The elimination of spurious trends in marine wind data using pressure observations

摘要

The use of pressure reports from merchant ships provides a reasonable way to correct the trends in marine wind data. However, the appropriate method to derive pressure gradients from the ship data is controversial. Three principal proceedings are analysed: The method of using three simultaneous pressure observations, the method of deriving monthly mean pressure gradients, and the method presented by Lindau (1995). For the first two, it is shown that they are unable to provide reliable reference values for wind speed; if observation triples are used, random errors in the raw data cause systematic errors in the derived pressure gradients. The problem concerning monthly mean pressure gradients is that they are only proportional to the vector,wind, but not to the scalar wind. Therefore, these methods are inapplicable for calibration purposes. The method of Lindau (1995) is recommended for a proper elimination Of Spurious trends in marine wind observations. Copyright (C) 2006 Royal Meteorological Society.