January 2006

No. 3
Contents
Highlights of Global Climate for 2005

1

Climate Summary in Japan for 2005

2Global Temperature 2005: Second Warmest since 1891

3

Upgrade of JMA’s Global Data-Processing and Forecasting System
in March 2006

4

A Special Report on Extremely Cold Weather over Northeastern
Asia in December 2005 prepared

4

Highlights of Global Climate for 2005
Annual mean temperatures were above normal in most of theworld, and global mean surface temperature reached the second highest record since 1880. In the 2005 Atlantic hurricane
season, 27 named storms (previous records: 21) were observed.

ture of 44.1°C, which is more than 4 °C above normal, wasobserved in Allahabad in June. These conditions caused anumber of deaths of heat stroke over the regions.
(3) Heavy rain in western India (June to July)
From June to July, precipitation was significantly heavy
in central and western India. On 27 July, a record-breaking
rainfall of 944 mm was observed at Mumbai, India, whichcaused devastating damage such as over 1,000 deaths.
(4) Drought in Spain and Portugal (January to September)
Extremely light precipitation was observed in Spain andPortugal. The total precipitation in Madrid from January toSeptember was 82mm, which was only 29% of the normal.
It was reported that these drought conditions brought massive forest fires in Portugal, crop failure and reduced hydroelectric power supplies in Spain.
(5) Hurricanes in USA and Central America (July toNovember)
The 2005 Atlantic hurricane season set several records,
according to National Hurricane Center/NOAA, USA.
There were 27 named storms (previous records: 21) and 14
hurricanes (previous records: 12) formed in the AtlanticOcean. Extremely heavy precipitation was observed aroundthe Caribbean Sea. It was reported that some hurricanes
brought severe damage and fatalities to USA and Central
America; especially Hurricane 'Katrina' led to more than
1300 deaths along the central Gulf Coast in USA.
(6) Cold wave and heavy snow in East Asia and Europe(December)
In December, extremely low temperatures were observed
from southern Central Siberia to Japan and southwestern
Europe due to persistent cold-air flow from the Arctic. Record-breaking heavy snows were also observed in the Japan
Sea Side of Japan, including the record of maximum snow
depth in December of 58 cm in Akita. In Japan, more than
80 persons died due to the heavy snow. In northeastern
China, Korea and many areas of Europe, it was also reported
that heavy snow disrupted transportation such as airplanes
and trains.
(Hiroshi Nakamigawa, Climate Prediction Division)

1. Annual mean climate
Global mean surface temperature in 2005 was the second
highest since 1880 (for the details: http://okdk.kishou.go.jp/
news/topics_20060202.html). Annual mean temperatures
were above normal in most of the world, except western
Mongolia and western Australia, especially high in Siberia
to northern Europe, eastern China to South Asia, and mostof Australia (Figure 1). Annually total precipitation
amounts were above normal in northern Siberia, southern
Central Siberia to the central Arabian Peninsula, the coast ofChina to southern India, southeastern Europe, the west coastof Africa, central Canada, southwestern USA, and aroundthe Caribbean Sea, while they were below normal in eastern
Mongolia to northern China, southwestern Europe to northwestern Africa, Peru, and Australia (Figure 2).

2. Significant climatic events
Significant climate events and damage in 2005 are summarized below (Figure 3).
(1) Heavy rain and typhoons in East Asia (May to October)According to Tokyo Typhoon Center of JMA, 23 named
tropical cyclones formed in the western North Pacific in
2005, and the number of the cyclones was less than the1971-2000 average of 26.7. In early September, the typhoon “Nabi” hit Japan, causing severe damage such as 26
deaths and bringing record-breaking heavy precipitation of
1,321 mm for three days (4-6 September) in Nango Villagein western Japan, which was 2.9 times as much as its normalmonthly rainfall for September. There were 11 tropical cyclones causing damage to East Asia or the Indochina Peninsula. It was reported that the annually total number of fatalities caused by natural disasters related to heavy rain inChina reached 1800.
(2) Heat waves in India and Pakistan (June)
Northern India to Pakistan experienced extremely hotconditions in June. Monthly mean daily maximum tempera-Tokyo Climate Center

