Microphysical structure in a mesoscale convective system observed by hydrometeor videosondes (HYVISs)

in Palau in June 2013

NCU SeminarMarch 11, 2014 @ NCU, Taiwan

X-band Polarimetric Doppler Radar at Ngarchelong Site, Palau, Coutesy of Dr. H. Minda

Taro SHINODA1*, Yoshio OHWAKI1, Yuuki USHITA1, Akira ICHINOSE1, Shun HIROSE2,

Takeharu KOUKETSU1, Tadayasu OHIGASHI1, Haruya MINDA1, Hirohiko MASUNAGA1, Biao GENG3,

Ryuichi SHIROOKA3, Kazuhisa TSUBOKI1, Hiroshi UYEDA1

1 HyARC, Nagoya University, 2 Yokohama National University, 3 JAMSTEC

X-band Polarimetric Doppler Radar at Ngarchelong Site, Palau, Coutesy of Dr. H. Minda

Targets of the field observation (PALAU2013)

Formation process of the tropical cyclones (TCs).

How does the initial vortex form and concentrate?

From Houze et al. (2009)

Typhoon

Vortex:D ~ 10 km

Vortex:D ~ 100

㎞

Vortex: D = 300 ~ 500 ㎞

Pressure drop and enhancement of vorticity

Targets of the field observation (PALAU2013)

(1) The top-down hypothesis: 　　　 Ritchie and Holland (1997), Simpson et al. (1997), Bister and Emanuel (1997)

A mesoscale convective vortex (MCV) is formed by heating difference between depositional heating above the melting level (ML)and evaporation cooling below the ML. → To estimate deposition heating, we have to know the ice particle’s properties (shape, size, number concentrations, and mixing ratio) above the ML.

From Houze et al. (2009)

Typhoon

Vortex:D ~ 10 km

Vortex:D ~ 100

㎞

Vortex: D = 300 ~ 500 ㎞

Pressure drop and enhancement of vorticity

Targets of the field observation (PALAU2013)

(2) The bottom-up hypothesis: 　　　 Hendrics et al. (2004), Montgomery et al. (2006)

A cumulonimbus cloud accompanied by positive vorticity (vortical hot tower: VHT) is formed and concentrated into the initial TC center. → We have to detect the vortex structure (horizontal scale, vorticity, vertical depth, and duration time).

VHT

Strategy of the field observation (PALAU2013)

・ We installed 2 Doppler radars to identify 3-dimensional wind field. ・ One was a polarimetric radar to identify particle properties. ・ Direct observation for ice particles using hydrometeor videosondes (HYVISs) was conducted.

From Houze et al. (2009)

HYVIS Observation

Aimeliik site X-band Doppler radar of JAMSTEC Range: 150 km HYVIS launching

Ngarchelong site X-band polarimetric Doppler radar of Nagoya University Range: 60 km

Peleliu site: AWS

Framework of PALAU2013 (from May 30 to July 1, 2013)

The Philippines

Preparation of HYVIS observation (before launching)

HYVIS launching

Launching HYVIS at the Aimeliik Site, Courtesy of Mr. Murakami (GODI)

Formation of TCs around Palau in June 2013

T1303 (Yagi) T1304 (Leepi)

T1306 (Rumbia)

★ ★

★

Palau Palau

Palau

Longitude-time section of IR1-TBB (2.5-12.5N)

Courtesy of Dr. H. Yamada

June 06

June 15

June 26

Westward propagating MCSspass over Palau

Time series of echo area (Ngarchelong radar)

June 06 June 15 June 26

・ Echo area (at 2 km, 5 km) is greater during the passage of the westward propagating MCSs (June 6, June 15, and June 26).・ Diurnal variation of echo area is clearly seen (Max: 00-06 LST).

Height: 2 kmHeight: 5 kmHeight: 8 km

May 28 July 1

Time-series of echo-top height (Ngarchelong radar)

■ 　 15 dBZ■ 　 30 dBZ

・ Maximum echo-top height of 15 (30) dBZ is 16 (5-8) km. ・ Low echo-top height of 30 dBZ corresponds to the oceanic convective cells. ・ No clear difference on echo-top height even during the passage of the westward propagating MCSs.

