A comparison of search strategies to design the cokriging neighborhood for predicting coregionalized variables

Nasser Madani, Xavier Emery

Research output: Contribution to journalArticle

12 Citations (Scopus)

Abstract

Cokriging allows predicting coregionalized variables from sampling information, by considering their spatial joint dependence structure. When secondary covariates are available exhaustively, solving the cokriging equations may become prohibitive, which motivates the use of a moving search neighborhood to select a subset of data, based on their closeness to the target location and the screen effect approximation. This paper investigates the efficiency of different strategies for designing a sub-optimal neighborhood wherein the simplification of the cokriging equations is challenging. To do so, five alternatives (single search, multiple search, strictly collocated search, multi-collocated search and isotopic search) are tested and compared with the reference unique neighborhood, through synthetic examples with different data configurations and spatial joint correlation models. The results indicate that the multi-collocated and multiple searches bear the highest resemblance to the reference case under the analyzed spatial structure models, while the single and the isotopic searches, which do not differentiate the primary and secondary sampling designs, yield the poorest results in terms of cokriging error variance.

Original languageEnglish
Pages (from-to)1-17
Number of pages17
JournalStochastic Environmental Research and Risk Assessment
DOIs
Publication statusAccepted/In press - Jul 6 2018

Keywords

  • Cokriging neighborhood
  • Heterotopic sampling
  • Intrinsic correlation
  • Markov-type models
  • Multi-collocated cokriging
  • Screening effect
  • Strictly collocated cokriging

ASJC Scopus subject areas

  • Environmental Engineering
  • Environmental Chemistry
  • Water Science and Technology
  • Safety, Risk, Reliability and Quality
  • Environmental Science(all)

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