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X. Lee H.H. Neumann G. Hartog R.E. Mickle J.D. Fuentes T.A. Black P.C. Yang P.D. Blanken 《Boundary-Layer Meteorology》1997,84(3):383-398
In this paper we report the results of the analysis of two 60-min wave events that occurred in a boreal aspen forest during the 1994 BOREAS (Boreal Ecosystems-Atmosphere Study) field experiment. High frequency wind and temperature data were provided by three 3-D sonic anemometer/thermometers and fourteen fine-wire thermocouples positioned within and above the forest. Wave phase speeds, estimated from information revealed by spectral analysis and linear plane wave equations, are 2.2 and 1.3 m s-1 for the two events. The wavelengths are 130 m and 65 m respectively and are much larger than the vertical wave displacements. There is strong evidence from the present analysis and from the literature supporting our postulate that these waves are generated by shear instability. We propose that wind shear near the top of the stand is often large enough to reduce the gradient Richardson number below the critical value of 0.25 and thus is able to trigger the instability. When external conditions are favorable, the instability will grow into waves. 相似文献
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Abstract During the GARP Atlantic Tropical Experiment (GA TE) in the summer of 1974, identical tethersonde packages were flown to heights of 1,000 m from two ships with a crosswind separation of approximately 4 km. The differences in the profiles and fixed level time series from the two packages are a measure of spatial variability in the tropical marine boundary layer. Correlation analysis indicate a cellular pattern in the large‐scale wind field. Similar analyses of the temperature and humidity fields give quite different results. 相似文献
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Abstract The relationships between monthly anomalies of sea surface temperature (SST) and monthly anomalies of several surface wind parameters are examined using ten years of data from the mid‐latitude North Pacific Ocean. The wind parameters involve both u3 * and curl τ, where u* is the atmospheric friction velocity and τ the surface stress. These quantities are calculated from surface wind components analysed on synoptic (6‐hourly) maps. In order to examine the effect of synoptic disturbances, the time series of surface wind components at each grid point is high‐pass filtered (passing periods less than 10 days) and the above wind parameters are calculated from both filtered and unfiltered wind components. Two statistically significant relationships are found between monthly anomalies of SST and those of the various wind parameters. The first is a large coherent negative correlation between monthly anomalies of u3 * calculated from the high‐pass filtered wind components and month‐to‐month changes in the SST anomalies in the Central Pacific. This relationship is attributed to the production of turbulent vertical mixing in the ocean by synoptic disturbances in the atmosphere. The second relationship is a large positive correlation between curl τ calculated from the unfiltered wind components and SST anomaly changes in the Eastern Pacific. This relationship, which is opposite to that expected from Ekman pumping, is attributed to a negative association between the wind stress curl and the meridional advection of heat by the eastern boundary current system. It is shown that these atmospheric forcing mechanisms explain up to 10 per cent of the variance of monthly SST anomalies in a large part of the mid‐latitude North Pacific Ocean. This amount is in addition to, but certainly less than, that which can be explained by anomalous horizontal advection through statistical relationships with sea‐level pressure anomalies (Davis, 1976). 相似文献
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Stephen T. Ross W. Todd Slack Ryan J. Heise Mark A. Dugo Howard Rogillio Bryant R. Bowen Paul Mickle Richard W. Heard 《Estuaries and Coasts》2009,32(2):360-374
Gulf sturgeon are anadromous, spawning in freshwater and returning to the marine environment to feed. Herein, we document
the marine distribution and timing of movement in and out of the marine environment of Gulf sturgeon natal to the Pascagoula
and Pearl rivers (MS and LA). From 1999 to 2004, we attached sonic transmitters to 194 fish averaging 151 (MS) to 160 (LA)
