Wavenumber 4 in vertical ExB drift

1. Possible mechanism for generating changes in wave number 1 and wave number 4 in vertical ExB drift (compare w. and w/o ECMWF simulations) Status: 11 January 2013 Based on the timegcm run with daily ECMWF and GSWM02 tides Consequence: Possible replacement of figure 7 and 9 of the draft paper with Figure 7: focus on PW1 at high latitude Figure 9: might need two panels one for 70-80 km DE3+PW1-> DE2 110 km DE3+DE2->PW1 First examine what mechanism is taking place?

2. Wavenumber 4 in vertical ExB drift DE3 is decreased in E-region in the simulation with PW1 at the LB. Examine mechanism PW1+DE3->DE2 + DE4 Why is DE3 weak at 110 km? Maybe around 80 km DE3 interacts with PW1 and generate a DE2, and in E-region DE2 and DE3 generate a PW1? Old plot

3. Look at DE2, DE3, and PW1 around 80 km • Plot between 60-90 km (the last two pages are summary plots over time) • UnAmp_PW1DE3DE2_time_latH_line_sswpaper.ps • Compare to w/oECMWF • UnAmp_PW1DE3DE2_60_90Km_daily_woEcmwf.ps • w. ECMWF: DE3 and PW1 generate a DE2 around 70-80 km, DE2 is small at 80 km, grows with altitude then in E-region larger; DE3 looses momentum due to interaction. DE2 in case w. ECMWF is more asymmetric about the geog. Equator. Higher DE2 amplitudes in NH which also has the strong PW1 compared to the case w/o ECMWF. DE3 in case w. ECMWF has a smaller amplitude than in the case w/o ECMWF due to nonlinear interaction of DE3 with PW1 at 70-80 km it looses momentum. Temporal variability of DE2 and DE3 in the case w. ECMWF (line plot) is highly correlated (last two plots).

4. Are DE2 and DE3 generating a PW1 in the E-region? • Plot between 60-140 km (Note: irr. Height!) • UnAmp_PW1DE3DE2_time_latH_line_sswpaper_Eregion.ps • Compare to w/o ECMWF • UnAmp_PW1DE3DE2_60_140Km_daily_woEcmwf.ps • This could be a possible mechanism. The PW1 from the mesosphere does not seem to be connected to the one in the E-region (s. height-time plot at the end of the file) – at least not that it is only a propagating component into the E-region. • In the case w/o ECMWF the PW1 at the geog. Equator has the same temporal evolution as DE3 and DE2 (since climatology the temporal variation is changing in the middle of the months- linear interpolation between months). This temporal variation can not be explained by the offset of the geomagnetic equator which will also generate a PW1 at geog. Equator (PW1 amplitude around 15 m/s quite large). Same mechanism takes place in case w. ECMWF. Since temporal variation of DE2 and DE3 has higher temporal variability, PW1 at geog. Equator has also higher temporal variations. • Note about latitudinal variation of PW1 in E-region in case w/o ECMWF (last plot): Close to the south pole the two bands of higher PW1 amplitude are along the geomagnetic south pole which is approx. at -75 deg. Geog. Latitude. Higher amplitude at geographic equator of PW1 is generated by offset of geomagnetic and geog. Equator, and in addition I think from DE2 and DE3 nonlinear interactions (see PW1 peak around doy 15). There are two additional bands of higher amplitude around -40 and 55 deg geog. Latitude. This could be generated from the nonlinear interaction between SW2 and SW1. In the case w/o ECMWF SW1 in the polar region is generated by the offset of the geomagnetic pole (check with Mack’s paper). Since the geog. Latitudes of these bands are different in the two hemispheres this supports that it might be caused by a geomagnetic effect.

