October 2007

No. 10Contents
El Niño Outlook (October 2007 - April 2008)

1

JMA’s Seasonal Numerical Ensemble Prediction for 2007/2008 winter2

Cold Season Outlook for 2007/2008 winter in Japan

4

Summary of Asian Summer Monsoon 2007

5

“ClimatView”: Online Web-based Interactive Climate Database launched

7

TCC Staff Members attend a Training Course in Malaysia

8

Summary of UV Radiation for 2007 Summer Season in Japan

8

El Niño Outlook (October 2007 - April 2008)
The NINO.3 SST is likely to be below normal during theforecast period. It is likely that La Niña conditions will continue until spring 2008.

Subsurface negative temperature anomalies through thecentral and eastern parts and positive temperature anomalies in the western part were prominent (Figure 2). Convective activities were below normal around the date line
(Figure 1b). In the central equatorial Pacific, westerly wind
anomalies at the upper troposphere and easterly wind
anomalies at the lower troposphere were prominent. Thesefeatures are consistent with the oceanic and atmosphericconditions seen during La Niña events and indicate more
typical La Niña conditions than in August 2007.

In September 2007, the SST deviation from a sliding
30-year mean SST averaged over the NINO.3 region was-1.3˚C. The five-month running mean of the NINO.3 SST
deviation was -0.9˚C for July 2007. SSTs were below
normal throughout the central and eastern equatorial Pacific and above normal in the western part in September(Figure 1a).

Figure 1 Monthly mean conditions of the Pacific and Indian Ocean sectors in September 2007 for (a) sea surface
temperature (SST) anomalies and (b) outgoing long wave
radiation (OLR) anomalies
Contour intervals are 0.5˚C in (a) and 10W/m2 in (b). Baseperiods for normal are 1971-2000 in (a) and 1979-2004 in (b).

Tokyo Climate Center

Figure 2 Monthly mean depth-longitude cross sections of(a) temperature and (b) temperature anomalies in theequatorial Pacific for September 2007
Contour intervals are 1˚C in (a) and 0.5˚C in (b). Base period
for normal is 1987-2006.

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No. 10 | October 2007

Under the La Niña conditions mentioned above, thenegative SST anomalies in the eastern equatorial Pacifictend to be maintained by the ocean-atmosphere interaction.
The JMA's El Niño forecast model predicts that the
NINO.3 SST will be below normal during the forecast period (Figure 3).
Considering all the above, the NINO.3 SST is likely tobe below normal during the forecast period. It is likelythat La Niña conditions will continue until spring.
For details, please refer to El Niño Monitoring Page of
the TCC’s website: http://ds.data.jma.go.jp/tcc/tcc/
products/elnino/index.html(Ikuo Yoshikawa, Climate Prediction Division)

Figure 3 Outlook of the SST deviation for NINO.3 by
the El Niño forecast modelThis figure indicates a time series of the monthly SST deviation for NINO.3 (5°N-5°S, 150°W-90°W). Thick linewith closed circle shows the observed SST deviation andboxes show the predicted one for the next six months by the
El Niño forecast model. Each box denotes the range where
the SST deviation will be included with the probability of70%.

JMA’s Seasonal Numerical Ensemble Prediction for 2007/2008 winterIn 2007/2008 winter, an anomaly pattern in the central andeastern Pacific in the upper troposphere, which seems to berelated to the La Niña event, is predicted by JMA’s seasonal
numerical ensemble prediction system, while typical anomaly
pattern during La Niña events is not predicted in the western
Pacific. It might be related to the positive SST anomalies in
the Indian Ocean. It is noted that the skill of the SSTs andprecipitation in the Indian Ocean is not so high that the results should be interpreted with caution.
1. Introduction
In this report, JMA’s seasonal numerical ensemble prediction for 2007/2008 winter (DJF), which is used for oneof the prognostic tools for the JMA’s operational cold season outlook issued on 25 October 2007, is introduced. The
prediction consists of 51 ensemble members whose initialdates are 18 October 2007, and employs the two –tiermethod: first, global SSTs are predicted using
a combination of persisted anomalies, climatology and prediction with the JMA’s El Niño
prediction model (atmosphere-ocean coupledmodel; CGCM), and then the specific SSTs are
fed in an atmospheric model (AGCM). Details
on the prediction system and verification maps
based on 22-year hindcast experiments areavailable at http://ds.data.jma.go.jp/tcc/tcc/
products/model/index.html. This report is organized as follows. In section 2, the predicted
global SST anomalies are presented. Then, thepredicted circulation fields in the tropics andsub-tropics associated with those SST anoma-lies are described. Finally, the predicted circulation fields
in the middle and high latitudes in the Northern Hemisphere
are explained.
2. SST anomalies (Figure 4)
During 2007/2008 winter, the SSTs in the equatorial
Pacific are predicted to be slightly above normal in thewestern part and negative anomalies exceeding -0.5°C in
the central and eastern parts. Positive anomalies are also
seen in the South Pacific Convergence Zone (SPCZ). Thisanomaly pattern is similar to the one typically observed
during La Niña events. In the Indian Ocean, the SSTs are
predicted slightly above normal, except for the Bay of Bengal, where relatively negative anomalies are seen. Positive
SST anomalies are predicted in the Atlantic.

