摘要:

During the coastal upwelling in 1974 the ocean temperature along the coast of Ghana exhibited periodic variations at a frequency of 0.07 cpd which propagated westward along the coast. Equatorial, shelf, and Kelvin waves are discussed, and it is found that the wave could be described in terms of any of these types of waves. However in the light of current theories of energy exchange in coastal waves the oscillation is most likely to be an internal Kelvin wave.

ISSN:0148-0227    

DOI:10.1029/JC081i024p04423

年代:1976

数据来源: WILEY

摘要:

The salient properties of the electric field intensity from first and subsequent lightning return strokes in the 0‐to 25‐km distance range near Gainesville, Florida, are presented, including electric field wave shape versus distance, initial peak rise time versus distance, rise time histograms, initial peak magnitude versus distance, normalized (to 100 km) initial peak magnitude histograms, normalized initial peak magnitude versus rise time, ramp starting time versus distance, and field at 170 μs versus distance. The mean normalized initial peak field for first return strokes was 9.9 V/m and for subsequent strokes, 5.7 V/m. The maximum measured values of normalized initial peak field were about 30 V/m. The largest field recorded at 170 μs was about 25 kV/m generated by a first stroke within 0.5 km. Return strokes were found to lower a typical charge of the order of 1 C in 1

ISSN:0148-0227    

DOI:10.1029/JC081i024p04430

年代:1976

数据来源: WILEY

摘要:

Estimates of solar radiation at the earth's surface are given based on a parameterization technique which employs 24 months of satellite‐derived cloud cover data (Sadler, 1969) and surface radiation measurements with established calibration traceability to the International Pyrheliometric Scale (1956). The zonal average solar radiation is presented as monthly and annual averages for each 2.5° from 30°N to 30°S. The global average solar radiation at the earth's surface is determined from the present study together with data from Ashbel (1961) and London and Sasamori (1971) as 0.286 cal/cm2min. This value and satellite measurements of global albedo suggest that the most likely values for the global solar radiation terms are (in proportion to that intercepted by the earth) 0.29 reflected to space, 0.19 absorbed by the atmosphere, and 0.52 absorbed by the earth's surface. The implications of the present study to the climatic model results of Budyko (1968) and Sellers (1969) are consid

ISSN:0148-0227    

DOI:10.1029/JC081i024p04435

年代:1976

数据来源: WILEY

摘要:

Oceanographic measurements made in the spring through holes in the ice in an area off Barrow, where the Barrow Canyon forms a sloping trough from the shallow Chukchi Sea into the deep Beaufort Sea, have revealed two interacting water movements: (1) a flow of highly saline water from the shallow Chukchi Sea into the Beaufort Sea through the Barrow Canyon and (2) an uprising of Atlantic water from the depths of the Beapfort Sea into the Barrow Canyon.

ISSN:0148-0227    

DOI:10.1029/JC081i024p04445

年代:1976

数据来源: WILEY

摘要:

The possibility of significant losses of chlorofluoromethanes and their photochemical products in the troposphere or stratosphere has been examined. A number of laboratory measurements have been carried out involving possible ambient positive and negative ions and CFCL3, CF2Cl2and HCl. No reactions between ions expected to have significant concentrations and these species have been observed. It appears that the reactions which might have been important are in fact endothermic. This is a result of normal atmospheric chemistry leading to very stable ions on a very short time scale. We conclude that ionmolecule reactions do not play a significant role in restricting the lifetime of CFCl3or CF2Cl2in the atmosphere or in removing the reactive products Cl, HCl, and ClO.

ISSN:0148-0227    

DOI:10.1029/JC081i024p04454

年代:1976

数据来源: WILEY

摘要:

A multislit channel isolator with narrow vertical and wide horizontal fields of view has been used on a high‐speed streaking camera to measure two‐dimensional return stroke velocities within 1 km of the ground. The slits serve to isolate small vertical sections of the return stroke channel of the order of tens of meters. The isolated sections in the object plane are separated by a vertical distance of the order of a few hundred meters. Data are obtained at a writing rate of 8.5×104mm s−1with a time resolution of 2.3 μs.All film was calibrated for the emulsion's nonlinear response to light. Measurements of 12 strokes in three multistroke flashes yield return stroke velocities which range from 2×107to 12×107m S−1with an estimated systematic error which varies from 30 to 60%. Velocities in one multistroke flash vary by a factor of 4 between the lowest and highest values. A higher relative intensity was detected in the upper parts of the channel relative to the lower. This may reflect the greater excitation of neutral atomic species in the upper channel and is a characteristic of lightning photographs obtained with red extended photographi

ISSN:0148-0227    

DOI:10.1029/JC081i024p04461

年代:1976

数据来源: WILEY

摘要:

Ice distribution and motion in the Bering Sea from March to June 1974 were observed by imagery from the NOAA 2 and 3 VHRR (very high resolution radiometer) satellites. The southerly ice edge was nearly constant in position from March to mid‐May, when ice disintegration had progressed to a point where the edge was undefined. Ice movement was southerly in response to northerly winds until late April, after which variable ice motion reflected variable winds. The southerly motion created regions of ice divergence south of islands and along east‐west trending southern coasts. In some areas such as the Bering Strait, water motion exerted sufficient stress on the ice to balance the wind.stress, resulting in stationary ice or northerly ice motion. The Bering Sea ice cover is conceptualized as northern source and southern sink regions connected by an intermediate zone of southerly ice motion. A mean observed southerly ice motion of 18 cm s−1requires heat losses for ice formation of the order of 10 g‐cal m−2s−1or an order of magnitude greater if most ice is assumed to form in divergent areas covered by thin ice or that have open water. These values are in agreement with previous estimates of sea‐air heat flux

ISSN:0148-0227    

DOI:10.1029/JC081i024p04467

年代:1976

数据来源: WILEY

摘要:

A mid‐latitude northern hemisphere model of the daytime ozone distribution in the troposphere, stratosphere, and lower mesosphere has been constructed. Data from rocket soundings in the latitude range of 45°N±15°N, results of balloon soundings at latitudes from 41° to 47°N, and latitude gradients from satellite ozone observations have been combined to produce estimates of the annual mean ozone concentration and its variability at heights up to 74 km for an effective latitude of 45°N. This model is a revision for heights above 26 km of the tentative mid‐latitude ozone model, included in theU.S. Standard Atmosphere Supplements, 1966, and has been adopted for use in theU.S. Standard Atmosph

ISSN:0148-0227    

DOI:10.1029/JC081i024p04477

年代:1976

数据来源: WILEY

摘要:

Surface waves due to rain are studied in the laboratory. The rms surface deviation is found to vary asκd/gv, where κ is rain kinetic energy flux,dis drop size,gis gravity, andvis viscosity. Wave spectra are quite sharp, and amplitude distributions appear to be Rayleigh in nature, at least in a qualitative sense. The logarithmic wind profile surface roughnessz0for rain in light winds is estimated and is found to be much larger than that due to the wind alon

ISSN:0148-0227    

DOI:10.1029/JC081i024p04482

年代:1976

数据来源: WILEY

摘要:

The average annual volume of United States precipitation is calculated to be 5759 km3for the 41‐yr period from 1931 through 1971 inclusive, the standard deviation being ±7.1%. The extremes are 15% (1957) and −14% (1956). Significantly, while wet years are more numerous than dry years, dry years are,on the average, drier than wet years are

ISSN:0148-0227    

DOI:10.1029/JC081i024p04485

年代:1976

数据来源: WILEY