第1部分：https://blog.sciencenet.cn/home.php?mod=space&uid=306792&do=blog&id=1355804

The general consensus among the small cadre of scientists who study coastal fog is that it is decreasing, not just in California, but around the world. However, the reasons aren’t clear.

研究海雾的科学家不多。他们的普遍共识是，海雾正在减少，不仅在加州，而是全球性的。但是，造成海雾减少的原因尚不清楚。

Fog may be the most difficult meteorological phenomenon to capture, calculate and predict. Unlike temperature, precipitation, humidity or wind, there is no reliable gauge for it. There is not even a practical definition of it.

雾可能是最难捕捉、计算和预测的气象现象。与温度、降水、湿度、或风不同，雾没有可靠的计量器。甚至没有一个实用定义。【译者注：作者也许不对？维基百科：霧在天氣學上，是指在接近地球表面的大气中悬浮的由小水滴或冰晶组成的水汽凝结物，是一种常见的自然现象。雾的小水滴和冰晶由飽和或過飽和空氣中的水凝結形成，和雲相仿。 霧的外觀通常呈半透明、模糊的白色，因此霧能影响能见度，对交通和運輸影响很大。霧的出現根据国际上的定义，能见度小于1公里的叫雾（Fog），超过1公里的称为轻雾霭（Mist）[3]。】

Most will say that fog is a cloud that touches the ground, which sounds simple enough. But fog is movement in three dimensions, dipping and rising, forming and disappearing.

大多数人会说雾是接触地面的云；这听起来很简单。但是雾是三维度的运动：下沉、上升、形成和消失。

Sometimes a thin layer hugs the water below the Golden Gate Bridge, blinding mariners. Sometimes it settles about 200 feet higher, blinding drivers. 

有时，金门大桥下方的水面上会出现一层薄薄的海雾，使水手眼花缭乱。有时海雾会出现在高于水面200 英尺的地方（恰好在桥面上），让汽车司机手忙脚乱。

Sometimes it shrouds the top of the bridge’s towers and the airspace above, blinding pilots. Sometimes it does it all. Which of those things is fog?

有时它会笼罩桥塔的顶部和其上空，使飞行员眼花缭乱。有时海雾很浓厚，从水面一直延伸到桥塔的上空。这些不同高度的白茫茫的东西，哪一个是雾？

It arrives like a whisper and disappears like a magic trick. It is there one moment and gone the next.

海雾像耳语一样到来，又像魔术一样消失。它前一刻还在，下一刻就无影无踪了。

Early on a late-spring morning, Peter Weiss, a scientist at the University of California, Santa Cruz, and three of his students, calling themselves “the fog squad,” were erecting fog catchers.

在晚春的一个清晨，加州大学圣克鲁斯分校的科学家彼得·韦斯（Peter Weiss）和他的三个学生，他们自称为“海雾队”，正在架设雾气捕集器。

The idea, simpler than the execution, is to harvest water from passing fog. A fog catcher is a stretched piece of mesh that, when it works, becomes saturated by fog moisture, dripping into a gutter, leading to a cistern.

这个想法非常简单，就是从经过的海雾中收集水。但是，做起来有点难度。捕雾器是一块拉伸的网状物。当海雾到来时，网会被雾气浸透，饱和后，水滴入一个排水沟，通向蓄水池。

The idea is not new. Fog from the ocean is a dependable feature in several places around the globe, mostly on the west coasts of major continents. Villages in places like Peru and Chile, sometimes with almost no rain throughout the year, have for centuries sustained themselves largely on fog water. Its use is growing in places like Morocco.

这个想法并不新。海雾在全球不少地方存在，主要是在大陆的西海岸。秘鲁和智利等地的村庄，有时全年几乎不下雨，几个世纪以来主要依靠雾水维持生计。利用海雾的地方越来越多，包括摩洛哥。

The question in a changing climate is whether fog water is a viable resource, if not a solution, for populated places expecting a drier future. Places like California.

