Complex sentence: In the southern hemisphere northings decrease southward from the equator to about metres at 80 degrees South, the south end of the UTM zones; the northing at the equator is set at meters so no point has a negative northing value.
Split into simpler sentences: In the southern hemisphere northings decrease southward from the equator to about meters at 80 degrees South, the south end of the UTM zones. The northing at the equator is set at meters so no point has a negative northing value.