Exploring New Satellite Technology for Extratropical Cyclone and Surface Heat Flux Analysis

Extratropical Cyclones;Surface Heat Fluxes;Remote Sensing;Boundary layer;Atmospheric;Oceanic and Space Sciences;Science;Atmospheric, Oceanic & Space Science

Crespo, JuanKeppel-Aleks, Gretchen ;

University of Michigan

关键词: Extratropical Cyclones;    Surface Heat Fluxes;    Remote Sensing;    Boundary layer;    Atmospheric;    Oceanic and Space Sciences;    Science;    Atmospheric, Oceanic & Space Science;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/143900/crespoj_1.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Extratropical cyclones play a large role in every day weather and Earth’s general climate, as they not only transport energy and moisture between the lower and higher latitudes, but also are associated with many extreme weather events observed across the globe. Throughout the winter of 2017 and 2018, we have already seen the impact extratropical cyclones have here in the United States. In December 2017, an extratropical cyclone brought snow as far south as Louisiana, and dumped up to six inches throughout Mississippi and Alabama. One month later, the nation was captivated as a ;;bomb cyclone” developed in the western Atlantic Ocean before making landfall in New England, causing blizzard conditions and affecting travel in one of the busiest corridors in the United States. Given their importance, it is critical that we build an understanding of how these systems develop at all scales, as well as surface processes involved in their genesis and evolution. While the scientific community has a good understanding of how extratropical cyclones develop at the synoptic scale thanks to nearly a century of research, there are still uncertainties when it comes to understanding how these systems develop at the mesoscale and microscale, as well as how surface processes could play a role in their development. This thesis offers a new understanding of how extratropical cyclones can develop by using existing and new satellite technologies that offer a unique analysis. For example, by using the existing NASA Afternoon-Train (A-Train) observations, we are able to observe a stratiform-to-convective transition within the warm front, something that had not been observed from a remote sensing platform before at this time. This fascinating transition raised more questions regarding how and why this transition occurred. One theory was the involvement of surface heat fluxes, as previous research has shown their influence on extratropical cyclone development. Given the importance of surface heat fluxes on not only marine-based extratropical cyclones, but also other weather phenomenon, it is important to consistently observe these fluxes. With the lack of in-situ measurements over the world’s oceans, spaceborne instruments need to be able to fill in this gap. By using the recently launched Cyclone Global Navigation Satellite System (CYGNSS), which offers improved estimates of surface wind speeds in nearly all weather conditions across the tropical and subtropical oceans, we can get better estimates of surface heat fluxes. While CYGNSS is a tropical mission, it is able to continuously observe extratropical cyclones that form in the lower latitudes, especially in areas where surface heat fluxes are strongest, such as off the coast of Japan and off the East Coast of the United States. This thesis highlights wind speed observations and surface heat flux estimates within and around some low-latitude extratropical cyclones that were observed in CYGNSS’s first year in orbit. These new CYGNSS observations offer a unique perspective of extratropical cyclone genesis and evolution, as this thesis lays the foundation for potential future satellite missions that aim to estimate surface heat fluxes from space.