Several investigators have recently called attention to the
fact that the flux equation for water movement in unsaturated soils
may not be an appropriate mathematical model for the development
of the theory of unsaturated flow phenomena.
An analytical theory is developed for the purpose of testing
the validity of the...
Published December 1963. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
Over 20 global ocean tide models have been developed since 1994, primarily as a
consequence of analysis of the precise altimetric measurements from TOPEX/POSEIDON and as a result of parallel developments numerical tidal modeling and data assimilation. This paper
provides an accuracy assessment of 10 such tide models and discusses...
The accuracy of state-of-the-art global barotropic tide models is assessed using bottom
pressure data, coastal tide gauges, satellite altimetry, various geodetic data on Antarctic ice shelves, and
independent tracked satellite orbit perturbations. Tide models under review include empirical, purely
hydrodynamic (“forward”), and assimilative dynamical, i.e., constrained by observations. Ten dominant...
Un Paseo Encantado, an enchanted walk, is a collection of my observations and experiences in a study abroad program in Oviedo, Spain. My commentary on Spanish culture is based on reading I did prior my departure, in combination with my observations while in Spain. In six chapters, I explore the...
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...
This study of the fortnightly Mf tide comprises three main topics: (1) a new determination of the fortnightly component of polar motion and length of day (LOD) from a multidecade time-series of observed space-geodetic data; (2) the use of the polar motion determination as one constraint in the development of...
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...
The Inverse Ocean Modeling (IOM) System is a modular system for constructing and running weak-constraint four-dimensional variational data assimilation (W4DVAR) for any linear or nonlinear functionally smooth dynamical model and observing array. The IOM has been applied to four ocean models with widely varying characteristics. The Primitive Equations Z-coordinate-Harmonic Analysis...
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...
We present a new, non-flux corrected AOGCM, GENMOM, that combines the GENESIS version 3 atmospheric GCM (Global Environmental and Ecological Simulation of Interactive Systems) and MOM2 (Modular Ocean Model version 2) nominally at T31 resolution. We evaluate GENMOM by comparison with reanalysis products (e.g., NCEP2) and three models used in...
The network comprising 61 high-frequency radar systems along the U.S. West Coast (USWC) provides a unique, high resolution, and broad scale view of ocean surface circulation. Subinertial alongshore surface currents show poleward propagating signals with phase speeds of O(10) and O(100–300) km d⁻¹ that are consistent with historical in situ...
The nearly completed U.S. West Coast (USWC) high-frequency radar (HFR) network provides an unprecedented capability to monitor and understand coastal ocean dynamics and phenomenology through hourly surface current measurements at up to 1 km resolution. The dynamics of the surface currents off the USWC are governed by tides, winds, Coriolis...
As part of the U.S. Joint Global Ocean Flux Study Southern Ocean
program, high-resolution surveys of the Antarctic Polar Front near 170øW were
conducted during October-November 1997 with a towed undulating system equipped
with conductivity-temperature-depth and bio-optical sensors. Transects along
170°W and two successive mapping surveys revealed zonal bands with...
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...
The overflow of deep water from the Nordic seas
into the North Atlantic plays a critical role in global ocean
circulation and climate. Approximately half of this overflow
occurs via the Iceland–Scotland (I–S) overflow, yet the history
of its strength throughout the Holocene (~0–11 700 yr
ago, ka) is poorly...
Full Text:
, R. H., and Stammer, D. B.: The sensi-
tivity of the Greenland-Scotland Ridge overflow to forcing
Most of the policy debate surrounding the actions needed to mitigate and adapt to anthropogenic climate change has been framed by observations of the past 150 years as well as climate and sea-level projections for the twenty-first century. The focus on this 250-year window, however, obscures some of the most...
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-millennial climate and sea-level change
Peter U. Clark1*, Jeremy D. Shakun2, Shaun A. Marcott3, Alan C. Mix1
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 globally integrated carbon observation and analysis
system is needed to improve the fundamental understanding
of the global carbon cycle, to improve our ability to
project future changes, and to verify the effectiveness of policies
aiming to reduce greenhouse gas emissions and increase
carbon sequestration. Building an integrated carbon observation...
Most of the kinetic energy of ocean circulation is contained in ubiquitous
mesoscale eddies. Their prominent signatures in sea surface height have rendered satellite
altimetry highly effective in observing global ocean eddies. Our knowledge of ocean eddy
dynamics has grown by leaps and bounds since the advent of satellite altimetry...
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...
Ten years of sea-surface height (SSH) fields constructed from the merged TOPEX/Poseidon (T/P) and ERS-1/2 altimeter datasets are analyzed to investigate mesoscale variability in the global ocean. The higher resolution of the merged dataset reveals that more than 50% of the variability over much of the World Ocean is accounted...
The use of grass cover crops is a recommended practice in
nonirrigated vineyards in the Willamette Valley, Oregon. Two
studies were initiated to investigate the competitive and
noncompetitive effects of grass cover crops on the growth and
development of Pinot noir grapevines. Two greenhouse pot culture
experiments were performed to...
This paper examines the effect of “stencil width” on surface ocean geostrophic velocity and vorticity estimated from differentiating gridded satellite altimeter sea surface height products. In oceanographic applications, the value of the first derivative at a central grid point is generally obtained by differencing the sea surface heights at adjacent...
An intermediate-complexity climate model is used to simulate the impact of an accelerated Pine Island Glacier mass loss on the large-scale ocean circulation and climate. Simulations are performed for preindustrial conditions using hosing levels consistent with present-day observations of 3000 m³ s⁻¹, at an accelerated rate of 6000 m³ s⁻¹,...
