Sub‐Grid Representation of Vegetation Cover in Land Surface Schemes Improves the Modeling of How Climate Responds to Deforestation

• Published in: Geophysical research letters Vol. 50; no. 15
• Main Authors: Qin, Yingzuo, Wang, Dashan, Cao, Ye’er, Cai, Xitian, Liang, Shijing, Beck, Hylke E., Zeng, Zhenzhong
• Format: Journal Article
• Language: English
• Published: Washington John Wiley & Sons, Inc 16.08.2023; Wiley
• Subjects: Air temperature; Atmospheric models; Climate; Climate and weather; Climate models; Climate sensitivity; CLM; Deforestation; Deforestation effects; Evapotranspiration; land atmosphere interaction; Land cover; Massifs; Modelling; Plant cover; Precipitation; Precipitation-temperature relationships; Regional climates; Representations; Sensitivity; Simulation; subgrid; Surface temperature; Surface-air temperature relationships; Tiling; Vegetation; Vegetation cover; Weather; Weather forecasting; WRF
• ISSN: 0094-8276; 1944-8007
• DOI: 10.1029/2023GL104164

Understanding the regional climate response to land cover change requires a realistic sub‐grid representation of vegetation cover in the land surface scheme (LSS) of climate models. The Community Land Model (CLM) is considered one of the most advanced LSSs; however, when coupled with the Weather Research and Forecasting (WRF) model, the tiling vegetation cover approach was deactivated. Here, we reactivated the theoretical sub‐grid vegetation cover representation in WRF‐CLM and applied it to assess the impacts of deforestation on regional climate in the Southeast Asian Massif region. We found that CLM‐tiling performs more accurate simulations of surface air temperature and precipitation compared to other LSSs using the in situ observations. Importantly, CLM‐tiling successfully captures the theoretical sensitivity of evapotranspiration (ET) and temperature to sub‐grid deforestation, aligning with Noah‐mosaic, and it substantially improves the spatial pattern responses of simulated ET and temperature to regional deforestation. Plain Language Summary The selection of appropriate land surface schemes (LSSs) is crucial for studying land‐atmosphere interactions in the Weather Research and Forecasting (WRF) model. While most LSSs adopt a dominant vegetation cover approach, where each grid cell is assigned a single land cover type, only Noah‐mosaic can represent sub‐grid vegetation cover changes. However, several studies have mistakenly assumed that the default coupled Community Land Model (CLM) in WRF is capable of simulating such changes, which may have affected their conclusions. In this study, we modified the CLM‐default by reactivating the tiling vegetation cover approach (CLM‐tiling), which accurately represents sub‐grid vegetation cover changes. Our application of the CLM‐tiling in the Southeast Asian Massif region led to improved simulations of air temperature and precipitation compared to other LSSs. Moreover, we found that CLM‐tiling successfully exhibited theoretical climate sensitivity to sub‐grid forest loss, improving the spatial pattern responses of simulated evapotranspiration and temperature to regional deforestation. Key Points Default WRF‐CLM lacked theoretical sub‐grid vegetation cover representation, failing to capture climate response to sub‐grid deforestation CLM‐tiling could successfully capture the sensitivity of evapotranspiration and temperature to sub‐grid deforestation Involving sub‐grid vegetation cover representation in WRF‐CLM improved the spatial pattern responses of simulated climate to deforestation