Relationship Between Land Surface Temperature and Imperviousness Density in The Urban Area of Iasi.

This study aims to quantify the relationship between Land Surface Temperature (LST) and Imperviousness Density (IMD) in Iași. This was done through linear regression analysis which involves quantifying the relationship between one independent variable (explanatory, predictor) and one dependent variable (response). Thus, in our study, the dependent variable is represented by the LST product obtained through MODIS sensors in the period 2014-2018, while the independent variable is represented by IMD. The coefficient of determination (R2) obtained, higher than 0.5 for most of the year, indicates a statistically significant relationship between LST and IMD. The highest values of R2 are identified during the day spring and summer seasons. Thus, 70% and respectively 80% of the spatial variation of LST is explained by the distribution of IMD during these two seasons and the regression coefficients indicate, on the one hand, that the relationship between the two variables is a direct one (LST values increase at the same time with IMD values), and on the other hand, that the increase of LST corresponds to a gradient between 0.3-0.6 oC per 10% IMD. During the day, the lowest values of R2 appear in autumn and winter seasons, as a result of the local topography that facilitates the frequency of thermal inversions in this period of the year. On the other hand, during the night, R2 has values between 0.40 and 0.60, with the lowest values in the autumn season and the highest in the spring season, respectively

The Influence of Urban Climate on Bioclimatic Conditions in the City of Iași, Romania

This study was carried out in order to outline the human bioclimatic stress/comfort conditions within the area of Iași city, Romania. The meteorological data were obtained over a 7-year period (December 2012–November 2019) from an observation network relying on 8 fixed observation points located in selected spots, relevant for the urban climate conditions in the region. The results demonstrate firstly that throughout the entire analyzed period, using the thermo-hygrometric index (THI), “very cold” conditions characterize 4% of the entire year in the inner parts of the city and 6% in the rural area, while the “hot” THI conditions vary from 18% in the middle of the urban heat island to 15% in the rural area. Overall, the rural areas are generally more comfortable than the inner city, especially during summer, when the urban heat island (UHI) core is starting to develop from the evening and persists during the night. On the contrary, the UHI renders the inner city more comfortable than the rural surroundings from October to April. Similar bioclimatic conditions are also presented in detail for the summer by the relative strain index (RSI), which exceeds the stress threshold value mostly during heat waves, when a significant contrast between urban and rural areas is felt. In brief, it has been determined that the most suitable area for human comfort in Iași city is inside the urban area during the winter and in the rural areas during the summer

Three Years of Observations on Global Solar Radiation at Mădârjac Weather Station (270 m) - Central Moldavian Plateau

This study is based on 3 years of hourly observations of global solar radiation (2014-2016), at a new weather station installed in the region of Central Moldavian Plateau, at Mădârjac (47.05°N, 27.25°E, 270 m). The main characteristics of annual, monthly and daily regime of global radiation were emphasized using for comparison similar data from Iașioficial weather station. Smaller annual amount of global solar radiation than those observed in previous studies were observed, reaching 4734 MJ/m2 in Iași and 4454 MJ/m2 in Mădârjac. An altidudinal gradient of global solar radiation close to 140 MJ/m2 was identified for the hilly region of Moldova. Despite the overall higher values in Iași, 30% of days indicates higher values of this parameter at Mădârjac weather station. These results can be used for the evaluation of the photo-voltaic potential in the region, but also to understand the altitudinal differences of solar radiation in the hilly region in Moldavia, since the only long-range actinometric stations from this part of Romania, Iași and Galați, are located at low altitudes

PRECURSOR WEATHER CONDITIONS FOR HAIL-EVENT FORECASTING IN THE MOLDAVIA

he present work analysed a statistically representative number of severe convective events which caused hail and material damage during 1990-2015. For these episodes heights of 0oC, -6oC, -10oC and -20oC isotherms were analyzed. In the layers between these four isotherms, the formation and growth of hailstones occur. The height of these isotherms in the period preceding hail is essential in weather forecast of this phenomenon. Lifted index values recorded before hail events are also correlated with height isotherms. The altitudinal differences between the height of -6oC and -20oC isotherm and freezing level which represents intervals of initiation and formation of hail are identified. Not at last the values of the meteorological indices used to forecast the potential formation and hail falling in extracarpathian Moldavia are presented in details