1No.3 | January 2006

Figure 2 Annual total precipitation ratio in 2005Categories are defined by annual precipitation ratio to normal(1971-2000 average)

Figure 1 Annual mean temperature anomaly in 2005
Categories are defined by annual mean of normalized monthly
temperature anomaly against normal (1971-2000 average)(2)Heat wave:Jun.
Allahabad India: Monthly mean daily maximum temp.in Jun.
44.1℃(around +4℃)(6)Cold wave, heavy snow:Dec.
Akita Japan: Maximum snow depth in Dec.
58cm (Normal 16cm)
Busan Korea: Monthly mean temp. in Dec.
1.2℃ ( -4.5℃)(4)Drought:Jan.-Sep.
Madrid Spain: Total prec. in Jan.-Sep.
82mm (29％)(1)Heavy rain,Typhoon:May-Oct.

(3)Heavy rain:Jun.-Jul.

Mikado Japan: Prec. on 4-6 Sep. 1,321mm(Normal monthly prec.in Sep. 471mm)
Taibei Taiwan: Monthly prec. in Aug.
751mm (251%)(5)Hurricane:Jul.-Nov.
Key west Florida USA: Monthly prec. in Aug.
337mm (251%)
Kigston Jamaica: Monthly prec. in Oct.
636mm (503%)

Mumbai(Bombay) India: Prec. on 27 Jul.
944mm (Previous record: 375mm)

Figure 3 Significant climate events and damage in 2005

C l i m a t e S u m m a r y i n Ja p a n f o r 2 0 0 5
The annual mean temperatures were near normal in most ofJapan except for Western Japan. Partly in the Pacific side ofWestern and Eastern Japan, the rainfall amounts were less thannormal through the spring and summer, resulting in serious shortages of water supply in summer. The Arctic cold air flowed out
into Japan and persisted through December, which resulted inrecord-low monthly temperatures and record-high snow depths ata number of observatories.
1. Annual mean climate (Figure 4)
The annual mean temperatures were near normal in mostof Japan except for Western Japan, where they were abovenormal. The annual precipitation amounts were below normal except for the Japan Sea side of Northern and EasternJapan and Nansei Islands. They were significantly below
normal in Tokai, Kinki and Shikoku districts, where five observatories in total recorded the lowest annual precipitation
amounts. The annual sunshine durations were below normal
in the Japan Sea side of Northern and Eastern Japan and inNansei Islands, and above normal in the Pacific side of Eastern and Western Japan.
2. Climatic features(1) Temperature variation (Figure 5)
From January to May 2005, the Arctic Oscillation (AO)
tended to be in its negative phase and occasionally caused
cold air surges over Japan. Through January and February,
winter monsoon patterns frequently strengthened with shortintervals, causing large fluctuation of temperature. Snowfall
amounts in the winter 2004/2005 were above normal in theJapan Sea side of Northern Japan and in the mountainous

Tokyo Climate Center2

areas of Eastern Japan, and near normal in the other regions. In May, the Okhotsk high dominated and brought
chilly weather to Northern Japan.
From June to November 2005, the AO tended to be inits positive phase and above-normal temperature dominatedover Japan. The record-breaking monthly mean temperatures were observed at many stations in June, Septemberand October.
(2) Partly drought condition in warm season
The onsets of the Baiu season were later than normal inmost of the regions. The withdrawals of the Baiu season
were earlier than normal except in Tohoku district, where it
was significantly later than normal by about two weeks. InJune, the Baiu front tended to be located off the southerncoast of Japan and near Nansei Islands, where record-highmonthly rainfalls were observed. The Baiu frontal zone
shifted northward to the southern part of Japan in the end ofJune and occasionally caused heavy rainfalls in some areas.
In some areas of Western Japan and the Pacific side ofEastern Japan, less-than-normal rainfall amounts were experienced during April to August, which resulted in serious
shortages of water supply in summer. Although the situation was partly relieved by the heavy rainfalls due to Typhoon 0514 (Nabi), the condition of water shortage continued locally in the Pacific side of Japan till the end of 2005.
(3) Tropical cyclones affecting JapanThe number of Tropical Cyclones (TC) with maximum
speed stronger than 17.2m/s formed in the western North
Pacific in 2005 was 23, which was below normal (Normal:No.3 | January 2006

