Reconstruction of the Internal-Wave Parameters in the Atmosphere from Signal Amplitude Fluctuations in a Radio-Occultati
- PDF / 1,085,870 Bytes
- 13 Pages / 612 x 792 pts (letter) Page_size
- 89 Downloads / 164 Views
nstruction of the Internal-Wave Parameters in the Atmosphere from Signal Amplitude Fluctuations in a Radio-Occultation Experiment V. Kana, *, M. E. Gorbunova, b, A. V. Shmakova, and V. F. Sofievac aObukhov
Institute of Atmospheric Physics, Russian Academy of Sciences, Moscow, 119017 Russia b Hydrometeorological Research Center of Russia, Moscow, 123242 Russia c Finnish Meteorological Institute, Helsinki, FI-00101 Finland *e-mail: [email protected] Received April 16, 2020; revised April 27, 2020; accepted June 3, 2020
Abstract—In this paper, we discuss a method for reconstructing the parameters of internal gravitational waves (IGWs) in the stratosphere from amplitude fluctuations in satellite radio-occultation observations. In the formation of radio-signal fluctuations, IGWs play the main role in these observations, while the contribution of isotropic turbulence is negligible. We consider methodological issues: (1) the choice of a model for the spatial spectrum of internal waves, (2) the derivation of relations connecting the statistical parameters of the IGW spectra and amplitude fluctuations in the approximation of a phase screen and weak fluctuations, (3) the development of a reconstruction algorithm, and (4) the estimation of possible errors. The reconstructed parameters are the outer or dominant scale and the structural characteristic of the vertical IGW spectrum, which determines the spectral amplitude in the saturation mode. The operating range covers altitudes from 28 km to the upper boundary of the tropopause. The error estimates for the reconstruction algorithm are 10– 20% for the outer scale and 20–40% for the structural characteristic. Keywords: radio-occultation sounding of the atmosphere, signal amplitude fluctuations, reconstruction of internal wave parameters DOI: 10.1134/S0001433820050072
INTRODUCTION Internal gravitational waves (IGWs) in the middle atmosphere are the main source of mesoscale fluctuations in wind and temperature, with vertical scales from several kilometers to hundreds of meters and with periods from 5 min to 10 h. They play a significant role in the energy exchange and global circulation of the atmosphere, the generation of turbulence, and mixing [1]. To include IGWs in various models of circulation and exchange in the atmosphere, it is necessary to parametrize the waves and study the global altitudinal, seasonal, and geographic distribution of these parameters. The large number of experimental studies of IGWs confirms the relevance of this problem now. Observations include measurements of temperature and wind fluctuations using probes at numerous stations from the tropics to the poles [2–6], radars [7, 8], and aircrafts [9, 10]. Global monitoring of meteorological parameters and their variations is provided by various satellite systems, such as limb spectrometers [11, 12], occultation observations of star scintillations [13– 16], and radio-occultation measurements [17–24].
Among the satellite methods, the most widespread are studies based on radio-occultation measurements of th
Data Loading...
