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Project Leader	Prof. Yihui DING National Climate Center Beijing 100081 CHINA Tel: +86 10 6680 0013 Fax: +86 10 6217 6804 E-mail: yhding@public.bta.net.cn
Funding	US$ 85,000
Participating countries	Australia, China, Indonesia, Japan, Korea, Malaysia, Philippines, Thailand, U.S.A, Vietnam

Introduction/Background
It is well known that there are close relationships between ENSO phenomenon and anomalous climate through which socio-economic impacts in the tropical and other climatic zones have been produced. Numerous investigators have shown that the impacts of ENSO events on climate variability and extreme events, especially such disasters as floods and droughts, cold injuries and heat waves in summer seasons, and typhoons and tropical cyclones in the Asian and western Pacific Oceanic regions, are quite significant. It has caused the huge socio-economic losses and deteriorated environment in the APN region. Many studies have further revealed that there are some definite correlative relationships between the onset, mature and decaying stage of ENSO events, and Asian winter and summer monsoon. On the other hand, the anomalous sea surface temperature (SSTA) in the western Pacific Ocean may exert a teleconnection effect on the weather and climate in East Asia through PJ (Pacific-Japan) pattern or Walker circulation. Therefore, it is very necessary to improve our understanding and knowledge in these fields and very essential to enhance the monitoring and prediction of ENSO events and SSTA on the warm pool over the western Pacific Ocean at the seasonal and interannual time scales with necessary related information, products and data sets distributed to APN countries/regions via an Internet network.

Outline of activities conducted
A. Inception Meeting
On 16-17 September 1999, the project successfully held an inception meeting in Beijing. During the meeting, the recent research achievements were exchanged and the implementation plan of this project, the tasks and timetable for 1999-2000 as well as the renewal proposal for the APN Project for 2000-2001 were fully discussed with a final agreement being made for the further actions.
B. International Workshop
The international workshop on ENSO and SSTA over the warm pool was held successfully on February 27-29, 2000 in Shanghai, China. More than 20 experts from Australia, China, Hongkong of China, Japan, Korea, Malaysia, Philippines and the United States (NOAA/CPC and IRI) took part in this workshop. The recent research progresses made since the last inception meeting were reported and some key issues were fully discussed about the monitoring of tropical SSTA and its impacts on the climate change in East and South-east Asia as well as the prediction of ENSO with coupled models and statistical methods. During the workshop, the initial network system of this APN project was demonstrated by CNCC, and each of the other contributing countries/regions demonstrated its own homepage related with the monitoring and prediction of ENSO event and SSTA over the Warm Pool, on which basis a full network will be integrated with the inclusion of CNCC network system. Finally, some crucial problems, for example, the implementation and refinement of the network and its link to other networks over the world, were fully discussed.
C. Setting up the project network
A distributed network being able to monitor and predict ENSO events and SSTA over Warm Pool and to exchange related data sets has been initially set up at the second level of the homepage of National Climate Center of China, through which users are able to link to the homepage of each country participating at this project. A web-base platform for the project has been developed, some of which has been open for use. The website is http://www.ncc.gov.cn. The project network is generally composed of: 1) monitoring of ENSO signal, warm pool, tropical convection, monsoon, weather systems, 2) predictions of ENSO event by using dynamical and statistical models and outlooks of climate anomalies and typhoons, 3) historical view of selected El Nino/ La Nina events, 4) data related to the system. Among the above four components, lots of information are unique and different from the existing information easily accessible to users from other networks, for example, the monitoring data around the warm pool and South China Sea, the prediction of summer monsoon onset; the predicted monsoon rainfall distributions, the frequency of occurrence and tracks of tropical cyclones in western Pacific Ocean, and extreme weather and climate events in this region.
D. Research Activities
   Every participating countries of this project have organized and undertaken their national scientific research activities related to this project. The research focuses were placed on the meteorological and oceanic conditions in the warm pool area and the South China Sea, analyses of the activities of monsoon and tropical cyclones, such as the onset of Asian monsoon and the frequency of typhoon, investigations into the impacts of ENSO and warm pool SSTA on monsoon and tropical cyclones, the relationships between ENSO and extreme weather and climate events, and the development and improvements of ENSO prediction system which consists of both simple and complex dynamic atmosphere and ocean coupled models, coupled atmosphere and ocean model nested by regional oceanic model with high resolution, and statistic models in order to enhance the capability of predicting El Nino and La Nina events and warm pool SSTA on seasonal to interannual time scale. These studied are important to make our network more skillful and unique from others'.
E. Data Collection
Collected data relative to ENSO and the warm pool include intensive radiosonde observation data of the South China Sea region and adjacent sea areas from May to August 1998, oceanic observation data of the South China Sea region from May to August 1998 (including CTD data and ADCP dada), air-sea flux observation data at R/V Shiyan #3 and R/V Kexue #1, flux observation data of Xisha and Dongsha Island from May to July 1998.
F. Others
1.Operational monitoring and prediction of ENSO events and SSTA in the Warm Pool have been done by some of the countries/regions participating in this project.
2.Routine secretarial supporting work

