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81.
Abstract

The Ninth Conference of the Parties (COP-9) decided to adopt an accounting system based on expiring carbon credits to address the problem of non-permanent carbon storage in forests established under the Clean Development Mechanism (CDM). This article reviews and discusses carbon accounting methods that were under consideration before COP-9 and presents a model which calculates the minimum area that forest plantation projects should reach to be able to compensate CDM transaction costs with the revenues from carbon credits. The model compares different accounting methods under various sets of parameters on project management, transaction costs, and carbon prices. Model results show that under current carbon price and average transaction costs, projects with an area of less than 500 ha are excluded from the CDM, whatever accounting method is used. Temporary crediting appears to be the most favorable approach to account for non-permanent carbon removal in forests and also for the feasibility of smaller projects. However, lower prices for credits with finite lifetimes may prevent the establishment of CDM forestry projects. Also, plantation projects with low risk of unexpected carbon loss and sufficient capacity for insuring or buffering the risk of carbon re-emission would benefit from equivalence-adjusted average carbon storage accounting rather than from temporary crediting.  相似文献   
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83.
Because of their fast response to hydrological events, small catchments show strong quantitative and qualitative variations in their water runoff. Fluxes of solutes or suspended material can be estimated from water samples only if an appropriate sampling scheme is used. We used continuous in‐stream measurements of the electrical conductivity of the runoff in a small subalpine catchment (64 ha) in central Switzerland and in a very small (0·16 ha) subcatchment. Different sampling and flux integration methods were simulated for weekly water analyses. Fluxes calculated directly from grab samples are strongly biased towards high conductivities observed at low discharges. Several regressions and weighted averages have been proposed to correct for this bias. Their accuracy and precision are better, but none of these integration methods gives a consistently low bias and a low residual error. Different methods of peak sampling were also tested. Like regressions, they produce important residual errors and their bias is variable. This variability (both between methods and between catchments) does not allow one to tell a priori which sampling scheme and integration method would be more accurate. Only discharge‐proportional sampling methods were found to give essentially unbiased flux estimates. Programmed samplers with a fraction collector allow for a proportional pooling and are appropriate for short‐term studies. For long‐term monitoring or experiments, sampling at a frequency proportional to the discharge appears to be the best way to obtain accurate and precise flux estimates. Copyright © 2006 John Wiley & Sons, Ltd.  相似文献   
84.
Data from the 13 May 1971 β Scorpii occultation by the southern polar region of Jupiter (Vapillon et al., 1973, Astron. Astrophys. 29, 135-149) are re-analyzed with current methods. We correct the previous results for an inacurrate background estimation and calculate new temperature profiles, that are now consistent with the results of other observers of this occultation, as well as with the current knowledge of the jovian atmosphere. The characteristics of the profiles of temperature gradient and the spectral behavior of the temperature fluctuations are found to be similar to the results of previous investigations of planetary atmospheres and in agreement with the presence of atmospheric propagating gravity waves in the jovian atmosphere. We use a wavelet analysis of the temperature profiles to identify the dominant modes of wave activity and compare the reconstructed temperature fluctuations to model-generated gravity waves.  相似文献   
85.
86.
The present paper is a brief report of how, along the lines of a previous paper, the implementation of the program KEPLER1, for the numerical integration of the perturbations of the Kepler problem, has been carried out.  相似文献   
87.
A Lagrangian analysis was applied to the outputs of a coupled physical-biogeochemical model to describe the redistribution of nitrate-rich and nitrate-poor surface water masses in the tropical Pacific throughout the major 1997 El Niño. The same tool was used to analyze the causes of nitrate changes along trajectories and to investigate the consequences of the slow nitrate uptake in the high nutrient low chlorophyll (HNLC) region during the growth phase of the event. Three patterns were identified during the drift of water masses. The first mechanism is well known along the equator: oligotrophic waters from the western Pacific are advected eastward and retain their oligotrophic properties along their drift. The second concerns the persistent upwelling in the eastern basin. Water parcels have complex trajectories within this retention zone and remain mesotrophic. This study draws attention to the third process which is very specific to the HNLC region and to the El Niño period. During the 1997 El Niño, horizontal and vertical inputs of nitrate decreased so dramatically that nitrate uptake by phytoplankton became the only mechanism driving nitrate changes along pathways. The study shows that because of the slow nitrate uptake characteristic of the tropical Pacific HNLC system, nitrate in the pre-El Niño photic layer can support biological production for a period of several months. As a consequence, the slow nitrate uptake delays the gradual onset of oligotrophic conditions over nearly all the area usually occupied by upwelled waters. Owing to this process, mesotrophic conditions persist in the tropical Pacific during El Niño events.  相似文献   
88.
