1. Seasonal Outlook for summer 2013 over Japan
Tadayuki Okubo
(Forecaster)
Tokyo Climate Center,
Japan Meteorological Agency (JMA)
Good afternoon, everyone.
I am Tadayuki Okubo of Japan Meteorological agency.
I’m very happy to give a presentation.
Today, I’d like to talk about seasonal outlook for summer 2013 over Japan.

2. Outline Warm Season Forecasts in Japan Oceanic Condition and Outlook
Atmospheric Circulation Outlook
Summary
I’d like to speak in the following order.
First, Warm　Season Forecasts in Japan
Secondly, Oceanic Condition and Outlook
Next, Atmospheric Circulation Outlook,
and Summary at the end.

3. Warm Season Forecasts in Japan
--- Summer (June July August )
First of all, I’d like to show you Warm Season Forecasts in Japan
Summer　June July August 2013.

4. Probability of seasonal mean temperature for summer ( June – August ) 2013
Climatology 33
済：図
未：ノート
Northern Japan
Normal
Low
High 20 40
Eastern Japan
Western Japan 20 40 20 40
The following is warm seasonal forecasts, which was issued on February 25th.
We use a probabilistic seasonal forecast.
This is the probability forecasts of mean temperature in summer.
Summer mean temperatures are expected to be both near normal and above normal with 40% probabilities in northern, eastern and western Japan.
Okinawa/Amami has no particular features.
Okinawa/Amami (Southern Japan) 30 40 4

5. Probability of seasonal mean precipitation for summer ( June – August ) 2013
Climatology 33
Above normal
Normal
Below normal
済：図
未：ノート
Northern Japan 40 30
Western Japan
Eastern Japan 40 30 30 40
This is the probability forecasts of precipitation amounts for summer.
Summer precipitation amounts are expected to be both near normal and above normal with 40% probabilities in Okinawa/Amami.
Northern, Eastern and Western Japan have no particular features.
These forecasts were prepared in accordance with the JMA's coupled global circulation model.
Okinawa/Amami (Southern Japan) 20 40 5

6. Oceanic Condition and Outlook
Let me now turn to the Oceanic Condition and Outlook.

7. Oceanic Condition and Outlook (1) Current Condition in February 2013
済：図（２月版）
未：ノート
Upper figure shows monthly mean sea surface temperature anomalies in February 2013.
We can see the negative anomalies from the central to eastern equatorial Pacific, and positive in the western part.
Lower figure shows Depth-longitude cross sections of monthly mean temperature anomalies along the equator in the Indian ocean and Pacific ocean in February 2013.
We can see the negative anomalies in the eastern Pacific.
On the other hand, we can see the positive anomalies from the western to central Pacific.
These oceanic conditions were similar to those observed during the past La Niña events, but deviations from normal were small.
upper : Monthly mean SST Anomalies (Feb. 2013)
lower : Depth-longitude cross sections of monthly mean temperature anomalies(Feb. 2013) 7

8. Oceanic Condition and Outlook (2) NINO.3 SST forecast
済：図（２月版）
未：ノート
JJA
El Niño Outlook
ENSO neutral conditions are likely to continue during the northern hemisphere summer 2013.
This figure shows a time series of SST deviation in NINO.3.
Red line denotes observed SST deviations and each yellow box denotes the forecasted range where the SST deviation will be included with the probability of 70%.
As you can see, the JMA's coupled global circulation model predicts that the NINO.3 SST will be below normal into the northern hemisphere spring,
and become near normal thereafter.
Therefore, ENSO neutral conditions are likely to continue during the summer.
Monthly SST deviation in NINO.3

9. Atmospheric Circulation Outlook
Next, I'd like to describe the atmospheric circulation outlook that has been forecast by JMA's coupled global circulation model prediction.

