The circulation of the eastern tropical Pacific: A review   总被引：5，自引：9，他引：5  

William S. Kessler   《Progress in Oceanography》2006,69(2-4):181

During the 1950s and 1960s, an extensive field study and interpretive effort was made by researchers, primarily at the Scripps Institution of Oceanography, to sample and understand the physical oceanography of the eastern tropical Pacific. That work was inspired by the valuable fisheries of the region, the recent discovery of the equatorial undercurrent, and the growing realization of the importance of the El Niño phenomenon. Here we review what was learned in that effort, and integrate those findings with work published since then as well as additional diagnoses based on modern data sets.Unlike the central Pacific, where the winds are nearly zonal and the ocean properties and circulation are nearly independent of longitude, the eastern tropical Pacific is distinguished by wind forcing that is strongly influenced by the topography of the American continent. Its circulation is characterized by short zonal scales, permanent eddies and significant off-equatorial upwelling. Notably, the Costa Rica Dome and a thermocline bowl to its northwest are due to winds blowing through gaps in the Central American cordillera, which imprint their signatures on the ocean through linear Sverdrup dynamics. Strong annual modulation of the gap winds and the meridional oscillation of the Intertropical Convergence Zone generates a Rossby wave, superimposed on the direct forcing, that results in a southwestward-propagating annual thermocline signal accounting for major features of observed thermocline depth variations, including that of the Costa Rica Dome, the Tehuantepec bowl, and the ridge–trough system of the North Equatorial Countercurrent (NECC). Interannual variability of sea surface temperature (SST) and altimetric sea surface height signals suggests that the strengthening of the NECC observed in the central Pacific during El Niño events continues all the way to the coast, warming SST (by zonal advection) in a wider meridional band than the equatorially trapped thermocline anomalies, and pumping equatorial water poleward along the coast.The South Equatorial Current originates as a combination of equatorial upwelling, mixing and advection from the NECC, and Peru coastal upwelling, but its sources and their variability remain unresolved. Similarly, while much of the Equatorial Undercurrent flows southeast into the Peru Undercurrent and supplies the coastal upwelling, a quantitative assessment is lacking. We are still unable to put together the eastern interconnections among the long zonal currents of the central Pacific.  相似文献   

Analysis of long time series of long-wave radiation fluxes above a pine forest     

A. Kessler  L. Jaeger 《Theoretical and Applied Climatology》2003,74(3-4):179-189

Summary ?The long-term variations of upward terrestrial (E) and downward atmospheric (A) long-wave radiation fluxes above a pine stand in the southern part of the upper Rhine valley plain are analysed based on monthly mean values from 27 years of monitoring. Equivalent blackbody temperatures of the canopy and the atmosphere are calculated and compared to air temperatures at nearby sites. Based on 324 monthly values each, correlations between A and E as well as A and global radiation G are analysed. Only the former are highly correlated. Monthly mean values of long-wave radiation A can be calculated from air temperature, water vapour pressure and cloud cover. The long-term yearly average of equivalent blackbody temperature of the canopy is 0.6 K lower than kinetic air temperature at nearby sites. Only small, insignificant increases of both blackbody temperatures and air temperature are found. Despite the strong forest growth, it is surprising that the ratio of canopy emission temperature to air temperature did not change significantly. Relationships between the changes of general atmospheric circulation and equivalent blackbody temperatures of the canopy point to a strong dependence on shifts of general atmospheric flow. Received February 24, 2000; revised April 18, 2002; accepted July 20, 2002  相似文献   

Charging El Niño with off-equatorial westerly wind events     

Shayne McGregor  Axel Timmermann  Fei-Fei Jin  William S. Kessler 《Climate Dynamics》2016,47(3-4):1111-1125

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A numerical study of the effects of a large Sandbar upon Sea Breeze development     

R. C. Kessler  D. Eppel  R. A. Pielke  J. McQueen 《Meteorology and Atmospheric Physics》1985,34(1):3-26

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Soil moisture variation and plant water stress at the Hartheim Scots pine plantation     

N. Sturm  S. Reber  A. Kessler  J. D. Tenhunen 《Theoretical and Applied Climatology》1996,53(1-3):123-133

Summary During two measurement campaigns in 1992 (the Hartheim Experiment HartX- and an additional experiment in autumn), measurements of soil moisture were carried out in aPinus sylvestris stand at Hartheim on the Oberrhein. Several methods were used to determine soil water status. They were compared in terms of suitability for estimating stand evapotranspiration (ET) via soil water depletion. Measurements of tree water potential suggested that conductance of the trees was affected by soil water depletion during the period of the HartX campaign in spring 1992. We interpret the observations to indicate a lesser influence of soil water availability on tree transpiration during the autumn experiment.Eddy correlation and xylem sapflow measurements provided reference ET values with which to compare the stand ET calculations based on soil moisture measurements. Profile measurements of soil moisture showed that particularly in springtime when the lower soil layers are saturated with water, the water transport from depths below the major rooting zone is a very important factor affecting evaluation of stand ET. Decreases in soil water storage may be determined best with permanently installed soil moisture sensors such as used in tensiometric or TDR measurements that provide high resolution of changes over time.With 8 Figures  相似文献   

