The limit between the subhumid and semiarid zones is represented by the 500 mm
isohyet. The area situated between 500 and 1000 mm/year presents a subhumid climate, and the climate is humid when it exceeds 1000 mm.
The southward movement of the
isohyets has also resulted in the southward migration of pastoralists into lands formerly occupied by sedentary farmers.
6) considered the Hajar Mountains of the UAE to be more "mesic" than the Ru'us al-Jibal to the north, although this classification does not match the reported pattern of
isohyets in the mountain regions (Boer 1997, Fig.
Land area (Mha) of 4 GRDC agro-ecological zones divided by 500 mm mean annual rainfall (MAR)
isohyet GRDC agro-ecological zone <500 mm MAR >500 mm MAR NSW-Vic.
The Gulf of Mexico can be divided into three broad geographic regions according to the weather patterns: eastern, southern and northwestern, because of the southwest-northeast trending isotherms and
isohyets that trend onshore in the northeast region (Douglas & Englehart 1981).
The Isohyetal method consists of recording the depths of rainfall at the locations of the various rain gauges and plotting
isohyets (lines of equal rainfall) by the same methods used for locating contour lines on topographic maps.
The Kedougou area, which belongs to the Sudan-Guinean climate, is located at 1,200-1,300 mm
isohyets; the area is part of the rainiest Senegalese region.
He mapped centers of diversity using numbers of species in
isohyets. These data are not easily convertible to the Flora Neotropica grid and so have not been included in the analyses here.
In the northern Sahara or Saharo-Sahelian zone, the area between the 4 in (100 mm) and 8 in (200 mm) annual rainfall
isohyets, there are pastures dominated by perennial grasses (Panicum turgidum, Aristida pallida, A.