10. Numerical Prediction (1) SST & Precipitation anomaly JJA
NINO.3
above normal
below normal
These figures show the ensemble mean prediction for summer.
Upper figure shows sea surface temperature anomalies.
The NINO.3 SST will be almost near normal during the summer.
The SST anomalies in the tropical Indian Ocean were expected to be below normal.
And Western Pacific was expected to be slightly above normal.
Lower figure shows precipitation anomalies for summer.
Precipitation anomalies are expected in response to sea surface temperature.
We can see below normal rainfall in the equatorial Indian Ocean.
below normal

11. Numerical Prediction (2) Precipitation anomaly JJA
above normal
I’d like to focus on around the Indian Ocean.
In summer, precipitation anomalies are predicted to be below normal in the equatorial Indian Ocean.
On the other hand, they are predicted to be above normal from the Bay of Bengal to the east of the Philippines.
below normal

12. Numerical Prediction (3) wind anomaly(vectors) and
stream function anomaly (color) 850hPa JJA
cyclonic rotation
Matsuno-Gill response (cold source)
This figure shows wind anomaly and stream function anomaly at 850hPa for summer.
In response to below normal rainfall in the Indian Ocean, and westerly wind anomalies in the lower troposphere are predicted from the equatorial Indian Ocean to Indonesia.
These are considered to correspond to Matsuno Gill response of cold source.
In response to their westerly anomalies, throughout the summer season, a strong cyclonic anomalies are from the Bay of Bengal to the East of the Philippines.

13. Numerical Prediction (4) stream function and anomaly (200hPa) JJA
Tibetan high is strong
This figure shows the stream function at 200 hPa for summer.
Corresponding to active convections from the Bay of Bengal to the Philippines, the Tibetan high will receive a supply of latent heat.
The Tibetan high is predicted to be stronger than normal, and the subtropical jet, which flows along the northern edge of the Tibetan high, is likely to shift northward from its normal position.

14. Numerical Prediction (5) 500hPa height and Sea Level Pressure anomaly JJA
Left figure shows the 500hPa height and anomaly for summer.
500hPa height anomalies are predicted to be positive over mid and high-latitudes of the Northern Hemisphere.
Right figure shows Sea Level Pressure and anomaly for summer.
As the characteristics of the atmospheric circulation around Japan, the North Pacific high is likely to shift northward from its normal position.
Northern, eastern and western Japan are expected to experience above normal or near normal temperatures covered by the North Pacific high.
On the other hand, Okinawa/Amami is expected to be influenced by moist southerly flow more frequently than normal.
500hPa height anomalies are predicted to be positive over mid and high-latitudes Northern Hemisphere.
The North Pacific high is likely to shift northward from its normal position. Okinawa/Amami is expected to be influenced by moist southerly flow more frequently than normal.

15. Numerical Prediction (6) Tropospheric thickness temperature
（℃）
This figure shows the tropospheric thickness temperature averaged over the mid-latitudes of the Northern Hemisphere (30ﾟN to 50ﾟN),
which is correlated with temperatures over Japan, is predicted to be slightly above normal in this summer.
(year)
CGCM (30 year, Hindcast)
anomaly correlation
Valid period
JJA
Initial month
Feb.
tropospheric thickness
( hPa) 30ﾟN – 50ﾟN
0.64
　The tropospheric thickness temperature averaged over the mid-latitudes of the Northern Hemisphere (30ﾟN – 50ﾟN), which is predicted to be slightly above normal.

16. Summary（Conceptual diagram）② ③
Tibetan high ①
North Pacific high ④
① The SST in IOBW will be below normal, the SST in NINO.WEST will be slightly above normal during the summer.
② Three-month precipitation anomalies are predicted to be above normal from the Bay of Bengal to the east of the Philippines.
③ The Tibetan high is predicted to be stronger than normal, and the subtropical jet is likely to shift northward from its normal position
④ From②and③The North Pacific high is likely to shift northward from its normal position.
※ The tropospheric thickness temperature averaged over the mid-latitudes of the Northern Hemisphere (30ﾟN – 50ﾟN), which is predicted to be slightly above normal.
Summary
(1) The SST in tropical Indian ocean will be below normal, the SST in Western Pacific will be slightly above normal during the summer.
(2) Three-month precipitation anomalies are predicted to be above normal from the Bay of Bengal to the east of the Philippines.
(3) The Tibetan high is predicted to be stronger than normal, and the subtropical jet is likely to shift northward from its normal position
(4) From(2)and(3)The North Pacific high is likely to shift northward from its normal position.
In addition the tropospheric thickness temperature averaged over the mid-latitudes of the Northern Hemisphere is predicted to be slightly above normal.

