Variability is investigated using a type of artificial neural network, the self-organizing map (SOM), and a wavelet analysis. The SOM and wavelet analysis are applied...
3) The standard deviations of the SST anomalies in the HadISST1.1 dataset are 0.2–0.4°C smaller prior to 1949 than after 1949. This nonstationarity could complicate interpretations of the long HadISST1.1 data record for some studies of climate variability. It is likely attributable mostly to the improved sampling of SST observations...