descend, precipitate, fall, surrender
降 centers on downward movement: descending, falling, or precipitating. The surrender sense extends this as lowering oneself or yielding.
降 combines ⻖ (hill, mound) with 夅, which likely represents two feet descending. Together they suggest coming down a hill or slope.
The left side ⻖ is a hill, and the right side 夅 looks like feet stepping downward. Picture walking down a hill: that is descending.
For コウ, imagine a coat sliding down a hill: coat -> コウ, and the coat descends the slope.
on and after; from ... onward; since
to fall (of rain, snow, ash, etc.); to come down
surrender; capitulation; submission
descent; fall; drop; (atmospheric) depression
to descend (e.g. a mountain); to go down; to come down
leaving the mound; being knocked out
rainfall; precipitation
descent; fall; drop; decline; downturn; subsidence
demotion; relegation; downgrading
surrender
rainfall; rain
speckled with white; salt-and-pepper (pattern, fabric, etc.)
surrender; submission; capitulation
snowfall; snow
to jump down; to leap down; to jump off; to leap off
downpour; pouring rain; heavy rain; pelting rain; cloudburst
getting on and off; embarking and disembarking
getting on and off (a vehicle); boarding and alighting
rainfall; rainy weather; rain
descent (esp. in skiing); sliding down; skiing down
amount of precipitation; precipitation
to rain