No. 50

Autumn 2017
Contents

P a geFrom the editor

1

El Niño Outlook (November 2017 – May 2018)

2

JM A’s Seasonal Numerical Ensemble Prediction for Winter 2017/20184

Cold Season Outlook for Winter 2017/2018 in Japan

6

Summary of Asian Summer Monsoon 2017

7

Status of the Antarctic Ozone Hole in 201710

Unusual weather conditions in Japan during the first half of August 201711

TCC contributions to Regional Climate Outlook Forums

12

The Fifth Session of the East Asia winter Climate Outlook Forum (EASCOF-5)

13

Update of website on RA II Information Sharing for Climate Services

14

From the editor
nities for TCC to interact directly with users engaging inclimate services with TCC products and to collect related
feedback. Such input contributes significantly to the improvement of TCC products and RCOF activities. With
respect to RCOFs, this issue reports on the WMO Workshop on Global Review of RCOFs held in September 2017.
TCC News is thus expected to be useful in exchanges ofclimate-related information.
Since its 2009 designation as an RA II WMO Regional
Climate Center, the Center has advanced its NMHS support via the provision of tools, data and products, e.g., a
web-based climate analysis application, iTacs (Interactive
Tool for Analysis of the Climate System), the Japan Meteorological Agency’s (JMA’s) reanalysis data (current
version: JRA-55) as fundamental data for climate analysis
and monitoring, early warning products for extreme
weather events and the Monthly Discussion on Seasonal
Climate Outlook.
Toward the establishment of the Global Framework for
Climate Services (GFCS), JMA held an event titled “Tokyo Climate Conference: Better Climate Information for a
Safe and Sustainable Society“ in Tokyo, Japan, in July
2009, to support collaboration among relevant bodies toward the establishment of a new international framework
for climate services. Today the GFCS represents a leading
WMO priority under which NMHSs play a key role inproviding high-quality, high-precision climate information
based on user needs. In this context, it is important to share
information on climate services, good practices and lessons
learned in climate information usage.

Thank you for reading this landmark 50th issue of the
TCC (Tokyo Climate Center) News. TCC has provided
these quarterly updates to climate experts at National Meteorological and Hydrological Services (NMHSs) andelsewhere worldwide since July 2005 prior to its 2009 RA
II WMO Regional Climate Center (RCC) designation.
TCC News has covered areas ranging from regular climate
information (seasonal forecasts, the ENSO outlook andclimate monitoring, including sea ice and atmosphericozone conditions) to newly developed TCC products, including geostationary meteorological satellite data. The
publication thus represents an effective outlet for updates
on TCC activities.
As well as providing information on technological matters, TCC News highlights capacity building based on annual training seminars and expert visits among other topics. As part of its RCC development efforts, the Center
also holds annual training seminars on the application of
its climate monitoring and prediction products. A total of
127 experts in the region have attended these seminars
since their introduction in 2008 (as of November 2017).
Since 2006, TCC has also arranged 20 visits by TCC experts to NMHSs for discussions on collaboration, technicaltransfer and training seminars. Thanks are due to the relevant NMHSs for their involvement in these activities. Other areas of assistance include contribution to Regional
Climate Outlook Forums (RCOFs), in which TCC has participated by sending experts and/or providing seasonal
forecast materials. RCOFs also provide valuable opportunities

TCC News

1

No. 50 | Autumn 2017learned in climate information usage. TCC operates a dedicated website for this purpose, thereby helping to improveclimate services in RA II (see also the website update article in this newsletter).

TCC News will hopefully help to promote active communication among climate operators and support the provision of climate services by Asia Pacific NMHSs.
(Kiyotoshi Takahashi, Head of Tokyo Climate Center)

El Nino Outlook (November 2017 – May 2018)
The continuation of the below-normal NINO.3 SST until
boreal winter is likely (60%) to meet JMA's definition of a La
Niña event, although the criterion may not be met (40%).
(Article based on the El Niño outlook issued on 10 November 2017.)

Western Pacific and Indian Ocean
The area-averaged SST in the tropical western Pacific(NINO.WEST) region was above normal in October. Values are likely to be generally near normal until boreal winter.
The area-averaged SST in the tropical Indian Ocean(IOBW) region was near normal in October. Values arelikely to be near or below normal until boreal winter.

El Niño/La Niña
In October 2017, the NINO.3 SST was below normal
with a deviation of -0.6°C. SSTs in October were below
normal in the central and eastern equatorial Pacific (Figures 1 and 3(a)). Subsurface temperatures were below
normal in the central and eastern equatorial Pacific (Figures 2 and 3(b)). Atmospheric convective activity was below normal near the date line over the equatorial Pacific,
and easterly winds in the lower troposphere (trade winds)
were stronger than normal over the central equatorial Pacific. These oceanic and atmospheric conditions indicatethat common characteristics of past La Niña events persisted in October.
Cold subsurface waters in the central and eastern equatorial Pacific are likely to move eastward, supporting cooler-than-normal SST conditions in the eastern part. JMA's
El Niño prediction model suggests that the NINO.3 SST
will remain below normal until winter. During late winterand spring, its value is expected to approach the normal,
and prediction uncertainty will gradually increase (Figure4). In conclusion, it is more likely (60%) that continuationof below-normal NINO.3 SST until boreal winter willmeet the JMA's definition of La Niña event, although it ispossible (40%) that the criterion will not be met (Figure 5).