Outcomes/Products
A. Project Network and Products
A network and its web-page (http://www.ncc.gov.cn ) of this project have been basically set up, with their catalogues and information residing on a workstation. China National Climate Center (CNCC) is responsible for maintenance of this network in the Internet, and collection and updating of the necessary information. Other participating countries/regions have furnished and is going to furnish information and data sets.
On the network, the catalogue of near-real time and historical products and electronic mails have been issued since January 2000, and ENSO information and monitoring bulletins as well as prediction of SSTA over the tropical Pacific in one year advance have been partially distributed to participating countries /regions on the irregular basis very soon. For example, the predictions of ENSO event and SSTA over Warm Pool for 1999-2001 have been issued to participating countries.
Among the four components of the network system, the monitoring is focused on identifying the atmospheric and oceanic precursor characteristics indicating onset of the ENSO in tropics. Over Warm Pool region, the monitoring of sub-layer SST by use of various sources of oceanic data is believed to be essential for early prediction of significant SSTA in this region. The information on the related weather systems, such as the East Asian monsoon, Walker circulation and Tibetan high, are included in this network. Historical view is to compare and demonstrate the different evolutions of SSTA for selected cases of El Nino/La Nina. For the prediction and climate outlook component of this network, the tropical Pacific SSTA is predicted through dynamic and statistical models of China, Japan, Korea and Australia, respectively. The time range of outlook covers monthly, seasonal and interannual time periods. Some digital data sets, such as SSTA, sub-layer temperature along 137°E, TBB, onset of summer monsoon, tropical cyclones and rainfalls in the participating countries, are available from this system. Those data sets are useful to describe the horizontal and vertical structure of atmosphere and ocean in this region, and to improve our understanding of the anomalous climate and weather in tropics, especially in the region of western Pacific Ocean.

B. Scientific Activities and Achievements
In the past year, our project has organized and undertaken lots of scientific research activities related to this project, which includes:
1) ENSO monitoring and prediction by Japan Meteorology Agency
2) Real-time monitoring of the broad-scale tropical circulation and ENSO in the Australian Bureau of Meteorology
3) Monitoring of the SST in the sub-layer of the warm pool area for improvement of the prediction of ENSO and climate anomaly in China
4) Some characteristic atmospheric and sea surface features associated with ENSO during the northeast monsoon in the Malaysian region
5) Impact of the South China Sea (SCS) SST variation on SCS summer monsoon and rainfall in Guangdong area of China
6) Mechanisms responsible for the switch between the warm and cold phase of ENSO
7) Preliminary study on impacts of ENSO upon East Asia and China
8) Climatological research for the Indonesia Maritime Continent
9) Impacts of 1997-1998 El Nino in the Philippines
10) Some new indices for ENSO and warm pool monitoring
11) The possible impacts of ENSO on climate anomalies in China
12) Prediction of ENSO with simplified coupled ocean-atmosphere model by CNCC
13) Impact of ENSO event on weather, climate , environment and social-economic development in Viet Nem
14) The characteristics of sea temperature and current in equatorial Pacific ocean during ENSO cycle
15) Simulated impacts of westerly burst on an El Nino event using the operational atmosphere ocean model of JMA, "Kookai"
16) El Nino and seasonal prediction by Japan Meteorological Agency
17) Real-time ENSO services and products of the Australian Bureau of Meteorology
18) On monitoring sea surface temperature anomalies over the Central and western equatorial pacific and predicting its potential effects on the Philippine climate and socio-economic environment
19) Variation of certain atmospheric and oceanic features over the Peninsular Malaysia- Eastern Indian Ocean region
20) An El-Nino prediction model with an intermediate ocean and statistical atmosphere system
21) An analysis of the anomalous activities of the East Asian summer monsoon in 1999
22) First transition of the Asian Summer Monsoon in 1998 and the effect of the Tibet -tropical ocean thermal contrast
23) Climate variation in precipitation data over the coastal area of Far East Asia associated with ENSO
24) Forecasts of tropical Pacific SST and sea level using a Markov model
25) Predictability of the interannual variation of the Warm Pool
26) Impacts of the sea surface temperature anomalies over the western-tropical Pacific Ocean and the South China Sea on the climate change over East Asia
27) ENSO numerical prediction system and some examples from 1997-1999 ENSO cycle
28) Interannual, decadal-to-interdecadal variation of tropical western Pacific Warm Pool during 1951-1998
29) Regional data assimilation system of Guangzhou Regional Meteorological Center
30) East Asian-Pacific air-sea correlation characteristics and the interdecadal variation