17. Thank you. Temperature Category － ＋ Northern Japan 20 40 Eastern Japan＋
Northern Japan 20 40
Eastern Japan
Western Japan
Okinawa　and Amami 30
JMA's mascot is named Harerun (in the hope of hare, the Japanese word for “fine weather”), and is designed with elements of sun, cloud and rainfall. Harerun holds a green baton in prayer for a disaster-free, peaceful world.
Precipitation
Category － ＋
Northern Japan 40 30
Eastern Japan
Western Japan
Okinawa　and Amami 20
I’ve come to the end of the presentation, so thank you very much for listening.
(Category －: below normal, 0 : normal, + : above normal, Unit : %)

18. JJA Potential velocity and anomaly (200hPa) Precipitation anomaly
3-month average
Precipitation anomaly
SST anomaly

19. JJA Stream function (200hPa) Stream function (850hPa)
3-month average
Stream function (850hPa)
Precipitation anomaly

20. JJA 500 hPa height 200hPa Zonal wind 850hPa Temperature S.L.P
3-month average
850hPa Temperature
S.L.P

21. JMA seasonal forecast SLP & Surface temperature
initial date: February 2013
Ensemble-mean SLP anomalies JJA 2013
The Monsoon Trough would be strong.
Ensemble-mean Surface Temp. anomalies JJA 2013
The slightly below-normal temperature are predicted around the Philippines.
Proceeding to SLP and surface temperature fields,
corresponding to the enhanced convective activity around the Philippines, you can see the PJ pattern.
Consequently, the monsoon trough would be strong and the North Pacific High would extend to Japan.
And also the slightly below-normal surface temperature are predicted around the Philippines.
Q & A
Why do you use the zonal mean thickness for the seasonal products ?
Because we use it to estimate the affect of the ENSO and global warming.

22. Outline of the EPS for seasonal forecast
CGCM: JMA/MRI-CGCM
AGCM: JMA-GSM based on JMA/MRI unified model
TL95: deg　~　180km
L40: model top = 0.4hPa
Land: SiB
Sea ice: climatology
Initial condition: JRA-25/JCDAS
Initial perturbation: BGM (TRO, NH)
CGCM: MRI.COM
1.0deg in lon. X deg in lat.
75N-75S, 0-360E
L50
Initial condition: MOVE/MRI-COM-G
Initial perturbation: driven with BGM (TRO) of AGCM
We introduced CGCM (an atmosphere-ocean coupled global circulation model) in the last February as mentioned in this morning.
(The atmospheric part of CGCM is basically a low-resolution version of the AGCM for short-range forecast.
The oceanic part of CGCM has been developed at the Meteorological Research Institute.
Initial conditions for atmosphere are obtained from the result of analysis by JMA climate data assimilation system.
Those of ocean are obtained from the global ocean data assimilation system.
The Ensemble method use a combination of the initial perturbation method and the Lagged Average Forecasting method.
Nine members are run every five days, and the EPS consist of 51 members for the latest six initial dates. )
ENSEMBLE: BGM&LAF
Combination of BGM and LAF
9 members for each initial date
Size: 51 ( ENSO forecast: 30 )
Once a month

23. 100 hPa Height and Anomalies and Global Average Surface Temperature in Summer
100hPa Height Forecast and Anomalies
JJA
Global Average Temperature in June – August
The left figure shows the predicted 100 hPa height anomalies.
100 hPa height anomalies are predicted to be positive over the mid-high latitude in Northern Hemisphere.
Futhermore, in these ten years, above normal temperature tend to appear in all regions.
These tendencies indicate that this summer-averaged temperature tends to be above normal in Japan.
Anomalies are deviations from baseline( Average).
The black thin line indicates surface temperature anomaly of each year.
The blue line indicates their 5-year running mean.
The redline indicates the long-term linear trend.
100hPa height anomalies are predicted to be positive over the mid-high latitude in Northern Hemisphere. Furthermore, in these ten years, above normal temperature tend to appear in all regions. These tendencies indicate that this summer-averaged temperature tends to be above normal in Japan. 23

