Speaker
Description
Landscape diversity can influence cloud development by modifying evapotranspiration, surface roughness, turbulent mixing and boundary-layer growth. However, the strength of this land-surface influence depends on whether clouds are thermodynamically connected to the surface. This ongoing study investigates how landscape and land-cover structure relate to coupled and decoupled cloud states over Southern Germany. We combine MODIS Aqua cloud observations, ERA5 surface meteorology, CORINE land-cover data, GEDI vegetation structure and elevation information for May 2019-2022. Cloud-surface coupling is diagnosed at the MODIS overpass scale. For each valid liquid-cloud pixel, MODIS cloud top pressure, cloud top temperature and liquid water path are used to estimate cloud base through an adiabatic liquid-water-path integration. From cloud base, an air parcel is extrapolated dry-adiabatically to ERA5 surface pressure. The resulting adiabatic surface temperature is compared with ERA5 2 m temperature; positive differences indicate coupled clouds, while negative differences indicate decoupled clouds. Preliminary results show that liquid clouds over Southern Germany are predominantly decoupled in May, although coupled and decoupled states occur as spatially coherent patches within individual cloud scenes. Monthly coupled fractions increase from 18.7% in 2019 to 26.8% in 2022, suggesting interannual variability in cloud-surface thermodynamic connection. The next phase will use statistical and machine-learning models to quantify relationships between vegetation structure, land-cover type, elevation and cloud coupling state. We will test whether forest cover, canopy height, canopy heterogeneity and land-cover classes are associated with differences in coupled fraction, decoupled fraction, cloud-top temperature and liquid water path. By linking cloud thermodynamic state with ecosystem structure, this work contributes to a scale-explicit understanding of how vegetation may shape land-atmosphere functioning.
| Status Group | Doctoral Researcher |
|---|---|
| FOR TALKS: Poster Presentation Option | Yes, I’m willing to present as a poster. |