Assessment of a tiling energy budget approach in a land surface model, ORCHIDEE-MICT (r8205)

• Published in: Geoscientific Model Development
• Main Authors: Y. Xi, C. Qiu, Y. Zhang, D. Zhu, S. Peng, G. Hugelius, J. Chang, E. Salmon, P. Ciais
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2024
• Subjects: Geology; QE1-996.5; permafrost
• Online Access: https://doi.org/10.5194/gmd-17-4727-2024; https://doaj.org/article/3f61e62eb90a4594a09d8448864f30a8

The surface energy budget plays a critical role in terrestrial hydrological and biogeochemical cycles. Nevertheless, its highly spatial heterogeneity across different vegetation types is still missing in the ORCHIDEE-MICT (ORganizing Carbon and Hydrology in Dynamic EcosystEms–aMeliorated Interactions between Carbon and Temperature) land surface model. In this study, we describe the representation of a tiling energy budget in ORCHIDEE-MICT and assess its short-term and long-term impacts on energy, hydrology, and carbon processes. With the specific values of surface properties for each vegetation type, the new version presents warmer surface and soil temperatures ( ∼ 0.5 °C , + 3 %), wetter soil moisture ( ∼ 10 kg m −2 , + 2 %), and increased soil organic carbon storage ( ∼ 170 Pg C , + 9 %) across the Northern Hemisphere. Despite reproducing the absolute values and spatial gradients of surface and soil temperatures from satellite and in situ observations, the considerable uncertainties in simulated soil organic carbon and hydrological processes prevent an obvious improvement in the temperature bias existing in the original ORCHIDEE-MICT model. However, the separation of sub-grid energy budgets in the new version improves permafrost simulation greatly by accounting for the presence of discontinuous permafrost types ( ∼ 3×10 6 km 2 ), which will facilitate various permafrost-related studies in the future.