| Autor: |
Liu, Shu, Han, Yilun, Wang, Peng, Zhang, Guang J., Wang, Bin, Wang, Yong |
| Předmět: |
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| Zdroj: |
Geophysical Research Letters; 7/16/2024, Vol. 51 Issue 13, p1-9, 9p |
| Abstrakt: |
Current global climate models (GCMs), limited to grid‐scale land‐atmosphere coupling, cannot represent subgrid urban‐rural precipitation contrasts. This study develops an innovative two‐way subgrid land‐atmosphere coupling framework in the National Center for Atmospheric Research (NCAR) Community Earth System Model version 2 (CESM2) to explicitly resolve land‐atmosphere interaction over subgrid individual land units. Results show that urban heat island (UHI) leads to the urban rainfall effect (URE), which in turn alleviates overestimated UHI over China in CESM2. The URE manifests as a shift toward more heavy precipitation and less light precipitation in world urban areas than in surrounding rural counterparts. This feature is consistent with available observations. In heavy precipitation situations, the UHI promotes atmospheric instability and enhances atmospheric water vapor holding capacity, resulting in more heavy precipitation in urban areas. Conversely, in light precipitation situations, the UHI and decreased evaporation from urban impermeable surfaces diminish atmospheric relative humidity, suppressing light precipitation. Plain Language Summary: Given the grid‐scale land‐atmosphere coupling (operating at a scale of ∼100–200 km), all the current global climate models cannot represent precipitation over urban areas. This obstructs the explicit simulation and future projections of precipitation in world urban regions, where over half of the world's population resides and a substantial portion of economic activities occurs. To address this issue, this study develops a novel land‐atmosphere coupling framework that explicitly allows land‐atmosphere interaction over individual land units within the grid cell in global climate models. The modeling results show a greater daily average of precipitation intensities on precipitation days in urban areas than in rural areas due to urban warming, with a shift toward more heavy precipitation and less light precipitation. These findings indicate an escalation in the risk of extreme precipitation and flooding in urban regions around the globe, as urban land continues to expand. Key Points: A novel framework of two‐way subgrid land‐atmosphere coupling for GCMs is developed and implemented in CESM2Overestimated urban heat island over China in CESM2 is significantly alleviated by explicitly representing urban rainfall effectsWorld urban regions feature more heavy precipitation and less light precipitation than the surrounding rural areas [ABSTRACT FROM AUTHOR] |
| Databáze: |
Complementary Index |
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