冰风暴成因 Ice Storm Causes

一篇对话气候专家的采访，采访中讨论了冰风暴的成因，还涉及到了其它科学小知识。 An interview with a weather expert discussing the causes of ice storms and other scientific information.

*这是煦日节前在《水晶日报•周末版》上的采访*

*This is an interview published on the Crystal Daily — Weekend Edition before the Solwarm Festival.*

「万峰水晶中」——你真的了解冰风暴吗？

Among the Crystal Peaks: Do You Really Know About Ice Storms?

上一周，贝洛伯格气象中心发布了冰风暴橙色预警信号，受北方涅咯莎外强烈冷锋入侵，上层区中心及近郊遭到了冰风暴天气的猛烈袭击。这次短暂的冻雨给贝洛伯格带来了名叫「雨凇」的景观，许多建筑、树枝上都形成了长长的冰挂。

Last week, the Belobog Meteorological Center issued a code orange ice storm warning. Invaded by a strong cold front beyond Nycatha in the north, the center and suburbs of the Overworld were violently hit by ice storms. This short bout of freezing rain brought a special phenomenon known as glaze to Belobog. Long icicles have formed on many structures and trees.

在筑城者庇佑下的贝洛伯格温暖始终，但少数情况下也会有这样的冻雨入侵，我们特地请到贝洛伯格的气象专家叶加德教授给我们简短地介绍了一下名为「冰风暴」的天气。

Thanks to the Architects' protection, Belobog remains warm all year long, but there are still rare occasions when such freezing rain enters the city. We have specially invited a Belobog meteorologist, Professor Yegard, to give us a brief introduction to the weather phenomenon called "ice storms."

记者米莉（以下简称：米）：叶加德教授您好。

Reporter Millie (hereinafter referred to as M): Hello, Professor Yegard.

叶加德（以下简称：叶）：您好。

Professor Yegard (hereinafter referred to as Y): Hello.

米：上周的时候，我们贝洛伯格近郊和下城区罕见地发生了冰风暴的天气，能大致给我们解释一下成因吗？

M: Last week, Belobog's suburbs and the Underworld experienced a rare ice storm. Can you give a brief explanation of the causes?

叶：我们气象台这边通常把「冰风暴」叫作「冻雨」，它们指的是同一种天气。说到冻雨之前，我们必须要先提到煦日节前后，贝洛伯格内部经常会出现的反常低温现象。

Y: At the weather station, we usually call and ice storm "freezing rain." They refer to the same meteorological phenomenon. Before we talk about freezing rain, I must first mention the abnormally low temperatures that often occur in Belobog around the Solwarm Festival.

米：也就是「贝洛伯格之冬」对吧。报社也在各个地区做好了通知。

M: I believe you're referring to the Belobog Winter, right? The news has made announcements about it in every region.

叶：在整体气温下降的条件下，恰好遇上了一股从贝洛伯格温室圈外闯进来的强冷空气，长驱直入来到城市近郊，形成了冻雨。而贝洛伯格的热岛气候是以城中为中心的，所以城中温度较高，只是形成了降雨。

Y: The general lowering temperature became combined with the sudden freezing air coming from outside the Belobog greenhouse area, which rushed to the suburbs and formed freezing rain. The urban heat island of Belobog has its core in the city center, so the temperature there was higher, causing only rain to form.

米：我家附近那边是雨夹雪的程度呢。冻雨之所以特殊，是因为它形成了「雨凇」的景观，那「雨凇」又是怎么形成的呢？

M: It's more like sleet where I live. What makes freezing rain special is the glaze. How is glaze formed?

叶：那是因为冷空气入侵时，冷暖空气交锋。锋面下的气温和地面温度降至冰点以下，而锋面上方的空气在冰点以上并且比较湿润，形成雨滴落入低于冰点的气层时，就会变成「过冷水滴」。

Y: That's because the cold and warm air collided when the cold air entered the city. Under that collision layer, the air and ground temperatures drop below freezing. But above that layer, the air is relatively wet and temperatures are above freezing. As raindrops fall into regions where the air temperature is lower than freezing, they form supercooled water drops.

米：「过冷水滴」是低于冰点的水滴吗？

M: So supercooled water drops are water droplets below the freezing point?

叶：没错，由于近地面气候比较低，所以「过冷水滴」一接触到建筑、树木、植被或者道路就会形成一层晶莹透亮的薄冰。「过冷水滴」在树枝上形成的「雨凇」，民间一般叫作「树挂」。

Y: Yes, since the temperature near the ground is lower, the supercooled water drops form a thin layer of crystal-clear ice when they touch buildings, trees, vegetation, or roads. These glaze formations formed by supercooled water drops on trees are what people usually call "icicles."

米：原来是这样。按教授您刚才的说法，「冻雨」其实是小概率事件吗？

M: So that's how it works. Based on your description, is freezing rain actually a rather rare occurrence?

叶：没错。贝洛伯格每年只在煦日节前后会有小幅的降温，时间其实并不是很长。市民们在确认保暖措施完备、道路安全的情况下，可以到近郊欣赏难得的「雨凇」美景。

Y: That's right. There's only a short time before and after the Solwarm Festival when air temperature decreases in which this natural phenomenon can occur. Citizens are free to enjoy this beautiful glaze scenery in the suburbs. With proper attire and safety conditions, of course.

米：感谢叶加德教授给我们带来的冻雨相关知识。

M: Thank you, Professor Yegard, for taking the time to teach us about freezing rain.

叶：不用客气。

Y: You're welcome.