1. ARCGICE WP 2.1 Leader: DSPC Make new geoid of afrctic region based on GRACE C.C.Tscherning, University of Copenhagen, 2005-03-01 1

2. Observations: Parameter is equal to N 0 mean sea surface height A i = 1 if bias only for all values of i which are associated with geoid heights. Parameter and error-estimation C.C.Tscherning, University of Copenhagen, 2005-01-13 2

3. Then an estimate of T and of the parameters X are obtained as where W is the a-priori weight matrix for the parameters (Generally the zero matrix). Parameter estimate C.C.Tscherning, University of Copenhagen, 2005-01-13 3

4. Data may be gridded, so that spherical FFT can be used. (GEOCOL). Data gridding C.C.Tscherning, University of Copenhagen, 2005-01-13 4