Hurricanes Smoking Guns of Climate Change or random occurrences?
Dec 20, 2015
Hurricane Attributes
• A Central Pressure• A hurricane wind radius (quite variable)
• A duration• A location• An evolutionary timescale (spin up times)
• A total power at landfall• Need to link all of these together
Emily Chi Thesis
Atlantic Hurricane Formation
Low pressure centers form over Sahara desert and may get amplified as they cross open ocean
Amplification depends critically on SST and available moisture in the atmosphere
Must also have favorable wind conditions (light winds aloft) and weak wind shear
Hurricane Frequency Increasing? This is difficult to establish with a high degree
of statistical confidence; Incompleteness is an important issue
One Good SimulationOne Good Simulation
Using real fluid dynamics Using real fluid dynamics predicted effect is relatively predicted effect is relatively small in the average but the tails are important!small in the average but the tails are important!
DifficultiesDifficulties
Tropical cyclone wind-speed monitoring has Tropical cyclone wind-speed monitoring has changed dramatically over the last few changed dramatically over the last few decades leading to difficulties in determining decades leading to difficulties in determining accurate trends. accurate trends.
There is an observed multi-decadal There is an observed multi-decadal variability of tropical cyclones in some variability of tropical cyclones in some regions whose causes, whether natural, regions whose causes, whether natural, anthropogenic or a combination, are anthropogenic or a combination, are currently being debated. This variability currently being debated. This variability makes detecting any long-term trends in makes detecting any long-term trends in tropical cyclone activity difficult. . tropical cyclone activity difficult. .
Total Power AttributesTotal Power Attributes
Central pressure; central wind speedCentral pressure; central wind speed Total hurricane wind radiusTotal hurricane wind radius Total moisture contentTotal moisture content We do not have good measurements We do not have good measurements
on the latter two except for the last on the latter two except for the last 15 years or so15 years or so