Online Resources for:
“The midlatitude positive bay and the MPB index of substorm activity”
by
Robert L. McPherron and Xiangning Chu
Department of Earth, Planetary, and Space Sciences
University of California Los Angeles
AddRes1 The drawing shows a perspective view of a modern model of the substorm current wedge (SCW) that utilizes empirical magnetic field lines, sheet currents, a partial ring current (PRC), a symmetric ring current (not shown), and currents induced in the Earth by these currents (Chu et al. 2014)
AddRes2A perspective view of the Region 1 (R-1) and Region 2 (R-2) field-aligned current system with the sun to the lower left in drawing. These solenoidal sheets surround the Polar Regions switching directions at noon and midnight. On the dawn side the R-1 current enters the auroral oval at its poleward edge (upper left in drawing) where it divides some flowing across the polar cap and the rest equatorward in a meridian plane. This Pedersen current returns to space at the poleward edge of the dusk side oval, Yellow lines show the direction of the current in the DP-2 Hall current system. The concentration of Hall current between the sheets at dawn and dusk are the westward and eastward electrojets(Le et al. 2010)
AddRes 3 Table showing identification codes, station names, geographic and magnetic coordinates, and universal time of midnight used to produce the MPB index
Code / Station Name / Geo Lat / Geo Long / Mag Lat / Mag Long / UT MidnMBO / Mbour / 14.38 / 343.03 / 20.10 / 57.50 / 0.29
ASC / Ascension Island / -7.95 / 345.62 / -2.40 / 56.60 / 0.96
KOU / Kourou / 5.10 / 307.30 / 11.90 / 19.50 / 3.51
PST / Port Stanley / -51.70 / 302.11 / -41.70 / 11.50 / 3.86
TRW / Trelew / -43.26 / 294.62 / -33.10 / 5.60 / 4.16
SJG / San Juan / 18.11 / 293.85 / 28.60 / 6.10 / 4.41
HUA / Huancayo / -12.05 / 284.67 / -1.80 / 356.50 / 5.02
FRD / Fredicksburg / 38.20 / 282.63 / 48.40 / 353.38 / 5.08
BSL / Bay St. Louis / 30.35 / 270.36 / 40.10 / 339.80 / 6.05
TEO / Teoloyucan / 19.75 / 260.81 / 28.80 / 330.40 / 6.61
BOU / Boulder / 40.14 / 254.76 / 48.40 / 320.59 / 7.32
TUC / Tucson / 32.18 / 249.27 / 39.90 / 316.00 / 7.70
FRN / Fresno / 37.09 / 240.28 / 43.50 / 305.30 / 8.42
PPT / Pamatai / -17.57 / 210.43 / -15.10 / 285.10 / 9.97
HON / Honolulu / 21.32 / 202.00 / 21.60 / 269.70 / 10.53
EYR / Eyrewell / -43.47 / 172.39 / -50.23 / 256.39 / 11.17
API / Apia / -13.81 / 188.22 / -15.40 / 262.70 / 11.45
GUA / Guam / 13.59 / 144.87 / 5.30 / 215.70 / 14.34
ASP / Alice Spring / -23.76 / 133.88 / -32.90 / 208.20 / 14.86
KAK / Kakioka / 36.23 / 140.18 / 27.40 / 208.80 / 15.05
KNY / Kanoya / 31.42 / 130.88 / 21.90 / 200.80 / 15.58
CNB / Canberra / -35.32 / 149.36 / -42.70 / 226.90 / 16.04
BMT / Beijing Ming Tombs / 40.06 / 116.18 / 30.10 / 187.00 / 16.45
GNA / Gnangara / -31.78 / 115.95 / -41.90 / 188.90 / 16.58
LRM / Learmonth / -22.22 / 114.10 / -32.40 / 186.50 / 16.72
PHU / Phuthuy / 21.03 / 105.95 / 10.80 / 177.90 / 17.02
IRT / Irkutsk / 52.17 / 104.45 / 41.90 / 176.90 / 17.13
GCK / Grocka / 44.30 / 102.30 / 43.30 / 102.40 / 17.24
AAA / Alma-Ata / 43.25 / 76.92 / 34.30 / 152.70 / 18.66
ABG / Alibag / 18.63 / 72.87 / 10.20 / 146.20 / 19.15
AAE / Addis Ababa / 9.02 / 38.77 / 5.30 / 111.80 / 21.42
IZN / Iznik / 40.50 / 29.73 / 37.70 / 109.60 / 21.43
TAM / Tamanrasset / 22.79 / 5.52 / 24.70 / 81.80 / 23.07
EBR / De L’Ebre / 40.82 / 0.49 / 43.20 / 81.30 / 23.38
SPT / San Pablo-Toledo / 39.55 / -4.35 / 42.80 / 76.00 / 23.62
HER / Hermanus / -34.43 / 19.23 / -34.00 / 84.00 / 23.78
AddRes4The X component of the magnetic field at Honolulu (HON) is plotted in panel (a) for a 23-day interval centered on March 3, 2008. The main field and storm time variations have been partially removed by subtracting a smooth spline fit to averages of the midnight field. The X variation is symmetric about local noon. The Y variation shown in panel (b) is antisymmetric. The vertical dashed line on March 3
AddRes5 A map of the calculated Sq variation in the Y component at HON during the year 2008. A maximum in Sq-Y occurs a little after dawn and a minimum occurs in the afternoon. The local time of extrema and their strength are modulated by season.
