Visiting scientist position in a frame of the Project 'Descartes - nutation'

Title of the project:
Modeling atmospheric and oceanic contributions to nutation

Host Institution:
Space Research Centre, Polish Academy of Science
Bartycka 18A, 00-716 Warszawa, Poland

Scientist needed:
Preferred candidates are Post-docs, but we can also consider a visit of 
the PhD students.

Period:
Initially 6 months, possible extension to 1 year

Finances (for Post-doc):
She/he will receive a monthly salary of 1000 EURO and in addition we 
will cover costs of the standard accommodation in Warsaw. (Note that 
1000.- EUR a month in Warsaw is by far enough to cover the daily 
expenses, which is not necessarily the case for other European cities.)
Certain amount of money is also reserved to support: her/his travel to
Poland and back, attendance to one international conference abroad (such
as EGU GA or Journees) and one national conference in Poland.

Facilities offered:
The SRC building is located about 4 kilometers from the city center, in
a green environment near the river and far from the traffic areas. It
has regular bus connection to the downtown. It takes between 15 and 20 
minutes to go to the central railway station. The Institute has its own
cantine serving the lunch (also the breakfast upon request) from Monday
to Friday. We offer the visiting scientist the desk in a 2- or maximum
3-person room, PC for personal use with permanent connection to the
Internet, to our local work station as well as to the black-white laser
printer and color ink-jet printer. She/he has an access to the library
during the working hours. She/he will cooperate with the supervisor and
other members of the team, including well-recognized specialists in the
field of Earth rotation, such as Prof. Kolaczek, Drs. Kosek and Nastula.

Scientific Supervision:
Prof. Dr. Aleksander Brzezinski

The objectives and scope of the research:
The subject of the research concerns the contributions to nutation
coming from the coupled system of the external geophysical fluids, the
atmosphere and the ocean. There are two effects which should be
considered:
- The Free Core Nutation (FCN) and possibly other resonant signals 
  within the nutation frequency band;
- The atmospheric/oceanic contributions to the amplitudes of the
  nutation waves, mostly the prograde annual wave corresponding to the
  S1 thermal diurnal tide.
These two contributions contain irregular variability at the level of
0.1 mas (milliarcsecond) which should be properly understood if we like
to increase the accuracy of the conventional precession-nutation model.
The proposed research covers the following problems:
1) Modeling the FCN signal in the celestial pole offsets observed by the
   VLBI technique. An important question which should be addressed is: 
   Are the available time series of nutation all equally suited for this
   purpose or some of them are better than the others?
2) Analysis of the available atmospheric angular momentum (AAM) series
   in the retrograde diurnal frequency band corresponding to nutation.
   Question: is it possible to improve the estimation of the AAM using
   the same sets of the meteorological observations in order to increase
   its reliability within the nutation band?
3) Analysis of the available nontidal oceanic angular momentum (OAM)
   series in the nutation band and comparison with the corresponding AAM
   data and with the VLBI nutation observations. Questions: Does the OAM
   improve the excitation balance in the nutation band, including the
   FCN signal? How the dynamical model of the ocean response to the
   atmospheric forcing is related to the other two simple models applied
   so far, the non-IB and IB models? Can the estimation of the subdaily
   OAM series be improved in order to increase the reliability within
   the nutation band?

It is expected that the results of the proposed research will be
presented at an international conference, such as the EGU General
Assembly or the Journees Systemes de Reference Spatio-Temporels, and
submitted for publication in a reviewed journal.

For more details please contact:
Aleksander Brzezinski
e-mail alek@cbk.waw.pl
ph. +48/22/840-37-66 ext. 287
fax. +48/22/840-31-31