ISSN 0111-1736 Meteorological Society Of New Zealand (Inc.) NEWSLETTER 110 DECEMBER 2007 Meteorological Society of New Zealand Newsletter - September 2007 - Page 2 Meteorological Society Of New Zealand (Inc.) NEWSLETTER 111 DECEMBER 2007 PO Box 6523, Marion Square, Wellington 6141, New Zealand Please forward contributions to Bob McDavitt, C/- PO Box 68429, Newton, Auckland or [email protected] CONTENTS Page President’s Comments 3 Branch reports 4 Kidson Medal Presentation 5 Rope cloud (by Cliff Revell) 6-8 AGM minutes 9-14 Spring review (NIWA) 14-17 Notable recent weather 18-28 Christchurch weather (Ben) 29 Meteorology in the Press 30-58 Photo competition 59 Weather Crossword 60 Your Committee President Mike Revell [email protected] Immediate Past President Kim Dirks [email protected] Auckland VP Sally Garrett [email protected] Wellington VP Jim Renwick [email protected] Christchurch VP Michael Titov [email protected] Dunedin VP Deborah Hills Secretary Simon Kjellberg [email protected] Treasurer Cliff Revell [email protected] Circulation Manager Rowena Moss [email protected] Journal Editor Brian Giles [email protected] Newsletter Editor Bob McDavitt [email protected] Wed Editor Peter Knudsen [email protected] Hydrological Society Liaison Charles Pearson [email protected] General Committee Stacey Dravitzki [email protected] Katrina Richards [email protected] Sam Dean [email protected] Gareth Renowden Jim Salinger 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 - September 2007 - Page 3 Presidential Greetings After a little arm twisting Richard Turner finally convinced me I should take a turn as President of the Met. Society – thanks Richard. If any of you should notice some similarity with my name and that of the treasurer it is not a coincidence – Cliff is my father. When we both worked at the MetService (actually shared an office for a year!) I needed special per- mission due to the public service laws that existed then. I presume we don’t to both be Met Society committee members. I will be relying on the existing committee to remind me what my duties are – please feel free to let me know. I have no particular agendas to push - apart from wanting to see more of our travel done by cycle and public transport, a greater proportion of our energy supply coming from wind and solar power, a better working relationship between NIWA and MetService and more young people joining the Met Society. On this last point I would be happy for members to send in suggestions to make being a member of the society more attractive for younger people. A few members of the society are making their way to Melbourne for the com- bined Metsoc/Amos conference at the end of January - I hope they have a pro- ductive meeting. I hope you all manage to dodge the ex-tropical cyclones this season. Mike Revell Dr Michael Revell Meteorological Society of New Zealand Newsletter - September 2007 - Page 4 REGIONAL REPORTS Auckland and Wellington Met Society members were invited to a NIWA seminar held in Auckland on 11 Oc- tober and in Wellington on 12 October, featuring presentations from visiting meteorologists >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<< Dr. Marina Baldi presented an investigation into temperature and rainfall sea- sonal anomalies in the Mediterranean and their connection to the large scale features on the Euro-Atlantic. Dr Baldi was on leave from Institute of Biome- teorology (IBIMET – CNR), Rome, Italy. The climate of the Mediterranean is governed by both mid- latitude and tropi- cal dynamics; summers are hot and dry, autumns and winters are wet. In the cold season the westerly flow is relatively strong, and important modes are: the North Atlantic Oscillation (NAO), the Eastern Atlantic pattern (EA), and the Eastern Atlantic/Western Russia pattern. In the warm season, the Azores high dominates, sometimes strengthened by the West African Monsoon, and the large scale flow is generally weak, with breezes driven by local thermal gra- dients, with, towards the end of the season, local extreme precipitation epi- sodes. This is the time of the year that the East Mediterranean is under a ridge connected to the Asian monsoon through Rossby waves. Dr. Baldi looked at the role of the Atlantic jet and of the African jet. The Atlantic jet is generated by the thermal contrast between the cold air over the Polar Ocean and the relatively warm air over the Atlantic ocean and crosses this ocean with a north-easterly tilt. The African jet, generated by the thermal con- trast between the African warm air and the Euro-Asian relatively cold air, spans from the west coast of North Africa to the Indian ocean. In the Mediterranean, summers were hot in the 1950s, 1980s, and 1990, and cool from mid 1960s to mid 1970s; cold