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A Coordinated Field Experiment on Severe Thunderstorm Observations and Regional
Modeling over the SAARC Region
SAARCSAARC
SomeshwarSomeshwar DasDas**
SAARC STORM
SAARC Meteorological Research Centre, SAARC Meteorological Research Centre, Dhaka, BangladeshDhaka, Bangladesh
**Permanent Affiliation: Permanent Affiliation: National Centre for Medium Range Weather Forecasting, National Centre for Medium Range Weather Forecasting,
NOIDANOIDA--Delhi, IndiaDelhi, India
South Asian Association for Regional Cooperation (SAARC)
SAARC Meteorological Research Centre (SMRC)
Dhaka, BangladeshDhaka, Bangladesh
SMRCSMRC
OUTLINE
IntroductionThunderstorm ClimatologySTORM ProgrammeSummary of pilot experiments 2006, 2007 & 2009Coordinated Field Experiment over E & NE India, Bangladesh, Nepal & Bhutan
Part - 1 SAARCSAARC
Part - 2Simulations of Thunderstorms over Bangladesh
Composite characteristics based on Radar, TRMM & WRF Model
Conclusions
Nor’wester/ Squall line of 3 May 2009SAARCSAARC
Source:Source:DWRDWRKolkataKolkata
SAARCSAARC
Nor’wester/ Squall line of 11 May 2009
Thunderstorm Climatology
Socio-Economic Impact of Severe Thunderstorm (Kal Baisaki)
• Severity of NORWESTERS: next to Tropical Cyclones • Average frequency of occurrence:
Kalbaisaki is 28 (±5) in pre-monsoon period Tropical Cyclones (2) (±1)
• Hail Storms and Squall Winds:Loss of human life and animals; Extensive damage to standing crops and property
• Highest lightning-associated casualty in the world.
• Highest frequency of hail storms in the world.
• Frequency of occurrence is second highest to that in the central regions of United States.
• May lead to flash floods
• Major aviation hazard; with several reported air plane accidents.
• Most Tornadoes in the country are associated with Kal Baisaki
Typical damages by a Severe Thunderstorm: 22nd April 2003, Dhubri,Assam.
•Number of affected Villages : 6
•Population Affected : 4900
•No. of human lives lost : 35
• No. of persons with serious injuries : 150
• No. of persons with minor injuries : 1350
• No. of cattle head lost : 517
• No. of poultry lost : 1340
• No. of houses fully damaged : 1350
• No of houses partially damaged : 650
•Total estimated damage :Rs. 2.00 Crore*National Disaster Management Cell (MHA, Govt. of India)
SAARCSAARC
Monthly Frequency of Tornado occurrence in Indian Subcontinent (1839-1999)
02
8
25
14
2 14 4 4
0 00
5
10
15
20
25
30
Jan Feb Mar Apr May June Jul Aug Sep Oct Nov Dec
months
Total : 64
SAARCSAARC
Diurnal variation of Hail storms in India
Monthly distribution of Hail storms in India
SAARCSAARC
STORM Programme
A Comprehensive Observational and Modeling study on genesis, evolution and life cycle of intense tropical convective Storms
What is STORM Programme?SAARCSAARC
STORM-ObjectivesTo understand: genesis, development and propagation of severe thunderstorms
To enhance the knowledge: Dynamical and thermodynamical structure role of microphysical processes for intensification
To study behavior of atmospheric electrification during intensification process and interaction with cloud microphysical processes
Development of meso-scale prediction system with improved forecast skill
SAARCSAARC
SAARC STORM: ROAD MAP
International Programme Committee (IPC)
Phase-1:2009-2011 Nor’westers
India, Bangladesh, Nepal, Bhutan
Phase-2: 2011-2013Deep, Moist & Dry StormsIndia, Pakistan, Afghanistan
Phase-3: 2013-2015Maritime & Continental StormsIndia, Sri Lanka, Maldives
Field Experiment& Implementation
Seven Working Groups
Weather Advisory & Program Management Database Management Capacity Building
& Coordination
Observational Analysis& Parameterization of
Physical Processes
Mesoscale Data Assimilation & Modeling
Cloud Microphysics &Atmospheric Electricity
SAARCSAARC
Mile Stones1. STORM programme originated in India in 2005
2. April-May 2006: 1st Pilot Field Experiment conducted in west Bengal
3. April-May 2007: 2nd Pilot Field Experiment conducted in west Bengal & NE India
4. Nov 2008 : The 14th GB of SMRC approved the STORM project.5. February 2009 : The SAARC Standing Committee, Programme
Committee, and the Council of Ministers endorsed the project.
6. March 2009: The International Programme committee (IPC) constituted.
7. April 2009: The 1st IPC meeting held at IMD, Delhi. The IPC recommended renaming the project as SAARC STORM
7. May 2009: A Pilot field experiment conducted in coordinated way jointly with India, Bangladesh, Bhutan, and Nepal focusing Nor’westers during 1-31 May.
