The objective of climate-analogue mapping is to show graphically where similar climates are likely to be found, usually by comparing the climate at a point with climates over a spatial array, grid, or field of points.  In the simplest of applications, the climate of a particular, or "target,"  point is compared with the climate of the grid of points by plotting dissimilarity values; typically, the map patterns of the dissimilarities will show a pattern of distance decay, where the climates of the field of points grow increasingly less similar as distance from the particular point increases. Climate analogues can also be mapped for climates at different times, comparing, say, the present climate at a point with the projected future climate over a field of points.  In this way, the analogues provide a way of gauging the size of the projected future change.  Small climate changes will show patterns of dissimilarities similar to a comparison among modern climates, whereas large projected changes in climate may show a pattern with the small dissimilarities (most analogous climates) lying in regions distant from the target point.
The application here shows graphically where the present-day climate of a location will be in the future (i.e., where the present climate is going to), and where the future climate of the location is at present (where the future climate is coming from). There are multiple ways of calculating the analogues that require the choice of a particular climate model and emissions secenario, time (e.g. mid- vs. end-century), the particular climate variables the analogues are based on, whether the variables should be transformed or not, and the specific dissimilarity measured used.  These choices basically involve specifying the data (i.e. the scenario, model, time and variables used (the "analogue basis')), and the method (transformation and dissimilarity measure) used to calculate the analogues. The data and method choices are made using the drop-down list boxes on the Analogue Selector page, and the analogue maps can be viewed by clicking on a location.  (Note: Due to space limitations, downloadable netCDF files of analogues are not available here at this time.)  Click on the following links to begin or for more information:
[Analog selector page (analogue mapping test page)]  [directions]  [notes]