Showing papers in "Tellus B in 1985"

Atmospheric mercury—a review*

Abstract: An attempt is made to assess present knowledge about atmospheric mercury: its occurrence in air and precipitation, chemical transformations taking place in the atmosphere, and mercury fluxes to and from the Earth’s surface. Tentative budgets are estimated for mercury in the global atmosphere and in the atmosphere over Europe and Sweden. Major features revealed by this include the following: For the global atmosphere, current anthropogenic emissions are comparable to emissions by natural processes (preindustrial). The present background fluxes are probably significantly augmented by anthropogenic emissions during the industrial era. A dominant fraction (≥80%) of the total mercury in the atmosphere consists of a volatile gaseous mercury form, presumably elemental mercury, Hg O . This mercury has an atmospheric residence time of at least a few months, maybe even one or two years, and is uniformly distributed throughout the troposphere (1-2 ng m -3 . The volatile mercury vapour (Hg O ) is oxidized in the atmosphere to unknown forms that are soluble and can be scavenged by precipitation or dry deposited at the surface. The oxidation process is not known but photochemical oxidants (including ozone) are likely to be important. The atmospheric residence time of the water soluble (non-volatile) mercury is in the range of a few days to a few weeks, corresponding to a characteristic transport distance of up to a few thousand kilometers. Even if a dominant fraction of the mercury emitted from an individual source, such as a chlor-alkali plant, is dispersed regionally or globally. a small fraction (< 10%) is deposited locally. Increases by a factor of 10 to 100. above background deposition rates, have been measured within the nearest km of such plants. At a distance of 10-50 km, the deposition normally approaches the background value. Around a large Swedish smelter, mercury levels in lake sediments are significantly augmented even beyond 50 km from the plant. The contribution to current mercury deposition in Sweden from anthropogenic mercury emissions in other European countries is most likely larger than the contributions from current Swedish emissions. Measurements of mercury in lake sediments and peat bogs show that in southern Scandinavia. the rate of mercury deposition has increased by a factor of about 5 during the last hundred years. The increase in northern Scandinavia is significantly less, at most a factor of two. These increases are caused, most likely, by anthropogenic emissions into the atmosphere mainly within the European region. DOI: 10.1111/j.1600-0889.1985.tb00062.x

The potential storage of carbon caused by eutrophication of the biosphere

Abstract: We use an element-matching approach to examine the hypothesis that the rate of atmospheric CO 2 increase has been reduced by an increased net storage of carbon in forests, coastal oceans, and the open sea caused by eutrophication of the biosphere with nitrogen and phosphorus. We conclude that a reasonable upper limit of about 200 Tg of the estimated total of 7800 Tg of C0 2 -carbon released to the atmosphere in 1980 could have been stored in biotic reservoirs as organic carbon in trees, soils, and aquatic sediments as a consequence of eutrophication. The reason that storage is so limited relative to total carbon release is that the C:N and C:P ratios in the C0 2 -carbon sources (fossil fuels and primary forests) are much larger than the ratios in the sinks (regrowing forests and aquatic sediments) and that N and P supply controls the rate and amount of storage of organic carbon in the available biotic sinks. DOI: 10.1111/j.1600-0889.1985.tb00060.x

CO2 from fossil fuel burning: global distribution of emissions

Abstract: The atmospheric concentration of carbon dioxide is increasing. An important source of this excess carbon dioxide is the burning of fossil fuels for energy uses. This paper describes an estimate of the areal distribution of CO 2 emissions from energy sources. CO 2 from fuel burned in international bunkers is not included nor is CO 2 from gas flaring or cement manufacture. Emissions are calculated on a 5° x 5° grid of latitude and longitude, based primarily on United Nations fuel use data. Fuel consumption data by country, by state within the US, and by province in Canada are used to calculate CO 2 emissions. Distribution of CO 2 emissions within these political entities is based on population distribution, using both discrete population data for subcountry units and population density maps. Aside from errors inherent in the UN fuel data and in our estimates for fuel composition and combustion efficiency, the major sources of error are (a) within-country regional variations in energy use per capita, (b) within-country regional variations in energy sources (e.g., hydroelectric versus coal electric), and (c) errors in our estimates of relative population density within political entities. While we believe regional patterns are accurately represented and that no CO 2 parcel is allocated very far from its correct source grid space, individual emission numbers by grid space are subject to large uncertainty. The final tabulation shows that 90% of total emissions are from the latitude band 20°-60° N, with the highest individual numbers from the grid spaces containing Frankfurt, London, and Tokyo. DOI: 10.1111/j.1600-0889.1985.tb00073.x

