HR: 12:05h
AN: G42A-08    [Abstracts]
TI: Regional contributions of atmosphere and oceans to transient changes of the Earth's rotation
AU: * Dobslaw, H
EM: dobslaw@gfz-potsdam.de
AF: GeoForschungsZentrum Potsdam Section 1.5 Earth System Modeling, Telegrafenberg, Potsdam, 14473, Germany
AU: Thomas, M
EM: mthomas@gfz-potsdam.de
AF: GeoForschungsZentrum Potsdam Section 1.5 Earth System Modeling, Telegrafenberg, Potsdam, 14473, Germany
AU: Groetzsch, A
EM: groetz@gfz-potsdam.de
AF: GeoForschungsZentrum Potsdam Section 1.5 Earth System Modeling, Telegrafenberg, Potsdam, 14473, Germany
AB: The time-variable Earth's rotation is precisely monitored by space-geodetic techniques. Beside periodic phenomena, distinct transient signals are apparent, which are predominantly related to near-surface processes of the Earth system. However, since observations of Earth rotation represent an integral signal of the Earth's response to internal and external forces, they are principally not applicable to directly identify the contributions of individual regions or processes. Instead, sophisticated numerical models are required in order to relate observed rotational variations to their causative dynamical processes. Here, a numerical modelling approach of Earth system dynamics is presented allowing for consistent fluxes of mass, momentum and heat between the sub-systems atmosphere, oceans and continental hydrology. Operational atmospheric analyses from ECMWF are used to force a hydrological discharge model as well as a global model for the ocean's baroclinic circulation and ephemeral tides. The unconstrained hydrology and ocean models are coupled via continental discharge in order to close the hydrological cycle. Focussing on the period 2001 - 2006, observed rotational variations are contrasted to simulated individual excitations of atmosphere, oceans, and continental hydrology in order to attribute characteristical signals of Earth rotation to underlying physical processes and to identify regional contributions to the total excitation of Earth rotation. By means of a comparing analysis of observations and simulations it will be discussed to what extent Earth rotation observations can be used to monitor climate relevant dynamics in the atmosphere-hydrosphere system.
DE: 1222 Ocean monitoring with geodetic techniques (1225, 1641, 3010, 4532, 4556, 4560, 6959)
DE: 1225 Global change from geodesy (1222, 1622, 1630, 1641, 1645, 4556)
DE: 1239 Earth rotation variations
SC: Geodesy [G]
MN: 2007 Fall Meeting