Figure 4 Predicted SST anomalies for 2007/2008 DJF

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No. 10 | October 2007

3. Circulation fields in the tropics and sub-tropics (Figure 5)
As expected from the predicted SST anomalies, below
normal precipitation is predicted in the equatorial central
and eastern Pacific. On the other hand, above normal precipitation is predicted in the western Pacific, SPCZ and theAtlantic. Though above normal precipitation is also seen in
the Indian Ocean, the hindcast indicates that the forecastingskills for the rainfall are generally so low in this area thatthe results should be interpreted with caution.
Consistent with the precipitation pattern, the upper tropospheric velocity potential anomalies are negative (moredivergent) over the Indian Ocean. Positive (more convergent) anomalies are predicted over the tropical western Pacific. It should be noted that the results of negative anomalies over the Indian Ocean should be interpreted with caution since the skills for the upper tropospheric velocity po-

tential from the hindcast are low like those for the rainfall.
In the upper troposphere, cyclonic circulation anomalies
are located on north and south sides of the central and eastern Pacific and anti-cyclonic circulation anomalies are located poleward of each cyclonic anomaly, which is often
seen during La Niña events. In the lower troposphere, thatkind of typical pattern during La Niña events is obscure,though it is seen in the upper troposphere. The anticyclonic pattern in the northern central and eastern Pacificin extratropics is also seen in the lower troposphere. On theother hand, in the western Pacific, typical anomaly pattern
is not seen in both upper and lower troposphere. It might
be related to the positive SST anomalies in the Indian
Ocean.

(a)

(b)

(c)

(d)
Figure 5 Predicted atmospheric fields of 2007/2008 DJF (Ensemble mean of 51 members)(a) Precipitation (contour) and anomaly (shading). Contour interval is 2 mm/day.
(b) Velocity potential at 200 hPa (contour) and anomaly (shading). Contour interval is 2x106m2/s.
(c) Stream function at 200 hPa (contour) and anomaly (shading). Contour interval is 16x106m2/s.
(d) Stream function at 200 hPa (contour) and anomaly (shading). Contour interval is 5x106m2/s.

4. Circulation fields in the middle and high latitudes in
the Northern Hemisphere (Figures 6 and 7)
The ensemble prediction says that the winter mean 500hPa height anomalies will be above normal over most parts of
the Northern Hemisphere, except for the high latitudes suchas northern part of North America and Europe. Relatively
large positive anomaly is seen over the northeastern Pacific,
which is often seen during La Niña events. The probabilistic
distribution of EOF1 score of the 500hPa height anomalies in
DJF predicted by each member is positively biased, whilethat of EOF2 is near normal. EOF1 score is used as the AO
index and the AO is the leading mode of the low frequency
variability of the atmosphere in the Northern Hemisphere.
The EOF1 scores biased positively in this case, however, weneed more consideration to conclude that the probability ofpositive AO situation would be seen, since EOF1 scores lookaffected by the positive anomalies in the northeastern Pacific,
while the center of variability for EOF1 derived from analysis
is in the north Atlantic.

Figure 6 Predicted 500hPa height in the Northern Hemisphere for 2007/2008 DJF (Ensemble mean of 51 members)
Contour interval is 60 m. Anomalies are shaded.