(Ichiro Ishikawa, Climate Prediction Division)* The SST normal for the NINO.3 region (5°S – 5°N,
150°W – 90°W) is defined as an monthly average over thelatest sliding 30-year period (1987-2016 for this year).
Based on this normal, JMA judges an El Niño (La Niña)
event when the five-month running mean of the NINO.3
SST deviates from the normal by +0.5°C (-0.5°C) or more(less) for six months or more.
* The SST normals for the NINO.WEST region (Eq. –15°N, 130°E – 150°E) and the IOBW region (20°S – 20°N,
40°E – 100°E) are defined as linear extrapolations withrespect to the latest sliding 30-year period, in order to remove the effects of significant long-term warming trends
observed in these regions.

(b)

(a)

Figure 1 Monthly mean (a) sea surface temperatures (SSTs) and (b) SST anomalies in the Indian and Pacific
Ocean areas for October 2017
The contour intervals are 1˚C in (a) and 0.5˚C in (b). The base period for the normal is 1981 – 2010.

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No. 50 | Autumn 2017

(a)

(b)

Figure 2 Monthly mean depth-longitude cross sections of (a) temperatures and (b) temperature anomalies in theequatorial Indian and Pacific Ocean areas for October 2017
The contour intervals are 1˚C in (a) and 0.5˚C in (b). The base period for the normal is 1981 – 2010.

(a)

(b)

Figure 3
Time-longitude cross sections of (a) SST and (b) ocean heat content (OHC) anomalies along the equatorin the Indian and Pacific Ocean areas
OHCs are defined here as vertical averaged temperatures in the top 300 m. The base period for the normal is 1981 – 2010.

Figure 5 ENSO forecast probabilities based on the El
Niño prediction model
Red, yellow and blue bars indicate probabilities that the
five-month running mean of the NINO.3 SST deviationfrom the latest sliding 30-year mean will be +0.5°C or
above (El Niño), between +0.4 and -0.4°C (ENSO-neutral)and -0.5°C or below (La Niña), respectively. Regular text
indicates past months, and bold text indicates current andfuture months.

Figure 4 Outlook of NINO.3 SST deviation producedby the El Niño prediction modelThis figure shows a time series of monthly NINO.3 SST
deviations. The thick line with closed circles shows observed SST deviations, and the boxes show the values
produced for up to six months ahead by the El Niño prediction model. Each box denotes the range into which the
SST deviation is expected to fall with a probability of 70%.

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No. 50 | Autumn 2017

JMA’s Seasonal Numerical Ensemble Prediction for Winter 2017/2018
Based on JMA’s seasonal ensemble prediction system,sea surface temperature (SST) anomalies are predicted to be
below normal in the equatorial Pacific during boreal winter2017/2018, suggesting La Niña-like conditions. In association with these conditions, inactive convection is predicted
over the equatorial Pacific, while active convection is predicted over the region from the Bay of Bengal across the
Indochina Peninsula and the South China Sea to the Philippines. The Aleutian Low is predicted to be weaker than normal over the sea off the western coast of North America,
while the Siberian High is predicted to be slightly stronger
than normal over the region from the southeastern edge ofChina to the southern part of Japan. However, colder conditions associated with the slightly stronger Siberian Highmay be offset by global warming trends and thickness over
the Northern Hemisphere.

3.

Prediction for the tropics and sub-tropics (Figure 7)
Figure 7 (a) shows predicted precipitation (contours) andrelated anomalies (shading) for DJF. Above-normal anomalies are predicted over the latitudinal band of about 5 –15°N in the North Pacific in association with warmer-than-normal SSTs, while below-normal anomalies are
predicted over the equatorial Pacific in association withcolder-than-normal SSTs.

(a)

1.

Introduction
This article outlines JMA’s dynamical seasonal ensemble prediction for boreal winter 2017/2018 (December –February, referred to as DJF), which was used as a basis
for JMA’s operational cold-season outlook issued on 24
November 2017. The outlook is based on the seasonal ensemble prediction system of the Coupled Atmosphere-ocean General Circulation Model (CGCM). See thecolumn below for system details.
Section 2 outlines global SST anomaly predictions, andSection 3 describes the associated circulation field predictions for the tropics and sub-tropics. Finally, the circulation
fields predicted for the mid- and high-latitudes of theNorthern Hemisphere are discussed in Section 4.

(b)

(c)

2.

