Thermodynamic Modification of Winter Storms in a Warmer Climate

This award is funded in whole or in part under the American Rescue Plan Act of 2021 (Public Law 117-2).

Ice storms, which consist of freezing rain and/or ice pellets, are extraordinarily disruptive events that can cause hazardous travel conditions and power disruptions leading to economic losses and casualties. The impact of a changing climate on ice storms has not been thoroughly investigated, and it is complicated by how sensitive ice storms are to the temperature in the lower part of the atmosphere and at the surface.

This work will use an existing climate model simulation to address how freezing precipitation events could change in location, timing, and size in a warmer climate. The project has practical impact to decision-makers who may be dealing with questions about hardening of infrastructure. The researcher also plans an education and training aspect that ranges from high school to graduate students, ensuring the training of the next generation of scientists.

This award is for the study of freezing precipitation events, inclusive of ice pellets, freezing rain, and freezing drizzle, and how they may be altered with thermodynamics modifications consistent with late 21st century climate change. A key aspect of the project will be the use of the 4km resolution, hourly National Center for Atmospheric Research (NCAR) Weather Research and Forecast (WRF) model Pseudo Global Warming (PGW) simulation.

PGW is a technique where a model’s input and boundary conditions are modified by imposing a thermal change consistent with a warmer climate. High-resolution dynamical models for the examination of climate change are very computationally expensive, so the advantage of the WRF-PGW dataset is that it has already been conducted at a very high spatial and temporal resolution, with explicit convection and detailed documentation of biases and limitations.

Additional data sources include the NOAA Integrated Surface Database, gridded precipitation data, and reanalyses. Two main research questions are posed: 1) What is the distribution of winter storms of different synoptic ‘type’, and how does their contribution to the freezing precipitation climatology, intensity, and duration, change in a warmer climate versus the historical baseline, and 2) How does the structure, evolution, and morphology of winter storms change with late 21st century thermodynamic modification, including thermal and dynamic evolution, and distribution of precipitation phase within the system(s)?

This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.