Articolele autorului Sorin Cheval
Link la profilul stiintific al lui Sorin Cheval

The summer surface urban heat island of Bucharest (Romania) retrieved from MODIS images

The summer surface urban heat island (SUHI) of the city of Bucharest (Romania) is investigated in terms of its shape, intensity, extension and links to land cover. The study employs land surface temperature (LST) data retrieved by the Moderate Resolution Imaging Spectroradiometer (MODIS) sensors aboard the Terra (EOS AM-1) and Aqua (EOS PM-1) NASA satellites, between 2000 and 2012. Based on the Rodionov regime shift index, the significant changing

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Spatiotemporal variability of meteorological drought in Romania using the standardized precipitation index (SPI)

This study addresses the spatial and temporal variability of meteorological drought in Romania based on a standardized precipitation index (SPI) analysis over the period 1961-2010. The 1- and 3 mo SPI values from 124 meteorological stations were used to examine the duration, magnitude, intensity, and frequency of the drought spells. Empirical orthogonal function analysis supported the investigations on the variability of the SPI values both in time

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Changes in annual temperature extremes in the Carpathians since AD 1961

The Carpathian Mountains region cover areas from seven countries of central and southeastern Europe, the mountain chain having major regional influences on the temperate climate, specific to latitudes between 43°N and 49°N. In order to identify changes in the annual temperature extremes, the Mann–Kendall nonparametric trend test has been applied to several thermal indices, recommended by the expert team on climate change detection and indices.

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Climate of the Carpathian Region in the period 1961-2010: climatologies and trends of 10 variables

The Carpathians are the longest mountain range in Europe and a geographic barrier between Central Europe, Eastern Europe, and the Balkans. To investigate the climate of the area, the CARPATCLIM project members collected, quality-checked, homogenized, harmonized, and interpolated daily data for 16 meteorological variables and many derived indicators related to the period 1961-2010. The principal outcome of the project is the Climate Atlas of the Carpathian

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Climate variability in the Carpathian Mountains region over 1961-2010

The Carpathian Mountains Region (CMR) lies over parts of the territories of seven Central and South-Eastern European countries, and the mountain chain induces major changes in the temperate climate specific to the latitudes between 43° and 49°N. Different administrations govern the long-term meteorological networks; the infrastructure, collection protocols, and storage capacities are specific to each country, so that a comprehensive study on the

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Accuracy and sensitivity analysis for 54 models of computing hourly diffuse solar irradiation on clear sky

Fifty-four broadband models for computation of solar diffuse irradiation on horizontal surface were tested in Romania (South-Eastern Europe). The input data consist of surface meteorological data, column integrated data, and data derived from satellite measurements. The testing procedure is performed in 21 stages intended to provide information about the sensitivity of the models to various sets of input data. There is no model to be ranked “the

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Accuracy analysis for fifty-four clear-sky solar radiation models using routine hourly global irradiance measurements in Romania

Fifty-four broadband clear-sky models for computation of global solar irradiance on horizontal surfaces are tested by using measured data from Romania (South-Eastern Europe). The input data to the models consist of surface meteorological data, column integrated data and data derived from satellite measurements. The testing procedure is performed in twenty-one steps for two different sites in Romania. The models accuracy is reported for various sets

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Comparison Between Radar Estimated and Rain Gauge Measured Precipitation in the Moldavian Plateau

Heavy rainfall events have produced significant damages and casualties in the Moldavian Plateau (Romania) in the last decades. Such phenomena are characterized by large spatial and temporal variations, and the forecast of their occurrence is thus very challenging. This study aims to compare the radar estimations and the rain gauge measurements, in order to improve the quantitative precipitation estimation (QPE) in the area of interest. The research

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Computing global and diffuse solar hourly irradiation on clear sky. Review and testing of 54 models

Fifty-four broad band models for computation of global and diffuse irradiance on horizontal surface are shortly presented and tested. The input data for these models consist of surface meteorological data, atmospheric column integrated data and data derived from satellite measurements. The testing procedure is performed for two meteorological stations in Romania (South-Eastern Europe). The testing procedure consists of forty-two stages intended to

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Benchmarking homogenization algorithms for monthly data

The COST (European Cooperation in Science and Technology) Action ES0601: advances in homogenization methods of climate series: an integrated approach (HOME) has executed a blind intercomparison and validation study for monthly homogenization algorithms. Time series of monthly temperature and precipitation were evaluated because of their importance for climate studies and because they represent two important types of statistics (additive and multiplicative).

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