SST anomalies (Figure 6)
Figure 6 shows predicted SSTs (contours) and related
anomalies (shading) for DJF. For SST conditions in thetropical Pacific, below normal anomalies are predicted in
the equatorial Pacific, suggesting La Niña-like conditions.
Conversely, above-normal anomalies are predicted in thelatitudinal band of about 5 – 15°N in the North Pacific,
representing a minimal northern spread of La Niña-like
conditions. Meanwhile, normal SST conditions are predicted in the Indian Ocean.

(d)Figure 7 Predicted atmospheric fields from 60°N –60°S for December–February 2017/2018 (ensemble
mean of 51 members)(a) Precipitation (contours) and anomaly (shading). The
contour interval is 2 mm/day.
(b) Velocity potential at 200 hPa (contours) and anomaly(shading). The contour interval is 2 × 106 m2/s.
(c) Stream function at 200 hPa (contours) and anomaly(shading). The contour interval is 16 × 106 m2/s.
(d) Stream function at 850 hPa (contours) and anomaly(shading). The contour interval is 5 × 106 m2/s.

Figure 6 Predicted SSTs (contours) and SST anomalies (shading) for December–February 2017/2018 (ensemble mean of 51 members)

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No. 50 | Autumn 2017

Figure 7 (b) shows predicted velocity potential (contours) and related anomalies (shading) at the upper troposphere (200 hPa) for DJF. Positive (i.e., convergent)anomalies are predicted over the equatorial Pacific in association with light precipitation. Conversely, negative (i.e.,
divergent) anomalies are predicted over the region fromthe Bay of Bengal across the Indochina Peninsula and thearea from the South China Sea to the Philippines.
Figure 7 (c) shows predicted stream functions (contours)
and related anomalies (shading) at the upper troposphere(200 hPa) for DJF. Positive (i.e., anticyclonic) anomalies
are predicted in the most of the Northern Hemisphere, indicating a northward-shift tendency for the subtropical jet
stream. Focusing on the strength of positive anomalies,
anticyclonic anomalies are expected over China in association with active convection in and around the South China
Sea and the Philippines. Conversely, equatorial symmetric
negative (i.e., cyclonic) anomalies are predicted over theeastern part of the tropical Pacific in association with La
Niña like conditions.
Figure 7 (d) shows predicted stream functions (contours)
and related anomalies (shading) at the lower troposphere(850 hPa) for DJF. Negative (i.e., cyclonic) anomalies are
predicted in and around the South China Sea and the Philippines in association with heavier-than-normal precipitation. Conversely, positive anomalies are seen over the sea
off the western coast of North America in association with
the negative phase of the Pacific North America (PNA)
teleconnection as clearly observed during past La Niña
events.

the PNA teleconnection, suggesting a weaker-than-normal
Aleutian Low. Meanwhile, small negative anomalies arealso predicted over most of China and the southern part ofSiberia, suggesting a slightly weaker-than-normal SiberianHigh. However, this should be interpreted with caution due
to significant uncertainty. Conversely, small positive
anomalies are predicted over the region from the southeastern edge of China to the southern part of Japan, suggesting a slightly stronger-than-normal Siberian High.
However, normal surface temperatures are expected inthese regions because the colder conditions associated withthis slight increase may be offset by global warming trends
and high thickness over the Northern Hemisphere.
(Takashi Yamada, Climate Prediction Division)

(a)

(b)

4. Prediction for the mid- and high- latitudes of theNorthern Hemisphere
Figure 8 (a) shows predicted geopotential heights (contours) and related anomalies (shading) at 500 hPa for DJF.
Positive anomalies are predicted over most of the Northern
Hemisphere in association with global warming trends andhigh thickness related to active convection over warm SST
conditions in the latitudinal band of about 5 – 15°N in the
North Pacific. Focusing on the strength of positive anomalies, large positive anomalies are seen over the sea off thewestern coast of North America in association with thenegative phase of the PNA teleconnection.
Figure 8 (b) shows predicted sea level pressure (contours) and related anomalies (shading) for DJF. Positive
anomalies are predicted over the sea off the western coastof North America in association with the negative phase of
the PNA…..

Figures 8 Predicted atmospheric fields from 20°N –90°N for December–February 2017/2018 (ensemble
mean of 51 members)(a) Geopotential height at 500 hPa (contours) and anomaly(shading). The contour interval is 60 m.
(b) Sea level pressure (contours) and anomaly (shading).
The contour interval is 4 hPa.

JMA’s Seasonal Ensemble Prediction System
JMA operates a seasonal Ensemble Prediction System (EPS) using the Coupled atmosphere-ocean General Circulation
Model (CGCM) to make seasonal predictions beyond a one-month time range. The EPS produces perturbed initial conditions by means of a combination of the initial perturbation method and the lagged average forecasting (LAF) method.
The prediction is made using 51 members from the latest four initial dates (13 members are run every 5 days). Details of
the prediction system and verification maps based on 30-year hindcast experiments (1981–2010) are available at
http://ds.data.jma.go.jp/tcc/tcc/products/model/.

