Hurricanes Smoking Guns of Climate Change or random

Hurricanes Smoking Guns of Climate Change or random occurrences?

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 n Low pressure centers form over Sahara desert and may get amplified as they cross open ocean n Amplification depends critically on SST and available moisture in the atmosphere n Must also have favorable wind conditions (light winds aloft) and weak wind shear

Hurricane Frequency Increasing? n This is difficult to establish with a high degree of statistical confidence; Incompleteness is an important issue

Counting is always noisy RADAR in the 1950 s

Atlantic Multi-decadal Oscillation (AMO)

Frequency Mimics AMO

One Good Simulation § Using real fluid dynamics predicted effect is relatively small in the average but the tails are important!

Difficulties Tropical cyclone wind-speed monitoring has changed dramatically over the last few decades leading to difficulties in determining accurate trends. n There is an observed multi-decadal variability of tropical cyclones in some regions whose causes, whether natural, anthropogenic or a combination, are currently being debated. This variability makes detecting any long-term trends in tropical cyclone activity difficult. . n

Total Power Attributes n Central pressure; central wind speed n Total hurricane wind radius n Total moisture content n We do not have good measurements on the latter two except for the last 15 years or so

But, this may be a diagnostic

Track Density Analysis