Grants and Contributions:

Grant or Award spanning more than one fiscal year. (2017-2018 to 2022-2023)

The plains east of the Rockies are central to global grain production and known as the Breadbasket of the World. These regions are subjected to a high frequency of extreme rainstorms with summer flooding frequently associated with heavy precipitation generated by convective and synoptic weather systems. However the rainfall diurnal cycle especially the nighttime rainfall maximum observed over the plains is poorly understood. The eastward propagating of the convective systems is also largely under-represented in current numerical weather prediction models. Compared to the US Great Plains, the summertime diurnal precipitation over the Canadian Prairies is relatively unexplored.

My objectives are to address the following questions: 1) What are the dominant physical mechanisms that control the convection initiation, the peak time of the diurnal precipitation, as well as its systematic eastward propagation over the plains east of the Rockies in summer time? How can we incorporate these physical mechanisms to improve short-range, model-based forecasts of warm-season rainfall? 2) How can we appropriately reproduce the remote connection between the convection over the tropical western Pacific and the summer season precipitation over the Canadian Prairies in the model to improve the sub-seasonal climate prediction?

To achieve these goals, two PhD and one MSc students will be recruited to conduct comprehensive studies using field observations and remote sensing analysis, physical theory, as well as cutting-edge numerical modeling.

The two PhD students will work on understanding the convective mechanisms and the eastward propagation of the precipitation over the plains in warm season. Specifically, one will focus on testing our novel Potential Vorticity hypothesis and exploring the effects of surface processes such as evapotranspiration on diurnal convection and convection initiation. The other will focus on the forecasting model calibration.

The MSc student will investigate the remote influence of the convection over the tropical Pacific Ocean on the warm season precipitation over the Prairies. With the appropriate representation of the tropical coupled ocean–atmosphere dynamics, the forecasting model will be able to reproduce this remote connection appropriately.

This work will advance the weather and climate forecast of warm-season precipitation over the Canadian Prairies. The improved prediction has the potential to inform operational practice through translating precipitation to surface hydrology and flooding information. This will improve our ability in planning for water resources distribution, water supply changes and disaster management, which will further benefit regional agriculture and food security as well as ecosystem sustainability. All of which have significant economic consequences.