High-resolution atmospheric angular momentum functions related to Earth rotation parameters during CONT08 Michael Schindelegger JohannesB¨ohm David Salstein Harald Schuh M. Schindelegger, J. Boehm, H. Schuh: Institute of Geodesy and Geophysics, Vienna University of Technology Gußhausstraße 27-29, 1040 Vienna, Austria michael.schindelegger@tuwien.ac.at D. Salstein: Atmospheric and Environmental Research, Lexington, U.S.A Abstract Due to the temporal resolution of available numerical weather analyses, the effect of the atmosphere on Earth rotation at daily and sub-daily periods is usually investigated by using six-hourly atmospheric angular momentum (AAM) functions. During the period of CONT08, however, atmospheric analysis data were provided by the European Centre for Medium-Range Weather Forecasts (ECMWF) also on an hourly basis. In this paper, we therefore determine two sets of AAM functions from ECMWF data - one for CONT08 with hourly resolution and one for the year 2008 with six-hourly resolution. The comparisons of the AAM functions to high-resolution Earth Rotation Parameters (ERP) from VLBI and GPS observations are carried out in the frequency domain. Special attention is paid to the preparation of the high-resolution data sets for the geodetic purposes, as there are jump discontinuities at 12 hour intervals. Hence, the hourly AAM functions need to be concatenated. The revised functions yield much smaller amplitudes than their six- 1