Chemical characterization of stratus cloudwater and its role as a vector for pollutant deposition in a Los Angeles pine forest

Abstract: Highly concentrated, acidic stratus cloudwater was monitored as it intercepted a pine forest (Henninger Flats) 25 km northeast of Los Angeles. Observed pH values ranged from 2.06 to 3.87 for over 100 samples collected in 1982 and 1983 with a median value below pH 3. The ratio of nitrate/sulfate in cloudwater samples was between 1.5 and 2: rainwater at the same site had a ratio of approximately I. The solute deposition accompanying several light. spring rains (summing to ~1 % of annual rainfall) was a disproportionate fraction of the annual total: H + . NO 3 and SO 4 2 were ~20% or more. Based on a reasonable estimate of fog precipitation, deposition of sulfate, nitrate and free acidity due to intercepting stratus clouds may be of comparable magnitude as that due to the incident rainfall at Henninger Flats. Cloudwater that had deposited on local pine needles was collected. It was in general more concentrated than ambient cloudwater but with comparable acidity. Enrichment of K + and Ca 2+ in those samples and in throughfall is believed to be due to leaching from foliar surfaces. Injury to sensitive plant tissue has been noted in the literature when prolonged exposure to this severe kind of micro-environment has been imposed. DOI: 10.1111/j.1600-0889.1985.tb00058.x

Modelling of gas flux through bubbles at the air-water interface

Abstract: A theoretical approach to gas transfer by bubbles created by breaking waves at the air-waterinterface is undertaken. Based on a simple model, this study affords a basic understanding of thephysical mechanisms. The behaviour of a single bubble is examined. Similarities and differencesbetween the formulation of gas fluxes across a “flat” air-water interface and through bubbles areshown. The gas flux through bubbles is not strictly proportional to the solubility and to thedifference of concentrations between the bulk of the water and the surface. Nevertheless, fortrace gases, a linear relationship with this difference of concentrations, increasing with solubilityis predicted. Overpressure in the bubbles and dissolution favour invasion into the water andimply a water supersaturation at equilibrium. This supersaturation is more important when thegas solubility is low. The r61e of surfactants is studied and it is found that they can reduce the gasexchange by a factor of 5. The consequences of the model for the transfer velocity are brieflypresented. A better definition of the bubble lifetime, i t . , a better representation of waterdynamics under a breaking wave, is necessary to make more reliable model predictions, mostimportantly for gases with low solubility. Theoretical studies on the bubble source are necessaryin order to avoid, as far as possible, the use of the bubble distribution. DOI: 10.1111/j.1600-0889.1985.tb00075.x

An atmospheric selenium budget for the region 30° N to 90° N

Abstract: Using a mass balance approach, an atmospheric selenium budget for the region 30° N-90° N has been constructed. The atmosphere was assigned four different aerosol burdens corresponding to mean selenium aerosol concentrations in urban, intermediate (rural). rernote/continental, and oceanic air. The budget calculations indicate that nearly all atmospheric selenium originates from anthropogenic emissions and biological activity in terrestrial and marine ecosystems. After comparing the sources of selenium to those of sulphur it is concluded that there are many similarities in their atmospheric cycling, but that there are also important differences. DOI: 10.1111/j.1600-0889.1985.tb00057.x

Kinetic fractionation of the carbon isotopes 13C and 12C during transfer of CO2 from air to seawater

Abstract: Laboratory experiments have been performed to determine the kinetic fractionation between 13 CO 2 and 12 C0 2 as CO 2 invades seawater. Knowledge of this fractionation. which is regulated by physical and chemical processes in the ocean boundary layer. is important for ocean-atmosphere models which use 13 CO 2 as a tracer. Until now, only theoretical calculations have been performed to determine this fractionation. The experimental results give a fractionation of -2.4 ± 2.0‰ while the calculated value for invasion is -2.1 ± 0.3‰ (i.e. 13 CO 2 invading slower). The results show that the fractionation of CO 2 during invasion into a hydroxide solution (- 14‰) is clearly too high as a value for invasion into seawater and should no longer be used as an upper limit in CO 2 models. DOI: 10.1111/j.1600-0889.1985.tb00061.x

