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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. Outline. Past Monsoon Experiments ICRP – I ndian C limate R esearch P rogramme
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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
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
Northern India, BoB
6. LASPEX – Land Surface Proc. Ex.
land surface processes in a semi-arid
7. BOBMEX - Bay of Bengal Monsoon Experiment
Bay of Bengal
8. ARMEX - Arabian Sea Monsoon Experiment
Arabian Sea & West Coast of India
9.JASMINE – Joint Air-Sea Monsoon Interaction Expt.
1999 (pre to onset, end)
Equatorial IO & Central BoB
(Conceived, planned & executed by Indian Sci.)
BOBMEX, ARMEX ICRP
CTCZ- Continental Trough Convergence Zone
(2008 – 2010)
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
Indian Climate Research Programme
ICRP Implementation Plan, DST1998
Main Focus: Understanding monsoon variability on timescales ranging from sub-seasonal to inter annual and decadal, and its impact on critical national resources
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
Bay of Bengal Monsoon Experiment (BOBMEX):
Arabian Sea Monsoon Experiment (ARMEX):
Jun-Aug 2002, Mar - June 2003 , April-May 2005
July 26, 2005
Mumbai ~940 mm
BOBMEX – 1998-99
Rapid SST Recovery
(Bhat et al, BAMS, 2001)
Indian Oceanographic Research Vessel
~110 m long
31 Scientists + 65 Crew
OLR, Rainfall (GPCP)
1. Intense Rainfall Events on West Coast
2. Warm pool dynamics
Year : 1998
(Source: NIOT Buoy data)
(ARMEX & BOBMEX)
Differences in the Ocean Mixed Layer
North Bay and Arabian Sea (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
High RH – lower LHF & NLW
Lower RH – High LHF
over different basins
Theory (M-O similarity profile)
Diurnal range : SST <0.2oC; Tair >1oC
Comparison of measured & Monin-Obukhov similarity profiles
(Bhat (2006), GRL)
1. SST<Tair, over a period of a month!
2. Heat lost to water ~ 10-20 W m-2
Absorption by Sea
(Bhat, GRL, 2006)
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
Mean June–September rainfall over
the Indian region south of 30 N
All appear important!
Pre-onset & onset – Hot & dry
Peak monsoon (July-Aug) – Wet & moist
Cloud systems & their propagation
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).
(High concentration of Aerosols)
Enormous Aerosol loading
East – west gradient
Marine – dry
Aerosol – cloud interactions
Monsoon Clouds & Rain
Cloud scales processes?
Science plan being prepared
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
5. Validation sites, ship, etc.
Collaboration with other Asian countries