Year-end Sale % OFF 
Abstract
Tropical cyclones produce rainfall with extremely negative isotope values (δ18O and δ2H), but the controls on isotopic fractionation during tropical cyclones are poorly understood. Here we studied the isotopic composition of rainfall at sites across central Texas during Hurricane Harvey (2017) to better understand these processes. Rainfall δ18O trend towards more negative values as a result of Rayleigh distillation of precipitation-generating airmasses as they travel towards the center of the storm. Superimposed on these gradual changes are abrupt isotopic shifts with exceptionally low deuterium excess values. These appear to be controlled by microphysical processes associated with the passage of spiral rainbands over the sampling locations. Isotope-enabled climate modeling suggests that it may be possible to identify the signature of tropical cyclones from annually resolved isotopic proxy records, but will depend on the size of the storm and the proximity of the site to the core of the storm system.
Highlights
Tropical cyclones produce rainfall with extremely negative isotope values (δ18O and δ2H), but the controls on isotopic fractionation during tropical cyclones are poorly understood
We investigate the mechanisms of isotopic variability during Hurricane Harvey (2017) using rainwater collected in Austin, San Antonio, and Houston
We demonstrate that event-long trends in rainfall δ18O values are predominantly controlled by upstream rainout and Rayleigh distillation along the moisture transport pathway
Summary
Tropical cyclones produce rainfall with extremely negative isotope values (δ18O and δ2H), but the controls on isotopic fractionation during tropical cyclones are poorly understood. Rainfall δ18O trend towards more negative values as a result of Rayleigh distillation of precipitation-generating airmasses as they travel towards the center of the storm Superimposed on these gradual changes are abrupt isotopic shifts with exceptionally low deuterium excess values. A consistent observation in many studies of TCs is that there is a systematic depletion of heavy isotopes in rainfall radially inward towards the center of the storm, with exceptionally negative delta values only occurring in areas close to the eyewall[2,3,8,9]. What causes this spatial isotopic pattern remains a subject of debate. The eye of Hurricane Harvey did not pass directly over our sampling locations, its spiral rainbands produced 2–3 days of rainfall over all three sites, allowing us to capture both long-term trends and high-frequency changes in precipitation isotope values and to evaluate the causes of these variations
Sign-in/Register to view highlights & summary 
Published Version (
Free)
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
