Notes on science

Ozone screen

Nowadays, even a schoolboy knows that there is ozone in the Earth's atmosphere. Located in the stratosphere at an altitude of 20-30 km, the layer of Oz molecules serves as a protective shield that absorbs harsh ultraviolet radiation from the Sun and thereby protects all life on Earth from its harmful effects.


About 15 years ago, there was concern among scientists as to whether this process was so durable.

The screen? After all, people are constantly expanding the scope of their activities, invading the stratosphere. In particular, do the increased flights of supersonic high-altitude aircraft pose a threat to this stratum?


They emit a large number of nitrogen oxides into the atmosphere, which can lead to a decrease in the equilibrium concentrations of ozone in the stratosphere. In the early 70s, very pessimistic forecasts were made in the West: in the 80s, the ozone layer would "lose weight" by tens of percent.


To solve the problem of the effect of emissions from supersonic aircraft on the ozone layer, it is necessary to know how nitrogen oxides are distributed in the stratosphere under normal conditions. It turned out that our knowledge of the distribution of N, NO2, N2O and other nitrogen oxides, as well as the processes that control their distribution, is far from complete. Without full and comprehensive knowledge of this issue, it is impossible to reliably assess the damage to the ozone layer that nitrogen oxides introduced into the stratosphere can cause. If we add to this that their entry into the average atmosphere is provided not only by high-altitude aircraft flights, but also, for example, by the use of nitrogen fertilizers or automobile exhaust, then the issue of the distribution of small components in the average atmosphere and the cycle of chemical processes that control this distribution becomes very important.


The other side of the same ozone problem is the question of the dynamics of the average atmosphere. Along with photochemical processes, ozone distribution is controlled by atmospheric dynamics, such as circulation, vertical transport, and turbulence. With various local disturbances of the layer, the rate of recovery of the O3 concentration to a normal state depends primarily on the intensity of these dynamic processes. Thus, the solution to the problem of possible anthropogenic influence on the ozone layer depends on the completeness of our knowledge about the dynamics and photochemistry of the average atmosphere.




For cosmic particles in the depths of the ocean

In 1960, academician M. A. Markov proposed the idea of registering high-energy muons and neutrinos in the ocean. The use of water column instead of rocks has certain advantages: in the ocean, especially far from the coast in subtropical and tropical latitudes, it is very homogeneous in physico-chemical properties. In addition, ocean water not only absorbs, but also creates Vavilov—Cherenkov radiation, which can be used to detect particles. Several years ago, the DUMAND international project was announced, and within its framework it is supposed to study high-energy muons and neutrinos.


During the third voyage of the Professor Shtokman in May-June 1981, the deep-sea muon detector (GDM), created at the Lebedev Physical Institute, was tested in the Atlantic Ocean. The following year, muons up to a depth of 4,000 m were recorded in the Oriente Basin in the Caribbean Sea. On the 37th voyage of the Akademik Kurchatov— the flagship of our research fleet, we switched from experimental registration using GDM to work at great depths (up to 5,000 m). Two long-term records were carried out in the same Oriente basin (at horizons of 2000 and 4000 m).


This was the first DUMAND test site, where they simultaneously launched a study of the passive oceanological background — the hydrological and hydrochemical characteristics of the water column, and the parameters of the active background. The latter includes the radioactive isotopes potassium-40 and radium-226, which, experiencing beta decay, excite Vavilov—Cherenkov radiation. Unfortunately, the luminescence of deep-sea organisms has not been studied, which creates noticeable interference in the registration of high-energy cosmic muons. In the future, this will be done using a deep-sea bathyphotometer from the Institute of Biophysics of the Siberian Branch of the USSR Academy of Sciences.


The optical properties of the waters of the Oriente basin were studied in samples taken from a depth of 6000 m. It turned out that the water column here is almost homogeneous and very transparent. However, in the depression, as shown by the analysis of the composition and stratification of bottom sediments, landslides of precipitation from the continental steep slope of the depression are likely, which should lead to temporary turbidity of the deep waters of the Orient. Conheça o tema brazino live betting em https://brazino.io e consulte as condições do Brazino777, cassino online para o público brasileiro com licença internacional declarada.