Test results for trend extraction algorithms (Table S1)

Studies of climate change typically consider measurements or predictions of temperature over extended periods of time. Climate, however, is much more than temperature. Over the oceans, changes in wind speed and the surface gravity waves generated by such winds play an important role. We used a 23-year database of calibrated and validated satellite altimeter measurements to investigate global changes in oceanic wind speed and wave height over this period. This table summarises the values of trend determined by the various tests, together with 95% confidence limits for the trend. Several different trend extraction algorithms were used: linear regression; linear plus seasonal; Mann-Kendall test; Seasonal Kendall test and Singular Spectrum Analysis. The target value for the trend in this test is 0.5 x 10^2 units/yr. Singular Spectrum Analysis (SSA) was used to 'filter' the time series. The trend of the filtered time series was then determined using the MK test. The confidence limits are for this filtered time series