Wind Profiler Radar for diagnosis of Wind Profiler Radar for diagnosis of precipitating clouds precipitating clouds

K. Krishna Reddy1, Baio Geng1, Ryuichi Shirooka1, Tomoki Ushiyama1, Hiroyuki Yamada1, Hisayuki Kubota1, Hiroshi Uyeda1,2, Masanori Yoshizaki1

1 Institute of Observational Research for Global Change (IORGC) /

Japan Agency for Marine-Earth Science and Technology (JAMSTEC)1, 2 Hydrospheric and Atmospheric Research Center (HyARC), Nagoya University

Capsule:

Single Wind Profiler Radar capabilities and its application for diagnosis of the vertical structure of the Precipitating clouds.

Background and MotivationThe global atmospheric circulation is sensitive to the vertical distribution of latent heating, which is associated with different types of precipitation and hence it is important to distinguish between convective and stratiform precipitation profiles around various precipitating clouds observed during Meiyu/Baiu season and also around western Pacific Ocean region over Palau.

To understand the mechanism of cloud-precipitation processes and air-sea interactions over the warm water pool, focusing on seasonal and intra-seasonal variations (ISV).

Lack of long-term field experiments over Palau region in the Western Tropical Pacific Ocean . In the vicinity of Palau several tropical depression are developed .

To elucidate the global climate change, focusing on the ENSO (El Nino Southern Oscillation) event around the Western Tropical Pacific

Ding, 1995

Brief introduction to the Observational Facilities

Characterization of Meiyu/Baiu Precipitating clouds observed during IOP-2001 and IOP-2002

Microphysical evidence of the transition between predominant convective/stratiform rainfall associated with intra-seasonal variations (ISV) over Palau

Summary and Conclusions

Outline of the Presentation

Aimeliik Observatory

Wind profiler site

AWS observations

Ocean, Land and Atmosphere Interactions Integrated Research Project (IORGC/JAMSTEC)Ocean, Land and Atmosphere Interactions Integrated Research Project (IORGC/JAMSTEC)

Instruments at Peleliu Observation Site

シーロメータ

ＧＰＳ受信器 マイクロ波放射計

ソーラーパネル

ﾄ ー ﾀ ﾙ ･ ｽ ｶ ｲ ･ ｲ ﾒ ー ｼ ゙ ｬ （ＴＳＩ）

ＡＷＳ

地上気象観測装置

長短波放射計 Potable Radiation Package

Automatic Weather Station

Solar panel

Microwave radiometerGPS receiver

Total sky imager

Ceilometer

JW Disdrometer

November 2000 (AWS, GPS) June 2001 (Ceilometer)

October 2001 (TSI, PRP)

December 2001 (MWR)March 2005 (JW Disdrometer)

Microwave profilingRadiometer (MPR)

Ceilometer

JW Disdrometer

AWS

1290 WP: Vh(z), W(z), Cn2(z) Low Mode: ~30 s, 60 m 0.1 to 2-4 km High Mode: ~ 30 s, 200 m 0.3 to 12 kmRASS: TV ~ 30 s, 60 m 0.1 to 1.5 kmMRR: N(D,z), DSD(z), W(z) 1 min, 100 m 0.1 to 3 kmCeilometer: β(z), Cloud base 1 min, 15 m 0.015 to 7.6 kmMPR: T(z), rv(Z), rc(z), integrated vapor & liquid 1 min, variable,0.1 to 10 kmJW Disdrometer: N(D), DSD 1 min, surface measurementsAWS: T,p,e, Vh, Rain intensity 10 sec, surface measurements

Micro Rain Radar (MRR)

RASS Shield

Wind Profiler (WP) Antenna Assembly

Instrument and measured parameter Δt, Δz, height coverage

Instruments at (Palau) Aimeliik ObservatoryInstruments at (Palau) Aimeliik ObservatoryDoppler Radar

Wind Profiler Radar (WPR)

200 m

60 m

Wind profiler data Accuracy: Wind speed : 1 m/s; Wind Direction : 10 degree Reddy et al. 2004

WPR observe Vertical wind directly.

Horizontal wind profiles in the Troposphere .

Useful for classification of Precipitating cloud systems into Convective, mixed (convection/stratiform) and Stratiform.

Characterization of convective boundary layer evolution.

