International Monsoon Studies (IMS) under WCRP cross-cut studies

Tetsuzo YasunariHyARC, Nagoya University &FRCGC/JAMSTEC, Japan

• Background • Summary & recommendation of 1st Pan-WCRP Monsoon WS in June 2005, Irvine,CA• JSC recommendation, March 2007, Zanzibar• 1st IMS planning WS in September 2007, Bali, Indo

nesia

Challenges in monsoon system study• The monsoon systems are manifested as land-atmosphere-

ocean coupled systems, exhibiting a variety of time and space scales that are governed by complex physical processes and their interactions.

• Due to our lack of understanding these processes and interactions, large uncertainties still exist in prediction of the monsoons on local, regional, and continental-scales.

• Monsoon predictions require better models, and better models require improved physical parameterizations, which in turn require more comprehensive observations. 

• Since the monsoon systems possess a large range of variability from diurnal to decadal time scales, prediction is a challenging test for the modelling community. 

• Given the importance of the monsoons in driving the energy and water cycle, improving model physics in monsoon regions will result in better models for other applications such as global change, and water resource assessments.

Organizing committee:T. Yasunari (Co-chair), K. R. Sperber (Co-chair), W. Higgins, K.M. Lau, J. McCreary, C.R.Mechoso, J. Polcher, K. Puri, J. Slingo, C. Thorncroft, B. Wang, G.-X., Wu

This workshop was a unique and timely opportunity to promote a new initiative of the pan-WCRP monsoon system prediction studies,which should be an essential part of the new WCRP strategy. (Sperber and Yasunari, BAMS, 2006)

• Targeted workshops are envisioned as an important mode of interaction for sustaining CLIVAR and GEWEX interactions. These can be held in conjunction with existing panel meetings, as sessions at conferences, or independently.

• The near-term (1-2 years) goal is to improve the simulation of the diurnal cycle of precipitation and convection in global models by making use of regional climate models and cloud-resolving models that have more comprehensive physics. This is seen as the primary near-term goal that will crosscut the expertise of CLIVAR and GEWEX.

• The seasonal cycle of the monsoon is also a challenge for GCMs, showing too early (or late) onset of the Asian and north American monsoon.

WS recommendations (selected) #1

• Improved modeling of the intraseasonal oscillation, with large-scale convection in the tropics on a time scale of ~30-70 days. This phenomenon straddles numerical weather prediction and climate, and is a potential source of predictability that has not been realized due to its poor representation in models.

• Need for more process studies and modeling of the Maritime continent and the Indian Ocean.

• Better understanding of the atmospheric moisture distribution and transport.

• Sensitivity testing to determine the resolution necessary in global models to simulate multi-scale interactions that dominate the Earth’s monsoon systems.

WS recommendations (selected) #2

• The decay of the present observing system needs to be reversed.⇒role of GEOSS is important!

• Improved (and sustained) observations are needed over sparsely sampled regions of the tropical oceans, especially the Indian Ocean.

• Better observations of land surface conditions are needed (e.g., soil moisture, snow cover, snow depth) for understanding processes, and because these quantities can serve as boundary conditions for model simulations.

• The role of aerosol and dust and its impact on the development of monsoon precipitation should be investigated, though at present these may be secondary to errors in the basic structure of monsoon simulations.

WS recommendations (selected) #3

Decision at The 28th Session of The Joint Scientific Committee (JSC), WCRP

at Zanzibar, Tanzania, 26-30, March 2007)• Endorse the WCRP crosscutting Monsoon Initiative. T

he JSC commented that the monsoon crosscut should include all the monsoon groups with a broader perspective, led by CLIVAR and GEWEX with participation of SPARC, CliC and WGNE and several activities outside WCRP (particularly THORPEX).

• Request CLIVAR and GEWEX to agree on how it will be supervised and the development of an implementation plan.

• The proposals for and concepts of an Asian Monsoon Year and an International Year of Tropical Convection should be considered as components of an International Monsoon Study (IMS) 2007-2011, a 5year strategy of WCRP monsoon research, which would include issues related to the East African Monsoon, capacity building and application of observations and predictions in monsoon regions for societal benefit.

THE WCRP RESOURCE TREND IN WCRP AGREED TO BY JSC IN ZANZIBAR:

WGCM

WGNEMONSOONS

EXTREMES

DECADAL AND ISACC

AC&CIPY

$ $$ $

$

$ $$/N $/N

$

PRE - 2008

$

2008 AND BEYOND

$/N

$ $

$

ISSUE: WHAT IS “$/N” AND HOW WILL IT BE DISTRIBUTED??

GEWEX/CLIVAR

CLIVAR/GEWEX

CliC

SPARC

CLIVAR

GEWEX

Societal needs for IMS

• More than 60% of the world population live under monsoon climate, and receive benefits as well as damages from monsoon precipitation and hydrological processes.