Measurement of stratosphere-to-troposphere exchange in Antarctica by using short-lived cosmonuclides

Abstract: We have monitored the atmospheric concentrations of Be-7 and P-32 at the French Antarctic station "Dumont d'llrville" from 1977 to 1981. The results show that the mean monthly value of the air flux exchanged between stratosphere and troposphere is particularly high close to Antarctica. reaching up to 60 kg m -2 day -1 . DOI: 10.1111/j.1600-0889.1985.tb00059.x

Microparticles in snow from the South Greenland ice sheet

Abstract: A detailed analysis of the concentration and the size distribution of insoluble microparticles (dust) in snow from the South Greenland ice sheet covering the years 1980-1983 has been carried out. An approximative description of the temporal variations of the size distributions has been obtained using Junge distributions to describe the general features of the measured size distributions in the size interval 0.55-2.5 μm. Variations of the 3 measured parameters, the bulk dust concentration, No 0,5 , the slope of the Junge distribution, β, and the δ 18 O value of the snow are compared and discussed. The slope, p, varies seasonally, i.e., low values in winter and high in summer, and β appears to be closer related to the δ 18 O values of the snow than the bulk dust Concentration. In conclusion, analysis of the dust-size distribution may help to improve stratigraphic ice-core dating. The δ 18 O values of the snow are found to vary in parallel with the temperature at coastal stations in South Greenland. This opens the possibility to date snow strata of the order of a month, provided that diffusion has not yet obliterated the subannual variations of δ 18 0. DOI: 10.1111/j.1600-0889.1985.tb00076.x

A classification of some inverse problems in geochemical modelling

Abstract: A number of geochemical inversion problems are analysed with the aim of classifying the inherent degree of difficulty and numerical instability involved in the process of obtaining numerical solutions. The approach is to consider relatively abstract representations of the problems so as to concentrate attention on those aspects that cause numerical difficulties. The various geochemical inversion problems are related to numerical differentiation with the order of differentiation indicating the instability of the problem. The less stable problems place more stringent demands on the observational data that are being interpreted, and the results are also more sensitive to any limitations in the formulation of the inversion problem. The examples considered are the determination of CO 2 source strengths, the deconvolution of trace gas concentrations from polar ice and interpretation of CCl 3 F observations. The calibration of global carbon cycle models is described schematically as a sequence of poorly-conditioned problems. DOI: 10.1111/j.1600-0889.1985.tb00071.x

A parameterization for absorption due to the A, B, and γ oxygen bands

Abstract: A new parameterization for the absorption of visible solar radiation due to 0 2 is presented. This broad band parameterization is based on comparison with detailed line-by-line calculations and is shown to be in excellent agreement with laboratory measurements. The importance of solar 0 2 absorption to atmospheric heating rates and temperatures is also discussed. Although the heating caused by the solar 0 2 bands is small (<0.03 K day -1 ), its presence warms the tropical tropopause region by as much as 1.1 K. Finally, the importance of correct asymptotic limits for modeling the absorptance of 0, 2 is illustrated. DOI: 10.1111/j.1600-0889.1985.tb00040.x

Solar absorption by atmospheric water vapor: a comparison of radiation models

Abstract: We have intercompared several different procedures for evaluating solar absorption by atmospheric water vapor, and in particular we have employed a random band model as a diagnostic tool for assessing approximations which are inherent in existing parameterizations. We reaffirm McDonald's (1960) conclusion as to the importance of the 0.72 and 0.81 μm water vapor absorption bands, and we find that the Goody random band model and the Lacis-Hansen empirical parameterization produce comparable tropospheric heating rates. This agreement does not extend to the stratosphere. for which water vapor amounts lie outside the intended range of applicability of the Lacis-Hansen parameterization. But when diurnal averaging is taken into account, the disagreement is reduced. We further present what is in effect a two-parameter extension of the Lacis-Hansen parameterization. DOI: 10.1111/j.1600-0889.1985.tb00055.x

The occurrence of sulfate‐rich rains in the Negev desert, Israel

Abstract: Rain water was sampled in the Negev Desert, Israel for the past six years. Events with relatively high amounts of sulfate were detected and studied for their chemical, isotopic and synoptic features. It was found that sulfate-rich rain events were usually enriched with respect to the median isotopic value for the area δ 18 O(‰) (relative to SMOW) and were associated with dust storms and a continental direction of surface winds prior to the rain event. DOI: 10.1111/j.1600-0889.1985.tb00064.x

