Analysis of aircraft measurements of momentum flux in the subcloud layer over the tropical atlantic ocean during gate     

Gary K. Greenhut 《Boundary-Layer Meteorology》1981,20(1):75-100

The momentum flux data obtained by the gust probe aboard the NOAA DC-6 aircraft during GATE are analyzed. Vertical profiles are obtained for Phases I and III and correlated with vertical wind velocity profiles using the geostrophic departure method. Reasonable agreement is obtained using the horizontal equations of motion with negligible advective acceleration. The vertical profiles of momentum flux and wind speed variance compare well with the numerical model results of Deardorff (1972) and Wyngaard et al. (1974). Vertical distributions of power spectra for vertical eddy motion and cospectra corresponding to the momentum flux components are obtained along with the height variation of the dominant length scales of vertical eddy motion and the dissipation rate of turbulence kinetic energy. When normalized by mixed-layer similarity, these results agree well with previous determinations in the boundary layer over tropical oceans and over land.  相似文献   

A comparison of tropical oceanic heat fluxes determined by airborne eddy correlation and shipboard bulk aerodynamic techniques     

Roger F. Reinking  Gary Barnes 《Boundary-Layer Meteorology》1981,20(3):353-370

Vertical turbulent transports of latent and sensible heat through the tropical marine boundary layer were measured with ship and airborne instruments in the GATE experimental area. The measurements from the two systems are compared for cases of simultaneous sampling in the same locations during undisturbed weather and during the wakes of convective disturbances. The paired average fluxes from the airborne eddy correlation measurements and the shipboard bulk aerodynamic measurements, for undisturbed weather, are related with correlation coefficients in the range of 0.6 to 0.9; the correlations depend primarily on stratifications of the aircraft data according to sampling altitude (15–153 m msl) and flight pattern relative to the mean wind. The agreement between the two types of measurements is best for ship data paired with aircraft samples from the lowest altitudes (15 and 30 m) and from alongwind rather than crosswind flights, as is appropriate since the stationary ships monitor the alongwind characteristics of the turbulence. The use of long (1–3 hr) versus short (10 min) ship samples did not significantly affect the comparability with the aircraft samples during undisturbed periods.The good baseline comparability demonstrated by the undisturbed-weather comparisons was applied to interpret the results from the wakes behind showers. Although these paired measurements were few, not only the sensible heat, but also the latent heat flux was shown to decrease substantially with altitude from 10 m to at least 150 m in the wakes, where the mixing was relatively intense. Variations in the fluxes were much greater at the higher level than nearer the sea surface.  相似文献   

The high-temperature heat capacity of natural calcite (CaCO3)     

Gary K. Jacobs  Derrill M. Kerrick  Kenneth M. Krupka 《Physics and Chemistry of Minerals》1981,7(2):55-59

The heat capacity (C _P) of a natural sample of calcite (CaCO₃) has been measured from 350 to 775 K by differential scanning calorimetry (DSC). Heat capacities determined for a powdered sample and a single-crystal disc are in close agreement and have a total uncertainty of ±1 percent. The following equation for the heat capacity of calcite from 298 to 775 K was fit by least squares to the experimental data and constrained to join smoothly with the low-temperature heat capacity data of Staveley and Linford (1969) (C _P in J mol^?1 K^?1, T in K): $$\begin{gathered} C_p = - 184.79 + 0.32322T - 3,688,200T^{ - 2} \hfill \\ {\text{ }} - (1.2974{\text{ }} \times {\text{ 10}}^{ - {\text{4}}} )T^2 + 3,883.5T^{ - 1/2} \hfill \\ \end{gathered} $$ Combining this equation with the S ₂₉₈ ⁰ value from Staveley and Linford (1969), entropies for calcite are calculated and presented to 775 K. A simple method of extrapolating the heat capacity function of calcite above 775 K is presented. This method provides accurate entropies of calcite for high-temperature thermodynamic calculations, as evidenced by calculation of the equilibrium: CaCO_{3 (s)}=CaO_(s)+CO_{2 (s)}.  相似文献   

Adjustments of the fluvial system. D. D. Rhodes and G. P. Williams (eds), proceedings volume of the tenth annual geomorphology symposium,binghampton, New York,U.S.A., Kendall/Hunt Publishing Co., Inc., Dubuque,Iowa, U.S.A., 1979. no. of pages: 372     

Gary Parker 《地球表面变化过程与地形》1981,6(5):494-494

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Drag coefficient and roughness length determinations on an Alaskan Arctic Coast during summer     

C. D. Walters Jr. 《Boundary-Layer Meteorology》1975,8(2):235-237

Field data collected over land and water near Point Lay, Alaska, yielded determinations of the aerodynamic roughness lengths and drag coefficients over three locations on an arctic barrier island and over the Chukchi Sea. The agreement between the results over the sea and previous published results from data taken at approximately the same latitude in the Beaufort Sea is excellent.  相似文献   

