Why do ~GEO sats seem to cluster around the top portion and bottom portion of the belt, 180 degrees apart?

Question

I made a 3D tle model from https://www.space-track.org/ API. I drew a dashed blue line to show the really "geo" orbits that hardly move with time (ECEF). Then there are a bunch of sats that move up and down and around that are not stuck in the geo plane.

My question is, why do they seem to cluster around the top portion and bottom potion of the belt, 180 degrees apart? Highlighted with the purple arrows. If you go forward a whole day, it almost looks like a spinning disc of satellites that are not strictly on the geo belt. There is also a 24 hour periodicity the up and down clusters follow.

I would assume the sats would be in a sort of random distribution, but there looks like a pattern. I'm curious if this is intentional with their launch, like to follow the sun, or it is from some physics.

I am also not a astro person but I do have an ok understanding of fundamental physics/math.

https://satellitevisualization.pythonanywhere.com/

This is the API parameters that created the model: https://www.space-track.org/basicspacedata/query/class/gp/EPOCH/%3Enow-30/MEAN_MOTION/0.79--1.21/ECCENTRICITY/%3C0.21/OBJECT_TYPE/payload/orderby/NORAD_CAT_ID,EPOCH/format/3le

See answers to: Why is the ribbon of decommissioned geosynchronous satellites skewed? and links therein. Also see this answer to How stable are satellites in a graveyard orbit and links therein. You don't mention your selection criteria for "~GEO" and how tightly you set your "24 hour" window. Satellites that are really in GEO will have a period of almost exactly one sidereal day (23h 56m 04s) and those moved to "graveyard orbits" at end of life will have a longer period. — uhoh, Jun 14 '23 at 23:33
If you extract the periods of all the objects you show and plot a histogram, you'll get a sharp peak near 1436 minutes, and a noisy bump about 300 km higher which using Kepler's 3rd law will be roughly 15 minutes longer. (Check me, I'm commenting pre-coffee) Once in the graveyard, station-keeping generally ceases and the orbits become inclined due to the gravitational perturbations primarily of the Sun, making them wobbly up and down (what wobbly looks like (but IN GEO)) — uhoh, Jun 14 '23 at 23:42
@uhoh Good point, this might help show the criteria... It's the API parameters that created the model https://www.space-track.org/basicspacedata/query/class/gp/EPOCH/%3Enow-30/MEAN_MOTION/0.79--1.21/ECCENTRICITY/%3C0.21/OBJECT_TYPE/payload/orderby/NORAD_CAT_ID,EPOCH/format/3le — Krits, Jun 14 '23 at 23:47
more about orbits slightly above GEO (graveyard and not) What was the first spacecraft intentionally placed in a supersynchrous Earth orbit? (period longer than a sidereal day) and What was the first spacecraft intentionally moved from GEO to the graveyard orbit to die? (just a bit above geosynchronous) and Why put SunRISE in the graveyard? Why will it "fly slightly above geosynchronous orbit"? — uhoh, Jun 14 '23 at 23:48
I looked at your first link, and it appears to tackle to question. Thanks All for the links! — Krits, Jun 14 '23 at 23:50
ya /MEAN_MOTION/0.79--1.21 is super wide. GEO will be around 1.003 $$\frac{24 \cdot 60}{23 \cdot 60 + 56}$$ (mean motion is number of orbits per 24 hours) and graveyard is just slightly below 1 — uhoh, Jun 14 '23 at 23:51
@uhoh quick question, if I had checked this on the equinox, it wouldn't be so obvious then? — Krits, Jun 15 '23 at 00:01
I think you can do that experiment yourself, or ask it as a new question. However have a good look at @Puffin's answer first. You also might like the 2nd plot in What is the origin of the ring of debris in inclined GSO orbits? — uhoh, Jun 15 '23 at 00:09
here's the spike at 1436 minutes (note it's log scale) and the wide "blob" ~15 minutes higher https://i.stack.imgur.com/Q7k21.png (from here) — uhoh, Jun 15 '23 at 00:33

Why do ~GEO sats seem to cluster around the top portion and bottom portion of the belt, 180 degrees apart?

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