State of the Climate in 2007 For information about WMO, please contact: World Meteorological Organization 7 bis, avenue de la Paix – P.O. Box 2300 – CH 1211 Geneva 2 – Switzerland www.wmo.int Communications and Public Affairs Office Tel.: +41 (0) 22 730 83 14 – Tel.: +41 (0) 22 730 83 15 – Fax: +41 (0) 22 730 80 27 E-mail: [email protected] OF THE CLIMATE INSTATE 2007 WMO-No. 1036 State of the Climate in 2007 D.H. Levinson and J.H. Lawrimore, Editors Associate Editors A. Arguez, H.J. Diamond, F. Fetterer, A. Horvitz and J.M. Levy WMO-No. 1036 © World Meteorological Organization, 2009 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: Chairperson, 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 80 40 CH-1211 Geneva 2, Switzerland E-mail: [email protected] ISBN 978-92-63-11036-7 Cover: After the rain. Illustration by Sabina Khamidova, 14 years old, Uzbekistan This publication was adapted, with permission, from the “State of the Climate in 2007”, published as a supplement to the Bulletin of the American Meteorological Society, Volume 89, Number 7, July 2007, available online at dx.doi.org/10.1175/BAMS-89-7-StateoftheClimate. 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CONTENTS Foreword .................................................................................................................................... vii Abstract ...................................................................................................................................... viii Authors’ affiliations .................................................................................................................. ix 1. Introduction ........................................................................................................................... 1 2. Global climate ........................................................................................................................ 7 A. Overview ........................................................................................................................... 7 B. Global temperature .......................................................................................................... 7 1. Surface temperature .................................................................................................... 7 2. Upper-air temperatures ............................................................................................... 9 C. Hydrologic cycle ............................................................................................................... 12 1. Global precipitation ..................................................................................................... 12 2. Northern hemisphere continental snow cover extent .............................................. 15 3. Global cloudiness ......................................................................................................... 16 D. Trace gases and aerosols ................................................................................................ 18 1. Carbon dioxide ............................................................................................................. 18 2. Methane ........................................................................................................................ 19 3. Carbon monoxide ......................................................................................................... 20 4. Halocarbons .................................................................................................................. 20 5. Nitrous oxide and sulfur hexafluoride ....................................................................... 22 6. The combined influence of long-lived trace gases on the radiative balance of the atmosphere ........................................................................................................ 22 7. Global aerosols ............................................................................................................. 23 E. Global winds ..................................................................................................................... 25 1. Ocean winds ................................................................................................................. 25 2. Continental winds ........................................................................................................ 26 F. Major modes of northern hemisphere variability: the Arctic Oscillation and the Pacific–North American pattern ............................................................................... 27 1. Record PNA pattern during July–September ............................................................ 27 2. The AO flips sign during the 2006–2007 winter ........................................................ 28 3. Global oceans ........................................................................................................................ 31 A. Overview ........................................................................................................................... 31 B. Temperature ...................................................................................................................... 32 1. Sea surface temperatures in 2007 .............................................................................. 32 2. Ocean heat content ...................................................................................................... 34 3. Global ocean heat fluxes ............................................................................................. 35 4. Tropical cyclone heat potential ................................................................................... 37 C. Sea surface salinity .......................................................................................................... 40 D. Circulation ......................................................................................................................... 42 1. Surface current observations ..................................................................................... 42 2. The meridional overturning circulation ..................................................................... 44 iii E. Sea-level variations ........................................................................................................... 46 F. The global ocean carbon cycle ........................................................................................ 47 1. Air–sea carbon dioxide fluxes ...................................................................................... 47 2. Subsurface carbon inventory ...................................................................................... 50 G. Global ocean phytoplankton and productivity .............................................................. 52 4. The tropics ............................................................................................................................. 57 A. Overview ............................................................................................................................ 57 B. ENSO and the tropical Pacific........................................................................................... 57 C. The Madden–Julian oscillation ....................................................................................... 60 D. Tropical cyclones .............................................................................................................. 62 1. Overview ........................................................................................................................ 62 2. Atlantic basin ................................................................................................................. 62 3. Eastern North Pacific basin ......................................................................................... 66 4. Western North Pacific basin ........................................................................................ 68 5. Indian Ocean basins ..................................................................................................... 70 6. South-west Pacific basin ............................................................................................. 72 7. Australian basin ............................................................................................................ 73 E. Intertropical convergence zones ....................................................................................