{"id":1622,"date":"2017-08-31T16:18:44","date_gmt":"2017-08-31T07:18:44","guid":{"rendered":"http:\/\/aplpubweb.jamstec.go.jp\/climate\/?p=1622"},"modified":"2017-08-31T16:18:44","modified_gmt":"2017-08-31T07:18:44","slug":"climate-watch-august-2017-edition-facing-fall","status":"publish","type":"post","link":"http:\/\/aplpubweb.jamstec.go.jp\/climate\/?p=1622","title":{"rendered":"Climate Watch \u2013 August 2017 Edition: Facing fall"},"content":{"rendered":"<p><em>Quick summary:<\/em><\/p>\n<ul>\n<li><em>neutral conditions in the tropical Pacific predicted until end of the year<\/em><\/li>\n<li><em>strong positive Indian Ocean Dipole predicted to develop until fall<\/em><\/li>\n<li><em>enhanced risk of drought in Indonesia and Australia<\/em><\/li>\n<li><em>outlook for Japan: slightly warmer and drier than average in fall<\/em><\/li>\n<\/ul>\n<figure id=\"attachment_1623\" aria-describedby=\"caption-attachment-1623\" style=\"width: 640px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-1623\" src=\"http:\/\/aplpubweb.jamstec.go.jp\/climate\/wp-content\/uploads\/2017\/08\/fig_0_201708-1.jpg\" alt=\"\" width=\"650\" height=\"679\" srcset=\"http:\/\/aplpubweb.jamstec.go.jp\/climate\/wp-content\/uploads\/2017\/08\/fig_0_201708-1.jpg 650w, http:\/\/aplpubweb.jamstec.go.jp\/climate\/wp-content\/uploads\/2017\/08\/fig_0_201708-1-287x300.jpg 287w, http:\/\/aplpubweb.jamstec.go.jp\/climate\/wp-content\/uploads\/2017\/08\/fig_0_201708-1-144x150.jpg 144w\" sizes=\"auto, (max-width: 650px) 100vw, 650px\" \/><figcaption id=\"caption-attachment-1623\" class=\"wp-caption-text\">A rare circumzenith arc (also called upside-down rainbow) sighted from the Yokohama campus<\/figcaption><\/figure>\n<p>After taking a little break, hot summer temperatures are back in Japan. According to the <a href=\"http:\/\/www.jma.go.jp\/jma\/indexe.html\">JMA<\/a>, temperatures in northern and western Japan were above average in July, with northern Japan also having above average sunshine hours (<a href=\"http:\/\/www.jma.go.jp\/jma\/press\/1708\/01a\/tenko1707.html\">link to the Japanese website<\/a>). From early to mid-August, however, unseasonably cool temperatures occurred in eastern and northern Japan. This appears to have been due to the strengthening of the Okhotsk High (a high pressure system over the Sea of Okhotsk, north of Japan), which is linked with cool northeasterly winds blowing toward Japan (also known as Yamase winds; <a href=\"http:\/\/www.jma.go.jp\/jma\/press\/1708\/17a\/japan20170817.html\">link to JMA explanation [in Japanese]<\/a>).<\/p>\n<p>In western Japan, on the other hand, hot temperatures have continued unabated throughout August. This is at least partly due to the influence of the positive <a href=\"http:\/\/www.jamstec.go.jp\/frcgc\/research\/d1\/iod\/e\/iod\/about_iod.html\">Indian Ocean Dipole<\/a> (IOD) that continues developing in the tropical Indian Ocean.<\/p>\n<figure id=\"attachment_1624\" aria-describedby=\"caption-attachment-1624\" style=\"width: 3053px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-1624\" src=\"http:\/\/aplpubweb.jamstec.go.jp\/climate\/wp-content\/uploads\/2017\/08\/fig_1_201708_engl.png\" alt=\"\" width=\"3063\" height=\"1905\" srcset=\"http:\/\/aplpubweb.jamstec.go.jp\/climate\/wp-content\/uploads\/2017\/08\/fig_1_201708_engl.png 3063w, http:\/\/aplpubweb.jamstec.go.jp\/climate\/wp-content\/uploads\/2017\/08\/fig_1_201708_engl-300x187.png 300w, http:\/\/aplpubweb.jamstec.go.jp\/climate\/wp-content\/uploads\/2017\/08\/fig_1_201708_engl-650x404.png 650w, http:\/\/aplpubweb.jamstec.go.jp\/climate\/wp-content\/uploads\/2017\/08\/fig_1_201708_engl-241x150.png 241w\" sizes=\"auto, (max-width: 3063px) 100vw, 3063px\" \/><figcaption id=\"caption-attachment-1624\" class=\"wp-caption-text\">Figure 1. Predicted surface air temperature anomaly (in \u00b0C; average September-November). The prediction was initiated on August 1.<\/figcaption><\/figure>\n<p>Let\u2019s take a look at the latest predictions. <a href=\"http:\/\/www.jamstec.go.jp\/frcgc\/research\/d1\/iod\/e\/seasonal\/outlook.html\">According to the SINTEX-F model<\/a>, surface air temperatures over land will be above average over most land areas from September through November. One notable exception is central Russia. In difference to last month\u2019s forecast, only slightly cooler than average temperatures are predicted over the US.