June 06 June 15 June 26

May 28 July 1

MCS observed on June 15, 2013 (JAMSTEC Aimeliik radar)

16 ： 01 LST

Time series of Zh over the Aimeliik (HYVIS launching) site

Convective region

Trailing stratiform region

Transition region

June 15, 2013

A melgint level: 4.8 ～ 5.0 km

From volume scan data of the Ngarchelong radar

Particle images obtained by HYVIS (1430 LST, June 15 launching)

June 15, 2013

1445 LST, 6.1 km, -5.2℃

1449 LST, 7.1 km, -9.9℃

1455 LST, 8.6 km, -19.0℃

1.3 mm

Polarimetric parameters (1444 LST on June 15, RHI: az = 226 deg.)

Zh: 18.3 dBZ ZDR: -0.05 dB

KDP: 0.63°/kmρhv: 0.983

1445 LST, 6.1 km, -5.2℃

Polarimetric parameters (1448 LST on June 15, RHI: az = 232 deg.)

1449 LST, 7.1 km, -9.9℃Zh: 16.8 dBZ ZDR: 0.30 dB

KDP: 1.39°/kmρhv: 0.984

Temperature and humidity profiles of HYVIS observation (1430 LST, June 15)

Temperature and humidity profiles of HYVIS observation (1430 LST, June 15)

1445 LST, 6.1 km, -5.2℃

1449 LST, 7.1 km, -9.9℃

1455 LST, 8.6 km, -19.0℃

Kobayashi diagram: Formation of ice crystals (Kobayashi 1961)

Kobayashi diagram: Formation of ice crystals (Kobayashi 1961)1445 LST, 6.1 km, -5.2℃

Kobayashi diagram: Formation of ice crystals (Kobayashi 1961)1449 LST, 7.1 km, -9.9℃

Kobayashi diagram: Formation of ice crystals (Kobayashi 1961)1455 LST, 8.6 km, -19.0℃

Particle images obtained by HYVIS (1544 LST, June 15 launching)

June 15, 2013

1602 LST, 5.0 km

1609 LST, 6.2 km

Particle images obtained by HYVIS (1705 LST, June 15 launching)

June 15, 20131734 LST, 8.2 km

1725 LST, 5.5 km

Particle images obtained by HYVIS (1824 LST, June 15 launching)

June 15, 2013June 15, 2013

1851 LST, 9.9 km

1845 LST, 7.5 km

Observed particle numbers of each type at each level (H1, H2, H3)

SCW Column Column-with- plates Plate(km) H1 H2 H3 (km) H1 H2 H3 (km) H1 H2 H3 (km) H1 H2 H312.0 0 0 0 12.0 0 0 0 12.0 1 0 0 12.0 1 0 011.6 0 0 0 11.6 0 0 0 11.6 1 0 0 11.6 0 0 011.2 0 0 0 11.2 1 0 0 11.2 1 0 0 11.2 1 0 010.8 0 0 0 10.8 0 0 0 10.8 1 0 0 10.8 1 0 110.4 0 0 0 10.4 1 0 0 10.4 1 0 0 10.4 3 0 010.0 0 0 0 10.0 0 0 0 10.0 4 0 0 10.0 8 0 09.6 0 0 0 9.6 0 0 0 9.6 0 0 0 9.6 7 0 09.2 0 0 0 9.2 2 0 0 9.2 4 0 0 9.2 15 1 18.8 0 0 0 8.8 0 0 0 8.8 7 1 0 8.8 15 0 08.4 0 0 0 8.4 4 0 0 8.4 7 0 0 8.4 28 0 18.0 0 0 0 8.0 5 0 0 8.0 7 0 0 8.0 27 2 07.6 0 0 0 7.6 16 1 0 7.6 1 3 0 7.6 7 1 17.2 0 0 0 7.2 30 0 0 7.2 1 1 0 7.2 3 2 16.8 1 0 0 6.8 35 2 0 6.8 1 2 0 6.8 4 3 16.4 3 0 0 6.4 23 6 0 6.4 0 1 0 6.4 3 6 36.0 62 0 0 6.0 0 6 0 6.0 1 0 0 6.0 1 4 05.6 35 1 0 5.6 0 4 0 5.6 0 0 0 5.6 1 1 25.2 98 4 0 5.2 0 1 1 5.2 0 0 0 5.2 0 0 04.8 29 39 2 4.8 0 1 0 4.8 0 0 0 4.8 0 0 0

