A diagram for evaluating multiple aspects of model performance in simulating vector fields
Vector quantities, e.g., vector winds, play an extremely important role in climate systems. The energy and water exchanges between different regions are strongly dominated by wind, which in turn shapes the regional climate. Thus, how well climate models can simulate vector fields directly affects mo...
Main Authors: | , , , |
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Format: | Article |
Language: | English |
Published: |
Copernicus Publications
2016-12-01
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Series: | Geoscientific Model Development |
Online Access: | http://www.geosci-model-dev.net/9/4365/2016/gmd-9-4365-2016.pdf |
Summary: | Vector quantities, e.g., vector winds, play an extremely
important role in climate systems. The energy and water exchanges between
different regions are strongly dominated by wind, which in turn shapes the
regional climate. Thus, how well climate models can simulate vector fields
directly affects model performance in reproducing the nature of a regional
climate. This paper devises a new diagram, termed the vector field
evaluation (VFE) diagram, which is a generalized Taylor diagram and able to
provide a concise evaluation of model performance in simulating vector
fields. The diagram can measure how well two vector fields match each other
in terms of three statistical variables, i.e., the vector similarity
coefficient, root mean square length (RMSL), and root mean square vector
difference (RMSVD). Similar to the Taylor diagram, the VFE diagram is
especially useful for evaluating climate models. The pattern similarity of
two vector fields is measured by a vector similarity coefficient (VSC) that
is defined by the arithmetic mean of the inner product of normalized vector
pairs. Examples are provided, showing that VSC can identify how close one
vector field resembles another. Note that VSC can only describe the pattern
similarity, and it does not reflect the systematic difference in the mean
vector length between two vector fields. To measure the vector length, RMSL
is included in the diagram. The third variable, RMSVD, is used to identify
the magnitude of the overall difference between two vector fields. Examples
show that the VFE diagram can clearly illustrate the extent to which the
overall RMSVD is attributed to the systematic difference in RMSL and how
much is due to the poor pattern similarity. |
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ISSN: | 1991-959X 1991-9603 |