<\/p>\n<figure id=\"attachment_1625\" aria-describedby=\"caption-attachment-1625\" style=\"width: 3169px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-1625\" src=\"http:\/\/aplpubweb.jamstec.go.jp\/climate\/wp-content\/uploads\/2017\/08\/fig_2_201708_engl.png\" alt=\"\" width=\"3179\" height=\"1897\" srcset=\"http:\/\/aplpubweb.jamstec.go.jp\/climate\/wp-content\/uploads\/2017\/08\/fig_2_201708_engl.png 3179w, http:\/\/aplpubweb.jamstec.go.jp\/climate\/wp-content\/uploads\/2017\/08\/fig_2_201708_engl-300x179.png 300w, http:\/\/aplpubweb.jamstec.go.jp\/climate\/wp-content\/uploads\/2017\/08\/fig_2_201708_engl-650x388.png 650w, http:\/\/aplpubweb.jamstec.go.jp\/climate\/wp-content\/uploads\/2017\/08\/fig_2_201708_engl-251x150.png 251w\" sizes=\"auto, (max-width: 3179px) 100vw, 3179px\" \/><figcaption id=\"caption-attachment-1625\" class=\"wp-caption-text\">Figure 2. Predicted rainfall anomalies (in mm\/day; average September-November). The prediction was initiated on August 1.<\/figcaption><\/figure>\n<p>Rainfall predictions have not changed much from last month. For the period September through November above average rainfall is predicted over tropical Africa. Below average rainfall is predicted for Indonesia, Australia, and most of Brazil.<\/p>\n<p>For Japan, the model predicts warmer than average conditions in fall. Please bear in mind though that the model\u2019s forecast skill in the mid and high latitudes is rather limited.<\/p>\n<figure id=\"attachment_1626\" aria-describedby=\"caption-attachment-1626\" style=\"width: 3314px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-1626\" src=\"http:\/\/aplpubweb.jamstec.go.jp\/climate\/wp-content\/uploads\/2017\/08\/fig_3_201708_engl.png\" alt=\"\" width=\"3324\" height=\"1899\" srcset=\"http:\/\/aplpubweb.jamstec.go.jp\/climate\/wp-content\/uploads\/2017\/08\/fig_3_201708_engl.png 3324w, http:\/\/aplpubweb.jamstec.go.jp\/climate\/wp-content\/uploads\/2017\/08\/fig_3_201708_engl-300x171.png 300w, http:\/\/aplpubweb.jamstec.go.jp\/climate\/wp-content\/uploads\/2017\/08\/fig_3_201708_engl-650x371.png 650w, http:\/\/aplpubweb.jamstec.go.jp\/climate\/wp-content\/uploads\/2017\/08\/fig_3_201708_engl-263x150.png 263w\" sizes=\"auto, (max-width: 3324px) 100vw, 3324px\" \/><figcaption id=\"caption-attachment-1626\" class=\"wp-caption-text\">Figure 3. Predicted SST anomalies (in \u00b0C) for September-November. The prediction was initiated on August 1.<\/figcaption><\/figure>\n<p>Sea-surface temperatures (SSTs) in the tropical Pacific are predicted to be just slightly above average during September through November. This is somewhat weaker than last month\u2019s prediction so we decided to call for neutral conditions.<\/p>\n<p>In the Indian Ocean, on the other hand, the model continues to predict the development of a strong positive <a href=\"http:\/\/www.jamstec.go.jp\/frcgc\/research\/d1\/iod\/e\/iod\/about_iod.html\">Indian Ocean Dipole<\/a> (IOD) event, with cooler than average SSTs in the east, and warmer than average SSTs in the west. Positive IOD events <a href=\"https:\/\/www.jamstec.go.jp\/frsgc\/eng\/press\/IOD\/index.html\">typically lead to warmer than average temperatures in western Japan<\/a>. The model prediction suggests that the remote impacts of the positive IOD will continue to strengthen the <a href=\"http:\/\/glossary.ametsoc.org\/wiki\/Ogasawara_high\">Ogasawara High<\/a> (also called Bonin high), leading to warmer than average temperatures in western Japan during the fall (not shown).<\/p>\n<p>What is the extended outlook for the tropical oceans?