Visualization of Uncertainty in Meteorological Forecast Models

Elizabeth Dirks Fauerbach, Robert M. Edsall, David Barnes, Alan M. MacEachren
Web site: http://www.geovista.psu.edu/sites/icavis/icavis/febm.html

Purpose of the System

1. The system is a prototypical visualization application designed to explain the spatio-temporal reliability of 3 weather forecast models by enlisting the use of animation of environmental data to examine change in data reliability over time.
2. The prototype enables an analyst to compare results/predictions of these individual meteorological models to one another, to observe the relationship between an average of the models and the amount of divergence from that average, and to contrast the actual weather that they attempt to forecast.
3. Put simply, to predict the weather and access the accuracy of existing forecast models.

Uncertainty Information

The uncertainty information is the predictions of the individual meteorological forecast models, or georeferenced forecasts-or rather, determining the reliability and accuracy of these models.

Input Data

1. Georeferenced data (in the form of static maps) that includes a temporal and spatial component with the primary goal of understanding changes in spatial patterns over time.
2. 24 forecast data sets (8 data sets from each model) from one release time, 7am on 2/2/95.
3. Isobars: line of equal pressure-parameter used for measuring
4. Surface pressure.

Visualization Clues/Queues

1. 3 models, the eta, NGM, and spectral-all used by the National Meteorological Center to provide a short-term (2-day) forecast.
2. Each of these models is released by the NMC as a series of static maps, each representing one "time slice" of the 48-hour period that forecasts conditions during that time. Each of these forecasts is stored as a grid of points, equally placed on a base map of North America, at a spatial resolution of approx. one point per 50 km.

User Interface

1. The data is formatted in an array of 40 columns and 30 rows, which corresponds to the area of the continental United States and some of southern Canada. The application is viewed from a browser with Shockwave enabled. The completed interactive animation application allows the user to view several variables simultaneously or separately, which can reveal otherwise hidden characteristics of the data. In this particular case, the animations of the models' storm tracks, displayed simultaneously, reveal that a key component of uncertainty surrounding the storm is temporal discrepancy of the models.
2. A feature of the system that provides further insight into the data is the interactive control over the animation provided by Director. The ability to change the pace of the movie or to step through the animation one frame at a time shows details about the data that would be difficult if not impossible to detect otherwise.

Future Work

At this point, the prototype is hardwired to a particular data set. In order for this application to be of real use, it must be implemented in a datadriven environment in which analysts can easily apply the tool to any data set of interest.