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Meteorological Society of New Zealand Newsletter - March 2011 - Page 1 ISSN 0111-1736 Meteorological Society Of New Zealand (Inc.) NEWSLETTER 124 MARCH 2011 Meteorological Society of New Zealand Newsletter - March 2011 - Page 2 Meteorological Society Of New Zealand (Inc.) NEWSLETTER 124 MARCH 2011 PO Box 6523, Marion Square, Wellington 6141, New Zealand Please forward contributions to Bob McDavitt, [email protected] CONTENTS Page President’s Report 3 Conference 3-4 Cyclone Wilma 4-5 Photo Competition 6-7 Summer 2010 2011 (NIWA) 7-8 Summer – in the media 9-41 Your new Committee President Andrew Tait [email protected] Immediate Past President Kim Dirks [email protected] Auckland VP Jennifer Salmond [email protected] Wellington VP James Renwick [email protected] Christchurch VP Colin Simpson Dunedin VP vacant Secretary Sam Dean [email protected] Treasurer Alan Porteous [email protected] Circulation Manager Sylvia Nichol [email protected] Journal Editor Brian Giles [email protected] Newsletter Editor Bob McDavitt [email protected] Wed Editor Peter Knudsen Hydrological Soc Liaison Charles Pearson [email protected] General Committee Jim Salinger [email protected] Mike Revell [email protected] Katrina Richards [email protected] Gareth Renowden [email protected] Duncan Ackerley Views and endorsements expressed in this newsletter are those of the contributors and advertisers, and not necessarily those of the Meteorological Society of New Zealand. The mention of specific companies or products does not imply that they are endorsed or recommended by the Society. Meteorological Society of New Zealand Newsletter - March 2011 - Page 3 President's Report A month or so after I started work at NIWA in May 2000, James Renwick (bless him) came into my office and said to me "Hey man, you should join the Met Soc! We're a great bunch and we have really stimulating meetings and you should be on the committee and, by the way, we need a circulation manager so can you do that too?" I was so fresh faced and eager that I agreed to everything - I mean who could refuse that kind of offer? Five years later I passed the circulation manager mantle onto Rowena Moss (who has since passed it on further to Sylvia Nichol) and I quietly excused myself from the committee and then got on with other things. Step forward another five years or so and I'm back, surprisingly via not too different a mechanism that was used on me the first time (you would have thought I might be a little wiser with age?) except this time it was Mike Revell (bless him too) doing the cajoling and the job on offer was the presidency. I said yes, and so here I am. But who am I? I'm a principal scientist at the National Climate Centre (NCC) at NIWA, Wellington. I manage the day-to-day operations of the NCC, assisting the Chief Scientist – Climate on science plan- ning, providing decision support as a member of the NCC management team, identifying new research opportunities, overseeing website uploads and upgrades, coordinating speaking en- gagements, and acting as a point-of-contact for the Centre (both internal to NIWA and exter- nally). I also try to fit in some research. I specialise in climate variability and change impacts and adaptation research, spatial interpolation methods of climate data and the application of GIS and remote sensing tools for climate analysis. I'm also one of the lead authors on the Aus- tralasia chapter of the IPCC Working Group 2 Fifth Assessment Report (AR5). I'm actually very honoured to have been nominated for the presidency of the Meteorological Society of New Zealand and to have had this nomination carried at the recent AGM. I hope to continue the very fine tradition of recent presidents and to work well with the very dedicated and capable committee. I will also do my very best to represent the Met Society well as a spokesman whenever necessary, both nationally and internationally. Sincerely, Andrew Tait 2011 President, Meteorological Society of New Zealand COMBINED AMOS/MET SOC Conference * Te Papa Feb 2011-04-16 Mike Revell reported this conference was the best he had ever attended. The excellent Wel- lington weather over the three days was acknowledged (as a contender for extreme event). 