24. wind anomaly(vectors) and stream function anomaly (color) 850hPa JJA
left : 850hPa wind anomaly and stream function anomaly JJA.
light : 850hPa wind and stream function anomaly JJA.
wind anomaly(vectors) and
stream function anomaly (color) 850hPa JJA
Wind (vectors) and　stream function anomaly (color) 850hPa JJA

25. Numerical Prediction wind anomaly(vectors) and stream function anomaly (color) 850hPa　(June)
Anti-Cyclonic circulation
anomalies around Philippines.
Cyclonic circulation
anomalies around Philippines.
Westerly Wind anomalies
The summer climate over East Asia is well known to be deep relation with the convective activity around the Philippines through the propagation of the Rossby wave.
It is a kind of teleconnection and it is called PJ pattern.
850hPa Wind and Stream Function Anomalies (June 2013) 25

26. Numerical Prediction wind anomaly(vectors) and stream function anomaly (color) 850hPa(Juｌｙ)
Cyclonic circulation
anomalies around Philippines.
Westerly Wind anomalies
The summer climate over East Asia is well known to be deep relation with the convective activity around the Philippines through the propagation of the Rossby wave.
It is a kind of teleconnection and it is called PJ pattern.
850hPa Wind and Stream Function Anomalies (Juｌｙ 2013) 26

27. Numerical Prediction wind anomaly(vectors) and stream function anomaly (color) 850hPa (August)
Cyclonic circulation
anomalies around Philippines.
Westerly Wind anomalies
The summer climate over East Asia is well known to be deep relation with the convective activity around the Philippines through the propagation of the Rossby wave.
It is a kind of teleconnection and it is called PJ pattern.
850hPa Wind and Stream Function Anomalies (August 2013) 27

28. Pacific-Japan pattern
Precipitation Ratio (CLIMAT)
Contour: SLP
Shade: OLR anomaly
July 1993
July 1994
（Nitta, 1987）
The summer climate over East Asia is well known to be deep relation with the convective activity around the Philippines through the propagation of the Rossby wave.
It is a kind of teleconnection and it is called PJ pattern.
The upper figure shows SLP and OLR anomalies in 1993 when a extremely cool and wet summer hit Japan.
The shade color indicates OLR anomalies and the contour shows SLP.
As you can see, the convective activity around the Philippines was suppressed.
The CLIMAT data also shows below-normal precipitation in the northern part of the Philippines.
Consequently, the remarkable cyclonic circulation were established around Japan and
we had large amount of precipitation.
On the other hand, the lower figure also shows SLP and OLR anomalies in 1994 when a extremely hot and dry summer hit Japan.
Clearly, the westward extension of the North Pacific High was strong, corresponding to the enhanced convective activity around the Philippines.
Consequently, the CLIAMT data showed that the Philippines had large amount of precipitation in July 1994.
We can see the PJ pattern in the both years.
Well, generally speaking, a cool summer brings a poor harvest of rice which is a staple food in Japan.
That can also become a social issue.
Therefore, the PJ pattern is a major factor for predicting the summer climate over Japan and East Asia.
Below-Normal
Above-Normal
The summer climate of East Asia is known to be deep relation with the convective activity around the Philippines through the propagation of the Rossby wave. 28 28

