A weather-resolving index for assessing the impact of climate change on tourism related climate resources   总被引：2，自引：1，他引：1  

Gongmei Yu  Zvi Schwartz  John E. Walsh 《Climatic change》2009,95(3-4):551-573

This study develops and tests a Modified Climate Index for Tourism (MCIT) utilizing more than 50 years of hourly temperature, wind and significant weather data from contrasting climatic regions, Florida and Alaska. The index measures climate as a tourism resource by combining several tourism-related climate elements. It improves previous methods by incorporating variables that are more relevant to tourism activities, by addressing the overriding nature of some conditions, and by incorporating hourly observations rather than simple daily averages. The MCIT was tested using hourly weather observations from King Salmon, Alaska and Orlando, Florida. The results show that average temperature alone is not sufficient to represent tourism climate resources. For example, at both the Florida and Alaskan sites, showers and thunderstorms are more limiting factors than temperature during much of the year. When applied to past climate data, the proposed MCIT generates meaningful results that capture tourism-related climate variations and trends, including (a) the increasingly favorable tourism conditions in Alaska due to a lengthening of the warm season and (b) a decrease of ideal climatic conditions in central Florida due to the increased summer temperatures. Thus, the index has the potential to become a useful quantitative tool to be used in conjunction with climate models to predict the nature and magnitude of the impact of anticipated climate changes on tourism.  相似文献   

Stress distribution over the Mozambique Ridge     

Vladimir Lyakhovsky  Zvi Ben-Avraham  Margaret Reznikov 《Tectonophysics》1994,240(1-4):21-27

The Mozambique Ridge is an aseismic oceanic plateau in the southwestern Indian Ocean. During the separation of Antarctica and South Africa in the Early Cretaceous, the Mozambique Ridge was segmented by fracture zones which were assumed to become inactive during the Cenomanian, when Africa and Antarctica were finally separated. However, the existence of active normal faulting in the central part of the Mozambique Ridge was demonstrated by single and multichannel seismic surveys. Numerical modelling of the stress distribution caused by the crustal structure of the Mozambique Ridge and the adjacent oceanic basins suggests the possible existence of a zone with average horizontal tension up to 70 MPa along the central part of this passive ridge, which may cause the modern fault activity. These stresses also cause an additional dynamic anomaly which can explain small variations of the geoid anomaly over the ridge.  相似文献   

Eigenrays in 3D heterogeneous anisotropic media,Part II: Dynamics     

Igor Ravve  Zvi Koren 《Geophysical Prospecting》2021,69(1):28-52

This paper is the second in a sequel of two papers and dedicated to the computation of paraxial rays and dynamic characteristics along the stationary rays obtained in the first paper. We start by formulating the linear, second‐order, Jacobi dynamic ray tracing equation. We then apply a similar finite‐element solver, as used for the kinematic ray tracing, to compute the dynamic characteristics between the source and any point along the ray. The dynamic characteristics in our study include the relative geometric spreading and the phase correction due to caustics (i.e. the amplitude and the phase of the asymptotic form of the Green's function for waves propagating in 3D heterogeneous general anisotropic elastic media). The basic solution of the Jacobi equation is a shift vector of a paraxial ray in the plane normal to the ray direction at each point along the central ray. A general paraxial ray is defined by a linear combination of up to four basic vector solutions, each corresponds to specific initial conditions related to the ray coordinates at the source. We define the four basic solutions with two pairs of initial condition sets: point–source and plane‐wave. For the proposed point–source ray coordinates and initial conditions, we derive the ray Jacobian and relate it to the relative geometric spreading for general anisotropy. Finally, we introduce a new dynamic parameter, similar to the endpoint complexity factor, presented in the first paper, used to define the measure of complexity of the propagated wave/ray phenomena. The new weighted propagation complexity accounts for the normalized relative geometric spreading not only at the receiver point, but along the whole stationary ray path. We propose a criterion based on this parameter as a qualifying factor associated with the given ray solution. To demonstrate the implementation of the proposed method, we use several isotropic and anisotropic benchmark models. For all the examples, we first compute the stationary ray paths, and then compute the geometric spreading and analyse these trajectories for possible caustics. Our primary aim is to emphasize the advantages, transparency and simplicity of the proposed approach.  相似文献   

FATTY ACIDS PROFILE IN A HIGH CELL DENSITY CULTURE OF ARACHIDONIC ACID-RICH PARIETOCHLORIS INCISA （TREBOUXIOPHYCEAE, CHLOROPHYTA） EXPOSED TO HIGH PFD   总被引：1，自引：0，他引：1  