(Akihiko Shimpo, Climate Prediction Division)

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No. 10 | October 2007

(c)

(b)

(a)

(d)

Figure 7 Histogram of predicted (2007/2008 DJF) (a) EOF1 and (b) EOF2 scores defined by the (c) first and (d) second EOFs
of 500hPa height anomalies in the Northern Hemisphere

Cold Season Outlook for 2007/2008 winter in JapanFor winter mean temperatures, near-normal temperatures
are expected with a 40% probability and both above-normal
and below-normal with 30% probabilities for Northern, Eastern and Western Japan. Both near-normal and warmer-thannormal temperatures with 40% probabilities are predicted for
Okinawa and Amami. Snowfall amounts are predicted to benear-normal with 40% probabilities on the Sea of Japan side.
However, we have not yet had enough signals for the coming
winter climate in Japan, so it is necessary to keep watching
the precursor signal carefully such as the significant shift of
the Arctic Oscillation phase.

3. Ensemble Prediction System (EPS)The Sea Surface Temperature Anomalies (SSTA) fed tothe atmospheric global model are positive in the tropicalwestern Pacific, slightly positive in the Indian Ocean andsignificantly negative along the equator in the central andeastern Pacific. Reflecting this SSTA distribution, precipitation anomalies are generally positive over the tropicalwestern Pacific and the Indian Ocean, especially to thenorth of New Guinea. This feature is almost the same as
the statistical feature which tends to appear during La Niña
event and the pattern of 500hPa height anomalies from theeastern Pacific to North America is also consistent with it.
Meanwhile, the EPS seems to have no signal of the Eurasian teleconnection pattern and the Arctic Oscillation (AO)
pattern. As the result, the pattern of 500hPa anomalies
around Japan is dissimilar to the statistical feature which isoften observed during La Niña events and there is only asignal of warming trend of tropospheric temperatures.
From these points of view, it is considered that there is aweak signal of normal or slightly warm winter for Northernand Eastern Japan.

1. Long-term trends
The 11-month running mean temperatures over Japan
have been almost above normal since 1980’s. They havefluctuated with a period of 3 or 4 years in the positive
anomaly base and they are currently at one of the highest
peaks. Recently, winter mean temperatures have not been
below normal except for Northern Japan. The appearance
ratios (below normal: normal: above normal) for wintermean temperatures in recent 10 years are 1:3:6 for EasternJapan, 1:5:4 for Western Japan, and 0:2:8 for Okinawa andAmami. The tropospheric thickness temperature averaged
over the mid-latitudes of the Northern Hemisphere (30-50°N) also tends to be above normal since 1998 and it is likely
to be above normal in this winter. From these points ofview, it is considered that there is a signal of warm or normal winter for Eastern Japan, Western Japan, and Okinawa
and Amami, and no signal for Northern Japan.

Conclusion
Considering the above points, a signal of warm winterand a signal of cold winter cancel each other, so the base of
winter mean temperature is predicted to be near normal andthe winter monsoon which brings heavy snow on the Sea ofJapan side is also predicted to be near normal. More to thepoint, the warm effect by the long-term trends and the cold
effect by the La Niña event are balanced. Taking into account that the AO which is closely connected with winterclimate in Japan is not predicted as a significant signal,
probability of warm or cold winter is expected to be small.
Nonetheless, we should carefully keep monitoring thesituation of the Arctic Oscillation because the active convection around the Maritime Continent affected by the La
Niña event will work synergistically in increasing the possibility of major cold waves if the Arctic Oscillation becomes a certain level of negative phase.

2. Oceanic condition
The La Niña event which occurred in last spring has
developed to a mature phase in this autumn and it is predicted to continue during the coming winter. According toour statistical studies, anti-cyclonic and cyclonic circulation
anomalies tend to be dominant over the southern part ofChina and around Japan, respectively, during La Niña
events. This feature is explained by the theory of Rossby
wave enhanced by the active convection around the Maritime Continent and the eastward propagation of quasistationary Rossby wave packet. Our statistical study also
shows that cold or normal winters tend to be observed inmost parts of Japan during La Niña events. From thesepoints of view, it is considered that there is a signal of cold
or normal winter for Northern, Eastern and Western Japan.

