摘要:

High‐resolution gamma ray spectroscopy has been used to obtain ratios of214Bi to214Pb specific activities for large volume air samples taken at a height of 20 m. Afternoon samples that were taken for a period of several months exhibited214Bi/214Pb ratios that ranged from 0 to 2.2 with a mean value of 0.67 ± 0.06. Observed214Pb specific activities for this group of samples ranged from 35.2 to 360.4 pCi/m3with a mean value of 122.8 pCi/m3. Most samples exhibiting214Bi/214Pb ratios greater than 1.0 were associated both with low values of214Pb specific activity and with the advection of maritime air during the sampling period. When samples taken during strong winds are excluded, a mean214Bi/214Pb activity ratio of 0.48 ± 0.08 is obtained. A smaller group of morning samples taken at the same location exhibited a mean214Bi/214Pb ratio of 0.70 ± 0.08. The results of these measurements have been compared with the predictions of turbulent diffusion th

ISSN:0148-0227    

DOI:10.1029/JC080i012p01605

年代:1975

数据来源: WILEY

摘要:

Eighteen close range tornado observations reveal that electrical activity near or within the funnel is far too infrequent to lend credence to electrical theories of tornado genesis and maintenance.

ISSN:0148-0227    

DOI:10.1029/JC080i012p01614

年代:1975

数据来源: WILEY

摘要:

A numerical model of the atmosphere with a seasonal variation of insolation and sea surface temperature is time integrated for over 3 simulation years on a finite difference grid network having a nearly uniform horizontal resolution of approximately 265 km. There are 11 levels in the model from 80 m to 31 km above the ground. The model has realistic continents with smoothed topography. In addition to wind, temperature, pressure, and water vapor, the model simulates rainfall, snowfall, and evaporation at the surface. The runoff rate and the rates of change of soil moisture and snow depth are determined by a budget of liquid water, snow, and heat at the ground surface. The simulated precipitation and other hydrologic quantities are compared with those derived from observed data. In addition, the correspondence between the distribution of precipitation rate and those of other relevant quantities, such as sea level pressure and kinetic energy of transient disturbances, is examined. To obtain an overall impression of the climate simulation, a map of Köppen climate types, which is obtained from simulated temperatures and precipitation rates throughout the year, is compared with a similar map based upon observed climatic data. It is shown that the model locates the major arid regions of the earth, such as the Sahara Desert in northern Africa and the deserts of central Asia and Australia. Furthermore, the tropical rain belt and its seasonal movement are well reproduced. The model approximately simulates the changeover from dry winter to wet summer conditions in southern Asia and the seasonal reversal of the monsoon wind system over Asia. The wet zone in middle and high latitudes, such as in Canada, Europe, and western Siberia, is also simulated by the model. Examination of the distribution of runoff over continents of the model reveals that the watersheds of many important rivers of the world are correctly positioned in the simulation. In general, the quality of the simulation tends to deteriorate in the neighborhood of major mountain ranges. Furthermore, the rate of precipitation and that of runoff over continental regions in the model tropics is much larger than estimates of the actual rates of these quantities. Nevertheless, this study demonstrates that the model is capable of reproducing many of the basic features of the seasonal variation of hydrology and climate on a global scale

ISSN:0148-0227    

DOI:10.1029/JC080i012p01617

年代:1975

数据来源: WILEY

摘要:

Estimates have been made of the annual emissions of HCl, HF, and SO2to the troposphere and stratosphere from volcanic eruptions. The estimated annual emission rates to the troposphere are 7.5×105, 3.8×104, and 7.5×106metric tons, respectively, and those to the stratosphere are 2.8×104, 1.4×103, and 2.8×105, respectively. The results demonstrate that anthropogenic chlorofluorocarbons have the potential to play a much greater role in stratospheric chemistry than the halides from volcanic eruptions do except possibly for short periods following very intense volcanic act

ISSN:0148-0227    

DOI:10.1029/JC080i012p01650

年代:1975

数据来源: WILEY

摘要:

