Use of radio-controlled miniature aircraft for marine atmosphere sampling     

Frederick R. Hess 《Marine Chemistry》1977,5(3):297-302

The use of Radio-Controlled Miniature aircraft by the Woods Hole Oceanographic Institution for obtaining marine air samples is discussed. The particular requirements for gaseous as well as large-volume particulate sampling are discussed and at-sea tests performed from the R/V “Knorr” are described. Handling and logistics of use as well as aircraft characteristics are discussed.  相似文献   

Distribution of seabirds in the northern Gulf of Mexico in relation to mesoscale features: initial observations   总被引：1，自引：0，他引：1  

Ribic  Christine A.; Davis  Randall; Hess  Nancy; Peake  Dwight 《ICES Journal of Marine Science》1997,54(4):545-551

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A comparative study of atmospheric conductivity at ground level and at one meter above ground     

George A. O'Donnell  Victor F. Hess 《Meteorology and Atmospheric Physics》1951,4(1):351-367

Summary Observations made at various locations, with portable apparatus, from within New York City to one-hundred miles of the city show the following results: (1) The total conductivities at ground level and at one meter above ground are not equal. In general, the one-meter conductivity is greater than the ground during the day, but at night the ground value is the greater. Also, for high values of conductivity the total one-meter conductivity is greater than that at ground level. For lower values the reverse is the case. This might not be true for all locations. (2) The ratios of the polar conductivities of one sign at ground level to the corresponding values at one meter are not constant, and the ratio of the total conductivity at ground level to that at one meter is not constant. (3) These ratios depend upon wind velocities, the amount of pollution in the air, on the nature of the terrain, and upon the time, i. e., day or night.(4) Under normal conditions, conductivity rises to an early morning maximum, the ground maximum rising more sharply that the one-meter, and remains fairly constant during the day but drops inthe late afternoon or early evening reaching a minimum between 20h and 22h. (5) When variation in conductivity takes place under constant turbulence (wind 0–1), the one-meter conductivities change more rapidly than those at the ground (except at the time of maximum), where terrain is level. Local conditions may alter the above (e. g., smoky air rising from lower ground). Also, under all conditions the one-meter conductivity is more variable than ground conductivity. (6) Our findings do not confirm those ofP. J. Nolan [1] andA. R. Hogg [2] that the unipolar (positive) conductivity at ground is almost equal to the total conductivity at one meter above ground.

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Zusammenfassung Unsere Beobachtungen über die atmosphärische Leitfähigkeit in Bodenhöhe und einen Meter darüber, die mit einem Gerdienschen Aspirator mit Wulf-Elektrometer in der näheren und weiteren Umgebung der Stadt New York (bis 160 km Entfernung) ausgeführt wurden, führten zu folgenden Resultaten: 1. Die totale Leitfähigkeit der Luft nahe dem Erdboden und in 1 m Höhe ist nicht gleich. Im allgemeinen ist bei höheren Werten die Leitfähigkeit in 1 m Höhe während der Tagesstunden größer als am Erdboden, während es in der Nacht umgekehrt ist. Bei niedrigen Werten der Leitfähigkeit kehrt sich dieses Verhältnis um; doch trifft dies möglicherweise nicht für alle Orte zu. 2. Das Verhältnis der polaren Leitfähigkeit je eines Vorzeichens am Boden zu der entsprechenden in 1 m Höhe ist nicht konstant; dasselbe gilt auch für die Gesamtleitfähigkeit. 3. Die numerischen Werte dieser Verhältniszahlen hängen von der Windgeschwindigkeit (Turbulenz), dem Gehalt der Luft an Verunreinigungen, den Terrainverhältnissen und der Tageszeit ab. 4. Normalerweise erreicht die Leitfähigkeit ein Maximum in den frühen Morgenstunden; dabei erfolgt der Anstieg zum Maximum am Boden steiler als in 1 m Höhe. Während des Tages bleibt die Leitfähigkeit ziemlich konstant, fällt dagegen am späten Nachmittag und erreicht ihr Minimum zwischen 20 Uhr und 22 Uhr. 5. Wenn bei konstanten Turbulenzbedingungen (Windstärke 0–1) eine Änderung der Leitfähigkeit erfolgt, so ändert sich die Leitfähigkeit über ebenem Terrain in 1 m Höhe stärker als am Boden (außer zur Zeit des Hauptmaximums). Lokale Verhältnisse (wie z. B. Rauch) können dies ändern. In allen Fällen ist die Leitfähigkeit in 1 m Höhe stärker veränderlich als am Boden. 6. Unsere Ergebnisse bieten keine Bestätigung der Resultate vonP. J. Nolan [1] undA. R. Hogg [2], wonach die positive Leitfähigkeit am Boden fast ebenso groß ist wie die gesamte Leitfähigkeit in 1 m Höhe über dem Boden.

