摘要:

Over 2800 mean wind profiles (data from two mobile micrometeorological stations near Dallas, Texas) were analyzed to test the Monin‐Obukhov similarity hypothesis as expressed by the log‐linear wind profile. Wind speed and temperature data for eight levels between 25 cm and 32 m were averaged for 5‐ and 25‐min periods. The Monin‐Obukhov parameter α′, which is the coefficient of the linear term in the profile, was found to be a function of stability varying from 0.2 to 3.0 in lapse conditions and from 9 to 3 during inversion conditions. However, practical values of α′ for lapse (0.6) and inversions (5.0) conditions are suggested for forecasting mean diabatic wind profiles. The Obukhov ‘gradient length’L' was found to be a function of height above the ground; therefore, it does not possess complete dynamic similarity. The broad applicability of the log‐linear profile is shown by calculating residual variances for each profile as a function of height, wind speed, and stability. An empirical log‐power profile was also tested. The preferred power for the diabatic term was unity (or larger) for inversion conditions and approximately 0.5 for lapse conditions. Since the standard error of estimate of the wind speed based on the log‐linear profiles was not significantly greater than that based on log‐power for the latter case, the log‐linear profile appears to be adequ

ISSN:0148-0227    

DOI:10.1029/JZ070i010p02277

年代:1965

数据来源: WILEY

摘要:

Dilute solutions (2.5×10−4M) of potassium fluoride, cesium fluoride, and lithium iodide were frozen at rates from approximately 1 to 20 μ/sec. A chemical analysis of the melted ice and of the supernatant liquid was made, and the electrical potentials or currents generated were measured. During the freezing, ionic transfer processes take place at the ice‐solution interface which are a function of ionic species present, their concentration, and the freezing rate. These processes are ionic rejection and incorporation, ionic separation, and ionic neutralization. In all three solutions, the anion is incorporated in greater numbers than the cation, regardless of the relative ionic sizes. The difference between incorporated halogen anions and incorporated alkali cations is made up with hydrogen ions, supplied either from the freezing base (shunt case) or from the liquid (open‐circuit case) or both. The relation between the rates of freezing and of ionic transfer determines the extent of this replacement. Ice samples grown from potassium‐ and cesium‐fluoride solutions with a low‐resistance external shunt show a direct‐current conductivity on the average about four times greater than samples grown without a shunt. Trace impurities, growth rate, and phase‐boundary conditions during growth are determining factors of the electrical bulk

ISSN:0148-0227    

DOI:10.1029/JZ070i010p02291

年代:1965

数据来源: WILEY

摘要:

A small, accurate, inexpensive instrument to integrate daily solar radiation flux density can be constructed using two or more silicon solar cells and a Curtis mercury integrator. Maximum error is less than 200 watt hr m−2over a 1‐day period, out of a possible total of 8000 watt hr m−2on a clear day. Response is linear, temperature sensitivity is low, and cosine response does not cause serious error except at high lat

ISSN:0148-0227    

DOI:10.1029/JZ070i010p02301

年代:1965

数据来源: WILEY

摘要:

Two methods for estimating mean monthly anomalies of sea‐surface temperature from contemporaneous patterns of mean‐sea‐level pressure were evaluated for the eastern North Pacific. One method involves the computation of anomalous displacement of surface water masses implied by the drag of surface winds (based on geostrophic computations from sea‐level pressure anomalies) and the normal fields of sea‐surface temperature. The other method adds to this persistence of the sea temperature taken from the preceding month. The results of statistical tests on a 2‐year sample indicate some degree of success for both methods, but appreciable superiority for the latter. Examples are shown. The partial success of such coarse methods holds out the hope for improved specifications and perhaps forecasts of sea‐surface temperatures, which would greatly assist in both oceanographic and meteorolo

ISSN:0148-0227    

DOI:10.1029/JZ070i010p02307

年代:1965

数据来源: WILEY

摘要:

Internal waves of large amplitude were observed north of Sumatra by the U.S. Coast&Geodetic Survey shipPioneerin June 1964. The bathythermograph investigation which defined these waves was initiated after observation of curious periodic surface phenomena resembling tide rips. Analysis of bathythermograph records indicates that internal waves with a maximum observed wave height of 82 meters are the probable cause of the surface disturbances.

