绿色层顶

David+Feeley+张晓敏

Who gets to plan the cities of the future？ You do！ It may all start with the roof over your head. Roofs of future cities will look and feel cooler. "Green" plant covered and "Cool" white or pastel1） roofs have long been popular in Europe， the Middle East， and Canada. Now roofs that look more like meadows than asphalted2） streets， plus those that paint a pretty pastel picture， are becoming part of the "greening" of America.

未来的城市由谁来着手规划？由你来！这一切或许都可以从你头上的屋顶开始。未来城市的屋顶看上去和感觉上都将会更凉爽。在欧洲、中东和加拿大，一直都很流行将屋顶种满“绿色”植物并且刷成“凉爽的”白色或是柔和的色彩。现在，那些看上去更像草坪而不是沥青马路的屋顶，还有那些画着一幅美丽的彩色图画的屋顶正成为美国“绿化”的一部分。

Jackman School

Students， teachers and parents at Jackman Avenue Public School in Toronto， Canada， had a problem： heat. They knew air conditioners weren't an eco-friendly solution because they waste energy and just heat up the neighborhood. So， looking to the future， they used ultraviolet3） （UV） film4） and solar blinds for their windows， and added ceiling fans and shade trees. They also put a Green Roof on the school.

The Heat Island Effect

Cities full of buildings with Jackman School's problem are in big trouble！ The United States Environmental Protection Agency （EPA） says that due to the "Heat Island Effect"， cities and suburbs are 2 to 10 degrees Fahrenheit （F） hotter than nearby country areas. Tall buildings with flat roofs and narrow streets trap heat from cars， factories and air conditioners. This adds to global warming. In cold， northern locations， cities may stay a little warmer in winter， but most of the year they need more energy to get cool.

Cities have other problems too. They have increasing levels of pollution， which make people sick， and rainwater from roofs washes through city streets without becoming part of our needed watershed5）. How can the 3.3 billion people now living in our cities survive in the future as temperatures climb higher due to global warming？ Bob Fittro， of DesignandBuildwithMetal.com， says green roofs—those with a plant covering—can certainly help. "Where roofs are flat， plant covered systems have been shown to keep buildings cooler inside， and as an added benefit they turn roofs into enjoyable park-like spaces，" he says.

Green Roof Pros and Cons

On a summer day， the temperature of a roof can reach 140 to 190 degrees F. Think about it： an egg fries in a 158-degree F pan！ Covered with grass to absorb sunlight， the temperature of that same roof wouldn't rise above 77 degrees F. After a couple of years， plant roots get so dense that they act like a warm coat， lowering heating costs in winter， even when that coat is more brown than green.

Balmori Associates， an urban landscape design firm based in New York City， built a 35，000-squarefoot green roof atop Silvercup Studios in Queens， New York. The firm found a 30～50 percent reduction of energy use for climate control for the building in the summer and nearly a 50～100 percent reduction in spring and fall.

You can breathe deeply with a green roof， too， because they clean the air by catching particles of pollution， and use carbon dioxide to make more oxygen. They also absorb traffic， machinery and airplane noise. So future cities with Green Roofs will be cooler， cleaner and quieter.

Storm water is stored by a green roof and its plants return water to the air. Extra water is cleaned and cooled by plants before it leaves the roof. Jackman student research showed their green roof had about 75 percent less runoff water than before adding a green roof.

Balmori Associates planned a green roof for an environmentally progressive residential tower in New York City， called The Solaire， which stores rainwater not absorbed by its plants， along with the building's grey water6）， in a basement cistern7） where it is filtered and reused to irrigate8） nearby parks as needed.

Owners of the Fairmount Waterfront Hotel in Vancouver， Canada， save about $30，000 a year by using the herbs and vegetables growing on the building's roof.

Green roofs also are healthy， safe places to relax and play in a crowded city. Some local plants and animals even find a home there.

Making It Green

（and Yellow， Red and Brown）

A rooftop is a tough place to live. There are high winds， extreme hot and cold temperatures， and usually very little water. For its green roof， the Jackman team chose local plants with brightly colored flowers and shallow roots. Bergamot， yarrow， asters， geraniums， daisies， coneflowers and four kinds of sedum9） are included. Their "green" roof is actually shades10） of yellow， red， purple and brown. The Silvercup Studios' green roof has 20 different sedum varieties growing in a pattern of green strips and blocks that bloom in yellows， reds and pinks from spring to fall.

