Statistics of Scalar Fields in the Atmospheric Boundary Layer Based on Large-eddy Simulations. Part 1: Free Convection

Convection in a quasi-steady, cloud-free, shear-free atmospheric boundary layer is investigated based on a large-eddy simulation model. The performed tests indicate that the characteristic (peak) values of statistical moments at the top of the mixed layer are proportional to the interfacial scales (from gradients of scalars in the interfacial layer). Based on this finding a parameterization is proposed for profiles of scalar variances. The parameterization employs two, semi-empirical similarity functions F_m(z/z_i) andF_i(z/z_i), multiplied by a combination of the mixed-layer scales and the interfacial scales.     

On the origin of copper mineralization in the Kupferschiefer: a suIphur isotope study*

Sulphur isotopic compositions of copper and iron sulphides (dispersed and vein mineralization) from the Polish part of the Kupferschiefer were determined and compared with data from the literature. Most of the δ³⁴S values of sulphides range from about -40 to -25%, indicating sulphide precipitation during bacterial sulphate reduction in an open system which gradually chanes into a closed system. Sulphides from veins are usually enriched in ³⁴S compared to finely dispersed mineralization and were probably formed in a more closed system. Copper sulphides are generally a few permil heavier than pyrite. Coupled with detailed microscopical observations the isotope data suggest that the mineralization is either syngenetic or early diagenetic.     

On the vertical distribution of passive species in the atmospheric boundary layer

A similarity theory presented by Sorbjan (1986) is extended by taking into consideration diffusion of passive species (e.g., specific humidity) in the atmospheric boundary layer. Theoretical similarity functions are obtained for the convective and stable-continuous regimes.On leave from Institute of Environmental Engineering, Warsaw Technical University, Poland.     

Investment policy in the Polish transport sector: An appraisal

The common nature of investment policy in the Polish transport system is analysed. The transport system should contribute to national economic growth by providing an efficient service to all sections of industry, agriculture and services, and by ensuring the maintenance of a reasonable level of personal mobility through public passenger facilities. Meanwhile, as shown in the first part of the paper, the volume of transport inputs, 1970–1984 were relatively low and, moreover, their allocation among different modes of transport — not always correct. Some specific features of investment policy in the 1970s are described. Finally, the present-day phenomena and problems characteristic of Polish transport — being mainly a result of improper past policy and nowadays crisis situation — are presented. Paper presented to the IGU Working Group on Geography of Transport: Symposium No. W11, 25–29 August 1986, León, Spain.     

Some numerical urban boundary-layer studies

Two types of models, describing respectively the thermal and the dynamic structure of the urban boundary layer are presented. The influence of density and height of urban buildings, urban traffic, man-made heat flux, changes of albedo and existence of an aerosol layer are tested. The models give a possibility of explaining the influence of selected factors on the atmospheric state over an urban area.On sabbatical at Meteorological Department, University Uppsala, Sweden.     

Pricing of uncertain certified emission reductions in a Chinese coal mine methane project with an extended Rubinstein-Ståhl model

The development of coal mine methane (CMM) projects is subject to various kinds of risk, one of these being their highly variable methane content. In this study, a new methodology is proposed to reflect the impact of this uncertainty on a negotiated Certified Emission Reduction (CER) price, which is based on the available information. To simulate a process of price negotiation the Rubinstein-Ståhl bargaining game is utilized, where a buyer’s discount factor is unknown. It is assumed that a buyer’s willingness to accomplish price negotiations depends on the CER uncertainty. The bargaining model has been extended by introducing dependence of its three parameters on the probability of a failure to fulfil the contracted CER amount. To quantify this probability, we develop a conditional distribution given information on the point estimate of methane amount for the project under consideration, and on the distribution of available estimates from coal mines having similar characteristics. The proposed approach is applied to a particular CMM capture and utilization project in Anhui province, China. The results indicate that the uncertainty influence is significant, particularly when the credibility of a seller increases, i.e. the probability of a failure to fulfil the project decreases. The analysis can be of use to both negotiating parties at an early stage of a comprehensive CMM project planning.     

Uncertainty in an emissions-constrained world

Our study focuses on uncertainty in greenhouse gas (GHG) emissions from anthropogenic sources, including land use and land-use change activities. We aim to understand the relevance of diagnostic (retrospective) and prognostic (prospective) uncertainty in an emissions-temperature setting that seeks to constrain global warming and to link uncertainty consistently across temporal scales. We discuss diagnostic and prognostic uncertainty in a systems setting that allows any country to understand its national and near-term mitigation and adaptation efforts in a globally consistent and long-term context. Cumulative emissions are not only constrained and globally binding but exhibit quantitative uncertainty; and whether or not compliance with an agreed temperature target will be achieved is also uncertain. To facilitate discussions, we focus on two countries, the USA and China. While our study addresses whether or not future increase in global temperature can be kept below 2, 3, or 4 °C targets, its primary aim is to use those targets to demonstrate the relevance of both diagnostic and prognostic uncertainty. We show how to combine diagnostic and prognostic uncertainty to take more educated (precautionary) decisions for reducing emissions toward an agreed temperature target; and how to perceive combined diagnostic and prognostic uncertainty-related risk. Diagnostic uncertainty is the uncertainty contained in inventoried emission estimates and relates to the risk that true GHG emissions are greater than inventoried emission estimates reported in a specified year; prognostic uncertainty refers to cumulative emissions between a start year and a future target year, and relates to the risk that an agreed temperature target is exceeded.     

Improving Non-local Parameterization of the Convective Boundary Layer

We propose improvements in the “non-local” parameterization scheme of the convective boundary layer. The countergradient terms for components of the momentum fluxes are introduced in a form analogous to those for other scalars. The scheme also includes explicit expressions for entrainment fluxes of momentum, temperature, and humidity. A simplified procedure for calculating the boundary-layer height is proposed, consisting of two steps: the evaluation of the convection level, followed by the assessment of the depth of the interfacial layer.