Annual Report on the Climate System 2016
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Annual Report on the Climate System 2016 March 2017 Japan Meteorological Agency Preface The Japan Meteorological Agency is pleased to publish the Annual Report on the Climate System 2016. The report summarizes 2016 climatic characteristics and climate system conditions worldwide, with coverage of specific events including the effects of the summer 2014 – spring 2016 El Niño event and notable aspects of Japan’s climate in summer 2016. I am confident that the report will contribute to the understanding of recent climatic conditions and enhance awareness of various aspects of the climate system, including the causes of extreme climate events. Teruko Manabe Director, Climate Prediction Division Global Environment and Marine Department Japan Meteorological Agency Contents Preface 1. Explanatory notes ··························································································· 1 1.1 Outline of the Annual Report on the Climate System ······································· 1 1.2 Climate in Japan ···················································································· 1 1.3 Climate around the world ························································ ·············· 2 1.4 Atmospheric circulation ············· ···························································· 3 1.5 Oceanographic conditions ··········· ··············································· ·········· 5 1.6 Snow cover and sea ice ······································································· 5 2. Annual summaries of the 2016 climate system ········································· ··· 6 2.1 Climate in Japan ················ ··········· ···················································· 6 2.2 Climate around the world ···································································· 12 2.3 Extratropical circulation ·············· ····················································· 19 2.4 Tropical circulation and convective activity ··· ················ ··················· ·· ·· 2 4 2.5 Oceanographic conditions ········· ······················· ··················· ··············· 33 2.6 Stratospheric circulation in boreal winter ····················································· 36 2 .7 Summary of the Asian summer monsoon ··················· ··············· ······· ······· ·· 41 2.8 Arctic sea ice conditions ············································································ 45 2.9 Snow cover in the Northern Hemisphere ························································· 47 3. Analysis of specific events ········································································· 49 3.1 T he El Niño event ending boreal spring 2016 and its effects ······················· 49 3.2 Extreme climate conditions in Japan in August 2016 ····································· 68 1. Explanatory notes phenomenon. Average temperatures over Japan are first 1.1 Outline of the Annual Report on the Climate derived based on temperature deviations from the 1971 – System 2000 average of the 15 stations, and are then adjusted to The Japan Meteorological Agency (JMA) has the 1981 – 2010 baseline. The observatories at Miyazaki published the Annual Report on the Climate System on and Iida were relocated in May 2000 and May 2002, the Tokyo Climate Center website1 since 2007. The aim respectively. For these stations, any discontinuity in the of such provision is to share information on the climate temperature time series is adjusted to cancel out the system and recent related conditions with national influence of the moves. meteorological services, research institutes, universities and other interested parties. 1.2.2 Climatological normal and rank This report summarizes 2016 climatic characteristics The seasonal characteristics of Japan’s climate are and climate system conditions worldwide, with coverage summarized in Section 2.1, which reports temperature of specific events including the effects of the summer anomalies, precipitation ratios and sunshine duration 2014 – spring 2016 El Niño event and notable aspects of ratios derived from daily observations made at 154 Japan’s climate in summer 2016. surface meteorological stations. Regional averages are For more detailed climate information, see the calculated for the four divisions of northern Japan, various products provided via the Tokyo Climate eastern Japan, western Japan and Okinawa/Amami as Center/JMA website at well as for the eleven subdivisions of Hokkaido, Tohoku, http://ds.data.jma.go.jp/tcc/tcc/index.html. Kanto-koshin, Hokuriku, Tokai, Kinki, Chugoku, Shikoku, northern part of Kyushu, southern part of The following sections describe the data sources and Kyushu and Okinawa. For precipitation ratios and analysis methods