A novel set of geometric verification test fields with application to distance measures

Author(s)
Eric Gilleland, Gregor Skok, Barbara G. Brown, Barbara Casati, Manfred Dorninger, Marion P. Mittermaier, Nigel Roberts, Laurence J. Wilson
Abstract

As part of the second phase of the spatial forecast verification intercomparison project (ICP), dubbed the Mesoscale Verification Intercomparison in Complex Terrain (MesoVICT) project, a new set of idealized test fields is prepared. This paper describes these new fields and their rationale and uses them to analyze a number of summary measures associated with distance and geometric-based approaches. The results provide guidance about how they inform about performance under various scenarios. The new case comparisons are grouped into four categories: (i) pathological situations such as when a variable is zero valued at all grid points; (ii) circular events aimed at evaluating how different methods handle contrived situations, such as equal but opposite translations, the presence of multiple events of same/different size, boundary effects, and the influence of the positioning of events in the domain; (iii) elliptical events representing simplified scenarios that mimic commonly encountered weather phenomena in complex terrain; and (iv) cases aimed at analyzing how the verification methods handle small-scale scattered events, very large events with holes (e.g., a small portion of clear sky on a cloudy overcast day), and the presence of noise in one or both fields. Results show that all analyzed measures perform poorly in the pathological setting. They are either not able to provide a result at all or they instigate a special rule to prescribe a value resulting in erratic results. The analysis also showed that methods provide similar information in many situations, but that each has its positive properties along with certain unique limitations.

Organisation(s)
Department of Meteorology and Geophysics
External organisation(s)
National Center for Atmospheric Research (NCAR), University of Ljubljana, Environment and Climate Change Canada, MetOffice
Journal
Monthly Weather Review
Volume
148
Pages
1653-1673
No. of pages
21
ISSN
0027-0644
DOI
https://doi.org/10.1175/MWR-D-19-0256.1
Publication date
04-2020
Peer reviewed
Yes
Austrian Fields of Science 2012
105206 Meteorology
ASJC Scopus subject areas
Atmospheric Science
Portal url
https://ucrisportal.univie.ac.at/en/publications/a-novel-set-of-geometric-verification-test-fields-with-application-to-distance-measures(2c90c72c-455c-443c-94a9-dbe8a5f36453).html