In this article the authors examine the kinematics and dynamics of the seasonal cycle in the western Indian Ocean in an eddy-permitting global simulation [Parallel Ocean Circulation Model, model run 4C (POCM-4C)]. Seasonal changes of the transport of the Agulhas Current are linked to the large-scale circulation in the tropical...
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...
High-resolution (km in space and hourly in time) surface currents observed by an array of high-frequency radars off Oregon are analyzed to quantify the decorrelation time and length scales of their near-inertial motions. The near-inertial surface currents are dominantly clockwise with amplitudes of 9-12 cm s⁻¹. However, they appear asymmetric...
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...
The exceptional feature of the brushless doubly-fed
machine is the lack of need for frequent replacement of
brushes. The inherent instability of this machine has to be
overcome for its application in adjustable speed drives and
variable speed generation systems.
Specific objectives were:
to study the characteristics of the machine...
This article investigates the origins of the variability of the Malvinas Current (MC)
transport using the results of an eddy-permitting ocean general circulation model. First, the
dynamical links between the variabilities of the MC and the Antarctic Circumpolar
Current (ACC) transports at the Drake Passage are established. Time series analyses...
Two ocean general circulation models are used to test the ability of geostrophic velocity measurement systems to observe the meridional overturning circulation (MOC) and meridional heat transport (MHT) in the South Atlantic. Model sampling experiments are conducted at five latitudes (between 15° and 34.5°S) spanning the range of extratropical current...
The surface wind stress response to sea surface temperature (SST) over the latitude range 30°–60°S in the Southern Ocean is described from the National Aeronautics and Space Administration's QuikSCAT scatterometer observations of wind stress and Reynolds analyses of SST during the 2-yr period August 1999 to July 2001. While ocean–atmosphere...
The formation mechanisms and pathways of intermediate water in the Southern Ocean are analyzed from output of a high-resolution ocean general circulation model. Deep winter mixed layer formation in the Southern Ocean is diagnosed from the model results and is found to be mostly consistent with observations. Diapycnal water mass...
We apply GENMOM, a coupled atmosphere–ocean climate model, to simulate eight equilibrium time
slices at 3000-year intervals for the past 21,000 years forced
by changes in Earth–Sun geometry, atmospheric greenhouse
gases (GHGs), continental ice sheets, and sea level. Simulated
global cooling during the Last Glacial Maximum
(LGM) is 3.8°C and...
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(GECCO
data; Köhl and Stammer, 2008). Although the T31 resolution
of GENMOM is a factor in limiting
Present methods used to retrieve altimeter data do not provide reliable estimates of
sea surface height (SSH) in the nearshore region, resulting in a measurement gap of
25–50 km next to the coast. In the present work, gridded SSH fields produced by
Archiving, Validation, and Interpretation of Satellite Oceanographic data...
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...
Projections of a drier, warmer climate in the U.S. Southwest would complicate
management of the Colorado River system – yet these projections, often based on coarse
resolution global climate models, are quite uncertain. We present an approach to understanding
future Colorado River discharge based on land surface characterizations that map...
The last deglaciation of the Scandinavian Ice Sheet (SIS) from ∼21,000 to 13,000 yr ago is well-constrained by several hundred ¹⁰Be and ¹⁴C ages. The subsequent retreat history, however, is established primarily from minimum-limiting ¹⁴C ages and incomplete Baltic-Sea varve records, leaving a substantial fraction of final SIS retreat history...
This study uses interviews with 18 businesses in Oregon's Willamette Valley to explore business investment in the environment, and how this relates to ecosystem services, payment for ecosystem services programs, and the water-energy nexus. Our research led us to outline 5 factors that influence business investment in the environment, those...
Published December 1941. Facts and recommendations in this publication may no longer be valid. Please look for up-to-date information in the OSU Extension Catalog: http://extension.oregonstate.edu/catalog
In this dissertation, I describe the experimental investigation of electron diffraction of neutral and ionic clusters doped into superfluid helium droplets. The project is aimed at contributing to the development of an overall approach called ‘serial single molecule electron diffraction imaging (ss-EDI), a potential approach to solve macromolecule structures bypassing...
The local and remote sources of variability of the South Atlantic Ocean are investigated using a set of numerical experiments and satellite data. A global, eddy-permitting, numerical simulation is analyzed to investigate the dynamical links between the Antarctic Circumpolar Current (ACC) and the Malvinas Current (MC). The model results indicate...
Air-sea interaction at ocean fronts and eddies exhibits positive correlation between sea surface temperature (SST), wind speed, and heat fluxes out of the ocean, indicating that the ocean is forcing the atmosphere. This contrasts with larger scale climate modes where the negative correlations suggest that the atmosphere is driving the...
A linearized model with two vertical modes has been developed to understand observed characteristics of monthly variability in the Equatorial Pacific from TOPEX/POSEIDON measurements of Sea Surface Height (SSH). The 2-mode model is obtained from an equatorial beta plane model that has been linearized about a geostrophically balanced mean flow...
Although it is well-established that the fatty acid profile of breast milk will
reflect the dietary fatty acids, the response time with which this occurs is not
known. We hypothesized that fatty acids from a given meal would be transferred
acutely from chylomicrons into breast milk. To test this hypothesis,...
• A technique for measuring in vitro respiration was investigated to understand why rates were higher than those reported in vivo and to elucidate trends within mature Pseudotsuga menziesii (Douglas‐fir) trees.
• Extracted increment cores were divided into 3–4 radial depths and a gas chromatograph was used to compare respiration...