Search

In the present study, the introduction of the Innovative Polygon Trend Analysis (IPTA), a non-parametric trend analysis methodology, is proposed as an alternative to the classical trend analysis methodology, according to which processes (normality, independence, and pre-whitening) are not necessary. Monthly precipitation measurements from Thessaloniki are analysed for the period 1971-2020, subdivided into two consecutive equal periods, to identify inherent trends among months and seasons, respectively. A finer interpretation of trends, with physical and numerical explanations and inferences, leads to the obtained results; the total monthly and seasonal precipitation values, their associated standard deviations, as well as trend slopes and trend lengths, are depicted. Increasing trends between the two sub-periods are identified for most months: winter and autumn. [ABSTRACT FROM AUTHOR]

During the last few years, extremely high temperatures have been recorded in many Greek regions and, in some cases, have been rather abnormal for each season. These extreme events appear to be persistent in duration and are occurring at a disconcerting frequency. The main objective of this study is to examine the exceptionally high temperatures that were recorded during January 2023 in Thessaloniki, Greece. The entire month was characterized by minimum and maximum temperatures that exceeded the climatological mean (1961-2000) by about 4.2 °C on average. Additionally, the average deviation for the mean maximum temperature of the month was calculated at 3.5 °C. In an attempt to classify the intensity of this possible extreme event compared to a future intermediate emission scenario (RCP4.5), a comparison of the observational data with the corresponding data from two future projections (2041-2060 and 2081-2100) of a high-resolution regional climate model was carried out. The spatial resolution of the simulations was 10 x 10 km and they were the result of the dynamical downscaling of the RegCM regional climate model after nesting a 25 km simulation of the model for the initial and boundary conditions. Finally, through this study, the contribution of the synoptic-scale atmospheric conditions of this event was examined. [ABSTRACT FROM AUTHOR]

In this work, data from ten (10) meteorological stations in various areas of Thessaloniki, Greece were used in order the cooling and heating degree days for each station to be calculated. The specific data were applied to a detached house for each of the ten areas considered. Furthermore, an analysis of the thermal insulation adequacy of the single family house that has been selected with the necessary methodology and the necessary sketches was conducted in order to have the illustration of the building. The study was divided into two cases, where the first refers to a typical thermal insulation that characterizes a building of the territory of Greece, and the second case where the residence has undergone a radical renovation of its thermal insulation. Results show that three different climatic zones appear in the same region instead of one. [ABSTRACT FROM AUTHOR]

The present study estimates the future impact of climate change on heat-related mortality in Thessaloniki, Greece. Mortality attributed to high temperatures will increase from 0.64% (95% eCI = -1.12, 2.48) to 3.32% (95% eCI: 0.52, 6.1), whereas cold-related mortality will be reduced from 0.7% (95% eCI = -2.24, 3.31) to 0.37% (95% eCI = -1.63, 2.2). Overall, the excess total mortality attributed to temperature will be increased by 2.33% in the future. Among the elderly, high temperatures will cause 5.14% of deaths, highlighting their increased vulnerability. These findings emphasize the urgent need for targeted public health planning, mitigation, and adaptation strategies to address the health effects of climate change. [ABSTRACT FROM AUTHOR]

The aerosol species separation algorithm (ASSA) is a method designed to retrieve vertical concentration profiles of individual aerosol species by combining measurements from lidar systems and spectrophotometers. The ASSA operates as a forward model, simulating as the first step the attenuated backscatter and volume depolarization ratios at various wavelengths initially measured by lidar systems. Subsequently, it extends these simulations to reproduce radiance spectra obtained from co-located spectrophotometers by integrating a radiative transfer model. Currently, the ASSA relies on a lookup table (LUT) of intensive aerosol properties that correspond to mixtures generated from up to eight pure aerosol species as these are defined in the OPAC database. In this study we are focusing on the first step and investigating the performance of the algorithm when solely fitting nighttime data from the Thessaloniki lidar system are used. The algorithm identifies the ensemble of mixture/mass concentration combinations that best fit the elastic and Raman 4 primary species attenuated backscatter and depolarization ratio profiles. [ABSTRACT FROM AUTHOR]

The monitoring of trace gases in the troposphere has been routinely performed at the Laboratory of Atmospheric Physics, Thessaloniki, Greece, for a decade now, by multiple Multi-Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) instruments. Even though measurements of trace gas concentrations in the troposphere are of great interest in terms of air quality, the MAX-DOAS technique is only sensitive to absorbers in the lowest few kilometers of the atmosphere. In this work, we present a methodology for the retrieval of total NO2 columns in the atmosphere by applying the DOAS technique on direct sun spectra (DS-DOAS) measured with a new research-grade system. The advantages and limitations of the total NO2 retrieval methodology, based on DS-DOAS, are discussed. The accuracy and the quality of the retrieved columns were assessed by comparison with a collocated Pandora system that also measures total NO2 column amounts using a similar technique with independent calibration. [ABSTRACT FROM AUTHOR]