seasons were very dry in the 1980s and early 1990s, with an almost monotonic decrease of the rainfall since the 1960s. >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>> Planetary waves and climate and other flows by Dr Giovanni Dalu on leave form Institute of Biometeorology (IBIMET CNR), Rome, Italy Planetary waves have a wavelength of thousands of km. They can be stationary or propagate to east or to the west. They are excited by topographic fea- tures, SSTs, and by changes of snow coverage. There are important since they act as a wave guide for the perturbations. We are studying the propagation of these perturbations and their transition from the tropics into the mid- latitude, as well as mesoscale flows induced by landscape variability. Land- scape variability decreases the temperature in the surface layer, and gener- ates regions of upward vertical motion and a sizable amount of available po- tential energy, and can make the environment of the lower troposphere more fa- vorable to cloud formation. This process is enhanced by light ambient wind through the generation of trapped propagating waves. Meteorological Society of New Zealand Newsletter - September 2007 - Page 5 Dr. Xiaogu Zheng (NIWA) Awarded the 2007 Kidson Medal of the Meteorological Society of New Zealand The Meteorological Society of New Zealand has chosen to award its 2007 Kidson Medal to Dr. Xiaogu Zheng of the National Institute of Water and Atmospheric Research. The medal was presented at the Royal Society of New Zealand’s Awards Dinner held in Dunedin on November 21 st . The medal was awarded for Dr. Zheng’s scientific paper “A study of predictable patterns for seasonal forecasting of New Zealand rainfall” published in the Journal of Climate in 2006. The panel considering the nominations for this year’s Kidson medal considered this work to be outstanding in regards to the advancement in science that this work provides. One of the judges commented that “in terms of seriously advancing knowledge and capability on climate fore- casting, the paper of Dr Zheng will soon be regarded as a land- mark paper, not only for its relevance to New Zealand needs but for most regions in the Southern Hemisphere. It pro- vides remarkable mathematical rigour to the complex world of integrating different components of the climate system.” Dr. and Mrs. Xiaogu Zheng at the presentation ceremony as part of the AGM and International Polar Year seminar held at NIWA in Wellington last November. The Kidson Medal award is named in honour of Dr Edward Kidson, Director of the New Zealand Meteorological Service from 1927 to 1939. Kidson is credited as the first to place New Zealand meteorology on the sound scientific basis it currently enjoys. His scientific work in meteorology covered a wide field and he had an international reputation for his papers on Southern Hemisphere at- mospheric circulation. His papers on New Zealand's climate remained standard works for many years. The Edward Kidson medal is awarded to the author of an outstanding paper published in a refereed scientific journal during the pre- ceding three years. Kim Dirks President of the Meteorological Society of New Zealand, 2007 >>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< Auditor: Our thanks to Alaric Tomlinson who has been able to act as Met Soci- ety auditor over the past seven years in his retirement. We are now looking for a new auditor: someone willing to look over our accounts once a year, in July, and acknowledge that they are a true and complete record of proceedings. If you or someone you know is willing to help the Met Society in this way please let us know with an email to our secretary, [email protected]. >>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<< Meteorological Society of New Zealand Newsletter - September 2007 - Page 6 'Rope' cloud with a 'Southerly buster' Cliff Revell Satellite pictures on the afternoon of the 21st Octo- ber 2007 showed a well- defined 'rope' cloud, a long narrow line of cumulus, marking the leading edge of a frontal cloudband over the Southern Ocean. (Fig.1) This feature retained its iden- tity over the next 24 to 36 hours and on the morning of the 22nd extended southeast- ward from about Cape Turna- gain, having moved at an av- erage speed of 40kt. Fig.1 Visible picture from satellite MTSAT at 1400NZST 21 October 2007 . The cloud band as a whole had become distorted by the landmass of New Zealand into a typical gull-wing shape. (Fig.2). Fig. 2 Visible picture from satellite MTSAT at 0900 NZST 22 October 2007. By mid-afternoon the rope cloud had advanced to a po- sition north of Gisborne and was weakening while becoming separated from the main cloud band, which itself was disintegrating in the New Zealand section (Fig.3).