平成27年度IUGONET研究集会
第2回「太陽地球環境データ解析に基づく超高層大気の空間・時間変動の解明」
2015年8月17-19日 @ 国立極地研究所

地上・衛星統合解析に基づく
磁気擾乱時の中層大気上部の応答の検証
高エネルギー粒子

Sato et al., [2014]
POES
（低高度）

PANSYレーダー
（地上）

GOES
（静止軌道）#西山尚典1、中村卓司1、佐藤薫2、堤雅基1、江尻省1、冨川喜弘1、田中良昌1、津田卓雄3[1] 国立極地研究所; [2] 東京大学 理学系研究科 地球惑星科学専攻;
1[3] 電気通信大学 情報理工学研究科;

Solar Energy Input
太陽放射（UV, 可視光, 赤外）に加えて、高エネルギー粒子による極域大気へのインパクトが大きい
高度

荷電粒子

電磁波

オーロラ粒子 超高層大気
電離気体
高エネルギー/粒子
粒子

太陽放射
紫外線

100 km

破壊NOx

60 km

O3

中層大気上部
中性気体/流体

中層大気上部における高エネルギー降下粒子がもたらす化学反応は気候学・気候変動の観点においても重要

加熱
観測的検証が圧倒的に遅

加熱
0 km

れている大気結合プロセス
2

Chemical effect on EPPs (1)✓EnergeticParticle Precipitations (EPPs) の中間圏への化学応答
Fig. 3. Altitude versus ionisation rates for monoenergetic beams of protons 1–1000 MeV (left) and electrons 4–4000 keV (right).

ARTICLE −IN PRESS
モデル計算：[Turunen et al., 2009; Randall et al., 2015]of NO using the most representative particle flux andenergy spectra available today. For each model run, wealso perform a control run. We convert the precipitationenergy spectra into ionisation rates as a function ofaltitude as discussed above, and run these through the SIC
model using representative fluxes at 701N, 01E in NH
winter conditions. We are then able to compare theincrease in NOx and electron number density as a result of
the precipitation. The case events studied here are: an
example of high levels of proton precipitation flux as seenin the Halloween storm of October 2003; pulsed auroral
precipitation from Ulich et al. (2000); REP from Gaines
et al. (1995) lasting several hours such as those observed
by balloon experiments (Millan et al., 2002); andrelativistic microbursts from Rodger et al. (2007a).

2of Atmospheric and Solar-Terrestrial
Physics 71 (2009) 1176–1189[Turunen et al., 2009]

cur at about
dusk sector.
se minute–chanism for
ith the caseare used in
ed that thisves (Milland by EMICl., 2007a).
transported
eomagnetic
onal studies
and Bailey,
titudinal as
can only beobbin et al.
ation model
presentativevalues of 2+ively. CMAT
eomagnetic
ic latitudes
O are 301S
etic activity,
poleward ofof Geophysical Research: Space Physics

10.1002/2015JA021196

precipitation
3.1.Fig.
Solarproton
events effects on the ion-chemistry of the atmo[Randallet1. Particleal.,
2015]
sphere.

of relatively
and highthe neutral

The modelled response of the middle atmosphere to a2 Fig. 4 as an example ofsolar
is presented
theproton
excitedevent
nitrogenatoms N(inD) and the ground state of
4 high levels of proton precipitation. The
an nitrogen
event with
N( S) (Rusch et al., 1981; Solomon et al.,protonflux
thenitrogen
GOES-11reacts
spectra.
1982a,b). levels
Almostare
all takenof thefrom
excitedwithElectron
concentrations
shownintheupperpanel
areO2 to form NO, providing a significant pathway to NO
enhancedby The
severalorders ofis converted
magnitudeinto
duringtheproduction.
NO produced
NO2 below
periods
of extreme
forcing.
is directly
dependent#65 kmaltitude invariousThisreactions(see e.g.
Brasseuron
andtheSolomon,ionisation
rateandthus
canbeused
formonitoring
2005, pp. 336–341), but the production of NO2 isthebalanced
magnitudeof the forcing
below
80 km.
The effects
by conversion
back toNO either
in reaction
withof O,
theorSPEs
on 28–31theOctober
2003
andbalance
3–5 November
by photolysis,
outcomeof thisgiving the2003
areeasily
identified
intheupperpanelofthefigure
relative concentrations of NO and NO2. During nighttime,
as whenincreases
numberat reactions
60–100 km
littleinO electron
is available,
and density
the above
arealtitudes,
particularly
on 28 converted
October and
3 2 November.
after sunset.
ineffective,
all NO is rapidly
to NO
Once affectedby proton
forcing,amounts
the concentrations
NO in
The productionof excessof long-livedofNO