100 attendees from Australia helped raise the standard of the conference greatly. He said that he had received only positive feedback. Mike noted the excellent work that Janet Symes did in making sure the conference ran smoothly. There should be a final profit from the con- ference of about $7000. It had been decided that due to the equal number of New Zealand and Australian attendees that this would be split evenly. Taking into account Met Soc support for student attendees, the net profit for the Metsoc would be about $1500 Meteorological Society of New Zealand Newsletter - March 2011 - Page 4 Press Release: NIWA SCIENTIST AWARDED MET SOCIETY KIDSON MEDAL Climate Scientist Dr. Andrew (Drew) Lorrey of the National Institute of Water and Atmos- pheric Research has been awarded the 2010 Edward Kidson Medal by the Meteorological Society at the recent Extreme Weather 2011 meteorological conference in Wellington. The award was for Lorrey’s “Regional climate regime classification as a qualitative tool for interpreting multi-proxy paleoclimate data spatial patterns: A New Zealand perspective” published in 2006 in the Journal Paleo- geography, Paleoclimatology, Paleoecology. The judging panel considered this work to be both timely and outstanding in its quality. One of the judge’s comments on this paper was that it “recognised that precipitation, not temperature, is the key for understanding past changes in circulation regimes. The key insight is that… weather over New Zealand can be usefully condensed into just three circulation types: zonal, trough and blocking, operating over four seasonal time slices.” The Kidson Medal award is named in honour of Dr Edward Kidson, Director of the New Zea- land Meteorological Service from 1927 to 1939. His scientific work in meteorology covered a wide field and he had an international reputation for his papers on Southern Hemisphere at- mospheric circulation. The Edward Kidson medal is awarded by the New Zealand Meteoro- logical Society (metsoc.rsnz.org) to the author of an outstanding paper published in a refe- reed scientific journal during the preceding three years. Next Conference – Nelson Mid-November 2011. More details later. A note on Tropical Cyclone Wilma (Cliff Revell) It has been claimed that Tropical Cyclone Wilma (January 2011) was "the first tropical cy- clone to reach New Zealand", a statement which has appeared in Wikipedia. This note at- tempts to place Wilma in historical perspective. First the question of when a tropical cyclone (TC) ceases to be a TC. Studies {see Sinclair (2004) and references therein} have shown that the transformation of TCs as they move into middle latitudes, or extratropical transition (ET), is largely determined by the nature of the mid-latitude circulation into which the TC moves. As a result there can be various outcomes (Revell 1995). The onset of ET can be defined objectively. Sinclair (2004) developed a crite- rion for onset based on thermal asymmetry. This would require diagnostic analysis to apply in the case of Wilma. However, onset can also be assessed from the appearance of ascent asymmetry in satellite pictures as inferred vertical motion becomes progressively concen- trated in the forward or southeastern sector of the system. Sinclair (2004) quoted some ex- amples in which it was found that this occurred some 6 to 8 hours before the thermal asym- metry criterion was met. In the case of Wilma it can be deduced that ET had begun by the time the cyclone reached latitude 30 South but the low-level vortex, slowly spinning down, was re- tained. As Wilma approached northern New Zealand, the weakening storm began to interact with a jet stream to the south. Steep, sloping ascent of moist tropical air into the equator- ward entrance region of the jet led to torrential rain over many northern and eastern parts of the North Island. Continuing southeast-ward, Wilma moved into the region near 40 South just to the east of an approaching upper trough. This created a favourable upper-divergence environment for sur- face development and Wilma began to re-intensify. Within 6 to 12 hours it became a vigorous mid-latitude (baroclinic) storm near the Chatham Islands at which time it lay between the poleward exit region of an upstream jet and the equator-ward entrance region of a down- stream jet. The appearance of this double-jet structure coincided with the maximum redevel- opment. The behaviour of TC Wilma had some similarity to that of Gisele (April 1968) but it was much less severe. Historical storms During the last 40 years, over 50 tropical cyclones of various intensities have passed to the south of 30 South between longitudes 160 East and 175 West. Only a small fraction of these were severe fast-moving storms with almost straight-line tracks. These are listed in the ap- pendix. All of these storms, along with TC Wilma, were undergoing ET when they reached New Zealand waters. Several reintensified around or south of latitude 35 South. Among the most notable were Alison and Bernie. Both retained winds in the storm force range (48-63kt, 89- 117km/h) well into middle latitudes. Alison (Tomlinson, 1975) caused severe erosion and landslides as well as damaging winds, particularly in Nelson Marlborough and Hawkes Bay. Bernie (Revell and Ward, 1982), passing to the east of the country, was associated with possibly the most severe southeasterly windstorm over the North Island since the storms of 1936 ( Littlejohn,1982).