This project aims to estimate the change in frequency and intensity of Droughts ending in Intensified Precipitation - DRIP events with global warming due to changes in the water cycle. These compound events can cause greater damage to infrastructure and crops than single droughts or heavy precipitation events, as flooding and runoff are amplified by the hardened, dry ground.
In this project, we will identify historical DRIP events and assess how well they are represented in both observations and in reanalysis, in order to study how they are represented in models. A recently published study from the project looked at change in compound events in Europe where droughts end in heavy precipitation. Here we use regional climate models and show that there is 35% increase in DRIP events during summer months with an intermediate emission scenario and up to 75 % increase with a high emission scenario. There is, however, a large uncertainty, primarily due to the large variability in how droughts in model projections.
Further in the project we will analyze the occurrence of DRIP events in global climate models. As global climate models show a large spread in precipitation for both historical and the different future climate projections, there is expected to be a spread in model projections of DRIP events as well. We will constrain this spread by identifying global climate models that do a good statistical representation of historical DRIP events and by analyzing large ensembles to evaluate the natural variability. We will also perform in-house regional simulations of identified global models down to convection permitting scale to study the change in DRIP events with model resolution. The project will also target a highlighted uncertainty connected to the water-cycle by exploring how evapotranspiration and the occurrence of DRIP events found in climate models respond to land use change. For this analysis we will extend the regional downscaling to include sensitivity studies which contain deforestation and forestation. Results gained from DRIP will make a large contribution to the knowledge needed on future mitigation measures due to the increase in compound events.
Global warming intensifies drought and extreme precipitation. Compound events with droughts ending in intensified precipitation - DRIP can cause large damages but are extremely understudied. This project aims to estimate the change in frequency and intensity of DRIP events with global warming due to changes in the water-cycle. We will identify actual historical compound DRIP events and find indices that are suitable to identify these events in model data. As global climate models show a large spread in precipitation for both historical and the different future climate projections, there is expected to be a spread in model projections of DRIP events as well. We will constrain this spread by identifying global climate models that do a good statistical representation of historical DRIP events and by analyzing large ensembles to evaluate the natural variability. As higher resolution modelling shows a better representation of the water cycle, the project will analyze regional downscaled global models in identified regions of interest. We will also perform in-house regional simulations of identified global models down to convection permitting scale to study the change in DRIP events with model resolution. The project will also target a highlighted uncertainty connected to the water-cycle by exploring how evapotranspiration and the occurrence of DRIP events found in climate models respond to land use change. For this analysis we will extend the regional downscaling to include sensitivity studies which contain deforestation and forestation. Results gained from DRIP will make a large contribution to the knowledge needed on future mitigation measures due to the increase in compound events.
