On the Impacts of Cloud Radiative Heating on General Circulation and Extreme Events

Indiana University, Bloomington IN

Investigators

Abstract

This project will train two graduate students. Both the dynamics-based diagnostic tools developed and data produced in the research project will be made publicly available via online repositories. The funded project will augment previously NSF-funded science outreach programs at Indiana University, including the Jim Holland Research Program which serves under-represented high school students throughout Indiana. The research team will partner with WonderLab, a local museum for Science, Health, and Technology, and local school districts to create and disseminate climate change modules, thereby enhancing Indiana Science Teaching Standards in local K12 classrooms. The results from the research project will be widely disseminated in conferences and peer reviewed publications. Clouds and the associated precipitations are products of storms of various sizes ranging from a few kilometers to few thousand kilometers. In extratropics, particularly in winter seasons, clouds and precipitations are produced mainly by cyclones or storms that are few thousand kilometers wide. These large-scale storms are organized by mid-latitude westerly jet stream meandering meridionally along the latitude circle and tend to amplify over the North Pacific and North Atlantic off the east coasts of the two major continents. Latent heating release occurring during the formation of clouds and precipitations is known to play a critical role in the rapid amplification and lengthening of the life cycle of these storms. Besides releasing latent heat, clouds also alter atmospheric radiative heating profile by absorbing thermal energy emission from the surface and atmosphere below that are warmer while radiating heat out at a colder temperature, as well as reflecting more incoming solar energy back to space that causes cooling at the surface. Cloud-induced radiative heating anomalies may have long-lasting effect not only on the development of these storms but also on the westerly jet stream that carries them, as cyclones tend to preferentially amplify or redevelop over certain longitude sections in mid-latitudes, such as the North Pacific and North Atlantic. This research will diagnose how radiative heating anomalies associated with clouds affects the westerly jet and Rossby waves in which cyclones that produce clouds are embedded. Specifically, the research team will calculate 3D cloud-induced radiative heating rate anomalies in mid-latitudes using observational datasets and modeling output. They will examine the contribution from such anomalies to the low-frequency variability of the westerly jet stream and large-amplitude long-lasting atmospheric circulation anomalies, such as blocking flow. 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.