MODE-TD: An Expansion of an Object-based Spatial Method

The Model Evaluation Tools (MET) has been supported to the community via the Developmental Testbed Center for many years. One of the core tools within MET is the Method for Object Based Evaluation (MODE). MODE tool requires two gridded fields. MODE uses a convolution operator to smooth the field prior to thresholding to identify the salient objects. Once objects are identified in each field, they are matched between the fields and, if desired, additional merging may be performed. The attributes of the matched pairs provide meaningful diagnostic information about displacement, size and intensity errors. MODE has been used on a diverse group of fields, including probability fields for storm-scale ensembles to drought indices for long-term climate models. MODE was recently extended to define objects in the 2-dimensional space and then follow them through time, creating 3-dimensional objects that can be matched. The resulting tool is called MODE-TD and provides information about timing, duration, and velocity. This presentation will describe how MODE-TD defines objects, what additional attributes are derived and provide examples demonstrating it's potential use.