HOAR FROST 白霜

 

One of the first signs of winter is the hoar frost of late autumn. Deriving¹ its name from an Old English word (hoar, meaning “to appear old”), this is the thin, feathery coating of ice that often forms on objects during cool nights with clear skies. The clear skies allow the ground to lose heat more quickly than the surrounding air, and the humidity in the atmosphere condenses and freezes into a solid when it makes contact with surfaces. This frost can occur even when the air a few feet above ground is well above freezing, and usually melts within an hour or two of sunrise.

深秋的白霜（hoar frost）是预示冬天到来的最早预告。它的英文名来源于一个“古老”的英语单词（hoar，意思是“显得古老”）。白霜是一层薄薄的羽毛状冰层，通常在晴朗的寒夜凝结于物体表面。晴天使地面温度比周围空气的温度下降更快，大气中的湿气在与地面接触时凝结成固体。即使地面上几英尺的空气远高于冰点，也会形成这种冰霜，并且通常在日出后一两个小时内融化。

 

FROST FLOWER 霜花

 

Frost flowers (and the related "ice ribbons" and "ice beards") are very thin, spindly, unique formations of ice, seen in late autumn or early winter, when plants are first freezing.

霜花（以及相关的“冰带”和“冰须”）是一种薄而细长、非常独特的冰结构，见于深秋或初冬，植物第一次结冰时。

 

When the water in the plant stem freezes, it expands to the point where the plant splits open along the side, and the frozen water is extruded² from the split. More water is then drawn³ up through the stem from the ground via capillary⁴ action, adding more ice crystals to the frost flower.

当植物茎秆中的水凝结时，会涌到茎秆裂开的地方，冻结的水从裂口中溢出。由于毛细作用，植物的茎从地面吸收更多水分，从而结出更多冰晶的霜花。

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