TCC News5

No. 50 | Autumn 2017Cold Season Outlook for Winter 2017/2018 in JapanJMA issued its outlook for the coming winter (December
2017 – February 2018) over Japan in September and updated
it in October based on the Agency’s seasonal Ensemble Prediction System (EPS). This article outlines the outlook updateof 25 October.
1. Outlook summary (Figure 9)
 In northern Japan, seasonal mean temperatures are
expected to exhibit above-normal tendencies and seasonal snowfall amounts for the Sea of Japan side are
expected to exhibit below-normal tendencies due toenhanced
low-pressure
systems
andweaker-than-normal cold-air advection from higher latitudes. Seasonal precipitation amounts for the Pacificside of northern Japan are expected to exhibit
above-normal tendencies.
 In western Japan, seasonal snowfall and precipitation
amounts for the Sea of Japan side are expected to exhibit above-normal tendencies due to significant influences of cold-air inflow from the continent.
2. Outlook backgroundFigure 10 highlights expected large-scale oceanic/atmospheric characteristics for winter. An outline of the
background to the outlook is given below.












It is equally likely that La Niña conditions will develop in boreal autumn or winter and that ENSO-neutral
conditions will persist until boreal winter. Accordingly, sea surface temperatures (SSTs) are expected to be
above normal over the western tropical Pacific.
In association with the expected SST anomalies in thetropics, convection over the tropics is expected to beenhanced from the Indian Ocean to Southeast Asia,
especially around the Philippines, and suppressedaround the date line.
In upper circulation fields, the jet stream is expected tomeander northward over southern China and southward to the east of Japan. This pattern tends to appear
when SSTs over the western tropical Pacific are above
normal.
The Siberian High is expected to be stronger thannormal in its southeastern part in association withnorthward meandering of the jet stream over southern
China, indicating a strong winter monsoon from eastern/western Japan to Okinawa/Amami.
Around northern Japan, low-pressure system activity is
expected to be enhanced, while cold-air advection is
expected to be weaker than normal in association withenhanced convective activity around the Philippines.
Overall temperatures in the troposphere are expected
to be above-normal over the Northern Hemisphere inassociation with the prevailing long-term trend.

Figure 9 Outlook for winter 2017/2018 temperature(above) and precipitation (below) probability in Japan.

Figure 10 Conceptual diagram showing expectedlarge-scale ocean/atmosphere characteristics for winter2017/2018(Hiroshi Ohno, Climate Prediction Division)

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Summary of the 2017 Asian Summer Monsoon
1. Precipitation and temperature
Four-month total precipitation amounts based on CLIMAT reports during the monsoon season (June – September) were more than 140% of the normal in and around
India and from southern Philippines to the New Guinea
Island. Conversely, the corresponding figures were lessthan 60% of the normal from the Korean Peninsula tonortheastern China, in northwestern China and southwestern Pakistan (Figure 11). In August, monsoonal heavy raincausing flooding and landslides in Bangladesh, India and
Nepal resulted in more than total 1,800 fatalities. From the
Korean Peninsula to northeastern China, extremely low
precipitation totals were observed in July and September,with South Korea recording the third-lowest July amountsince KMA observation began in 1973.
Four-month mean temperatures for the same period
were more than 1°C above normal in western Mongolia,
eastern China and the Korean Peninsula, and slightly below normal in and around India, and in the western part ofIndochina Peninsula (Figure 12). In mid and late July,
China experienced extreme heatwave conditions from its
central to eastern provinces, with temperatures reaching
42°C in parts of Hebei, Shaanxi, Shanxi and Xinjiang on
July 13 according to CMA.

Figure 11 Four-month precipitation ratios (%) from
June to September 2017
The base period for normal is 1981 – 2010. Note that thedata in Vietnam, Thailand and Cambodia are interpolated
due to the lack of CLIMAT report or climatological normal.

2. Tropical cyclones
A total of 19 tropical cyclones (TCs1) had formed over
the western North Pacific up to September 2017 as compared to the normal of 18.4. July’s total of 8 represented asignificant increase over the normal of 3.6 (Table 1). From
June to September, a total 10 TCs hit the area from southern China to the Indochina Peninsula over the South China
Sea. Among these, Typhoons Hato and Pakhar made landfall in series late August in almost the same location insouthern China, resulting in more than 120 total fatalities(sources: Government of China, Government of Macau).
Typhoon Noru had JMA’s second-longest duration (19.0
days) since 1951, forming on July 20 near Minami Torishima Island and degrading to extratropical cyclone status
on August 8 over the Sea of Japan. Noru drifted over a
warm SST region southeast of Japan for most of its lifetime due to interaction known as the Fujiwara effect with
Typhoon Kulap and weak steering flow from the Western
North Pacific subtropical high located far to its east.

