Hydromagnetic waves in Earth's core and their influence on ...
Hydromagnetic waves in Earth's core and their influence on ...
Hydromagnetic waves in Earth's core and their influence on ...
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
28 Chapter 2 — Space-time analysis(a) SPOTNB H after 320yrs(b) WAVENB H after 320yrs(c) TL plot of SPOTNB H at 10 ◦ S10.80.60.40.20−0.2−0.4−0.6−0.8−110.80.60.40.20−0.2−0.4−0.6−0.8−1(d) TL plot of WAVENB H at 10 ◦ S400140013500.83500.83000.63000.6Time (yrs)2502001501000.40.20−0.2−0.4−0.6Time (yrs)2502001501000.40.20−0.2−0.4−0.650−0.850−0.8−10−150 −120 −90 −60 −30 0 30 60 90 120 150L<strong>on</strong>gitude (degrees east)(e) FK plot of SPOTNB H at 10 ◦ S−10−150 −120 −90 −60 −30 0 30 60 90 120 150L<strong>on</strong>gitude (degrees east)(f) FK plot of WAVENB H at 10 ◦ SFrequency (cycles per year)0.010.0080.0060.0040.0020−10−9 −8 −7 −6 −5 −4 −3 −2 −1 0 1 2 3 4 5 6 7 8 9 10W Z<strong>on</strong>al spatial wavenumber E(g) LAS plot from SPOTNB H8.57.56.55.54.53.52.51.50.50Frequency (cycles per year)0.010.0080.0060.0040.0020−10−9 −8 −7 −6 −5 −4 −3 −2 −1 0 1 2 3 4 5 6 7 8 9 10W Z<strong>on</strong>al spatial wavenumber E42.537.532.527.522.517.512.57.52.50(h) LAS plot from WAVENB H−603−6030−302.5−3025Latitude (degrees)021.5Latitude (degrees)02015−301−3010− 600.5− 605−60 −40 −20 0 20 40 60−60 −40 −20 0 20 40 60Azimuthal Eastward speed z<strong>on</strong>al (km phase −1yr ), positive speed (km(yr) is eastwards−1 )Eastward z<strong>on</strong>al phase −1Azimuthal speed (km yr ), positive speed (km(yr) is eastwards−1 )Figure 2.6: Analysis of H from SPOTNB <str<strong>on</strong>g>and</str<strong>on</strong>g> WAVENB field models.SPOTNB c<strong>on</strong>ta<str<strong>on</strong>g>in</str<strong>on</strong>g>s an isolated drift<str<strong>on</strong>g>in</str<strong>on</strong>g>g field feature <str<strong>on</strong>g>and</str<strong>on</strong>g> WAVENB c<strong>on</strong>ta<str<strong>on</strong>g>in</str<strong>on</strong>g>s a m = 8azimuthally propagat<str<strong>on</strong>g>in</str<strong>on</strong>g>g wave. Plots (a) <str<strong>on</strong>g>and</str<strong>on</strong>g> (b) show H at the <str<strong>on</strong>g>core</str<strong>on</strong>g> surface after320years (these <str<strong>on</strong>g>and</str<strong>on</strong>g> all subsequent snapshots <str<strong>on</strong>g>in</str<strong>on</strong>g> this chapter are <str<strong>on</strong>g>in</str<strong>on</strong>g> Hammer-Aitoff mapprojecti<strong>on</strong>), (c) <str<strong>on</strong>g>and</str<strong>on</strong>g> (d) show time-l<strong>on</strong>gitude (TL) plots of the evoluti<strong>on</strong> of H at 10 ◦ S<str<strong>on</strong>g>and</str<strong>on</strong>g> (e), (f) the frequency-wavenumber (FK) power spectra |H| 2 at this latitude. (g) <str<strong>on</strong>g>and</str<strong>on</strong>g>(h) show the latitude-azimuthal speed (LAS) power plots of ∫ |H R | 2 dz.
Change language