ICRP Field Experiments G. S. Bhat Centre for Atmospheric & Oceanic Sciences

1. ICRP Field Experiments G. S. Bhat Centre for Atmospheric & Oceanic Sciences Indian Institute of Science Bangalore Celebrating the Monsoon 24-28 July, 2007 Indian Institute of Science, Bangalore

2. Outline • Past Monsoon Experiments • ICRP – Indian Climate Research Programme • ICRP Field Experiments • Completed: BOBMEX, ARMEX • Planned - CTCZ

3. Monsoon Experiments • IIOE – International Indian Ocean Expedition • 1960 – 1965 • multinational,20 countries • 40 ships, aircraft (drop-sonde), etc. • 2. ISMEX - Indian Summer Monsoon Experiment • 1973 • Indo-Soviet • 6 research ships (4 – USSR, 2 Indian) • Arabian Sea, the equatorial region • and southern Indian Ocean • 3. MONSOON-77 • 1977 • Indo-Soviet • Monsoon Onset, depression, etc. • 4. MONEX-79, Monsoon Experiment (FGGE) • 1979 (summer MONEX) • Multinational • ~20 ships, research air craft

4. Leadership – External Indians – Participated Many benefits to India a. New institutes (e.g., NIO IIOE) b. Infrastructure development c. Man power training d. Data over the Indian region (ocean & land) e. India’s own measurements started (MONEX-79) Impetus to developing national field programmes

5. 5. MONTBLEX- Monsoon Trough BL Experiment 1990 Indian Northern India, BoB 6. LASPEX – Land Surface Proc. Ex. 1997-98 Indian North-Western India land surface processes in a semi-arid area 7. BOBMEX - Bay of Bengal Monsoon Experiment 1999 Indian Bay of Bengal 8. ARMEX - Arabian Sea Monsoon Experiment 2002-2005 Indian Arabian Sea & West Coast of India 9.JASMINE – Joint Air-Sea Monsoon Interaction Expt. 1999 (pre to onset, end) International Equatorial IO & Central BoB

6. Post 1980 Expts. - Indian, except for JASMINE (Conceived, planned & executed by Indian Sci.) BOBMEX, ARMEX  ICRP Next CTCZ- Continental Trough Convergence Zone (2008 – 2010)

7. ICRP - Genesis Early 1990s :- Indian Scientists (a) What we know about Indian Monsoon? (b) What needs to be understood? Action plan to address outstanding problems utilizing limited national resources Science Plan Indian Climate Research Programme (DST 1996) ICRP Implementation Plan, DST1998

9. ICRP Main Focus: Understanding monsoon variability on timescales ranging from sub-seasonal to inter annual and decadal, and its impact on critical national resources • Observational • Modeling • Data Analysis • Inter-Agency & Multi-Institutional • Department of Science & Technology (Lead) • Department of Ocean Development • Department of Space • India Meteorology Department(MoES) • Ministry of Defence • Research Institutes • Universities

10. maximum impact from the limited resources available in the country, a road map formonsoon research in the country for the coming decade with well focused programmes • Observational • Modeling • Data Analysis • Field Experiments : 2 Executed + 1 planned • Focus: Indian Region • Strategy in Field Expts. • Science objectives • Test the hypothesis or • Find answers to a burning question • Implementation Plan - Used all available national resources

11. ICRPExperiments Bay of Bengal Monsoon Experiment (BOBMEX): 1998-1999 Arabian Sea Monsoon Experiment (ARMEX): Jun-Aug 2002, Mar - June 2003 , April-May 2005 1998 July 26, 2005 Mumbai ~940 mm BOBMEX – 1998-99 Air-sea Coupling Rapid SST Recovery Northward Propagation North-South gradients (Bhat et al, BAMS, 2001) • ARMEX – 2002-2003, 2005 • Intense Rainfall Events on WC • Warm pool build up & Collapse • Monsoon Onset over Kerala • Mausam Jan. 2005 (Special Issue)