Ice nucleus measurements: effect of site location and weather

Abstract: Filter samples of atmospheric aerosol were collected daily at a city and a rural site over anextended period. The filters were processed in an environment supersaturated with respect to icein order to activate ice nuclei. The concentration of nuclei detected at the two sites was comparedwith reference to the local weather and air-mass trajectories. The city environment generally hasa larger ice nucleus concentration than the rural site. However, fluctuations in the concentrationsat the two sites are usually in phase, indicating a pre-dominantly common origin. With air-masstrajectories over industrial regions, the nucleus concentration is increased. Local weather has aprofound effect: in particular, rain and snow cause substantial reductions in ice nucleusconcentration. DOI: 10.1111/j.1600-0889.1985.tb00077.x

Principles of constrained inversion in the calibration of carbon cycle models

Abstract: The calibration of carbon cycle models by using techniques of constrained inversion is described.These techniques provide a systematic means of assessing the uncertainties in the calibration.The specific calibration technique is analysed in terms of the requirements of carbon cyclestudies, and the relation to other constrained inversion formalisms is discussed. As an example ofthe technique, a linearized version of the box-diffusion model is calibrated. DOI: 10.1111/j.1600-0889.1985.tb00041.x

Solubility of ammonia in water in the presence of atmospheric CO2

Abstract: The equilibrium solubility of ammonia in water. in the presence of atmospheric CO 2 . has been determined at room temperature over the aqueous phase concentration range 75-1200 micromolar. In contrast to a previous study, we find no evidence of a deviation from Henry’s Law occasioned by the presence of atmospheric CO 2 . We therefore conclude that the solubility of ammonia in cloud and rainwater should be adequately described by traditional solubility theory. DOI: 10.1111/j.1600-0889.1985.tb00043.x

Comparative estimates of climatic consequences of Martian dust storms and of possible nuclear war

Abstract: We present a simple analytical model which yields estimates of the temperature of the surface T s and mean atmospheric temperature T a of a planet. The model considers radiative energy balance at the top of the atmosphere and at the underlying surface, and absorption and scattering within the atmosphere, for globally averaged conditions. The model gives reasonable estimates for (a) T s and T a for both clean and dusty Martian atmospheres, (b) and for clean and dusty (asteroid impact) atmospheres of Earth, and (c) the change in T s for the Earth’s atmosphere when the CO 2 content is doubled. When applied to the “war aerosol loaded” terrestrial atmosphere, the model produces results similar to those obtained by Turco, Toon, Ackerman. Pollack and Sagan (TTAPS) and others. However, the analytical nature of the present model exposes certain features which are not revealed by more numerically complicated studies. and this is a matter of particular importance when analysing the consequences of the large uncertainties in smoke injection rates into the atmosphere. Thus the model shows that the sharpest and main changes in T s occur when the optical depth in the visible t s is of order unity or less. reaches the minimum at t s ≈ 3. and then, as r s increases further, T s slowly recovers to the effective temperature T e determined by the balance at the top of the atmosphere. This means the decrease in T s associated with very heavy loading would be followed by a further decrease in T s when the aerosol begins to settle out. The other important result is the atmospheric temperature T a over ocean may be considerably higher than T a over land. Qualitative arguments indicate how aerosol loading might change general circulation patterns and suppress the hydrological cycle. DOI: 10.1111/j.1600-0889.1985.tb00065.x

Atmospheric carbon dioxide variations in the suburbs of Sendai, Japan

Abstract: The concentration of atmospheric CO 2 was measured continuously in the suburbs of Sendai, Japan for the period December 1978-June 1981. The diurnal CO 2 variation was greatest in July and August and was barely observable during the cold months from November to April. The seasonal CO 2 variation was highly irregular and a decrease of CO 2 concentration with height was found throughout the year, presumably reflecting a substantial influence of local soil respiration. Daily minimum values of CO 2 concentration, however, showed a fairly regular seasonal trend and an average rate of CO 2 increase of 1.6 ppmv yr -1 . which are very close to the results of our aircraft measurements in the lower troposphere for the same period. DOI: 10.1111/j.1600-0889.1985.tb00042.x

pH of bulk precipitation during 3 consecutive annual courses in the Trachypogon savannas of the Orinoco Llanos, Venezuela