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Résumé Nos mesures de la conductibilité atmosphérique au niveau du sol et à un mètre de hauteur effectuées avec un aspirateur de Gerdien et un électromètre de Wulf aux environs immédiats et lointains de New-York (jusqu'à 160 km de distance) ont conduit aux résultats suivants. 1. La conductibilite totale au niveau du sol n'est pas la même qu'à un mètre. En général pour les valeurs élevées la conductibilité est plus forte à un mètre qu'au sol pendant le jour; l'inverse a lieu la nuit. Pour les valeurs faibles le phénomène s'inverse, mais ce n'est pas nécessairement le cas partout. 2. Le rapport de la conductibilité polaire de chaque signe au sol à celle qui lui correspond à un mètre n'est pas constant; il en est de même pour la conductibilité totale. 3. La valeur numérique de ces rapports dépend de la vitesse du vent, de la teneur de l'air en impuretés, de la configuration du terrain et du moment de la journée.4. La conductibilité atteint normalement un maximum dans les premières heures du jour; l'accroissement est alors plus rapide au sol qu'à un mètre. Pendant la journée la conductibilité reste sensiblement constante, décroît cependant en fin d'après-midi et atteint son minimum entre 20 et 22 heures. 5. Si par turbulence constante (vitesse du vent 0 à 1) il se produit une variation de la conductibilité, celle-ci varie plus fortement à un mètre qu'au niveau du sol en terrain plat (sauf à l'époque du maximum principal). Les conditions locales, comme la fumée par exemple, peuvent ici apporter des modifications. Dans tous les cas la conductibilité varie davantage à un mètre que sur le sol. 6. Nos résultats ne confirment pas ceux deP. J. Nolan [1] et deA. R. Hogg [2] selon lesquels la conductibilité positive au niveau du sol serait presque aussi grande que la conductibilité totale à la hauteur d'un mètre.

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With 12 Figures.  相似文献   

The last lavas erupted during the main phase of the Siberian flood volcanic province: results from experimental petrology     

Linda T. Elkins-Tanton  David S. Draper  Carl B. Agee  Jessica Jewell  Andrew Thorpe  P. C. Hess 《Contributions to Mineralogy and Petrology》2007,153(2):191-209

The final lavas of the Siberian flood basalts are a ∼1,000 m thick section of meimechites, high-alkali, high-titanium, hydrous lavas that contrast sharply with the tholeiites that precede them. This paper presents a phase equilibrium study indicating that a candidate primary meimechite magma with 1 wt% water originated at ∼5.5 GPa and 1,700°C, both hotter and shallower than other estimates for melting beneath continental lithosphere. The experiments also suggest that a higher volatile content was involved in meimechite source genesis. Both the absence of orthopyroxene in any experiment and the close field association with carbonatites suggest that the meimechite source region may have been metasomatized with a CO₂-rich fluid. A small additional quantity of CO₂ and water would move magma origination to ∼1,550–1,600°C.  相似文献   

An ozone depletion event in the sub-arctic surface layer over Hudson Bay,Canada     

B. A. Ridley  T. Zeng  Y. Wang  E. L. Atlas  E. V. Browell  P. G. Hess  J. J. Orlando  K. Chance  A. Richter 《Journal of Atmospheric Chemistry》2007,57(3):255-280

