Breeding vectors and predictability in the Oxford Mars GCM

Details Breeding vectors and predictability in the Oxford Mars GCM Breeding vectors and predictability in the Oxford Mars GCM

Apr 2003

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2003eaeja.....2308n&link_type=abstract

EGS - AGU - EUG Joint Assembly, Abstracts from the meeting held in Nice, France, 6 - 11 April 2003, abstract #2308

Statistics

Applications

Scientific paper

A breeding vectors approach is used to study the intrinsic predictability of the Martian atmosphere using the Oxford Mars General Circulation Model. Breeding vectors are commonly used to find dominant modes of instability in the Earth's atmosphere, usually to provide optimal initial perturbations for ensemble forecasting experiments. They are produced by adding random perturbations to an initial model state, then running both the perturbed and control models for a few hours (or whatever the length of the `breeding cycle'), after which time the size of the perturbation (the difference between the models after this amount of time) is renormalized to the initial size, where size is defined using some global `norm'. Renormalization is necessary to prevent nonlinear saturation of the instabilities of interest. The size of the initial perturbations may in fact be chosen to filter out naturally any instabilities which have fast growth factors, but which saturate at too small amplitudes for them to be important in forecasting applications. The fastest growing modes are spatially larger than those in the Earth's atmosphere. For large initial temperature perturbations (with an average size of about 5K), they peak in northern high latitudes at equinox and in the winter hemisphere at solstice, for a range of different dust loadings. The modes extend through almost the entire vertical domain at equinox, but maximum values are confined to above about 40km at solstice. For most seasons and dust loadings, however, there is little or no net growth of these perturbations during each breeding cycle (except during dusty southern summer conditions), and growth rates are quite variable. When smaller initial perturbations are used growth rates are generally increased, particularly for dusty solsticial conditions. The implications of these results for the predictability of the Martian atmosphere, and for the usage of ensemble forecasting methods on Mars, will be discussed.

Affiliated with

Also associated with

No associations

Rating

Breeding vectors and predictability in the Oxford Mars GCM does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Breeding vectors and predictability in the Oxford Mars GCM, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Breeding vectors and predictability in the Oxford Mars GCM will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-841665