As the global temperature increases with changing climate, precipitation rates and patterns
are affected through a wide range of physical mechanisms. The globally averaged intensity of
extreme precipitation also changes more rapidly than the globally averaged precipitation rate.
While some aspects of the regional variation in precipitation predicted by climate models
appear robust, there is still a large degree of inter-model differences unaccounted
for. Individual drivers of climate change initially alter the energy budget of the
atmosphere leading to distinct rapid adjustments involving changes in precipitation.
Differences in how these rapid adjustment processes manifest themselves within models
are likely to explain a large fraction of the present model spread and needs better
quantifications to improve precipitation predictions. Here, we introduce the Precipitation
Driver and Response Model Intercomparison Project (PDRMIP), where a set of
idealized experiments designed to understand the role of different climate forcing
mechanisms were performed by a large set of climate models. PDRMIP focuses on
understanding how precipitation changes relating to rapid adjustments and slower responses
to climate forcings are represented across models. Initial results show that rapid
adjustments account for large regional differences in hydrological sensitivity across
multiple drivers. The PDRMIP results are expected to dramatically improve our
understanding of the causes of the present diversity in future climate projections. |