Abstract: Bulk precipitation was daily collected and individual pH measured at the Trachypogon savannas, Venezuela, over a consecutive 3-year period. The volume-weighted mean pH as calculated, were 5.8, 5.6 and 5.8 for 1981, 1982 and 1983, respectively. The annual variation of pH ranged from 4.9 to 6.9: 4.8 to 6.3 and 5.4 to 6.8 units in 1981, 1982 and 1983, respectively. However, in this savanna area, which is relatively remote from heavy sources of industrial pollution, the annual proportion of daily rains with pH < 5.0, occurring mainly at the onset and end of the wet season, were 2.0,3.0 and 0.0% for 1981, 1982 and 1983, respectively. DOI: 10.1111/j.1600-0889.1985.tb00078.x

On radiative heating due to polar stratospheric clouds

Abstract: Recent satellite observations of polar stratospheric clouds (PSCs) and the theoretical explanation of their formation brought up questions on the radiative effects of those thin clouds. Optical parameters are calculated for selected stages of the cloud development and for wavelengths between I and 40 μn. Radiative transfer calculations yield absolute values of heating rates of about 0.03 K/day for the thickest polar stratospheric clouds observed by the SAM II satellite. The top portion of the cloud is characterized by cooling of the order of 0.01 K/day while thr lower and denser part of the cloud may experience either cooling or warming depending on the thermal structure and on the vertical distribution of clouds in the troposphere. Due to the correlation between cold stratosphere and warm troposphere, the radiative effect appears more sensitive to the distribution of cloud than to the strength of the surface temperature inversion. Unlike most tropospheric cases and under favorable conditions, the growth of cloud particles may reach equilibrium not only by depletion of ambient moisture but also by thermal equilibrium. The hypothetical fully developed cloud would lead to absolute values of the heating rates of the order of 1 K/day. The maximum warming is found in the wings of the I5 μm CO 2 band and extends up to 24 μm, while some cooling occurs at the upper end of the thermal spectrum. A simple parameterization of optical properties of PSCs is presented for inclusion into broad band radiation models. DOI: 10.1111/j.1600-0889.1985.tb00069.x

The chemistry and microphysics of intrastorm sequential precipitation samples

Abstract: A slow moving cold front, which deposited over 40 mm of rain, was investigated for relationshipsbetween pH, ion concentrations and precipitation microphysics. For the first time. precipitationdroplet size spectra were available using a Particle Measuring System’s ground-basedprecipitation probe. The precipitation spectra allowed a preliminary analysis of below cloud rainscavenging: adsorption and impaction.The cumulative rate of chemical precipitation versus cumulative water indicated two differentslopes for the major ions contributing to the acidity of the precipitation. The slopes wereconsistent with a convective stage and a non-convective storm stage and this was consistent withrate of precipitation. DOI: 10.1111/j.1600-0889.1985.tb00063.x

A non-stationary model for sulphur aerosol depletion and deposition in a young spruce stand

Abstract: A non-stationary partial differential equation (pde) of aerosol concentration in one space coordinate z (height above ground) is given. Submodels for the structure and aerodynamics of a young Norway spruce stand (height ~6 m) are developed from site-specific empirical data during a dry, stagnant summer period. The submodels and an empirical time series over 120 h for above-stand sulphur aerosol concentrations are used to quantify the pde and its upper boundary conditions. A simplified analysis indicates an uncertainty within one order of magnitude associated with this step. The pde-predictions of within-stand concentrations are within a factor of 2 of corresponding empirical concentration data. The associated deposition patterns show a diurnal variation and a complex z-dependency. Model improvements and further evaluation methods are suggested. The overall results suggest that estimates of aerosol deposition to forests based only on yearly and regional averages overlook strongly time and space dependent deposition patterns. DOI: 10.1111/j.1600-0889.1985.tb00072.x

A paramaterization for the absorption due to the near infrared bands of CO 2

Abstract: A broad band absorption parameterization for the near-infrared bands of CO 2 is described. This parameterization is in excellent agreement with more detailed line-by-line calculations for a large range of pressures, temperatures and amounts of CO 2 . The role of near IR absorption due to CO 2 is investigated for the earth’s atmosphere. It is shown that the presence of these near-lR absorption bands contributes to a heating of nearly 0.2 K/day in the upper stratosphere and 0.05 K/day in the lower stratosphere. Although the magnitude of heating in the lower stratosphere is small, it contributes more heating than ozone near the tropical tropopause region. DOI: 10.1111/j.1600-0889.1985.tb00068.x

