Discontinuities found in ISIMIP3a climate input data #2


Iliusi Vega del Valle reported on March 31, 2021.
Unfortunately, the bias-adjustment problem identified in ISIMIP3b [1] also affects the observational climate forcings provided in ISIMIP3a. There, the bias adjustment method is applied to adjust GSWP3, ensuring a smooth transition to W5E5 in the combined forcing dataset GWSP3-W5E5. For the period 1901-1978, this adjustment introduces similar jumps in the seasonal cycle as found in the bias-adjusted GCM data; see the multi-year daily mean value plots for all Giorgi regions in [2].

The same problem exists in the original GSWP3 data. As this dataset is provided externally, the ISIMIP team cannot fix it alone. Hence they are currently exploring different options of how to backward-extend the W5E5 dataset, for the case that the discontinuities in GSWP3 cannot be removed.

Therefore both the ISIMIP3b bias-adjusted climate input data, and the ISIMIP3a observational and counterfactual climate input datasets (both GSWP3-W5E5 and GSWP3) will be updated. More information on planned updates for these datasets in [3].

On 21 Oct 2021, the GSWP3-W5E5 dataset was replaced by a newer version based on GSWP3 v1.09 and W5E5 v2.0 along with the ISIMIP3BASD v2.5.0 bias adjustment method. See comments below and [4] for details. This does not resolve this caveat.

[1] https://www.isimip.org/gettingstarted/input-data-changelog/isimip3b-discontinuities-found-bias-adjusted-climate-input-data/
[2] https://www.isimip.org/files/plots/inputdata/ISIMIP3a/annual_cycle/png_united/
[3] https://www.isimip.org/gettingstarted/input-data-changelog/isimip3a-discontinuities-found-climate-input-data/
[4] https://www.isimip.org/gettingstarted/input-data-changelog/isimip3a-climate-input-data-update/
Iliusi Vega del Valle commented on April 19, 2021.
Updates are expected to become available soon, hopefully by mid May 2021. Stay tuned.
Matthias Büchner commented on Jan. 6, 2022.
GSWP3 has been removed from the protocol and is not available for download anymore. As a replacement another input data set for ISIMIP3a is being worked on.

GSWP3-W5E5 was replaced by a newer version based on GSWP3 v1.09 and W5E5 v2.0 along with the ISIMIP3BASD v2.5.0 bias adjustment method.


Please use the replaced datasets for new simulations or research.

Severity high

Status resolved

before 20210126
Data product
Input Data
Input category
Climate related forcing
Input subcategory
Atmospheric forcings
Climate forcing
Climate experiment
counterclim, obsclim, spinclim
Climate variable
hurs, huss, pr, ps, rlds, rsds, sfcwind, tas, tasmax, tasmin
Simulation round

Affected datasets

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