|
|
Nonstationarity of the effects of modes of atmospheric circulation variability on surface climate elements
Hynčica, Martin ; Huth, Radan (advisor) ; Dobrovolný, Petr (referee) ; Beck, Christoph (referee)
Circulation modes are highly correlated, yet often distant areas detected in a field of a circulation variable, such as sea level pressure, geopotential heights, wind speed, and wind components. They consist typically of two or more action centres, which simultaneously weaken or strengthen, hence affecting the intensity and direction of atmospheric circulation and consequently surface climatic elements, such as temperature and precipitation. Temporal variability of action centres affects spatiotemporal distribution of impact on surface climatic variables. The availability of gridded datasets allows investigation of temporal behaviour of action centres and its impact on surface climatic variables on long time scales over large regions, which is, therefore, the main scientific topic of this work. Due to a large amount of reanalyses differing in e.g. assimilated type of data and model used for their calculation, the comparison of representation of circulation modes and their temporal evolution of relationships with surface climatic elements is conducted between reanalyses. Circulation modes in reanalyses assimilating both surface and upper troposphere/satellite data (ERA40, JRA-55, NCEP-1) are mostly similar whereas the 20CRv2c reanalysis, which utilizes surface data only, contains biases. Although...
|
|
|
The relationships between atmospheric circulation and surface climatic elements in Europe
Pokorná, Lucie ; Huth, Radan (advisor)
The relationships between atmospheric circulation and surface climatic elements in Europe Lucie Pokorná Abstract The variability of atmospheric circulation is the most important factor determining the changes in surface climatic elements. In this work, the relationship between atmospheric circulation and surface climatic elements like the temperature and the precipitation amounts and occurrence over the European region and some other climatic elements in central Europe is focused. The atmospheric circulation during the year is represented by modes of low-frequency circulation variability in sea level pressure (SLP) and 500-hPa heights (Z500) obtained by using statistical method "Principal component analysis". The Pearson correlation coefficient is used to describe the relationship between modes and climatic elements. Four circulation patterns in Z500 over Euro-Atlantic sector influence climate in Europe all over the year: the North Atlantic Oscillation (NAO) pattern, the East Atlantic (EA) pattern, and two Eurasian patterns (EU1, EU2). There were found patterns in SLP that strongly correlate with modes of the Z500 and influence surface climate similar way. Statistically important correlations of modes in Z500 and SLP with maximum, minimum and mean temperature, precipitation amounts and occurrence of...
|
|
|
The relationships between atmospheric circulation and surface climatic elements in Europe
Pokorná, Lucie ; Huth, Radan (advisor)
The relationships between atmospheric circulation and surface climatic elements in Europe Lucie Pokorná Abstract The variability of atmospheric circulation is the most important factor determining the changes in surface climatic elements. In this work, the relationship between atmospheric circulation and surface climatic elements like the temperature and the precipitation amounts and occurrence over the European region and some other climatic elements in central Europe is focused. The atmospheric circulation during the year is represented by modes of low-frequency circulation variability in sea level pressure (SLP) and 500-hPa heights (Z500) obtained by using statistical method "Principal component analysis". The Pearson correlation coefficient is used to describe the relationship between modes and climatic elements. Four circulation patterns in Z500 over Euro-Atlantic sector influence climate in Europe all over the year: the North Atlantic Oscillation (NAO) pattern, the East Atlantic (EA) pattern, and two Eurasian patterns (EU1, EU2). There were found patterns in SLP that strongly correlate with modes of the Z500 and influence surface climate similar way. Statistically important correlations of modes in Z500 and SLP with maximum, minimum and mean temperature, precipitation amounts and occurrence of...
|
guest ::
