Preprints
https://doi.org/10.5194/egusphere-2025-4149
https://doi.org/10.5194/egusphere-2025-4149
02 Sep 2025
 | 02 Sep 2025
Status: this preprint is open for discussion and under review for Biogeosciences (BG).

Land Surface Model Underperformance Tied to Specific Meteorological Conditions

Jon Cranko Page, Martin G. De Kauwe, Andy J. Pitman, Isaac R. Towers, Gabriele Arduini, Martin J. Best, Craig Ferguson, Jürgen Knauer, Hyungjun Kim, David M. Lawrence, Tomoko Nitta, Keith W. Oleson, Catherine Ottlé, Anna Ukkola, Nicholas Vuichard, and Gab Abramowitz

Abstract. The exchange of carbon, water, and energy fluxes between the land and the atmosphere plays a vital role in shaping our understanding of global change and how climate change will affect extreme events. Yet our understanding of the theory of this surface-atmosphere exchange, represented via land surface models, continues to be limited, highlighted by marked biases in model-data benchmarking exercises. Here, we leveraged the PLUMBER2 dataset of observations and model simulations of terrestrial fluxes from 153 international eddy-covariance sites to identify the meteorological conditions under which land surface models are performing worse than a priori expectations. By defining performance relative to three sophisticated out-of-sample empirical models, we generated a lower bound of performance in turbulent flux prediction that can be achieved with the input information available to the land surface models during testing at flux tower sites. We found that land surface model (LSM) performance relative to empirical models is worse at boundary conditions – that is, LSMs underperform in timesteps where the meteorological conditions consist of coinciding relative extreme values. Conversely, LSMs perform much better under "typical" conditions within the centre of the meteorological variable distributions. Constraining analysis to exclude the boundary conditions results in the LSMs outperforming strong empirical benchmarks. Encouragingly, we show that refinement of the performance of land surface models in these boundary conditions, consisting of only 12 % to 31 % of time steps, would see large improvements (22 % to 114 %) in an aggregated performance metric. Precise targeting of model development towards these meteorological boundary conditions offers a fruitful avenue to focus model development, ensuring future improvements have the greatest impact.

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Jon Cranko Page, Martin G. De Kauwe, Andy J. Pitman, Isaac R. Towers, Gabriele Arduini, Martin J. Best, Craig Ferguson, Jürgen Knauer, Hyungjun Kim, David M. Lawrence, Tomoko Nitta, Keith W. Oleson, Catherine Ottlé, Anna Ukkola, Nicholas Vuichard, and Gab Abramowitz

Status: open (until 14 Oct 2025)

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Jon Cranko Page, Martin G. De Kauwe, Andy J. Pitman, Isaac R. Towers, Gabriele Arduini, Martin J. Best, Craig Ferguson, Jürgen Knauer, Hyungjun Kim, David M. Lawrence, Tomoko Nitta, Keith W. Oleson, Catherine Ottlé, Anna Ukkola, Nicholas Vuichard, and Gab Abramowitz

Model code and software

Analysis Code for "LSM Underperformance Tied to Specific Meteorological Conditions" Jon Cranko Page https://github.com/JDCP93/LSMUnderperformance

Jon Cranko Page, Martin G. De Kauwe, Andy J. Pitman, Isaac R. Towers, Gabriele Arduini, Martin J. Best, Craig Ferguson, Jürgen Knauer, Hyungjun Kim, David M. Lawrence, Tomoko Nitta, Keith W. Oleson, Catherine Ottlé, Anna Ukkola, Nicholas Vuichard, and Gab Abramowitz
Metrics will be available soon.
Latest update: 02 Sep 2025
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Short summary
This paper used a large dataset of observations, machine learning predictions, and computer model simulations to test how well land surface models represent the water, energy, and carbon cycles. We found that the models work well under "normal" weather but do not meet performance expectations during coinciding extreme conditions. Since these extremes are relatively rare, targeted model improvements could deliver major performance gains.
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