Change in daily weather variability due to warming and regional aerosols.

The world has changed: You can feel it in the air as temperatures rise, you can feel it in the water as precipitation patterns change. Much of what has once been our daily weather is lost. It began with humankind emitting greenhouse gases and aerosols. However, there is a growing resistance that wants to limit theses emissions. 

Daily variability can be described by probability density functions (PDF). Change can manifest as changes of the mean properties of weather-related variables, and/or changes in the chape of their PDFs. In this study, we examine how regional PDF shapes change due to increasing temperature, driven primarily by greenhouse gas emissions, and due to emissions of different aerosols species (black carbon and sulfate). Our main questions are: (1) How do shapes of regional daily PDFs evolve with global warming? (2) How do these changes differ in response to aerosol and greenhouse gas emissions? (3) And which aerosol-related teleconnections induce these changes in PDF shapes?  As changes in shape affect low and high extremes differently, we aim to link changes in PDF shape to changes in extreme events of daily temperature and precipitation by using parameters describing PDF width and asymmetry.

We use data from PDRMIP single forcer climate model simulations to examine how changes in regional and global aerosol concentrations change the PDF shapes. We also use three CMIP6 large ensembles (MPI-ESM1-2-LR, CanESM5 and ACCESS-ESM1-5) to examine changes in PDF shape at five different levels of global warming, from 1°C to 4 °C. Our main questions are how the shapes of regional daily PDFs evolve with globalwarming, how their changes differ between aerosol and greenhouse gas induced changes, and what teleconnections due to regional aerosol changes induce in PDF shapes.

For the time will soon come when aerosols will shape the near future of our weather.