• Most of the countries under monsoon climates are developing or semi-developed countries, where coordination for monsoon prediction is highly required, including common or integrated capacity buildings (observation systems, modeling & prediction sytems, training seminars, WSs,etc.) through WMO and WCRP framework. (WMO-WCRP coordination is very essential.)

•. Large uncertainities exist in predicting (or projecting) all the regional monsoon climates associated with the ongoing and future anthropogenic changes (GHGs increase, aerosol increase, and LCLU changes) due to lack of understanding hydro-climate processes of monsoons. (e.g., refer to IPCC-AR4 2007).

Objectives of International Monsoon Studies (IMS)

(results of discussion in Bali, Sep.2007)• Improve forecasts from intra-seasonal to inter-annual

time-scales in monsoon regions• Improve our understanding of the relative role of land

and oceans on diurnal to interannual (decadal) time scales.

• Improve our understanding of (natural & anthropogenic) climate change on monsoons

• Enhance the observational networks and data utilization

• Enhance the collaboration among regional monsoon research communities

• Facilitate the use of knowledge on monsoon climate in societal impact studies

Organization of IMS sccoping group (SG) under WCRP-JSC (tentative)

• From JSC Monsoon Oversight Group (JMOG) (Wu.G.X., T.Yasunari, J.Slingo, J.Shukla, C.Vera, L.Ogallo)• From CLIVAR/GEWEX Monsoon Panels&WGs (J. Matsumoto, B.Wang, J.Polcher, H. Berbery, OCEANS)• From CEOP (T.Koike, K.M.Lau)• From THROPEX (YOTC) (H.Hendon?) • From MAIRS and others (C.B. Fu, B. Goswami)• From WMO monsoon study committee (C.P. Chang)• (exofficio) IPO directors of CLIVAR and GEWEX

• Multi-scale interactions from meso-scale to planetary-scale are essential for dynamics and prediction of ISV and seasonal march of monsoons, which include time scales from DC to ISV and SC.

• Global-scale simultaneous satellite observations with high-resolution (with space & time) are essential for resolving these interactions, through 30m. to 1hr obs. of the geostationary met. satellites.

• In-situ regional observations relevant to various international/national projects should be optimized in conjunction with the intensive satellite observations (mentioned above). ⇒ 　 AMY08/YOTC

• Reanalyses(including DC resolution) based on the data of these IOPs (for boreal summer and winter monsoon) and cloud-resolving GCM (e.g., NICAM in the Earth Simulator) experiment will provide invaluable data for improving daily to seasonal predictions.

Scientific rationales for near-term IMSwith AMY08/YOTC

ISV (MISO)

• Most of variances in SC is occupied by ISV.• Most of extreme events occurs associated

with ISV• Dynamics of ISV is still unknown, and low p

redictabilty is related to uncertainty of ISV.• ISV dynamics is likely to be closely linked to

intreactions with DC and SC.

Multi-scale interaction in the tropics and monsoon regions

DC ISV SC

Land-Atmosphere-Ocean IneractionsOrographic forcings

IAV

Solar forcings

00-05LT

[mm/hr]

Diurnal cycle of rainfall by TRMM-PR

The most humid area in the tropics show large DC in time-space.

(Ichikawa and Yasunari, 2006 J. Climate)

MJO disturbance developed between Jan to Feb in 2001

OLR and wind (850hPa)

Jan21-31

Feb1-10

Feb11-20

Feb21-28

ISO propagated through the islands,with apparent Kelvin-Rossby response.

Ichikawa and Yasunari, GRL 2007In press.

Time-longitude section of rainfall between Eq-5S

Fine structure of MJO shaded ・・・ OLR( － 190 － 240 －　 [W/m2])white ・・・ zonal wind at 600hPa(solid:2,dash:10[m/s])color ・・・ diurnal cycle filtered rainfall 0.2, 0.4 [mm/h]

15‐20m/s

Propagating rainfall activity associatedwith the diurnal cycle over and aroundthe island

↓↓Propagating diurnal disturbance (PDD)

(Ichikawa and Yasunari, 2007 GRL, in press)

Meso-scale disturbances originated from DC convective sytem over Tibetan Plateau

(Yasunari and Miwa, JMSJ, 2006)

Eastern Edge of Plateau

Tibet P. Tibet P.

Seasonal & intraseasonal variations of Meiyu rainfall in China

Fujinami and Yasunari, 2008, MWR submitted

Two types of ISV circulations along

Tibetan Plateau

Fujinami and Yasunari, MWR, submitted

All Bangladesh Monsoon Rainfall shows extremely large ISV amplitudes with 10-20 days.

ISV determines rainfall amount of IAVof ABMR

Hatsuzuka, Fujinami & Yasunari(2008)

Latitude-time section of Tbb along Bangladesh longitudesJuly 1999.

Southward propagation of DCs are embedded In the southward propagation of ISV .

the 2nd Pan-WCRP monsoon Workshop

• One possible candidate date/venue will be in conjunction with the 4th WMO monsoon conference to be held in October 2008, in Beijing, China.