Tokyo Climate Center(Norihisa Fujikawa, Climate Prediction Division)4

No. 10 | October 2007

Summary of Asian Summer Monsoon 2007
1. Monsoon activities (Figure 8)
Asian summer monsoon activities inferred from the seasonal mean OLR (Outgoing Longwave Radiation) overSoutheast Asia and India from June to September (hereafter
called “the monsoon period”) were enhanced in the Arabian
Sea and near Indonesia, and suppressed near Japan. The
most active convection area of the Asian monsoon shifted
westward from its normal position. In June, convective
activities in the Arabian Sea were extremely enhanced,
whereas they were suppressed in the Bay of Bengal. In
June and July, convective activities were suppressed inSoutheast Asia except in Indonesia. In September, convective activities in the Asian monsoon region were extremely

enhanced.
According to the India Meteorological Department(IMD), the southwest monsoon precipitation over India
during the monsoon period was more than its normal. The
onsets of the monsoon were later than normal in southeast
India and earlier than normal in northwest India, respectively.
The total precipitation during the Bai-u season 2007 wasmore than normal in the Pacific side of Western and Eastern Japan especially in July, while less than normal in
Northern Japan. Both the beginnings and the ends of theBai-u season were later than normal in most districts inJapan.

Figure 8 Four-month mean OLR (Outgoing Longwave Radiation) (left) and its anomalies (right) (June-September 2007)
Solid lines indicate OLR (W/m2) with a contour interval of 20W/m2, and color shadings indicate OLR anomalies (right).

2. Precipitation and temperature
During the monsoon season (June-September), the fourmonth total precipitation amounts, based on CLIMAT reports, were above normal from southern India to Pakistan,Kalimantan Island to western New Guinea, around the Yellow Sea, while below normal in northern India, Mongolia tonorthern China (Figure 9). In June, precipitation amounts
were extremely heavy from Pakistan to western India corresponding to enhanced convective activities in the ArabianSea. In July, extremely heavy precipitation amounts wereobserved in central Southeastern Asia, while extremely
light precipitation amounts were observed around southern
China. In August, precipitation amounts were extremely
heavy around the Yellow Sea and the Eastern China Sea

due to warm/wet flow and tropical storms. From July to
September, precipitation amounts were extremely lightaround Mongolia. During the same period, the four-monthmean temperatures were higher than normal over most of
Asia especially from Mongolia to northern China, while
they were slightly lower in some parts of southern China(Figure 10). In June, temperatures were extremely highfrom Northern Japan to northern China. In July, extremely
high temperatures were observed around southern China.
In August, temperatures were extremely high from southwestern China to northern India. In September, temperatures were extremely high in Japan. From July to September, extremely high temperatures were observed around
Mongolia.

Figure 9 Four-month precipitation ratio (%), and tropical cyclone tracks in the northwestern Pacific, from Juneto September 2007

Figure 10 Four-month mean temperature anomaly(℃) from June to September 2007

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No. 10 | October 2007

3. Tropical Cyclones
During the monsoon season, 12 tropical cyclones oftropical storm (TS) intensity or higher formed over thewestern North Pacific, and the number of the occurrence
was lower than the 1971-2000 average of 16.4 (Figure 9).
There were 11 tropical cyclones which approached or madelandfall on East and Southeast Asia (Table 1). The typhoon“Man-Yi” which hit Japan in the middle of July led to five
deaths (Japan Fire and Disaster Management Agency). In
the beginning of August, the typhoon “Pabuk” and thetropical storm “Wutip” caused 12 fatalities in the Philippines. After being downgraded to a tropical depression, the“Pabuk” caused damage in the Korean Peninsula. In the
middle of August, the typhoon “Sepat” caused more than
50 deaths in China and the Philippines. In the middle ofSeptember, the typhoon “Wipha” caused 7 fatalities in
China (Ministry of Civil Affairs of the People’s Republic ofChina).
Cyclone “Yemyin” hit Pakistan in the end of June andcaused more than 200 deaths.

The number of fatalities is based on the Emergency Disasters Database (EM-DAT) except for specified one.
4. Noticeable weather-related disasters other than tropical cyclones
Major weather disasters in Asia, except for those related
to tropical cyclones during the monsoon season are the following.
In India, floods caused over 1300 fatalities in total. Also
floods occurred in the end of July or beginning of August in
Pakistan, Bangladesh, and Nepal, which led to more than200, 800, 170 deaths, respectively.
In addition, floods led to more than 700 fatalities in
China in total. Around Sulawesi Island in Indonesia, over
100 were killed due to floods in the beginning of August.
In August and September, drought conditions were reported
in northern China (Beijing Climate Center).