AddRes6 The figure illustrates how substorm power is determined for a given observatory. Panel (a) shows in blue the Y component at HON on March 3, 2008 with mean removed. The smooth red line is the Sq-Y variation for this day with mean removed. In panel (b) the blue line (deltaY) is the difference between the two traces in panel (a). The red line is the difference signal high pass filtered to remove all variations with period longer than 3 hours. Panel (c) is the amplitude of substorm power estimated from the filtered differences of X and Y components. Peaks in the signal during the night hours are often caused by the substorm current wedge. Vertical dash-dot lines are onsets of the current wedge identified from the MPB index
AddRes7The Sq-X variation at HON shown in 5has been smoothed by a 2-D Fourier filter and shifted in phase to be a function of universal time. Local noon at HON is near the end of the day as shown by vertical dashed white line. Horizontal dotted lines show the times of the equinoxes and solstices.
AddRes8This is a zip file “ESM_2_OnsetLists.zip” containing the following files. Each file contains one of the onset lists used in this paper.
ChuMPB.txt:This is a text file containing 40,562 records in the ChuMPB onset list with each record containing a date/time in the format yyyy-mm-dd/HH:MM:SS.
Matlab© code to read this file follows.
fid = fopen('H:\Datafile\EventLists\MidlatitudePositiveBayOnsets\ChuMPB.txt.txt','r');
A = fscanf(fid,'%4d %*c %2d %*c %2d %*c %2d %*c %2d %*c %2d',[6,inf]);
A = A';
mpbo = datenum(A):
mpbo = sort(mpbo);
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
SMag.txtThis is a text file containing 30, 484 SuperMag SML onsets. The format of the file is
yyyymmddHHMMMLatMLong
19960101201671.2722.45
Matlab© code to read this file follows:
smag = load('H:\Datafile\EventLists\Substorm-AL_Onsets\SMag.txt');
dssm = datenum(smag(:,1),smag(:,2),smag(:,3),smag(:,4),smag(:,5),0
dssm = sort(dssm);
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
MCPMPB.txt:This is a text file containing 56,342 records in the MCPMPB onset list. The file format and Matlab code are
yyyymmddHHMMSS
1981123123420
M = dlmread('H:\Datafile\EventLists\MidlatitudePositiveBayOnsets\MCPMPB.txt',’delimiter’,’\t’)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
mcpmpbons78.txtThis is a text file containing 6,384 records in the mcpmpbons78 list. There is no subsetting by peak area.
The file format is integers separated by tabs read by Matlab code
yyyymmddHHMMSS
1981123123420
M = dlmread('H:\Datafile\EventLists\MidlatitudePositiveBayOnsets\mcpmpbons78.txt',’delimiter’,’\t’)
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
ons78700.txt: This is a text file extracted from mcpbons78 containing onsets where area of pulse peak exceeds 700 nT2.
The file format is integers separated by tabs read by Matlab code
yyyymmddHHMMSS
1981123123420
References
Chu XN, Hsu TS, McPherron RL, Angelopoulos V, Pu ZY, Weygand JJ, Khurana K, Connors M, Kissinger J, Zhang H, Amm O (2014) Development and validation of inversion technique for substorm current wedge using ground magnetic field data. Journal of Geophysical Research-Space Physics 119 (3):1909-1924. doi:10.1002/2013ja019185
Le G, Slavin JA, Strangeway RJ (2010) Space Technology 5 observations of the imbalance of regions 1 and 2 field-aligned currents and its implication to the cross-polar cap Pedersen currents. Journal of Geophysical Research: Space Physics 115 (A7):A07202. doi:10.1029/2009JA014979