Scaling behaviour of the global tropopause C. Varotsos, M. Efstathiou, and C. Tzanis Department of Applied Physics, University of Athens, Athens, Greece
Abstract. Detrended fluctuation analysis is applied to the time series of the global
tropopause height derived from the 1980–2004 daily radiosonde data, in
order to detect long-range correlations in its time evolution.
Global tropopause height fluctuations in small time-intervals are found to
be positively correlated to those in larger time intervals in a power-law
fashion. The exponent of this dependence is larger in the tropics than in
the middle and high latitudes in both hemispheres. Greater persistence is
observed in the tropopause of the Northern than in the Southern Hemisphere.
A plausible physical explanation of the fact that long-range correlations in
tropopause variability decreases with increasing latitude is that the column
ozone fluctuations (that are closely related with the tropopause ones)
exhibit long range correlations, which are larger in tropics than in the
middle and high latitudes at long time scales.
This finding for the tropopause height variability should reduce the
existing uncertainties in assessing the climatic characteristics. More
specifically the reliably modelled values of a climatic variable (i.e. past
and future simulations) must exhibit the same scaling behaviour with that
possibly existing in the real observations of the variable under
consideration. An effort has been made to this end by applying the detrended
fluctuation analysis to the global mean monthly land and sea surface
temperature anomalies during the period January 1850–August 2008. The result obtained
supports the findings presented above, notably: the correlations between the
fluctuations in the global mean monthly land and sea surface temperature
display scaling behaviour which must characterizes any projection.
Citation: Varotsos, C., Efstathiou, M., and Tzanis, C.: Scaling behaviour of the global tropopause, Atmos. Chem. Phys., 9, 677-683, doi:10.5194/acp-9-677-2009, 2009.