Reading the Sky　觀天知天氣

史蒂夫·努比　俞月圓

Long before the weather channel， our pioneer ancestors and native tribes looked for signs in nature to forecast the weather. The sky was their primary focus， but how the sky， air， and barometric pressure affected plants， animals， and people were also tell-tale signs.

Over time， simple sayings evolved to remind us of the weather to come， although some of them arent so accurate from a scientific standpoint.

Weather sayings from folklore：

Red sky at night， sailors delight; Red sky at morning， sailors take warning.

When ditch and pond offend the nose， look for rain and stormy blows.

Chimney smoke descends， our nice weather ends.

A ring around the sun or moon， means rain or snow coming soon.

Rainbows in the morning give you fair warning.

Its one thing to remember some old adages， but its easier to remember if you understand the science behind the sayings.

Reading the smoke

Smoke from a fire can give us some very direct clues about atmospheric pressure and the potential for good or bad weather.

Smoke rising

Rising smoke indicates a high-pressure area in the vicinity. High pressure is associated with fair weather and clear skies.

Smoke collapsing

When smoke collapses and curls， its indicative of a low-pressure system in the area. Indoors， the unexpected presence of wood smoke is another sign. Low pressure is associated with stormy weather.

Reading the sky

Red Sky at Night… is NOT a sailors delight！ This old adage is scientifically incorrect. The rotation of the Earth causes prevailing winds1 to come from the West. The sun sets in the West and a red sky indicates a significant cloud bank. Heavy clouds coming from the West with the prevailing winds is not a promise of delightful weather but the opposite.

Red Sky in Morning… is when sailors neednt take warning. Here again， the sun rises in the East and a red sky is due to cloud coverage. Those big clouds are receding from your location as the westerly prevailing winds carry them away from you.

Sun halos and moon halos

A ring around the sun or moon is referred to as a “Sun or Moon Halo.” Haloes are caused by high altitude ice-crystals in Cirrus clouds2. Because Cirrus clouds are a signal for impending rain， a ring around the moon usually means a warm front is coming， bringing rain with it. The same is true of sun haloes.

Reading rainbows

A rainbow in the western sky in the morning indicates rain. Here again， prevailing westerly winds will bring that moisture towards your location. The opposite is true for a rainbow in the East. The prevailing winds will move the moisture and rain away from you.

Reading the moon

A clear moon in a clear sky indicates no imminent3 moisture but could be a harbinger of cooler temperatures overnight and into the morning.

Scattered clouds across the Moon are a sign of moisture-laden clouds and often are a portent of rain.

Reading the flowers

Humidity strengthens smells in the air and fragrant flowers will be very noticeable as a result.

Wind

Wind is the result of high and low-pressure shifts in an area. As a rule， westerly winds indicate good weather if no clouds are apparent and easterly winds are an indication of bad weather. If youve ever heard of a NorEaster4， its due to this east wind condition.

Reading temperature

The cricket trick

A crickets metabolism changes in lockstep with5 temperature changes. Count the number of times a cricket chirps in 14 seconds and add 40 to that number. The resulting number approximates the temperature in Fahrenheit.

Reading the clouds

Reading cloud shape

Clouds that are high， white， and wispy indicate good weather while clouds that are low， thick， and dark mean stormy weather. Flat clouds mean the air is stable while fluffy clouds mean the air is unstable.

Reading cloud color

Clouds come in four flavors： white， gray， black， and brown. Each means something different.

Black clouds indicate a coming storm that does not have strong winds.

Brown clouds indicate a coming storm that has strong winds.

White clouds mean good weather， though a storm could be imminent.

Gray clouds indicate a new or a light storm. Gray skies can also mean that the storm is affecting a large area and may remain.

Reading altitude

High clouds usually mean that they are farther away but could become a weather threat up to 36 hours later. Lower clouds mean that bad weather is coming.

Movement

Gathering low clouds are a sign of bad weather. Rising and spreading clouds indicate the weather is clearing.

Reading the animals

Animals are very much in tune with nature and their instincts and response to conditions are a good indicator of weather to come.

Birds

Birds can sense air pressure patterns.

If you see birds eating during a storm， then it will likely last.

If you see flocks of birds migrating in the sky， the weather will likely be good.

When a storm is approaching， its believed that birds fly lower in the sky.

Frogs

The louder the frogs sing， the stronger the rain.

Turtles

Turtles head to higher ground before a storm. You may also see them on the road a day or two before a rain.

Snakes

If you see a snake in an unexpected place or time when the snake would typically be in its nest， bad weather is coming.

Butterflies and Bees

If you dont see bees and butterflies when and where you would expect to see them， there could be a storm coming.

Ants

Ants build up their mounds6 and create steep sides if theres a storm coming.

