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Compendium on Tropical Meteorology for Aviation Purposes

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Compendium on Tropical Meteorology for Aviation Purposes Compendium on Tropical Meteorology for Aviation Purposes 2020 edition WEATHER CLIMATE WATER CLIMATE WEATHER WMO-No. 930 Compendium on Tropical Meteorology for Aviation Purposes 2020 edition WMO-No. 930 EDITORIAL NOTE METEOTERM, the WMO terminology database, may be consulted at https://public.wmo.int/en/ meteoterm. Readers who copy hyperlinks by selecting them in the text should be aware that additional spaces may appear immediately following http://, https://, ftp://, mailto:, and after slashes (/), dashes (-), periods (.) and unbroken sequences of characters (letters and numbers). These spaces should be removed from the pasted URL. The correct URL is displayed when hovering over the link or when clicking on the link and then copying it from the browser. WMO-No. 930 © World Meteorological Organization, 2020 The right of publication in print, electronic and any other form and in any language is reserved by WMO. Short extracts from WMO publications may be reproduced without authorization, provided that the complete source is clearly indicated. Editorial correspondence and requests to publish, reproduce or translate this publication in part or in whole should be addressed to: Chair, Publications Board World Meteorological Organization (WMO) 7 bis, avenue de la Paix Tel.: +41 (0) 22 730 84 03 P.O. Box 2300 Fax: +41 (0) 22 730 81 17 CH-1211 Geneva 2, Switzerland Email: [email protected] ISBN 978-92-63-10930-9 NOTE The designations employed in WMO publications and the presentation of material in this publication do not imply the expression of any opinion whatsoever on the part of WMO concerning the legal status of any country, territory, city or area, or of its authorities, or concerning the delimitation of its frontiers or boundaries. The mention of specific companies or products does not imply that they are endorsed or recommended by WMO in preference to others of a similar nature which are not mentioned or advertised. PUBLICATION REVISION TRACK RECORD Part/ Date chapter/ Purpose of amendment Proposed by Approved by section CONTENTS Page FOREWORD . vii INTRODUCTION . viii CHAPTER 1 . DEFINITIONS AND UNITS . 1 1.1 Definition of the tropics. 1 1.2 Units used in this Compendium ............................................... 1 CHAPTER 2 . SEASONAL AND LARGE-SCALE INFLUENCES . 2 2.1 General circulation of the atmosphere .......................................... 2 2.2 Major wind and pressure zones ............................................... 4 2.3 Trade winds ................................................................ 5 2.4 Inter-tropical convergence zone. 7 2.5 Monsoons ................................................................. 9 2.6 El Niño/Southern Oscillation .................................................. 18 2.7 Walker circulation ........................................................... 18 2.8 Observing large-scale circulation from geostationary satellites ..................... 20 CHAPTER 3 . SYNOPTIC-SCALE PHENOMENA AND TROPICAL CYCLONES . 29 3.1 Synoptic-scale systems ....................................................... 29 3.2 Synoptic-scale disturbances .................................................. 29 3.3 Tropical cyclones ............................................................ 33 3.3.1 Definition ........................................................... 33 3.3.2 Classification ........................................................ 33 3.3.3 Cyclogenesis ........................................................ 33 3.3.4 Structure ........................................................... 34 3.3.5 Tracks .............................................................. 34 3.3.6 Decay. 35 3.3.7 Climatology ......................................................... 36 3.3.8 Observations and modelling. 37 3.3.9 Observing network .................................................. 37 3.3.10 Related hazards ...................................................... 38 3.3.11 Tropical cyclone advisory centres (TCACs) ............................... 38 CHAPTER 4 . MESOSCALE PHENOMENA . 40 4.1 Importance of mesoscale phenomena .......................................... 40 4.2 Land and sea breezes ........................................................ 40 4.3 Orographic effects .......................................................... 42 4.4 Thunderstorms ............................................................. 42 4.5 Severe storms .............................................................. 44 4.6 Thunderstorm development and prediction ..................................... 44 4.7 Thunderstorm-related phenomena ............................................ 46 4.8 Lightning .................................................................. 