Fig. 4. The effect of the Halloween solar proton events on electron
number density and NOx as modelled by SIC at 701N latitude,
01 longitude. The simulated electron number density (log(m!3)), from40 to 120 km altitude, with time is shown in the upper panel, and theconcentration of NOx (log(m!3)) over the same altitude range is shown in
the lower panel. Maximum NOx production occurs at "50 km altitudes.

現状では数値モデルと衛星リモートセンシングにdiurnal variation in electron number density and NOx canよる研究が先行
be seen as part of the normal SZA-driven variability, but
the SPE has little influence on it due to the energy of theprotons.
3.2. Auroral electron precipitation

3

1811

Chemical effect on EPPs (2)✓Energetic Particle Precipitations (EPPs) の中間圏への化学応答−

地上観測：[Daaeet al., 2012]
DAAE ET AL.: EEP EFFECTS ON MESOSPHERIC OZONE−とL21811

地磁気擾乱指数（黒、赤）・地上／衛星観測においては鉛直方向の高度分機能や時間分解能が不十分•
オゾン変動量(%)=> 観測による詳細な物理過程の検証が不可欠
1)エネルギー流入量の評価，
2)物質の鉛直輸送，NO(ppmv)3)温度/風速場変動

ure 3. (a) Black (Red) line is the Dst-index (AE-index) from 15 July to 10 August 2009, blue vertical bar shows stormet. (b) Mesospheric O3 anomalies relative to a 7-day average prior to storm onset. Values are given in percentage of
7-day average. Numbers on the plot highlight O3 depletion at different altitudes and times. (c) Daily NO vmr profiles.

最新の南極大型大気レーダーを活用し、 太陽と中層大気との!5 days and continuing down to 55 km !12 days afterstorm onset, after which the feature is lost.
5] The observed daily NO profiles during the time invested are shown in Figure 3c. The NO abundance increased to[e.g., Garcia and Solomon, 1985; Sheese et al., 2011]. NO wasobserved to move downwards to !60 km, tracking thebehavior of the O3 depletion at the same altitudes. Below
60 km, the NO vmr falls below the instrument sensitivity

領域間結合の観点から研究する
4

Polar Mesosphere Winter Echo✓

Polar Mesosphere Winter Echo (PMWE)−⇥cohkm

Mesosphere echo in the polar regions
during non-summer period[e.g., Ecklund and Balsley, 1981]= 8⌅

Volumereflectivity

2✓Electron density

e2 Ne
2 0 me c2◆2Ne (⇤)

84

3-D power spectral
density of electron
density fluctuation
at the Bragg wave
number (κ)[Tatarski, 1961; Lübken et al., 2006]

Czechowsky et al., [1989]

Refractiveindex

7770631000 Bragg

1400 UTscattering

Turbulent layer
Contributions of electron density toecho power are significant.
−fluctuation

Backscatter echo

Mean occurrence rate is only 2.9 % (Total 447.5 h) [Zeller et al. 2006]•Free electron, as scatterer, is not produced enough around dark mesopause
in polar winter.

•Good correlation to enhancement of electron density in D region due to Solar
Proton Event (SPE) [Kirkwood et al., 2002]
5Coincidence: SPE and PMWE✓

First report on PMWE associated with Solar Proton Event−Quasi simultaneous detection of SPE, PMWE, and CNA (GOES, MST radar@Esrange, Riometer @Abisko)

Kirkwood et al., [2002]
GOESsatellite

10 MeV, 100 MeV
echo power

MSTradar[dB]-3Model [cm ]•ele. density
2.5 days
CNARiometer

Enhancement of electron
density (> 1010 m-3) can beseen behind PMWE.

