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Ezer Tal Carniel Sandro Amin Chabchoub de Camargo Ricardo Estrada-Allis Sheila N. Gao Guoping Greatbatch Richard J. Lermusiaux Pierre F. J. Liu Zhiyu Miyazawa Yasumasa Forster Alejandro Orfila Panickal Swapna Phillips Helen Pinones Andrea Stanev Emil Volker Christoph Xu Fanghua Young Emma 《Ocean Dynamics》2023,73(1):35-38
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Zonal distribution features of high frequency planetary waves in the oceans derived from satellite altimeter data 总被引：2，自引：1，他引：1
1IntroductionTheavailabilityofnearly9aofhighqual-itysealevelanomaly(SLA)datafromsatellitealtimetersmakesitnowpossibletoestimatethedominantsignalsofvariabilityintheglobalo-ceanmoreaccuratelythanwaspreviouslypos-sible.Moreover,mergingtheT/PandERS-1and2altimeterdatathroughanadvancedglobalobjectiveanalysiscangreatlyimproveoura-bilitytoaccuratelyestimateoceanicvariabili-tycomparedwithusingasinglealtimeter(BoulagerandMenkes,1995).ThealtimeterdatarevealthedominantroleofplanetaryRoss-bywavesinocea… 相似文献
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Ocean Dynamics - Sea level rise (SLR) is causing acceleration in the frequency and duration of minor tidal flooding (often called “sunny-day” or “nuisance” flooding) along... 相似文献
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Recent studies show that in addition to wind and air pressure effects, a significant portion of the variability of coastal sea level (CSL) along the US East Coast can be attributed to non-local factors such as variations in the Gulf Stream and the North Atlantic circulation; these variations can cause unpredictable coastal flooding. The Florida Current transport (FCT) measurement across the Florida Straits monitors those variations, and thus, the study evaluated the potential of using the FCT as an indicator for anomalously high water level along the coast. Hourly water level data from 12 tide gauge stations over 12 years are used to construct records of maximum daily water levels (MDWL) that are compared with the daily FCT data. An empirical mode decomposition (EMD) approach is used to divide the data into high-frequency modes (periods T < ～30 days), middle-frequency modes (～30 days < T < ～90 days), and low-frequency modes (～90 days < T < ～1 year). Two predictive measures are tested: FCT and FCT change (FCC). FCT is anti-correlated with MDWL in high-frequency modes but positively correlated with MDWL in low-frequency modes. FCC on the other hand is always anti-correlated with MDWL for all frequency bands, and the high water signal lags behind FCC for almost all stations, thus providing a potential predictive skill (i.e., whenever a weakening trend is detected in the FCT, anomalously high water is expected along the coast over the next few days). The MDWL-FCT correlation in the high-frequency modes is maximum in the lower Mid-Atlantic Bight, suggesting influence from the meandering Gulf Stream after it separates from the coast. However, the correlation in low-frequency modes is maximum in the South Atlantic Bight, suggesting impact from variations in the wind pattern over subtropical regions. The middle-frequency and low-frequency modes of the FCT seem to provide the best predictor for medium to large flooding events; it is estimated that ～10–25% of the sea level variability in those modes can be attributed to variations in the FCT. An example from Hurricane Joaquin (September–October, 2015) demonstrates how an offshore storm that never made landfall can cause a weakening of the FCT and unexpected high water level and flooding along the US East Coast. A regression-prediction model based on the MDWL-FCT correlation shows some skill in estimating high water levels during past storms; the water level prediction is more accurate for slow-moving and offshore storms than it is for fast-moving storms. The study can help to improve water level prediction since current storm surge models rely on local wind but may ignore remote forcing. 相似文献
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According to the work of Truran and Cameron, and of others, on the chemical evolution of the Galaxy, the first generation of stars in the Galaxy contained principally massive objects. If big-bang nucleosynthesis was responsible for the formation of helium, the first generation of stars would contain about 80% hydrogen and 20% helium, to be consistent with the approximately 22% helium found in recent stellar evolutionary studies of the Sun. The present investigation has followed the pre-main sequence evolution and the main sequence evolution of stars of 5, 10, 20, 30, 100, and 200M
. Normal stars in this entire mass range normally convert hydrogen into helium by the CN-cycle on the main sequence. the present hydrogen-helium stars of 5 and 10M
