Carbon dioxide (CO2) is a natural component of all levels of the Earth's atmosphere. Its accumulation in the lowest layers leads to the retention of the sun's heat near the surface of the planet, which is why there is a greenhouse effect. Increased CO2 in the troposphere (below 15 km above sea level), in part because of human activity contributes to global warming.
However, in the upper atmosphere is composed opposite situation. Here, the heat energy is transferred through collisions with other molecules CO2.
Such interactions induce the gas molecules radiate heat. But in extreme rarity it is lost in space, which leads to a cooling of the mesosphere (about 50-90 km above sea level) and thermosphere (90 km).
As a result of these layers, and especially the thermosphere, decrease in volume. This reduces the resistance of the atmosphere, which is experienced by the International Space Station (ISS), satellites and space debris, which move in their orbits in the border regions of the cosmos.
Any change in the resistance of the atmosphere poses a serious threat, scientists warn and remind the history of the first American space station, Skylab. When unexpectedly high solar activity warmed the upper atmosphere and their density increased, and the increased resistance of the atmosphere. Last provoked rejection station from orbit and its subsequent fall to Earth.
Scientists of the U.S. Naval Research Laboratory (NRL), Old Dominion University (Old Dominion University) and the University of Waterloo (University of Waterloo) decided to follow the dynamics of the penetration of greenhouse gases in the upper atmosphere.
The basis of the new study is based on eight-year data collected by the Canadian satellite ACE, which carried out a mission to study the various parameters of the atmosphere of the Earth.
Among the objectives was to determine the content of CO2 and carbon monoxide (CO) in the atmosphere of the Earth. These measurements were carried out by determining the efficiency of absorption of the atmosphere of our planet's sun.
Based on the new data, the researchers determined that the concentration of carbon dioxide at an altitude of about 100 km is growing at a rate of 23.5 parts per million (ppm) for ten years. This figure was 10 ppm per decade more than predicted by the mathematical model for the upper atmosphere.
The current content of CO2 at an altitude of 100 km is about 225 ppm. For comparison, the concentration of CO2 in the troposphere is growing at about 20 ppm in the decade and the current concentration of greenhouse gases in the Earth's surface is about 390 ppm.
As one of the possible reasons for the intensive distribution of carbon dioxide, researchers suggest changing circulation and mixing processes in the upper atmosphere. However, it is only a hypothesis, and scientists have yet to look into the matter.
Meanwhile, lead study author John Emmert (John Emmert) confidently stated that his team was able to find another one indisputable proof of global climate change on our planet.
With the main conclusions of the authors could find more information in the article in the journal Nature Geoscience.
Category: Astronomy and Space