Table 1 Tropical cyclones which approached/made landfall on East and Southeast Asia from June to September 2007
Information is issued by RSMC Tokyo-Typhoon Center, except for “Affected Countries”.

ID
Number

Name

Date
(UTC)

Category1)

Minimum
Pressure2)(hPa)

MaximumWinds3)(Knots)Affected Countries

T0703

Toraji

7/5

TS

996

35

China

T0704

Man-Yi

7/8 - 7/16

TY

930

95

Japan

T0705

Usagi

7/29 - 8/4

TY

945

90

Japan

T0706

Pabuk

8/5 - 8/9

TY

975

65

China

T0707

Wutip

8/8 - 8/9

TS

990

40

China

T0708

Sepat

8/12 - 8/19

TY

910

110

China

T0709

Fitow

8/29 - 9/8

TY

965

65

Japan

T0711

Nari

9/13 - 9/16

TY

940

100

Japan, Korea

T0712

Wipha

9/16 - 9/19

TY

930

100

China

T0713

Francisco9/23 - 9/25

TS

990

45

China

T0714

Lekima9/30 - 10/4

STS

975

60

Vietnam1) Intensity classification of tropical cyclones
TS: Tropical Storm, STS: Severe Tropical Storm, TY: Typhoon2) Estimated minimum central pressure3) Estimated maximum 10-minute mean winds

Tokyo Climate Center

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No. 10 | October 2007

5. Atmospheric circulation and convection (Figure 11)
In June, convective activities in the Arabian Sea were
extremely enhanced coincident with the arrival of the active
phase of the Madden Julian Oscillation (MJO), and they
were suppressed in the Bay of Bengal and Southeast Asia
except in Indonesia. Associated with these convective
anomalies, the Tibetan High in the upper troposphere
shifted westward from its normal position. In the lower
troposphere, the southwest monsoon in the Bay of Bengal
and Southeast Asia were weaker than normal. Meanwhile,in the western India and Pakistan, enhanced northward water vapor flux and its convergence were observed and theseareas had extremely heavy precipitation.
The eastward propagation of the active phase of MJO
was observed clearly in June and July. In early August, theactive convection area moved northward from near Indonesia to the north of the Philippines. In the lower troposphere,
cyclonic circulation anomalies in South China and anticyclonic circulation anomalies near Japan were observed.
The circulation anomaly pattern like this is called PacificJapan pattern (PJ pattern, Nitta 1987).
Asian summer monsoon was still very active in September. Convective activities were remarkably enhanced in the
Asian monsoon region as a whole. The southwest monsoon
precipitation in India was heavier than normal coincident
with the enhancement of the monsoon circulation in earlyand late September.

Figure 11 OLR anomalies and water vapor flux anomalies inJune 2007
Color shadings indicate OLR anomalies (W/m2) with a contour
interval of 10W/m2, and vectors indicate water vapor flux anomalies at the 925-hPa level.

(1 and 5 Atsushi Goto, 2 – 4 Yoshikazu Fukuda,
Climate Prediction Division)
Reference:
Nitta, T., 1987: Convective activities in the tropical western
Pacific and their impact on the Northern Hemisphere summer circulation. J. Meteor. Soc. Japan. 65, 373-390.

“ClimatView”: Online Web-based Interactive Climate Database launched
JMA/TCC launched a web-based interactive climate
database “ClimatView”, a new service that provides
monthly climate data of the world, at http://
ds.data.jma.go.jp/gmd/tcc/climatview/. ClimatView enables users to view or download monthly mean temperatureand monthly total precipitation derived from CLIMAT reports which have been received and monitored by two
GCOS Surface Network Monitoring Centers, JMA and theDeutscher Wetterdienst (DWD), since 1982 and 1999, respectively.

By using "ClimatView", users can see and get monthly
mean temperature, monthly total precipitation and its anomaly or ratio at all available stations. Monthly means ofdaily maximum/minimum temperatures are also available.
These data are derived from CLIMAT messages via the
GTS line from the WMO Members in the world. This website is expected to help not only all NMHSs but also otherinstitutions and individuals in monitoring and analysis ofsurface climate and its variations for specific observation
stations as well as the globe.

