Get U/V windspeeds over time at a single grid point

[jacob-roth]

Hi! I came across Herbie from HRRR while trying to collect windpseed data at a single location over time. Is this possible to do in Herbie? I'm new to the 2D latlon coordinates referenced here and was wondering if there would be an easy way of gathering windspeed data (at a particular mb pressure) over time at a single location, e.g., near Minneapolis. (The example referenced in a previous discussion here doesn't show up for me) Thanks!

[blaylockbk]

Hi @jacob-roth. Thanks for your question.
Getting the nearest points from a curvilinear grid is not a trivial task. One disadvantage of the GRIB format is that individual points can't be downloaded from the grid--the full grid has to be downloaded, then you can pluck out the point you want. I do have a method in Herbie that I think works pretty well; it's implemented as an xarray custom accessor.

Download a timeseries of Data, only getting the U and V winds at 500 mb.

import pandas as pd
from herbie import Herbie, fast_Herbie_xarray

DATES = pd.date_range('2022-05-25', periods=6, freq='1H')

ds = fast_Herbie_xarray(
    DATES=DATES, 
    searchString='(?:U|V)GRD:500 mb', 
    model='hrrr', 
    product='prs', 
    fxx=0
)

Get the nearest point to Minneapolis

minneapolis = (-93.25, 44.98) # (lon, lat)
ds_at_point = ds.herbie.nearest_points(points=minneapolis)
ds_at_point = ds_at_point.squeeze() # I did squeeze because we only requested one point

Make a plot of the timeseries

ds_at_point.u.plot(label='u', marker='.')
ds_at_point.v.plot(label='v', marker='.')
plt.legend()

I plotted the latitude/longituge of the nearest point on a map.
It was (-93.262, 44.969) which is pretty close to the requested point.

[blaylockbk]

If you need lots of wind data at a point, the Herbie implementation can be inefficient due to the limitation of the GRIB format. The HRRR dataset is available in Zarr format, and that provides a more efficient way to get values at a specific point (https://mesowest.utah.edu/html/hrrr/zarr_documentation/)