Report on the Fifth International Workshop on Tropical Cyclones

by Frank Marks (NOAA/AOML/HRD)

IWTC-5 was held in Cairns, Australia from 2-12 December 2002. The meeting was the fifth WMO sponsored International Workshop on Tropical Cyclones held every four years (the next one will be in Costa Rica in 2006). The workshop brings researchers and forecasters together from around the world to discuss new research concepts and forecast practices in a single location. The meeting was organized around five topics and a keynote topic chosen by the chairman of the workshop (Russ Elsberry for IWTC-V). The topics are listed below:


Each topic contained four to five subtopics with rapporteurs giving a summary report each morning session on the activity in that topic area over the last four years. I prepared a rapporteurs report for subtopic 1.1 Observations and Field Programs (see attached Powerpoint file), where I summarized the recent work done with Doppler radars in tropical cyclones (an abbreviated version of my talk from the Atlas Symposium and subsequent book chapter). Shuyi Chen gave the summary for topic 1.5 on advances in numerical modeling of tropical cyclones using examples from storms we have sampled with the aircraft (Bonnie, Floyd). Each subtopic rapporteur working with a committee also presented recommendations to the WMO, the forecast, and research community for consideration (I have a book containing the rapporteur reports). After lunch each day we would break up into 7-8 discussion groups, pairing researchers and forecasters, to discuss the morning rapporteur reports and the recommendations. The task of the discussion groups was to fill in any omissions in the rapporteur’s reports, and to review all of the recommendations, prioritize them, and draft a report to the recommendation committee. These recommendations were the primary purpose of the workshop. After the discussion group meetings there was special focus sessions for each topic in the late afternoon (see list below).

Special Focus Topic 1: Coupled Boundary Layer Air-Sea Transfer (CBLAST)
Special Focus Topic 2: World Weather Research Program on Tropical Cyclone Landfall
Special Focus Topic 3: U. S. Weather Research Project Hurricane Landfall (2004) collaborations
Special Focus Topic 4: Global climate change and tropical cyclones–Basis for an updated statement
Special Focus Topic 5: Australian Tropical Cyclone Coastal Impacts Program Planning

Eric Uhlhorn participated in special focus topic 1 on CBLAST, and I participated in the special focus topic 3 on the HL2004 field program plans. Eric reviewed his recent work with the SFMR and flight level data. I described the issues brought up at the CAMEX meeting in November and gave a short overview of the data sets we collected in HL2001 with CAMEX-4. Russ Elsberry hoped we could announce that CAMEX-5 would join us in 2004, but we are still working on that with NASA. Jim Abraham ( from the Canadian Hurricane Centre in Halifax expressed an interest in adding an extra-tropical transition (ET) component to HL2004, including a Canadian interest in the ocean observations off Nova Scotia. He will hold and ET meeting in late 2003 to get their plans together. They will coordinate with HRD. Nick Shay also gave a summary of the flights in Isidore and Lili in 2002 on the next to the last day.

We also held an impromptu research discussion one night to discuss scientific questions related to intensity and intensity change that could be addressed in HL2004, whether NASA joined us or not. We discussed the CBLAST objectives and what could be added to test John Persing’s (CSU) hypothesis that significant enthalpy (high potential temperature) from the base of the eye could be injected into the eyewall providing a new energy source for the storm. John wants to come down to HRD to talk with Joe Cione, Eric Uhlhorn, and Mike Black about the Bret and Mitch data. In particular, the Bret dropsondes on 21 August when the storm was deepening rapidly may provide a good data set to verify his idea. He was particularly interested in the dropsondes across the eyewall and those done in the eye while the aircraft circled along the eyewall edge. He is also interested in the SST under the eyewall from the AXBTs. I told him he should interact with the Bret group to insure no overlap of efforts. I think this is a good possibility for collaboration.

I also talked with Jeff Kepert ( about his pending visit to HRD in April (he will come for 3 weeks). Jeff is pursing his research interest in the ABL changes at landfall using the Doppler radar and dropsonde data sets we have. He will be contacting some HRD folks (and Nick Shay) about the GPS dropsondes he wants to look at in Hurricanes Bonnie, Floyd, Mitch, Bret, Erin, Isidore, and Lili. Jeff is examining the tangential and radial wind structure in the ABL looking for asymmetries in the structure caused by storm motion and landfall. He gave an excellent overview of this work in his talk in Topic 2 at the workshop (an extension of his San Diego talk). He is also interested in looking at the VAD data sets we have from landfall cases.

I also talked with Russell Morison from the University of New South Wales ( about CBLAST and boundary layer observations. Russell works with Lance Leslie at University of Oklahoma and Mike Banner ( at University of New South Wales (CBLAST PI) on modeling and data assimilation. He is interested in visiting HRD in February. Roger Smith (roger@ from the University of Munich and Johnny Chan ( from the City University of Hong Kong asked me about having some folks from their universities visit HRD over the summer. Roger expressed interest in coming himself this summer. I suggested they both send me a letter listing what they might be interested in doing which I would direct to the appropriate HRD person to contact. I also spoke to Chun Chieh Wu about possible HRD participation in the Taiwan surveillance tests this summer. Chun Chieh expressed an interest in Sim visiting for a few weeks to a month. I told him it was up to Sim. Therefore, he will be contacting Sim in the near future to see how long he can visit.

I was also involved in an organizational meeting for the World Weather Research Program (WWRP) Hurricane Landfall effort. At the meeting of the WMO Tropical Meteorology Research Program (TMRP, chaired by Lianshou Chen of China) in November they endorsed the WWRP proposal for a tropical cyclone landfall program presented by Gary Foley (BOM, Perth, The TMRP felt that the objectives were too narrow (focus on improved surface wind and rainfall forecasts) and recommended the formation of a Science Steering Committee for the program to define a more complete list of objectives. HRD was invited to participate. They are looking for both a person from HRD and a surface wind expert. Therefore, I recommended Mark Powell. Mark should expect an invitation letter.