Dust molecules help limit climate change?

For decades, scientists have wondered whether the condensed nuclei of artificial clouds - particles suspended in the atmosphere - increase cloud cover around the Earth, and thus help limit global warming or not. Scientific studies have so far not achieved any progress in finding solutions to the above question.

Two scientists from the Max Planck Meteorological Research Institute in Hamburg and the US National Oceanic and Atmospheric Administration (NOAA) have published in Nature that the interaction between nuclear condensed clouds and clouds and Rain depends very much on many factors that so far people have not studied carefully. At the same time, they come up with a research idea that can help complement these knowledge gaps of humanity.

Greenhouse gases that heat up the Earth's atmosphere also have their enemies: particles suspended in the atmosphere (also known as aerosols) . They are naturally born, for example when wind blows dust in the desert, or through human activities. Much of the artificial cloud condensation nucleus comes from sulfur dioxide, a gas that occurs when humans burn fossil fuels.

Cloud condensing nuclei are regarded as atmospheric coolers, compensating in part for the process of greenhouse gases causing global warming. Climate researchers imagine this cooling mechanism simply as follows: when condensed nuclei enter the clouds, they attract water molecules and thus act as nuclei to form droplets. The more condensed nuclei that exist in the cloud, the more water droplets are formed. When artificial dust particles combine with natural dust, the number of drops increases. As a result, the average size of the particles decreases.

Since the droplets don't fall to the ground, it can be said that the condensed nucleus prevents the clouds from forming rain and extends the cloud's 'longevity'. Therefore, the amount of cloud cover around the Earth's surface increases. Clouds radiate the sun's rays and cause them to return to outer space, so the cloudy sky means that the atmosphere absorbs less heat than when it is clear. Climate researchers call this mechanism 'cloud age effect'.

However, up to now, people have not been able to quantify the impact of cloud age on the climate. Estimated figures vary widely: words that do not affect the effect enough to offset the carbon dioxide levels increase atmospheric heat.

Each cloud has its own characteristics.Therefore, it is necessary to conduct research on the types of clouds most affected by condensed nuclei.(Photo: Max Planck / Stevens Meteorological Research Institute)

According to Bjorn Stevens of the Max Planck Meteorological Research Institute in Hamburg and Graham Feingold of the Earth Systems Laboratory of NOAA, this ambiguity is due to the explanations surrounding the cooling mechanism of condensed nuclei. clouds have been oversimplified. The two researchers analyzed the articles on this topic from 1970 until now. In their survey of articles, the results show that there are some ideas that are contrary to the cloud age effect: for example, a field study conducted several years ago announced that clouds in the region Trade Wind turns into rain faster, not slower, when condensed nuclei are present.

After analyzing the documents, Stevens and Feingold came to the conclusion that: 'The clouds react with the nucleus condensing in a very complex way, and this reaction depends greatly on the type as well as the state. of clouds . We, climate researchers, need to focus more on cloud systems and better understand them. '

According to the researchers, processes in the clouds that neutralize, or even deny, the effects of cloud condensation have not been considered. For example, when a cumulative cloud interacts with the cloud condensing nucleus, it does not transform into rain. However, this also leaves certain consequences: fluid (including gas and water) appears and evaporates above the cloud. The air above the cloud is cooled and easily affected by the cumulative cloud extending upward. The higher the cumulus cloud, the more likely it is to rain. Therefore, in such cases, the condensed nucleus does not prevent clouds from forming rain.

Stevens and Feingold believe that due to such buffering mechanisms, the cooling effect of cloud condensing nuclei is very small. However, they acknowledge that the cloud lifetime effect is not an unreasonable explanation of the processes caused by condensed nuclei in clouds. 'However, all forms and cloudy states are not the same,' Stevens said. He called on the scientific community to reconsider the study of cloud condensation and contact cancer research: 'People used to think that cancer had only one mechanism. But today, we know that every type of cancer needs an independent study. '

According to Stevens and Feingold, research must first identify cloud systems that are most affected by condensed nuclei. They propose to start with common types of clouds, such as flat cumulus clouds on the ocean (Trade Wind cumulus clouds).

A project jointly implemented by the two Max Planck Meteorological Research Institutes and the Caribbean Institute of Meteorology and Hydrology will start in this direction. The two-year field survey will begin on Barbados Island in the Trade Wind region in 2010. Researchers will place remote sensors on the island's wind-shoreline. Ground measurements will complement the measurements carried out directly on the clouds conducted by the German HALO aircraft. The data obtained from this measurement campaign helps scientists better understand the link between the factors: cloud cover, rain, local meteorological conditions and cloud condensing nuclei.

Refer:

Bjorn Stevens, Graham Feingold.Untangling nuclei condense clouds effects on clouds and precipitation in a buffered system.Nature, October 1st 2009, Volume 461, pages 607 - 613 DOI: 10.1038 / nature08281