Better observations, analyses detecting short-lived tropical systems

NOAA: A NOAA-led team of scientists has found that the apparent increase in the number of tropical storms and hurricanes since the late 19th and early 20th centuries is likely attributable to improvements in observational tools and analysis techniques that better detect short-lived storms.

The new study, reported in the online edition of the American Meteorological Society’s peer-reviewed Journal of Climate, shows that short-lived tropical storms and hurricanes, defined as lasting two days or less, have increased from less than one per year to about five per year from 1878 to 2008.

“The recent jump in the number of short-lived systems is likely a consequence of improvements in observational tools and analysis techniques,” said Chris Landsea, science and operations officer at NOAA’s National Hurricane Center in Miami, and lead author on the study. “The team is not aware of any natural variability or greenhouse warming-induced climate change that would affect the short-lived tropical storms exclusively.”

Several storms in the last two seasons, including 2007’s Andrea, Chantal, Jerry and Melissa and 2008’s Arthur and Nana, would likely not have been considered tropical storms had it not been for technology such as satellite observations from NASA’s Quick Scatterometer (QuikSCAT), the European ASCAT (Advanced SCATterometer) and NOAA’s Advanced Microwave Sounding Unit (AMSU), as well as analysis techniques such as the Florida State University’s Cyclone Phase Space…

Short-lived Tropical Storm Chantal forms 210 miles south of Halifax, Nova Scotia on July 31, 2007. Image by NOAA