Small scale inhomogeneity and intermittency of surface scattering during the 1992 Gulf of Alaska surface scatter and air–sea interaction experiment

1992 ◽  
Vol 92 (4) ◽  
pp. 2479-2479
Author(s):  
Richard G. Adair ◽  
Michael E. Huster ◽  
Donald W. Miklovic
Keyword(s):  
Gulf Of Alaska ◽  
Surface Scattering ◽  
Small Scale ◽  
Interaction Experiment ◽  
Scale Inhomogeneity ◽  
Surface Scatter

Chemistry, small-scale inhomogeneity, and formation of moldavites as condensates from sands vaporized by the Ries impact

2005 ◽  
Vol 69 (23) ◽  
pp. 5611-5626 ◽  
Author(s):  
Wolf von Engelhardt ◽  
Christoph Berthold ◽  
Thomas Wenzel ◽  
Thomas Dehner
Keyword(s):  
Small Scale ◽  
Scale Inhomogeneity

Tidal calibration of borehole strain meters: Removing the effects of small-scale inhomogeneity

1996 ◽  
Vol 101 (B11) ◽  
pp. 25553-25571 ◽  
Author(s):  
R. H. G. Hart ◽  
M. T. Gladwin ◽  
R. L. Gwyther ◽  
D. C. Agnew ◽  
F. K. Wyatt
Keyword(s):  
Small Scale ◽  
Scale Inhomogeneity

scholarly journals Wind-profiler observations of gravity waves produced by convection at mid-latitudes

2006 ◽  
Vol 6 (10) ◽  
pp. 2825-2836 ◽  
Author(s):  
Y. G. Choi ◽  
S. C. Lee ◽  
A. J. McDonald ◽  
D. A. Hooper
Keyword(s):  
Gravity Waves ◽  
Vertical Velocity ◽  
Small Scale ◽  
Wind Profiler ◽  
Convective Activity ◽  
Velocity Fluctuations ◽  
Short Period ◽  
Horizontal Momentum ◽  
Scale Inhomogeneity

Abstract. This work presents a case study which includes regions of large rapidly varying vertical velocities observed by a VHF wind-profiler at Aberystwyth (52.4° N, 4.1° W). Analysis indicates that this region is associated with gravity waves above the tropopause level and simultaneous regions of convective activity below the tropopause level. This case study also suggests that convective activity can be identified effectively by finding periods of large uncertainties on the derived velocities. These regions are hypothesized to be related to regions of small-scale inhomogeneity in the wind field. Examination suggests that the large vertical velocity fluctuations above these convective regions are short period gravity wave packets as expected from theory. In addition the vertical flux of the horizontal momentum associated with the gravity waves also displays the pattern of reversal observed in previous studies.

Spatial Distribution of Pacific Halibut (Hippoglossus stenolepis): An Application of Geostatistics to Longline Survey Data

1994 ◽  
Vol 51 (7) ◽  
pp. 1506-1518 ◽  
Author(s):  
Dominique Pelletier ◽  
Ana M. Parma
Keyword(s):  
Spatial Distribution ◽  
Spatial Structure ◽  
Large Scale ◽  
Survey Design ◽  
Gulf Of Alaska ◽  
Small Scale ◽  
Spatially Correlated ◽  
Pacific Halibut ◽  
Hippoglossus Stenolepis ◽  
Geostatistical Techniques

The spatial distribution of Pacific halibut (Hippoglossus stenolepis) in the Gulf of Alaska was analyzed using longline catch per unit of effort (CPUE) data collected during three grid surveys in 1984, 1985, and 1986. Geostatistical techniques were used: (i) a variographic analysis to model and estimate the spatial structure of halibut abundance and (ii) ordinary kriging to predict local abundance. Available small-scale information made it possible to model satisfactorily the spatial structure. Results show (i) a persistent large-scale east–west difference in average CPUE and (ii) spatially correlated CPUE data with an average covariance decreasing as the distance between observations increased, over a range of 0–20 nautical miles (nmi) in 1984 and 1985, and 50 nmi in 1986. The survey design had limitations in that it was too unbalanced, with stations very close together along north–south transects, and transects too far apart from each other. Consequently, prediction error was small close to the transects and large in between in a clear banded pattern. To achieve a more regular coverage of the same area, a new survey design was developed: the global variances obtained with this new design using the variogram parameters for 1985 and 1986 were 20% lower than those based on the old design.

The structure of the turbulent atmospheric boundary layer

1983 ◽  
Vol 308 (1503) ◽  
pp. 291-309 ◽  
Keyword(s):  
Boundary Layer ◽  
Atmospheric Boundary Layer ◽  
Ekman Layer ◽  
Momentum Balance ◽  
Small Scale ◽  
Mean Flow ◽  
Vertical Fluxes ◽  
Research Aircraft ◽  
Interaction Experiment ◽  
Representative Area

During the Joint Air-Sea Interaction Experiment (JASIN), mean flow and turbulent fluctuations were measured throughout the depth of the atmospheric boundary layer by shipborne surface instrumentation, multiple-instrument packages suspended from tethered balloons and research aircraft flying in low level formation. These enabled both individual localized events and representative area-average (70 km x 70 km) measurements to be investigated. The results are summarized and show that continuous small-scale turbulent mixing was generally confined to an Ekman layer a few hundred metres deep. The structure of this layer is examined in detail, particularly the momentum balance. Spectral analysis reveals two energy-containing regions, one of which, at higher wavenumbers, scales with the Ekman layer depth and carries most of the vertical fluxes. Direct coupling between the Ekman layer and the overlying atmosphere is weak and appears to be strongly dependent on cloud processes, which are intermittent and irregularly distributed on the scale of these measurements.

scholarly journals A Comparison of Statistical Dynamical and Ensemble Prediction Methods during Blocking

2008 ◽  
Vol 65 (2) ◽  
pp. 426-447 ◽  
Author(s):  
Terence J. O’Kane ◽  
Jorgen S. Frederiksen
Keyword(s):  
Kinetic Energy ◽  
Numerical Simulations ◽  
Direct Interaction ◽  
Gulf Of Alaska ◽  
Direct Numerical Simulations ◽  
Ensemble Prediction ◽  
Small Scale ◽  
Error Growth ◽  
Closure Model ◽  
Non Gaussian

Abstract In this paper error growth is examined using a family of inhomogeneous statistical closure models based on the quasi-diagonal direct interaction approximation (QDIA), and the results are compared with those based on ensembles of direct numerical simulations using bred perturbations. The closure model herein includes contributions from non-Gaussian terms, is realizable, and conserves kinetic energy and enstrophy. Further, unlike previous approximations, such as those based on cumulant-discard (CD) and quasi-normal (QN) hypotheses (Epstein and Fleming), the QDIA closure is stable for long integration times and is valid for both strongly non-Gaussian and strongly inhomogeneous flows. The performance of a number of variants of the closure model, incorporating different approximations to the higher-order cumulants, is examined. The roles of non-Gaussian initial perturbations and small-scale noise in determining error growth are examined. The importance of the cumulative contribution of non-Gaussian terms to the evolved error tendency is demonstrated, as well as the role of the off-diagonal covariances in the growth of errors. Cumulative and instantaneous errors are quantified using kinetic energy spectra and a small-scale palinstrophy production measure, respectively. As a severe test of the methodology herein, synoptic situations during a rapid regime transition associated with the formation of a block over the Gulf of Alaska are considered. In general, the full QDIA closure results compare well with the statistics of direct numerical simulations.

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