A. Kamoutsis

AIR TEMPERATURE AND THERMAL COMFORT CONDITIONS IN MOUNTAINOUS AND URBAN REGIONS

The present study explored air temperature and thermal comfort conditions in mountainous region of Nafpaktia (Municipality of Apodotia, Prefecture of Aitoloakarnania), a region without important commercial, industrial or other activities in west continental Greece, and in Athens, a metropolitan urban center in southeast continental Greece. There were 11 study sites in the case of Nafpaktia (676–1455 m altitude), areas with different altitude, ground cover, plant species and plant density. There was one study site in Athens (30 m altitude) nearby a densely built area, under the pressure of industrial activities and heavy traffic. Air temperature and humidity, 1.5 m above ground surface, were monitored simultaneously every 15 min in each site for the period between 1 July and 31 August 2006. Air temperature and relative humidity data were used for the calculation of the thermohygrometric index (THI) from which thermal comfort conditions were evaluated. For this work, two sites of mountainous Nafpaktia region (MNR), one characterized by the lower (fir and chestnut forest area) and the other by the higher (Evinos River area) average THI value, are presented. Results showed that MNR provided clearly improved air temperature and thermal comfort conditions in comparison to Athens in the study period. Fir and chestnut forest area was more beneficial, from a bioclimatological point of view, compared to Evinos River area. Therefore, fir and chestnut forest area should be further supported as a reliable alternative tourist destination for rest and recreation.

An Application of Parametric and Nonparametric Models to the Assessment of Fluoride Levels in Vegetation Exposed to Stack Emissions of an Aluminum Reduction Plant in Greece

Abstract Various statistical models were developed for assessing airborne fluoride (F) levels in natural vegetation near an aluminum reduction plant using as predictor variables the distance from the emission source, the predominating wind, and characteristic topography-geomorphology parameters. Results revealed that F concentrations in vegetation showed a predictable response to both wind conditions and landscape features. The linear model was found to give good estimations, taking advantage of the relatively strong linear correlation between concentration and distance. A nonlinear relationship between the F concentration in vegetation and the other variables was also found, while interactions between the variables were found to be non-first-order. The nonlinear relationship hypothesis was supported by the improved results of various nonlinear models that also indicated the importance of the area’s topography-geomorphology and meteorology in model predictions. The application of an artificial neural network (ANN) model showed the closest agreement between predicted and observed values with a correlation coefficient of 0.92. The improved reliability of the ANN and a regression tree model (RTM) also were indicated by the normal distribution of their residuals. The RTM and the ANN were further investigated and found to be capable of identifying the importance of the variables in vegetation exposure to air emissions.

Biometeorological Conditions in the Urban Park of Nea Smirni in the Greater Region of Athens, Greece During Summer

The aim of this study was to investigate the biometeorological environment in relation with different types of ground cover in the urban park area of Nea Smirni in the greater region of Athens in Greece. Five sites were selected, including irrigated (IPS) and non irrigated plant species (NIPS) and the adjacent build-up area (ABA). The thermal condition of the environment around the examined sites was evaluated using an infrared thermografic camera in the summer of the years 2009–2011. Also, data loggers with temperature and humidity sensors were placed in the aforementioned sites during the experimental period. Results showed that the environment of NIPS appeared, in general, to have a warmer trees foliage in relation to IPS by about 2°C. Higher surface temperature conditions were detected in sites covered with structural materials. On the other hand, lower temperature conditions were observed in the shaded sites and in the water surfaces. For the period between 11:00 and 19:00 h, more favorable human thermal comfort conditions among the examined types of ground cover, as were evaluated by the thermohygrometric index, were observed at the environment with IPS, especially in July, rendering the aforementioned environment more friendly to the visitors.

Air Temperature Estimation by Using Artificial Neural NetworkModels in the Greater Athens Area, Greece

Air temperature (T) data were estimated in the regions of Nea Smirni, Penteli, and Peristeri, in the greater Athens area, Greece, using the T data of a reference station in Penteli. Two artificial neural network approaches were developed. The first approach, MLP1, used the T as input parameter and the second, MLP2, used additionally the time of the corresponding T. One site in Nea Smirni, three sites in Penteli, from which two are located in the Pentelikon mountain, and one site in Peristeri were selected based on different land use and altitude. T data were monitored in each site for the period between December 1, 2009, and November 30, 2010. In this work the two extreme seasons (winter and summer) are presented. The results showed that the MLP2 model was better (higher and lower MAE) than MLP1 for the T estimation in both winter and summer, independently of the examined region. In general, MLP1 and MLP2 models provided more accurate T estimations in regions located in greater distance (Nea Smirni and Peristeri) from the reference station in relation to the nearby Pentelikon mountain. The greater distance T estimations, in most cases, were better in winter compared to summer.

