Almost-necessary conditions for a solar active region to produce a subsequent polar cap absorption event

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100 1 ⊔ ‡aCliver, Edward W.
245 1 0 ‡aAlmost-necessary conditions for a solar active region to produce a subsequent polar cap absorption event / ‡cEdward W. Cliver.
264 ⊔ 1 ‡aHanscom AFB, Massachusetts : ‡bAir Force Geophysics Laboratory, Air Force Systems Command, United States Air Force, ‡c1980.
300 ⊔ ⊔ ‡a20 pages : ‡billustrations ; ‡c28 cm.
336 ⊔ ⊔ ‡atext ‡btxt ‡2rdacontent
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490 0 ⊔ ‡aAFGL-TR ; ‡v80-0151
490 0 ⊔ ‡aAir Force Surveys in Geophysics ; ‡vNo. 425
500 ⊔ ⊔ ‡aADA088882 (from http://www.dtic.mil).
500 ⊔ ⊔ ‡a"17 April 1980."
504 ⊔ ⊔ ‡aIncludes bibliographical references (pages 19-20).
520 ⊔ ⊔ ‡aBetween 1955 and 1976, 133 polar cap absorption (PCA) events with unambigious solar flare associations were observed. Over one-fourth of these events (35/133) originated in solar active regions that had already produced a PCA. More significantly, these 'subsequent' PCA's included 35 percent (26/74) of all the principal greater than or = 2.0 dB) PCA's in this sample. In this paper, we establish quantitative criteria to distinguish between those solar active regions that are likely to produce such subsequent absorption events and those that pose no further threat to high latitude HF or VLF communications. These criteria are based on flare solar disk position and the greater than or = 8800 MHz burst peak flux density.
538 ⊔ ⊔ ‡aMode of access: Internet.
650 ⊔ 7 ‡aSolar flares. ‡2fast ‡0(OCoLC)fst01125063
650 ⊔ 7 ‡aSolar activity. ‡2fast ‡0(OCoLC)fst01124887
650 ⊔ 7 ‡aRadio waves. ‡2fast ‡0(OCoLC)fst01087617
650 ⊔ 7 ‡aRadio ‡xInterference. ‡2fast ‡0(OCoLC)fst01087095
650 ⊔ 7 ‡aIonosphere. ‡2fast ‡0(OCoLC)fst00978677
650 ⊔ 7 ‡aCorrelation (Statistics) ‡2fast ‡0(OCoLC)fst00880312
650 ⊔ 0 ‡aCorrelation (Statistics)
650 ⊔ 0 ‡aRadio waves.
650 ⊔ 0 ‡aRadio ‡xInterference.
650 ⊔ 0 ‡aSolar flares.
650 ⊔ 0 ‡aSolar activity.
650 ⊔ 0 ‡aIonosphere.
710 2 ⊔ ‡aU.S. Air Force Geophysics Laboratory.
730 0 ⊔ ‡aTechnical Report Archive & Image Library (TRAIL)
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DAT 1 ⊔ ‡a20220620060655.0 ‡b2024-04-27T17:32:08Z
DAT 2 ⊔ ‡a2024-04-27T17:30:02Z
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