Tomorrow

Many groups have grand plans for future cities. One is a project by Balmori Associates called Shanghai Bund in China， where they propose to create a 20-meter green zone connecting the city to Huangpu River. With engineered islands to clean and filter water and generate energy， Shanghai Bund will be a zero-waste11） landscape. You'll see plenty of green roofs there.

The best choices will improve our lives and the cities we live in by respecting each other and the planet we so depend upon.

杰克曼学校的故事

加拿大多伦多杰克曼大街公立学校的学生、老师和家长们之前碰到过一个难题：炎热。他们知道开空调并不是个环保的方法，因为空调浪费能源，只会使居住区变得更热。所以，放眼未来，他们给窗户贴上了紫外线薄膜，装上了遮阳百叶窗，还安上了吊扇，栽了遮阴树。他们还为学校建造了绿色屋顶。

热岛效应

不少城市满是面临杰克曼学校这种难题的建筑，大麻烦也由此而来！美国环境保护署宣布，由于“热岛效应”，城市和郊区的温度会比邻近的乡村地区高出2～10华氏度（编注：1华氏度约等于17.2摄氏度）。平顶高楼和狭窄的街道令汽车、工厂以及空调散发的热量无法外散，而这又加剧了全球变暖。美国那些位于北部寒冷地区的城市在冬天也许仍能稍微暖和一些，但是一年中的大部分时候它们需要更多能源来降温。

城市还面临着其他问题。城市里有越来越严重的致人生病的污染，而且顺着楼顶流下来的雨水从城市的街道冲刷而过，却没有成为我们所需要的集水区的一部分。随着全球变暖导致气温不断升高，现在全球城市里居住的33亿居民未来要如何生存下去？DesignandBuildwithMetal.com网站的鲍勃·菲特罗称，绿色屋顶——那些有植物遮盖的屋顶——无疑是一大助力。“对于平顶的建筑，有植物覆盖的系统已经表明可以让建筑的内部更加凉爽，另外还带来一个额外的好处，就是把楼顶变成了像公园一样赏心悦目的地方。”他说道。

绿色屋顶的利与弊

夏日的白天，屋顶的温度可以达到140～190华氏度。想象一下：一颗鸡蛋在一个158华氏度的煎锅里煎着！同一个屋顶，如果上面铺了草坪来吸收阳光，其温度将不会超过77华氏度。几年之后，植物的根长得够密实，还可以当做房子的保暖外套，降低冬天取暖的费用——即便那时这件“外套”更接近棕色而不是绿色（编注：指冬天植物叶子变黄时）。

巴尔莫里建筑事务所是一家总部位于纽约市的城市景观设计公司，该公司在位于纽约皇后区的银杯工作室顶部搭建了一个35000平方英尺的绿色屋顶。这家公司发现，该建筑控制温度的能耗有所减少，夏天能耗减少了30%～50%，春秋两季则减少了近50%～100%。

拥有了绿色屋顶，你还可以深呼吸，因为这样的屋顶可以通过捕捉空气中的污染颗粒来净化空气，并能利用二氧化碳来制造更多的氧气。它们还可以吸收交通、机器以及飞机带来的噪音。所以，未来有绿色屋顶的城市将会更凉爽，更干净，也更安静。

雨水会被绿色屋顶贮存下来，再由屋顶的植物送回到空气中。多余的雨水会在离开屋顶前被植物过滤和降温。杰克曼的学生研究显示：他们加了绿色屋顶后，屋顶雨水流失量比之前减少了约75%。

巴尔莫里建筑事务所为纽约市一幢环保方面较为先进的住宅高楼设计了一个绿色屋顶。这幢高楼名为索拉里，它能将没有被屋顶植物吸收的雨水以及楼内的废水都存入地下室的蓄水罐里。这些水会在这里经过过滤，然后在需要时被用于浇灌附近的公园。