Terrain-induced effects on the ozone, temperature and water vapour daily variation in the upper part of the PBL over hilly terrain

Abstract: Measurements of the daily variation of several meteorological and chemical parameters in theplanetary boundary layer above the crest-height of a mountain-valley system of the SwissPlateau are presented. On the basis of the observations, it is concluded that processes at theearth-atmosphere boundary are contributing strongly to the ozone losses, the increase inhumidity, and the cooling rates observed during night-time at these higher levels. Surface-layereffects are coupled to the upper part of the boundary layer by transport processes, which resultfrom the orographic forcing of the mean wind field (i.e. occurrence of the phenomenon ofblocking) and the interaction of mean flow with locally-induced wind systems. Thus theobservations cannot be interpreted purely by local effects. In this part of the planetary boundarylayer, the additional influence of processes due to the complex topography on a more regionalscale is also felt. It is stressed that this coupling should be adequately represented in atmosphericpollution models of non-homogeneous terrain. DOI: 10.1111/j.1600-0889.1985.tb00074.x

Stratospheric HTO perturbations 1980-1983

Abstract: Three perturbations of the stratospheric tritiated water burden have occurred. An atmosphericnuclear detonation in 1980 injected about 2.1 MCi. The massive eruptions of the volcano El Chichon may have contributed to a doubling of the removal rate in 1982. An unusually largewintertime exchange with the upper stratosphere may have occurred between 1982 and 1983. DOI: 10.1111/j.1600-0889.1985.tb00044.x

A model for the estimation of precipitable water

Abstract: A model has been developed for the estimation of precipitable water on clear days based on thedaily and hourly measurements of global IR solar radiation and on humidity data taken atground level The model takes into account the attenuation processes of radiation by watervapour The results concerning precipitable water are compared with those obtained withradiosondes both for daily and hourly intervals obtaining correlation coefficients higher thanthose achieved with the equations proposed by Reitan and Smith in which only humidityparameters are used The model has been applied to three periods: cold (October-March), warm(April-September) and annual (January-December) over 3 years in Salamanca (central N-WSpain) DOI: 101111/j1600-08891985tb00070x

On the climatic relevancy of Arctic Haze: static energy balance considerations

Abstract: Optical properties of Arctic Haze are known only roughly, but seem to be bracketed in the following ranges: optical depth, 0.1 to 0.5; haze asymmetry factor, 0.6 to 0.7; albedo of single scattering, 0.8 to 0.98. On the basis of these numbers, simple static energy balance considerations suggest that the light-absorbing haze over the northern reflecting ice cap creates an earthatmosphere warming of 0.1 to l.O°C in comparison to a hypothetical haze-free Arctic. Before elaborate climatic models can be run with such meaning, the optical properties of the Arctic Haze, its geographical extent and seasonal variation have to be determined more accurately. DOI: 10.1111/j.1600-0889.1985.tb00046.x

Calculation of ground temperature and fluxes by surface models: a comparison with experimental data in the African savannah

Abstract: In large-scale models, an accurate calculation of energy fluxes at the lower boundary is important to ensure satisfactory predictions of the meteorological parameters. This work is performed using surface models. In this paper. various surface models. previously studied by Deardorff are tested against experimental data from the West African Monsoon Experiment 1979 in the Ivory Coast. Physical properties of the soil are assumed constant and uniform. Input variables are dry and wet bulb temperatures. wind velocity at the 2 m level, and global radiation. We compute sensible and latent heat fluxes and the surface conduction flux. A Crank-Nicholson scheme has been used with a time step of 5 min. Estimated sensible and latent heat fluxes agree well with experimental data. The order of magnitude of the difference between theoretical and experimental values is 30 W m -2 for evaporation and 20 W m -2 for sensible heat. Surface soil heat flux ie less satisfactorily calculated. which could result from properties assumed constant such as soil surface humidity. A model including the heat conduction in the soil provides the best results. The others, based on empirical formulations of surface soil heat flux, are less satisfactory. However. with a simple two-layer model. the predictions are quite acceptable. DOI: 10.1111/j.1600-0889.1985.tb00056.x

The role of baroclinic eddies in mixing tritium into the oceanic gyres

Abstract: (1985). The role of baroclinic eddies in mixing tritium into the oceanic gyres. Tellus B: Chemical and Physical Meteorology: Vol. 37, No. 3, pp. 182-185.