Radar Data for specific location

[mhoster83]

Dear Weather Community,
my target is, to get a forecast for my home location, indicating if it rains or it will start to rain in 15 or 30 minutes.
I understood that this data can be retrieved from the radar images and that those have 900 x 900 pixels.
Does anyone know, how I could extract the color of one specific pixel (e.g. 230, 450), for the current time + 15 minutes and + 30 minutes.
Any help is highly appreciated.
Thanks

[gutzbenj]

Dear @mhoster83 ,

first of all thanks for reporting this possible usecase!

At first glance it may be easier to use Mosmix for the nearest station for this case (it already contains a parameter precipitation probability).

If you want to use radar data instead the product you are looking for is RADVOR. I haven't yet dealt with the consumption of such data however @kmuehlbauer is the expert and also the developer of wradlib. Kai, can you assist on this case?

Also after a quick look, you may use some code snippets from this example [1]

[1] https://docs.wradlib.org/en/stable/notebooks/zonalstats/wradlib_zonalstats_quickstart.html

[mhoster83]

Great, I will definitely look into this. Any further hint is appreciated.

[guidocioni]

As @gutzbenj said the radar forecast product RADVOR is the way to go,. in order to extract the information of 1 pixel you just have to read the data and then find the nearest grid point to the couple of lat lon that you're at. With xarray it's a matter of 1 line :)
I would suggest to use wradlib to read the data.
I have an application which does exactly what you want but even more complicated, that is computes the forecast of rain according to radar data projected on a bike ride, so many points in space and time. But the main concept is the same so maybe it will help you .. https://github.com/guidocioni/no-more-wet-rides-new

you can have a quick look at the demo here hh.guidocioni.it/nmwr

[kmuehlbauer]

@mhoster83 I would suggest doing that using the new xarray representation of the radolan reader in wradlib as @guidocioni suggested. Then you would be able to use xarray machinery to do all kinds of selections/interpolations etc.

@guidocioni Cool app! 💯 Do you think the point extraction code could be generalized to also work on high resolution single radar polar coordinate data?

@gutzbenj Zonalstats can also be used, but might be a bit of overkill for this use case. In general zonalstats is targeted to river catchment analysis.

[mhoster83]

Thank you very much for the helpful tips and ideas for a realization. I will try them an will give you an update.

[guidocioni]

@kmuehlbauer as long as you can translate polar coordinates into lat/lon it should not be a problem. Otherwise you could still extract it somehow....
In order to be as generic as possible my algorithm uses a K-d tree to find the closest radar grid point for every trajectory point, but in case you have a single coordinate pair the solution is overkill