Search

In this work, artificial neural networks (ANNs) were developed and applied in order to forecast the discomfort levels due to the combination of high temperature and air humidity, during the hot season of the year, in eight different regions within the Greater Athens area (GAA), Greece. For the selection of the best type and architecture of ANNs-forecasting models, the multiple criteria analysis (MCA) technique was applied. Three different types of ANNs were developed and tested with the MCA method. Concretely, the multilayer perceptron, the generalized feed forward networks (GFFN), and the time-lag recurrent networks were developed and tested. Results showed that the best ANNs type performance was achieved by using the GFFN model for the prediction of discomfort levels due to high temperature and air humidity within GAA. For the evaluation of the constructed ANNs, appropriate statistical indices were used. The analysis proved that the forecasting ability of the developed ANNs models is very satisfactory at a significant statistical level of p < 0.01. [ABSTRACT FROM AUTHOR]

The relationships between smoke concentrations, measured at two monitoring stations in Athens by the ASTM (American Society for Testing and Materials) and the OECD (Organization for Economic Co-Operation and Development) methods are studied by using a sample of 738 mean daily values of simultaneous measurements during the period 1984-1986. It is shown that an exponential model, different for each monitoring station, with smoke concentrations in COH (coefficient of haze) as the independent variable and smoke concentrations in μgr/m as the dependent variable, was the most appropriate for transforming smoke data from COH to μgr/m. Also it is shown that the transformation models can be applied independent of the prevailing meteorological conditions. Finally some tentative conclusions are derived concerning the long term variations of smoke concentrations in μgr/m for the period 1977-1990 and 1973-1990 at the two monitoring stations respectively. The trend analysis has shown that pollution abatement efforts resulted in an about 10% per year decreasing trend in smoke concentrations, during the period 1986-1990, at these two Athenian stations. [ABSTRACT FROM AUTHOR]

Copyright of Theoretical & Applied Climatology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Theoretical & Applied Climatology is the property of Springer Nature and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)