High-level atmospheric physics

honggarae 02/12/2022 354

Basic introduction

19 centuries ago, the people of the night airglow and aurora (part of the night sky) and other luminous phenomena in the upper atmosphere made observation. The late 19th century, people began to calculate and study high-altitude induced current and magnetic field changes by the day and ground magnetic storms and the like. The early 20th century, the study found that the ionosphere and radio wave propagation, the study of the upper atmosphere physics played a catalytic role. It also expands the study of phenomena in the upper atmosphere of the tides, sound waves, gravity waves and photochemistry. Rockets, emergence and development of satellite technology, making the physics of the upper atmosphere research has made a more rapid development. The early 1950s, found the density of the upper atmosphere with solar activity several hundred times change; also found that the presence of helium layer in the upper atmosphere. Advanced ground incoherent scatter radar and laser detection equipment such as radar, capable of long-term monitoring of multi-parameter upper atmosphere. 70 years later, launching a comprehensive exploration satellite specializes in the upper atmosphere, such as "explorers" C, D, E, and "Atmospheric satellite" (Aeros) and so on. Atmospheric exploration satellite can simultaneously measure the integrated solar radiation, atmospheric radiation, neutral components, ionic components, electric and magnetic fields of space. Through comprehensive measurements can drill a number of important multi-factor process of the upper atmosphere, such as photochemical process, various heating mechanisms, coupled neutral atmosphere and ionosphere. Upper atmospheric physical processes are mainly:

diffusion balance is the main process determines the upper atmosphere spatial distribution of each component. Atmospheric gradual transition from the uniformly mixed state of 80 km or less than 120 km to molecular diffusion equilibrium. Ni density of each fraction according to their elevation Hi decay exponentially with height Z,,

wherein ni is the height of the ingredient at ZO number density. Hi level is proportional to the atmospheric temperature and inversely proportional to the molecular weight of the component. I.e. the higher the temperature, the smaller the molecular weight, the number density of the slower decay with height. As a result, the weight of the composition more concentrated in the lower, more concentrated light component aloft. Thus, an oxygen atom becomes an important component of over 200 km in the upper atmosphere; above about 1000 km helium as the main component; and above about 2000 km is mainly a hydrogen atom. This level of the hierarchy is the main structure of the upper atmosphere, the diffusion balance is the result of gravity.

High-level atmospheric physics

energy balance solar ultraviolet radiation and X-ray excitation that the particles in the upper atmosphere, the decomposition and ionization, part of the solar radiation energy into thermal energy in the upper atmosphere. The main heat absorbing layer 100 to 200 km altitude. 200K so that the atmospheric temperature between 80 to 90 km to 200 km rapid 800 ~ 900K. After the temperature slowly gradually increases with height, close to the top of the atmosphere temperature to 500 km, and then up the temperature remains substantially unchanged.

magnetic disturbance caused by the variation of the solar wind, strong currents generated by electromagnetic induction in the upper atmosphere in the high latitudes. This current Joule's heat to form the electrical energy into heat energy, the temperature of the atmosphere region several improved. In addition, solar cosmic rays and energetic charged particles from the magnetic pole end of the injection region, can also cause an increase in the temperature region of the upper atmosphere. High atmospheric temperature vary greatly due to solar activity and magnetic disturbance caused by the (top of the atmosphere temperature), which ranges from about 600 ~ 2000K.

high molecular scale motion of the motion of the upper atmosphere has atmospheric molecular diffusion, viscous momentum transfer and molecular heat conduction and the like. Turbulence is also important in the 80 to 120-km. Macroscopic motion of the upper atmosphere has a global-scale circulation and tides, but also a period of several minutes to several hours of heavy sound wave. In the upper atmosphere, the neutral portion and the different portion ionization due to power, or different motion. However, due to the collision between the two parts of particles frequently, so the movement of the two parts of the strong interaction. Although the presence of the heat source and heat sink, driven mainly by the neutral portion of the motion, but the ions ionized ionic resistance and traction is an important part of the neutral part of the movement force.

upper atmosphere with low, sports phenomenon in the atmosphere coupling senior middle atmosphere some of them from low, middle atmosphere pass over. One of the causes of the upper atmosphere by the tides and middle stratosphere ozone in the atmosphere absorbs solar ultraviolet radiation caused. Low, middle AGWs various disturbances in the atmosphere is formed, which after upward wave energy into heat energy transmitted to the upper atmosphere, but also a heat source to promote the movement of the upper atmosphere. Some of the low, middle obscure important physical phenomena in the atmosphere can be displayed in the upper atmosphere, such as atmospheric tidal wave acoustic heavy (see atmospheric dynamics level). At this time, the upper atmosphere is equivalent to a "filter." Further, the upper atmosphere with low coupling between the middle atmosphere, also in the form of mass transfer, momentum transfer, energy transfer and other electromagnetic field.

upper atmosphere and magnetosphere coupling due to solar activity strengthen or solar flares intense magnetic disturbances caused outbreaks, often can drive the upper atmosphere of charged and neutral component ingredients do strenuous exercise together. Such high-level global dynamic processes in the atmosphere is generally caused by a few hours, than the low, middle atmosphere dynamic process much faster.

In addition, between the magnetic layer and the upper atmosphere also coupled through the transmission quality, momentum transfer, energy transfer and other electromagnetic field.