Refinement of remote measurement methods is performed by:
– using new rafiation models of the atmosphere (direct problems in remote measurements);
– using the more adequate a priori information (new databases);
– applying optimal parametrizations of sought functions;
– optimasing measurement conditions;
– applying new retrieved methods, etc.
The following new methods were developed recently.
4.1. Ground-based measurements of ozone vertical profiles using IR-spectrometry of high spectral resolution
Ground-based measurements of direct solar IR radiation spectra with high spectral resolution allow to determining the information on vertical profiles of the content of various atmospheric gases. In particular, mesurements in ozone absorption lines content the information on the ozone content in 4–5 atmospheric layers.
Averaging kernels for the considered ground-based IR method characterizing altitude areas, the ozone content in which can be estimated, are given in Fig. 4.1. Fig. 4.2 shows the comparison of ground-based measurements of the stratospheric ozonecontent by SPbSU and data retrieved from satellite MLS microwave measurements. As it is seen from the Figure, data retrieved by ground-based and satellite methods agree within 4–6%.
4.2. Synergetic IR+MW method for measuring profiles of the ozone content
In our laboratore new synergetic ground-based remote method for measuring vertical profiles of the ozone content in wide altitude range. Numerical analysis has shown that combined measurements of IR transmittance with high spectral resolution and MW measurements of downwelling thermal radiation contain the information on the ozone content at various altitudes. IR method is informative at altitudes of 0–30 km, MW method – at 30–60 km. Combined IR and MW measurements give a possibility to retrieve the ozone content in the whole altitude range of 0–60 km.
Errors of the ozone content retrieval using only IR or MW measurements and combined measurements are shown in Fig. 4.3. Additional information for near-surface atmospheric layer can be derived from local measurements of ozone concentrations near ground.
Studies of vertical structure of the ozone content are carried out in cooperation with French scientists (G. Dufour, M. Eremenko, Laboratoire Interuniversitaire des Systemes Atmospheriques, niversite Paris-Est Creteil).
1. Virolainen Ya.A., Yu.M. Timofeyev, 2008: Retrieval of elements of the ozone vertical structure from ground-based measurements of the solar radiance with high spectral resolution. Earth Res. from Space, 2008, 3, 3–10 (in Russian).
2. Virolainen Ya.A., Yu.M. Timofeyev, 2010: Complex method for determining ozone vertical profiles to validate satellite measurements. Earth Res. from Space, 4, 61–66 (in Russian).
3. Virolainen Ya.A., Yu.M. Timofeev, A.V. Poberovskii, M. Eremenko, G. Dufour, 2015: Evaluation of Ozone Content in Different Atmospheric Layers using Ground-Based Fourier Transform Spectrometry. Izvestiya, Atmospheric and Oceanic Physics, 51, 2, 167–176.