5. The PW1 around 45 deg and 90 km could be generated by the interaction between SW1 and SW2 • UnAmp_PW1SW1SW2_time_latH_line_sswpaper_Eregion_SW.ps • Compare to w/o ECMWF • UnAmp_PW1SW1SW2_60_140km_latH_daily_all_woEcmwf.ps • (this file includes very high and mid-latitude summary plots) • In the case w. ECMWF (doy-height plot) SW2 amplitude is getting weaker between DOY 15 and 27 around 110 km; SW1 has stronger signal between DOY 15 and 27 around 110 km; PW1 amplitude is getting larger between DOY 13 and 27 around 110 km. It is possible that SW1 and SW2 generate the PW1 around 50 deg geog. Latitude and 100-110 km. • In the case w/o ECMWF: PW1 at mid-latitude has smaller amplitudes than w. ECMWF (~22 m/s compared to 50 m/s); PW1 temporal signature agrees with one from SW1, either both are generated by offset of geomagnetic pole (however lat. Plot does not suggest there is a connection from pole to mid-latitudes), or PW1 around 50 deg geog. Latitude is generated by SW2 and SW1 interaction. It might be both. A signal of Kp variation can be seen in high latitude PW1 and SW1. • SW1 could be generated at very high latitude through PW1 and SW2 interaction • (in the following plots only the last two pages are different) • UnAmp_PW1SW1SW2_time_latH_line_sswpaper_Eregion_SW_2.ps • (these plots have a lat-time plot of the different component included, and can be compres to lat-time plot w/o ECMWF) • UnAmp_PW1SW1SW2_time_latH_line_sswpaper_Eregion_SW_3.ps • SW1 from case w/o ECMWF is much smaller (~10 m/s) than w. ECMWF (~ 50 m/s) so offset of geomagnetic pole cannot be the only cause of SW1. SW1 and PW1 temporal variation at 80 deg lat. Correlate well. SW2 is getting weaker between from DOY 18 when SW1 is getting stronger.

6. Schematic of possible nonlinear interactions

7. New plot with TW3 TW3 in the case w/o ECMWF has larger amplitude in E-region than w. ECWMF. TW3 is generated by nonlinear interaction, especially between DW1 and SW2 since TW3 is not specified at the lower boundary of the model. In the case w.ECMWF SW2 at 110 km and 50 deg lat. Is slightly larger than SW2 w/o ECMWF. However looking at the lat-DOY plot of SW2 with and without ECMWF it can be seen that SW2 w/ECMWF is smaller than w/oECMWF (lat. Structure of SW2 is slightly different). DW1 in the case w. ECMWF shows more temporal variation and the magnitude is smaller than w/oECMWF. TW3 in the case of w.ECMWF shows the temporal signature of SW2, indicating that SW2 and DW1 are generating TW3. TW3,SW2,DW1 plot w. ECMWF Un_TW3SW2DW1_60_140km_latH_daily.ps TW3,SW2,DW1 plot w/o ECMWF Un_TW3SW2DW1_60_140km_latH_daily_woEcmwf.ps

8. Updated plots for paper • Wavenumber 1: • With and w/o ECMWF this shows the effect from ion-neutral coupling at equator in PW1 and at pole the effect of geophysical activity on SW1 and PW1 (look up finding Mack’s paper) • SW1 in polar region generated by nonlinear interaction between SW2 and PW1 in case w.ECMWF. W/o ECMWF PW1 in polar region much smaller than w/ECMWF. • PW1 around 45 deg geog. Latitude might be generated by nonlinear interaction between SW1 and SW2. • PW1 at equator is combination of offset of geomagn. Equator and DE2 and DE3 interaction (temporal variability higher than w/oECMWF)

9. Wavenumber 4: • Indication that DE2 and DE3 interaction generates a PW1 at the equator. In case of w/o ECMWF PW1 show monthly variation of tidal DE2 and DE3 component. There is no reason ion-neutral coupling would generate this. • DE2 is generated around 70-80 km by nonliear interaction between DE3 and PW1 in case wECMWF. PW1 is negligible in w/oECMWF at these height. DE3 looses momentum due to nonlinear interaction, and has smaller amplitude than w/oECMWF. • DE2 and DE3 in E-region might generate PW1 in equatorial region. Similar time variation of PW1 as DE2. see also w/oECMWF case. • DE2 is case wECMWF tends to have maximum amplitude more in northern hemisphere compare to more equator in case w/oECMWF. Therefore PW1 at equator (see plot previous page) w.ECMWF is also more in northern hemisphere compared to case w/oECMWF.

10. Possible C/NOFS contribution Session: Ambient Ionosphere and Thermosphere (including electrodynamics) The Earth’s ionosphere and thermosphere are subject to significant variations as a function of solar activity, geographic location, altitude, local magnetic field geometry, and forcing from below. This session will discuss the variation and variability of the ambient ionosphere and thermosphere as well as that of geophysical drivers, including solar effects, geomagnetic activity, electrodynamics, thermal properties, and tidal effects. SSW 2006 event Changes in tides with and without planetary wave activity (what I have so far, could be basis) Increased variability in vertical ExB drift (have runs, needs to look at existing plots, JRO, MH etc stations), also look at average Changes in SSW response with increase F10.7 number (ionosphere, electric field – need to check if this run can be used from beginning of 2011) Magnetic perturbation (have Josuke run, but also increase f10.7 run) Need to focus: what is interesting for the meeting, and with what topic could I have synergy effect.