Air quality measurements

Brief introduction to the Observational Facilities

Characterization of Meiyu/Baiu Precipitating clouds observed during IOP-2001 and IOP-2002

Microphysical evidence of the transition between predominant convective/stratiform rainfall associated with intra-seasonal variations (ISV) over Palau

Summary and Conclusions

Outline of the Presentation

Yangtze River

Observational area

Meiyu/Baiu Front

Data used for the Meiyu/Baiu Precipitation Study:Wind profiler : IOP-2001 04 June – 16 July IOP-2002 11 June – 31 JulyRawinsonde : - do –GMS satellite : - do –

Classification of precipitating cloud using Wind Profiler Radar data

(a)

Convection08:03 LT

Transition08:56 LT

DOPPLER VELOCITY, ms1 DOPPLER VELOCITY, ms1DOPPLER VELOCITY, ms1

Stratiform16:38 LT

Stratiform09:07 LT

Precipitation echo

Turbulence echo

Based on Reddy et al. 2002

Doppler Spectra of the vertical beam observed on 21 June 2002

Down ward UpwardDoppler Velocity, ms1

REFLECTIVITY (SNR), dB

Convection08:03 LT

Transition08:56 LT

Stratiform09:07 LT

Precipitation echo

Turbulence echo

Bright Band

22 June 2001 23 June 2001 24 June 2001 19 June 2002 20 June 2002 21 June 2002

IOP-2001 IOP-2002

Algorithm for Classification of Vertical Structure of the Precipitating Clouds observed by the wind profiler radar

Doppler Velocity, m/s

GMS Satellite, AWS & Wind profiler observation during IOP-2001 and 2002

15 June to 15 July 200115 June to 15 July 2001 15 June to 15 July 200215 June to 15 July 2002

0

5

10

15

20

25

30

15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45

15 June - 15 July 2002

0

5

10

15

20

25

30

15 17 19 21 23 25 27 29 31 33 35 37 39 41 43 45

15 June-15July 2001

Acc

umul

ated

rai

nfal

l, m

m

Total Rain fall over Dongshan 254 mmTotal Rainfall over Donghsan 140 mm

0

60

120

180

240

300

360

420

480

16

6

17

0

17

4

17

8

18

2

18

6

19

0

19

4

Julian Day (2002)

Stratiform

Transition

Convection

0

60

120

180

240

300

360

420

480

16

6

17

0

17

4

17

8

18

2

18

6

19

0

19

4

Julian Day (2001)

Min

ute

s

StratiformTransitionConvection

Pow

er failure

TBB

Meiyu/Baiu period Meiyu/Baiu period

Characteristics of Meiyu/Baiu environmental conditions during the year 2001 and 2002

-1000

0

1000

2000

3000

4000

152 157 162 167 172 177 182 187 192 197 202 207 212

CA

PE

/CIN

(J

/kg

)

CAPE

CIN

-1000

0

1000

2000

3000

4000

152 157 162 167 172 177 182 187 192 197 202 207 212

CAPE

CIN

0

20

40

60

80

152 157 162 167 172 177 182 187 192 197 202 207 212

Julain Day (2001)

Pre

cip

itab

le W

ater

(m

m)

0

20

40

60

80

152 157 162 167 172 177 182 187 192 197 202 207 212

Julain Day (2002)

0

20

40

60

80

100

152 157 162 167 172 177 182 187 192 197 202 207 212

Rel

ati

ve

hu

mid

ity

(%

)

1000 hPa

850 hPa

0

20

40

60

80

100

152 157 162 167 172 177 182 187 192 197 202 207 212

1000 hPa

850hPa

Time-height sections of reflectivities over a Doppler radar.

Diurnal variation

3-4-day periodicity

Stronger precipitation systems

Weaker precipitation systems

Geng et al. 2004

2001 2002

Meiyu period Shorter

(June 18 – June 27)

Longer

(June 18 – July 10)

Rainfall amount Much more

(about 400 mm)

Less

(about 200 mm)

Precipitation system Stronger

(many convective echoes)

Weaker

(many stratiform echoes)

Precipitation variety Diurnal variation About 3-4 day periodicity

CAPE / CIN 935.2/-110.01 376.07/-114.67

Precipitable Water (mm) 50.38 45.18

Relative humidity(%) @850 hPa 71.23 64.17

Difference of Difference of Meiyu/Baiu Period):

