Shantou Tropic of Cancer Sign Tower-Northern Banner to See the Sun

汕头北回归线标志塔-北标窥日

拆件设计

disassembly design

装饰灯

decorative lamp

Scale overview:

The Shantou Tropic of Cancer sign tower is located on Jilong Mountain in Shan Tou City. The sign tower is 13.6 meters high and 30 meters wide at the bottom. It consists of three parts: a base, pillars and a model of the earth. The base of the sign tower is in the Temple of Heaven style and is divided into three floors. The first and second floors are each 1.33 meters high and are each divided into nine steps. The top floor is 0.30 meters high. Only one step is connected to the platform. The platform is paved with granite slabs and is paved from east to west. A black line is laid with black marble to symbolize the Tropic of Cancer. The platform fence is one meter high, and the tower covers an area of more than 200 square meters.

The pillars of the sign tower are two "north"-shaped load-bearing cement supports, supported by reinforced concrete columns and inlaid with polished white marble slices. It is 8.60 meters high, and no matter which direction you look at, it has an obvious character "North", highlighting the theme of the Tropic of Cancer. The earth model is on the upper part of the sign tower, supported by pillars, and has a diameter of 5 meters. The sphere is a reinforced concrete structure. The sphere is pasted with glass mosaics of various colors of yellow, blue and white. The sphere plots the outline of the world. Among them, the territory of China is very conspicuous, with clear land and sea. The center of the sphere vertically runs through a stainless seamless steel pipe with a diameter of 40 centimeters and a length of 5 meters, allowing you to look up into the blue sky. There is a 24-centimeter diameter stainless steel tube in the equatorial Tropic of Capricorn and the polar circle, pointing to the zenith, perpendicular to the ground plane, and running through the surface of the earth model for testing direct sunlight at noon on the summer solstice.

Natural phenomena:

Connecting the sun directly at the northernmost point to form an imaginary line is called the Tropic of Cancer. The vertical point of sunlight moves between the Tropic of Cancer and the Tropic of Cancer throughout the year. Every year at around 12 o'clock on the summer solstice on June 22, there is a moment when the Tropic of Cancer shines directly on the Tropic of Cancer. You can see the circular shadow of sunlight on the ground through the small hole in the middle of the globe. Only once a year can you see the astronomical phenomenon of "standing on the pole without seeing a shadow". A few minutes later, times passed and things changed. Since then, the sun gradually moved south. The invisible Tropic of Cancer is painted tangible on the ground. If your feet cross the Tropic of Cancer, you will have one foot in the temperate zone and one foot in the subtropical zone.

规模概貌 ：

汕头北回归线标志塔坐落在汕头市鸡笼山上。标志塔高13.6米，底宽30米，由基座、支柱和地球模型三部分组成。标志塔基座为天坛式，分三层，第一、二层，各高1.33米，各分九级台阶，顶层高0.30米，只一级台阶连接平台，平台铺上花岗岩石板，并从东向西用黑色大理石铺设一道黑线象征着北回归线。平台围栏高一米，塔位占地面积200多平方米。

标志塔支柱为两个“北”字型承重水泥支架，以钢筋混凝土柱为依托，镶上磨光的汉白玉石片。高8.60米，不论从那个方向望，均呈明显的"北"字，突出北回归线主题。地球模型在标志塔的上部，由支柱支撑，直径5米，球体是钢筋混凝土结构，球面贴上黄、蓝、白各种颜色的玻璃马赛克，球面标绘世界轮廓图，其中中国版图十分显眼，海陆分明，球心垂直贯穿直径40厘米长5米的不锈无缝钢管，可仰窥蓝天。赤道南北回归线和南北极圈，中有一直径24厘米的不锈钢管，指向天顶，垂直地平面，贯穿地球模型表面，作夏至日正午检验太阳直射用。 

自然现象：

把太阳光直射在最北面的点连成一条假想线，就叫北回归线。一年之中太阳光的垂直照射点就在北回归线到南回归线之间移动。每年6月22日夏至日正午12点左右，有一瞬的时间直射北回归线，可看到阳光从地球仪中间的小孔，映在地面上的圆影。每年也只有一次能看到“立竿不见影”的天文现象。几分钟后时过境迁。自此日光逐渐南迁。地面上将无形的北回归线画为有形。脚跨回归线，则一脚在温带，一脚在亚热带。