(with the first outcome of the AMY?)• Joint session (e.g., diurnal cycles, ISV etc.) can be

possible. Topics of the workshop also needs to be determined (tentatively).

Diurnally-developed convergence line in some cases expand toward the eastern edge of the Plateau, to form meso-αsystems over Meiyu Frontal Zone (Plateau Edge Cyclogenesis:PEC) 　 (Yasunari and Miwa, JMSJ, 2006)

High-resolution GAME RA data used

Abnormally heavy flood occurred

in southeast Asia during winter monsoon surge

in 2006/2007

This extreme event occurred in abnormally warm winter monsoonin east Asia (under the global warming trend?!).

Rainfall amount and mean low-level(925hPa) circulationsduring heavy rainfall events of 17Dec.-20Dec.2006

15DEC 16DEC 17DEC

18DEC 19DEC 20DEC

Time-sequence of V 925hpa Strong NE monsoon surge

was likely to cause heavy rainfall events.

Heavy rainfall was modulated by diurnal cycle of meso-scale convective systemtriggered by winter monsoon cold surges.

2N-6N 　 Average

Flood over Malay peninsula → 　 stagnant rainfall

Flood over Malay peninsula → gradual eastward propagation

Heavy rainfall over Jawa

MJO

Heavy rainfall events were alsoassociated with MJO from IO.

MORE DECISIONS FROM ZANZIBAR

JSC DECISIONS FROM ZANZIBAR:

- NEED TO DEVELOP A GLOBAL CROSS-CUTTING MONSOON PROGRAM FOR THE 2007- 2011 PERIOD.- SHORT TERM TEAM (< 1 YEAR) NEEDED TO DEVELOP AN IMS STUDY PLAN (JSC REPS, PROJECT LEADS: J MATSUMOTO, BING WANG, OTHER MONSOON REGIONS/PANELS)- STRONG LINKS SHOULD BE MADE WITH YOTC AND THORPEX.- WCRP MONSOON CROSSCUT SHOULD BE DEEPLY ROOTED IN CLIVAR AND GEWEX PROJECTS.- JSC ESTABLISHED A TEAM TO BE RESPONSIBLE FOR OVERSIGHT OF THE MONSOON CROSSCUT- CLIVAR AND GEWEX WILL RATIONALIZE THE NUMBER OF MONSOON COMMITTEES

SUBSEQUENTLY……CLIVAR AND GEWEX IPOs INITIALLY PROPOSED A SMALL MEETING1 TODEVELOP A CONCEPT PAPER THAT WOULD: - PROVIDE A GLOBAL STRUCTURE THAT INTEGRATES REGIONAL EXPERIMENTS AND PROMOTES COHERENCE AMONG THEM. CONCEPT PAPER SHOULD INCLUDE: - CLEAR SET OF AIMS AND OBJECTIVES - SET OF PRIORITY SCIENCE QUESTIONS - SOME GUIDELINES FOR IMPLEMENTATION - CONTRIBUTION TO APPLICATIONS AND CAPACITY BUILDING.

JSC HAD APPROVED THE IDEA OF A SECOND PAN-WCRP MONSOONMEETING WHICH WAS TO BE LED BY PROF. T. YASUNARI. THIS MEETINGIS A RESPONSE TO THIS RECOMMENDATION.

THIS MEETING COULD SERVE AS A SUBSTITUTE FOR THE NON-EVENTBY INITIATING A PROCESS TO DEVELOP THE IMS PLAN NEEDED FORTHE GEWEX AND CLIVAR SSG AND THE NEXT JSC MEETING ANDDEFINING THE NEXT PAN-WCRP MONSOON SCIENCE WORKSHOP.

1- MEETING NOT HELD DUE TO A LACK OF RESOURCES FOR TRAVEL (AND TIME)

ISSUES:

SCIENCE PLAN:1) WHAT ARE THE FUNDAMENTAL SCIENCE QUESTIONS THATCUT ACROSS ALL MONSOON RHPS AND ARE LARGER THAT ANYOF THE REGIONS?2) WHAT BALANCE BETWEEN MODELING, OBSERVATIONS AND ANALYSIS SHOULD BE USED TO ADDRESS THESE QUESTIONS?3) TO WHAT EXTENT CAN GLOBAL MODELS BE USED TO PROVIDEA GLOBAL FRAMEWORK FOR THE IMS?4) HOW WILL IMS PROVIDE A BRIDGE BETWEEN: - REGIONAL SCALE AND GLOBAL SCALE PROCESSES? - SEASONAL (AND BELOW) TO DECADAL AND CLIMATE CHANGE? - NATURAL PROCESS VS ANTHROPOGENIC PROCESS? - LAND AND OCEAN SPECIALISTS? - OBSERVATIONS AND PREDICTION CAPABILITIES? (E.G., BETTER DATA ASSIMILATION)? - INTEGRATED OBSERVATIONS AND MODELING APPROACHES TO PROCESS UNDERSTANDING? - RESEARCH AND APPLICATIONS?