摘要:

A practical mathematical model for representing water particle motion generated by air‐sea interaction under storm conditions is proposed. The equations of motion of a rotational fluid are discussed in conjunction with observed characteristics in order to obtain realistic approximations. Previously derived solutions for a single wave frequency are summarized and extended to a continuous spectrum. The solution proposed is valid for conditions prevalent on the far shore zone of the continental shel

ISSN:0148-0227    

DOI:10.1029/JC081i003p00363

年代:1976

数据来源: WILEY

摘要:

During 1974 at least 7 one‐dimensional models of vertical eddy transport and photochemistry had been used to predict the reduction of ozone by nitrogen oxides from supersonic transports. Chang (1974) has shown that these predictions are sensitive to the assumed values for the vertical eddy diffusion coefficientKz. In this article an effort is made to calibrate the one‐dimensionalKzfunctions against quantitative data for the dissipation of excess carbon 14 from the stratosphere during the period 1963–1970. The data for excess carbon 14, following the nuclear bomb test series of 1961–1962, were published in 1971 and 1972, and these data were not used to derive the variousKzfunctions. Tables of data are presented in a form that may be useful to others in calibrating two‐ and three‐dimensional models of stratospheric motion. In checking the one‐dimensional models the direct observations by balloons at 30°N are primarily used. Also, these data are interpreted as a special hemispherical average (averaging along lines parallel to a standard sloping tropopause). The carbon 14 data and strontium 90 data differ in many important respects, and it is judged that the carbon 14 data give the better estimate of air motion in the stratosphere. The sevenKzmodels give predictions that strongly differ from one model to another. The models that give a fairly realistic prediction of carbon 14 distribution and persistence are those with minimumKzbetween 15 and 20 km and with increasingKzfrom 20 to 50 km. Models with these features, as recalculated by Chang (1974), agree with each other as to ozone reduction by artificial nitrogen oxides from supersonic transports (SSTs). These models are used to predict the ozone reduction by SST's according to Grobecker's (1974) upper bound projection out to the year 2025. Very large reductions of global ozone are indicated, more than

ISSN:0148-0227    

DOI:10.1029/JC081i003p00368

年代:1976

数据来源: WILEY

摘要:

In a suite of 12 Cretaceous shales of the northern Great Plains of the United States the whole‐quartz oxygen isotopic delta values (δ18O) decrease from 22 to 15‰ from the central marine basin, where chert and biogenic silica are higher, to the westward shore near volcanic rock sources. The δ18O for the 1‐ to 10‐μm size fractions showed the same trend. The δ18O values are still lower (12–14‰) for two nonmarine Tertiary Rocky Mountain outwash sediments of NB and CO. Thus the oxygen isotope ratios reflect the provenance of the quartz. The δ18O values of whole quartz and/or of the 1‐ to 10‐μm size (the size commonly wind‐transported over long distances) isolated from 36 Mesozoic and Paleozoic shales of the midcontinental United States range from 15.1 to 23.9‰. The mean δ18O values for 31 whole quartz (19.1±1.4‰; ±2 σ) and the 1‐ to 10‐μm quartz fractions from 30 shales (20.7±1.20‰) differed by only 1.6‰ (a maximum of 3.1‰). The δ18O values of 1‐ to 10‐μm quartz from the shales did not vary systematically with age through the Paleozoic and Mesozoic eras (Cambrian, 21–22‰; Ordovician, 18–22‰; Devonian, 18–22‰; Mississippian‐Permian, 18–24‰; and Jurassic‐Cretaceous, 17–l24‰). The variation for each period may reflect differences in provenance, such as distance from igneous sources versus localities of chert quartz deposition. The δ18O value of quartz from shales is intermediate between those values which characterize quartz of high‐ and low‐temperature rock provenances; thus it is suggested that shales are reservoirs of quartz of mixed provenance. The range of δ18O values for the 1‐ to 10‐μm (aerosol size) quartz of the shales and the abundance of the shales suggest that soils derived from shale bedrocks (via glacial

ISSN:0148-0227    

DOI:10.1029/JC081i003p00381

年代:1976

数据来源: WILEY

摘要:

The method presented by Hewitt and Martin (1973) for calculating residence times is elaborated and extended. A simple modification of the procedure allows the calculation of transfer times (a transfer time is the average time it takes a particle at a given place to move to a certain other place). Exact results relevant to the use of the method are discussed. The method is used to calculate times for transfer from the northern to the southern stratosphere.