must reach higher central temperatures in order to convert hydrogen to helium by the proton-proton chains. Consequently, the mean densities in the stars are greater, and the surface temperatures are higher than in normal stars. In the stars of 20M
and larger, the proton-proton chains do not succed in supplying the necessary luminosity of the stars by the time the contraction has produced a central temperature near 108K. At that point triple-alpha reactions generate small amounts of C12, which then acts as a catalyst in the CN-cycle, the rate of which is then limited by the beta-decays occurring within the cycle. During the evolution of these more massive stars, the central temperature remains in the vicinity of 108 K, and the surface temperature on the main sequence approaches 105 K. The star of 200M
becomes unstable against surface mass loss through radiation pressure in the later stages of its main sequence evolution, and these mass loss effects were not followed. Young galaxies containing these massive stars will have a very high luminosity, but if they have formed at one-tenth the present age of the universe or later, then the light from them will mainly reside in the visible or ultraviolet, rather than in the infrared as has been suggested by Partridge and Peebles. 相似文献
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Prediction of areas prone to land degradation in agricultural catchments is a complex task. This is due to the difficulties encountered in data gathering over wide regions and in the translation of existing scientific knowledge to a quantitative and spatially explicit risk assessment system. This paper incorporates the use of remotely sensed data, terrain analysis and a multi‐criteria mechanism for evaluating risks of soil loss, water ponding, and sediment deposition in a mid‐size agricultural Mediterranean catchment, under 80 years of intensive cultivation. The research uses simulations to study the effect of topographic attributes, soil characteristics, vegetation cover, rainfall intensity and human activities on the three above‐mentioned processes. The results show that, from the methodological point of view, the integration of knowledge from several experts yields better predictive results than relying on a single expert, even the one found to be most consistent. Also, the use of a simple weighted linear combination was more useful than the more sophisticated computerized programming technique. From the phenomenological point of view, the increase in rainfall intensity and land‐use transformation from orchard to field‐crops has led to a significant increase in soil loss and sediment yield, while extreme changes in tillage direction have only yielded minor changes in water ponding. The developed system's predictive capabilities also show that the outcomes can be used as a basis for decisions on catchment management in regions of high environmental sensitivity. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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The effect of cultivation method on erosion in agricultural catchments: integrating AHP in GIS environments 总被引：1，自引：0，他引：1 
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下载免费PDF全文 The cultivation method used in agricultural catchments can have a great effect on erosion processes; as such, determining the effects on form and degree is crucial. One commonly held hypothesis is that a shift to minimum tillage methods should reduce the rate of erosion. Here, we examine the effect of cultivation methods and environmental conditions on soil erosion risks in field crops and orchards in an agricultural catchment in northern Israel. The examination was conducted using AHP (analytic hierarchy process) and GIS (geographic information system)‐based computer simulations. Field validation of the simulations was conducted during the 2009–2010 winter season. The spatially explicit data on cultivation method, combined with environmental and climatic data, yielded an explanation of most of the variation in erosion risks in the catchment (kappa =0·93). Of the 10 criteria examined, the cultivation method and slope were the two variables with the greatest effect on increased soil erosion. Furthermore, soil loss risks were reduced substantially as a result of substituting conventional tillage with reduced tillage; substituting reduced tillage with conservation tillage; and changing the tillage direction to perpendicular to the direction of the slope. These results are reasonable in light of the modifications that mechanical tools cause in the soil structure, as observed in the penetration depth and the aggregate stability measurements used in this study. Despite the difficulty in collecting spatially explicit data on cultivation methods, we believe that it is of utmost importance to use such data to study erosion risks in agricultural catchments. Copyright © 2014 John Wiley & Sons, Ltd. 相似文献