26.7, range of near normal: 25-29). The numberof the landfalls on the mainland Japan was three,which was near normal (Normal: 2.6). The number of TCs that came within the range of 300kmfrom the mainland and islands of Japan was 12,

which was also near normal (Normal: 10.8).
In early September, Typhoon 0514 (Nabi) landed on Kyushu andHokkaido. Since it moved relatively slowly with its large stormywind area, record-breaking total rainfall amounts were observed atsome stations in Western Japan, and caused severe damage including
26 deaths.
(4) Cold early winterIn the middle of November, the AO rapidly turned to the negative
phase and the significantly negative phase persisted through December. Due to this, whole Japan was gripped by cold weather throughthe end of 2005, and lots of stations featured record-low monthly temperatures and record-high snow depths in December.
(Shunji Takahashi, Climate Prediction Division)

Figure 4 Annual Climate Anomaly/Ratio over Japan

Figure 5 Five-day Running Mean Temperature Anomalies for Subdivisions

G l o b a l Te m p e ra t u re 2 0 0 5 : S e c o n d Wa r m e s t s i n c e 1 8 9 1
The global surface temperature anomaly of 2005 was +0.32°C
above normal, and the second highest on record since 1891. JMA
started to monitor the global temperature combined over landand ocean at the beginning of 2006.
JMA monitors the global warming using data combined
not only over land but also over the ocean, instead of theland-only data from the beginning of 2006. The oceanic partof the combined data is the JMA’s original long-term sea
surface temperature analysis data, called COBE-SST (alsosee the articles in the “TCC News” No.1 and this issue)
The annual anomaly of global average surface temperatureduring 2005 was +0.32°C above normal (1971-2000 average), and was the second highest next only to 1998 since1891. The annual mean temperature over the globe has increased at a rate of 0.66°C per 100 years (Figure 6).
The annual-mean temperatures have varied in different
time scales ranging from a few years to several decades. The
increasing trend is likely due to human activities, particularly
the emission of greenhouse gases.
It is planned for the products of the global temperature
anomaly derived from the combined data to be routinely
posted on the TCC website from April 2006.
The procedure for estimating the global temperature
anomaly is as follows:
1) average monthly-mean temperature anomalies over landin each 5o x 5o grid box in the world;
2) average monthly-mean sea surface temperature anomalies

Tokyo Climate Center3

in each 5o x 5o grid box in the world where at least one
ship-observation exists;
3) average the anomaly in 1) and that in 2) according to
the ratio of land to ocean for each grid box;4) average the anomalies of all the grid boxes weighted
with the area of the grid box; and5) average monthly-mean global temperatures during theyear.
(Hiroko Morooka, Climate Prediction Division)

Figure 6 Annual anomalies of global average surface temperature from 1891 to 2005
The bars indicate anomalies from the climatological normal(1971-2000 average). The blue line shows five-year runningmean anomalies and the red line indicates the long-term linear
trend.