6PMWE detected by PANSY
060
100-10-20
20
1080
60
10080
60
10080
60
10080

North0θ=10°
East-10-202010θ=10°0South-10-202010θ=10°0West-10-202010θ=10°060
hhmm 0000
2013 May 23-10-200400

0800

local noon↑

1200
UT

1600

2000

Echo
Power [dB]

80 θ=0°

Echo
Power [dB]2010PMWE

EchoPower [dB]

ZenithEchoPower [dB]

100

Echo
Power [dB]

Altitude [km]Altitude [km]Altitude [km]Altitude [km]•Altitude [km]WestSouthEast

North

ZenithPANSY radar beams #1-5

Range resolution: 600 m
Time resolution: almost 4 min.
All echoes in five directions
show almost the samecharacteristics in height andtime, which suggests
isotropic scattering byatmospheric turbulence.

20 km @ 60 km alt.

beam 5West✓beam 3
East0000
May 247

Correlations to SPEs✓

Seasonal variations of daily occurrence rate for PMWE

[Nishiyama et al., 2015]

Occurrence
Zeniths sr MeV)][p/(cmp2B, 2p3B,p4B
rate [%]
2[p/(cm s sr MeV)] Occurrence
rate [%]

p2B, p3B, p4B

Zenith12 1210 10
8 8
6 6
4 4
2 20 0(e) (e)2013
winterin SH
2013
winterin SH

104 104
102 102

PMWE
occurrence rate

27-day27-dayrunningrunningaverageaverage60.0-80.0km
60.0-80.0km
Proton flux @magnetosphere100 100

4.2-8.7 MeV
6.7-14.5 MeV
10-210-2
15-40 MeV
Month
MarMarApr AprMayMayJun JunJul JulAugAugSepSepOct OctNovNov
Month2013
2013✓Two SPEs occurred in May 2013. (6 SPEs March through October 2013)•Good correlation to the most of SPEs or EEPs
8

Two SPEs in May 2015✓

Summary plot for GOES and geomagnetic activity
Start
May 14/1325
May 22/1420

End
PFU (@> 10 MeV)
May 17/1720
41
May 23/0650 1660
X-ray (GOES)

Proton (GOES)

Ele. (GOES)

Dst9SPE: PMWE and CNA✓A case study during SPE on May 23, 2013

X-rayGOES (6.6 Re)

X-ray (GOES)
Energetic Proton
onset of M5 flareProton flux: 0.8-2.5
MeV(NOAA)

2.5-6.9 MeVNOAA (800km)

PMWE(60-80km)> 6.9 MeV

Echo PMWE

Cosmic noise
QDC

CNA peak

CNA

Proton precipitation wasobserved over Syowa.
=> Significant ionization inthe lower mesosphere1) Sudden appearance ofPMWE around 65 km
2) Strong absorption ofcosmic noise (~0.8 dB)
10SPE: POES/MEPED and MF radar
GMAG

POES footprint
AACGM lon.
± 10°
AACGM lat.
± 3°
In this event, ILME also
detected by MF radar due
to reflection in highelectron density at altitude
60-100 km.

800 keV-2.5 MeV

Energetic
Protons by
POES/MEPED

2.5-6.9 MeV> 6.9 MeV

MF radarILME (IsolatedLower MesosphereEcho)

11

Summary✓

まとめにかえて高エネルギー粒子降下による中層大気上部の応答を検証−•

SPEDASを用いた地上観測や衛星観測の統合データ解析•

大型大気レーダーで観測されるPMWE（中間圏エコー）を中層大気上部の電離のプロキシとして注目−

2013年5月23日のSPEに対応するイベントを紹介•

POES/MEPEDで高エネルギープロトンのフラックスの上昇が観測•

同時に非常に強いPMWE @ 60-70kmとCNA（~ 0.8 dB）を検出‣−

降下プロトンによる中層大気上部の異常電離に起因

St. Patrick Day’sや2015年6月22日の磁気嵐に対応するPMWEのエンハンスも確認•

高エネルギー電子（> 100keV）による電離の重要性
12Future Work✓「より多くのデータを統合させた解析」に発展−

PMWE（中間圏の電離領域）の空間分布や時間発展: SuperDARN−

鉛直方向の輸送過程: ライダーやレーダー，衛星リモートセンシング
RRLIDARRRLIDAR(smoothed)

Aura/MLS

13