The role of clouds in climate change

Earth's climate is changing. Reliable climate predictions are essential for developing climate change mitigation and adaptation strategies, and thus have a significant socio-economic value. However, climate predictions are still highly uncertain due largely to our limited understanding of the role of clouds in climate change. The challenge in understanding clouds' role in climate change stems mostly from a scale separation between the cloud or cloud field scale (10² - 10⁴ m) to the global climate scale (>10⁶ m). Despite this scale separation, clouds and the climate system are strongly coupled. Accounting for this large range of scales in a single research framework is considered the "holy grail" of our research field. Our main research goal is to develop innovative setups that account simultaneously for cloud scale processes and for changes in the large-scale tropical circulation. Using these setups, we examine the clouds' response to anthropogenic perturbations and specifically the co-variability, compensations and interactions between different cloud regimes, which are connected by the large-scale atmospheric circulation. Our aim is to connect local cloud/cloud field scale anthropogenically driven perturbations to the larger climate scale.

Aerosol effect on clouds and precipitation

Under climate change, in addition to the expected changes in surface temperature, precipitation is also expected to change, with potentially significant implications for society. A main driver for precipitation changes are anthropogenic aerosols (tiny solid or liquid particles suspended in the atmosphere, which were realised due to human activity). By interacting with radiation, and by affecting cloud properties, aerosols perturb precipitation amount. We use reginal and global numerical simulations of varies levels of complexity to better understand the aerosol microphysical and radiative effects on clouds and precipitation.