Average capacity factor for solar cell is about 25% (night, clouds, seasons, etc).

1000W/m2 * 0.25 => ~250W/m2.

1000W/m^2 is average daily peak irradiance. That number is useful for designing system capacity, but doesn't reflect output throughout the day.

1000W/m2 is at noon at the equator without clouds/haze/dust.

1000W m^2 is actualy closer to high noon at Kansas on a fully clear day (this is equivalent to 2,000 umol/cm^2/s-1) Equatorial solar irradiance is actually higher (closer to 1,050W/m^2) because the equator is just a bit closer to the sun.

>Equatorial solar irradiance is actually higher (closer to 1,050W/m^2) because the equator is just a bit closer to the sun.

No, no, no. Equatorial is higher because the sun is more directly overhead on average than in Kansas.

That's not how the inverse square law works for photon flux density.

Maybe that's the 24-hour average?