< h1 class="ql-align-justify" > clouds and Earth's climate</h1>
While clouds can cover 3/4 of Earth's sky at any time, clouds remain one of the most mysterious factors in weather forecasting.
Clouds do more than just rain and snow. Scientists have now realized that by absorbing and reflecting sunlight, clouds also help control the flow of energy around Earth. In fact, the clouds floating above us have a much greater impact on Earth's climate than we think. The latest research on the relationship between clouds and climate warming gives us a new perspective on how clouds are viewed, which will help scientists more accurately predict future climate change. Here are some of the latest research advances made in this regard.
< h1 class="ql-align-justify" > cloud is the mysterious arbiter of Earth's climate</h1>
In the past, researchers thought the cloud's existence was relatively short-lived, so it was only seen as a recent indicator of weather changes, rather than a major factor influencing long-term weather changes, but now they are gradually realizing how much sunlight clouds receive on Earth. Sunlight is reflected into space, with implications for global climate change. Currently, scientists are using satellites, sensors and research planes to observe the effects of clouds as they travel between sunlight and heat.
The Earth absorbs the sun's heat and warms the air, while clouds are the product of hot air containing water vapor. As the altitude rises, the atmosphere becomes colder, while cold air keeps less water vapor at bay. Some water vapor is deposited on dust particles or salt particles, condensing into small water droplets or ice crystals, forming liquid or solid water. This is the cloud. Since clouds can scatter light, we can see clouds floating in the sky.
Sunlight through the clouds carries heat to the Earth's surface, and this heat eventually dissipates. How does the Earth remove this heat? There are two ways, one is direct radiation in the form of infrared energy, and the other is exposure to the atmosphere. Molecules (mainly carbon dioxide and water vapor) are absorbed by liquid water and frozen water in clouds. The sun's short-wave radiation is injected into the ground through the atmosphere, and the long-wave radiation emitted by the warming of the ground is absorbed by carbon dioxide and other substances in the atmosphere, thus producing the effect of atmospheric warming, that is, the greenhouse effect, so that life and heat on the earth can be obtained.
This phenomenon also explains why cloudy nights are usually warmer than sunny nights, as the Earth needs to release heat trapped in clouds during the day.
More than 20 years ago, scientists began to re-examine the role of clouds. Researchers at the time suspected that carbon dioxide and other greenhouse gases were linked to fossil fuels and caused the planet to overheat. Computer models also show that an increase in carbon dioxide content in the air increases the Temperature of the Earth, and warm air also contains more water vapor, which could increase the greenhouse effect by 50 percent.
However, in the early 1980s, meteorologists could not predict the impact of clouds on future long-term climate change. It wasn't until 1989 that American scientists published their findings: clouds have a cooling effect on the planet greater than their role in increasing heat. Clouds can reduce the heat of a light bulb of about 60 watts on the Earth's surface by 0.5 square meters. If there were no clouds in the sky, the Earth might be hotter than it is now.
< h1 class="ql-align-justify" > cloud may help prevent overheating in the tropics</h1>
There are several very hot areas in the tropical ocean, such as the western Pacific Ocean near Indonesia, where much water vapor evaporates, warming up the local atmosphere. Hot air should warm the oceans, evaporate more water, and produce more water vapor, which becomes an uncontrollable vicious circle. However, the sea temperature in the region rarely exceeds 30 ° C. Obviously, there must be a "braking system" to control the vicious circle in this area, and it is the cloud that studies the role of the "braking system". The skies of some tropical hotspots produce large numbers of Cumulonimbus clouds, forming an anvils that cover several square kilometers of water. The hotter the ocean, the more clouds there are on the ocean, the more anvils there are, and the more sunlight is reflected, curbing the effect of the ocean's continued warming.
<h1 class="ql-align-justify" > warming has led to a decrease in low-altitude clouds</h1>
According to a new study, as the oceans warm, the clouds floating over the northeast Pacific Ocean will gradually dissipate. The researchers call this phenomenon a "vicious circle" of warming. The study shows that low-altitude clouds can reflect sunlight back into space, lowering ocean temperatures and cooling the Planet, while warming will gradually reduce the low-altitude clouds that help cool the Planet. Low-altitude clouds are usually made up of water, including those that people see on cloudy days that are darker and flatter.
Computer simulations show that if warming increases the amount of clouds in low-altitude clouds, clouds can block incident solar radiation and cause cooling. In this case, the cloud provides a "negative feedback" effect on climate change; If warming reduces the amount of clouds in low-altitude clouds, it will bring more solar radiation. In this case, the cloud provides a "positive feedback" effect on climate change. The scientists noticed that for the past 50 years, clouds in low-altitude clouds have been in a "positive feedback" loop pattern. That is, a warming climate reduces cloud coverage, and as the amount of clouds decreases, the amount of sunlight hitting the Earth's surface increases, thus warming the weather. Scientists believe that the cloud data collected by different satellites will be different, and ground-based observations are subjective. So climate change trend analysis based on these imperfect observations is sometimes questionable, but the signals from the cloud are real.
