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 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...
Motivated by satellite altimeter observations of enhanced sea level variability near steep topographic slopes in the Southern Ocean, effects of topography on the spatial distribution of mesoscale eddies and on eddy–mean flow interaction are investigated using a two-layer, wind-forced, quasigeostrophic channel model. The principal topography, a zonal ridge with a...
Global 1° × 1° climatologies of the first baroclinic gravity-wave phase speed c¹ and the Rossby radius of deformation λ1 are computed from climatological average temperature and salinity profiles. These new atlases are compared with previously published 5° × 5° coarse resolution maps of λ₁ for the Northern Hemisphere and...
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...
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...
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...
Alias periods and wavelengths for the M2, S2, N2, K1, O1, and P1 tidal constituents are calculated for TOPEX/POSEIDON. Alias wavelengths calculated in previous studies are shown to be in error, and a correct method is presented. With the exception of the K1 constituent, all of these tidal aliases for...
A simple statistic is derived for quantifying the potential for the aliasing of tidal errors in a given linear estimate of sea surface height constructed from altimeter data. The existence of M2 tidal constituent errors in Geosat data processed in the traditional way (i.e., with orbit errors removed using least...
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...
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...
Seasat scatterometer and altimeter data are analyzed to investigate time-dependent Sverdrup dynamics in the Southern Ocean (40°S to 60°S) over seasonal time scales. Sverdrup dynamics are shown to be inadequate to describe the circulation in the South Atlantic and Indian oceans. The Sverdrup circulation in the South Pacific is reasonable...
A formalism is presented for quantifying the sampling error of an arbitrary linear estimate of a time-averaged quantity constructed from a time series of irregularly spaced observations at a fixed location. The method is applicable to any irregularly sampled time series; it is applied here to satellite observations of chlorophyll...
The sea-state bias in Geosat altimeter range measurements expressed as a percentage of significant
wave height (SWH) is examined as a function of SWH. The bias is shown to be approximately
a fixed -3.5% of SWH for SWH smaller than about 4 m. For larger SWH, the bias decreases in...
A Geosat altimeter wind speed algorithm is derived by cross-calibrating Geosat and Seasat
altimeter estimates of the normalized radar cross section σ₀ and modifying an existing Seasat
altimeter wind speed model function to obtain a model function appropriate for Geosat observations.
It is argued that the σ₀ distribution measured by...
The variability of sea level and surface geostrophic currents in the Southern Ocean is investigated from the first 26 months of unclassified Geosat altimeter data (November 1986 to December 1988). Because of problems unique to Geosat, it has been necessary to develop new techniques for analyzing the height data. These...
Three months of vector wind observations from the Seasat-A satellite scatterometer (SASS) are used to construct gridded fields of monthly average wind stress and wind stress curl over the global ocean. These fields are examined to identify features either poorly resolved or not present in wind stress fields constructed from...