Moisture source changes of precipitation in Europe under SSP1-2.6 and SSP3-7.0 warming

When global temperature increases, the atmosphere will be able to hold more water,
as described by the Clausius-Clapeyron equation. It is thus hypothesised that the global
water cycle will intensify under a warming climate. This might lead to more intense and more
frequent extreme precipitation events and might also affect the atmospheric circulation.
This project investigates how moisture sources of precipitation over the European
continent will change under SSP1-2.6 and SSP3-7.0 warming, using the atmospheric
general circulation model ECHAM6-wiso. A present day simulation (1990-2020), nudged to
ERA5 reanalysis, and a future simulation for each investigated SSP (2070-2099), nudged to
respective CMIP6 coupled model output, are conducted. Using numerical water tracers, the
model is able to trace precipitation back to its point of evaporation, characterised by latitude
and longitude.
Our results suggest that, under warming, the source latitude and longitude of
precipitation in Europe will change across all seasons. The magnitude of change depends
on the strength of the warming. These changes in source latitude and longitude reflect
changes in the mid-latitude wind patterns and atmospheric circulation.