• tropics
  • The region of the earth's surface lying between two parallels of latitude on the earth, one 23°27' north of the equator and the other 23°27' south of the equator, representing the points farthest north and south at which the sun can shine directly overhead and constituting the boundaries of the Torrid Zone.
Abstract from DBPedia
    The tropics are the region of Earth surrounding the Equator. They are delimited in latitude by the Tropic of Cancer in the Northern Hemisphere at 23°26′11.2″ (or 23.43644°) N and the Tropic of Capricorn inthe Southern Hemisphere at 23°26′11.2″ (or 23.43644°) S; these latitudes correspond to the axial tilt of the Earth. The tropics are also referred to as the tropical zone and the torrid zone (see geographical zone). The tropics include everywhere on Earth which is a subsolar point (the Sun is directly overhead) at least once during the solar year. Thus the maximum latitudes of the tropics have the same value positive and negative. Likewise, they approximate, due to the earth not being a perfect sphere, the "angle" of the Earth's axial tilt. The "angle" itself is not perfectly fixed due chiefly to the influence of the moon, but the limits of tropics are a geographic convention, being an averaged form, and the variance is very small. In terms of climate, the tropics receive sunlight that is more direct than the rest of Earth and are generally hotter and wetter. The word "tropical" sometimes refers to this sort of climate rather than to the geographical zone. The tropical zone includes deserts and snow-capped mountains, which are not tropical in the climatic sense. The tropics are distinguished from the other climatic and biomatic regions of Earth, which are the middle latitudes and the polar regions on either side of the equatorial zone. The tropics constitute 40% of Earth's surface area and contain 36% of Earth's landmass. As of 2014, the region was home to 40% of the world's population, and this figure was then projected to reach 50% by 2050.

    熱帯(ねったい)とは、地球上で緯度が低く年中温暖な地域のことである。緯度による定義、気候区分による定義が存在する。 緯度による定義では、赤道を中心に北回帰線(北緯23度26分22秒)と南回帰線(南緯23度26分22秒)に挟まれた帯状の地域を意味する。英語で熱帯を意味するtropicsは、回帰線(tropic)から生まれた言葉である。 気候区分による定義は気象学者によって複数存在する。以下では気候区分による定義、それもケッペンの気候区分における定義に基づいた内容を紹介する。ケッペンの気候区分における記号はAで、最も低緯度に位置することを示す。 アリソフの気候区分では、1936年に発表された「地理的気候帯」の中に熱帯があり、赤道気候(E)・赤道モンスーン気候(E.M.)・貿易風気候(Pass.)の3つに区分される。さらに貿易風気候は海洋性(Pass. m.)と大陸性(Pass. c.)に分割される。ただし、現在よく知られている1954年発表の気候区分には「熱帯」は存在しない。