Spatiotemporal Association Patterns Mining And Study Of Marine Net Primary Production

Marine net primary productivity(NPP)is an important parameter in marine ecosystems,which shows different regional differences and evolution characteristics under the dual effects of natural environment and human activitiesand,and lack of systematic research.Satellite remote sensing data have the characteristics of large area coverage and long time series observation,which provide a new solution for the study of NPP.The data mining technology has been widely used in the analysis and research of ocean spatiotemporal association patterns,and this method doesn't need priori knowledge.This paper study the relationships between NPP and marine environmental parameters,human activities from the perspective of spatiotemporal association mining.In details:1.An association rules mining algorithm for NPP is design based on the concept and definition of association rule mining.The core ideas of the algorithm are'link-prune' and taking NPP as the core item.The specific implementation process is as follows:generating temporary transaction tables,generating frequent 1-itemset,generating frequent 2-itemset that only contain NPP,performming recursive operations,generating strong association rules.This algorithm's main advantages are as follow:the results with geographic coordinate information will provide the basis help for geographic analysis,this algorithm takes the net primary productivity as the core item,and it will greatly reducs the generation of frequent itemsets and improvs algorithmic efficiency.2.This paper minings and analysises the spatiotemporal association patterns among NPP and sea surface temperature(SST),sea level anomalies(SLA),sea surface precipitation(SSP),mixed layer depth(MLD),sea surface wind speed(WS),El Nino-Southern Oscillation(ENSO)events,using the remote sensing products covering a 20-year period from Jan 1998 to Dec 2017.The main results are as followings:1)In the western equatorial Pacific Ocean(PO),an abnormal decrease of SLA,an abnormal decrease of SSP,an abnormal increase of MLD,or an abnormal increase of WS increase the supply of nutrients to phytoplankton in the euphotic zone,which results in an abnormal increase of NPP.2)In the middle equatorial PO,an abnormal increase of SLA,an abnormal increase of SSP,an abnormal decrease of MLD,or an abnormal decrease of WS reduces the supply of nutrients to phytoplankton in the euphotic zone,which results in an abnormal decrease of NPR 3)In the eastern equatorial PO,an abnormal increase of SLA or an abnormal increase of SSP reduces the supply of nutrients,and an abnormal increase of MLD and WS lower the micronutrient iron in the surface oceans,all of them could lead to an abnormal decrease of NPP.4)In the south PO,the abundance of phytoplankton cell is a negative correlation with the nutrition concentration,thus,an abnormal increase/decrease of SST could improve/reduce the photo synthetic efficiency of phytoplankton,an abnormal increase/decrease of SLA reduces/improves the supply of nutrients to phytoplankton,and those abnormal changes causes an abnormal increase/decrease of NPP.5)El Nino events are more likely to result in the anomalous variations of NPP compared to the La Nina events.3.This paper contrastive analysis the five estuary areas'(Yangtze River estuary area,Pearl River estuary area,Mississippi River estuary area,Nile estuary area,Zambezi River estuary area.)annual,seasonal and monthly spatial and temporal distribution characteristics of marine net primary productivity and their trends of change characteristics.Then,this paper explores the correlation between ocean primary productivity and night light data,land use and cover data,population density data,PM2.5 data,human activity intensity index using the remote sensing products covering the period from 1998 to 2017.The results show that:there is a positive correlation between the change of marine primary productivity and human activity data in estuary area,the highly correlated regions are mainly concentrated in estuaries of rivers and coastal areas of continents,the freshwater flows into and atmospheric aerosol transport are two main ways of influencing marine primary productivity in coastal waters.Figure 27 table 8 reference 74...