Geofizika, Vol. 21 No. 1, 2004.
Izvorni znanstveni članak
Analysis of Zagreb climatological data series using empirically decomposed intrinsic mode functions
Valentina Radić
Zoran Pasarić
Nadežda Šinik
Sažetak
The empirical mode decomposition method (EMD) (Huang, 1998) is applied
to the series of annual and seasonal averages of temperature, cloudiness,
air pressure and annual and seasonal sums of global radiation and precipitation,
all observed in Zagreb-Gri~ in the period 1862–2002. The method
itself decomposes the original series into so called intrincic mode functions
(IMF), each being characterized by its own, intrinsic time scale.
Sums of the low-frequency IMFs for the single element revealed present
climatic fluctuations on the decade-to-century scale. It is confirmed that
climatic fluctuations of every single element, particularly temperature and
cloudiness, are the results of variations in the global atmospheric circulation
above the whole Europe. Trend and long-term variations of Zagreb temperature
fits to globally observed increase of temperature but also to variations
of zonal circulation index. Exchange of Hadley’s zonal and Rossby’s wave regime
of the general atmospheric circulation at the beginning of the 20th century
is observed in the long-term variations of almost every element. Linear
correlation coefficients between annual and seasonal long-term variations
are calculated. It is shown that spring and winter variations mostly influenced
annual fluctuations that is due to internal feed-back processes.
Also, correlation coefficients for every pair of climatic element are calculated,
enabling conclusions about interaction between elements on long-term
scales.
Ključne riječi
empirical mode decomposition; intrinsic mode functions; climatological series; climatic fluctuations; Zagreb
Hrčak ID:
17006
URI
Datum izdavanja:
15.12.2004.
Posjeta: 1.258 *