Liu Jian-guo  Zvi Cohen  Amos Richmond 《中国海洋湖沼学报》2002,20(2):149-156

The changes in arachidonic acid (AA) and fatty acids profiles along the growth curve ofParietochloris incisa, a coccoid snow green alga, were studied in a 2.8 cm light-path flat photobiorcactor, exposed to strong photon flux density [PFD, 2400 μEmol/(m²·s)]. Sixteen fatty acids were identified by gas chromatography showing that AA was the dominant fatty acid (33%–41%) followed by linoleic acid (17%–21%). AA content was closely investigated with respect to total fatty acids (TFA), ash free dry weight (AFDW) of cell mass as well as total culture content. These parameters were influenced significantly in a similar manner by culture growth phase, i.e., slightly decreasing in the lag period, gradually increasing in the logarithmic phase, becoming maximal at the early stationary phase, starting to decrease at the late stationary phase, sharply dropping at the decline phase. The increase in AA per culture volume during the logarithmic phase was not only associated with the increase in AFDW but also connected with a corresponding increase in AA/TFA, TFA/AFDW as well as AA/AFDW. The sharp decrease in AA content of the culture during the decline phase was mainly due to the decrease in AA/TFA, TFA/AFDW and AA/AFDW, although AFDW declined only a small extent. Maximal AA concentration, obtained at the early stationary phase, was 900 mg/L culture volume, and the average daily net increase of AA during 9 days logarithmic growth was 1.7 g/(m²·day). Therefore, harvesting prior to the decline phase in a batch culture, or at steady state in continuous culture mode seems best for high AA production. The latter possibility was also further confirmed by continuous culture with 5 gradients of harvesting rate. Contribution No. 4138 from the Institute of Oceanology, Chinese Academy of Sciences. Project 39970575 supported by NSFC and A/2786-2 supported by International Foundation for Sciences (IFS).  相似文献   

The evolution of the China Basin and the mesozoic paleogeography of Borneo   总被引：1，自引：0，他引：1  

Zvi. Ben-Avraham  Seiya Uyeda 《Earth and Planetary Science Letters》1973,18(2):365-376

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Near bottom temperature anomalies in the Dead Sea     

Zvi Ben-Avraham  Robert D. Ballard 《Earth and Planetary Science Letters》1984,71(2):356-360

A bottom photographic and temperature study was carried out in the Dead Sea using a miniature version of the unmanned camera system ANGUS (mini-ANGUS). Due to the low transparency of the Dead Sea water, the bottom photographs provide very poor results. Only in a very few locations was the floor visible and in those cases it was found to be a white undulating sedimentary surface.The bottom temperature measurements, which were made continuously along the ship track, indicate the presence of a large zone of temperature anomalies. This zone is located in the deep part of the north basin at a water depth of over 330 m. The anomalies occur above a portion of an east-west fault which cuts through the Dead Sea suggesting the presence of hydrothermal activity.  相似文献   

Internal structure of the Dead Sea leaky transform (rift) in relation to plate kinematics   总被引：13，自引：0，他引：13  

Zvi Garfunkel 《Tectonophysics》1981,80(1-4):81-108

The structures along the Dead Sea transform (rift) are related to the motions of the Sinai and Arabia plates which border it, and to the irregularities of their boundaries. The total slip was 105 km left-lateral, but the present structures were formed mainly during the last 40 km of slip, which probably occurred in the Plio-Pleistocene. Along the southern half of the transform the strike-slip motion takes place on en-echelon faults. This produces rhomb-shaped grabens or pull-aparts, which are sometimes composite, and in which there is local crustal separation. Thus, much of the transform is “leaky”. These structures occur in a morpho-tectonic “rift-valley” delimited by normal faults, which express a small component of transverse extension. Along a few segments the shape of the transform is such that lateral motion produces local transverse compression. The geometric relations of the structures along the transform define an Eulerian pole of relative plate motions at 32.8° N 22.6° E ± 0.5°. The older motion was somewhat different and is described by a pole located about 5° west of the above. Then the component of transverse extension and crustal separation was much smaller than now, while local transverse compression was more important. The northern half of the Dead Sea transform has an irregular shape, and the bordering plates did not remain rigid as lateral motion continued. Here transverse compression is often important.  相似文献   

Isotopic composition of hydration water in gypsum     

Zvi Sofer 《Geochimica et cosmochimica acta》1978,42(8):1141-1149

The isotopic composition of the hydration water of gypsum is a sensitive diagnostic tool for specifying the mechanisms of its formation, either from an evaporating brine, by hydration of anhydriate or in situ formation in surface or groundwaters through oxidation of sulfides. Primarily, gypsum is formed in isotopic equilibrium with the mother brine; later, exchange of water occurs rapidly under humid conditions by means of a mechanism of recrystallization of gypsum or through diffusion of water into the intact crystal. Under arid conditions, however, the primary isotopic record has been preserved, in some instances, since the Pleistocene.  相似文献   

Crustal shear velocity structure across the Dead Sea Transform from two-dimensional modelling of DESERT project explosion seismic data   总被引：3，自引：0，他引：3  

J. Mechie  K. Abu-Ayyash  Z. Ben-Avraham  R. El-Kelani  A. Mohsen  G. Rümpker  J. Saul  M. Weber 《Geophysical Journal International》2005,160(3):910-924

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Seismotectonics of the Sinai subplate – the eastern Mediterranean region     

Amos Salamon  Avraham Hofstetter  Zvi Garfunkel  Hagai Ron 《Geophysical Journal International》2003,155(1):149-173

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