29. 850hPa Stream Function and Anomalies JJA and Extension of the North Pacific High
Nitta (1987)
PJ pattern
850hPa Stream Function and Anomalies JJA 2013
Weak monsoon
The figure shows stream function and anomalies in the lower troposphere.
We can see anti-cyclonic circulation anomalies around Philippines.
It is likely to be associated with the negative precipitation anomalies in the region.
The climate of east Asia are known to be deep relation with the convective activity around Philippines through the propagation of the Rossby wave.
(It is called PJ pattern.)
The bottom figure shows composites of the anomalous stream function field for the weak monsoon years.
It is defined using OLR around Philippines ( 1980,1983,1993,1996,1998,2007 )
The anti-cyclonic circulation around Philippines is similar to the composite map.
So we consider that a hot summer will hit the southern Japan same as all of past weak monsoon years.
(On the other hand, the cyclonic circulation around northern Japan in the composite fields
is indistinct in the prediction fields.
I guess that it is because the prediction accuracy is not high in extra-tropical region. )
Composites of 850hPa Stream Function fields for weak monsoon years.
(1980,1983,1993,1996,1998,2007)
Hot summer hit southern Japan in all of those years.
Data Source: JRA-25 29

30. Oceanic Condition and Outlook NINO3 SST predictions of other centers
AUS/BoM
NOAA/CPC
summer
summer
ECMWF
UKMet
summer
summer

31. Summary and interpretation for June – August 2013
Numerical prediction
・ The JMA's coupled global circulation model predicts that the NINO.3 SST will be below normal into the northern hemisphere spring, and become near normal thereafter. Therefore, ENSO neutral conditions are likely to continue during the northern hemisphere summer The SST in the tropical Indian Ocean region (IOBW) will be near normal or below normal during the northern hemisphere spring and summer. The SST in the tropical western Pacific region (NINO.WEST) will be near normal during the northern hemisphere spring and summer.
・ The predicted atmospheric circulation anomaly pattern in the tropics and the sub-tropics is similar to that seen in the case of negative SST anomaly in the IOBW as stated below.
・ Three-month precipitation anomalies are predicted to be below normal in the equatorial Indian Ocean. On the other hand, they are predicted to be above normal from the Bay of Bengal to the east of the Philippines. The Tibetan high is predicted to be stronger than normal, and the subtropical jet, which flows along the northern edge of the Tibetan high, is likely to shift northward from its normal position. As a result, the North Pacific high is predicted to be stronger than normal over northern, eastern and western Japan. On the other hand, it is predicted to be weaker than normal over Okinawa/Amami.
・ The tropospheric thickness temperature averaged over the mid-latitudes of the Northern Hemisphere (30°N – 50°N), which is correlated with temperatures over Japan, is predicted to be slightly above normal.

32. Summary and interpretation for June – August 2013
Conclusion
・ As the characteristics of the atmospheric circulation around Japan, the North Pacific high is likely to shift northward from its normal position. Northern, eastern and western Japan are expected to experience above normal or near normal temperatures covered by the North Pacific high. Okinawa/Amami is expected to be influenced by moist southerly flow more frequently than normal.
Summary of the Outlook
・ Summer mean temperatures are expected to be both near normal and above normal with 40% probabilities in northern, eastern and western Japan. Summer precipitation amounts are expected to be both near normal and above normal with 40% probabilities in Okinawa/Amami. Precipitation anomalies during the Baiu period (rainy season) have no particular features for all regions.

33. Oceanic Condition and Outlook (1) Oceanic Condition in February 2013
Depth-longitude cross section of temperature and anomalies along the equator in the Indian and Pacific Oceans.
Monthly SST Anomalies
2011
2011
This figure shows sea surface temperature anomalies in February 2013.
We can see the negative anomalies in the central and eastern equatorial Pacific, and positive in the western part.
This indicates that La Niña like conditions.
I show you subsurface temperature anomalies along the equator .
Upper figure shows Depth-longitude cross section of subsurface temperature anomalies, lower figure shows Time-longitude cross section of ocean heat content anomalies.
We can see the positive anomalies in the western equatorial Pacific, and negative in the eastern part.
The positive anomalies expanded from the western part to the central part. Migration of the positive anomalies would weaken negative SST anomalies in the eastern equatorial Pacific.
Monthly mean outgoing longwave radiation (OLR) and anomalies
2012
2012
La Niña conditions are likely to have decayed.
Time-longitude cross sections of zonal wind anomalies at 850 hPa along the equator. 33