used in the compilation of this report. sunshine duration ratios, the divisions of northern, Climatological normals are averages for the period from eastern and western Japan are further divided into the 1981 to 2010. Unless otherwise noted, anomalies are Pacific side and the Sea of Japan side (Fig. 1.2-1). Tables deviations from normals. on regional climate conditions contain regional averages and rankings of temperature anomalies, precipitation 1.2 Climate in Japan ratios and sunshine duration ratios. The ranking The descriptions in this section mainly relate to categories are “below normal,” “near normal” and Section 2.1. “above normal,” each of which has an equal relative 1.2.1 Average temperature over Japan frequency of occurrence (33%) for the period from 1981 Annual anomalies of the average surface temperature to 2010. The bottom and top 10% of the “below normal” over Japan since 1898 are illustrated in Section 2.1.1. and “above normal” categories are defined as The anomalies shown are calculated from temperatures “significantly below normal” and “significantly above recorded at 15 meteorological observatories (Abashiri, normal,” respectively. Nemuro, Suttsu, Yamagata, Ishinomaki, Fushiki, Iida, Choshi, Sakai, Hamada, Hikone, Miyazaki, Tadotsu, Naze and Ishigakijima) selected from among those deemed to be least influenced by the urban heat island 1 http://ds.data.jma.go.jp/tcc/tcc/products/clisys/arcs.html 1 Fig. 1.2-1 Operational climatological regions and station locations 1.3 Climate around the world (NOAA) for the period before 2001. The SSTs are 1° × The descriptions in this section mainly relate to 1° grid values derived from COBE-SST datasets (JMA Section 2.2. The regions used in this report are defined as 2006), and values in areas partly covered by sea ice are shown in Fig. 1.3-1. excluded. In the calculation of global averages, land surface temperature anomalies and SST anomalies 1.3.1 Global average temperature against the 1971 – 2000 baseline are incorporated into 5° Annual anomalies of the global average surface × 5° grid values, which are weighed in proportion to the temperature since 1891 are illustrated in Section 2.2.1. area of the relevant grids, and the grid values are The anomalies shown are derived from a combined averaged over the globe. The global averages are dataset of near-surface air temperatures over land and sea adjusted to the 1981 – 2010 baseline. The annual values surface temperatures (SSTs). The over-land air are accompanied by 90% confidence intervals based on temperatures are based on on-site observation data estimated errors attributable to the inhomogeneity of data derived from monthly CLIMAT reports for the period availability (Ishihara 2007). from 2001 onward, and from Global Historical Climate Network (GHCN) datasets produced by the National Oceanographic and Atmospheric Administration 2 1.3.2 Data and climatological normals precipitation are calculated by dividing the total number Figures on world climatic conditions are based on of extreme events observed at stations by the total CLIMAT reports. Historical datasets are derived from number of available observation data for each 5° × 5° GHCN datasets and CLIMAT reports (from June 1982 grid box. Frequencies are represented by semicircles. For onward, prior to GHCN datasets). grid boxes where fewer than ten observations are Data and information on disasters are based on available, no semicircle is shown. Since the frequency of official reports from the United Nations and national extreme events is expected to be about 3% on average, governments, and from databases of research institutes occurrence is considered to be above normal when the (Emergency Events Database (EM-DAT)). figure is 10% or more. 1.3.3 Extreme climate events 1.4 Atmospheric circulation JMA defines an extreme climate event as a The descriptions in this section mainly relate to phenomenon likely to happen only once every 30 years Sections 2.3, 2.4, 2.6, 2.7 and 2.8 and Chapter 3. or longer. For monthly/seasonal mean temperatures, extremely high (or low) temperatures are deemed to be 1.4.1 Data and climatological normals those with an anomaly greater than 1.83 times the Atmospheric circulation data are based on the results standard deviation based on the period 1981 – 2010. For of six-hourly global objective analysis conducted at 00, monthly/seasonal precipitation totals, extremely heavy 06, 12 and 18 UTC using data from the Japanese 55-year (or light) precipitation is that above (or below) any value reanalysis (JRA-55; Kobayashi et al. 2015). The normal observed during the period 1981 – 2010. is the 1981 – 2010 average of JRA-55 data (JMA 2011). 1.3.4 Annual figures 1.4.2 Atmospheric circulation and convection For annual mean temperature anomalies shown in Wave activity flux (Takaya and Nakamura