We investigate the mesoscale dynamics of the mistral through the wind profiler observations of the MAP (autumn 1999) and ESCOMPTE (summer 2001) field campaigns. We show that the mistral wind field can dramatically change on a time scale less than 3 hours. Transitions from a deep to a shallow mistral are often observed at any season when the lower layers are stable. The variability, mainly attributed in summer to the mistral/land–sea breeze interactions on a 10-km scale, is highlighted by observations from the wind profiler network set up during ESCOMPTE. The interpretations of the dynamical mistral structure are performed through comparisons with existing basic theories. The linear theory of R. B. Smith [Advances in Geophysics, Vol. 31, 1989, Academic Press, 1–41] and the shallow water theory [Schär, C. and Smith, R. B.: 1993a, J. Atmos. Sci. 50, 1373–1400] give some complementary explanations for the deep-to-shallow transition especially for the MAP mistral event. The wave breaking process induces a low-level jet (LLJ) downstream of the Alps that degenerates into a mountain wake, which in turn provokes the cessation of the mistral downstream of the Alps. Both theories indicate that the flow splits around the Alps and results in a persistent LLJ at the exit of the Rhône valley. The LLJ is strengthened by the channelling effect of the Rhône valley that is more efficient for north-easterly than northerly upstream winds despite the north–south valley axis. Summer moderate and weak mistral episodes are influenced by land–sea breezes and convection over land that induce a very complex interaction that cannot be accurately described by the previous theories.  相似文献   
89.
Zusammenfassung Die Ergebnisse der Radar-Echo-Messungen von I. I. Shapiro, welche auf eine Verringerung der Lichtgeschwindigkeit beim Vorübergang des Lichtes an der Sonne hinweisen, werden zusammen mit der Ablenkung des Lichtes und der Verschiebung seiner Spektrallinien wellentheoretisch erklärt. Es genügt hierzu die Annahme eines materiellen lichtwellentragenden Mediums mit einer Dichte unterhalb des empirischen Vakuums; das Medium muss dann radial zur Sonne eine geringe Inhomogenität besitzen, die in entsprechenden kleinen Zusatzgliedern in den Maxwellschen Gleichungen ihren Ausdruck findet.Auf protophysikalischer Grundlage aufbauend wird die Phasengleichung (22) der an der Sonne vorbeigehenden Lichtwellen unter einfachsten Annahmen abgeleitet und integriert; als Resultat ergeben sich die drei genannten Effekte in Übereinstimmung mit der Erfahrung (Gleichung (39), (44), (47)).
Shapiro (1968) published the first results of radar-echo-observations on Venus and Mercury in the neighbourhood of upper conjunctions with the Sun; the observations indicate a decrease of the velocity of light passing the Sun. The theory of Soldner is disproved; and the general relativity is in accord with the observed facts. But not this theory alone. In this publication the deflection of light, decrease of the velocity of light, and displacement of spectral-lines are explained with the aid of a wavetheory. Hereby the assumption of a material medium carrying light-waves is sufficient, the density of which is below that of the empirical vacuum; hence, the medium must have a small inhomogeneityh radial to the Sun, and the Maxwell equations contain small additional terms (Equation (3)). They lead to the field equations (4) and (5). The protophysical fundamentals of the wave-theory (6), (8), (9), (10a) lead to the Equations (12) of wave-phase. If we assume that the behaviour of the light passing the Sun is independent (in first approximation) from the wave-form (F), the Equation (22) of wave-phase, is deduced for simple-periodic waves of light. Figure 1 outlines the slope and deflection of the ray of light by the Sun. Section 5 contains the solution of (22); and Section 6 the results. The constant of inhomogeneity =1/210–5 (of the radius of the Sun) produces a deflection (39) of light passing the Sun. The length of waves of the light approaching the Sun is decreased to a minimum and is increasing with increasing distance from the Sun until the former value ((43) and (44)). The velocity of light approaching the Sun is decreased to a minimum and increases with increasing distance from the Sun to its former value ((46) and (47)).
  相似文献   
90.
The six best known X-ray binaries are investigated according to the two different assumptions on the mechanism of matter supply. From the model of a semi-detached system with a point-like component, rather good estimates for the masses of the stars and the radius of the optical component can be deduced. The stellar wind model appears to be generally insufficient for driving the X-luminosity. Therefore, according to the mass-ratios, the stars may be at the beginning of mass-exchange. Only 3U 1700-37 shows inconsistent observational data.In the frame of the Roche model, the values of the contact phase angles, in the case of one star filling its lobe and a point-like companion, are given in tabular form in the Appendix, as a function of the mass-ratio and the orbital inclination angle. The limiting minimum inclination angle to have an eclipse is also given.This work has been partly supported by a contract of the Consiglio Nazionale delle Ricerche (CNR).  相似文献   
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