Wind Speed and Temperature Variations in Burgas Region Since 1836

Abstract

AbstractThe global wind speeds vary in time. They had been decreasing for several decades, starting in the 1970s and they are getting faster during the last decades. The Intergovernmental Panel on Climate Change states that “there is evidence for long-term changes in the large-scale atmospheric circulation, such as a poleward shift and strengthening of the westerly winds” and that these observed changes likely will continue. The wind speed variations are important in the field of renewable energy sources. Other application of wind variation study is the influence of winds on air quality in urban areas. Recently new time series of wind data have been created in 20th Century Reanalysis Version 3 data provided by the National Oceanic and Atmospheric Administration / Oceanic and Atmospheric Research / Earth System Research Laboratories - Physical Sciences Laboratory, Boulder, Colorado, USA. The 20th Century Reanalysis Version 3 data set cover large time period (1836–2016) globally gridded data set that represents several Earth's atmosphere parameters. Time series of air temperature, U- and V- components of winds over Burgas for the trapezoid 43-44N, 27-28E are extracted from the gridded data, and next, time series of wind speed is calculated. The variations of air temperature and wind speed are analyzed and compared with the cycles of solar activity, represented by the Index of Total Solar Irradiance (TSI). The spectra of wind oscillations are determined by Fast Fourier Transform (FFT). The common solar-climate cycles are separated from time series by the Method of Partial Fourier Approximation (PFA). These cycles are from 16 narrow frequency bands, whose periods are between 5 and 180 years. Their superposition may help long-term forecasts and better understanding of solar influence on atmospheric circulation over South-Eastern part of Bulgaria.KeywordsClimate changeWindTemperatureTSI