Tropical Cyclones and Climate Change John Mcbride Research Group Leader: Weather and Environmental Prediction Centre for Australian Weather and Climate Research

Tropical Cyclones and Climate Change John McBride Research Group Leader: Weather and Environmental Prediction Centre for Australian Weather and Climate Research

Co-Chair World Weather Research Programme Expert Team on Climate Change Impacts on Tropical Cyclones.

Centre for Australian Weather and Climate Research: a research partnership between CSIRO and the Bureau of Meteorology Centre for Australian Weather and Climate Research: a research partnership between CSIRO and the Bureau of Meteorology • Statement was issued in December 2006 -13 pages, including references…. Available on WMO website under WWRP Tropical Meteorology Research Program • New statement planned for late 2008, under direction of WWRP Expert Team on Climate Change Impacts on tropical cyclones.

Centre for Australian Weather and Climate Research: a research partnership between CSIRO and the Bureau of Meteorology New Orleans USA after Hurricane Katrina 2005 1300 deaths from a tropical cyclone in the country with the most advanced monitoring, forecasting and warning Before and after satellite images of systems in the world flooding of Irrawaddy river delta, Myanmar, May 2008 Estimated more than 100,000 deaths Centre for Australian Weather and Climate Research: a research partnership between CSIRO and the Bureacu aofu Mesteodrol obgyy Tropical Cyclone Nargis Pacific Island Nations:

Tropical Cyclone Heta destroyed the infrastructure of the Island nation of Niue, January 2004. The building in ruins in the left photo was the Nation’s hospital Other examples: Tropical Cyclone Waka that hit Tonga in December 2001. Five cyclones in one month in Cook Islands, 2005 Centre for Australian Weather and Climate Research: a research partnership between CSIRO and the Bureau of Meteorology Impact on Industry: The tracks of category 4 and 5 tropical cyclones (10 minute sustained winds greater than 45 m/sec) affecting the mining ports of Port Hedland, Karratha and Cape Lambert (red squares) over a ten year period.

Industry estimates put the cost of closure of any one of these ports as being of the order of $3 million Australian per day.

Centre for Australian Weather and Climate Research: a research partnership between CSIRO and the Bureau of Meteorology Hurricane Katrina USA 2005

Typhoon Longwan Taiwan 2005 T.C Glenda Australia 2006

Centre for Australian Weather and Climate Research: a research partnership between CSIRO and the Bureau of Meteorology Centre for Australian Weather and Climate Research: a research partnership between CSIRO and the Bureau of Meteorology Centre for Australian Weather and Climate Research: a research partnership between CSIRO and the Bureau of Meteorology Centre for Australian Weather and Climate Research: a research partnership between CSIRO and the Bureau of Meteorology We know quite a lot about tropical cyclones • Good understanding of their energetics • Have a good knowledge of their relationship with large scale structures of the atmosphere -- Following the work of W.M. Gray:

Centre for Australian Weather and Climate Research: a research partnership between CSIRO and the Bureau of Meteorology Climatologically: Tropical cyclones related to warm sea surface temperature, monsoon trough, upward vertical motion (measured by RH), vorticity at top of boundary layer, and small vertical shear Through the underlying dynamics of the atmosphere (geostrophy, thermal wind) vertical shear is equivalent to horizontal temperature gradients through the middle troposphere

For midlatitude (baroclinic) weather systems the potential energy stored in horizontal temperature gradients is the source of energy for the system. Whereas, a formation of a tropical cyclone requires that the vertical shear (and so horizontal temperature gradients) be small. Thus have two distinct families of synoptic-scale cyclones on earth: Centre for Australian Weather and Climate Research: a research partnership between CSIRO and the Bureau of Meteorology Necessary conditions for Necessary conditions for mid-latitude/baroclinic tropical cyclone cyclone

Wind profile

Potential temperature (constant cold warm density) lines close to horizontal

Centre for Australian Weather and Climate Research: a research partnership between CSIRO and the Bureau of Meteorology IWTC 20076 Statement: Globally the major factor affecting tropical cyclone frequency on an interannual timescale is ENSO

Centre for Australian Weather and Climate Research: a research partnership between CSIRO and the Bureau of Meteorology Examples of ENSO impact: NW Pacific (Chan, 2005) Southern Hemisphere Kuleshov et al 2007

