daytime obstruction markings
Aviation safety term: red or yellow-and-white markings painted on structures over 60 meters tall, as required by Japanese aviation law.
Under aviation law, chimneys taller than 60 meters must be equipped with daytime obstruction markings.
The red and white paint on that steel tower is a daytime obstruction marking.
Aviation obstruction lights used at night, whereas 昼間障害標識 are daytime markings.
Compound of 昼間 (daytime), 障害 (obstruction), and 標識 (marking/sign). A technical term from aviation safety regulations.