Some problems in the reconstruction of mean sea level and its changes with time

摘要

The ocean level is constantly changing and there are many different forcing functions. Today, we realize that a rise in one area may, in fact, correspond to a fall in another area. A number of problems or pit-falls in sea level analyses are highlighted; viz. the significance of shore morphology, the multiple possible causes of coastal erosion, the necessity to consider cyclic changes, not least the 18.6 tidal cycle and its relation to our tide-gauge records, the effects of redistribution of ocean water masses, the problems with many sea level curves based solely on isolation levels, and the problems of transferring time/depth graphs into rates of sedimentation and sea level rise without having investigated and calibrated for ongoing consolidation in the top-part of the sediment sequence; i.e. the zone of active compaction. Therefore, the necessity of multi-parameter analyses is strongly proposed.