During the Tropospheric Ozone Production about the Spring Equinox (TOPSE) program, aircraft flights during April 7–11, 2000 revealed a large area air mass capped below ∼500 m altitude over Hudson Bay, Canada in which ozone was reduced from normal levels of 30–40 ppbv to as low as 0.5 ppbv. From some of the in-situ aircraft measurements, back-trajectory calculations, the tropospheric column of BrO derived from GOME satellite measurements, and results from a regional model, we conclude that the event did not originate from triggering of reactive halogen release in the sub-Arctic region of Hudson Bay but resulted from such an event occurring at higher latitudes over the islands of the northern Canada Archipelago and nearby Arctic Ocean with subsequent transport over a distance of 1,000–1,500 km to Hudson Bay. BrO _x remained active during this transport despite considerable changes in the conditions of the underlying surface suggesting that chemical recycling during transport dominated any local halogen input from the surface. If all of the tropospheric column density of BrO is distributed uniformly within the surface layer, then the mixing ratio of BrO derived from the satellite measurements is at least a factor of 2–3 larger than derived indirectly from in situ aircraft measurements of the NO/NO₂ ratio.  相似文献   

Implications of liquid-liquid distribution coefficients to mineral-liquid partitioning   总被引：1，自引：0，他引：1  

F.J. Ryerson  P.C. Hess 《Geochimica et cosmochimica acta》1978,42(6):921-932

The effect of silicate liquid structure upon mineral-liquid partitioning has been investigated by determining element partitioning data for coexisting immiscible granitic and ferrobasaltic magmas. The resulting elemental distribution patterns may be interpreted in terms of the relative states of polymerization of the coexisting magmas. Highly charged cations (REE, Ti, Fe, Mn, etc.) are enriched in the ferrobasaltic melt. The ferrobasaltic melt is relatively depolymerized due to its low $\text{Si}\text{O}$ ratio. This allows highly charged cations to obtain stable coordination polyhedra of oxygen within the ferrobasaltic melt. The granitic melt is a highly polymerized network structure in which Al can occupy tetrahedral sites in copolymerization with Si. The substitution of Al⁺³ for Si⁺⁴ produces a local charge imbalance in the granitic melt which is satisfied by a coupled substitution of alkalis, thus explaining the enrichment of low charge density cations, the alkalis, in the granitic melt. P₂O₅ increases the width of the solvus and, therefore, the values of the distribution coefficients of the trace elements. This effect is attributed to complexing of metal cations with PO₄^?3 groups in the ferrobasaltic melt.The values of ferrobasalt-granite liquid distribution coefficients are reflected in distribution coefficients for a mineral and melts of different compositions. The mineral-liquid distribution coefficient for a highly charged cation is greater for a mineral coexisting with a highly polymerized melt (granite) than it is for that same mineral and a depolymerized melt (ferrobasalt). The opposite is true for low charge density cations. Mineralliquid and liquid-liquid distribution coefficients determined for the REE's indicate that fractionated REE patterns are due to mineral selectivity and not the state of polymerization of the melt.  相似文献   

On the relation between surface wind and pressure gradient,especially in lower latitudes     

R. H. Clarke  G. D. Hess 《Boundary-Layer Meteorology》1975,9(3):325-339

Observations show that the angle between surface wind and isobar increases equatorward in low latitudes while the ratio of surface to geostrophic wind speed decreases. With the use of Southern Hemisphere winter fields of surface pressure and temperature over the oceans, and Rossby number similarity theory (including the effects of baroclinicity) in several different forms, the expected latitudinal variation of the angle and ratio has been computed. A check has also been made of mean ATEX and BOMEX data. It appear that the variations with latitude are probably mainly due to baroclinicity. With this factor taken into account, similarity theory fairly adequately explains the observations.A recently proposed form of similarity theory based on the assumption of very strong momentum mixing in the boundary layer was also tested. It predicts the equatorward increase of the angle, even without baroclinicity. Quantitatively the results of the test are not in good agreement with observation. However, the strong convective mixing assumed in the theory does not generally occur over the oceans, and this test must be regarded as inconclusive.  相似文献   

Die Kristallstruktur von Warikahnit,Zn3[(H2O)2|(AsO4)2]     

Dr. H. Riffel  Priv.-Doz. Dr. P. Keller  Prof. Dr. H. Hess 《Mineralogy and Petrology》1980,27(3):187-199

