以前學過的地理名詞

Horse latitudes
馬緯度
約在北緯及南緯 30 度至 35 度海洋上之緯度帶，該處以無風或極輕微之風為主，天氣則熱而乾燥。 此緯度顯示副熱帶高壓軸之正常位置，並隨太陽向南北移動約 5度。兩無風帶即所謂南
北半球之「南回歸線無風帶」(Calms of Capricorn)及「北回歸線無風帶」 (Calms of Cancer), 在北大西洋中即為撒茄索海(Sargasso Sea)之緯度。 此名稱相信源出帆船時代，當橫渡大西洋航行時，在此緯度常因無風或不定風，使船前進至緩，由於缺水，載馬匹至西印度之船隻必須將馬匹投入海中。


南北緯大約30處，由赤道低壓帶上升的氣流，向兩極擴散，逐漸喪失熱量，空氣冷卻收縮，密度增加，於是在南、北緯30度左右，空氣下沈，形成副熱帶高壓帶，此帶風向不定、風力微弱，又稱副熱帶無風帶或馬緯度無風帶，之所以稱為「馬緯度」，那是因為西班牙帆船裝載馬匹至新大陸，到了這裡風力突然減弱，前進困難，由於飼料 欠缺而只好把馬匹拋入海中。
在此帶內，空氣下沈，乾燥少雨，風力微弱，風向不定。所以很少有雲或雨，世界上最大的沙漠也大都 在這一個地區。地面氣壓頗高，下層空氣乃分向赤道(信風帶)及兩極流動(西風帶)。

Horse latitudes
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This article refers to the geographical area. See also Horse latitudes (disambiguation)

A diagram showing the relative positions of the Horse lattitudes
Horse latitudes or Subtropical High are subtropical latitudes between 30 and 35 degrees both north and south, characterized by light winds and hot, dry weather, caused by descending air. The belt in the Northern Hemisphere is sometimes called the “calms of Cancer” and in the Southern Hemisphere it is called the “calms of Capricorn”. The phrase's etymology is uncertain. The ancient Persian navigator and general Sataspes whose very name derived from his command of a Persian horse cavlary unit (sat was the unit size and asp(es) was the Persian word for horse) has been credited by some historians as the founder of the term. Sataspes was the leading explorer and navigator of this day, circumnavigating Africa as well as mapping out the Cape of Good Hope and Cape Verde. Those navigating ancient waters probably referred to those latitudes as the ones Sataspes mapped out, and in ancient times the term was interchangeable for "horse". The term also has probably survived from ships traveling to the New World that were often stranded in this region and forced to slaughter or jettison onboard horses in order to lighten the load, preserve precious water supplies, or for their meat and blood, but this may be apocryphal.
The warm, dry conditions of the horse latitudes also relate to the existence of temperate deserts, such as the Sahara Desert in Africa, the southwestern United States and northern Mexico, and parts of the Middle East in the Northern Hemisphere, and the Chilean-Argentinian-Peruvian desert, the Kalahari Desert, and the Australian Desert in the Southern Hemisphere.