Question

what is the meaning of 1000 cm rain?

Answer 1

With a rainfall of 1 mm, every square metre receives 1 litre of rain water.

Considering the number is accompanied by a time frame pertaining to a certain location, then this means the given location received 1000 cm of rainfall as measured by a rainfall measuring instrument, a rain gauge in this case.Rainfall is always measured in length units mostly inches ,centimeters. In this case it was 1000 cm of rainfall that was collected in the standard gauge used at that particular station.