In this way, further research on low-altitude clouds has special significance. Understanding the warming trends that are causing low-level cloud reductions will help improve the accuracy of cloud simulations in climate models to more accurately predict future climate change.
<h1 class="ql-align-justify" > oceanic stratus reflect sunlight like a mirror</h1>
A new study by an international team of more than 200 scientists shows that clouds over the Pacific Ocean have an impact on global climate and weather systems. According to the study, because some clouds in the Pacific Ocean are larger than in the United States, they have a large impact on Earth's climate.
Scientists are working on a system of clouds called "Earth's stratigraphic clouds." When the cold waters of the deep sea rush to the surface, the sea surface temperature drops, the water vapor condenses and rises, and the ocean stratus clouds are large. Formed. Two research aircraft were used in this study. As the plane passes through low-altitude clouds, scientists collect data from detectors mounted on the plane to understand how cloud systems form, how sunlight is reflected, and what determines the duration of cloud systems.
Cumulus clouds floating over the southeast Pacific Ocean generally do not exceed 2,000 meters above sea level and occur almost all year round. Scientists have begun to recognize the impact of these large clouds on the ocean on Earth's climate: They act like a giant mirror that reflects sunlight back into space, limiting the amount of sunlight reaching the Earth's surface.
The scientists involved in the study also wanted to understand whether mining activity off the coasts of Chile and Peru affected the characteristics of the cloud. During the mining process, some tiny mineral particles are carried into the upper atmosphere, forming water droplets when in contact with water vapor in the atmosphere. The scientists intend to collect data to assess whether mineral particles will have an impact on rainfall, and whether clouds filled with mineral particles will reflect sunlight more than normal clouds.
<h1 class="ql-align-justify" > glowing clouds often occur or are associated with greenhouse gas emissions</h1>
For the first time, Nordic residents saw strange glowing clouds a few years ago. The photographer photographed the strange silver-blue layers, like tendrils, through the bleak skies of Denmark, Northern Ireland and Scotland.
The glowing cloud is the highest cloud in earth's atmosphere, reaching an altitude of 80 kilometers above the earth's surface. Due to altitude, glowing clouds can glow in the sunlight below the horizon before sunrise or after sunset. Glowing clouds are usually colorless or light blue, occasionally red, green, and blue. The shape of a glowing cloud is sometimes a strip with no special function, sometimes with unique stripes, wavy shapes, or swirls. Like familiar low-altitude clouds, glowing clouds are formed by water droplets attaching to the surface of dust particles (tiny crystal ice crystals of 40 to 100 nanometers). The sources of high-altitude dust and water vapor are uncertain. Some believe that dust may come from tiny meteors, or from tropospheric volcanic ash and atmospheric dust, and that water vapor may rise to the upper layers through gaps at the top of the convectosphere.
Humans haven't found glowing clouds for a long time, and they haven't fully understood the causes of glowing clouds. Glowing clouds were first discovered in two years after the 1883 eruption of Krakatoa, but it is unclear whether the appearance of luminous clouds was related to the eruption. In addition, solar activity, climate change, space dust and rocket launches may also be responsible for this cloud phenomenon.
Bright clouds usually appear only between 500 and 700 north and south latitudes. They appear in the Northern Hemisphere from mid-May to mid-August and in the Southern Hemisphere from mid-November to mid-February. Although bright clouds appear in the Northern and Southern Hemispheres, the frequency observed in the Northern Hemisphere is more pronounced than in the Southern Hemisphere, possibly due to the small land area in the Southern Hemisphere and the relatively small number of observers.
In recent years, however, the range of luminous clouds has expanded to areas with latitudes of 40°, and the number has increased and the brightness has become stronger. The reason for the enlargement of luminous clouds and the increase in frequency remain unclear. The study found that glowing clouds are extremely sensitive to the climatic environment, so some scientists speculate that increased greenhouse gas emissions could lead to frequent occurrences of glowing clouds — greenhouse gases that cause the Earth's upper atmosphere to cool down, and low temperatures are necessary for cloud formation.
Ten years ago, NASA launched the Charged Particle Gas Release Test rocket. The purpose of the test is to create artificial clouds in the outermost layers of the Earth's atmosphere to simulate the phenomenon of luminous clouds. The scientists hope to use this test to study the distribution of gas and dust particles within luminous clouds.
Scientists believe that in unpredictable weather changes, no matter what mechanism is employed, they can eventually build predictive models to accurately predict whether clouds will change the atmosphere as a result of human behavior. Impact on the global climate.