Preface     

R. Vogt  L. W. Gay  J. D. Tenhunen  Ch. Bernhofer  A. Kessler 《Theoretical and Applied Climatology》1996,53(1-3):1-1

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Über den Jahresgang der potentiellen Verdunstung im Titicaca-Becken     

Prof. Dr. Albrecht Kessler 《Theoretical and Applied Climatology》1970,18(3-4):239-252

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Molecular and isotopic partitioning of low-molecular-weight hydrocarbons during migration and gas hydrate precipitation in deposits of a high-flux seepage site     

Thomas Pape  André Bahr  Janet Rethemeyer  John D. Kessler  Heiko Sahling  Kai-Uwe Hinrichs  Stephan A. Klapp  William S. Reeburgh  Gerhard Bohrmann 《Chemical Geology》2010,269(3-4):350-363

Detailed knowledge of the extent of post-genetic modifications affecting shallow submarine hydrocarbons fueled from the deep subsurface is fundamental for evaluating source and reservoir properties. We investigated gases from a submarine high-flux seepage site in the anoxic Eastern Black Sea in order to elucidate molecular and isotopic alterations of low-molecular-weight hydrocarbons (LMWHC) associated with upward migration through the sediment and precipitation of shallow gas hydrates. For this, near-surface sediment pressure cores and free gas venting from the seafloor were collected using autoclave technology at the Batumi seep area at 845 m water depth within the gas hydrate stability zone.Vent gas, gas from pressure core degassing, and from hydrate dissociation were strongly dominated by methane (> 99.85 mol.% of ∑[C₁–C₄, CO₂]). Molecular ratios of LMWHC (C₁/[C₂ + C₃] > 1000) and stable isotopic compositions of methane (δ¹³C = ? 53.5‰ V-PDB; D/H around ? 175‰ SMOW) indicated predominant microbial methane formation. C₁/C₂₊ ratios and stable isotopic compositions of LMWHC distinguished three gas types prevailing in the seepage area. Vent gas discharged into bottom waters was depleted in methane by > 0.03 mol.% (∑[C₁–C₄, CO₂]) relative to the other gas types and the virtual lack of ¹⁴C–CH₄ indicated a negligible input of methane from degradation of fresh organic matter. Of all gas types analyzed, vent gas was least affected by molecular fractionation, thus, its origin from the deep subsurface rather than from decomposing hydrates in near-surface sediments is likely.As a result of the anaerobic oxidation of methane, LMWHC in pressure cores in top sediments included smaller methane fractions [0.03 mol.% ∑(C₁–C₄, CO₂)] than gas released from pressure cores of more deeply buried sediments, where the fraction of methane was maximal due to its preferential incorporation in hydrate lattices. No indications for stable carbon isotopic fractionations of methane during hydrate crystallization from vent gas were found. Enrichments of ¹⁴C–CH₄ (1.4 pMC) in short cores relative to lower abundances (max. 0.6 pMC) in gas from long cores and gas hydrates substantiates recent methanogenesis utilizing modern organic matter deposited in top sediments of this high-flux hydrocarbon seep area.  相似文献   

ISO Observations of Symbiotic Stars     

S.P.S. Eyres  A. Evans  A. Salama  P. Barr  J. Clavel  N. Jenkins  K. Leech  M. Kessler  T. Lim  L. Metcalfe  B. Schulz 《Astrophysics and Space Science》1997,255(1-2):361-366

A number of symbiotic stars have been observed with ISO. In addition to a number of emission lines, SWS observations of the symbiotic novae RR Tel and V1016 Cyg reveal prominent, broad 10 & 18 μm silicate dust features. The 10 μm features are similar to the crystalline silicate profiles seen in classical novae. There is some evidence that the silicate brightness in V1016 Cyg varies with Mira-component phase. However, the silicate feature in RR Tel also showed some variation even though observations were made at very similar Mira-component phases. PHT observations of S-type symbiotic stars show the IR emission to be dominated by the red-giant component. However, an excess in the PHT-P filters from 10 to 15 μm is evident in all the stars, and there may be a broad 3.2 μm absorption feature or a broad 3.8 μm emission feature. At this time we have no adequate physical explanations for any of these features. This revised version was published online in August 2006 with corrections to the Cover Date.  相似文献   

Über Lochverwitterung und ihre Beziehungen zur Metharmose (Umbildung) der Gesteine     

Paul Kessler 《International Journal of Earth Sciences》1922,12(6-8):237-270

Ohne Zusammenfassung  相似文献