50 4.9 Sandstorms and dust storms .................................................. 51 4.10 Dust devils ................................................................. 52 4.11 Low-level wind shear ........................................................ 52 4.12 Turbulence ................................................................. 52 4.13 Low-level jets ............................................................... 54 4.14 Mountain waves ............................................................ 54 vi COMPENDIUM ON TROPICAL METEOROLOGY FOR AVIATION PURPOSES Page CHAPTER 5 . VOLCANIC ACTIVITY . 56 5.1 Volcanically active regions of the world ......................................... 56 5.2 Aircraft encounters with volcanic ash ........................................... 57 5.3 International Airways Volcano Watch (IAVW) ................................... 59 5.4 Volcanic ash as an aviation hazard ............................................. 59 5.5 Nature of the damage to aircraft ............................................... 60 5.6 Monitoring volcanic eruptions and volcanic ash clouds ........................... 61 5.7 Advisory and warning systems ................................................ 62 5.8 The Australian advisory and warning system (example) ........................... 64 CHAPTER 6 . GENERAL HINTS FOR WEATHER-WISE FLYING IN THE TROPICS . 68 6.1 Introduction ............................................................... 68 6.2 Regulatory and guidance material for the provision of meteorological services for international air navigation ................................................ 68 6.3 Understanding basic tropical meteorology relevant to aviation .................... 68 6.4 Avoiding hazards while flying ................................................. 69 6.5 Aircraft reports ............................................................. 70 6.6 Meteorological code forms ................................................... 70 6.7 Concluding remarks ......................................................... 70 REFERENCES . 71 FOREWORD The Compendium on Tropical Meteorology for Aviation Purposes was first published by WMO in 2003 in response to requests raised at the ninth (1990) and eleventh (1999) sessions of the WMO Commission for Aeronautical Meteorology (CAeM). CAeM noted that pilots based in temperate latitudes were mainly trained in temperate latitude meteorology and that a need existed to train pilots in tropical meteorology. Based on manuscripts developed by CAeM experts in the 1990s, the first edition of the Compendium was prepared by the WMO Secretariat with the kind assistance of Prof. T.N. Krishnamurti of the Florida State University in Tallahassee, Florida, United States of America, and the then President of CAeM, Dr N. Gordon of New Zealand. Subsequent to the sixteenth session of CAeM (Exeter, 2018), and recognizing the continuing utility of and need for a compendium on tropical meteorology for aviation purposes, in 2019, the CAeM Management Group agreed that a review and update of the Compendium should be undertaken. Under the direction of the President of CAeM, Mr I. Lisk (United Kingdom of Great Britain and Northern Ireland), a CAeM Expert Team on Education, Training and Competency and various leading subject matter experts were tasked with assisting the WMO Secretariat in undertaking this review and update. This second edition of the Compendium is the culmination of that work. It builds on the first edition and makes it current with respect to tropical meteorology of relevance to the aviation sector and the risks posed to aviation operations caused by weather and other phenomena in the tropics, risks which may increase due to climate change. I wish to express my sincere thanks to all those who assisted WMO in the publication of this second edition. In particular, I wish to thank Mr L. Alves (Guyana), Ms K-A. Caesar (British Caribbean Territories), Ms G. Khambule (South Africa), Ms A. Henderson (Australia), Ms Y. Igarashi (Japan), Dr J. Denman (Australia), Mr A. Muscat (United Kingdom) and Mr D. Bensimon (Canada) for their excellent contributions. It is my hope that this publication will prove useful to the aviation users worldwide for whom it is primarily intended and that it will serve as a valuable reference for observers and forecasters within and beyond the aeronautical meteorology community. (Prof. Petteri Taalas) Secretary-General INTRODUCTION Purpose of the Compendium The purpose of this Compendium is to provide information on tropical meteorology that is of relevance to the aviation sector and information on the hazards that weather and other phenomena in the tropics may pose to aviation operations. Structure of the Compendium This Compendium describes some fundamental aspects of meteorological phenomena
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