Figure 12 Four-month mean temperature anomalies(°C) from June to September 2017
The base period for normal is 1981 – 2010. Note that thedata in Vietnam, Thailand and Cambodia are interpolated
due to the lack of CLIMAT report or climatological normal.
Table 1 Tropical cyclones forming over the western
North Pacific up to September 2017

3. Monsoon activity and atmospheric circulation
Convective activity (inferred from OLR) averaged forJune – September 2017 was enhanced over the Maritime
Continent, from east China to the Indochina Peninsula andIndia, and was suppressed over the equatorial Indian
Ocean, over the Bay of Bengal and from southern China to
the seas east of the Philippines (Figure 13).

Note: Based on information from the RSMC Tokyo-Typhoon Center.
1) Intensity classification for tropical cyclones
TS: tropical storm, STS: severe tropical storm, TY: typhoon2) Estimated maximum 10-minute mean wind

1 Here, a TC is defined as a tropical cyclone with a maximum sustained
wind speed of 34 knots or more.

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Zonal wind shear between the upper and lower troposphere over the North Indian Ocean and southern Asia
(Figure 15) was stronger than normal from the second halfof June to the first half of July and from September to thefirst half of October.
Convective activity over the Maritime Continent wasenhanced throughout the summer monsoon season andsuppressed over the Philippines from early to mid-August(Figure 16). During this period, the Pacific High did notexhibit its usual extension to mainland Japan and wasshifted southward of its normal position, corresponding to
the negative PJ (Pacific – Japan) pattern (Nitta 1987;
Kosaka and Nakamura 2010) (Figure17).

OLR index data (Table 2) indicate that the overall activityof the Asian summer monsoon (represented by the SAMOI(A) index) was below normal in June and was above normal in July and October. The most active convection area
was shifted northward of its normal position in June andOctober (see the SAMOI (N) index.) and eastward in October (see the SAMOI (W) index.).
In the upper troposphere, the Tibetan High was stronger
than normal (Figure 14 (a)). In the lower troposphere, themonsoon trough over Southeast Asia was weaker thannormal and anti-cyclonic circulation anomalies straddlingthe equator were seen over the western Pacific (Figure 14(b)).

(Section 1 and 2: Kenji Kamiguchi, 3: Hiroki Togawa,Climate Prediction Division)

Figure 13 Four-month mean OLR and its anomaly
for June–September 2017
The contours indicate OLR at intervals of 10 W/m2, andthe color shading denotes OLR anomalies from the normal(i.e., the 1981–2010 average). Negative (cold color) andpositive (warm color) OLR anomalies show enhanced andsuppressed convection compared to the normal, respectively. Original data are provided by NOAA.

Table 2 Summer Asian Monsoon OLR Index (SAMOI) values observed from May to October 2017
Asian summer monsoon OLR indices (SAMOI) are derived from OLR anomalies from May to October. SAMOI (A), (N)and (W) indicate the overall activity of the Asian summer monsoon, its northward shift and its westward shift, respectively. SAMOI definitions are as follows: SAMOI (A) = (-1) × (W + E); SAMOI (N) = S – N; SAMOI (W) = E – W. W,
E, N and S indicate area-averaged OLR anomalies for the respective regions shown in the figure on the right normalized
by their standard deviations.
Summer Asian Monsoon OLR Index (SAMOI)SAMOI (A):Activity

SAMOI (N):SAMOI (W):

Northw ard-shift Westw ard-shift

May 2017

0.7

-0.7

0.4

Jun. 2017

-1.1

1.0

0.3

Jul. 2017

1.7

0.8

-0.7

Aug. 2017

-0.8

-0.2

0.8

Sep. 2017

0.3

-0.9

0.2

Oct. 2017

1.2

1.4

-1.1

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(a)

(b)

Figure 14 Four-month mean stream function and its anomaly for June – September 2017(a) The contours indicate the 200-hPa stream function at intervals of 10 × 106 m2/s, and the color shading indicates
200-hPa stream function anomalies from the normal. (b) The contours indicate the 850-hPa stream function at intervalsof 4 × 106 m2/s, and the color shading indicates 850-hPa stream function anomalies from the normal. The base period forthe normal is 1981 – 2010. Warm (cold) shading denotes anticyclonic (cyclonic) circulation anomalies in the Northern
Hemisphere, and vice-versa in the Southern Hemisphere.

Figure 16 Time-series representation of OLR (W/m2)
averaged over the Philippines (shown by the rectangle
on the bottom: 10°N - 20°N, 115°E - 140°E)
The OLR index is calculated after Wang and Fan (1999).
The thick and thin blue lines indicate seven-day runningmean and daily mean values, respectively. The black line
denotes the normal (i.e., the 1981 - 2010 average), and thegray shading shows the range of the standard deviation
calculated for the time period of the normal.

