Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: North Atlantic thermohaline circulation predictability in a coupled
  ocean-atmosphere model   Predictability of the North Atlantic thermohaline circulation (THC)
variability as simulated in the GFDL coupled ocean-atmosphere general
circulation model is established for a set of ensemble experiments. The
ensembles consist of identical oceanic initial conditions underneath a model
atmosphere chosen randomly from the model climatology. This experimental design
is based on the separation in time scales present in the model which motivates
the assumption that the predictability deduced from these ensembles provides an
upper limit to the model's THC predictability. The climatology is taken from a
multi-century model integration whose THC variability has power concentrated at
the 40-60 year time scale. A linear stochastic perspective is shown to be
generally consistent with the ensemble statistics. The linear theory suggests a
natural measure of ensemble predictability as the time at which the ensemble
variance becomes a subjectively defined fraction (0.5 used here) of the
climatological variance. It is furthermore of interest to distinguish
predictability of the rapidly de-correlating portion of the model's THC from
the longer time correlated portion. The rapidly de-correlating portion shows
predictability for $\approx 1.5$ years. The slower portion shows predictability
for $\approx 5-7$ years. The linear stochastic framework provides for the
straightforward construction of an optimal forecast of the model's THC
variability and an understanding of why the optimal forecast is useless beyond
a particular limit.

20
The categories of this paper are: acc-phys
24
The categories of this paper are: dg-ga
18
The categories of this paper are: econ
34
The categories of this paper are: chem-ph
21
The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex
29
The categories of this paper are: funct-an
36
The categories of this paper are: cmp-lg
5
The categories of this paper are: gr-qc
9
The categories of this paper are: nlin
16
The categories of this paper are: stat
6
The categories of this paper are: astro-ph
17
The categories of this paper are: q-fin
8
The categories of this paper are: hep-ex
0
The categories of this paper are: hep-ph
35
The categories of this paper are: mtrl-th