34. Oceanic Condition and Outlook Ocean Heat Content along the equator
Positive subsurface temperature anomalies were found in the western equatorial Pacific, while negative subsurface temperature anomalies were found in the central and eastern parts.
Depth-longitude cross section of temperature and anomalies along the equator in the Indian and Pacific Oceans. (Feb. 2013)
The positive anomalies expanded from the western part to the central part in February. Migration of the positive anomalies would weaken negative SST anomalies in the eastern equatorial Pacific.
Next, I show you subsurface temperature anomalies along the equator .
Upper figure shows Depth-longitude cross section of subsurface temperature anomalies, lower figure shows Time-longitude cross section of ocean heat content anomalies.
We can see the positive anomalies in the western equatorial Pacific, and negative in the eastern part.
The positive anomalies expanded from the western part to the central part. Migration of the positive anomalies would weaken negative SST anomalies in the eastern equatorial Pacific.
FEB
FEB
Time-longitude cross section of ocean heat content (OHC; vertically averaged temperature in the top 300 m) anomalies along the equator in the Pacific Oceans. (Jan. 2013)

35. Oceanic Condition and Outlook
OHC(ocean heat content)
WSX(Wind stress zonal wind)
SST(sea surface temperature)

36. SST Forecast and Anomalies (Jun-Aug mean)
The JMA's El Niño prediction model predicts that the current below-normal NINO.3 SST will gradually come closer to normal during the northern hemisphere spring. Although the model predicts above-normal NINO.3 SST in summer, uncertainties in the prediction is large for the later half of the prediction period . It is likely that current La Niña conditions will decay during the northern hemisphere spring. While development of El Niño conditions in summer may be possible, it is more likely that ENSO-neutral conditions will persist, considering bias characteristics in the model prediction.
Let me now turn to the NINO.3 SST forecast.
Left figure shows SST forecast and anomalies, and right one is a time series of the monthly SST deviation in NINO.3. Red line shows the observed SST deviation and yellow boxes show the predicted one. Each box denotes the range. The deviation will be included with the probability of 70%.
JMA’s numerical model predicts El Niño-like SST anomalies in this summer.
However, at the end stage of La Niña conditions in spring, the prediction of NINO.3’s SSTs in summer has relatively low accuracy.
SST Forecast and Anomalies (Jun-Aug mean)
The monthly SST deviation in NINO.3. 36

37. Oceanic Condition and Outlook (3) NINO.WEST and IOBW SST forecast
The SST in the tropical Indian Ocean region (IOBW) will be near normal or below normal during the northern hemisphere spring and summer.
The SST in the tropical western Pacific region (NINO.WEST) will be near normal during the northern hemisphere spring and summer.
IOBW
JJA
NINO.WEST
JJA
Let me now turn to the other SST forecast.
As you can see
The SST in the tropical Indian Ocean region (IOBW) will be near normal or below normal during the northern hemisphere spring and summer.
The SST in the tropical western Pacific region (NINO.WEST) will be near normal during the northern hemisphere spring and summer. 37

38. Oceanic Condition and Outlook (6) NINO.3 SST forecast
The current La Niña conditions are likely to end in spring and subsequent neutral conditions will continue during summer.
A time series of the monthly SST deviation in NINO.3.
Therefore, Our outlook of NINO.3 forecast is this. The current La Niña conditions are likely to end in spring, and subsequent neutral conditions will continue during summer.
Red line with closed circles shows the observed SST deviation and yellow boxes show the predicted one by the numerical model. Each box denotes the range where the deviation will be included with the probability of 70%.