Centre for Australian Weather and Climate Research: a research partnership between CSIRO and the Bureau of Meteorology FOUR IMPEDIMENTS TO MAKING PROJECTIONS OF TROPICAL CYCLONE BEHAVIOUR UNDER CLIMATE CHANGE

1. RESOLUTION:The essential aspects of a tropical cyclone (eye wall, parameters governing intensity) are a smaller scale than can be resolved under climate models ---- and the science of downscaling, nesting of higher resolution models etc is in its infancy 2. Current and future tropical cyclone behaviour depend on ENSO, monsoon trough, vertical shear, upward motion etc…There is still very little agreement between global models on how these large scale phenomena will change 3. Detection and attribution - intensity estimates basically by satellite… still no agreement even on recent trends. Also there are known lareg interdecadal oscillations 4. Theory: Don’t have basic understanding/agreed theories for either genesis or intensity

Centre for Australian Weather and Climate Research: a research partnership between CSIRO and the Bureau of Meteorology Detection and attribution: Comparison of official tracks versus a satellite intensity detection by Kossin et al GRL 2006

Parameter is percentage of category 4-5 (2 standard deviations from series median)

Atlantic West Pacific Best track satellite

Centre for Australian Weather and Climate Research: a research partnership between CSIRO and the Bureau of Meteorology South Indian Ocean South Pacific

Australian National Climate Centre new data set of tracks: Southern Hemisphere 90 - 160 E 130 systems have been removed from official tracks

1. RESOLUTION:The essential aspects of a tropical cyclone (eye wall, parameters governing intensity) are a smaller scale than can be resolved under climate models ---- and the science of downscaling, nesting of higher resolution models etc is in its infancy 2. Current and future tropical cyclone behaviour depend on ENSO, monsoon trough, vertical shear, upward motion etc…There is still very little agreement between global models on how these large scale phenomena will change 3. Detection and attribution - intensity estimates basically by satellite… still no agreement even on recent trends. Also there are known large interdecadal oscillations 4. Theory: Don’t have basic understanding/agreed theories for either genesis or intensity

Centre for Australian Weather and Climate Research: a research partnership between CSIRO and the Bureau of Meteorology FOUR REASONS FOR OPTIMISM There is a lot of good work goiung on in all four areas, with a lot of progress: Tropical cyclone projections forming a vanguard for tornadoes, hail, urban quality etc

1. RESOLUTION:The essential aspects of a tropical cyclone (eye wall, parameters governing intensity) are a smaller scale than can be resolved under climate models ---- and the science of downscaling, nesting of higher resolution models etc is in its infancy 2. Current and future tropical cyclone behaviour depend on ENSO, monsoon trough, vertical shear, upward motion etc…There is still very little agreement between global models on how these large scale phenomena will change 3. Detection and attribution - intensity estimates basically by satellite… still no agreement even on recent trends. Also there are known large interdecadal oscillations 4. Theory: Don’t have basic understanding/agreed theories for either genesis or intensity

Centre for Australian Weather and Climate Research: a research partnership between CSIRO and the Bureau of Meteorology How can the WWRP-WCRP community and the Off-Shore Industry community work together?

Data sets: Industry needs probability distributions of wind, intensity, sea state etc

Centre for Australian Weather and Climate Research: a research partnership between CSIRO and the Bureau of Meteorology Centre for Australian Weather and Climate Research: a research partnership between CSIRO and the Bureau of Meteorology How can the WWRP-WCRP community and the Off-Shore Industry community work together?

Data sets: Industry needs probability distributions of wind, intensity, sea state etc You don’t have these for current climate: --- No agreement on intensity before mid-eighties at earliest. Recent Australian track re-analysis removed 130 systems. No consistent data set yet for rest of Southern Hemisphere, Indian Ocean

Work with us, support us on managing, reconstructing, comparing, archiving, disseminating the data sets.

Other ideas: Look at pilot reconnaissance programs in other basins, beside Atlantic -- at least to baseline satellite intensity estimates

Work with/sponsor( ?) our World Weather Research Programme Expert Team on Climate Change Impacts on Tropical Cyclones.

Other ideas will come hopefully in the next few days. Data sets: Industry needs probability distributions of wind, intensity, sea state etc