A Brief Introduction to the National Project for Developing Basic Sciences

in China (2004-2009)

Theories and Methods for Monitoring and predicting Heavy

Rainfall in South China

Chinese Academy of Meteorological Sciences (CAMS)

Beijing, 100081

Renhe Zhang ( 张人禾 )

1. Motivation and Scientific Issues

The heavy rainfall in South China includes the The heavy rainfall in South China includes the Meiyu FroMeiyu Front heavy rainfallnt heavy rainfall in the middle and lower reaches of Yangtz in the middle and lower reaches of Yangtze River vally, e River vally, pre-monsoon pre-monsoon heavyheavy rainfall in South Chinarainfall in South China a and nd typhoon heavy rainfalltyphoon heavy rainfall. .

The floods cauThe floods caused by the heased by the heavy rainfalls are vy rainfalls are the primary mthe primary meteorological deteorological disasters in Chiisasters in China.na.

annual economi c l osses caused by meteorol ogi caldi sasters(uni t:108 RMB)

0

500

1000

1500

2000

2500

3000

1949 1956 1963 1970 1977 1984 1991 1998

In resent 10 years, the flood disasters caused almost In resent 10 years, the flood disasters caused almost hundreds to thousands of losses of human life and around hundreds to thousands of losses of human life and around 200 billion RMB of economic losses each year.200 billion RMB of economic losses each year.

It can be seen,It can be seen, there is great significthere is great significance to study heavy rainfall for the imance to study heavy rainfall for the improving of the monitoring and forecastproving of the monitoring and forecasting capability of heavy rainfall in ordeing capability of heavy rainfall in order for enhancing national ability to mitir for enhancing national ability to mitigate and prevent natural disasters and gate and prevent natural disasters and insuring sustainable development of soinsuring sustainable development of society and economy in China. ciety and economy in China.

However, the forecast ability for heavy rainfall has not However, the forecast ability for heavy rainfall has not yet been improved greatly. yet been improved greatly.

AREM_3DvarAREM_3DvarForecast 25.0Forecast 25.0mmmm/24Hr rainfall TS /24Hr rainfall TS

AREM_3DvarAREM_3DvarHLAFS0.25HLAFS0.25

T213T213

For the heavy rainfall For the heavy rainfall with the precipitation of 465mmwith the precipitation of 465mm in Wuhin Wuhan on Jul 21-23,1998, TRMM data display the heavy rainfall procan on Jul 21-23,1998, TRMM data display the heavy rainfall process were associated with cloud clusters of the ess were associated with cloud clusters of the spatial scale of spatial scale of tens tens to hundreds kilometer (meso-to hundreds kilometer (meso- scale) scale)..

Meiyu Front and Meso-scale Convection Cloud Tower

This study meso-β scale system

Former study: meso-α scale system

Strong convective cloud cluster made a surprise attack on Shanghai at 17:30-19:30 Jul 12 2004 causing gale(29m/s) and heavy rain disaster.

It is shown by satellite data that dIt is shown by satellite data that during this period convective systemuring this period convective systems with the s with the spatial scalespatial scale of of tens kilotens kilometermeter successively attacked Shang successively attacked Shang

hai .hai .

17:25

Satellite data Satellite data shows that shows that during this during this period period convective convective systems with systems with the spatial the spatial scale of tens scale of tens kilometer kilometer successively successively attacked attacked Shanghai .Shanghai .

Rananim in 2004: the strongest Typhoon landing China in the past 50 years

The maximum precipitation is 916 mm. And caused geologic disasters such as stream of mud-stone and mountain slippage .

It caused tragic losses in Zhejiang province: 164 death ， 24 disappearance ， 1800 hurt,direct economic losses of 18.128 billion yuan 。

02:33 Aug 12 2004 (GMT)TERRA ／ MODIS for Rananim

通道 31通道 1/6/31

What is the mechanism for the What is the mechanism for the strong convective cloud strong convective cloud clustersclusters of ten to hundred kilometer scaleten to hundred kilometer scale appeared in the appeared in the Typhoon cloud belt ofTyphoon cloud belt of thousands kilometer scale? What is the thousands kilometer scale? What is the relationship between them?relationship between them?

The above mentioned examples sThe above mentioned examples show clearly that the weather systehow clearly that the weather systems causing severe heavy rainfall ams causing severe heavy rainfall are re strong convective heavy rainfall strong convective heavy rainfall clusters with the clusters with the spatial scalespatial scale of tens tens to hundreds kilometersto hundreds kilometers. The study . The study of the weather system of Meso-of the weather system of Meso- sc scale has great scientific significance.ale has great scientific significance.

Why this kind Why this kind of convective cloud of convective cloud clusters with 10-10clusters with 10-1022 km km spatial scale can be spatial scale can be developed so developed so intensively?intensively?

Why there is so Why there is so powerful energy collecting powerful energy collecting environmental vapor to a environmental vapor to a smaller area in a short smaller area in a short period and raising to an period and raising to an altitude to form heavy altitude to form heavy rainfall?rainfall?

What are the cloud What are the cloud physical processes of this kiphysical processes of this kind of heavy rainfall?nd of heavy rainfall?

How to detect the pHow to detect the physical parameter associatehysical parameter associated with the heavy rainfall in d with the heavy rainfall in this kind of mesoscale clustthis kind of mesoscale cluster?er?

How to How to improve forecast of improve forecast of the heavy rainfall the heavy rainfall triggered by strong triggered by strong convective cloud convective cloud clusters?clusters?

Scientific Scientific IssuesIssues

Non-static high-resolution heavy rainfall numerical forecast model system.

Theory and method that caTheory and method that can merge and assimilate data n merge and assimilate data from multi-detecting inforfrom multi-detecting information to a mesoscale metemation to a mesoscale mete

orological fields.orological fields.

To establish the physics To establish the physics for strong convective for strong convective

cloud cluster in South cloud cluster in South China.China.

Scientific Goals

Scientific Goals

2. Research Scheme

Seven themes of the projectSeven themes of the project

Formation Mechanism

study

1. structure and formation mechanism of heavy rain cloud cluster in South China

2. Study on the effect of external forcing and large scale circulation anomaly on heavy rainfall process in South China

3. Study on the climate background associated with persistent heavy rainfall in South China

Monitoring Theory Study

4. In situ experiment on mesoscale heavy rainfall observation system

5. Remote sensing theory and method for explorer the heavy rainfall system and its application in data assimilation

Seven themes of the projectSeven themes of the project

Forecast and nowcast Theo

ry Study

6. Study on the basis theory for meso scale heavy rain forecast in South China

7. The development and establishment for non-static high resolution mesoscale numerical forecast model system

Seven themes of the projectSeven themes of the project

3. Research Group and Field Experiments

Attending institutionsChinese Academy of Meteorological SciencesChinese Academy of Meteorological SciencesInstitute of Atmospheric Physics, Chinese Institute of Atmospheric Physics, Chinese

Academy of sciencesAcademy of sciencesNational Satellite Meteorological CenterNational Satellite Meteorological CenterNational Meteorological CenterNational Meteorological CenterBeijing UniversityBeijing UniversityNanjing UniversityNanjing UniversityNanjing Institute of MeteorologyNanjing Institute of MeteorologyWuhan Institute of Heavy Rainfall, CMAWuhan Institute of Heavy Rainfall, CMA

About 80 scientists

南方致洪暴雨外场试验示意图

Field Experiment