Application of Copula-based Cosimulation for Temporal or Spatial Data in
Earth Science
Abstract
Accurate modeling of dependencies between variables of interest is
imperative for understanding biophysical processes and mechanisms
relevant to Earth Science research. This study presents a methodology to
model the temporal or spatial distributions of variables using
copula-based cosimulation (CopCoSim). This technique models and
simulates the joint distribution of multiple variables by capturing
their dependencies and correlations. We compared CopCoSim with the
traditional Sequential Gaussian CoSimulation (SGCoSim) technique through
two applications relevant to Earth Science representing one (i.e., time)
and two dimensions (i.e., space). We present an application for soil CO2
efflux, which is a major flux in the global carbon budget, using two
case studies: (1) temporal distribution of soil CO2 efflux and
temperature, and (2) spatial distribution of soil CO2 efflux and
temperature across the conterminous United States (CONUS). The
methodology involves three steps: data input, application of stochastic
simulation methods, and comparison of simulation outputs. The results
indicate that CopCoSim provides a better model with higher precision and
accuracy for representing variables of interest. CopCoSim better
reproduces the univariate probability distribution, temporal or spatial
autocorrelation, and dependency relationship between the predictor and
response variables. We propose that CopCoSim is useful for research in
Earth Science, where variables of interest (e.g., soil CO2 efflux and
temperature) are often interdependent and exhibit complex temporal or
spatial patterns.