ISSN:0148-0227    

DOI:10.1029/JC081i003p00387

年代:1976

数据来源: WILEY

摘要:

In skies with scattered predominantly cumulus cloud cover the global irradiance is very close to that which would occur for a clear sky due to scattering and reflection from the sides of clouds. Several examples of this effect are shown. Limited data on the insolation indicate that the reduction in insolation due to scattered cumulus type clouds cannot be represented adequately by the traditional linear relationship (Angström, 1924) for cloud covers less than 0.5

ISSN:0148-0227    

DOI:10.1029/JC081i003p00395

年代:1976

数据来源: WILEY

摘要:

Results of observations of CO2concentration [CO2] and flux in an area of typical agricultural land use in the east central Great Plains of North America (Mead, Nebraska) are reported. The observations were made at sufficient heights to represent an integration of CO2fixation and release due to all types of land use in the region (pasture, alfalfa, annual crops). Minimum daytime [CO2] ranges from about 295–300 ppm in late July to early August (the time of apparent maximum photosynthetic activity) to 328–332 ppm in winter. The shape of the annual CO2concentration cycle at Mead is described and compared with those for Mauna Loa, Hawaii, and Barrow, Alaska. Peak daytime flux of CO2(in g×10−7cm−2s−1) from the atmosphere to the ground varied from about 0.5 in early June to 1.5–2.0 in late July to early August and 0.5 in late September. The net daily CO2flux (in grams per square meter), calculated from the downward daytime and upward nocturnal fluxes, is about 10–12 in early June, 18–20 in early August (maximum), 6–10 in September, and 1

ISSN:0148-0227    

DOI:10.1029/JC081i003p00399

年代:1976

数据来源: WILEY

摘要:

An evaluation of 30 pairs of high‐altitude inflatable falling spheres and independent thermistor soundings with a mean rocket launch time separation of 27 min shows average temperature differences within 6°C at 32–70 km except for an average difference of 10° at 68 km, near Mach 1 in the sphere descent curve. The mean difference is exhibited as a negative bias (sphere temperature colder) for which various explanations are considered. The rms temperature differences are greatest near 50 km (7°C) and 68 km (11°C). From 70 to approximately 87.5 km, confidence in the reliability of the sphere temperature soundings is based on the ‘repeatability’ of pairs of sphere soundings taken within 20 min, temperature differences generally being less than 10°C. Illustrations of large atmospheric variations measured by the sphere soundings are given, along with verification from independent

ISSN:0148-0227    

DOI:10.1029/JC081i003p00406

年代:1976

数据来源: WILEY

摘要:

We present a time‐dependent photochemical model of tropospheric ozone. In accordance with our previous calculations (Chameides and Walker, 1973) we treat ozone as an active chemical constituent with a local abundance that is determined by photochemical processes rather than by transport processes. The local abundance of odd nitrogen is shown to play a major role in determining the intensity of photochemical production and destruction of ozone, a large local abundance of NOx(= NO + NO2) leading to large diurnal ozone variations. The photochemical model is shown to reproduce the diurnal variations of ozone and nitrogen dioxide observed near the ground at Research Triangle Park in North Carolin

ISSN:0148-0227    

DOI:10.1029/JC081i003p00413

年代:1976

数据来源: WILEY

摘要:

Ozone in the lower troposphere has traditionally been attributed to two different sources, injection from the stratosphere and local or regional photochemical synthesis. Recently,Chameides and Walker[1973, 1976] proposed that photochemical synthesis of ozone (via a methane oxidation chemistry) is significant in areas remote from obvious pollution. They characterize as their ‘basic argument that photochemical sources of ozone in the troposphere are larger than the source provided by transport from the stratosphere’ [Chameides and Walker, 1974]. This photochemical hypothesis appears welcome amid several reports of repeated but intermittent high concentrations of ozone at surface measuring stations in supposedly unpolluted areas [A ttmannspacher and Hartmannsgruber, 1973;Wallis et al., 1975] (also, data of L. A. Ripperton and J. J. B. Worth as summarized byCorn et al. [197

ISSN:0148-0227    

DOI:10.1029/JC081i003p00421

年代:1976

数据来源: WILEY

ISSN:0148-0227    

DOI:10.1029/JC081i003p00424

年代:1976

数据来源: WILEY