Planned Field Experiments in Asia

Takayuki Matsumura
Numerical Prediction Division
Japan Meteorological Agency

GEWEXGlobal Energy and Water Cycle Experiment
GAMEGEWEX Asian Monsoon Experiment
ADEOSAdvanced Earth Observation Satellite
GPSGlobal Positioning System
HUBEXHuai-He River Basin Experiment
KORMEXKorea Monsoon Experiment
TAPSTsukuba Area Precipitation Studies
TREXTorrential Rainfall Experiment
TRMMTropical Rainfall Measurement Mission

GEWEX (Global Energy and Water Cycle Experiment)/GAME (GEWEX Asian Monsoon Experiment)

GEWEX/GAME would promise to give a lot of benefit for very short- and short-range weather prediction research, though, as you are aware, GEWEX is a major sub-project of WCRP and GAME aims at elucidating climatological functions of the energy and hydrological cycles in the Asian monsoon region.

One of main objectives of GAME is to develop and improve comprehensive models of meso-scale atmospheric processes and regional or macro-scale hydrological processes and their interactions, i.e. the land-atmosphere interface scheme and/or cumulus cloud parameterization scheme, for GCMs and coupled atmosphere-ocean models in order to achieve better prediction and estimation of relatively short-range climate variability.

For this purpose and others, intensive regional experiments and satellite- based observations will be performed over the eastern half of the Eurasian Continent and the Maritime Continent during the period of main observation phase I (1997-2000). Taking account of various land surface conditions combined with large diversity in climatic conditions, typical 4 experimental field areas are selected as follows:

  1. Tropical monsoon region in southeast Asia
  2. Subtropical and temperate monsoon region in east Asia
  3. Tibetan Plateau and surrounding arid/semi-arid region and
  4. Permafrost region (Taiga and Tundra) in Siberia.

Each regional experiment consists of 2 or 3 individual experiments. Some of experiments will deploy a valuable 3 dimensional observation network over the regional scale river basins for investigating sub-synoptic- and meso- scale disturbances, others will establish a 1 or 2 dimensional array at limited areas to estimate the surface energy and water fluxes.

An Intensive Observation Period is scheduled for summer 1998, when all the regional experiments for GAME will be conducted with full observing systems available, including TRMM (Tropical Rainfall Measurement Mission), ADEOS (Advanced Earth Observation Satellite) and other satellites.

Chao-Phraya River Basin in Thailand (a constituent of GAME-Tropics (GAME-T))

The Chao-Phraya River basin of Thailand is located in the central part of the Indo-China Peninsula with area of about 200,000 km x km. In this sizable river basin, a large number of surface meteorological stations (of about 200) and hydrological stations are located. A Doppler radar system is also available in Thailand. Besides, radiosonde observations will be intensified up to 6 hourly operation during the period from March 97 to September 99. Various convective systems will be observed in this typical tropical monsoon climate with a noticeable variety in temporal and spacial distribution.

Whole observation data related to energy and water balance over the basin will contribute both the construction of a GCM grid scale hydrological model in the tropical humid region and the investigation of a method for soil moisture measurement from the space. (For details, please refer to

Huai-He River Basin Experiment (HUBEX; a constituent of GAME)

Rainfall phenomena in East Asia is closely associated with a subtropical front called the Baiu (or Meiyu in China, Changma in Korea) front during early summer.

The characteristic of the Baiu front is its multi-scale structure from meso to planetary scale. The activity of the Baiu front is greatly influenced by the Asian monsoon circulation coupled with the subtropical high over the north Pacific. The front system also plays a large role in longitudinal transport of energy and moisture in the northern summer.

On the other hand, the Baiu front is composed of medium- and meso-scale convective systems, which often cause heavy rainfall and associated severe flood and/or mud flow in this east Asian region. Cb cloud clusters are frequently formed in the front and sometime they are organized into meso-scale disturbances.

The field experimental study, HUBEX, will be performed around Huai-He River basin in China investigating energy and hydrological processes of multi- scale cloud systems in the Baiu front and their interaction with land surface hydrology. The deployment of the special network of radiosonde and surface stations, radar and Doppler radar systems, aircraft and satellites is expected.

TREX (Torrential Rainfall EXperiment)

To investigate severe meso-scale convective systems and associated torrential downpour in the Baiu front, an intensive field experiment was performed in southern Kyushu in Japan by Meteorological Research Institute (MRI), Communication Research Laboratory (CRL) and a number of universities during early summer in 1996.

The special observation network composed of radiosonde, video-sonde, Doppler radar, boundary layer radar, microwave radiometer etc. was implemented in the area in addition to operational radiosondes and radars. Two ships of Japan Meteorological Agency (JMA) and an aircraft from CRL joined in the TREX.

The CD-ROM containing all observation data during the TREX will be soon distributed to researchers who contribute the TREX.

