. This report addresses the effects of pollution on the development of precipitation in clean ("pristine") and polluted ("hazy") environments in the Eastern Mediterranean by using the Integrated Community Limited Area Modeling System (ICLAMS) (an extended version of the Regional Atmospheric Modeling System, RAMS). The use of this model allows one to investigate the interactions of the aerosols with cloud development. The simulations show that the onset of precipitation in hazy clouds is delayed compared to pristine conditions. Adding small concentrations of GCCN to polluted clouds promotes early-stage rain. The addition of GCCN to pristine clouds has no effect on precipitation amounts. Topography was found to be more important for the distribution of precipitation than aerosol properties. Increasing by 15% the concentration of hygroscopic dust particles for a case study over the Eastern Mediterranean resulted in more vigorous convection and more intense updrafts. The clouds that were formed extended about three kilometers higher, delaying the initiation of precipitation by one hour. Prognostic treatment of the aerosol concentrations in the explicit cloud droplet nucleation scheme of the model, improved the model performance for the twenty-four hour accumulated precipitation. The spatial distribution and the amounts of precipitation were found to vary greatly between the different aerosol scenarios. These results indicate the large uncertainty that remains and the need for more accurate description of aerosol feedbacks in atmospheric models and climate change predictions.

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An integrated modeling study on the effects of mineral dust and sea salt particles on clouds and precipitation

Daylight factor estimation at an early design stage to reduce buildings' energy consumption due to artificial lighting: A numerical approach based on Doehlert and Box–Behnken designs

Development of polynomial regression models for composite dynamic envelopes’ thermal performance forecasting

Study of coupled transient radiation-natural convection heat transfer across rectangular cavities in the vicinity of low emissivity thin films for innovative building envelope applications

In this study, copper (II) ion reduction was investigated using a four-factor three-level Box–Behnken statistical experimental design (BBD) under different adsorption conditions, such as initial concentration, cotton seed cake dose, pH and temperature. Optimum conditions for maximizing the copper (II) reduction were determined using Derringer's desired function methodology and were found to be an initial concentration of 300 mg/l, cotton seed cake dose of 1 g/l, pH of 7, and a temperature of 50 °C. Under optimum conditions, copper (II) reduction was found to be 88% with a desirability value of 0.982. The suitability of the predicted optimum conditions was validated using experimental data. The Langmuir isotherm model clearly explains the copper (II) adsorption on the cotton seed cake. The best fit of the kinetic model was found to be a pseudo first order rate equation. Finally, the characteristics of the cotton seed cake were analyzed using FTIR, XPS and SEM with EDS.

An eco-friendly approach for copper (II) ion adsorption onto cotton seed cake and its characterization: Simulation and validation

A three-dimensional numerical model (Regional Atmospheric Modeling System—-RAMS) was used to study the formation and evolution of water forms in a two-layer cloud structure observed during a field campaign over Brest (France). The model performance in regular operations, using conventional meteorological data as initial and lateral boundary conditions, was also examined. Remote sensing observations of the cloud system and in-situ aircraft data, selected during the campaign, were used to validate the model outputs. The model simulations showed that the lower cloud formation was characterized by high number concentration of pristine ice and snow, while the concentration of aggregates, graupel and hail were considerably lower. Hydrometeors in liquid phase appeared demonstrating high number concentration and water content on the top of this layer. The upper cloud layer consisted only of frozen water substances in lower amounts. The qualitative and quantitative comparison of the model-calculated meteorological and microphysical fields to the available observational data revealed that the model reflected fairly well the cloud structure (e.g., the spatio-temporal variability of the cloud parameters, the geometry of the cloud system). However, there were deviations as far as the model underestimating the ice water content (IWC) and number concentration (Nt) fields is concerned, especially at the atmospheric layer between 2.5 and 4 km of altitude. These deviations of the model simulated quantities from the measured ones may be attributed either to the performance of the model’s microphysics scheme, to instrument inaccuracies and to the local disturbance caused by the aircraft.

Theodoros I. Lekas

Papers

Analysis of a two-layer cloud system with RAMS model and comparison to airborne observations