Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Misrepresentation of the number of precipitation events #127

Open
TanguiP opened this issue Apr 1, 2022 · 1 comment
Open

Misrepresentation of the number of precipitation events #127

TanguiP opened this issue Apr 1, 2022 · 1 comment

Comments

@TanguiP
Copy link

TanguiP commented Apr 1, 2022

Hello,

I am using xesmf to interpolate (conservative interpolation) precipitation products from their native grid to a common one for comparison purpose. However, I have recently found something odd. I am comparing precipitation frequency at each grid point (I.e. the number of non-null precipitation) and the interpolation failed to recreate this characteristic of the precipitation.
For a dataset and a variable called ds_1 and precipitation_3h, the frequency is given by the command: ds_1.precipitation_3h.where(ds_1.precipitation_3h>0).count(dim="time")
The following graphic show the mean precipitation (left) and the frequency (right) of the same precipitation estimate before (down) and after (up) interpolation.

IMERG_inter

Input grid (resolution 0.1°)
<xarray.Dataset>
Dimensions: (lat: 50, lon: 50, time: 248)
Coordinates:

  • lon (lon) float32 290.0 290.1 290.2 ... 294.8 294.9 295.0
  • lat (lat) float32 30.05 30.15 30.25 ... 34.75 34.85 34.95
  • time (time) datetime64[ns] 2015-01-01 ... 2015-01-31T21:00:00
    Data variables:
    precipitation_3h (lat, lon, time) float32 0.03335 0.03451 ... 0.0 0.5153

Output grid (resolution of 0.25°)
<xarray.Dataset>
Dimensions: (lat: 19, lat_b: 20, lon: 19, lon_b: 20)
Coordinates:
k float64 0.1265

  • lon (lon) float32 290.2 290.5 290.8 291.0 ... 294.0 294.2 294.5 294.8 (resolution of 0.25)
  • lon_b (lon_b) float64 290.1 290.4 290.6 290.9 ... 294.1 294.4 294.6 294.9
  • lat (lat) float32 30.25 30.5 30.75 31.0 31.25 ... 34.0 34.25 34.5 34.75
  • lat_b (lat_b) float64 30.12 30.38 30.62 30.88 ... 34.12 34.38 34.62 34.88

I’ve tried to use other interpolation methods without success. Can you tell me if it is my fault, or this is a limit of the interpolation method?
Regards,
Tangui

@raphaeldussin
Copy link
Contributor

This version of the package is no longer maintained. Would you mind moving your issue to https://github.com/pangeo-data/xESMF?

Sign up for free to join this conversation on GitHub. Already have an account? Sign in to comment
Labels
None yet
Projects
None yet
Development

No branches or pull requests

2 participants