Realtime geomagnetic indices for mid-latitudes. MID-R, MID-E, MID-U and MID-L

Author(s):  
Antonio Guerrero ◽  
Elena Saiz ◽  
Consuelo Cid

<p>Mid latitudes around 40 degree are influenced by effects typically found at both high and low latitudes. Moreover, the focus of the Solar Quiet ionospheric current system, drifts around these mid-latitudes. Consequently they have been considered as a complicated place to infer the geospace state from the ground and also complicated for practical procedures to generate geomagnetic indices. <br>The procedure designed at the University of Alcala specially focused on removing solar regular variations at mid-latitudes is delivering a geomagnetic Local Disturbance index (LDi) in realtime. The same procedure can be used to produce global geomagnetic indices when applied to several geomagnetic stations at these latitudes. <br>We present in this work the high-resolution (one minute) realtime production of ring current and auroral indices (MID-R, MID-E, MID-U and MID-L) similar to the well known Dst and AE indices for mid-latitudes which will help in the understanding of the complex physical processes that emerge at these latitudes. At the same time they fill a gap in the current operational space weather products available for these latitudes.</p>

1999 ◽  
Vol 17 (5) ◽  
pp. 692-706 ◽  
Author(s):  
S. Tsunomura

Abstract. A modeling method is proposed to derive a two-dimensional ionospheric layer conductivity, which is appropriate to obtain a realistic solution of the polar-originating ionospheric current system including equatorial enhancement. The model can be obtained by modifying the conventional, thin shell conductivity model. It is shown that the modification for one of the non-diagonal terms (Σθφ) in the conductivity tensor near the equatorial region is very important; the term influences the profile of the ionospheric electric field around the equator drastically. The proposed model can reproduce well the results representing the observed electric and magnetic field signatures of geomagnetic sudden commencement. The new model is applied to two factors concerning polar-originating ionospheric current systems. First, the latitudinal profile of the DP2 amplitude in the daytime is examined, changing the canceling rate for the dawn-to-dusk electric field by the region 2 field-aligned current. It is shown that the equatorial enhancement would not appear when the ratio of the total amount of the region 2 field-aligned current to that of region 1 exceeds 0.5. Second, the north-south asymmetry of the magnetic fields in the summer solstice condition of the ionospheric conductivity is examined by calculating the global ionospheric current system covering both hemispheres simultaneously. It is shown that the positive relationship between the magnitudes of high latitude magnetic fields and the conductivity is clearly seen if a voltage generator is given as the source, while the relationship is vague or even reversed for a current generator. The new model, based on the International Reference Ionosphere (IRI) model, can be applied to further investigations in the quantitative analysis of the magnetosphere-ionosphere coupling problems.Key words. Ionosphere (electric fields and currents; equatorial ionosphere; ionosphere-magnetosphere interactions)


2002 ◽  
Vol 107 (A2) ◽  
pp. SMP 8-1-SMP 8-12 ◽  
Author(s):  
T. Motoba ◽  
T. Kikuchi ◽  
H. Lühr ◽  
H. Tachihara ◽  
T.-I. Kitamura ◽  
...  

1998 ◽  
Vol 22 (9) ◽  
pp. 1369-1372
Author(s):  
G.T Birk ◽  
U Becker ◽  
J Dreher ◽  
T Neukirch

1997 ◽  
Vol 15 (10) ◽  
pp. 1301-1308 ◽  
Author(s):  
R. G. Rastogi ◽  
D. R. K. Rao ◽  
S. Alex ◽  
B. M. Pathan ◽  
T. S. Sastry

Abstract. Changes in the three components of geomagnetic field are reported at the chain of ten geomagnetic observatories in India during an intense solar crochet that occurred at 1311 h 75° EMT on 15 June 1991 and the subsequent sudden commencement (SSC) of geomagnetic storm at 1518 h on 17 June 1991. The solar flare effects (SFE) registered on the magnetograms appear to be an augmentation of the ionospheric current system existing at the start time of the flare. An equatorial enhancement in ΔH due to SFE is observed to be similar in nature to the latitudinal variation of SQ (H) at low latitude. ΔY registered the largest effect at 3.6° dip latitude at the fringe region of the electrojet. ΔZ had positive amplitudes at the equatorial stations and negative at stations north of Hyderabad. The SSC amplitude in the H component is fairly constant with latitude, whereas the Z component again showed larger positive excursions at stations within the electrojet belt. These results are discussed in terms of possible currents of internal and external origin. The changes in the Y field strongly support the idea that meridional current at an equatorial electrojet station flows in the ionospheric dynamo, E.


2012 ◽  
Vol 117 (A3) ◽  
pp. n/a-n/a ◽  
Author(s):  
Y. Yamazaki ◽  
K. Yumoto ◽  
D. McNamara ◽  
T. Hirooka ◽  
T. Uozumi ◽  
...  

Sign in / Sign up

Export Citation Format

Share Document