In terms of precipitation, you can expect it to rain a bit less than half of the time. Humidity is generally between 50 and 60% during the day. Temperatures tend to hover around the 50s F (mid 10s C) during the day, while at night they can dip into the low 30s F (single digits C). If you visit Topeka during March, you will probably find that it is crisp. This is worth investing in for this weather. Waterproof jacket that can be used in snow For visiting Topeka, a great option is these boots: In addition to standard footwear, it's important to bring snow boots. It rains sometimes and snows occasionally. Temperatures average in the low 30s F (single digits C) during the day. The correlation coefficient is also noticeably lower when viewing the birds from behind versus from the front, but all the biological scatter is much lower than the precipitation to the north (correlation coefficient near 1).January here is pretty cool. The data look this way because birds look different to the radar when viewed head-on (toward the north or south) or from the side (toward the east or west), and all the birds are oriented the same way. Differential reflectivity is high to the east and west, but lower to the north and south. The dual-pol variables, in this case, show a unique directional signature.
However, most of the remaining return is from birds flying north, so the velocity data indicates motion toward the north, except for the showers and outflow boundaries to the north that are moving southeast, consistent with prevailing mid-level winds. In the below example from Topeka, KS, the prevailing winds are from the west or northwest, consistent with the direction the rain showers are moving. One key thing that can distinguish migrating birds from insects is that the radar velocity may be different from the prevailing wind. In general, the pattern is similar to the “bloom” pattern above, in that reflectivity ramps up shortly after sunset in a large circle or ring surrounding the radar. Radar Aeroecology Understanding Radar and Birds Migratory Birds Did you know that some researchers use radar to study the migration patterns of some bird species? It’s true, here are some links: Reflectivity loop from KTLX on May 5, 2018, showing a rapid increase of reflectivity after sunset commonly referred to as “bloom.” This likely contains both insects and migrating birds.Ĥ. Common dual-polarization signatures of birds are high differential reflectivity and low correlation coefficient. This motion frequently shows up as an expanding ring of reflectivity for a few scans around sunrise. Birds in the Morning Certain types of birds (purple martins are one of the most common) spend the night roosting in large flocks, and then they all take off in the morning to search for food. The following can help identify what kind of creatures are responsible for specific common patterns of biological echoes in radar data at certain times of the day or year. These types of echoes generally have low a correlation coefficient and high differential reflectivity. Dual-polarization data is usually the best way to distinguish biological echoes from precipitation, especially in a static image. In this second part of the series looking at common non-precipitation radar echoes, we will look at several examples of biological scatter, including birds, bats, and insects.