Abstract
It is important to consider where, when, and how the evolution of sea surface temperature anomalies (SSTA) plays significant roles in regional or global climate changes. In the comparison of where and when, there is a great challenge in clearly describing how SSTA evolves in space and time. In light of the evolution from generation, through development, and to the dissipation of SSTA, this paper proposes a novel approach to identifying an evolution of SSTA in space and time from a time-series of a raster dataset. This method, called PoAIES, includes three key steps. Firstly, a cluster-based method is enhanced to explore spatiotemporal clusters of SSTA, and each cluster of SSTA at a time snapshot is taken as a snapshot object of SSTA. Secondly, the spatiotemporal topologies of snapshot objects of SSTA at successive time snapshots are used to link snapshot objects of SSTA into an evolution object of SSTA, which is called a process object. Here, a linking threshold is automatically determined according to the overlapped areas of the snapshot objects, and only those snapshot objects that meet the specified linking threshold are linked together into a process object. Thirdly, we use a graph-based model to represent a process object of SSTA. A node represents a snapshot object of SSTA, and an edge represents an evolution between two snapshot objects. Using a number of child nodes from an edge’s parent node and a number of parent nodes from the edge’s child node, a type of edge (an evolution relationship) is identified, which shows its development, splitting, merging, or splitting/merging. Finally, an experiment on a simulated dataset is used to demonstrate the effectiveness and the advantages of PoAIES, and a real dataset of satellite-SSTA is used to verify the rationality of PoAIES with the help of ENSO’s relevant knowledge, which may provide new references for global change research.
Highlights
Sea surface temperature (SST) is an essential marine variable [1] and plays an important role in climate change monitoring, weather forecasting, and marine fishery monitoring [2,3]
The Multivariate El Niño-Southern Oscillation (ENSO) Index (MEI) is often used to identify ENSO events, which is divided into eastern Pacific ENSO (EP ENSO) and central Pacific ENSO (CP ENSO)
While these definitions and identifications play a foundational role in mining evolutions of Sea surface temperature anomaly (SSTA), the method based on spatiotemporal topologies of snapshot objects is based on the precondition that the geographical entities at instant time snapshots are independent
Summary
Lianwei Li 1 , Yangfeng Xu 1,2 , Cunjin Xue 2,3, * , Yuxuan Fu 1,2 and Yuanyu Zhang 1,2. Aerospace Information Research Institute, Chinese Academy of Sciences, Beijing 100094, China
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