Trying to understand how a weather radar works
corsita | Premium last edited by
Few days ago I learned on this forum, that the “weather radar” is showing me data from a radar. Should not have been a surprise, since the word contains radar... But I always thought it was satellite data.
So I located the radar responsible for my whether display on Windy to be on a 148 meter high hill in Sattahip. Looking at a photo of the building, I estimate the focal point of the radar to be at approximately 18 meters. Makes the radar 166 meter over sea level. The horizon for the radar is in 46 kilometers distance. Everything beyond that it cannot see (sure: clouds are higher up). There is nothing in the line of sight to the horizon.
Since I am 190 kilometers away, it means that the radar is “looking” at 1627 meter over me. Doesn’t that quite falsify the result the further away one is from the radar? I am pretty sure the heavy rain zones that cross my location now during monsoon season are very much lower.
At the outer edge of its range (which is 240 kilometers) it is actually “looking” almost 3 kilometers over sea level. I have the impression it is sort of guessing what it looks down on the ground from what it sees at the height? Somebody knows how this data is being analyzed?
PS: sorry to the flaterthlers reading this. I am assuming the earth is a sphere ;-)
I am not a radar specialist but this article shows that radar beam is not in straight line on long distances: