Tropospheric lapse rate and its relation to surface temperature from reanalysis data   总被引：2，自引：0，他引：2  

I. I. Mokhov  M. G. Akperov 《Izvestiya Atmospheric and Oceanic Physics》2006,42(4):430-438

Estimates of the tropospheric lapse rate γ and analysis of its relation to the surface temperature T _s in the annual cycle and interannual variability have been made using the global monthly mean data of the NCEP/NCAR reanalysis (1948–2001). The tropospheric lapse rate γ is about 6.1 K/km in the Northern Hemisphere (NH) as a whole and over the ocean and about 6.2 K/km over the continents. The value of γ decreases from 6.5 K/km at low latitudes to 4.5 K/km at polar latitudes. The values of dγ/dT _s, the parameter of sensitivity of γ to the variation of T _s for the NH in the interannual variability, are found to be about 0.04 km^?1 (0.041 km^?1 for the NH as a whole, 0.042 km^?1 over the ocean, and 0.038 km^?1 over the continents). This corresponds to an increase in γ of approximately 0.7% when the surface temperature of the NH is increased by 1 K. Estimates of dγ/dT _s vary from about 0.05 km^?1 in the subtropics to 0.10 km^?1 at polar latitudes. When dγ/dT _s is positive, the surface and tropospheric warming means a temperature decrease above a certain critical level H _cr. The height of the level H _cr with constant temperature, which is defined by the inverse value (dγ/dT _s)^?1, is about 25 km for the NH as a whole, i.e., above the tropopause. In the subtropics, H _cr is about 20 km. At polar latitudes, H _cr decreases to about 10 km. Positive values of dγ/dT _s characterize a positive climatic feedback through the lapse rate and indicate a general decrease in the static stability of the troposphere during global warming. Along with a general tendency of γ to increase with rising T _s, there are regional regimes with the opposite tendency, mainly over the ocean. The negative correlation of γ with T _s is found over the oceanic tropics and midlatitudes, in particular, over the oceanic belt around Antarctica.  相似文献   

Verification of first annulus formation in the illicia and otoliths of white anglerfish, Lophius piscatorius using otolith microstructure     

Wright  P. J.; Woodroffe  D. A.; Gibb  F. M.; Gordon  J. D. M. 《ICES Journal of Marine Science》2002,59(3):587-593

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Species, tissue and gender-related organochlorine bioaccumulation in white-sided dolphins, pilot whales and their common prey in the northwest Atlantic   总被引：5，自引：0，他引：5  

Weisbrod AV  Shea D  Moore MJ  Stegeman JJ 《Marine environmental research》2001,51(1):29-50

Organochlorine concentrations were measured in white-sided dolphins, pilot whales, and their prey from the Gulf of Maine and used to identify species, tissue, and gender differences, and trophic transfer trends, in bioaccumulation. Polychlorinated biphenyl concentrations ([PCB]) in dolphin blubber (13 +/- 7.1 micrograms/g fresh wt.) were twice those in pilot whales, but pesticide concentrations (20 +/- 13 micrograms/g fresh) were similar between species. 4,4'-DDE, trans-non-achlor, Cl6(153) and Cl6(138) concentrations were highest. Skin tissues had more recalcitrant organochlorines than the internal organs. Male dolphins bioaccumulated higher concentrations of nonmetabolizable PCBs and hexachlorocyclohexane (HCH) isomers, whereas pilot whales had no gender-related differences in bioaccumulation. Pilot whales, mackerel, and herring had proportionately higher concentrations of DDTs, whereas [PCB] were higher in dolphins and squid. Although these odontocetes feed at the same trophic level and store a similar suite of contaminants, dolphins bioaccumulated higher and potentially hazardous 4,4'-DDE and PCB concentrations from food in their more geographically restricted range.  相似文献   

The Spatial Distribution of Caprellidea (Crustacea: Amphipoda): A Stress Bioindicator in Ceuta (North Africa, Gibraltar Area)   总被引：4，自引：0，他引：4  

José M. Guerra-García  & José C. García-Gómez 《Marine Ecology》2001,22(4):357-367

Abstract. The caprellid (Crustacea: Amphipoda) community associated with the alga Cystoseira usneoides (L.) Roberts 1967 was studied on a spatial scale in relation to the influence of environmental factors on the coast of Ceuta (North Africa) using multivariate analyses. Twenty-two stations were sampled and five environmental factors were tested (hydrodynamics, silting, suspended organic matter, organic matter in silt and suspended solids). The spatial distribution of the caprellid community reflected the physico-chemical conditions of the coast. Phtisica marina Slabber 1769 was the only species present at the stations of the harbour of Ceuta, characterised by the lowest values of hydrodynamics and the highest values of silting, suspended organic matter and suspended solids. The most exposed stations (high hydrodynamics and low values of silting, dissolved organic matter and suspension solids) were mainly dominated by Caprella danilevskii Czerniavskii 1868 and C. penantis Leach 1814. These two species have developed a "parallel" posture that enables them to attach strongly to the substratum and thus inhabit areas subjected to heavy exposure or strong currents. Caprella acanthifera Leach 1814 and Pseudoprotella phasma (Montagu 1804) preferred stations characterised by moderate values of silting and suspended solids, such as those located in the coastal areas in front of the city of Ceuta, but these species were not found at the most stressed harbour stations.  相似文献   

The effect of temperature on growth of Atlantic cod (Gadus morhua L.)     