Six tropospheric profiles of the N2O concentrations over the United States are reported. The mean profile indicates a possible weak decrease of N2O with altitude. The mean value of all data above 4‐km altitude is 0.241 ± 0.006 ppm by volu

ISSN:0148-0227    

DOI:10.1029/JC080i012p01653

年代:1975

数据来源: WILEY

摘要:

The results of our earlier studies of reflection and absorption in various spectral regions are reviewed and then used to provide values of the complex index of refraction of water at 27°C in the spectral range 5000–10 cm−1, corresponding to wavelengths in the range 2 μm to 1 mm. Values ofn,k, and the Lambert absorption coefficient a, which are presented graphically and in tabular form, should prove useful in studies of the scattering of infrared radiation by water droplets in the atmosphere and in studies of radiative heat balance at water sur

ISSN:0148-0227    

DOI:10.1029/JC080i012p01656

年代:1975

数据来源: WILEY

摘要:

Several times during the summer season, infrasound from rockets launched in the early morning at Cape Kennedy in Florida was recorded at Palisades, New York (1505 km to the NNE), beginning 85 min after launch. No other equivalent signals were recorded from summer rocket launchings later in the day, although strong signals are recorded from rockets launched at any time in winter. The strong winter effect is caused by the presence of strong stratospheric westerlies, which provide a good sound channel between the stations. This sound channel disappears in summer, when the stratospheric winds are easterly. The few good summer signals are explained by reflection above 100 km because tidal winds at that level in the early morning cause a favorable sound channel between source and receiver. The lower‐frequency content of summer signals, compared with that of winter signals, is shown to result from attenuation of higher frequencies above 50 k

ISSN:0148-0227    

DOI:10.1029/JC080i012p01662

年代:1975

数据来源: WILEY

摘要:

The general meteorological conditions and precipitation characteristics in the Northeast Brazil dry region during its rainy season from December through April are discussed. It is found that most of the yearly rainfall comes in six to eight episodes from organized weather systems which move from east to west with about the same speed (∼5 m s−1) as the lower tropospheric wind flow. These systems appear not to be of local origin. Rainfall is shown to be inversely correlated with the regional subsidence. An interesting and previously unknown diurnal rainfall variation is found. Orographic influences appear to act to modulate the weather systems and develop upslope and downslope winds. This produces rainfall in the morning over the lowland regions and in the afternoon over the hills and more elevated regions. Extensive comparisons of the rain systems with other tropical regions are made. Other characteristics are discus

ISSN:0148-0227    

DOI:10.1029/JC080i012p01665

年代:1975

数据来源: WILEY

摘要:

Nearly 4 million ship drift reports from 1900 through 1972 have been summarized in squares of 5° latitude × 10° longitude for the oceans of the world and separately in 5° × 5° squares for the North Pacific. The averages for the squares have themselves been averaged to provide mean latitudinal values of the components and their standard deviations. This has been done for each of the four seasons and for the year. The resulting profiles of these values reveal such features as the equatorial countercurrent and show how it changes with season. Profiles of the first differences of the v component reveal the latitudes of up‐welling and down

ISSN:0148-0227    

DOI:10.1029/JC080i012p01679

年代:1975

数据来源: WILEY

摘要:

The average tidal energy budget of Narragansett Bay, a weakly stratified estuary, has been determined from observations of tidal height and current. For average conditions the tidal energy influx to the bay is balanced by the bay's energy sinks, and within the error limits the energy budget balances completely. The average energy inputs to the three bay channels, the West Passage, the East Passage, and the Sakonnet River, are 4.3, 6.4, and 1.1×1013ergs/s, respectively. Tidal energy is dissipated on the bottom of the bay at the average rate of 8.8×1013ergs/s, mostly in a few localized areas of high dissipation. The bay does work on the moon at an average rate of 1.8×1013ergs/s. The energy required for vertical mixing is 0.3×1013ergs/s. Phase adjustment between tidal height and current is suggested as a mechanism contributing to the instantaneous balance of the tidal energy budget over the lunar cy

ISSN:0148-0227    

DOI:10.1029/JC080i012p01683

年代:1975

数据来源: WILEY