EVOLUTION OF ATMOSPHERIC

THERMAL STRUCTURE

DURING 2003 MONSOON ONSET

G. S. Bhat, L. Prashanth Rao and Vinayak BhatIndian Institute of Science, Bangalore

National Workshop onArabian Sea Monsoon Experiment

(ARMEX)Data Analysis & Modelling

19-21 April, 2006

Acknowledgements: DST, DOD (NCAOR), IMD, Fellow Scientists & Ship Crew,

1. Vertical thermal structure of the Atmosphere

2. Inter-comparison of Vaisala & NCEP data

3. Average characteristics of T, RH & q profiles

over the Indian Ocean

70 72 74 76 78 80 82longitude (E)

10

13

16

19

latit

ude

(N)

Kochi

Goa

20 25 30 35 40 45 500

10

20

30

40

rain

(m

m/d

ay)

04 09 14 19May June

20 25 30 35 40 45 50

1002

1004

1006

1008

1010

1012

pres

sure

(h

Pa)

04 09 14 19

Daily average pressure and rainfall during May-June (SK193)

Holt & Raman, MONEX-79, BLM, 1987)

Temp.Anmly

20 25 30 35 40 45 500

10203040

rain

04 09 14 19May June

NCEP Under estimates the inversion strength

RHAnmly

20 25 30 35 40 45 500

10203040

rain

04 09 14 19May June

Humidity rapidly built up in 8 daysABL - less moist in NCEP

Wind Speed

Wind Direction

15 20 25 30 35 40 45 500

60

120

180

240

300

360

deg

04 09 14 19May June

wind direction

15 20 25 30 35 40 45 500

5

10

15

m/s

04 09 14 19

wind speed

SK193:

0 10 20 30 40

wind speed (m/s)

1000

900

800

700

600

500

400

300

200

100

0

pres

sure

(m

b)

6/6, 11306/6, 14306/6, 17307/6, 05307/6, 11307/6, 1730

Upper Winds

-80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30

temperature (deg. C)

1000

900

800

700

600

500

400

300

200

100

0

pres

sure

(m

b)

6/6, 11306/6, 14306/6, 17307/6, 05307/6, 11307/6, 1730

-80 -70 -60 -50 -40 -30 -20 -10 0 10 20 30

temperature (deg. C)

1000

900

800

700

600

500

400

300

200

100

0

pres

sure

(m

b)

20032002

Some Remarks:

1. Strong diurnal variation in clouding & rainfall( at least 8 Satellite Images /day)

2. Cloud shape over the AS during 2003 monsoon- long cloud bands, not seen in 2002.

3. Over AS - what dictates convection?

4. AWSs working fine at all 4 stations, however, had serious problems at Vengurla:

- set alright- added soil temperature & solar radiation

Fate of these AWS?

Need for a datalogger that can store 12 months data

2 AWSs given to IAF - letter from DSTminutes of PAMC

Clouds : Rolls?

BOBMEX - Jul-Agu 99

ARMEX:1 : Jun-Aug 20022 : Mar-Jun 2003

IRSP4: Mar 2001

SOC : Jan-Feb 2004

longitude (E)

latit

ude

65 70 75 80 85 90-5

0

5

10

15

20

25

BoB

ArabianSea

INDIA

Goa

MUM

Radiosonde positions

Observations1. Mean2. Standard Deviation

Models/Indirect1. Sounders on Satellites2. Numerical Models

Deg. C

heig

ht(

km)

-90 -60 -30 0 300

5

10

15

20

ARMEX2aARMEX2bIRSP4SOCBOBMEXARMEX1

Temperature

Average (Tropical) Soundings in the Indian Ocean

Deg. C

heig

ht(

km)

0 1 2 3 4 50

5

10

15

20

ARMEX2aARMEX2bIRSP4SOCBOBMEXARMEX1

Temperature Variance

longitude (E)

lati

tud

e

65 70 75 80 85 90-5

0

5

10

15

20

25

BoB

ArabianSea

INDIA

Goa

MUM

Lowest 15 km : T variance <2oC

%

heig

ht(

km)

0 20 40 60 80 1000

5

10

15

20

ARMEX2aARMEX2bIRSP4SOCBOBMEXARMEX1

Relative humidity

longitude (E)

latit

ude

65 70 75 80 85 90-5

0

5

10

15

20

25

BoB

ArabianSea

INDIA

Goa

MUM

%

heig

ht(

km)

0 20 400

5

10

15

20

ARMEX2aARMEX2bIRSP4SOCBOBMEXARMEX1

Relative humidity Variance

longitude (E)

lati

tud

e

65 70 75 80 85 90-5

0

5

10

15

20

25

BoB

ArabianSea

INDIA

Goa

MUM

RH variance maximum in mid-troposphere

g/kg

heig

ht(

km)

0 5 10 15 200

5

10

15

ARMEX2aARMEX2bIRSP4SOCBOBMEXARMEX1

Average mixing Ratio

longitude (E)

lati

tud

e

65 70 75 80 85 90-5

0

5

10

15

20

25

BoB

ArabianSea

INDIA

Goa

MUM

g/kg

heig

ht(

km)

0 1 2 3 4 50

5

10

15

ARMEX2aARMEX2bIRSP4SOCBOBMEXARMEX1

Mixing Ratio Variance

longitude (E)

lati

tud

e

65 70 75 80 85 90-5

0

5

10

15

20

25

BoB

ArabianSea

INDIA

Goa

MUM

Maximum mixing ratio variance: ~1-2 km (inversion3-4 km

Integrated Water Vapour

NIO: MONSOON

Spring

days

kg/m

**2

0 10 20 30 40 50 6010

20

30

40

50

60

70

bbxarmex1sk193irsp4socsk190 spring