No.3 | January 2006

U pgrade of JMA’s Global Data-Processing and Forecasting System
in March 2006
The JMA’s Global Data-Processing and Forecasting System isgoing to be upgraded in March 2006. In parallel with this upgrade, it is planned that the systems of JMA’s climate analysis
and ensemble prediction and relevant products provided
through the TCC website (http://okdk.kishou.go.jp/) will bechanged.
1. The JMA’s Global Data-Processing and Forecasting
SystemThe JMA’s Global Data-Processing and Forecasting System is going to be upgraded in March 2006. The computing
power of the new super-computer system is 27.5Tflops(theoretical value) faster by about 36-times than that of theold one. Total sizes of main memory and the massive data
storage unit are 13.1TB and 2.0PB, respectively, and arelarger by about 25-times than those of the old one.
2. Atmospheric Analysis System
The JMA Climate Data Assimilation System (calledJCDAS), which is the same system as used in the Japanese
25-year Reanalysis Project (see the article in TCC NewsNo.2), will be adopted as a new operational system on 1stMarch 2006, following the current OI-version of Climate
Data Assimilation System. JCDAS provides real-time atmospheric and land surface analyses at a 6-hour interval (00,06, 12, 18 UTC) which are consistent with the JRA-25 data.
After completion of JRA-25 calculation in the end of March2006, JMA’s climatological normal of the atmosphere will
be replaced with that based on the JRA-25 data.
3. Oceanic Analysis System
The global Sea Surface Temperature (SST) analysis system, which is the same as used in the COBE analysis (seethe article in TCC News No.1), will be in operation fromMarch 2006. Main differences from the current analysis
system are the higher spatial resolution of one-degree meshinstead of two-degree one, and the improved quality control
and inter/extrapolation procedure. The new global SST,
called COBE-SST, will be utilized for the following pur-poses: El Niño monitoring, the initial condition for the El
Niño prediction model, the boundary conditions for JMA’s
Ensemble Prediction System (EPS) and JCDAS, and monitoring of long-term global climate change.
At the same time, we are planning to modify the index of
El Niño and La Niña. Main modification is to use a sliding
30-year average for the climatological reference instead of a
fixed reference of the 1961-1990 average now in use. The
details of the modification will be described on the “El Niño
Monitoring and Outlook” page on the TCC website in March2006.
4. Ensemble Prediction System (EPS)The extended-range EPS for one-month outlook will beseparated from the medium-range EPS for weekly weather
forecast. In addition, the global atmospheric prediction
model used in the EPS will be upgraded by adopting thesame schemes as adopted in the short-range global NWP
model in July 2005. The main changes are the introductionof a semi-Lagrangian scheme, the implementation of a newparameterization scheme for radiation process, and the utilization of the COBE-SST as oceanic boundary conditions.
One of the merits of this separation is that we can optimize
the initial perturbations for the extended-range prediction.
The number of the ensemble members will be increased from26 to 50, which is expected to help improve the probability
distribution of the EPS. The prediction model for the seasonal (three-month and warm/cold season) outlooks will beupgraded at the same time. A full-fledged hindcast experiment is planned in 2006 by using the empowered supercomputer system described in the section 1. The hindcast data,
along with the long-term reanalysis data (JRA-25), are expected to be useful to research on the predictability of theEPS and to develop application products derived from theEPS.
(1 and 4: Shingo Yamada, 2: Hiroshi Koide, and3: Tadashi Ando)A special Report on Extremely Cold Weather over Northeastern
Asia in December 2005 preparedIn December 2005, it was extremely cold over northeastern Asia, and averaged temperature over Japan was the lowest since 1948. One of the reasons for the cold weather issignificant meandering of the westerly jet influenced by thepersistency of the negative phase of the Arctic Oscillation.
Another reason was that the extremely active convectionover the Bay of Bengal, the South China Sea and the Philippine Sea was strongly related to the cold weather. A stationary Rossby wave train along the strong Asian jet, which wasexcited by the active cumulus convection over those areas,caused the persistent and large-amplitude meandering of the
Any comments or inquiries on this newsletter and/or
the TCC website would be much appreciated. Please email to the following address:
tcc@climar.kishou.go.jp(Chief Editor: Shingo Yamada)Tokyo Climate Centerjet, leading to the repetitive cold air outbreaks in and aroundJapan. But it remains to reveal the reason for the persistency of the active convection over the area, and it is necessary to examine whether the AO interacts with the stationary
Rossby wave excited by the active convection.
The special report about the extremely cold weather andthe active convection is available on the TCC website:
http://okdk.kishou.go.jp/news/topics_20060127.html(Shuhei Maeda, Climate Prediction Division)

Tokyo Climate Center (TCC), Climate Prediction Division, JMA
Address: 1-3-4 Otemachi, Chiyoda-ku, Tokyo 100-8122, JapanTCC website: http://okdk.kishou.go.jp/index.html

4No.3 | January 2006