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North American Regional Reanalysis (NARR)

A sub-region plot of NARR underground soil temperature (a layer from 10cm to 40cm below ground) at 18UTC on September 18, 2003. This image was produced by downloading one file of NARR data through NOMADS and visualizing with the Grid Analysis and Display System (GrADS).

The North American Regional Reanalysis (NARR) is a regional reanalysis of North America containing temperatures, winds, moisture, soil data, and dozens of other parameters. Produced by the National Centers for Environmental Prediction (NCEP), the NARR model takes in, or assimilates, a great amount of observational data to produce a long-term picture of weather over North America. The data that are assimilated in order to initialize the model to real-world conditions are temperatures, winds, and moisture from radiosondes as well as pressure data from surface observations. Also included in this dataset are dropsondes, pibals, aircraft temperatures and winds, satellite radiance (a measure of heat) from polar (orbiting the Earth) satellites, and cloud drift winds from geostationary (fixed at one location viewing the Earth) satellites. Use of a regional weather model over the North American continent has produced a dataset with a period of record spanning from 1979 to present. The horizontal distance between grid points in the NARR dataset is an impressive 20 miles, or 32 kilometers, apart.

A plot of NARR data zoomed-in on Hurricane Isabel making landfall on September 18, 2003 at 18UTC. This plot shows the total amount of water (in a vertical column of air) being zonally transported in the atmosphere. The northern bull's-eye shows a strong westward motion of water, while the southern bull's-eye shows a strong eastward motion of water--indicating the strong cyclonic motion of the hurricane. Data contours were generated with the Grid Analysis and Display System (GrADS) and visualized with Google Earth.