This page should describe Validation Tests performed for this stand alone feature and should provide links to all the result pages.

Summary

Global offline simulations were performed using the ICNPRDCTCBC compset with and without variable soil thickness.

Validation Test 1

Validation Test 1: Comparison of CTC pools with and without variable soil thickness

Date last modified: August 13, 2020

Contributors: Michael Brunke

Provenance: ICNPRDCTCBC in mabrunke/lnd/varsoil-in-ZD2009-with-BGC vs. master

Results: (link to results, data and plots)

There are large effects to adding variable soil thickness in carbon and nitrogen pools, particularly for depth-to-bedrock (DTB) < 5 m. There is also some increased spread in total ecosystem nitrogen for DTBs > 22 m. Near-zero differences occur in grid cells receiving precipitation > 5 mm/day, so the larger differences arise in drier grid cells. Therefore, variable soil thickness can have a substantial impact on BGC simulated in dry locations.

Figure 1. The difference in total carbon, nitrogen, and phosphorus pools between simulations with and without variable soil thickness as a function of depth-to-bedrock. Positive values mean larger amounts with variable soil thickness.

Validation Test 2

Validation Test 2: Comparison of basin TWS to GRACE

Date last modified: August 21, 2020

Contributors: Michael Brunke

Provenance: ICNPRDCTCBC in mabrunke/lnd/varsoil-in-ZD2009-with-BGC vs. master

Results: (link to results, data and plots)

Basin mean total water storage (TWS) anomalies for the last 13 years from the two ICNPRDCTCBC simulations (CONTROL without and VARSOIL with variable soil thickness) are compared to those from GRACE for 2002-2014 in nine river basins. There are small differences between the two simulations. Both simulations have smaller annual cycles than in GRACE, but, despite this, the model anomalies are similar to the GRACE anomalies in all basins except the Amazon. The lower annual cycles could be due to the nature of the ICNPRDCTCBC simulations which are forced by a repeating 2000 annual cycle. The evaluation of a transient run will be analyzed in the future for publication.

Figure 2. Time series in basin mean total water storage (TWS) anomalies for 13 years (2002-2014 for GRACE compared to the last 13 years in the simulations). There are three different TWS retrievals based on spherical harmonics from GRACE measurements from the Center for Space Research (CSR) at The University of Texas at Austin, GeoForschungsZentrum (GFZ) Potsdam, and the Jet Propulsion Laboratory (JPL).

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