Collaborative Research: Observing and Understanding Planetary Boundary Layer (PBL) Heterogeneities and Their Impacts on Tornadic Storms during VORTEX-SE 2018 Field Experiment

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High-impact weather phenomena such as high winds, hail, and heavy rainfall have huge socio-economic impacts. However, forecast for severe high-impact weather events, especially tornadoes, remains challenging. Historically, tornado research has been concentrated in the Great Plains while the Southeastern U.S. commonly experiences devastating tornadoes as well. Significant differences in environmental conditions over the two regions and frequent occurrence of tornadoes at night in the Southeast (SE) pose challenges to observing and understanding the formation and development of tornadoes in the SE. The Verification of the Origins of Rotation in Tornadoes Experiment - Southeast (VORTEX-SE) is a research program designed to understand how environments in the SE affect the formation, intensity, structure, and path of tornadoes in this region. During the VORTEX-SE field campaign in 2018, unprecedented advanced measurements from an airplane flying around tornadoes have been collected. Such observations cannot be done easily on the ground with hilly forest terrain. The study will utilize the unique observations and advanced computer models to understand airflow structures of tornadic storms and special environments for their formation. New knowledge gained from the research will contribute to improvement of tornado forecasting across the U.S. This project will provide support and training to graduate students in atmospheric measurement technologies, data analysis, and computer modeling and prepare them to become future scientists in severe weather research and prediction.The research team will conduct observational data analysis and advanced data assimilation that integrate observations and atmospheric prediction models. The unprecedented observation includes an advanced downward-pointing Compact Raman Lidar (CRL), a horizontally scanning lower fuselage (LF) radar, and dual Tail Doppler Radars (TDRs) onboard of a NOAA P-3 aircraft. The CRL is capable of measuring high-spatial and temporal resolution of water vapor, temperature, and aerosol profiles in the atmospheric boundary layer upstream of moving storms. Together with the P-3's in-situ measurements and the LF and TDR radar observations, unprecedented characterization of tornadic environments is expected. In addition, tornado-resolving numerical simulations will be performed, and variational, and ensemble-based data analysis and assimilation techniques will be applied. The primary goals of the project include: (1) characterization of spatial heterogeneities and temporal evolution of the PBL around convective storms in the VORTEX-SE domain with CRL measurements; (2) analysis and understanding of the impact of PBL heterogeneities on tornadic storms by synthesizing P-3 and other available observations; (3) identification and understanding of key physical processes involved in the tornadic storms through model simulations with advanced data assimilation methods. The synergy of airborne radar and lidar data with high-resolution model simulations will help pave the way for potentially transformative future process-oriented field experiments.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.