The tenth IMSC, Beijing, China, 2007 - International Meetings on ...

Keywords: precipitation trend, Non-parametric methods, Mann-Kendall, Sen's Estimator Slope,
Iran
Long-range correlations of ERA-40 temperature data: Geographic patterns and height
dependence
Andrea Kiraly
Department of Physics of Complex Systems, Lorand Eotvos University, Budapest, Hungary
kiralya@lecso.elte.hu
Imre M. Janosi
Department of Physics of Complex Systems, Lorand Eotvos University, Budapest, Hungary
Global temperature data from six pressure levels (1000hPa, 850hPa, 600hPa, 400hPa,
200hPa, 100hPa) of the ERA-40 re-analisys data bank (temporal resolution of 6 hours,
covered interval of 45 years, spatial resolution of 2.5°×2.5° lat/long) are analyzed in order to
quantitatively characterize correlation properties.<strong>The</strong> method of detrended fluctuation analysis
(DFA) is exploited, which has proven useful in revealing the extent of long-range correlations
in various time series.<strong>The</strong> temperature records exhibit long-range temporal power-law
correlations extending up to several years for all grid points.<strong>The</strong> correlation exponent's
geographic distribution is quite complex at the lowermost pressure level 1000hPa, but it
reproduces the spatial patterns detected for the observational data (e.g. several thousands of
terrestrial daily temperature records from the Global Daily Climatology Network, GDCN).At
higher levels the modifying effects of the surface are weaker, the spatial distribution of
exponent values becomes much smoother. Near the equator (between 15° S and 15° N) the
level of correlations is strong, inside the 30°-60° band exhibits a local minimum and towards
the poles it becomes higher again on both hemispheres. This geographic pattern is similar to
the distributions observed for some other meteorological parameters, e.g. the correlation
exponent for ozone concentrations.<strong>The</strong>se results can serve as useful testbed for validating
globally coupled numerical ocean-atmosphere models.
Interpolation methods of weather generator parameters
Stanislava Kliegrova
Czech Hydrometeorological Institute, Czech Republic
stanislava.kliegrova@chmi.cz
Martin Dubrovsky
Institute of Atmospheric Physics, Czech Republic
Ladislav Metelka
Czech Hydrometeorological Institute, Czech Republic
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