合計 228 44 2 合計 117 21 1 合計 38 8 0 合計 125 20 11

Observed particle numbers of each type at each level (H1, H2, H3)

Transportation of particles from convective to stratiform regions

・ If we suppose that ice particles are formed in the convective region, the temperature ranges on the formation of ice particles correspond to those shown in the Kobayashi diagram.

Transportation of particles from convective to stratiform regions

・ The ice particles are presumed to be mainly formed in the convective region according to the temperature range and transported into the stratiform region with gravitational sedimentation.

Summary

・ We were carried out a field experiment in Palau in June 2013 (PALAU2013) using a X-band polarimetric Doppler radar, X-band Doppler radar, and HYVISs in order to reveal the structure of MCS involving vortices as seeds of TCs.

・ We can obtain 3 cases on MCSs that develop TCs after the passage of our observation range FORTUNATELY!!

・ If we suppose that ice particles are formed in the convective region, the temperature ranges on the formation of ice particles correspond to those shown in the Kobayashi diagram.

・ The second and third HYVISs launched into the stratiform region showed decrease of the top height of detection for each particle type, except for the plate type ice particles in the third HYVIS.

→ The ice particles are presumed to transported into the stratiform region with gravitational sedimentation.

Launching HYVIS at the Aimeliik Site, Courtesy of Mr. Murakami (GODI)

Thank you for you kind attention!

Reflectivity and Doppler velocity (0000 LST, June 6)

Toward

Away from

Reflectivity and Doppler velocity (0000 LST, June 6)

Toward

Away from

パラオレーダ観測概要

MP レーダ

ドップラーレーダHYVIS

反射強度場とドップラー速度場（ 6 月 9 日 00 時 00 分：渦？）

近付く

遠ざかる

反射強度場とドップラー速度場（ 6 月 28 日 00 時 00 分：鉛直シア）

近付く

遠ざかる

反射強度場とドップラー速度場（融解層付近での問題点）

HYVIS 観測実施状況（ 1/2 ）No.

Day Time Name Notice

01 6/5 15:32 milkyway T1303 の種02 6/6 09:27 marinelake T1303 の種03 6/6 10:33 naturalarch T1303 の種04 6/6 13:05 zerofighter T1303 の種05 6/9 10:50 fantasy 雲粒子をほとんど取得できず。06 6/9 11:53 softcoral 対流性降水域、融解層以下液相粒子を取得07 6/9 15:12 whale 降水システム08 6/15 14:30 jellyfish T1304 の種、線状降水帯の対流域09 6/15 15:44 inoki T1304 の種、地上降水の強い層状域10 6/15 17:05 ngermeaus T1304 の種、地上降水の弱い層状域11 6/15 18:24 omekangisland T1304 の種、地上降水のほぼ無いアンビル

域

No.

Day Time Name Notice

12 6/21 13:23 bomberyeah 強制吸引型、 CloudSat 通過に合わせて13 6/23 17:47 giantbaba 強制吸引型、 CFH と結合放球14 6/26 10:13 ojisan T1306 の種15 6/26 12:31 ngemelis T1306 の種16 6/26 15:31 ulongisland T1306 の種17 6/26 17:45 seventyisland T1306 の種18 6/28 17:26 palaulemon 強制吸引型19 6/29 ？ ？ 強制吸引型

HYVIS 観測実施状況（ 2/2 ）

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気温・相対湿度の鉛直プロファイルと HYVIS 画像（ 6 月 26 日 10時 13 分）

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Courtesy of Mr. Y. Ohwaki

Time series of Zh in a precipitation system (June 15)