Changing trends and relationship between global ocean chlorophyll and sea surface temperature

With the MODIS Aqua satellite-derived ocean chlorophyll concentration and sea surface temperature(SST) time series data, recent changing trends were evaluated by linear regression analysis. Furthermore, the time frequency space and regions in time frequency space where the chlorophyll and SST time series show high common power and phase angle were explored and found with Continuous wavelet transform (CWT) and Cross wavelet transform(XWT) methods. Results showed that during 2003-2009, the global ocean chlorophyll concentration is increasing while the SST is decreasing. There is a stable one year frequency in the global ocean chlorophyll for the whole time period but a half year frequency only in 2007-2009. To the SST, there are a stable one year and half year frequency during 2003-2009. There is a stable one and an unstable 0.5 year resonance frequency between global ocean chlorophyll and SST. The phase angle between global ocean chlorophyll and SST increased from 130° to 180 °for one year resonance frequency and phase relationship changed from in-phase to anti-phase for 0.5 year frequency after 2006.