Brief introduction to the Observational Facilities

Characterization of Meiyu/Baiu Precipitating clouds observed during IOP-2001 and IOP-2002

Microphysical evidence of the transition between predominant convective/stratiform rainfall associated with intra-seasonal variations (ISV) over Palau

Summary and Conclusions

Outline of the Presentation:

Data-collection at Aimeliik Observatory

Months

DATA USED FOR THE PRESENT :

Westerly and Easterly (monsoon) wind regime over Palau

Criteria :

Westerly Wind Regime: 1. Wind Profiler observations between 1.5 and 2 km Zonal wind < (u) > >5 m/s

2. Korror Radiosonde data at 850 hPa Zonal wind > 5 m/s

Westerly Wind Regime: 1. Wind Profiler observations between 1.5 and 2 km Zonal wind < (u) > >5 m/s

2. Korror Radiosonde data at 850 hPa Zonal wind > 5 m/s

10-days averaged Horizontal winds observed over Palau

2003

2004

Intra-seasonal variation (ISV) of precipitating clouds observed during Westerly Wind regime

Month

Easterly winds westerly winds Easterly winds westerly winds

May 30&31 18-29

June 01-06,15-30 07-14 13-30

July* 01-10 02-18 01, 19-31

August 12-23 01-11,24-31 01-31

Sept.* 10-20 01-10*,21-30 03-14,17-21 01-02,15-16, 22-30

Oct. 02-13 01,14-31 21-31 01-20

Nov. 01-22 25-30 01-13,21-25,29 14-20,26-28,30

         

2003 2004

* 11 -22 July 2002 & 29 Aug. to 16 Sept. 2003 No data because Wind Profiler Radar site electric power failure

E1 W1 E2 W2

E1 W1 E2 W2

147 157 167 177 187

149 157 167 177 187

Zonal Winds and Daily mean diameter (27 May to 09 July 2003)

Julian Day

D

Mea

n D

iam

eter

(m

m)

Vel

ocit

y, (

m/s

)

During the easterly periods had Rain drops with larger diameters since mean weighted diameter is about 0.5 and 1.5 mm, while for the westerly case drops diameter isfrom 0.5 to just 1.0 mm. This is evidenceof a convective feature for easterly regime.

Daily mean Doppler Velocity and Spectral width observed between 27 May and 09 July 2003

E1 W1 E2 W2

E1 W1 E2 W2

E1 W1 E2 W2

147 157 167 177 187 147 157 167 177 187

147 157 167 177 187

Daily mean velocity was more positive for easterly regime and its standard deviation was very high, indicating the presence of strong updrafts

The turbulence was concentrated below the 0 oC isotherm during westerly regimes, but during the easterly regime it exceeded this height due to strong convection , related to the strong up and downdrafts.

In the passage of the cloud systems, during IOP-2001, convective and mixed types of rain systems are pre-dominant whereas during IOP-2002 convective systems embedded within a wide stratiform precipitation were observed.

Differences between the cases in IOP-2001 and in IOP-2002 are mainly due to the difference in the distribution of water vapor and local environmental conditions. Our observational results suggest that large difference in relative humidity and horizontal wind speed apart from the large scale systems disturbances. In IOP-2002, relative humidity and horizontal wind speed in the lower troposphere below about 3 km altitude are about 87 percent and 11 m/s, respectively, which are both smaller than those in IOP-2001.

The observational results also suggest that shallow convective boundary layer, low preciptiable water, lower relative humidity and the weak low level jet contributed to the shorter lifetime and the suppressed development of convective precipitating clouds over Dongshan during IOP-2002 compared with IOP-2001.

ConclusionsConclusions (Meiyu/Baiu Period):

The brief microphysical analysis of convective regimes associated with the ISV showed a large difference in type, size and microphysical processes of hydrometeor growth in each wind regime.

Strong spectral width is due to convective precipitation formation mechanisms (turbulence), allowing particles to rapidly grow by accretion of liquid water, while weak spectral width is due to weak turbulence, which allows ice particles to grow by deposition of vapor water, aggregation and, in a last way, by accretion.

Conclusions Conclusions (ISV associated Precipitating clouds over Palau)(ISV associated Precipitating clouds over Palau)

Meiyu period10 days

2001

2002 Meiyu period23 days

Time-latitude sections of infrared satellite images.

Approach of the first typhoon

T

Three consecutiverainy days

T