Sst Long Time Series Analysis And The Relationship With Human Activities

The ocean accounting for about70percent of the Earth’s surface is the cradle ofthe life. The ocean is the regulator of the climate, which is an important part of theEarth system. In order to study the changes of the ocean in global warming, weanalyze global sea surface temperature （SST） time series using the sea surfacetemperature data set, ERSST V2, from January1st,1854to December31st,2008. Withthe analysis, we get the characteristics of global SST variability in time. At the sametime, using the SST variance we define the areas where the SST has largerfluctuations, called high value area in paper. We summarize the distributioncharacteristics of the high value areas and their SST variability modality. Comparedwith the common method, the spectral analysis, SST variance and the correlation canalso define the critical areas of the SST, whose calculation is more simple and faster.But the SST variance can’t indicate the frequency features. At present, a lot ofevidences prove that the excess CO₂emission is the chief culprit in global warming.In the process of climate change, do human activities have an effect on the SSTvariability? For this question, we study the effect on the SST variability, human beingeconomic activities playing through atmosphere, with the economics as the startingpoint and the CO₂concentration as the connection point. After the above researchwork, we have got some significant conclusions:First, the global SST showed a warming trend during1854²008. This processcan be divided into three stages:1850s to1910, SST steps down stage;1910to the1960s, SST gradual recovery stage;1970s to the present, SST keeps on increasing stage. The global SST have a significantly heating up in summer, which is July,August, September in the Northern Hemisphere and March, April, May in theSouthern Hemisphere. In the view of the space, the areas where global SST has lagervariability is equatorial and mid-latitude waters, and also Atlantic and eastern Pacific.Second, using the EOF analysis of global SST anomaly, we find the equatorialPacific, the Indian Ocean and the southern tip of the Horn of the Africa are the areashaving increasing SST variability. And the SST drops down mainly in the NorthernHemisphere mid-latitude waters. Using the distribution of global SST variance, wedefined four areas having sensitive SST variability, referred the high value area. Thefour areas are the equatorial central and eastern Pacific, the Northern Hemispheremid-latitude Pacific, the Northern Hemisphere mid-latitude Atlantic and the waters tothe southwestern tip of Africa. Overall, the SST variability in the NorthernHemisphere is larger than in the Southern Hemisphere. Different high value areashave different variability modality. Through the analysis of the SST correlationbetween the high value areas and global data grid points, we find the high-frequencymodality exist mainly in the lower latitudes waters, and the low-frequency modalityexist mainly in the middle latitude waters.Third, GDP growth is an important indicator to describe the human social andeconomic activities, which can reflect the economic crises, wars and political eventsand so on. The human economic activities reflect the speed of CO₂emission growth.The CO₂emission growth will become bigger with the bigger GDP growth. Themainly reason of atmospheric CO₂concentration growth is the excessive CO₂emission from human activities. Moreover, the nature plays an important role in thechange of atmospheric CO₂concentration.Fourth, through the wavelet analysis, we found the growth of GDP, CO₂emissions and atmospheric CO₂have the cycles of2⁸years, which is similar withthe cycles of ENSO. In the interaction of ocean and atmospheric CO₂, the oceanmainly plays the driving role, and the atmospheric CO₂plays the response role. Due to this, human activities have little effect on the ocean change through atmosphericCO₂. ENSO is an important phenomenon effecting the atmospheric CO₂concentration,whose influence scope is so broad to the polar region. The atmospheric lags theENSO change for8to12months.