The next TREX is planned in the summer of '98 and '99 over the western Kyushu and the East China Sea (proposed to Science and Technology Agency (STA)). The special observation network will be implemented in a similar scale to that of the previous TREX.

In addition, TRMM will contribute to the next TREX. Therefore, it will be also characterized as a TRMM validation study.

KORMEX (Korea Monsoon Experiment)

The KORMEX has been planned by researchers of Korea Meteorological Administration (KMA), Meteorological Research Institute of KMA (METRI) and Korea Monsoon Study Plan (KMSP) in collaboration with the GAME and South China Sea Monsoon Experiment (SCSMEX).

The main purposes of the KORMEX are to increase knowledge on the Changma front phenomena and to enhance predictability of NWP. The observation network composed of radiosonde stations, surface stations (of about 400) and radar systems is implemented over the southern half of the Korea Peninsula.

Cooperative study of GPS meteorology in Japan

A study on GPS (Global Positioning System) meteorology is planned in cooperation with Geographical Survey Institute (GSI), JMA, MRI and other research institutes and universities in Japan (proposed to STA).

The GSI has established a nationwide GPS array of 610 ground-based stations in Japan (one in every 25 km x 25 km) and plans to increase the number of stations up to 860 by the end of March 1997. The primary objective of the network is to monitor the tectonic deformations and to support earthquake prediction research.

Atmospheric moisture fluctuation obstructs the precise diastrophism measurement, since atmospheric water vapor causes delay in the phase of microwave signals from GPS satellites. From the meteorological point of view, however, a ground-based GPS receiver can be regarded as a sensor for total precipitable water overlying the station.

Objectives of the cooperative study are as follows:

  1. to validate GPS total precipitable water through comparison with simultaneous radiosonde and/or microwave radiometer,
  2. to improve the accuracy of NWP by assimilating GPS moisture data,
  3. to improve the accuracy of geodetic survey by making use of the NWP data,
  4. to understand the structure and mechanism of local circulations and meso- scale convective systems by analyzing GPS moisture, radar, radiometer, radiosonde data, surface station data and NWP and
  5. to archive the atmospheric water vapor data for researchers of hydrology and other fields as well as meteorology and geodesy.

Intensive field campaigns are under consideration in several areas in Japan taking account of different topographical situations and seasonal variability of atmospheric conditions.

TAPS (Tsukuba Area Precipitation Studies)

The Kanto Plains located in middle east of Japan is the largest plains in Japan with area of about 13000 km x km where Tokyo metropolis and Tsukuba Science City are located. There are a number of institutes and universities which have immovable facilities observing meso-scale disturbances in the Plains. Moreover, typical meso-scale disturbances such as thunder storms, coastal fronts, cold air damming and tornados often occur there as well as Baiu frontal storms and typhoons.

TAPS is a long-term agreement on cooperative observation and data exchange among institutes and universities in the Kanto Plains. They perform simultaneous campaigns against common phenomena gathering their own facilities such as Doppler radar, wind profiler, microwave radiometer and so on. They can operate dual Doppler analysis making use of individual radars.

They will play an important role in GPS meteorology and TRMM varidation study.


This report is compiled for the Meeting of WMO/CAS Working Group on Very Short- and Short-Range Weather Prediction Research (Tulouse, Nov. 1996). I would like to express my sincere thanks to Drs. Kentaro Ando (JAMSTEC), Toshiki Iwasaki (NPD/JMA), Zen-ichiro Kawasaki (Osaka University), Fujio Kimura (University of Tsukuba), Ken-ichi Kuma (NPD/JMA), Hajime Nakamura (MRI/JMA), Nobutaka Noguchi (MRI/JMA), Yoshimitsu Ogura (JWA), Jai-Ho Oh (METRI/KMA), Taikan Oki (Goddard Space Flight Center), Deuk-Kyun Rha (METRI/KMA), Nobuo Sato (NPD/JMA), Takehiko Satomura (Kyoto University), Naoko Seino (MRI/JMA), Dong-Hyun Shin (KMA), Kazuhisa Tsuboki (ORI, University of Tokyo), Mitsuru Ueno (MRI/JMA), Akira Watanabe (Fukushima University) and Masanori Yoshizaki (MRI/JMA) for their very valuable comments and suggestions on this report.

Acronyms: CAS (Commission for Atmospheric Sciences)
JAMSTEC (Japan Marine Science and Technology Center)
JMA (Japan Meteorological Agency)
JWA (Japan Weather Association)
KMA (Korea Meteorological Administration)
METRI (Meteorological Research Institute/KMA)
MRI (Meteorological Research Institute/JMA)
NPD (Numerical Prediction Division/JMA)
ORI (Ocean Research Institute)
WMO (World Meteorological Organization)

Dr. Takayuki Matsumura
Numerical Prediction Division
Japan Meteorological Agency