Brander  K. M. 《ICES Journal of Marine Science》1995,52(1):1-10

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The mixing efficiency and the processes of restratification in a stably stratified medium     

V. S. Maderich  O. M. Konovalov  S. I. Konstantinov 《Physical Oceanography》1994,5(1):21-26

The mechanism of the effect of a collapsing turbulent eddy on diapycnal transport in a stably stratified fluid is considered. It is shown that at small Richardson turbulent numbersRi ₀ the mixing efficiency increases asRi ₀, and at large numbers it decreases in proportion toRi ₀ ^–1/2 .Translated by Mikhail M. Trufanov. UDK 551.465.15.  相似文献   

Analysis of correlations between time series with the use of the phase spectrum     

M. I. Fortus 《Izvestiya Atmospheric and Oceanic Physics》2007,43(5):555-568

In connection with the problem of revealing cause-effect relations among different climatic characteristics, methods for determining the dependence between time series on the basis of selected auto-and cross-covariance functions and periodograms expressed in terms of the Fourier coefficients of the initial series are discussed. Real time series do not always satisfy the conditions of statistical stationarity, so that their analysis requires a combination of statistical and deterministic approaches. The possibility of using the above numerical characteristics in relation to such series is considered. Characteristic features of describing finite segments of time series with the use of their Fourier coefficients is studied in detail. The main emphasis is on the determination of the time shifts (delays) at which the covariance between the series is maximal. The problems that appear during a practical implementation of the periodogram method for shift estimation are discussed. A previously unknown formula that is necessary for further studies and relates the Fourier transform of a selected correlation function to the periodogram of the series is derived.  相似文献   

Water vapor in the atmosphere over the northern Tien Shan     

V. N. Aref’ev  F. V. Kashin  V. K. Semenov  R. M. Akimenko  N. E. Kamenogradskii  N. I. Sizov  V. P. Sinyakov  L. B. Upenek  V. P. Ustinov 《Izvestiya Atmospheric and Oceanic Physics》2006,42(6):739-751

Refined data of systematic measurements of total water vapor in the atmosphere from May 1980 to April 2005 are presented. The data were obtained at the Issyk Kul atmospheric-monitoring station by the method of solar molecular-absorption spectroscopy. Over 25 years, the annual mean water-vapor content in the atmosphere increased by 4.5% at a mean rate of increase of 0.18% per year. However, the water-vapor content decreased in the last five years. The results of statistical processing of experimental data (general statistical characteristics, correlation coefficients, composite oscillations) are described. A refined model is proposed for forecasts of temporal variations in the monthly mean and annual mean water-vapor contents for the coming years. The model includes a linear trend and the sum of oscillations with periods close to the periods of a number of well-known geophysical phenomena. Regression equations are proposed to relate the water-vapor content in the atmospheric column to the surface temperature and absolute humidity.  相似文献   

Bacterial killing by Mytilus hemocyte monolayers as a model for investigating the signaling pathways involved in mussel immune defence     

Canesi L  Scarpato A  Betti M  Ciacci C  Pruzzo C  Gallo G 《Marine environmental research》2002,54(3-5):547-551

The signaling pathways involved in mussel immune defence were investigated utilizing a model of killing of Escherichia coli by Mytilus galloprovincialis hemocytes in a co-culture setting. In particular, the role played by different mitogen activated protein kinases (MAPKs) and by the production of eicosanoids were investigated utilising specific cell permeant, pharmacological enzyme inhibitors. Hemocyte pretreatment with the p38 MAPK inhibitor SB203580 significantly reduced bacterial killing, whereas PD98059 (an inhibitor of ERK--extracellularly regulated kinase--MAPK activation) had no significant effect. Wortmannin also inhibited bacterial killing, indicating a crucial role for PI3-kinase activation in the immune response. Killing of E. coli was also reduced by inhibitors of both PLA2 and cyclooxygenase activities, indicating that eicosanoid production is involved in mediating the response to bacterial challenge. The results demonstrate that bacterial killing by mussel hemocytes is particularly sensitive to inhibitors of the key steps involved in the transduction of bacterial signals into the host cell. Moreover, these data indicate that the hemocyte bactericidal activity can be suitably utilized not only for identifying the signaling pathways involved in the response to bacterial infection, but also as a potential investigative-toxicology model to test drugs and contaminants for their effect on the overall mussel immune defence.  相似文献   

Acoustic reflectors in the surface layers of deep sea sediments     

D. M. McCann  F. C. D. Dewes 《Marine Geophysical Researches》1972,1(4):362-380

Using ultrasonic scanning it is possible to display the position of an acoustic discontinuity within a sediment core and the amplitude of the reflected signal which results from it. From these results it has been possible to examine the effect of variations in the geotechnical properties on the reflection of compressional waves at normal incidence within the core at a frequency of 100 kHz. The occurrence of acoustic reflectors in the surface layers of North Atlantic sediments has also been examined.Two ultrasonic scanning systems for the non-destructive testing of marine sediment cores have been developed. The performance of the two systems has been evaluated using the results from measurements made on a suite of marine sediment cores from the North Atlantic in conjunction with X-ray scanning and geological analysis of the same cores.  相似文献