<\/p>\n<figure id=\"attachment_1627\" aria-describedby=\"caption-attachment-1627\" style=\"width: 640px\" class=\"wp-caption alignnone\"><img loading=\"lazy\" decoding=\"async\" class=\"size-full wp-image-1627\" src=\"http:\/\/aplpubweb.jamstec.go.jp\/climate\/wp-content\/uploads\/2017\/08\/fig_4_201708_engl.png\" alt=\"\" width=\"650\" height=\"885\" srcset=\"http:\/\/aplpubweb.jamstec.go.jp\/climate\/wp-content\/uploads\/2017\/08\/fig_4_201708_engl.png 650w, http:\/\/aplpubweb.jamstec.go.jp\/climate\/wp-content\/uploads\/2017\/08\/fig_4_201708_engl-220x300.png 220w, http:\/\/aplpubweb.jamstec.go.jp\/climate\/wp-content\/uploads\/2017\/08\/fig_4_201708_engl-110x150.png 110w\" sizes=\"auto, (max-width: 650px) 100vw, 650px\" \/><figcaption id=\"caption-attachment-1627\" class=\"wp-caption-text\">Figure 4. Time evolution of the Nino 3.4 (upper panel) and IOD (lower panel) indices (in \u00b0C). The blue lines show the observations. The predictions (initiated on August 1) are shown for individual ensemble members with perturbed initial conditions (grey lines) and their average (red lines).<\/figcaption><\/figure>\n<p>Figure 4 shows two SST indices of interest. The Ni\u00f1o 3.4 index is predicted to be slightly above average until spring of next year (red line in the upper panel of Fig. 4). Thereafter, temperatures are expected to be slightly cooler than average until the end of the forecast period. The weakness of the predicted temperature anomalies suggests that neutral conditions will prevail until the summer of 2018.<\/p>\n<p>The IOD index is predicted to exceed +1 \u00b0C in August (Fig. 4, lower panel) and peak at about +1.3 \u00b0C in September and October.<\/p>\n<p>A few more remarks on the remote impacts of the IOD. As noted above, positive IOD events tend to bring high surface pressure to Japan, with warmer than average temperatures and lower than average rainfall. The currently predicted tropical SST pattern (neutral Pacific + positive IOD) has precedents in the recent past. <a href=\"https:\/\/www.jamstec.go.jp\/frsgc\/eng\/press\/IOD\/index.html\">In 1994<\/a>, Japan was under the influence of high pressure systems that reduced rainfall and contributed to record breaking heat waves. <a href=\"https:\/\/www.nature.com\/articles\/srep17252\">In 2006<\/a>, Australia was hit by an extremely severe drought that devastated the wheat harvest. The current predictions therefore raise the concern for droughts in Indonesia and Australia.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Quick summary: neutral conditions in the tropical Pacific predicted until end of the year strong positive Indi &#8230; <a title=\"Climate Watch \u2013 August 2017 Edition: Facing fall\" class=\"read-more\" href=\"http:\/\/aplpubweb.jamstec.go.jp\/climate\/?p=1622\" aria-label=\"Climate Watch \u2013 August 2017 Edition: Facing fall \u306b\u3064\u3044\u3066\u3055\u3089\u306b\u8aad\u3080\">\u7d9a\u304d\u3092\u8aad\u3080<\/a><\/p>\n","protected":false},"author":4,"featured_media":1623,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[19],"tags":[],"class_list":["post-1622","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category--en"],"_links":{"self":[{"href":"http:\/\/aplpubweb.jamstec.go.jp\/climate\/index.php?rest_route=\/wp\/v2\/posts\/1622","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/aplpubweb.jamstec.go.jp\/climate\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/aplpubweb.jamstec.go.jp\/climate\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/aplpubweb.jamstec.go.jp\/climate\/index.php?rest_route=\/wp\/v2\/users\/4"}],"replies":[{"embeddable":true,"href":"http:\/\/aplpubweb.jamstec.go.jp\/climate\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1622"}],"version-history":[{"count":4,"href":"http:\/\/aplpubweb.jamstec.go.jp\/climate\/index.php?rest_route=\/wp\/v2\/posts\/1622\/revisions"}],"predecessor-version":[{"id":1631,"href":"http:\/\/aplpubweb.jamstec.go.jp\/climate\/index.php?rest_route=\/wp\/v2\/posts\/1622\/revisions\/1631"}],"wp:featuredmedia":[{"embeddable":true,"href":"http:\/\/aplpubweb.jamstec.go.jp\/climate\/index.php?rest_route=\/wp\/v2\/media\/1623"}],"wp:attachment":[{"href":"http:\/\/aplpubweb.jamstec.go.jp\/climate\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1622"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/aplpubweb.jamstec.go.jp\/climate\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1622"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/aplpubweb.jamstec.go.jp\/climate\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1622"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}