Arctic atmospherics require new top, or shirt length adjustments (8,6)

I believe the answer is:

northern lights

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'arctic atmospherics require' is the definition.
I can't tell whether this defines the answer.

'new top or shirt length adjustments' is the wordplay.
'top' suggests taking the first letters.
'adjustments' indicates anagramming the letters (I've seen 'adjustment' mean this (the order of letters is adjusted)).
The initial letter of 'new' is 'n'.
'shirt'+'length'='shirtlength'
'shirtlength' anagrammed gives 'thernlights'.
'n'+'or'+'thernlights'='NORTHERN LIGHTS'

Can you help me to learn more?

(Other definitions for northern lights that I've seen before include "What flickers in the sky" , "Blackpool illuminations?" , "overhead display" , "Celestial phenomenon" , "a must-see for Arctic cruisers?" .)

I've seen this clue in the Sydney Morning Herald.

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