Sample images of ClimatView

Tokyo Climate Center

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No. 10 | October 2007

TCC staff members attend a Training Course in Malaysia
TCC hopes that this Training Course will help MMD
A Training Course on Interpretation of Climate Products
and Climate Downscaling, organized by the Malaysian Me- further improve its seasonal forecasting services.
teorological Department (MMD) and the Ministry of Sci(Ryuji Yamada, Climate Prediction Division)
ence, Technology and Innovation Malaysia (MOSTI), washeld at the Headquarters of MMD at Petaling Jaya, Malaysia, from 22 to 26 October 2007. The Training Course wasattended by about 35 staff members of MMD including
those from regional offices. At the kind invitation of
MMD, Ms. Kumi Hayashi, Head of the Tokyo Climate
Center (TCC), and Mr. Ryuji Yamada, Scientific Officer of
TCC, attended the Training Course as trainers.
In the five-day Training Course, the trainers made lectures on the following topics:- JMA’s Numerical/Seasonal Prediction Models- Ensemble Prediction System and Making Guidance- Statistical Downscaling (lectured by Mr. Okura, Fujitsu
FIP Corporation)- Access to GPV data and its application using R Language- Re-analysis data (JRA-25) and its application- Usage of Analysis/Forecast Products ….

Summary of UV Radiation for 2007 Summer Season in JapanJMA has been conducting UV radiation observation at
three domestic stations, i.e. at Tsukuba (36º03´N, 140º08´E,
31.0m) since 1990, Sapporo (43º04´N, 141º20´E, 26.3m)
and Naha (26º12´N, 127º41´E, 27.5m) since 1991 within
the framework of WMO/GAW Programme. Figure 12
shows the monthly mean values of erythemal UV*1 daily
accumulation at the stations in 2007. At Sapporo, the highest monthly mean values were observed in two consecutive
months of June and July for these months. At Tsukuba, thevalues for June and August were the second highest, whileat Naha, the value for August was the second lowest.
Figure 13 shows the monthly mean anomalies of daily
maximum estimated UV Index*2 for August 2007. The
values more than 110% of the 1997-2006 average were
dominant in the Pacific side of Hokkaido to Kanto region.
On the other hand, the values less than 90% of the average
were dominant in the Nansei Islands. We can see a contrastive pattern especially between Kanto region and the Nansei
Islands. This contrast is mainly the reflection of the con-trast of sunshine duration between the above two regions,i.e. much sunshine duration in Kanto region where the subtropical high prevailed and less sunshine duration in the
Nansei Islands where tropical cyclones/depressions often
passed. Additionally, large ozone amount over the Nansei
Islands (second highest total ozone in record for August atNaha) is thought to be another reason for the lower UVIndex there.
*1 Erythemal UV is widely used as a scale of UV radiation that shows the degree of effect on the human body,
calculated by considering different levels of influence depending on the wavelength.
*2 UV Index is a standardized index of erythemal UV, andin Japan, the value observed usually ranges from 0 to 12.
JMA’s UV Index daily forecast can be referred to at thefollowing website: http://www.jma.go.jp/en/uv/.
(Hiroshi Ishihara, Ozone Layer Monitoring Office)Figure 12 Monthly mean values of erythemal UV daily accumulation
at Sapporo, Tsukuba and Naha
Closed circles indicate monthly mean values. The solid lines represent thenormal (i.e. the average over 1990-2006 for Tsukuba and 1991-2006 forthe other stations) with bars of standard deviation.

Figure 13 Monthly mean anomalies of daily maximum estimated UV Index for August 2007

Any comments or inquiries on this newsletter and/or the Tokyo Climate Center (TCC), Climate Prediction Division, JMA
TCC website would be much appreciated. Please e-mail Address: 1-3-4 Otemachi, Chiyoda-ku, Tokyo 100-8122, Japan
to: tcc@climar.kishou.go.jp
TCC website: http://ds.data.jma.go.jp/tcc/tcc/index.html(Chief Editor: Kumi Hayashi)Tokyo Climate Center

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No. 10 | October 2007