Zusammenfassung Die Kristallstruktur des neuen Minerals Warikahnit, Zn₃[(H₂O)₂|(AsO₄)₂], wurde mit Diffraktometerdaten bestimmt und bis zuR=0,038 für 3428 unabhängige Reflexe verfeinert.Warikahnit ist triklin, , mita=6,710(1),b=8,989(2),c=14,533(2) Å, =105,59(1), =93,44(1), =108,68(1)°,Z=4.Die Kristallstruktur des Warikahnits enthält sechs unterschiedliche Koordinationspolyeder des Zinks mit den Koordinationszahlen 6, 5 und 4 und mit fünf verschiedenen Ligandenkombinationen. Die Wasserstoffbrückenbindungen werden mit Hilfe der Ladungsbilanz und des IR-Spektrums diskutiert.

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The crystal structure of warikahnite, Zn₃[(H₂O)₂|(AsO₄)₂]

Summary The crystal structure of the new mineral warikahnite, Zn₃[(H₂O)₂|(AsO₄)₂], was determined from diffractometer data and refined toR=0,038 for 3428 observed independent reflections.Warikahnit is triclinic, , witha=6.710(1),b=8.989(2),c=14.533(2) Å, =105.59(1), =93.44(1), =108.68(1)°,Z=4.The crystal structure of warikahnite contains 6 different coordination polyhedra of zinc with the coordination numbers 6,5 and 4 and with 5 different combinations of ligand. The hydrogen bonds are discussed on the basis of charge balance and IR spectra.

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Mit 3 Abbildungen  相似文献   

The role of P₂O₅ in silicate melts     

F.J. Ryerson  P.C. Hess 《Geochimica et cosmochimica acta》1980,44(4):611-624

Phase equilibria data in the systems SiO₂-P₂O₅, P₂O₅-M_xO_y, and P₂O₅-M_xO_y-SiO₂ are employed in conjunction with Chromatographic and spectral data to investigate the role of P₂O₅ in silicate melts. Such data indicate that the behavior of P₂O₅ is complex. P₂O₅ depolymerizes pure SiO₂ melts by entering the network as a four-fold coordinated cation, but polymerizes melts in which an additional metal cation other than silicon is present. The effect of this polymerization is apparent in the widening of the granite-ferrobasalt two-liquid solvus. In this complex system P₂O₅ acts to increase phase separation by further enrichment of the high charge density cations Ti, Fe, Mg, Mn, Ca, in the ferrobasaltic liquid. P₂O₅ also produces an increase in the ferrobasalt-granite REE liquid distribution coefficients. These distribution coefficients are close to 4 in P₂O₅-free melts, but close to 15 in P₂O₅-bearing melts.The dual behavior of P₂O₅ is explained in a model which requires complexing of phosphate anions (analogous to silicate anions) and metal cations in the melt. This interaction destroys Si-O-M-O-Si bonds polymerizing the melt. The higher concentration of Si-O-M-O-Si bond complexes in immiscible ferrobasaltic liquids relative to their conjugate immiscible granite liquids explains the partitioning of P₂O₅ into the ferrobasaltic liquid.  相似文献   

Ab initio valence force field calculations for quartz     

Paul F. McMillan  Anthony C. Hess 《Physics and Chemistry of Minerals》1990,17(2):97-107

We have derived valence force constants for the tetrahedral SiO₄ unit and the inter-tetrahedral SiOSi linkage from previous ab initio molecular orbital calculations on H₄SiO₄ and H₆Si₂O₇ using a split-valence polarized Gaussian basis set (6-31G^*), and used these to calculate the infrared and Raman active vibrational modes of α-quartz. The calculation gives frequencies approximately 15% greater than experiment, as expected from harmonic force constants obtained at this level of Hartree-Fock theory, but the calculation gives the correct distribution of modes within each frequency range. Calculated 28–30 Si and 16–18 O isotope shifts and pressure shifts to 6 GPa are also in reasonable agreement with experiment. We have also used our ab initio force field to calculate the vibrational spectrum for β-quartz. The results suggest either that inclusion of a torsional force constant is important for determining the stability of this high temperature polymorph, or that the β-quartz has a disordered structure with lower symmetry (P6₂) domains, as suggested by earlier diffraction studies.  相似文献