Latitudinal and longitudinal behavior of the geomagnetic field during a disturbed period: A case study using wavelet techniques

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• 作者：Virginia Klausner^a ; ¹ ; ² ; ^{virginia@univap.br" class="auth_mail" title="E-mail the corresponding author} ; Margarete Oliveira Domingues^b ; ^{mo.domingues@lac.inpe.br" class="auth_mail" title="E-mail the corresponding author} ; Odim Mendes Jr.^c ; ^{odim@dge.inpe.br" class="auth_mail" title="E-mail the corresponding author} ; Aracy Mendes da Costa^c ; ^{aracy@dge.inpe.br" class="auth_mail" title="E-mail the corresponding author} ; Andres Reinaldo Rodriguez Papa^d ; ³ ; ^{papa@on.br" class="auth_mail" title="E-mail the corresponding author} ; Arian Ojeda Gonzalez^a ; ^{arian@univap.br" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Energy injection ; October 18&ndash ; 22 ; 1998 geomagnetic storm ; Vassouras observatory ; Wavelet techniques
• 刊名：Advances in Space Research
• 出版年：2016
• 出版时间：15 November 2016
• 年：2016
• 卷：58
• 期：10
• 页码：2148-2163
• 全文大小：3640 K

文摘

Coronal mass ejections are the primary cause of the highly disturbed conditions observed in the magnetosphere. Momentum and energy from the solar wind are transferred to the Earth’s magnetosphere mainly via magnetic reconnection which produces open field lines connecting the Earth magnetic field to the solar wind. Magnetospheric currents are coupled to the ionosphere through field-aligned currents. This particular characteristic of the magnetosphere–ionosphere interconnection is discussed here on the basis of the energy transfer from high (auroral currents) to low-latitudes (ring current). The objective of this work is to examine how the conditions during a magnetic storm can affect the global space and time configuration of the ring current, and, how these processes can affect the region of the South Atlantic Magnetic Anomaly. The H- or X-components of the Earth’s magnetic field were examined using a set of six magnetometers approximately aligned around the geographic longitude at about class="mathmlsrc">title="View the MathML source" class="mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0273117716000569&_mathId=si13.gif&_user=111111111&_pii=S0273117716000569&_rdoc=1&_issn=02731177&md5=6fe43374bfb491c4d83742f745dbaaa2">class="imgLazyJSB inlineImage" height="16" width="65" alt="View the MathML source" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0273117716000569-si13.gif">class="mathContainer hidden">class="mathCode">$10°\text{,}140°$ and class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0273117716000569&_mathId=si14.gif&_user=111111111&_pii=S0273117716000569&_rdoc=1&_issn=02731177&md5=43a589ee5fdca4e5730baf1eb44501dc" title="Click to view the MathML source">295°class="mathContainer hidden">class="mathCode">$295°$ from latitudes of class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0273117716000569&_mathId=si15.gif&_user=111111111&_pii=S0273117716000569&_rdoc=1&_issn=02731177&md5=3a282d9e7ffe1220a99c77c555c48c2f" title="Click to view the MathML source">70°class="mathContainer hidden">class="mathCode">$70°$N to class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0273117716000569&_mathId=si15.gif&_user=111111111&_pii=S0273117716000569&_rdoc=1&_issn=02731177&md5=3a282d9e7ffe1220a99c77c555c48c2f" title="Click to view the MathML source">70°class="mathContainer hidden">class="mathCode">$70°$S and aligned throughout the equatorial region, for the event of October 18–22, 1998. The investigation of simultaneous observations of data measured at different locations makes it possible to determine the effects of the magnetosphere–ionosphere coupling, and, it tries to establish some relationships among them. This work also compares the responses of the aligned magnetic observatories to the responses in the South Atlantic Magnetic Anomaly region. The major contribution of this paper is related to the applied methodology of the discrete wavelet transform. The wavelet coefficients are used as a filter to extract the information in high frequencies of the analyzed magnetogram. They also better represent information about the injections of energy and, consequently, the disturbances of the geomagnetic field measured on the ground. As a result, we present a better way to visualize the correlation between the X- or H-components. In the latitude range from class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0273117716000569&_mathId=si17.gif&_user=111111111&_pii=S0273117716000569&_rdoc=1&_issn=02731177&md5=107248b87d2f4038815fcc5b075c5e36" title="Click to view the MathML source">∼40°class="mathContainer hidden">class="mathCode">$\sim 40°$S to class="mathmlsrc">class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0273117716000569&_mathId=si18.gif&_user=111111111&_pii=S0273117716000569&_rdoc=1&_issn=02731177&md5=a23301faeed484fe48473ec162332e29" title="Click to view the MathML source">∼60°class="mathContainer hidden">class="mathCode">$\sim 60°$N, the wavelet signatures do not show remarkable differences, except for the amplitudes of the wavelet coefficients. The sequence of transient field variations detected at auroral latitudes is probably associated to occurrences of substorms, while at lower latitudes, these variations are associated to the enhancement of the ring current.