Global Analysis of Characteristics of Tropical Easterly Waves and Related Precipitation

Hollis, Margaret

Global Analysis of Characteristics of Tropical Easterly Waves and Related Precipitation

dc.contributor.advisor	Martin, Elinor
dc.contributor.author	Hollis, Margaret
dc.contributor.committeeMember	Sakaea, Naoko
dc.contributor.committeeMember	Kirstetter, Pierre
dc.date.accessioned	2021-12-08T15:08:45Z
dc.date.available	2021-12-08T15:08:45Z
dc.date.issued	2021-12-17
dc.date.manuscript	2021-12
dc.description.abstract	Tropical easterly waves (TEWs) are important components of tropical convection and precipitation, especially in summer months. The most well-documented TEWs are African easterly waves (AEWs), which have been linked with rainfall variability and mesoscale convective systems in the Sahel region, as well as Atlantic tropical cyclone activity. TEWs in the Caribbean and eastern Pacific have also been shown to contribute to up to half of summertime rainfall in those regions. However, no global study of TEWs and their related precipitation exists. To fill this gap, we have created a global database of TEW tracks at both 850 and 700 hPa by using TRACK to identify regions of cyclonic curvature vorticity (CV) that meet thresholds for CV intensity, propagation direction and distance, and track length. In this database, we have identified 38723 TEW tracks throughout the entire tropics, with 14447 tracks at 850 hPa and 24276 tracks at 700 hPa. Globally and for each combination of level and hemisphere, the TEWs we identified have an average phase speed of 7.5 ms−1 and average propagation distance of 3000 km. In both hemispheres, there is a strong seasonal cycle, as well as interannual variability in TEW activity. Using these tracks and IMERG precipitation data, we found that TEWs can be associated with 20-30% of the total annual rainfall in regions with increased TEW activity and that TEWs with greater vertical coherence have more precipitation in the 500 km radius around the CV center. This global study on TEW activity and precipitation gives a global context to TEW behavior and importance across the tropics. In the future, these TEW tracks and their associated precipitation can also be used for additional studies on TEW lifecycles, interannual variability, and regional comparisons.	en_US
dc.identifier.uri	https://hdl.handle.net/11244/331416
dc.language	en_US	en_US
dc.subject	tropical easterly waves	en_US
dc.subject	climatology	en_US
dc.subject	precipitation	en_US
dc.thesis.degree	Master of Science in Meteorology	en_US
dc.title	Global Analysis of Characteristics of Tropical Easterly Waves and Related Precipitation	en_US
ou.group	College of Atmospheric and Geographic Sciences::School of Meteorology	en_US