Tidal phenomena in the Indonesian
seas are among the most complex in the
world. Complicated coastal geometries
with narrow straits and myriad small islands,
rugged bottom topography next to
wide shelves of shallow water, and large
quantities of tidal power input from the
adjoining Indian and Pacific Oceans—all
combine to...
The Oregon Coastal Transition Zone (OCTZ) extends several hundred
kilometers offshore where shelf flows interact with the northern California Current. A
primitive-equation numerical ocean model is used to study the upwelling circulation in this
region from 1 May to 1 November 2001. This OCTZ model obtains initial and boundary
conditions...
We assimilate localized mass anomalies inferred from
GRACE ranging measurements into a hydrodynamic model
to improve tidal solutions around Antarctica for the M2, S2,
and O1 constituents. The variational approach used accounts
for the spatial averaging of tidal elevations implicit in the
mass anomaly parametrization used for the GRACE tidal...
Horizontal current measurements from an array of moored acoustic Doppler profilers are assimilated sequentially into a model of coastal wind-driven circulation off Oregon during the upwelling season of May–August 2001. Model results are compared against independent moored and ship survey data to document a positive effect of velocity data assimilation...
Magnetotelluric (MT) data from two sites 150 and
300 km southeast of San Francisco, California (geomagnetic
dipole latitude: 43 degrees, L approximately 1.9) show that
the usual MT assumption of spatially uniform external magnetic
fields is violated to a significant degree in the period
range 10-30 s. Inter-station transfer functions...
New empirical estimates of the long-period fortnightly (Mf) tide obtained from TOPEX/Poseidon (T/P) altimeter
data confirm significant basin-scale deviations from equilibrium. Elevations in the low-latitude Pacific
have reduced amplitude and lag those in the Atlantic by 308 or more. These interbasin amplitude and phase
variations are robust features that are...
An optimal interpolation (OI) sequential algorithm is implemented for a three-dimensional primitive equation model to assimilate current measurements from acoustic Doppler profilers moored on the Oregon shelf as a part of the Coastal Ocean Advances in Shelf Transport (COAST) upwelling experiment (May–August 2001). A stationary estimate of the forecast error...
A computationally efficient relocatable system for generalized inverse (GI) modeling of barotropic ocean tides is described. The GI penalty functional is minimized using a representer method, which requires repeated solution of the forward and adjoint linearized shallow water equations (SWEs). To make representer computations efficient, the SWEs are solved in...
Although satellite electromagnetic induction studies
have usually assumed a symmetric magnetospheric ring
current source, there is growing evidence for significant
source asymmetry. Here we apply empirical orthogonal
function methods to mid-latitude night-side hourly mean
geomagnetic observatory data to search for evidence of nonzonal
low-frequency source fields. The dominant spatial
mode...
The most accurate determinations of the global ocean tides are currently based on altimeter measurements made by the Topex/Poseidon satellite. The error spectrum corresponding to the M₂ tidal solution is here estimated, primarily by inverse methods and secondarily by simple differencing in flatter than tidal signal spectrum, and it exceeds...
Most of the tidal energy dissipation in the ocean occurs in shallow seas, as had long been recognized. However, recent work has suggested that a significant fraction of the dissipation, perhaps 1 TW or more, occurs in the deep ocean. This paper builds further evidence for that conclusion. More than...
The current satellite magnetic missions offer new
opportunities to determine the electrical conductivity of the
Earth. However, satellites are nearly stationary in local time
and therefore sample the inducing and induced fields quite
differently than geomagnetic observatories, which rotate
with the Earth. We show that estimates of induction transfer
functions...
The small S₁ ocean tide is caused primarily by diurnal atmospheric pressure loading. Its excitation is therefore unlike any other diurnal tide; in particular, pressure loading is maximum near the equator where the diurnal gravitational potential is zero. The global character of the S₁ tide is here determined by numerical...
A linearized baroclinic, spectral-in-time tidal inverse model has been developed for assimilation of surface currents from coast-based high-frequency (HF) radars. Representer functions obtained as a part of the generalized inverse solution show that for superinertial flows information from the surface velocity measurements propagates to depth along wave characteristics, allowing internal...