![]() Very large wind farm just east of San Francisco BayĪdditional ground clutter beyond what is always visible for a given radar site sometimes appears as a result of “anomalous propagation” or AP. Wind farm very close to the Dodge City radar where the rows of turbines can be seen in the reflectivity data Even though the turbines themselves don’t move, the radar will frequently display non-zero velocity in wind farms because of the spinning blades. Some radars, such as KVNX, KDDC, and KDAX, have nearby wind farms that always show up, but most only show up on radar when the beam stays closer to the ground than normal, usually early in the morning. There is also a map of wind turbines maintained by the USGS, though it may not include some of the newest wind farms. The satellite layer on Google maps can confirm the presence of a wind farm. Sometimes, it is possible to see the individual rows of turbines, as in the example from Dodge City. It has unrealistically large reflectivity gradients along the edges (goes from nothing to 60+ dBZ in one or two pixels) and noisy values in the interior (a 40 next to a 50, next to a 70, next to a 30, etc.). Wind farms are distinguished on radar data as small regions of very high reflectivity that don’t move. One of the most common ground clutter artifacts that attracts significant attention is wind farms, mostly because of the tendency for very high reflectivity that looks like a thunderstorm. Part 3 - Ground Clutter and Other Stuff Wind Farms Satellite data can also be helpful for determining if there is a fire or significant cloud cover in the area of interest. Smoke and chaff can be most readily distinguished from precipitation by the low correlation coefficient. Some ground clutter is almost constant, but in general, it tends to be worst during the night or early in the morning. When watching a loop, it tends to suddenly appear and disappear in the same area, rather than moving. The correlation coefficient is generally very low, and differential reflectivity tends to be near zero but can be variable. Sometimes there will be pixels of missing/no data/zero within a group of pixels with high values. Ground clutter is generally characterized by isolated, noisy large values of reflectivity and velocity that move very little if at all. #Mid detail dexture vs optimized ground clutter seriesThe third part of the series will focus on various forms of ground clutter and miscellaneous things like smoke and chaff. ![]()
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