Wickedness: scientists have discovered how mosquitoes interfere with optical devices

© Illustration RIA Novosti . Alina Planinic a swarm of gnats over the field interferes with the range finder in the view of the artistWickedness: scientists have discovered how mosquitoes interfere with optical devices© Illustration RIA Novosti . Alina Polyanina

Scientists of the Tomsk Institute of atmospheric optics them. V. E. Zuev found that in the summer in Western Siberia mosquitoes has a significant impact on the transparency of the surface layer of the atmosphere and can reduce the efficiency of optical and infrared instruments.

On a hot summer day and on a cloudy morning, the mosquitoes, gnats, mosquitoes, midges, horseflies, flies, zhigalki (all of these insects can be grouped under one concept of «midges») are always present in the woods, fields, rivers and swamps. Scientists these insects are mainly interested in from a biological point of view: the focus is on their biology, ecology, habitat, classification, reproduction. Seek ways to reduce the negative impacts of mosquitoes on humans and animals, inventing ways of scaring and destruction. However, how a negative can affect a gnat on a work of art, still has not been evaluated. And this despite the fact that many ultra-precise instruments that study the atmosphere and space, located in Western Siberia, exactly where gnats are full.

© Fotolia / Lars Aappo mosquitoes sometimes gets to see the sky and the sunWickedness: scientists have discovered how mosquitoes interfere with optical devices© Fotolia / Lars Aappo mosquitoes sometimes gets to see the sky and the sun

The atmosphere of Earth transmits waves of different lengths are very heterogeneous: some of them are completely dissipated at the expense of particles smaller than the wavelength of the radiation (the so-called molecular scattering), part is due to the particles whose geometrical dimensions are much larger than the wavelength of the radiation (aerosol scattering). In the atmosphere there are «transparency window» — wavelengths, where the attenuation is lowest and they are able to pass through the atmosphere freely. The extinction of visible optical radiation in the «Windows of transparency» of the atmosphere depends on the amount of fine particles in the air, ice crystals, droplets of water vapor, dust, smoke. The stronger the attenuation, the worse visible in the distance, the less efficient operation of optical devices. Scientists have suggested that in the atmospheric surface layer during the warmer periods of the year the weakening of the radiation can occur additionally due to flying insects or midges.

© Photo : N. Shchelkanov, IRA WITH Rannisto the experiment. The territory of the Observatory «Background» of the Institute of atmospheric optics SB RAS. – It looks like the light source with the point location of the reflector.Wickedness: scientists have discovered how mosquitoes interfere with optical devices© Photo : N. Shchelkanov, IRA WITH Rannisto the experiment. The territory of the Observatory «Background» of the Institute of atmospheric optics SB RAS. – It looks like the light source with the point location of the reflector.

The scheme of conducted experiment is quite simple: a beam of a predetermined wavelength is directed at the reflector located at a distance (in the experiment, the scientists were firing at 950 m and 1200 m), and its reflection is recorded by the receiver. The difference in power of the outgoing and the incoming signal shows the degree of attenuation. The experiment was performed far from the city, in the forest over the grass field near the shore of the Ob river in the summer, when there is a maximum number of insects, mostly mosquitoes. The measurements occurred at a height of 2-4 metres in the ranges of mosquitoes and midges fly the most heap.

© Photo : N. Shchelkanov, IRA WITH Resistacne and the radiation receiver. Source «fires» a beam focused on the reflector, located at a distance of a kilometer, and the receiver detects the reflected beam.Wickedness: scientists have discovered how mosquitoes interfere with optical devices© Photo : N. Shchelkanov, IRA WITH Resistacne and the radiation receiver. Source «fires» a beam focused on the reflector, located at a distance of a kilometer, and the receiver detects the reflected beam.
«The mosquitoes not bothering to see when moving in the forest, but reduce the visibility of distant objects and prevent them to recognize through a telescope or binoculars, reduce the efficiency of devices operating in the visible and infrared range, – commented the results of the work of one of the authors, is the first time We were able to estimate the possible contribution of midges in the extinction of visible and infrared radiation in the absence of additional sources of atmospheric pollution in the conditions of the forests and fields of Western Siberia. The attenuation of optical radiation in surface atmospheric layer in the visible region of the spectrum (at a wavelength of 0.55-0.69 µm) accounted for 29-37 %, and in the infrared region of the spectrum greater than 4 microns – 63%. The obtained results will help us to build a more accurate optical model of the propagation of optical and infrared signals in the atmospheric surface layer, to adjust the operation of optical devices».

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