************************************************************************ IERS Message No. 60 August 12, 2004 ************************************************************************ 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 ************************************************************************ IERS Messages are edited and distributed by the IERS Central Bureau. To subscribe or unsubscribe, please write to . Archives: http://www.iers.org/iers/publications/messages/ ************************************************************************