Figure 15 Time-series representation of the zonal
wind shear index between 200-hPa and 850-hPa averaged over the North Indian Ocean and southern Asia
(the region enclosed by the pink rectangle in the rightfigure: equator – 20°N, 40°E – 110°E)
The zonal wind shear index is calculated after Webster andYang (1992). The thick and thin pink lines indicate seven-day running mean and daily mean values, respectively.
The black line denotes the normal (i.e., the 1981 – 2010average), and the gray shading shows the range of thestandard deviation calculated for the time period of thenormal.

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Figure 17 Sea level pressure (contour) and anomaly(shade) for 01-20 August 2017
The contours indicate sea level pressure at intervals of 2hPa, and the color shading denotes sea level pressureanomalies from the normal (i.e., the 1981–2010 average).

Status of the Antarctic Ozone Hole in 2017
The Antarctic ozone hole in 2017 was less than 20 million
square kilometers in size, representing the smallest coverage for 29 years.
Since the early 1980s, the Antarctic ozone hole has appeared every year in austral spring with a peak in September or early October. It is generally defined as the area inwhich the total ozone column value is below 220 m
atm-cm.
According to JMA’s analysis based on data from the
Ozone Monitoring Instrument (OMI) on the Aura platform,
the Antarctic ozone hole in 2017 appeared early in Augustand expanded rapidly from late August to early September,and then disappeared in mid-November staying smaller
than its most recent decadal average during this time (Figure 18, upper left). Its maximum coverage of 18.8 million
square kilometers (observed on 11 September) was the first
below 20 million square kilometers for 29 years (Figure**, upper right).

18, upper right). The polar vortex over Antarctica was unstable and small in 2017, and the stratospheric temperature
was much higher than the most recent decadal average after
mid-August. This resulted in reduced formation of polar
stratospheric clouds (PSCs), which play an important role inozone destruction, and may have contributed the reduced
scale of the year’s ozone hole.
The ozone layer acts as a shield against ultraviolet radiation, which can cause skin cancer. The ozone hole first
appeared in the early 1980s and reached its maximum sizeof 29.6 million square kilometers in 2000. The Antarctic
ozone hole significantly affects the Southern Hemispheresurface climate in summer and is expected to continue toappear at least until the middle of this century according to
WMO/UNEP Scientific Assessment of Ozone Depletion:2014 Assessment for Decision-Makers. Close observationof the ozone layer on a global scale should remain a priority
for some time.
(Itaru Uesato, Ozone Layer Monitoring Center)

Figure 18 Characteristics of the Antarctic ozone hole
Upper left: Time-series representation of
the daily ozone-hole area for 2017 (redline) and the 2007–2016 average (blackline). The blue shading area represents
the range of daily minima and daily maxima over the past 10 years. Upper right:
Interannual variability in the annual maximum ozone-hole area. Bottom: Snapshots of total column ozone distribution on
the day of the annual maximum ozone holearea for the last three years; the ozone holeis shown in gray. These panels are basedon data from NASA satellite sensors of the
Ozone Monitoring Instrument (OMI).

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Unusual weather conditions in Japan during the first half of August 2017
 During the first half of August 2017, the Pacific side ofnorthern Japan experienced shorter-than-normal sunshine
durations and cooler-than-normal conditions, and the Pacific side of eastern Japan also experienced shorter-than-normal sunshine durations. These unseasonable
weather conditions were caused by the Okhotsk High persisting from the end of July and bringing cool and wet
northeasterly airflow to the Pacific side of northern andeastern Japan.
 During the same period, warmer-than-normal conditions
persisted in Okinawa/Amami in association with the North
Pacific Subtropical High shifting southward of its normal
position, corresponding to the Pacific-Japan (PJ) patternwith suppressed convective activity over the Philippines.
1. Climatic characteristics (Figure 19, Table 3)
In the first half of August 2017, cloudy and rainy conditions were prominent on the Pacific side of northern andeastern Japan. This led to below-normal sunshine durationsin these regions and below-normal temperatures, especiallyin northern Japan. During the period from 1 to 16 August,the ratio of the sunshine duration to the normal averaged
over the Pacific side of northern Japan was 42% (lowest
all-August figure since records began in 1946: 58%(1998)), representing a significant lack of sunshine in theregion. In addition, the mean temperature anomaly was-1.9°C (lowest all-August monthly mean temperature
anomaly since records began in 1946: -3.6°C (1980)).
Meanwhile, warmer-than-normal conditions persisted in
the area from western Japan to Okinawa/Amami during theperiod. The mean temperature averaged over Okina
wa/Amami was +1.5°C, resulting in significantly hot conditions in the region for this period (highest all-Augustmean temperature anomaly since records began in 1946:+1.2°C (1998)).
2. Characteristic atmospheric circulation causing Japan’s weather conditions (Figures 20 and 21)(1) Shorter-than-normal sunshine durations andcooler-than-normal conditions on the Pacific side ofnorthern Japan and shorter-than-normal sunshine durations on the Pacific side of eastern JapanThe Okhotsk High, which occasionally emerges for several