39. Oceanic Condition and Outlook (7) NINO.WEST SST forecast
The SST averaged over the NINO.WEST region has been above normal since June It is likely that the SSTs in the region will become near normal in this summer.
A time series of the monthly SST deviation in NINO.WEST.
Last of Oceanic condition is the NINO.WEST SST forecast.
This figure is a time series of the monthly SST deviation in NINO.WEST. Line and box are the same as the figure of NINO.3.
The NINO.WEST SSTs have been above normal since June It is likely that the SSTs in the region will become near normal in summer.
Red line with closed circles shows the observed SST deviation and yellow boxes show the predicted one by the numerical model. Each box denotes the range where the deviation will be included with the probability of 70%. 39

40. Oceanic Numerical Prediction (5) Indian Ocean SST forecast
The SST averaged over the tropical Indian Ocean (IOBW) region has been below normal since December. It is likely that the SST in the IOBW region will gradually become near normal in the months ahead.
A time series of the monthly SST deviation in Indian Ocean.
Red line with closed circles shows the observed SST deviation and yellow boxes show the predicted one by the numerical model. Each box denotes the range where the deviation will be included with the probability of 70%. 40

41. Numerical Prediction MOS products（Guidance)
Summertime Temperature　2013
Probability(%)
MOS products
Below
Near
Above
Normal
Normal
Normal
Northern Japan 17 33 50
Eastern Japan 26 26 48
Western Japan 21 34 45
Okinawa/Amami(Southern Japan) 28 29 43
The outputs of Ensemble Prediction Systems are translated into probabilities of appearance for each temperature category( with a multiple regression scheme).
According to the numerical guidance, a hot summer is predicted with a high probability except for the Okinawa/Amami.
On the other hand, Okinawa/Amami has no particular features.
The numerical guidance are generated using Model Output Statistics (MOS) technique based on hindcast experiments.
Okinawa/Amami (Southern Japan) 41

42. Numerical Prediction MOS products（Guidance)
Summertime Temperature　2013
Probability(%)
MOS products
Below
Near
Above
Normal
Normal
Normal
Northern Japan 34 25 41
Eastern Japan 25 43 32
Western Japan 35 28 37
Okinawa/Amami(Southern Japan) 34 29 37
The outputs of Ensemble Prediction Systems are translated into probabilities of appearance for each temperature category( with a multiple regression scheme).
According to the numerical guidance, a hot summer is predicted with a high probability except for the Okinawa/Amami.
On the other hand, Okinawa/Amami has no particular features.
The numerical guidance are generated using Model Output Statistics (MOS) technique based on hindcast experiments.
Okinawa/Amami (Southern Japan) 42

43. Numerical Prediction (7) Skill of the Numerical Guidance
Reliability Diagram for temperature
Northern Japan
Western Japan
Eastern Japan
These figures show reliability diagram for summertime temperature with 4-month leadtime.
We can see good reliability except the northern Japan.
Southern Japan

44. History of seasonal forecasting in Japan
1942：
49：
74：
95：
96：
99：
2001：
02：
03：
06：
08：
10：
Official announcement of 1 month forecast (forecast section long range forecast staff)
Long range forecast section abolished
Long range forecast section established (17 staff members）
Begin assimilation of marine dat
Start of probabilistic forecast and introduction of forecasting one month ensemble numeric values
Start of El Nino prediction based on combined atmospheric and marine models
Start of long term atmospheric re-analysis
Begin assimilation of land surface data
Begin 3 month warm/cold season forecasts based on numeric prediction model
Completion of long term atmospheric re-analysis
Improvement of numeric forecast guidance and start providing early warning information on extreme weather
Begin seasonal forecast from combined atmospheric and marine model (CGCM:coupled global circulation model)
1942年：１か月予報を公式に発表（予報課長期予報掛）
　49年：長期予報課廃止
　74年：長期予報課設置（課員17名）
　95年：海洋データ同化の開始
96年：1か月アンサンブル数値予報の導入と確率予報の開始
　99年：大気海洋結合モデルによるエルニーニョ予測の開始
2001年：大気長期再解析に着手
02年：陸面データ同化の開始
03年：数値予報モデルによる3か月、暖・寒候期予報の開始
　06年：大気長期再解析完了
　08年：数値予報ガイダンスの改良と異常天候早期警戒情報の提供開始
　10年：大気海洋結合モデルを直接用いた季節予報の開始