Trough the above studies on ENSO, warm pool, monsoon, typhoon, and their impacts on the soci-economic aspects and environments of APN regions/countries, we have obtained following scientific findings:
1) Two kinds of methods for ENSO experimental prediction have been developed: statistical and dynamical. For the latter, three versions of improved ZC model (1987), the improved Oxford model (1994) and high-resolution Indian-Pacific oceanic model have been used in CNCC. By utilizing these simplified ocean and atmosphere coupled models, the 1997-1999 El Nino/La Nina events have been successfully predicted. The Division of Climate Prediction of JMA has produced their experimental prediction of ENSO events with the JMA coupled ocean and atmospheric model. Long Range Weather Prediction Division of KMA has also conducted their experimental prediction of El Nino events with an intermediate ocean and statistical atmosphere coupled model system.
2) The Asian-Australian monsoon activity and its relationship with the structure of sea temperature over the Warm Pool and the socio-economic impact of ENSO events and SSTA over Warm Pool have been studied. The onset of East Asian summer monsoon is closely related to continuous increase in SSTA in the South China Sea, thus leading to the seasonal transition from winter to summer in East Asia. A couple of monsoon indices have been put forward to characterize the activity of Asian summer monsoon.
3) The important role of the warm pool on the climate in Asian and Pacific regions is shown up in causing vigorous growth of convective activity in this region and producing a tele-connection pattern. A wavelet analysis has shown that there are several significant modes of low frequency oscillation (LFO) for SSTA over the warm pool: intraseasonal, interannual and decadal. The anomalous behavior of the warm pool heavily depends upon the interannual and decadal LFO.
4) The studies on the effect of El Nino / La Nina events on climate conditions in East Asia and Southern Asia have shown that there is a definite relationship between El Nino event and precipitation pattern in East and Southeast Asia. In the second year of El Nino, the above-normal precipitation may be recorded in the extensive region to south of the Yangtze River and warm winter. The 1998 severe flooding in China is a very significant example. In La Nina year, the wet condition and active typhoons in Southeast Asia was observed. The 1999 summer is a good example. Therefore, the above-mentioned regions should be viewed as important regions significantly affected by ENSO events.

C. ENSO Forecast for 1999/2000
Monitoring and prediction of ENSO events and SSTA in the Warm Pool have been done by some of the countries/regions participating in this project. The operational forecasts of SSTA over the equatorial eastern Pacific has been made by using models in JMA, KMA, ABM and CNCC on experimental basis, separately, and the prediction information has been made available on the Internet basis. The prediction of the tropical Pacific SSTA for 2000 made in CNCC showed that the cold water in the equatorial eastern Pacific would continue to exist until September 2000. In addition, the prediction of precipitation and temperature patterns in China under the influence of 1999 La Nina has been made and issued, indicating that a winter (December 1999- February 2000) colder than previous 13 winters will occur in China. Now, it seems to be correct, in particular the very cold month of January 2000 was experienced.

Other Related Information
1. Two proceedings of the APN Project (#99012) Inception Meeting and the Workshop on Monitoring and Prediction of El Nino/La Nina and SSTA in the Warm Pool Area have been published (see Appendix 1 and 2). The recent research progresses in the areas of the monitoring of ENSO events, SSTA in the warm pool and their impacts on the climate change of East and Southeast Asia as well as the prediction of ENSO with dynamic models and statistical methods that have been made by the meeting participants from the participating countries of this project were collected in these two proceedings.
2. National Climate Center of China has issued El Nino/La Nina monitoring bulletins and warning reports on irregular basis, which are now distributed in China and will be distributed to other countries some times later.
3. Some data sets have been available in form of CD-ROMs, such as the 3D meteorological analysis of APN region, SSTA over the warm pool measured by TOGA-TAO and SCSMEX project, and other observations in this region.
4. Though this project, the skills and knowledge on monitoring and predicting ENSO events and SSTA in Warm Pool in developing counties/regions and APN region are to be enhanced.

Future directions/follow-up work
1.A detailed research report of this project will be published to summarize main academic achievements made by our project.
   2.A regularly maintained APN#99012 network and its periodic updating will be made for the future work.
3.A renewal project is needed to implement and refine the network.
With great endeavors of many contributing countries/regions, we have successfully achieved the goal of the APN Project#99012 in less than one year. As mentioned above, a network being able to monitor and predict ENSO events and SSTA over Warm Pool and to exchange related information has been basically set up. Numerous evidences suggest that the scientists of countries/regions participating at this APN project not only have capabilities of monitoring the atmospheric and oceanic real-time variability in Warm Pool area, but also have high skill of ENSO forecast by using their prediction models and methods. However, the establishment of the network of monitoring and prediction of ENSO events and Warm Pool SSTA is a complex engineering project. The network needs to be regularly maintained and continuously improved. Concurrently, we need to pursue our research activities which have been made with some significant findings: (1) important role of the warm pool in effect on the climate in Asian and Pacific region, (2) the Asian monsoon activity and its relationship to the structure of sea temperature over the warm pool and (3) the socio-economic impact of ENSO event and SSTA over the warm pool. These three issues are closely related to the scientific objectives of our project. Therefore, we need one more year (2000/2001) and further APN funding support to improve and maintain the network.