Thursday, December 29, 2016

The 360-Degree Rainbow - By Dr. Jeff Masters

Figure 2. The most intense world tropical cyclones at landfall, using the advisories taken from the National Hurricane Center in the Atlantic and Eastern Pacific, and the Joint Typhoon Warning Center (JTWC) for the rest of the world's oceans. Click to Enlarge.
Tropical cyclones—which include all hurricanes, typhoons, tropical storms and tropical depressions—are expected to change in intensity, frequency, location, and seasonality as a result of climate change.  Many of the tropical cyclones of 2016 exhibited the type of behavior we expect to see more of due to global warming.  Here, then, is a “top ten” list of 2016 tropical cyclone events of the type we should expect to see more of due to global warming.

Examples of the strongest storms getting stronger
Tropical cyclones are heat engines which extract heat energy from the oceans and convert it to the kinetic energy of the storms' winds.  Thus, the strongest tropical cyclones are expected to get stronger in a world with warmer oceans.  It was not a surprise that in 2016—a year with the warmest ocean temperatures on record, globally—we saw the strongest storms ever observed in the two of the six ocean basins that tropical cyclones commonly occur in.  If we include the Northern Hemisphere’s strongest tropical cyclone on record—Hurricane Patrica of October 2015—records have been set in three of the six ocean basins over the past two years.  The two all-time record storms in 2016 were Tropical Cyclone Winston in the South Pacific (180 mph winds, tied for strongest Southern Hemisphere storm on record) and Tropical Cyclone Fantala in the South Indian Ocean (175 mph winds.)  This year also saw seven Category 5 storms, which was the fifth greatest on record (since 1990.) 

Two of the Top Five Landfalling Tropical Cyclones Occurred in 2016
In addition, 2016 also saw two of the top five strongest landfalling tropical cyclones ever recorded—Super Typhoon Meranti with 190 mph winds on the Philippines’ Itbayat Island (tied for Earth’s strongest landfall on record), and Tropical Cyclone Winston with 180 mph winds at landfall in Fiji (the 5th strongest tropical cyclone at landfall in recorded history.)  As we blogged about in August, landfalling typhoons have become more intense since late 1970s, with the peak winds of typhoons striking the region increasing by 12 - 15% since 1977.  “The projected ocean surface warming pattern under increasing greenhouse gas forcing suggests that typhoons striking eastern mainland China, Taiwan, Korea, and Japan will intensify further,” wrote the authors of the study we blogged about.  “Given disproportionate damages by intense typhoons, this represents a heightened threat to people and properties in the region.”

Read more at The 360-Degree Rainbow

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