3A.4 Exploring Radiative Influence on Extratropical Cyclone Development and Sensitivity

Monday, 7 January 2019: 2:45 PM
North 121BC (Phoenix Convention Center - West and North Buildings)
Gregory Tierney, North Carolina State Univ., Raleigh, NC; and D. J. Posselt and J. F. Booth

Extratropical cyclones (ETCs) are some of the most influential drivers of synoptic-scale variability in the midlatitudes, providing the majority of precipitation in many of the planet’s most populated regions. They are also responsible for numerous high-impact weather events such as wind storms, extreme rain, and heavy snowfall, leading to property damage, transportation disruptions, and economic losses. From a more wide-scale meteorological perspective, ETCs also serve as key conduits regulating the flow of energy, momentum, and moisture between the equator and poles. Because of their intermediate size, ETCs are still strongly influenced by their developmental environment, the characteristics of which are projected to change substantially in the coming decades. As the cyclogenetic environment evolves, impacts on the developing ETC occur not only through direct drivers such as changes to temperature, moisture content, and baroclinicity (many of which have been well-studied in the current literature) but also indirect feedback loops, which have received less attention.

This work examines one of those feedback loops -- the effect of radiative processes on ETC development and sensitivity, using the idealized mode of the Weather Research and Forecasting model (WRF), and is divided into two main focus areas. First, we focus on radiative processes as a standalone influence on ETC development, reviewing a four-experiment suite spanning simulations with radiative processes fully enabled to fully disabled, including two semi-radiative runs which disable radiative interactions with clouds and atmospheric water vapor. Second, we consider how the inclusion of radiative processes might amplify or diminish ETC sensitivity to the aforementioned direct drivers of ETC structure. In doing so, we achieve a fuller picture of the interplay between ETCs and their developmental environment by elucidating the roles of individual physical processes.

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