manifestation of strong geomagnetic storms in the ionosphere above europe d. buresova(1), j....
TRANSCRIPT
Manifestation of strong geomagnetic storms in the ionosphere above Europe
D. Buresova(1), J. Lastovicka(1),
and G. DeFranceschi(2)
(1) Institute of Atmospheric Physics, Prague, Czech Republic
(2) Instituto Nazionale di Geofisica e Vulcanologia, Roma, Italy
Outlook
A pre-storm enhancement of foF2
Occurrence frequency of positive and negative phases of ionospheric storms
TEC and scintillations at high latitudes
Height profile of storm effect in the F region
Storm effects in the F1 region
Data:Observed and IRI-2001-generated electron density N(h) profiles for 8 European stations for 65 strong (DsT<-100 nT)-to-great (DsT<-350 nT) geomagnetic storms from the period 1995 – 2005;geomagnetic activity indices for analyzed stormy periods.
Data sources: •COST296 Space Weather Database web side :
http://www.ukssdc.ac.uk/wdcc1//wdc_menu.html•Umass Lowell Center of Atmospheric Physics Digital Ionogram Database (DIDBase) •Data from selected European vertical incidence ionospheric stations •IRI web side:
http://modelweb.gsfc.nasa.gov/models/iri.html
List of contributing European vertical incidence ionospheric stations
NAME OF THE
IONOSPHERIC STATION
GEOGRAPHIC LATITUDE AND
LONGITUDE
MAGNETIC LATITUDE AND
LONGITUDE
Tromso 69.70N, 19.0E 67.0N, 117.5E Juliusruh 54.60N, 13.4E 54.3N, 99.7E Chilton 51.6N, 358.7E 54.1N, 83.2E
Pruhonice 50.0N, 14.6E 49.7N, 98.5E Rome 41.9N, 12.5E 42.3N, 93.2E Ebro 40.8N, 0.5E 46.3N, 80.9E
Athens 38.0N, 23.6E 36.4N, 102.5E El Arenosillo 37.1N, 353.2E 41.4N, 72.3E
The existence of magnetic storm and level of storm intensity was defined using Dst index in the following way:
• Strong storm conditions where defined when Dst < -100 nT for at least 4 consecutive hours
• Storms conditions prevail when Dst < -50 nT
18 19 20 21Days
0
3
6
9
12
15
Nm
F2,
105
cm
-3
-120-100
-80-60-40-20
020
DsT
, nT
February, 1999
Juliusruh
- 5 0- 2 5
02 55 0
- 5 0- 2 5
02 55 0
- 5 0- 2 5
02 55 0
fo
F2
, %
- 5 0- 2 5
02 55 0
1 8 1 9 2 0 2 1D a y s
- 5 0- 2 5
02 55 0
J u l i u s r u h
C h i l t o n
P r u h o n i c e
E b r o
E l A r e n o s i l l o
18 19 20 21Days
0
3
6
9
12
15
Nm
F2,
105
cm
-3
-120-100
-80-60-40-20
020
DsT
, nT
February, 1999
Juliusruh
Deviations less than 10% have not been taken into account.
The F region response to storm-induced disturbances is described in terms of deviations of NmF2 from the quiet time median values, i.e. δNmF2.