cm in fork length. We located 56 different Gulf sturgeon in the estuarine or marine environments, some multiple times. Fish
were distributed nonrandomly, being found primarily in shallow water (mean = 3.9 m) in barrier island passes. Benthic samples
taken at Gulf sturgeon telemetry location sites were dominated by Florida lancelets, sand dollars, annelids, haustoriid amphipods,
and mollusks—all documented prey of Gulf sturgeon. Movement into salt water consistently occurred in October and November;
movement back into rivers or low salinity estuaries was complete by the end of March. 相似文献
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J. R. Salmon A. J. Bowen A. M. Hoff R. Johnson R. E. Mickle P. A. Taylor G. Tetzlaff J. L. Walmsley 《Boundary-Layer Meteorology》1988,43(3):247-271
This is one of a series of papers on the Askervein Hill Project. It presents results on the variations in mean wind speed at fixed heights (z) above the ground from linear arrays of anemometer posts and towers. Most of the data are for z = 10 m but some are for z = 3 m. Selected and directionally grouped data from the 55 Mean Flow runs are presented together with mean flow data from Askervein '83 Turbulence runs. Comparisons are made between the data and guideline estimates of fractional speed-up ratio at hilltop locations and between the data and MS3DJH/3 model predictions along the tower lines. There is good agreement in most cases. 相似文献
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Alarcon Vladimir J. Linhoss Anna C. Kelble Christopher R. Mickle Paul F. Sanchez-Banda Gonzalo F. Mardonez-Meza Fernando E. Bishop Joseph Ashby Steven L. 《Natural Hazards》2022,111(3):2933-2962
Natural Hazards - Southeast Florida (SF) is among the most vulnerable regions to sea-level rise in the United States of America. The consequences associated with sea-level rise (SLR) are already... 相似文献
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R. E. Mickle N. J. Cook A. M. Hoff N. O. Jensen J. R. Salmon P. A. Taylor G. Tetzlaff H. W. Teunissen 《Boundary-Layer Meteorology》1988,43(1-2):143-169
This is one of a series of papers on the Askervein Hill Project. It presents results from the Askervein 1982 and 1983 experiments
in the form of vertical profiles of mean wind and turbulence integral statistics at upwind reference locations and at two
hilltop sites. The data were obtained from a variety of sensors including sonic, Gill UVW and cup anemometers mounted on 50,
30, 17 and 10 m towers and TALA kite systems. Comparisons with numerical-model predictions are discussed. 相似文献
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J. R. Salmon H. W. Teunissen R. E. Mickle P. A. Taylor 《Boundary-Layer Meteorology》1988,43(4):309-343
Field observations of the influence of topography on steady, neutrally-stratified boundary-layer flow were carried out in February 1981 and March 1984 on Kettles Hill near Pincher Creek, Alberta, Canada. The primary measurements were of wind speed at 3,6, and 10 m levels at stations in linear arrays along and across the major axis of this gentle, 1 km long and 100 m high, elliptical hill. Wind profile measurements up to heights of 200 m were made with TALA kites and tethersondes on the hilltop and at a reference site located about 3.7 km west of the hilltop. In addition, AIRsondes were flown and tracked from the reference site to provide additional data. The field observations provided the basic data for a comparison with wind-tunnel and numerical model simulations of the same flow. The wind-tunnel investigation was carried out in the Atmospheric Environment Service Boundary-Layer Wind Tunnel while the numerical model used was MS3DJH. For horizontal profiles of normalized mean wind speed at given heights above the prototype terrain, model results agree reasonably well with the field data. The wind-tunnel predictions are slightly high in most cases. For vertical profiles of wind speed up to 200 m above the hilltop, the numerical and wind-tunnel values are higher than were observed. The sensitivity of the normalized wind speed at the hilltop to deviations from non-logarithmic upwind profiles is demonstrated with data from the March 1984 experiment. A comparison of prototype with numerical-model mean-wind-direction perturbations at the 10 m level shows reasonable agreement except near the summit of the hill.Contractor: 24 Heslop Drive, Toronto. 相似文献
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