Figure 19 Mean temperature anomalies, precipitation ratios and sunshine duration ratios for the period from 1 to 16 August 2017
The base period for the normal is 1981 – 2010.
eral days near the surface over the Sea of Okhotsk (usuallyduring summer) has persisted since the end of July, bringing cool wet northeasterly flows to the Pacific side ofnorthern and eastern Japan. Typhoon Noru passed over andaround the islands of Japan in early August, after which
low-pressure systems passed repeatedly over mainland
Japan in association with the southward shift of the westerly jet from its normal position and a weaker-than-normal
northwestward extension of the North Pacific SubtropicalHigh (NPSH). These atmospheric circulations increased
the number of cloudy and rainy days on the Pacific side ofnorthern and eastern Japan.
The persistence of the Okhotsk High is presumed to bemainly due to blocking-high development over the Sea of
Okhotsk in association with the meandering westerly jet
stream over northern Eurasia.

Table 3 Regional averages of mean temperature anomalies and sunshine duration ratios for the period
from 1 to 16 August 2017

Sea of Japan side
Pacific side
Sea of Japan side
Eastern Japan
Pacific side
Sea of Japan side
Western Japan
Pacific side
Okinawa/Amami

Northern JapanTCC News

Mean temperature anomaly (oC)
-0.8
-1.9
+0.1
-0.2
+0.8
+0.8
+1.5

11

Sunshine duration ratio (%)
97
42
84
57
91
88
118

No. 50 | Autumn 2017

(2) Warmer-than-normal conditions in Okinawa/Amami
Throughout the first half of August, the NPSH did notextend to mainland Japan as usual and shifted southward
of its normal position, corresponding to the Pacific-Japan(PJ) pattern (Nitta 1987; Kosaka and Nakamura 2010) with
suppressed convective activity over and around the Philippines. This anomalous atmospheric circulation in the lower
troposphere caused longer-than-normal sunshine durations,adiabatic heating associated with stronger-than-normal
subsidence

subsidence and westerly warm air inflow, thereby contributing to significantly warm conditions in Okinawa/Amami.
The Tibetan High in the upper troposphere extended
southward to cover Okinawa/Amami. This is also presumed to be related to the warm conditions over the area.
This NPSH enhancement is considered to have beencaused by suppressed convective activity over and aroundthe Philippines, which is likely to be associated with theintraseasonal variability of the tropical atmosphere.

Figure 20 Primary factors contributing to the unseasonable weather conditions observed during thefirst half of August 2017
Solid lines show elements for 2017, and dashed lines
show the normal.

Figure 21 Primary factors contributing to the sustainment of the Okhotsk High and the strong expansion of the Pacific High to the south of Japan during
the first half of August 2017

TCC contributions to Regional Climate Outlook Forums
WMO Regional Climate Outlook Forums (RCOFs) bring
together national, regional and international climate experts
on an operational basis to produce regional climate outlooks
based on input from participating NMHSs, regional institutions, Regional Climate Centers and global producers ofclimate predictions. By providing a platform for countries
with similar climatological characteristics to discuss related
matters, these forums ensure consistency in terms of access to and interpretation of climate information.
In autumn 2017, TCC dispatched experts to SASCOF-11,
provided seasonal forecast materials to ASEANCOF-9 andNEACOF-13, and sent two expert representatives to a
WMO-coordinated Workshop on global review of RCOFs in
September.

the upcoming winter monsoon season (Oct. 2017 to Feb.
2018).
As part of the activities of WMO’s Global Producing
Centers for Long-range Forecast (GPC-LRFs), Takuya
Komori from GPC Tokyo provided a winter monsoon outlook based on JMA’s dynamical seasonal ensemble prediction system with probabilistic information on atmosphericvariability and the evolution of conditions in the tropical
Pacific and Indian Ocean for winter 2017/2018. The information was intended to support country-scale outlooks
from NMHSs in South Asia and a consensus outlook forSouth Asia.
At the forum, attendees discussed their experience ofusing climate information, with Mr. Komori contributing
to promote better use of climate services through future
SASCOF activities.

SASCOF
The Maldives Meteorological Department (MMD)
hosted the 11th winter session of the South Asian Climate
Outlook Forum (SASCOF-11) from 25 to 27 September
2017 in Malé, Maldives. The forum was supported by
WMO and the Regional Integrated Multi-hazard Early-warning System for Africa and Asia (RIMES) withfunding from the Government of Canada. More than 50
people attended the event to discuss climatic conditions forthe

TCC News

WMO Workshop on Global Review of RCOFs
The WMO Workshop on Global Review of RCOFs,
held from 5 to 7 September 2017 in Guayaquil, Ecuador,
provided a detailed review of current processes at various
RCOFs in order to highlight related gaps and provided aplatform for ideas toward more effective and sustainable
provision of climate products/services for decision-making.

