Evidence for high-altitude haze thickening on the dark side of Venus from 10-micron heterodyne spectroscopy of CO₂     

D. Deming  F. Espenak  D. Jennings  T. Kostiuk  M. Mumma 《Icarus》1982,49(1):35-48

The 10.86-μm P(44) and 10.33-μm R(8) lines of ¹²C¹⁶O₂ were observed on Venus with an infrared heterodyne spectrometer. The spectral resolution equals the Doppler half-width and the line profiles are fully resolved. The P(44) line was observed in June 1979 on the day side of the planet. The P(44) line core appears in absorption; the nonthermal core emission, which is present at low J values, is negligible at J = 44. Modeling of the line profile indicates that a discrete, optically thick, cloud deck occurs at 45 mbar pressure, in essential agreement with current understanding of the Venusian cloud structure. The 10.33-μm R(8) line was observed in April 1980 at a variety of positions on the day side, and at a single position on the night side. The strong nonthermal core emission which appears on the day side for this line is not present on the night side, where the line core appears in absorption. This behavior is consistent with a solar radiative pump as an excitation mechanism for the nonthermal emission. Modeling of the R(8) night-side profile indicates that substantial high-altitude haze occurs above the cloud tops, in the region from 15 to 35 mbar pressure. Comparing the modeling for the R(8) line to the P(44) line we find that the variation in the mass of the high-altitude haze was greater than a factor of 2.  相似文献   

The charging of water drops falling and colliding in an electric field     

S. G. Jennings  Dr. J. Latham 《Meteorology and Atmospheric Physics》1972,21(2-3):299-306

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Weathering phases recorded by gnammas developed since last glaciation at Serra da Estrela, Portugal     

David Domínguez-Villar  Laura Razola  Rosa M. Carrasco  Carrie E. Jennings  Javier Pedraza 《Quaternary Research》2009,72(2):218-228

The morphometrical analysis of gnammas (weathering pits) in granite landscapes has been used to establish the relative chronology of recent erosive surfaces and to provide the weathering history in a region. To test the validity of gnammas as relative chronometer indicators, and the reliability of the obtained weathering record, two sites have been studied in Serra da Estrela, Portugal. The first site is within the limits of the glacier that existed in these mountains during the last glaciation, whereas the second site is located in an unglaciated sector of the mountains, which preserves a longer record of weathering in the bedrock surface. The number of gnamma weathering phases recorded in the latter site (8) is larger than those from the former (6). Correlation between both measurement stations based on morphometrical criteria is excellent for the younger six weathering phases (1 to 6). Consequently, the parameter used for relative chronology (δ-value) has been verified to be age dependent, although absolute values are modulated by microclimate due to altitude variations. The weathering record was essentially duplicated once the surfaces at both sites were exposed, demonstrating the reliability of gnamma evolution as a post-glacial environmental indicator for the region.  相似文献   

Structure and texture of a gravelly barrier island in the Fitzroy estuary,Western Australia,and the role of mangroves in the shore dynamics     

J.N. Jennings  R.J. Coventry 《Marine Geology》1973,15(3):145-167

In the stratification of the most coarse-textured barrier island of a system of sand and gravel barrier spits and islands on Point Torment peninsula, King Sound, W.A., foreslope beds due to swash-backwash on the beach face are unimportant. The main units are steeply-dipping backslope beds and topslope beds of gentle, chiefly landward inclination. Their bimodal sediments are poorly sorted for wave-built features. A very coarse mode usually at ?1.5 to ?2 ?i; belongs to a population of well-rounded but platy, impure limestone, of local but unlocated source, whereas the fine mode, almost invariably 1.00 to 1.25 ?i;, represents a population of quartz sand fed from low and sub-tidal estuarine shoals. The two populations are thought to derive from the surface creep and saltation cloud components of “traction carpets”. Swash of intermediate energy waves forms the topslope beds through percolation. Washover by waves of translation generated by occasional hurricanes erodes the top of the feature and deposits the backslope beds on the rear face in standing water at abnormally high levels through storm set-up. In both, unidirectional currents produce sediments with certain resemblances to fluvial “traction clog” deposits.Dated by underlying mangrove wood of 1200 B.P. in front and of 500 B.P. in the rear, this barrier probably retreated through mangrove swamp in the manner of some presently active members of the barrier system. The seaward mangrove swamps neither protect the embankments behind nor suffer seriously from the waves rolling the latter landward.  相似文献   

Interaction between warm Atlantic‐sourced waters and the East Greenland Current in northern Denmark Strait (68°N) during the last 10 600 cal a BP          下载免费PDF全文

Kerstin Perner  Anne E. Jennings  Matthias Moros  John T. Andrews  Lukas Wacker 《第四纪科学杂志》2016,31(5):472-483

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Comments on the gamma-ray burst logN>S) — LogS point of Beurleet al.     

Mark C. Jennings 《Astrophysics and Space Science》1982,88(2):429-432

The isotropic cumulative burst rate of 7030 _–6000 ⁺¹⁰⁰⁰⁰ yr^–1 at a fluence ofS=8.47×10^–9 erg^–1 cm^–2 determined by Beurleet al. from their observation of two gamma-ray bursts is shown to be statistically improbable. The difficulty arises from their assumption that the power law cumulative distribution function index equals one. Their observations are rediscussed and an upper limit ofN(>8.47×10^–9 erg cm^–2)<5400 yr^–1 is proposed.  相似文献   

Limb observations of the 12.32-micron Mg I emission line during the 1994 annular eclipse     

Deming  Drake  Jennings  Donald E.  McCabe  George  Moran  Thomas  Loewenstein  Robert 《Solar physics》1998,182(2):283-291

We determined the limb profile of the extremely Zeeman-sensitive emission line of Mg i at 12.32 m (811.58 cm–1) during the May 1994 annular eclipse, using the 3.5-m ARC telescope at the Apache Point site on Sacramento Peak, New Mexico. Spectra were recorded at 0.1 cm–1 spectral resolution and 1 s time resolution using a cryogenic grating spectrometer. The time derivatives of the observed line energy and continuum intensity were used to infer high-resolution profiles of the solar limb. Data were obtained at second contact only, since clouds prevented observations at third contact. We find that the emission line energy peaks very close to the 12 m continuum limb. This agrees with our result from the 1991 total eclipse over Mauna Kea, and also with non-LTE radiative transfer theory for this line, which predicts an upper-photospheric origin. However, in 1991, line emission remained observable as high as 2000 km above the continuum limb, whereas the 1994 data show observable emission to only 500 km. This difference greatly exceeds any applicable errors, or sensitivity differences in either data set, and must be attributed to spatial and/or temporal inhomogeneities in the solar limb emission of this line. We discuss possible causes of these inhomogeneities, and implications for observations at far-IR and submillimeter wavelengths.  相似文献   

Doline Morphometry as a Morphogenetic Tool: New Zealand Examples     

J. N. Jennings 《New Zealand geographer》1975,31(1):6-28

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Predicting the effects of area closures and fishing effort restrictions on the production, biomass, and species richness of benthic invertebrate communities   总被引：3，自引：0，他引：3  

Hiddink  J.G.; Hutton  T.; Jennings  S.; Kaiser  M.J. 《ICES Journal of Marine Science》2006,63(5):822-830

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Do climate and fishing influence size-based indicators of Celtic Sea fish community structure?   总被引：7，自引：1，他引：7  

Blanchard  Julia L.; Dulvy  Nicholas K.; Jennings  Simon; Ellis  James R.; Pinnegar  John K.; Tidd  Alex; Kell  Laurence T. 《ICES Journal of Marine Science》2005,62(3):405-411

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