Studies on the Growth of Lantana camara L. subsp. camara in Relation to Glasshouse Environment and Paclobutrazol

The effects of environmental factors and the plant growth regulator paclobutrazol on Lantana camara L. subsp. camara plants were investigated under glasshouse conditions in Attica, Greece during June to November 1997 and 1998. Lantana plants were grown at two shading levels (0 and 66% shading) and treated with paclobutrazol (0, 50, 100 and 200 mg/l) foliar sprays after pinching. The cumulated function was used to detect several trends in environmental (photosynthetically active radiation, air temperature, relative humidity) and biometrical (growth index) data. Results showed that the general increase trend of the growth index (GI) of the non-treated plants coincided, in general, with the trends of variation of the environmental data at the two shading levels, while for the plants treated with paclobutrazol at 50 mg/l, the trend depended on shading level and followed approximately the trends of the environmental data. The trends of GI increase of the plants treated with 100 and 200 mg/l paclobutrazol showed an earlier onset of decline in comparison to the non-treated plants at the two shading levels.

Air Temperature Estimation Over the Ainos Mountain, Kefallinia Island Using Linear Regression Analysis

Mountain Ainos is the highest mountain of the Ionian Islands with a maximum elevation of 1628 m. Its National Park is characterized by rich flora including endemic species such as Greek fir. In order to exploit fully its touristic potential, it is necessary to examine the mountain climate. However in situ measurements of climatic parameters in mountain areas pose difficulties as far as to access areas of interest. The current study addresses one specific object: Estimating the air temperature at different altitudes of the southeastern side of Mt. Ainos, having air temperature data at the exact same altitudes of the northwestern side which is more easily accessible. We performed linear regression analysis to estimate the mean, maximum and minimum daily air temperature of the southeastern sites from data measured at the northwestern one. The results are considered satisfactory in air temperature estimation at all examined altitudes. More accurate estimations were provided in the case of the mean air temperature at the altitude of 1580 m. Also, linear models indicated noticeable estimations of the minimum temperatures at 1300 and 1580 m.

Statistical Models in Estimating Air Temperature in a Mountainous Region of Greece

The current work focuses on the estimation of air temperature (T) conditions in two high altitude (alt) sites (1580 m), each one at different orientation (southeast and northwest) in the mountain (Mt) Aenos in the island of Cephalonia, Greece, by using two well-known statistical models, simple linear regression (SLR) and multi-layer perceptron ( MLP), one of the most commonly used artificial neural networks. More specifically, the estimation of mean, maximum and minimum T in high alt sites was based on the respective T data of two lower alt sites (1100 m), the first at southeast and the second at northwest orientations, and was carried out separately for each orientation. The performance of both SLR and MLP models was evaluated by the coefficient of determination (R2) and the Mean Absolute Error (MAE). Results showed that the examined models (SLR and MLP) provided very satisfactory results with regard to the estimation of mean, maximum and minimum T, regarding southeast orientation (R2 ranging from 0.96 to 0.98), with mean T estimation being relatively better, as confirmed by the lowest MAE (0.83). Regarding northwest orientation, T estimation was less accurate (lower R2 and higher MAE), compared to the respective estimation of southeast orientation, but, the results were considered adequate (R2 and MAE ranging from 0.88 to 0.92 and 1.00 to 1.40, respectively). In general, the estimations of the mean T were better than those of the extreme ones (minimum and maximum T). In addition, better results (higher R2 and lower, in general, MAE) were obtained when T estimations were based on T data derived from sites located at areas with similar surroundings, as in the case of dense and tall vegetation of the sites at southeast orientation, irrespective of applied method. Current World Environment Journal Website: www.cwejournal.org ISSN: 0973-4929, Vol. 12, No. (3) 2017, Pg. 547-552 CONTACT Kostas Chronopoulos kchrono@aua.gr Department of Biotechnology, Agricultural University of Athens, Iera Odos 75, Athens 11855, Greece.

Phenological Response of Pear and Orange Trees to Air Temperature at Regions of Thessaly and Peloponnesus, Greece

This research assessed the phenological response of pear (Pyrus communis L. cv. Krystalli) and of orange (Citrus sinensis L. cv. Washington Navel) trees to air temperature at the regions of Kato Lechonia in Thessaly and at Agiorgitika, Ligourio and Amycles in Peloponnesus, Greece. Phenological observations took place in order to evaluate the start dates of various phenophases of the studied cultivars, from the “end of bud swelling” to the “fruit development” stages. Also, air temperature data were monitored from meteorological stations located near the experimental orchards. The results showed that the warmer conditions at Kato Lechonia in comparison with those of Agiorgitika caused an earlier appearance of pear tree phenophases. The timing of the “end of bud swelling” at Kato Lechonia and Agiorgitika correlated negatively with the air temperature of the late winter (February) as did the timing of “bud burst” and of “appearance of flower buds” at Kato Lechonia. As regards to the orange tree, similar phenological behavior during the examined period was observed between the regions of Ligourio and Amycles due to their “similar” thermal conditions.