Temperature profile retrieval

The retrieval method has been used extensively for temperature profile retrieval in both the terrestrial and other planetary atmospheres. Examples of profiles obtained by this technique for Earth, Mars, Jupiter, Saturn, Uranus, and Neptune are shown in Fig. 8.2.2. Also included is a Titan profile obtained from radio occultation data. The profiles for Earth and Mars were derived from measurements obtained with the Fourier transform spectrometers carried on Nimbus 3, 4, and Mariner 9, respectively. In both cases data from the 15 ptm. CO2 absorption band were used. The profiles for the outer planets were obtained by inversion of measurements from the Voyager Fourier transform spectrometers. For Jupiter and Saturn, data from the S(0) and S(l) collision-induced H2 lines between 200 and 600 cm were used, along with measurements from the CH4 V4-band centered near 1300 cm . Because of the extremely low temperatures encountered on Uranus and Neptune, adequate signal-to-noise ratio for the retrieval of vertical thermal stmctures was obtained... 

The pressures at the tangent altitudes (representing the observation geometries) and the temperature profile (p,T), as well as die volume mixing ratio (VMR) profiles of five high priority species (O3, H20, HNO3, CH4 and N20), will be routinely retrieved in near real time (NRT). The retrieval of these parameters from calibrated spectra (Level lb data) is indicated as NRT Level 2 processor. 

The unknown of the problem consists of the profiles of temperature, pressure and VMR of the target species. The simultaneous retrieval of all these profiles, that would reduce the systematic errors on the retrieved profiles, is hot feasible due to the huge amount of computer memory required. Therefore, the adopted approach is first to retrieve pressure and temperature profiles simultaneously, then to determine the minor constituents VMR profiles individually in sequence. 

Two examples of this case are (i) the temperature profile from an autoclave, and (ii) standalone PLC-based systems. All I/Os are saved in the controller s transient memory. Neither the inputs (e.g., the operator keyboard) nor the outputs (e.g., the operator display) are retrieved from, or saved to, durable media. If the record has not been saved yet to durable media, it will be vulnerable to accidental or intentional alteration. 

One of the possible alternative methods for non-invasive temperature sensing and monitoring that is completely passive and inherently safe is microwave radiometry (MWR).. We proposed a multi-fl equency microwave radiometry as a non-invasive monitoring method of deep brain temperature and fabricated a five-band receiver system and reported its measurement performance of about 1.6 K 2o-confidence interval at 5 cm depth from the surface of a water-bath phantom with similar temperature distribution as infant s brain [6]. Because the clinical requirement is less than 1 K, further improvement of MWR system were essential for a successful hypothermia treatment. We have done a couple of actions to reduce background noise in order to obtain the better temperature resolutions of five microwave receivers and tried to retrieve the temperature profile in the phantom. This paper describes the current feasibility of the MWR system for clinical hypothermic treatment. 

Fig. 6 Retrieved temperature profile in phantom Measurement stability at 5 cm depth (assumed to be the center of infant s brain) was 0.51 °C...

On Earth the same spectral interval (from 667 cm" to 800 cm"Q is suitable for temperature retrieval in cloud-free areas (Kaplan, 1959). Indeed, this spectral region served in the first derivations of the vertical temperature profile from the Nimbus 3 meteorological satellite, and initiated a new era in weather forecasting... 

In Section 8.1 we introduce numerical retrieval methods and apply them to atmospheric parameters in general. Section 8.2 is devoted to the retrieval of atmospheric temperature profiles. A large number of different numerical techniques is now available for this task. The retrieval of information on atmospheric composition is the subject of Section 8.3. Again, a wide range of methods must be considered. Cloud parameters and the properties of suspended particulates can also be deduced from infrared measurements. This topic is treated in Section 8.4. The determination of properties of solid surfaces is discussed in Section 8.5, while processes of finding the albedo and the total thermal emission of the Solar System objects are analyzed in Section 8.6. 

Knowledge of the temperature profile is essential for an understanding of the dynamical, thermodynamical, and chemical processes occurring in an atmosphere. In addition, the atmospheric temperature must first be obtained before information on gas or particle composition can be extracted from thermal emission measurements. More effort has been devoted to the retrieval of temperature profiles than any other atmospheric parameter and, as a consequence, this problem is better understood than other inverse radiative transfer problems. Study of this subject also provides a convenient means of illustrating some of the basic concepts of vertical profile reconstruction from remotely sensed data. 

The superscript T indicates matrix transposition. S = FF is the two-point correlation matrix of the basis vectors only this parameter appears in the solution and not the basis vectors themselves. The nonlinearity of the problem is taken into account through iterative application of Eq. (8.2.8). The error covariance matrix for the retrieval temperature profile due to instrument noise propagation is... 

Another approach, widely used in remote sensing, is the relaxation method originally applied to the temperature retrieval problem by Chahine (1968). In the development of this algorithm it is assumed that measurements are available at a discrete set of wavenumbers, Vj (i = 1, m), which are associated with a set of weighting functions W(Vi, z) whose maxima are well distributed over the atmospheric levels of interest. A first estimate of the temperature profile is obtained from the relation... 

Although the basic principles of the retrieval of vertical composition profiles from infrared measurements by inversion of the radiative transfer equation are the same as the retrieval of temperature profiles discussed in Section 8.2, the composition problem is usually more difficult to deal with in practice. The optical depth at a given level in the atmosphere is determined by an integration over the optically active gas profile from that level to the effective top of the atmosphere. Calculation of the radiance at the top of the atmosphere then requires an integration of the source function over all optical depths from the lower boundary to the top of the atmosphere. Thus the desired abundance profile is embedded within a double integration. 

Bottom panel Observed and synthetic Ha profiles for HD 140283 (black 5760K, grey 5560 K). The data was retrieved from the VLT archive (observing date 2000-06-15), reduced using REDUCE and rectified using parabolic fits to the continua in adjacent orders. Notice the variable telluric features which somewhat suppress the blue wing. An effective temperature of 5560 K (best estimate of [3]) is clearly too low, 5760 K (derived from the UVES POP spectrum) too high. At a S/N of 150, observational systematic errors are thus of the order of at least 100 K. 

An ESA supported study was carried out for the development of an optimized code for near real time retrieval of altitude profiles of pressure, temperature (p, T) and volume mixing ratio (VMR) of five key species (O3, H20, HNO3, CH4 and N20) from infrared limb sounding spectra recorded by MIPAS (Michelson Interferometer for Passive Atmospheric Sounding), which will be operated on board ENVISAT-1 satellite. 

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