通过利用酒店屋顶生长的香草和蔬菜，加拿大温哥华费尔芒特海滨酒店的拥有者一年就可省下大约30000加元。

在拥挤的城市，绿色屋顶还是个放松、游玩的好去处，健康又安全。当地的一些植物和动物甚至还会在这里安家。

让屋顶变成绿色

（和黄色、红色和棕色）

在屋顶生存不易。那里有强风，有酷热或严寒，而且通常没什么水。杰克曼学校的设计团队给他们的绿色屋顶选择了当地一些花朵颜色亮丽和根须较浅的植物，有佛手柑、欧蓍草、紫苑、天竺葵、雏菊、金花菊，还有四种景天属植物。他们的“绿色”屋顶实际上有黄色、红色、紫色和棕色。银杯工作室的绿色屋顶则有20种不同的景天属植物，种的时候排成了绿色条纹和不同的方块组成的图案——从春天到秋天依次开出黄色、红色和粉色的花儿。

绿色屋顶的明天

许多组织对未来的城市都有宏伟的规划。其中之一就是巴尔莫里建筑事务所在中国规划的一个叫做上海外滩的项目。巴尔莫里建筑事务所提出建造一个20米长的绿色区域来连通上海和黄浦江。有这些人工设计的小岛来过滤清洁水资源并产生能量，上海外滩将会成为一个零废弃的景观。你在那儿会看到许多绿色屋顶。

这些最好的选择将会通过对彼此的尊重以及对我们如此依赖的地球的尊重来提升我们的生活品质，改善我们生活的城市。

1.pastel [?p?stl] adj. 柔和的；淡的（指颜色）；彩色粉笔画的；彩色蜡笔画的

2.asphalt [??sf?lt] vt. 用沥青（或柏油）铺（路）或覆盖（屋顶）

3.ultraviolet [??ltr??va??l?t] adj. 紫外线的

4.film [f?lm] n. （塑料）薄膜

5.watershed [?w??t??ed] n. （森林地带的）集水区

6.grey water： 洗盥污水；不净化就可再利用的家庭污水

7.cistern [?s?st?n] n. 地下蓄水罐

8.irrigate [??r?ɡe?t] vt. 灌溉

9.sedum [?si?d?m] n. 景天属植物

10.shade [?e?d] n. 色调

11.zero-waste： 零废弃，一种新型理念和设计原则，方法是运用可持续发展原则，管理资源和废弃物，目标是消除废弃物及有毒物质排放，减少所需资源，实现资源的再利用和再循环。

To Build a Green Roof 如何打造一个绿色屋顶

Are you thinking that your school should have a green roof？ There are lots of important considerations. Green roofs that will be intensely planted with trees and shrubs， and have people walking on them， should start with a strong， flat roof. This should be covered with waterproof， insulating， root-blocking barriers. Follow this with both water drainage and filter layers. Then add soil and cover it with a tightly woven material to keep wind from blowing the soil away. Poke your plants through this cover into the soil. Leave the roof edge and corners plant-free to prevent wind damage.

Isn't there an easier way？ Yes. Light-weight roofs can be made of two-to-four-inch thick pre-planted blocks snapped together and placed over water and root barriers. Planted with short， hardy plants， like sedums， these green roofs can neatly cover even sloped roofs.

你是不是在考虑你的学校也应该有个绿色屋顶？有许多重要的事情需要考虑。一个将要种植密集的树木和灌木、还能让人在上面行走自如的绿色屋顶首先应该是坚固而平坦的。在它的上面还应该铺上能防水、隔热、阻绝植物根系的多层阻隔物。紧接着，要在上面铺设排水系统和过滤层。然后再盖上土，并给土层罩上一层编织紧密的织物，防止风把土吹走。透过这层外罩把你的植物种进土里。要把这个绿色屋顶的边缘和角落都空着，以防大风造成破坏。

有更简单一些的方法吗？当然。可以制作轻型屋顶：将2～4英寸厚的提前种好植物的板子拼在一起，然后把它放在可以防水并能阻绝根系的阻隔层之上。要种一些低矮的耐寒植物，比如景天属植物，这样的绿色屋顶就连有点儿倾斜度的屋面都可以很好地遮盖。