全球黯化
Global dimming

context: zh_tw: 20 世紀 60 年代晚期，麥克海爾・伊萬諾維奇・布迪科使用一個簡單的二維能量平衡氣候模式研究冰的反射率。他發現 “冰 - 反照率” 反饋在地球氣候系統中產生了一個正反饋迴圈。冰雪越多，被其反射回太空中的太陽輻射就越多，從而使得地球變得越冷，進而又產生更多的冰雪。其他的研究也發現空氣汙染或火山噴發可能會引發一個冰期的開始。20 世紀 80 年代中期，蘇黎世聯邦理工學院的一個地理學研究者大村纂發現到達地球表面的太陽輻射在過去的 30 年裡已經減少了超過 10%。他的發現顯得與全球變暖的趨勢（自 70 年代全球平均溫度已經在升高）相沖突。因為到達地球表面的陽光越少，地球應該越冷才對。大村在 1989 年發表了他的發現 “全球輻射在歐洲的長期變化”。隨後，其他研究者也陸續發現相似現象。比如 Viivi Russak 在 1990 年的 “愛沙尼亞近幾十年來的太陽輻射、雲量、大氣透明度的趨勢”，和 Beate Liepert 在 1994 年的 “德國的太陽輻射 —— 觀測到的趨勢以及造成原因的估計”。在蘇聯也觀測到黯化現象。格里・斯塔希爾（Gerry Stanhill）在好幾篇論文中（參見參考資料）研究了世界範圍內的黯化現象，並且確定了 “全球變暗（global dimming）” 這個術語。20 世紀 80 年代晚期在以色列和荷蘭的獨立研究顯示，儘管各地的跡象都表明全球氣候正在變熱，但陽光總量卻是在明顯減少。黯化的速率在各地有所不同，但平均值大概為每十年減少 2-3%。這個趨勢從 90 年代早期開始有所逆轉。由於很難精確的標定觀測使用的儀器，再加上空間覆蓋度不夠，使得很難得到精確的黯化速率的全球觀測。但是黯化的現象無可否認。
en: In the late-1960s, Mikhail Ivanovich Budyko worked with simple two-dimensional energy-balance climate models to investigate the reflectivity of ice. He found that the ice-albedo feedback created a positive feedback loop in the Earth's climate system. The more snow and ice, the more solar radiation is reflected back into space and hence the colder Earth grows and the more it snows. Other studies found that pollution or a volcano eruption could provoke the onset of an ice age.In the 1980s, Atsumu Ohmura, a geography researcher at the Swiss Federal Institute of Technology, found that solar radiation striking the Earth's surface had declined by more than 10% over the three previous decades. His findings appeared to contradict global warming — the global temperature had been generally rising since the 70s. Less light reaching the earth seemed to mean that it should cool.  This was soon followed by others: Viivi Russak in 1990 "Trends of solar radiation, cloudiness and atmospheric transparency during recent decades in Estonia", and Beate Liepert in 1994 "Solar radiation in Germany — Observed trends and an assessment of their causes". Dimming has also been observed in sites all over the former Soviet Union. Gerry Stanhill who studied these declines worldwide in many papers coined the term "global dimming".Independent research in Israel and the Netherlands in the late 1980s showed an apparent reduction in the amount of sunlight,  despite widespread evidence that the climate was becoming hotter. The rate of dimming varies around the world but is on average estimated at around 2–3% per decade. The trend reversed in the early 1990s.
qas: question: zh_tw: 李培特什麼時候觀測到類似的趨勢？
en: When did Liepert observe similar trends?
answers: zh_tw: text: 1994
en: text: 1994

context: zh_tw: 化石燃料（比如柴油和）和樹木的不完全燃燒會排放黑碳顆粒物到空中。雖然黑碳（大部分是以碳黑的形式存在）在地表空氣汙染物中只佔很小比例，但是它對大概 2 公里（1.2 英里）左右高度的大氣有很顯著的加熱效應。它還會因為吸收太陽輻射而使得海洋表面變暗。20 世紀 90 年代在馬爾地夫的實驗（透過比較群島南北的大氣）表明從印度吹來的汙染物會使得汙染雲團下的地面要少接受 10% 的陽光。
en: The incomplete combustion of fossil fuels (such as diesel) and wood releases black carbon into the air. Though black carbon, most of which is soot, is an extremely small component of air pollution at land surface levels, the phenomenon has a significant heating effect on the atmosphere at altitudes above two kilometers (6,562 ft). Also, it dims the surface of the ocean by absorbing solar radiation.Experiments in the Maldives (comparing the atmosphere over the northern and southern islands) in the 1990s showed that the effect of macroscopic pollutants in the atmosphere at that time (blown south from India) caused about a 10% reduction in sunlight reaching the surface in the area under the Asian brown cloud — a much greater reduction than expected from the presence of the particles themselves.
qas: question: zh_tw: 不完全燃燒的柴油會產生什麼顏色的煙霧？
en: What is the color of smoke that incomplete combustion of diesel  can produce?
answers: zh_tw: text: 黑
en: text: black