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No. 50 | Autumn 2017

sion-making. More than 40 experts from international organizations involved in RCOF processes (including representatives from the Regional Climate Center (RCC),
GPC-LRF and the Lead Center for LRF Multi-Model Ensemble (LC-LRFMME)) attended, with two TCC experts
contributing to discussions on aspects of RCOF operations
from regional and global-center viewpoints.

The final report of the workshop is available on the meetingwebsite, and the event’s outcomes and recommendations
are expected to help organizations involved in RCOF operations to improve related implementation.
(SASCOF-11: Takuya Komori: Tokyo Climate Center,
WMO Workshop on Global Review of RCOFs:
Shoji Hirahara and Yasushi Mochizuki, Tokyo Climate
Center)

The Fifth Session of the East Asia winter Climate Outlook Forum(EASCOF-5)
The World Meteorological Organization (WMO) actively
supports the activities of the Regional Climate Outlook Forum (RCOF), which brings together experts from climatologically homogeneous regions and provides consensus-based seasonal predictions and information. As one of
the RCOFs, the East Asia Winter Climate Outlook Forum(EASCOF) was jointly established by the China Meteorological Administration (CMA), the Japan Meteorological
Agency (JMA), the Korea Meteorological Administration(KMA), and Mongolia's National Agency for Meteorology
and Environment Monitoring (NAMEM) in 2012.
The fifth session of EASCOF (EASCOF-5) was held at
JMA's headquarters in Tokyo, Japan, from 8 to 10 November 2017. More than 30 experts from China, Japan, Mongolia and the Republic of Korea attended the event, sharing
information on the current status of and future plans forseasonal forecasting services in individual National Meteorological and Hydrological Services (NMHSs). The attendees

tendees also discussed recent understandings of phenomena
related to seasonal prediction of the East Asian WinterMonsoon (EAWM) and seasonal outlooks for the coming
winter. A new session providing a platform for discussionof good practices toward user involvement in climate services was also held to encourage NMHS efforts in the promotion of climate service utilization. At the session, attendees from each NMHS talked about their current efforts
to promote the utilization of climate information in collaboration with specific sectors, including those of agriculture,energy and water resources. Invited speakers from the agricultural sector also gave presentations on how climate information had benefitted them, and the attendees engaged in
active discussions. Exchanges of knowledge in thisthree-day forum are expected to help develop attendees’
understanding of phenomena related to EAWM and support
improvement of their climate services.
Forum materials are available on the EASCOF portal.
(Atsushi Minami, Tokyo Climate Center)

Attendees with JMA Global Environment and Marine Department Director-General Shogo Tanaka

TCC News

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No. 50 | Autumn 2017

Update of website on RA II Information Sharing for Climate Services
Climate services today play increasingly important roles
in helping various socio-economic sectors to reduce related
negative impacts and adapt to climate change and global
warming. Against such a background, National Meteorological and Hydrological Services (NMHSs) need to provide high-quality, high-precision climate information inconsideration of accessibility and user needs, and engage invarious activities related to the Global Frameworks for
Climate Services (GFCS) initiative to promote utilization ofclimate information in user sectors.
For the improvement of climate services and the successful implementation of GFCS, it is important to share
information on the services, good practices and lessons
learned in climate-related activities, especially among
NMHSs in climatologically similar region. However, suchimportant information has not so far been fully shared
among NMHSs in WMO Regional Association II (RA II).
In

In response to related decisions taken at the 15th and 16th
sessions of RA II to improve information sharing on climate
services in the region, TCC operates a dedicated website at
http://ds.data.jma.go.jp/tcc/RaiiInfoshare/ (see TCC News
No.36 for more information).
A July 2017 questionnaire survey conducted by TCC to
support updating of the website generated responses from
more than 10 countries thanks to the kind cooperation of
persons involved. Based on the information provided, thesite was refined in October with additions including aclickable map to support usability and accessibility to individual NMHS’ information on climate services.
TCC is committed to supporting the improvement of RA
II climate services via the operation of the website.
(Atsushi Minami, Tokyo Climate Center)

You can also find the latest newsletter from Japan International Cooperation Agency (JICA).
JICA’s World (October 2017)https://www.jica.go.jp/english/publications/j-world/1710.html
JICA’s World is the quarterly magazine published by JICA. It introduces various cooperation projects and partners alongwith the featured theme. The latest issue features “Refugees and Displaced People Rebuilding the Lives of the Displaced”.
Tokyo Climate Center (TCC), Japan Meteorological Agency
Address: 1-3-4 Otemachi, Chiyoda-ku, Tokyo 100-8122, Japan
TCC Website: http://ds.data.jma.go.jp/tcc/tcc/index.html

Any comments or inquiry on this newsletter and/or the TCC
website would be much appreciated. Please e-mail to
tcc@met.kishou.go.jp.
(Editors: Kiyotoshi Takahashi, Yasushi Mochizuki
and Atsushi Minami)

TCC News

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No. 50 | Autumn 2017