我們開疆拓土的先祖和土著部落居民早就會根據大自然中的跡象來預報天氣，那會兒離天氣頻道的出現還早得很。他們主要看的是天空，但天空、空氣和大氣壓對植物、動物與人類的影響也能表露天象。

久而久之，形成了一些簡明易懂的說法，提醒我們天氣會如何變化，盡管從科學的角度看，其中部分說法并不是那么準確。

有關天氣的民諺：

晚霞水手喜，朝霞水手憂。

溝渠水臭，風雨臨頭。

煙囪冒煙往下走，晴好天氣到了頭。

日暈月暈，雨雪將臨。

晨起有虹，如聞警鐘。

記住一些舊時諺語是個辦法，但如果能弄明白它們背后的科學原理，就會好記一些。

觀煙

燃燒產生的煙能以十分直觀的方式，提供關于氣壓和天氣趨勢的信息。

煙氣上升

煙氣上升，說明附近地區處于高氣壓區。高氣壓意味著天氣晴好、天空明凈。

煙氣下沉

如果煙氣下沉、卷曲，說明該地存在一個低壓系統。室內突然聞到木柴燃燒的煙味，也是存在低壓系統的信號。低氣壓會帶來風暴。

觀天

看到晚霞，水手可不會高興！這條古老的諺語不符合科學事實。地球自轉使西風成為盛行風。太陽從西邊落下，紅彤彤的天空說明空中云量豐富。從西邊順著盛行風飄來的大量云朵并不會帶來讓人開心的好天氣，情況恰恰相反。

而如果出現了朝霞，水手并不需要有所警覺。和上面說的例子一樣，太陽從東邊升起，東邊天空紅彤彤是因為那里云量豐富。那些大塊的云朵正在離你遠去，是因為盛行西風正在將它們推向離你更遠的地方。

日暈和月暈

太陽或月亮周圍出現的環被稱為“日暈”或“月暈”。出現“暈”是因為高海拔的卷云中有冰晶。由于卷云預示著很快要下雨，月亮周圍出現光環通常說明攜帶雨水的暖鋒即將過境。日暈的情況也一樣。

觀彩虹

早晨在西邊的天空看到彩虹，說明要下雨了。與上面的例子同理，盛行西風會把西邊的水汽向你所在的位置輸送。如果東邊出現彩虹，情況就正好相反。盛行風會推動水汽和雨離你遠去。

觀月

如果天空明凈、月亮看得很清楚，說明空氣中濕度不會太高，但這也可能預示著當天夜間到次日清晨將要降溫。

如果疏落的云朵遮住了月亮，說明云中水汽已飽和，這通常是降雨的前兆。

觀花

濕度升高后，空氣中的味道會更強烈，花朵的芬芳也會十分明顯。

風

風是某一地區氣壓高低變化的結果。一般來說，如果刮西風，又看不到多少云，說明會有好天氣，而刮東風則意味著天氣不好。你也許聽說過“東北風暴”，它也源自這種刮東風的狀況。

觀測氣溫

借蟋蟀察氣溫

蟋蟀的新陳代謝與溫度的變化有十分緊密的聯系。數一數蟋蟀14秒以內鳴叫的次數，再加上40，差不多就是當前的華氏溫度。

觀云

觀云形

如果云位置較高、顏色雪白、如絲如縷，說明接下來天氣晴好;如果云位置較低、厚重、陰沉，說明暴風雨將要來臨。云朵扁平，說明大氣比較穩定，云朵蓬松，則說明大氣不怎么穩定。

觀云色

云朵可能有四種顏色：白色、灰色、黑色和棕色，每一種都預示著不同的天氣狀況。

黑色云說明暴雨即將來臨，但不會有大風。

棕色云說明要有暴風雨，會刮強風。

白色云說明天氣不錯，不過也可能有一場暴雨正在迫近。

灰色云說明有一場新的風暴正在醞釀，或者風雨不強。天空呈灰色還可能意味著風雨影響范圍很大，并有可能持續。

觀云高

一般來說，海拔較高的云離得比較遠。但到36個小時之后，天氣也有可能會轉差。云所處的海拔較低，意味著壞天氣就要來了。

觀云動

如果云在低處不斷積聚，說明會有壞天氣。云上升、散開，說明天氣正在轉晴。

觀察動物

動物始終與大自然步調一致，了解它們的本能，觀察它們對環境狀況的反應，對預報天氣很有幫助。

鳥類

鳥類能感覺到氣壓的變化。

如果看見鳥兒在風暴中吃東西，那這場風暴很可能將持續。

如果看見一群又一群鳥兒飛過天空，通常會有好天氣。

如果暴風雨將要來臨，一般來說鳥兒會低飛。

青蛙

蛙鳴越響，降雨越強。

烏龜

暴風雨之前，烏龜會往高處去。下雨之前一兩天，你也許會在馬路上看見它們。

蟒蛇

如果本該待在巢穴里的蟒蛇在某時某地意外出現，就要有壞天氣了。

蝴蝶與蜜蜂

如果本該在某時某地出現的蜜蜂和蝴蝶沒有現身，就該有壞天氣了。

螞蟻

如果暴風雨即將到來，螞蟻會建起小土丘并在四周壘出陡坡。

（譯者為“《英語世界》杯”翻譯大賽獲獎者）

1 prevailing wind盛行風。地球南北半球的中緯地區為盛行西風帶。

2 cirrus cloud卷云。? 3 imminent迫近的;即將來臨的。

4 生成于北大西洋的溫帶氣旋，主要影響美國東北部、加拿大東部沿海等北美東岸地區。? 5 in lockstep with步伐一致，形容有緊密的關聯。

6 mound土丘，小土墩。