General Discussions March 6, 2009 Danang, Vietnam

Summary 37 presentations (25 Japanese, 8 Vietnamese, 1 American, 1 Chinese, 1 Taiwanese), Approx. 80 attendants. Cf. 1st WS in 2006: 23 presentations (12 Japanese, 11 Vietnamese), Approx. 50 attendants Various rainfall phenomena related with monsoon and their predictions in Vietnam and adjacent Asian monsoon region were presented.

March 4, 2009 Session 1. MAHASRI/AMY related projects (Chair: Dr. Nguyen Dai Khanh) The Workshop listened to the 5 following presentations: Current status of MAHASRI and AMY (MAHASRI/AMY) and related projects by Prof.Dr. Jun MATSUMOTO, Institute of Observational Research for Global Change (IORGC), Japan Agency for Marine-Earth Science and Technology (JAMSTEC)Department of Geography, Tokyo Metropolitan University Coordinated Energy and Water Cycle Observations Project (CEOP) by Prof.Dr. Toshio KOIKE, Department of Civil Engineering, The University of Tokyo Precipitation characteristics and assosiated environment regimes during SoWMEX/TiMEX by Dr. Richard H. Johnson, Department of Atmospheric Research, Colorado State University MAHASRI project – the initial results and pititions by Mr. LE Viet Xe, Mid-Central Regional Hydro-Meteorological Center Sharing and utilizing hydro-meteorological data in MAHASRI by Dr. Kooiti MASUDA, Frontier Research Center for Global Change (FRCGC)/ Japan Agency for Marine- Earth Science and Technology (JAMSTEC)

March 4, 2009 Session 1. MAHASRI/AMY related projects (Chair: Dr. Nguyen Dai Khanh) The speakers through their interesting presentations provided the workshop participants with a clear overviews of the MAHASRI, AMY, CEOP activities as well as other related experiments/projects in the region including SoWMEX and TiMEX that aim at estabilishing hydro-meteorological prediction system, particularly up to seasonal time scale, through better scientific understanding of Asian monsoon variability. The speakers welcomed all the interested researchers to participate and contribute to the development of current and future hydro- meteorological observations, data sharing and utilizing, simulations and predictions.

March 4, 2009 Session 2. Heavy rainfall and flood in Vietnam and Southeast Asia (Chair: Prof. Toshio Koike)

6 Session Summary “Heavy Rainfall and Flood in Vietnam and Southeast Asia” -Observation 1.Inter-comparison of precipitable water observed by GPS and AIRS in the Maritime Continents, Nobuhiko ENDO 2.Stable isotopes in precipitation at Da Nang, Vietnam, Kimpei Ichiyanagi

PWV time series at three GPS sites Seasonal variation was similar each other. Dry events well captured. AIRS PWV tends to drier than GPS PWV. AIRS Level-3 AIRX3STD.005 (daily)

Figure 3. Relationships between daily δD and δ 18 O in precipitation during whole period (left panel) and two periods (right panel). The results of river and lake water samples were also shown in the left panel. evaporation precipitation

9 Session Summary “Heavy Rainfall and Flood in Vietnam and Southeast Asia” -Observation -Pattern Classification 1.Inter-comparison of precipitable water observed by GPS and AIRS in the Maritime Continents, Nobuhiko ENDO 2.Stable isotopes in precipitation at Da Nang, Vietnam, Kimpei Ichiyanagi 3.Synoptic progress causing heavy rain in the summer monsoon onset in the North of Viet Nam, Pham Thi Thanh Huong 4.Time-space characteristics of heavy rainfall event in central Vietnam from mid- October to mid-November 2007, Kanamori Hironari

2. Synoptic patterns causing heavy rain in the first period of SM in the North VN 2.1 A cold front and its combination with other patterns 2.2. A tropical Cyclone and its combination with other patterns A monsoon trough and its combination with different patterns 2.4. Subtropical high-pressure and its combination with different patterns 2.5. Intertropical Convergence Zone and Intertropical Convergence Zone combined with different patterns

11 The patterns of the three heavy rainfall events were analyzed. The first event: the strong northeasterly over SCS. The third event: strong easterly from SCS to Cyclone Sidr.

12 Session Summary “Heavy Rainfall and Flood in Vietnam and Southeast Asia” -Observation -Pattern Classification -Flood Modeling 1.Inter-comparison of precipitable water observed by GPS and AIRS in the Maritime Continents, Nobuhiko ENDO 2.Stable isotopes in precipitation at Da Nang, Vietnam, Kimpei Ichiyanagi 3.Synoptic progress causing heavy rain in the summer monsoon onset in the North of Viet Nam, Pham Thi Thanh Huong 4.Time-space characteristics of heavy rainfall event in central Vietnam from mid- October to mid-November 2007, Kanamori Hironari 5.Severe floods in Central Vietnam simulated by the WRF-TRIP coupling system, Thanh NGO-DUC

03/2009 International MAHASRI/HyARC workshop T. NGO-DUC Page 13 WRF-TRIP coupling underestimations of WRF rainfall lead to systematic underestimation of river discharge simulated discharge reaches its maximum value in the same time with the observed one if a good estimation of rainfall is obtained, river discharge can be well forecasted using TRIP.