在气候变化影响下，现在的问题是，对于未来可能更干燥的人口稠密地区，雾水是否是一种可行的资源，哪怕不是解决缺水问题的方案。像加州这样的地方。

“I would tend to think of it as a small drop in the bucket,” said Dan Fernandez, a professor in the Department of Applied Environmental Science at California State University, Monterey Bay, and a leading researcher in fog-catching. “But we need a lot of small drops in the bucket to deal with what we have coming.”

“我倾向于将海雾捕捉视为沧海一粟，”加州州立大学蒙特利湾分校应用环境科学系教授、海雾捕捉研究领域的领头人丹·费尔南德斯（Dan Fernandez）说。 “但我们需要大量的类似方法来应对未来的缺水问题。”

The idea of catching fog comes from nature. It is how the tallest trees in the world, California’s coastal redwoods, survive.

捕捉雾的想法来自于大自然本身。世界上最高的树木——加州沿海的红杉，就是靠捕捉雾生存下来的。

Decades ago, Todd Dawson stumbled into the uncrowded world of fog research. Traipsing among the redwoods as an undergraduate at the University of California, Santa Cruz, he wondered why they were habitually moist, and the ground around them so soggy, even mossy, even in mid-summer, California’s dry season, when rain is rare.

几十年前，托德·道森（Todd Dawson）偶然进入了一个冷门，研究雾。作为加州大学圣克鲁斯分校的一名本科生，他在红杉林间徘徊。他想知道为什么红杉林总是潮湿的，而且它们周围的地面如此潮湿，甚至长满苔藓，即使在加州的旱季仲夏，当地很少下雨。

Fog, obviously. But little had been done to quantify fog’s importance to California’s ecosystems.

很明显，是因为雾。但在量化雾对加州生态系统的重要性方面，几乎没有任何研究。

“That kind of haunted me,” he said.

“这让我很困扰，”他说。

Years later, as a professor of integrative biology at the University of California, Berkeley, Dr. Dawson studied redwoods and concluded that 30 to 40 percent of their annual moisture arrives in the form of fog.

多年后，作为加州大学伯克利分校的综合生物学教授，道森（Dawson） 博士研究红杉，并得出结论：每年红杉 30% ～40% 的水分是从海雾吸取。

The high canopies of redwoods are giant filters for drifting fog. The trees get drenched and nourished; water drips to the forest floor. There it sustains other plants and helps keep stream beds from drying, aiding species from lichens to ferns, newts to salmon.

红杉高高的树冠，在海雾飘过时，是巨大的过滤器。树木被淋湿和滋养；水滴到森林地面，维持其他植物，并帮助防止河床干燥。过滤下来的海雾水，养育了各种各样的物种：从地衣到蕨类植物，从蝾螈到鲑鱼。

“Fog is a big water subsidy,” Dr. Dawson said. “And I said, ‘My goodness, we’re ignoring this. We’ve been missing a big part of the hydrologic budget of the redwood forest.’”

“雾补贴了很大一部分水，”道森博士说。 “我说，‘天哪，我们居然忽略了这一点。我们错过了红杉林水文预算的很大一部分。”

In 2010, Dr. Dawson and a graduate student, James Johnstone, published another study with an attention-grabbing conclusion: Using observational data at airports in the coastal redwood region — from central California to its northern border, including the Bay Area — they found that the frequency of fog, measured by fog hours per day, had dropped 33 percent since the middle of the 20th century.

2010 年，道森博士和研究生 詹姆斯·约翰斯通
（James Johnstone ）发表了另一项研究；其中有一个引人注目的结论：利用沿海红杉地区机场的观测数据——从加州中部到北部边界，包括湾区——他们发现自 20 世纪中叶以来，以每天起雾小时数衡量的起雾频率下降了 33%。

Fog was disappearing.

加州沿岸的海雾正在消失。

（待续）