Silicic differentiates of abyssal oceanic magmas: Evidence for late-magmatic vapor transport of potassium     

John M. Sinton  Gary R. Byerly 《Earth and Planetary Science Letters》1980,47(3):423-430

Massive, nearly holocrystalline dolerites from DSDP Hole 417D contain from 0.5 to 1.5% of granophyric patches composed mainly of Na-plagioclase and quartz. These patches are compositionally similar to other crystalline silicic rocks from oceanic spreading centers and differ from rarer abyssal silicic glasses. Crystalline varieties withSiO₂60wt.% generally haveNa/K>10, whereas silicic glasses have Na/K in the range 3–6. While crystal fractionation readily accounts for the Na₂O and K₂O contents of abyssal silicic glasses, both the 417D granophyres and other crystalline abyssal silicic rocks have much lower K₂O than that predicted by any reasonable crystal-liquid fractionation model. We propose that high-temperature vapor phase transport is responsible for removal of potassium during late-stage crystallization of these rocks. This allows for the formation of cogenetic silicic glassy and crystalline rocks with greatly different Na/K ratios. These observations and interpretations lead to a more confident assignment of high Na/K silicic rocks of oceanic and ophiolitic environments to a cogenetic origin with basaltic oceanic crust.  相似文献   

Sea-Level Change: The Expected Economic Cost of Protection Or Abandonment in the United States   总被引：2，自引：0，他引：2  

Gary W. Yohe  Michael E. Schlesinger 《Climatic change》1998,38(4):447-472

Three distinct models from earlier work are combined to: (1) produce probabilistically weighted scenarios of greenhouse-gas-induced sea-level rise; (2) support estimates of the expected discounted value of the cost of sea-level rise to the developed coastline of the United States, and (3) develop reduced-form estimates of the functional relationship between those costs to anticipated sea-level rise, the cost of protection, and the anticipated rate of property-value appreciation. Four alternative representations of future sulfate emissions, each tied consistently to the forces that drive the initial trajectories of the greenhouse gases, are considered. Sea-level rise has a nonlinear effect on expected cost in all cases, but the estimated sensitivity falls short of being quadratic. The mean estimate for the expected discounted cost across the United States is approximately $2 billion (with a 3% real discount rate), but the range of uncertainty around that estimate is enormous; indeed, the 10th and 90th percentile estimates run from less than $0.2 billion up to more than $4.6 billion. In addition, the mean estimate is very sensitive to associated sulfate emissions; it is, specifically, diminished by nearly 25% when base-case sulfate emission trajectories are considered and by more than 55% when high-sulfate trajectories are allowed.  相似文献   

Conducting and Interpreting Slug Tests in Monitoring Wells with Partially Submerged Screens     

Gordon K. Binkhorst  Gary A. Robbins 《Ground water》1998,36(2):225-229

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Quantifying groundwater discharge to a small perennial stream in southern Ontario, Canada   总被引：3，自引：0，他引：3  

Edwin E. Cey  David L. Rudolph  Gary W. Parkin  Ramon Aravena 《Journal of Hydrology》1998,210(1-4):21-37

A study of the interaction between groundwater and surface water was undertaken within a small agricultural watershed in southern Ontario, Canada. Groundwater contributions to streamflow were measured along a section of stream during baseflow conditions and during rainfall events. Four techniques were used to estimate the contribution of groundwater to the stream along a 450 m reach (three during baseflow and one during stormflow conditions). Under baseflow conditions, streamflow measurements using the velocity–area technique indicated that the net groundwater flux to the stream during the summer months was 10 ml s⁻¹ m⁻¹. Hydrometric measurements (i.e. hydraulic gradient and hydraulic conductivity) taken using mini-piezometers installed in the sediments beneath the stream resulted in net groundwater flux estimates that were four to five times lower. Seepage meters failed to provide any measurements of water flux into or out of the stream. Therefore, based on these results, the velocity–area technique gives the best estimate of groundwater discharge. Hydrograph separations were conducted using isotopic ratios and electrical conductivity on two large rainfall events with different antecedent moisture conditions in the catchment. Both events showed that pre-event water (generally considered groundwater) dominated streamflow and tile drain flow with 64%–80% of the total discharge contributed by pre-event water. High water table conditions within the catchment resulted in greater stream discharge and a greater contribution of event water in the streamflow than that observed under low water table conditions for similar intensity storm events. The results also showed that differences in riparian zone width, vegetation and surface saturation conditions between the upper and lower catchment can influence the relative magnitude of streamflow response from the two catchment areas.  相似文献   

Confronting the quadruple global crisis     

Gary A. Dymski 《Geoforum》2010,41(6):837-840

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