what are doldrums, horse latitude nd sobpolar?

Answer 1

The doldrums are the seas near the equatorial trough marked by very light winds but there is often rain.

The horse latitudes are the seas under the sub-tropical ridge. This is about 30° to 40° south and north. The air is descending so there is no cloud or rain and the winds are very light. Equatorwards of the ridge are the trade winds.

Sub-polar means high latitudes but usually not south of the Antarctic circle or north of the Arctic circle which are polar regions.