Tropical cyclones are one of nature’s most destructive manifestations. Known as hurricanes in the Atlantic and typhoons in the Pacific, they operate as a heat engine, gaining energy from the warm ocean and converting it to extreme wind speeds. Tropical cyclones can grow to have radius upwards of 500 km and travel thousands of km gaining strength. When these storms make landfall their devastation is counted in both the loss of
life and the devastation to property and infrastructure. Hurricane Sandy’s landfall alone killed over 70 people, while the financial burden is estimated will be as much as $50 billion, $20 billion coming from damages and $10 billion to $30 billion due to loss of business.
Understanding the dynamics of tropical cyclones is one of scientists’ most pressing challenges. Assembling intricate information about the mechanisms which drive them is a critical component of accurately predict their movement and intensity. By improving our forecasts we can be primed to deal with future landfalling storms.
Understanding the processes that govern the transfer of energy between the ocean and atmosphere during tropical storms is the essence of my research at RSMAS. My working group is a component of the ITOP (Impact of Typhoons on the Ocean in the Pacific) campaign, which is devoted to understanding the ocean’s response to typhoons in the Western Pacific. The research is a multinational collaboration employing both field observations and models from many research institutions.
My contribution to the campaign started during the 2010 Pacific typhoon season when a team of A.M.P. students and research staff, working with Drs. Hans Graber and Will Drennan, helped deploy two mooring pairs in the Philippine Sea. The moorings were anchored ~740 miles east of Southern Taiwan. Each pair consisted of an Air-Sea Interaction Spar (ASIS) tethered to a moored Extreme Air-Sea Interaction (EASI) buoy. The platforms were equipped to make multiple atmospheric and oceanographic measurements.
Environmental conditions were monitored and recorded for over three months, a period which included the passage of three typhoons and one tropical storm. Sustained wind speeds over 26m/s and significant wave heights exceeding 10m were experienced.
Looking at the data we can see how dynamic the environment becomes with the passage of these storms. Along with increased wind speeds and wave height, we witnessed ocean and air temperatures changing, transformation of the ocean mixed layer structure, increased sea spray, pressure dropping, relative humidity increasing, and changes in the wind and wave direction, amongst other phenomena. With further investigation we’ll also learn how these storms affect aerosol composition, momentum and heat fluxes, and the evolution of the wave field.
Making in situ measurements at sea in such harsh conditions is extremely challenging, very few groups are equipped to do so, making this a very unique and valuable dataset. The potential to use this data to learn about how typhoon conditions affect the marine environment is effectively limitless. I am just one of a group of students and research staff who continue to investigate this data to uncover information about high wind speed boundary layer dynamics.
I was pleased to be recognized for my poster at the AMS conference on air-sea interaction, but I am one of many people who participated in the research. I was just lucky enough to be there to present some of our findings.
Henry Potter is a Ph.D. candidate in Applied Marine Physics at the University of Miami’s Rosenstiel School of Marine & Atmospheric Science.