12. ORV Sagar Kanya Indian Oceanographic Research Vessel ~110 m long 31 Scientists + 65 Crew

13. North Bay SST- maintenance OLR, Rainfall (GPCP) (shaded) (cont.) June-Sept.: 1978-95 • Maximum Precipitation • Region of highest clouding in the entire region • Cloud systems - Cut off solar radiation • Wind speed generally increases • SST decreases • How SST is maintained above the • threshold level (28oC) • Top fresh water layer – shallow mixed layer • (solar penetration, Debasis, et al. • GRL, 2002)

14. ARMEX : 1. Intense Rainfall Events on West Coast 2. Warm pool dynamics Year : 1998 (Source: NIOT Buoy data)

15. Temp salinity Density (ARMEX & BOBMEX) Differences in the Ocean Mixed Layer North Bay and Arabian Sea (AS)

16. Rainfall & SST CAPE

17. Differences in the surface energy balance over Bay & AS (weak phase of convection/ break monsoon) Net heat flux:- Bay: 140-180 W/m2; AS:- ~zero! IO (JASMINE) ~ 80Wm-2. WP(TOGA-COARE) ~80 Wm-2 Bay – Positive feedback between ocean & atmosphere AS - Low precipitation, stronger winds, atmos.inversion

18. BAY weak winds High RH – lower LHF & NLW AS Winds stronger Lower RH – High LHF

19. Wind speed dependence of latent heat flux over different basins

20. ARMEX – 2002 : Temperature inversion at air-sea interface Theory (M-O similarity profile) measurement Diurnal range : SST <0.2oC; Tair >1oC Comparison of measured & Monin-Obukhov similarity profiles (Bhat (2006), GRL)

21. SST Ta Buoy data (WHOI,1995 ) 1. SST<Tair, over a period of a month! 2. Heat lost to water ~ 10-20 W m-2

22. SST Ta (WHOI) Absorption by Sea salt particles (Bhat, GRL, 2006) Hydrodynamic instability

23. Hydrodynamic instability Wind shear & stable stratification (Kelvin-Helmholtz) Wave breaking takes place – strong low level jet can account for up to 30 W/m2 of heat flux under the conditions prevailing over the Arabian Sea Atmos. Ocean

24. CTCZ BriefBackground

25. Monsoon Zone Mean June–September rainfall over the Indian region south of 30 N

26. Too many issues to address All appear important!

27. Observations – Rainfall results from Propagation • of monsoon systems • Models - unable to simulate this propagation • in the monsoon zone • Monsoon rainfall simulation - Poor • CTCZ - ? • Can we understand the mechanism of • propagation in nature? • Better prediction of Monsoon rainfall

28. Dynamic surface conditions May Jul Jun Aug Pre-onset & onset – Hot & dry Peak monsoon (July-Aug) – Wet & moist Cloud systems & their propagation

29. Land-surface processes – complex terrain & varying vegetation Land-atmosphere coupling strength diagnostic for boreal summer (the difference,dimensionless, describing the impact of soil moisture on precipitation), averaged across the 12 models participating in GLACE (after Koster et al 2004,2006).

30. Aerosols & cloud microphysics (High concentration of Aerosols) Enormous Aerosol loading East – west gradient Marine – dry Aerosol – cloud interactions

31. Clouds are important Monsoon  Clouds & Rain Cloud scales processes? Cloud microphysics?

32. CTCZ • Coupled Land-Ocean-Biosphere-Atmosphere Experiment • Modulation of monsoon by land hydrological processes • Cloud scale processes • Aerosols & cloud microphysics • Multi-year programme Planning Stage Science plan being prepared • Pilot : 2008 • Main : 2009-10

33. Super sites

34. Global Teleconnections

35. Some positive developments: Indian 1.IMD’s expansion plans – network of AWSs, DWRs, high resolution radiosondes, raingauge network, satellites, 2. IITM – Cloud Seeding Expt - Research aircraft 3. STORM Project – Infracture 4. Megha-Tropiques 5. Validation sites, ship, etc.

36. Weather knows no national boundaries Collaboration with other Asian countries AMY08, MAHASRI YOTC

37. Thank you