14 Session Summary “Heavy Rainfall and Flood in Vietnam and Southeast Asia” -Observation -Pattern Classification -Flood Modeling 1.Inter-comparison of precipitable water observed by GPS and AIRS in the Maritime Continents, Nobuhiko ENDO 2.Stable isotopes in precipitation at Da Nang, Vietnam, Kimpei Ichiyanagi 3.Synoptic progress causing heavy rain in the summer monsoon onset in the North of Viet Nam, Pham Thi Thanh Huong 4.Time-space characteristics of heavy rainfall event in central Vietnam from mid- October to mid-November 2007, Kanamori Hironari 5.Severe floods in Central Vietnam simulated by the WRF-TRIP coupling system, Thanh NGO-DUC

March 4, 2009 Session 3. Changes and variability of Southeast Asian monsoon. (Chair: Prof. Jun Matsumoto) 1. Long-term change/trend in heat & water balance in a lake on the Tibetan Plateau, seasonal movement of Baiu front in the northwest Pacific, seasonal and inter-annual climate variations in Vietnam, typhoon activity over the Philippines & South China Sea. 2. Conditions for torrential rains in Jakarta. 3. Intraseasonal and interannual rainfall variations in Bangladesh. ★ Need to clarify the relationship among changes in each region, those with global warming and/or decadal variations. ★ Need high quality long-term data. The data prior to 1950 will also be important, since most of the digitized high temporal data are available only after 1950.

March 4, 2009 Session 4. Modeling and prediction of Southeast Asian monsoon (Chair: Dr. Kooiti Masuda)

March 5, 2009 Session 5. Diurnal Cycle -1 (Chair: Prof. Tetsuzo Yasunari)

March 5, 2009 Session 6. Diurnal Cycle -2 (Chair: Prof. Manabu D. Yamanaka)

March 5, 2009 Session 7. MAHASRI Session (Chair: Dr. Nguyen Thi Tan Thanh)

Issues for Discussion Richard Johnson

Items for Discussion Model representation of diurnal cycle Compare models in more detail to observations, field experiment results Examine characteristics of diurnal cycle for precipitation type (large systems, small systems, etc.) Examine accuracy of boundary layer structure and diurnal evolution Examine surface fields (T, q, v, etc.) and surface fluxes

Items for Discussion Study of extreme rainfall events Carry out climatological studies of extreme rainfall events over all of East Asia (amount, duration, diurnal characteristics, TC-related or not, etc.) Investigate mesoscale conditions accompanying heavy rainfall (need to use radar data, surface, and other mesoscale observations)

Items for Discussion Climate change Investigate trends, multi-decadal variability of extreme rainfall events Same as above, except for tropical cyclone tracks (impacts on extreme rainfall) Same as above, except for monsoon onset/withdrawal dates, monsoon intensity

Discussion items (1) What are the necessary observations and/or data for MAHASRI in Vietnam?

Discussion items (2) What kind of model improvement is needed for better hydrometeorological prediction in Vietnam?

Recommendations (1) Implement Pilot Projects: - Make high temporal, fine resolution rainfall dataset using radar and in-situ observations - Conduct flood hindcast simulation experiments for a common target (basin, year, month, date): atmospheric + hydrologic simulation. Improve meteorological and hydrological observation network in Vietnam to meet the scientific requirement for MAHASRI. Need more intense mutual communication, for example, sending papers each other. Invite young (and senior) people to each country.

Recommendations (2) Organize national committee on MAHASRI in Vietnam. Enhance capacity building activities in scientific research in Vietnam. More opportunities should be given for young researchers in Vietnam, Japan, and other participating countries; opportunities such as exchange scholar, visiting program, participation to scientific conferences, higher educations, joint research, on the job training and field observations and surveys. Installation of new observation system including technical training for such observation is also recommended.

Recommendations (3) Further exchange of data and sharing information & idea should be promoted. Publication of a textbook summarizing the latest knowledge about the hydro- climatology in the South-East Asia will contribute for it. Continue this kind of workshop every two years.

Proposals (1) Conduct winter IOP in 2010 in collaboration with EAMEX. Data collection/archive activity should be enhanced. Publish special issue of MAHASRI/AMY/EAMEX (JMSJ?) Organize the next workshop maybe in March 2011 in Vietnam (where?)

Time Schedule of MAHASRI September, October, 2006: Planning and preparation phase September, October, 2006: Planning and preparation phase October, 2006-March, 2010: Research phase I ( : Build-up new observation systems) October, 2006-March, 2010: Research phase I ( : Build-up new observation systems) : IOP-year (AMY: Asian Monsoon Year) : IOP-year (AMY: Asian Monsoon Year) : Research phase II : Research phase II 2015: Concluding phase 2015: Concluding phase

Meeting Schedule in 2009 ・ March 5-7, 2009: The International MAHASRI /HyARC Workshop, at Danang, Vietnam ・ July 19-29, 2009: IAMAS at Montreal, Canada ・ August 11-15, 2009 AOGS th Annual General Meeting, at Singapore (Deat line: March 15!) AS08 AMY - a coordinated Asian Monsoon Experiment The 6th AMY Workshop (Planned) ・ August 24-28, 2009: The 6th International Scientific Conference on the Global Energy and Water Cycle Experiment and 2nd iLEAPS Science Conference, at Melbourne, Australia (Deat line: March 15!)