Lidar measurements of air density in the middle atmosphere. Modeling of potential capabilities in spectrum UV region

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   Errors in lidar measurements of the air density in the middle atmosphere
   are analyzed. A lidar was placed on board the ISS. A solid-state Nd: YAG
   laser operating at the 3rd and 4th harmonics with wavelengths of 353 and
   266 nm was used as a lidar transmitter. Calculations were performed for
   the lidar with reasonable parameters: pulse energy 0.4 (353 nm) and 0.2 J
   (266 nm), pulse repetition frequency 20 Hz, accumulation time 60 s, radius
   of the receiving mirrors 0.3 and 0.5 m, field of view of the receiving
   telescope 1 and 0.1 mrad, filter bandwidth 0.5, 1, and 10 nm, and spatial
   resolution 1 km. The results showed, that radiation at the wavelength of
   353 nm can cover the altitude range, on average, from 75 km at night and
   from 55 km in the daytime to 10 km depending on the parameters of a lidar
   with 10% measurement errors (calculations were not carried out below 10
   km). When operating with the radiation at 266 nm for 10% measurement
   error, the sensing range can be expanded to the upper mesosphere at 90 km
   and penetrate deeper into the atmosphere down to 38 km. Thus, the use of
   two harmonics allows the altitude range of air density measurements from
   the ISS to be expanded from 90 km down to the troposphere.