Different stations provide partly different pattern
15
50
13 14 15 16Days
0
3
6
9
Nm
F2,
105
cm
-5
-150
-100
-50
0
50
Dst
, nT May, 1997
Chilton
28 29 30 31Days
0
3
6
9
12
15
18
Nm
F2,
105
cm
-5
-400
-350
-300
-250
-200
-150
-100
-50
0
Dst
, nT
October, 2003
Chilton
65 storms – 15 with, 50 without a positive enhancement on the day before the storm
Observed (left panel) and IRI-2001generated (right panel) NmF2 over Europe, October 28, 2003 at 12:00UT – positive “quiet” disturbance before the storm – bad IRI-observation agreement
-5 0 5 10 15 20
Longitude
40
45
50
55
60
65
La
titu
de
El Arenosillo
Pruhonice
-5 0 5 10 15 20
Latitude
40
45
50
55
60
65
Lo
ng
itu
de
El Arenosillo
Pruhonice
Observed (left panel) and IRI-2001generated (right panel) NmF2 over Europe, October 29, 2003 at 12:00UT – storm day – better observation-IRI agreement
-5 0 5 10 15 20
Longitude
40
45
50
55
60
65
La
titu
de
Pruhonice
El Arenosillo
-5 0 5 10 15 20
Longitude
40
45
50
55
60
65
La
titu
de
Arenosillo
Pruhonice
12
21
1116
18
11
17
12
20
10
27
145
12 5
2
Appearance of negativephase
Appearance of positivephase
Appearance of both positive and negative phases
Juliusruh
Chilton
El Arenosillo
Summer
W inter
Summer
W inter
Summer
Winter
Summer
Winter
Summer
Winter
Summer
W inter
Summer
W inter
Summer
W inter
Summer
Winter
Appearance of negative and positive phases of 65 ionospheric storms for three European stations
0ctober 30, 2003 event. Maps of TEC (corrected to vertical), S4 index, and phase scintillations between 21-22 UT from all satellites in view. The receiver location is shown with a red cross.
The GISTM System consists of a high rate (50Hz) dual-frequency receiver with special firmware. It is specifically configured to measure and automatically record amplitude and phase of scintillations from the L1 GPS frequency and TEC from the L1 and L2 frequencies.
GISTM receiver at NY ALESUND, 78.9° N, 11.9° E
November 20 2003 event between 20-21UT
Scintillations and TEC as signatures of the high latitude ionospheric response to geomagnetic storms
May 15 2005 event between 11-12 UT
Some details at poster by Aquino et al. on scintillation monitoring (Wednesday)
20-11-2003, 20-21 UT 30-10-2003, 21-22 UT
15-05-2005, 11-12 UT
TEC, Phase and Amplitude scintillations at NyAlesund for three strong events as a function of latitude of the subionospheric point calculated for the assumed ionospheric altitude 350 km.
Amplitude and phase scintillations seem to be associated with the increase in TEC, a characteristics of the edge of a polar-cap patch.
From Mitchell at al., GRL, 2005
Geomagnetic storms of November 1998 and August 2000
August 8 - 15, 2000
-250
-200
-150
-100
-50
0
50
8 9 10 11 12 13 14 15Days
Ho
url
y D
st,
nT
min. Dst (-237) nT
November 11 - 18, 1998
-250
-200
-150
-100
-50
0
50
11 12 13 14 15 16 17 18Days
Ho
url
y D
st,
nT
min.Dst (-133) nT
El Arenosillo Chilton
11/11 11/12 11/13 11/14 11/15 11/16 11/17 11/18
Days
048
12162024
Nm
F2
, 105
(cm
-3)
El Arenosillo Chilton
08/08 08/09 08/10 08/11 08/12 08/13 08/14 08/15
Days
0369
121518
Nm
F2
, 105
(cm
-3)
November 1998 geomagnetic storm Changes in midday electron density at different F region heights (the difference between mean Ne of the pre-storm quiet days and mean Ne during the geomagnetic storm main phase)
Chilton (51.5N, 358.7E)
160km170km
180km190km
200km210km
220km230km
NmF2
-7.5 -5 -2.5 0 2.5 5 7.5
Ebro (40.8N, 0.5E)
160km170km180km190km200km210km
220km230km
NmF2
-7.5 -5.0 -2.5 0.0 2.5 5.0 7.5
Pruhonice (50.0N, 14.6E)
160km170km
180km190km
200km210km
220km230km
NmF2
-7.5 -5.0 -2.5 0.0 2.5 5.0 7.5
Arenosillo (37.1N, 353.2E)
160km170km
180km190km200km210km
220km230km
NmF2
-7.5 -5.0 -2.5 0.0 2.5 5.0 7.5
Comparison of changes in the midday electron density at different ionospheric altitudes during main phases of
August 2000 and November 1998 geomagnetic storms
Chilton 1998.11.13
160km
180km190km
200km210km
170km
NmF2230km220km
Arenosillo 2000.8.12160km170km180km190km200km
210km220km
NmF2
-7,5 -5 -2,5 0 2,5 5N, 105 cm-3
Chilton 2000.8.12
160km170km180km190km200km210km220km
NmF2
Arenosillo 1998.11.13
160km170km
180km190km200km210km
220km230km
NmF2
-7,5 -5,0 -2,5 0,0 2,5 5,0N, 105 cm-3
Geomagnetic storms effect penetration into F1 regionData for 36 strong geomagnetic storms (Dst <-100 nT) and super storms (Dst <-300 nT) from 1995 to 2002.