Synoptic Conditions Generating Heat Waves and Warm Spells in Romania

Heat waves and warm spells are extreme meteorological events that generate a significant number of casualties in temperate regions, as well as outside of temperate regions. For the purpose of this paper, heat waves and warm spells were identified based on daily maximum temperatures recorded at 27 weather stations located in Romania over a 55-year period (1961–2015). The intensity threshold was the 90th percentile, and the length of an event was of minimum three consecutive days. We analyzed 111 heat wave and warm spell events totaling 423 days. The classification of synoptic conditions was based on daily reanalysis at three geopotential levels and on the online version of a backward trajectories model. The main findings are that there are two major types of genetic conditions. These were identified as: (i) radiative heat waves and warm spells (type A) generated by warming the air mass due to high amounts of radiation which was found dominant in warm season; and (ii) advective heat waves and warm spells (type B) generated mainly by warm air mass advection which prevails in winter and transition seasons. These major types consist of two and three sub-types, respectively. The results could become a useful tool for weather forecasters in order to better predict the occurrence of heat waves and warm spells

Cotnari vineyard - a gift of hydraulic foehn?

Cotnari vineyard is the northernmost wine-growing vineyard of our country, located close enough to the northern limit of the expanding region of the grape vine. Within this study, we analyse one of the climatic factors that, in our view, contributes to the climatic favorability of this region for the vine plantations: the foehn. More precisely, the hydraulic foehn, which is not mentioned in the Romanian climatology literature, although the mechanism associated with the development of this type of foehn wind, is described for more than 40 years in the international climatological literature. We bring arguments for the manifestation of the hydraulic foehn during winter 2013-2014 in the related region of Cotnary vineyard on the basis of measurements accomplished at Paşcani climatologic station and at other 11 points of hourly monitoring temperature of Dealu Mare-Hârlău region. Additionally, radio-sounding data, synoptic maps and other synoptic data of some of the meteorological indicators of foehn development are used. Local generating mechanism, periods of occurrence, synoptic conditions associated to its generation, the intensity of temperature difference recorded within the region and the possible effect of its development in the increase of the region’s favourability for the vine-growing, are analysed in our stud

Weather Influence on Native and Alien Mantis Dynamics and Their Abundance in the Current Climate Change Conditions

Humans have traded and transported alien species for millennia, both with and without intention to spread them to new areas. Consistent knowledge of their ecology will allow decision makers to take suitable conservation actions, with the aim of avoiding threatening native species. Praying mantids (Mantodea) are predatory insects with a high impact on local invertebrates’ fauna. An alien mantis species (Hierodula tenuidentata) could create a disequilibrium in both the local ecosystem and in autochthonous mantid species (Mantis religiosa) if it can adapt to the local ecological conditions. Through this study, we reveal that the number of Hierodula tenuidentata individuals from an Eastern European Natura 2000 site was 7.6 times higher than the number of Mantis religiosa suggesting a higher density of the allochthonous species in the study area. According to a GLM analysis, the population of Mantis religiosa, measured from August to the end of October, declines more rapidly and is negatively influenced by the number of days from the first day of the year, while the population of Hierodula tenuidentata is influenced by local weather factors. This is the first study which analyzes the influence of local weather factors (namely air temperature, precipitation, daily atmospheric pressure, daily wind direction and speed, daily cloud cover, sunshine duration and number of days from the first day of the year) on the abundance dynamic of mantises in order to understand their ecology in the current climate change influence

Weather Influence on Native and Alien Mantis Dynamics and Their Abundance in the Current Climate Change Conditions

Humans have traded and transported alien species for millennia, both with and without intention to spread them to new areas. Consistent knowledge of their ecology will allow decision makers to take suitable conservation actions, with the aim of avoiding threatening native species. Praying mantids (Mantodea) are predatory insects with a high impact on local invertebrates’ fauna. An alien mantis species (Hierodula tenuidentata) could create a disequilibrium in both the local ecosystem and in autochthonous mantid species (Mantis religiosa) if it can adapt to the local ecological conditions. Through this study, we reveal that the number of Hierodula tenuidentata individuals from an Eastern European Natura 2000 site was 7.6 times higher than the number of Mantis religiosa suggesting a higher density of the allochthonous species in the study area. According to a GLM analysis, the population of Mantis religiosa, measured from August to the end of October, declines more rapidly and is negatively influenced by the number of days from the first day of the year, while the population of Hierodula tenuidentata is influenced by local weather factors. This is the first study which analyzes the influence of local weather factors (namely air temperature, precipitation, daily atmospheric pressure, daily wind direction and speed, daily cloud cover, sunshine duration and number of days from the first day of the year) on the abundance dynamic of mantises in order to understand their ecology in the current climate change influence