ISSN:0148-0227    

DOI:10.1029/JZ070i010p02319

年代:1965

数据来源: WILEY

摘要:

The damping of small‐amplitude surface waves on a viscous fluid over a permeable fixed bed is studied. Conservation arguments and consideration of the rate of doing work at the fluid‐bed interface are applied in a careful analysis of the boundary conditions at the interface. It is shown that stresses are not continuous at the interface. A general dispersion relationship, which gives the damping characteristics for given wave parameters, is found together with the stream functions for the flow in the two regimes. The wave damping characteristics are different from those given in previous studies of waves over a permeable fixed bed and are a consequence of the new boundary conditions derived below. The damping effects due to percolation in the fixed bed are not always small in comparison with the viscous effects. Some numerical examples of typical situations are gi

ISSN:0148-0227    

DOI:10.1029/JZ070i010p02325

年代:1965

数据来源: WILEY

摘要:

The use of radioactive tracers in previous studies has demonstrated that appreciable water movement can occur in ice‐covered lakes. Mathematical evaluation of these results shows that the vertical component of this motion can be calculated and is between one and three orders of magnitude less than the horizontal component. The over‐all pattern of circulation is consistent with convective motion caused by heating from below. Sources of heat in the sediments are considered and evaluated. Because of the organized nature of the circulation observed beneath the ice cover, the validity of classical terminology such as ‘winter stagnation’ and ‘dimixis’ is

ISSN:0148-0227    

DOI:10.1029/JZ070i010p02333

年代:1965

数据来源: WILEY

摘要:

The experimentally measured dependence of the mean radar power backscattered from the lunar surface on the angle of incidence (delay time) is compared with the theoretical formula based on a lunar surface consisting of a superposition of several normal random processes of different structures. The theoretically derived curve accounts for shadowing and matches the experimental data over almost the entire range of angles of incidence to within ±1 db. The wavelength dependence is also consistent with the observed data as far as they are available. The analysis yields a value of 11° for the rms slope of the lunar surfac

ISSN:0148-0227    

DOI:10.1029/JZ070i010p02345

年代:1965

数据来源: WILEY

摘要:

Infrared spectral emission was obtained for various thicknesses of Teflon, Mylar, and Dupont film H at temperatures below 100°C. Characteristic data are apparent for samples which exceed the thickness limits imposed by Hovis. The use of an uncooled detector to obtain such characteristic spectral data at long wavelengths (out to 40 μ) is demonstrated. Thus, it should be possible to obtain diagnostic spectral emission from the surface of the planet Mars by using proper instruments aboard a Mars prob

ISSN:0148-0227    

DOI:10.1029/JZ070i010p02351

年代:1965

数据来源: WILEY

摘要:

In his interpretation of my original remarks Hunt has missed the point that the requirements for detector cooling were for a spacecraft mission to Mars, Detection of emission features from specimens at 85 to 95°C in the laboratory with ample time to make the observations is a far different problem from that encountered when viewing the surface of a planet with expected temperatures in the 200 to 270°K range with scan times of the order of 1 minute per spectrum.Detector cooling is necessary to produce acceptable signal‐to‐noise ratios when measuring the spectrum of such a weak thermal source. The comparison of detectors presented seems to be based on the blackbody detectivity of the various detectors and as such means little when comparing detectors for spectral scanning. When the observed radiation is attenuated by devices such as spectrometers or filters, the only valid comparison is made by the use of the spectral detectivity. Comparison of the spectral detec‐ tivities of presently available detectors indicates that cooled, doped germanium detectors maintain an advantage of approximately an order of magnitude over room temperature detectors from 5

ISSN:0148-0227    

DOI:10.1029/JZ070i010p02359

年代:1965

数据来源: WILEY