last update: 13 May 2016
Atmospheric Remote Sensing Laboratory

2. Interpretation of satellite measurements

In July, 2014 next Russian polar-orbital meteorological Spacecraft Meteor-M No2 has been launched having onboard various equipment for remote sensing of parameters of the atmosphere and the Earth's surface, including Fourier spectrometer IR Fourier-spectrometer IRFS-2 created in "Keldysh's Center" (Moscow), and the microwave scanner-sounder MTVZA-GYa.

2.1. Interpretation of satellite measurements by IRFS-2 spectrometer

Onboard infrared Fourier spectrometer IRFS-2 as a part of Meteor-M No2 spacecraft (a solar-synchronous orbit, average height of 835 km) is intended for measuring spectra of outgoing Earth radiation and ensuring needs of global and regional operational meteorology and climatology regarding receiving the following types of information: vertical profiles of temperature and humidity in the troposphere, the total content and high-altitude distribution of ozone, concentrations of minor gaseous components, temperature of underlying surface, etc.

Appearance of Fourier spectrometer IRFS-2 is given in Fig. 2.1. The principal characteristics of the device functioning now in space are presented in Fig. 2.2. These characteristics correspond to those of the best modern devices of this type. The position on the Earth's surface of areas scanning by the IRFS-2 device, the example of the measured spectra and random errors of measuring the outgoing thermal radiation of the "surface-atmosphere" system are introduced in Fig. 2.3. Fig. 2.4 demonstrates spectra of outgoing thermal radiation measured by IRFS-2 in various regions of the globe .

Interpretation of IRFS-2 measurements for retrieving profiles of atmospheric temperature and humidity was performed using algorithms and software developed in our laboratory. Atmospheric temperature profiles retrieved from IRFS-2 measurements and results of comparing those with NCEP (National Centers for Environmental Prediction) data are given in Fig. 2.5 . Similar comparison is presented in Fig. 2.6 for retrieved profiles of relative humidity.

IRFS-2 measurements give a possibility not only to perform the temperature-humidity sounding of the atmosphere but also to retrieve contents of climate-influencing atmospheric gases. Comparison of total ozone fields retrieved from IRFS-2 and OMI (Ozone Monitoring Instrument) measurement data is shown in Fig. 2.7.

2.2. Interpretation of satellite measurements by microwave scanner-sounder MTVZA-GYa

Onboard microwave scanner-sounder MTVZA-GYa as a part of Meteor-M No 2 spacecraft is intended for temperature-humidity sounding of the atmosphere and determining a number of integral parameters of the atmosphere and underlying surface. Technical characteristics and the appearence of MTVZA-GYa are given in Fig. 2.8 and Fig. 2.9, respectively.

Numerical experiments and calculations of error matrices allow to determining various parameters, namely, vertical profiles of atmospheric temperature and humidity, sea-surface wind speed, sea and land temperature, total water vapor and cloud liquid water contents. Parameters of atmosphere and underlying surface from data of real satellite measurements were retrieved using the software developed in Remote Sensing Laboratory. Comparison of temperature profiles retrieved from satellite MTVZA measurements with NCEP GFS data for 65N65S is shown in Fig. 2.10, as example. In this Fig. 2.10, the curve of natural temperature variability at different levels is also given. As it is seen, mean errors are near to 0.3 K, and RMS errors are 13 K that essentially smaller than the natural temperature variability for studied data array of satellite measurements (511 K). Retrieval mean and RMS errors for the sea-surface temperature are 0.3 K, and 2.7 K, respectively (a priori variability is 9.5 K).

Principal papers

1. Polyakov A.V., Yu.M. Timofeev, Ya.A. Virolainen, A.B. Uspensky et al. 2016: Satellite atmospheric sounder IRFS-2. Analysis of measurements of outgoing radiation spectra. Earth Observation and Remote Sensing (in press).
2. Garkusha A., et al. 2016: Analysis of possibilities for monitoring characteristics of gaseous composition of the atmosphere by IRFS-2. Earth Observation and Remote Sensing (in press).
3. Golovin Yu.M., Zavelevich Yu.M., Kozlov D.A., et al., 2015: Onboard Infrared Fourier Transform Spectrometer IFTS-2: Flight Tests and First Measurements of the Atmosphere Spectrum. Cosmonautics and Rocet Engineering, 6(85), 5158 (in Russian).

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