Reconstruction of global sea level variations from tide gauges and altimetry

Sea level variations prior to the launch of satellite altimeters are estimated by analysing historic \ntide gauge records. Recently, a number of groups have reconstructed sea level by applying EOF \ntechniques to gappy data. We complement this study with alternative methods. In a first step gaps \nin 178 records of sea level change are filled using the pattern recognition capabilities of artificial \nneural networks. Afterwards satellite altimetry is used to extrapolate local sea level change to \nglobal fields. Patterns of sea level change are compared to prior studies. Global mean sea level \nchange since 1900 is found to be on average 1.65 mm per year.