45. Ｈ Ｈ Ｌ Ｌ Upper layer 上層 Lower layer Equator ●Supplementary information
Gill, A.E., 1980: Some simple solutions for heat-induced tropical circulation. Q. J. Roy. Met. Soc, 106,
Matsuno-Gill Response Model Ｈ Ｈ
Upper layer
Lower layer 上層 Ｌ
Ascending currents
Equator Ｌ
In response to an isolated heat source placed in the equatorial region,
equatorial Kelvin waves are generated in the east of the air circulation on the level surface and equatorial Rossby waves in the north-west and south-west,
which is called Matsuno-Gill response. In response to Rossby waves,
in the north and south sides of the equator,
the baroclinic structure of low pressure rotation is observed in the lower layer and that of high pressure rotation in the upper layer.
赤道上に熱源を置いた場合の松野-ギル応答。 コリオリ力が零値を取る赤道の周りには、赤道波と呼ばれる赤道に束縛された波のグループが存在する。
特に、赤道ケルビン波（赤道に対して対称で、赤道上で南北風速・南北気圧傾度は零）と
混合ロスビー重力波（赤道に対して反対称で、赤道上で南北風速は最大、東西風速・東西気圧傾度は零）は、赤道特有の波である。
これらの波の位相速度は熱帯平均場の風速に比べて早いため、熱帯域では降水に伴う熱源による赤道波の強制的な励起と
その減衰（摩擦・放射冷却・非線形項など）からなるバランスによって定常な大気循環が成り立つ。
降水に伴う熱源は対流圏中層に最大値があり、この加熱は水平の温度勾配の小さい熱帯域では上昇流による冷却とバランスする。
この結果、水平方向の大気循環は、対流圏上層と下層が逆位相である傾圧構造を示す。
　孤立した熱源を赤道に置くと、水平面内の大気循環は東に赤道ケルビン波、西にロスビー波が見られる。これを松野ーギル応答という（第2.5.1図の右中央図）。
赤道ケルビン波とロスビー波の東西の位置と広がりは、それぞれの波の位相速度（60m/sで東進と20m/sで西進）を反映している。
　　　　　　　 　Heat source
Heated by emission of latent heat (steam  raindrops)

46. Prediction accuracy
left : SST anomaly correlation initial 31Jan. Lead time 4 month
light : Rain anomaly correlation initial 31Jan. Lead time 4 month

47. Prediction accuracy
left : 200hPa stream function anomaly correlation initial 31Jan. Lead time 4 month
light : 850hPa stream function anomaly correlation initial 31Jan. Lead time 4 month

48. Prediction accuracy
left : 500hPa height anomaly correlation initial 31Jan. Lead time 4 month
light : S.L.P anomaly correlation initial 31Jan. Lead time 4 month

49. Skill of NINO3.4 SST Initial: February (1980-2001)
Initial: August ( )
1.0
0.8
0.6
0.4
0.2
0.0
1.0
0.8
0.6
0.4
0.2
0.0
Lead time (month)
At the end of the first topic, I will show you the skill of NINO3.4 SST according to the hindcast.
The each color line shows the Anomaly Correlation of the centers.
I would say that the prediction skill of the JMA’s CGCM is comparable to the top-level.
Lead time (month)
(JMA/MRI-CGCM)
NINO3.4 region: 120W-170W, 5S- 5N
(quote from Fig. 8 of Jin et al. 2008)

50. Oceanic Condition and Outlook Current Condition in February 2013
済：図（２月版）
未：ノート
Subsurface temperatures were above normal in the western equatorial Pacific, and below normal from the central part to the eastern part, and below normal in the western equatorial Indian Ocean.
ラベルがない？
This figure shows Monthly mean ocean heat content (OHC; vertically averaged temperature in the top 300 m) anomalies (Feb 2013.)
Subsurface temperatures were above normal in the western equatorial Pacific, and below normal from the central part to the eastern part.
And we can see negative temperatures in the western equatorial Indian Ocean.
Monthly mean ocean heat content (OHC; vertically averaged temperature in the top 300 m) anomalies (Feb.2013) 50

51. Summary of the Outlook
Summer mean temperatures are expected to be both near normal and above normal with 40% probabilities in northern, eastern and western Japan.
Summer precipitation amounts are expected to be both near normal and above normal with 40% probabilities in Okinawa/Amami.