SAARCSAARC
Pilot Experiment, 2006
Pilot Experiment (20°N-27°N, 86°-90°E), 2006Scale Environment of STORM
Synoptic Scale Environment and mesoscale; SAARCSAARC
Outer and Inner Meso - Net Quadrangles
Kolkata
Asnsol
Bhubaneswar
Patna
Guwahati
Murshidabad
Digha
Ranchi
SAARCSAARC
Pilot Experiment, 2007
North-Eastern Sector
Eastern Sector
Map depicting Outer and Inner Meso-Net Quadrangles
SAARCSAARC
List of installed locations of AWS in the NER as on 24th February 2007
SAARCSAARC
SAARC STORM Programme
Phase-1: Nor’westers
Participating countries:
India, Bangladesh, Nepal & Bhutan
Coordinated Joint Field ExperimentBangladesh:
Surface obs: 35Pilot Balloon: 10RS/ RW : 3DWR : 3
Bhutan:Surface (Class-1): 21AWS :
IndiaSurface obs: 559Pilot Balloon: 62RS/ RW : 39DWR : 5
NepalSurface (Class-1): 27
AWS : 15
Pilot Field Experiment conducted during 1-31 May 2009
Govt. of India will provide through ISRO
50 AWS 3 GPS Sondes 1 Doppler Radar
To be installed24 AWS & 1 GPS Sonde in Bangladesh16 AWS, 1 GPS Sonde and 1 Doppler Radar in Nepal10 AWS & 1 GPS Sonde in Bhutan
To fill up the Data gap regions during the main Expts.The AWS will be fitted with Satellite telemetry systems
SAARCSAARC
Thank You
Part – 2
Simulations of Thunderstorms over Bangladesh
SAARCSAARC
Bangladesh: 4Bangladesh: 4--5 March 2008 Thunderstorms5 March 2008 Thunderstorms
Source:Source:DWRDWRKolkataKolkata
SAARCSAARC
Bangladesh: 4Bangladesh: 4--5 March 2008 Thunderstorms5 March 2008 Thunderstorms
LittaLitta, IITD, IITD
**DhakaDhaka
**SylhetSylhet
**RangpurRangpur
SAARCSAARC
3
5
3
13
5
1
17
14
4
1
6
1 12
20
3
1 1
7
0
5
10
15
20
25
Bar
isal
Bog
ra
Ctg
_PB
O
Ctg
_MM
O
Com
illa
Cox
'sba
zar
Dhk
_PB
O
Dhk
_MM
O
Ishu
rdi
Khe
pupa
ra
Khu
lna
Mon
gla
Mym
ensi
ngh
Raj
shah
i
Ran
gpur
Sat
khira
Saw
ndip
Sye
dpur
Syl
het
Station name
Num
ber o
f Eve
nts
Total number of Events occurred during Pre-monsoon season (March-May) 2008
Total number of events = 108
Distribution of Thunderstorm Events based on Wind Speed & Direction
Tornado>150
Severe Nor’wester121-149Moderate Nor’wester91-120Light Nor’wester61-90Squally Wind41-60Gust Wind30-40TypesWind Speed Km/hr
1 (0.93%)
6 (5.56%)
49 (45.37%)50 (46.29%)
2 (1.85%)
0
10
20
30
40
50
60
Gust Wind SquallyWind
LightNor'wester
ModerateNor'wester
SevereNor'wester
Tornado
Types
Num
ber o
f Eve
nts
(4)NE (9)
(1)(29)
(3)
SE(1)SW
(14)
NW(47)
S
N
EW
A
B
8 May 2008 Time: 1413 UTC Dhaka RADAR
Case No. 2
TRMM Over Pass
2A25
46.8SE12.53.023.638.6Average
41SE193.5154531may
47NE9.53404028may63SE11.55.2104524may47SE101.7254023may68SW14.73.2254522may22SE123.7304521may50NE18.22.5304017may62SE103303508may
58SE8.11.7154005may26SE18.52.5303529april31SE6.23101528april
Speed of Propagation ofThunderstorm (km/h)
Direction of Propagation ofthunderstorm
Depth of the cloud(km)
What level was Maxm
(km)
Maxm
intensity of rainfall
vertically (mm/h)
Maxm
intensity of rainfall
horizontally (mm/h)
Date(11 cases)
0
5
10
15
20
25
05_2
155
08_1
413
17_9
10
21_8
44
22_1
421
23_6
53
24_1
230
28_3
53
30_1
012
31_2
44
Date (Time,UTC)
Hei
ght (
km)
0
5
10
15
20
25
30
35
40
45
50
Max
. Rai
n ra
te l
(mm
/h)
Echo base Echo top Max rain rate
02
46
810
1214
1618
20
28/4
/200
8
29/4
/200
8
5/5/
08
8/5/
08
17/5
/200
8
21/5
/200
8
22/5
/200
8
23/5
/200
8
24/5
/200
8
28/5
/200
8
31/5
/200
8
Date
Hei
ght i
n km
Cloud Depth Max intensity
.
0
10
20
30
40
50
60
70
80
0 90 180 270
Propagation Direction (degree)
Prop
agat
ion
Spee
d (k
m/h
)
180/S
0/N
90/E270/WSESE
Composite Characteristics
610NALiquid water content (mg/m3)11.0.36NADowndrafts speed (max) m/s10.2.33NAUpdrafts speed (max) m/s9.
271.39186.27Length of Squall line (Km)8.7.120Maximum wind speed at surface (m/s)7.
48.747.78Speed of movement Km/hr)6.263293Direction of movement (0)5.
26.4629.67Precipitation rate at Surface (mm/hr)4.107.8321.25Intensity of Core pptn. (mm/hr)3.7.313.55Altitude of Core pptn. (km)2.15.1913.14Cloud Top Altitude (Km)1.
ModelObservationSl.No.
ConclusionNone of the convective parameters can be taken as a standalone predictor for the occurrence of thunderstorms with 100% accuracy. Nor’westers propagate like parallel bow shaped squall lines having horizontal length more than 200 km Model underestimated the strength of the squall lines in general.Presence of strong vertical wind shear and, advection of warm air formed solenoidal fields during the Nor’westers.Low level positive vorticity in combination with moist southerly wind from the Bay of Bengal and strong surface heating resulted in the formations of the Nor’westers.Cloud tops reached as high as 18-20 km during the severe storms. Altitude of core precipitation was located between 3-6 km. Average cloud hydrometeor contents of the Norwesters was estimated to be 740 mg m-3.
Thank You