Physics
Scientific paper
Dec 2004
adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2004agufm.p14a..01r&link_type=abstract
American Geophysical Union, Fall Meeting 2004, abstract #P14A-01
Physics
9325 Atlantic Ocean, 3374 Tropical Meteorology, 3314 Convective Processes, 0305 Aerosols And Particles (0345, 4801), 0365 Troposphere: Composition And Chemistry
Scientific paper
It has long been observed that the Saharan Air Layer (SAL), a large and seasonally-persistent layer of West African aeolian dust suspended over the Atlantic Ocean, may influence the variability and intensity of easterly waves and tropical cyclones in the Atlantic basin. The radiative and conductive properties of the Saharan aerosols may contribute to warming within the dust layer, creating an anomalous baroclinic zone in the tropical North Atlantic. Environmental baroclinic instability is a mechanism for conversion of potential energy to eddy kinetic energy, facilitating wave growth. However, this same baroclinic mechanism, along with the dry properties of the SAL, could also promote asymmetry in a tropical cyclone, limiting its intensity. Detailed investigations of specific cases are necessary to better understand the radiative heating or cooling impact that the Saharan aerosols cause as well as potential influences on cyclone track and intensity stemming from the aeolian dust cloud. Here, we consider the case of Claudette in 2003. On June 29, 2003, an easterly wave embedded near the southern boundary of a broad Saharan dust layer emerged from the West African Coastal Bend region into the Atlantic Ocean. The wave propagated westward, reaching tropical storm intensity as Claudette in the Caribbean and developing into a hurricane just before making landfall on the southern Texas Gulf of Mexico coast on July 15. The SAL propagated in phase with this system throughout almost its entire evolution. Rapid intensification of Claudette into a hurricane in the last 15 hours prior to landfall was concurrent with a decoupling from the Saharan dust intrusion, with the two following separate tracks into North America at the end of the period. We performed an investigation to understand and diagnose the interaction between the Saharan Air Layer and Claudette. HYSPLIT (Hybrid Single Particle Lagrangian Integrated Trajectory Model) along-trajectory potential temperature plots as well as the MODIS-TERRA (Moderate Imaging Spectroradiometer) aerosol product suggested that the intensity of Saharan dust was well correlated to heating in the environment. NOGAPS (Navy Operational Global Atmospheric Prediction System) model analysis outputs revealed that the mid-level easterly jet along the southern SAL boundary was a source for potential combined barotropic-baroclinic instability, possibly contributing to the growth of the formative easterly wave. The Charney-Stern condition was satisfied for the formative tropical wave throughout most of its evolution, corresponding to the mostly progressive wave growth occurring almost consistently throughout its evolution. The current research suggests that there was a dual-celled set of circulations, forced by the SAL boundaries, but modified by the mid-level easterly jet. The presence of the dust layer appears to have been a factor playing an important role in the life cycle of this tropical cyclone. In this case, the dusty Saharan Air Layer apparently facilitated growth of the formative easterly wave, but later suppressed the intensity of Claudette until shortly before landfall.
Chang Chulhoon
Gill T. E.
Rothman G. S.
No associations
LandOfFree
Saharan Air Layer Interaction with Hurricane Claudette (2003) does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Saharan Air Layer Interaction with Hurricane Claudette (2003), we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Saharan Air Layer Interaction with Hurricane Claudette (2003) will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-1646872