Open AccessA sampling method for improving the representation of spatially varying precipitation and soil moisture using the Simple Biosphere Model
Author(s) -
Medina Isaac D.,
Denning A. Scott,
Baker Ian T.,
Ramirez Jorge A.,
Randall David A.
Publication year - 2014
Publication title -
journal of advances in modeling earth systems
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.03
H-Index - 58
ISSN - 1942-2466
DOI - 10.1002/2013ms000251
Subject(s) - sampling (signal processing) , precipitation , biosphere , grid , environmental science , water content , representation (politics) , moisture , biosphere model , soil science , meteorology , computer science , mathematics , geology , ecology , physics , geometry , geotechnical engineering , filter (signal processing) , politics , political science , law , computer vision , biology
Representing spatially varying precipitation for current grid length scales used in General Circulation Models (GCMs) is a continuing challenge. Furthermore, to fully capture the hydrologic effects of nonuniform precipitation, a representation of soil moisture heterogeneity and distribution of spatially varying precipitation must exist within the same framework. For this study, the explicit and sampling methods of Sellers et al . (2007) are tested off‐line using the Simple Biosphere Model (SiB3) in an arid, semiarid, and wet site, and are numerically compared to the bulk method, which is currently used in GCMs. To carry out the numerical experiments, an arbitrary grid area was defined by (1) a single instance of SiB3 (bulk method), (2) 100 instances of SiB3 (explicit method), and (3) less than 100 instances of SiB3 (sampling method). Precipitation was randomly distributed over fractions of the grid area for the explicit and sampling methods, while the standard SiB3 exponential distribution relating precipitation intensity to the grid area wet fraction was used in the bulk method. Comparing the sampling and bulk method to the explicit method indicates that 10 instances of SiB3 in the sampling method better captures the spatial variability in soil moisture and grid area flux calculations produced by the explicit method, and deals realistically with spatially varying precipitation at little additional computational cost to the bulk method.