• The main physical mechanism controlling the F1 region response to geomagnetic storm is change in ion composition, which is related to the neutral composition (O, O2, N2 ) seasonal and storm time variation.
• Chilton (190 km) – light blue – much stronger storm effects in winter and autumn (winter half of the year)0
0.5
1
1.5
0
0.5
1
1.5
Win
ter
Sp
rin
g
Su
mm
er
Au
tum
n
Win
ter
Sp
rin
g
Su
mm
er
Au
tum
n
Chilton (annual course) 190 km
Ebro (annual course) 190 km
2345
6789
1/1 7/1 12/31
109 c
m-3
O
N2
Geomagnetic storms effect penetration into F1 region
Differences between the midday mean Ne of the pre-storm quiet days Ne of the storm main phase and.
Pruhonice (winter storms)
16
0 k
m
16
0 k
m 17
0 k
m
17
0 k
m
18
0 k
m
18
0 k
m
19
0 k
m
19
0 k
m0
0.5
1
1.5
2
2.5
Ne
, 10
5 cm
-3
Ebro (winter storms)
16
0 k
m
16
0 k
m
17
0 k
m
17
0 k
m
18
0 k
m
18
0 k
m
19
0 k
m
19
0 k
m
0
0.5
1
1.5
2
2.5
Ne
, 10
5 cm
-3
Pruhonice (summer storms)
160
km
160
km
170
km
170
km 180
km
180
km 190
km
190
km
0
0.5
1
1.5
2
2.5
Ne,
10
5 c
m-3
The effects of superstorms (full columns) are larger and penetrate deeper than the effects of strong storms
Conclusions
In spite of many years of investigations of effects of geomagnetic storms on the F region ionosphere, there are still many open questions, like the pre-storm enhancements of foF2, storm effects on the bottomside F region (they are relatively well known and understood in the F2-region maximum), or model (IRI) reproducibility of the observed geomagnetic storm-related effects. We are able to predict appearance of ionospheric storms based on geomagnetic storm predictions, but we cannot predict reliably phase (positive or negative) of the storm.
Some references:Buresova, D.: Effects of geomagnetic storms on the bottomside
ionospheric F region, Adv. Space Res., 35, 429-439, 2005.Buresova, D., Lj. R. Cander, A. Vernon, and B. Zolesi: Effectiveness of
the IRI-2001-predicted N(h) profiles updating with real-time measurements under intense geomagnetic storm conditions over Europe, Adv. Space Res., 2005 (accepted).
Buresova, D., Lastovicka, J., Altadill, D., and Miro, G.: Daytime electron density at the F1 region in Europe during geomagnetic storms, Ann. Geophysicae, 20, 1007-1021, 2002.
Lastovicka, J.: Monitoring and forecasting of ionospheric space weather – effects of geomagnetic storms. J. Atmos. Solar-Terr. Phys., 63, 697-705, 2002.
Mikhailov, A.V., Schlegel, K.: Geomagnetic storm effects at F1-layer heights from incoherent scatter observations, Ann. Geophysicae, 21, 583-596, 2003.
Mitchell, C N, L Alfonsi, G De Franceschi, M Lester, V Romano and A W Wernik, GPS TEC and Scintillation Measurements from the Polar Ionosphere during the October 2003 Storm, Geophys. Res. Lett., 32, L12S03, doi: 10.1029/20