ELFT HÍRADÓ

[StatFizSzeminar <statfiz AT glu.elte.hu>]

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           ELTE TTK Fizikai Intézet
       STATISZTIKUS FIZIKAI SZEMINÁRIUM


             2019. október 16.

                   szerda 

                   11.00

                Ksenia Guseva

        Carl von Ossietzky University

"The effect of intermittent upwelling 
     events on plankton blooms"

The larger scale the ocean's hydrodynamic
flow is characterized by the presence of 
large eddies (vortices), which play a very
important role in phytoplankton ecosystems.
Another important large scale phenomenon is
upwelling, which brings a load of nutrients
to the surface, sometimes triggering algal 
blooms. We investigate the effect of inter-
mittent upwelling on the biological community
in the presence of large eddies formed in the
wake of an island. We use a theoretical model
of this system by coupling a kinematic flow
field to a population dynamical model for 
plankton growth. We observe plankton blooms 
when nutrients are trapped by vortices, and 
analyse how this dynamics depends on the 
timing and intensity of upwelling events.



                   11.45

                Gábor Drótos


 University of the Balearic Islands and CSIC


"What the snapshot/pullback attractor of an 
Earth system model can tell about climate 
change: a case study about the ENSO--Indian
       monsoon  teleconnection"



The climate of a time instant under expli-
citly time-dependent forcing  seems to be 
most plausibly defined by the natural 
probability measure of  the corresponding 
snapshot attractor, and climate change is 
described by the time evolution of this 
probability measure. This probability measure 
is numerically represented by an ensemble
of trajectories (realizations)  emanating
from different initial conditions, but only
after memory loss takes place. Recently, 
communities in Earth system modeling have 
started to develop `initial-condition large
ensembles' in state-of-the-art models.  I 
will present a statistical analysis about 
the change of a correlation coefficient 
relating the El Nino--Southern Oscillation
and the Indian monsoon in two of these 
`large ensembles', and illustrate that the
proper  analysis may lead to conclusions 
qualitatively different from those relying
on the time evolution of a single realization,
questioning  conclusions drawn about 
observations in the literature.



1117, Budapest, Pázmány P. sétány 1/A, Északi tömb 2.54
        honlap: http://glu.elte.hu/~statfiz

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