The description of the developed automatic weather station for the Arctic region is presented. The station provides information to the remote user measured data such as three-component vector of wind velocity, air temperature and humidity, atmospheric pressure, precipitation parameters, solar radiation intensity, snow cover depth, and soil temperature profile (including ground surface temperature). The solution to this problem is possible only through the use of automated systems that can data acquisition, process and transmit meteorological information to a remote user in an automatic mode without human intervention.
The analyzer RGA/m is presented for measurements of mercury vapor concentrations in ambient air. It is based on a method of the atomic absorption spectroscopy. The emission source used in the analyzer is a low-pressure capillary lamp filled with mercury of natural isotope mixture. The transverse Zeeman Effect is used to split emission line into fine components. The several features of this analyzer are demonstrated.
Filtering algorithms for measurement data of the optical rain gauge OPTIOS are presented. Criteria for reducing measurement errors are considered. These errors are associated with registration of objects that are not precipitation particles, and droplets that are broken on elements of the device construction. The examples of the efficiency of proposed filtration methods for precipitation amount measurements are shown.
The results of measuring the vertical profiles of the main meteorological quantities in the atmospheric boundary layer to an altitude of 1000 m by the ultrasonic weather station AMK-03, placed on the suspension of a tethered balloon during its ascent and descent are presented in the article. Recommendations on the procedure for performing measurements using an ultrasonic weather station based on a tethered balloon are suggested.
The multilevel ultrasonic complexes created in IMCES SB RAS for automatic monitoring of meteorological and turbulent parameters in the ground atmosphere are described in this article. The results of measurements which demonstrate their opportunities for scientific research of the atmosphere are given in this article as well.
The specifics of snow precipitations characteristics measurements are considered. The paper presents the description of the method based on obtaining and analyzing precipitation particle shadow images for measurements of snow precipitations. There are results of snowfall characteristics measurements that have been registered 9 November 2015.
Conception of design of measuring and computing system for monitoring atmospheric boundary layer is proposed. The system includes: stationary measuring complex consisting of four multiple-elevation ultrasonic weather stations and mobile measuring complex consisting of transportable weather station, touch probing system of weather data profile based on unmanned aerial vehicle and also Raman scattering gas analyzer, and new modification mercury gas analyzer.
Description is presented of a portable mercury gas analyzer operating on the differential absorption method. A gas discharge capillary lamp filled with natural mercury is used as a radiation source. Transverse Zeeman effect is used to get two wavelengths.
There are specifics of use of the obtaining and analyzing precipitation particle shadow images method for the hail precipitation investigations. Descriptions of the method and operation of the new optical rain gauge measuring system are presented. There are estimations of the device capabilities and prospects of its use for measurement of hail characteristics.
It is shown that the main problem, arising when designing a stationary Raman gas analyzer intended to monitor gaseous air pollutions, is to get SRS signals of sufficient intensity. The engineering solutions are presented that provide the required sensitivity (~ 50–100 ppb). It is achieved by compressing a gas medium under analysis and gaining intensity of the exciting laser radiation.
A prototype of a stationary Raman gas analyzer with the improved sensitivity is described. The improvement is provided by using both a device for compressing analyzed gas media and a specialized effective spectral device as a part of the gas analyzer. The experimental testing of the modified Raman gas analyzer was performed in the probing of atmospheric air that confirmed the extreme sensitivity of the prototype was equal to ~ 1 ppm.
A simple and effective calibration technique for the new optoelectronic dual channel precipitation gauge (ODPG) is developed. The main result of the calibration procedure is minimization of the particle size measurement errors that depend on the optical system aberrations. Laboratory tests are carried out for generation of the calibration parameters, and for confirmation of the first theoretical evaluations performed for the device technical characteristics. The ODPG field tests (measurement of the rain parameters) demonstrate high degree of reliability of the developed design – steady operation of optical and electronic systems after transportation, efficiency of algorithms used for acquisition and processing of measurement data and calculation of the precipitation parameters.
The capability of lidar placed onboard an orbital platform to measure the atmospheric density profiles at altitudes from the Earth surface 20–100 km is investigated. The International Space Station whose Russian Segment will be equipped with one more measuring module is planned to be used as such an orbital platform. The distinguishing feature of the lidar caused by the problem being solved is the application of a laser with two working wavelengths from the UV range.
KEYWORDS: Meteorology, Ultrasonics, Data processing, Temperature metrology, Statistical analysis, Data acquisition, Environmental sensing, Humidity, Correlation function, Directed energy weapons
Numerical estimates and analysis are presented of correlations within surface layer for averaged (over periods from 1 to 20 minutes) values of meteorological parameters obtained as a result of measurement data processing. The measurement data are acquired form information-measuring system which includes several spatially separated automated ultrasonic weather stations located in Tomsk suburbs.
Results of analysis of lidar returns from clouds obtained using incoherent spatial filtering are presented in the paper. A
correspondence of multiple scattering contribution estimations from experimental data with model ones is obtained.
Calculations of clouds optical parameters and cloud's effective droplets size from experimental data are presented.
The middle IR or so-called "fingerprint" region of atmospheric gases is most attractive for multicomponent remote gas
analysis of the atmosphere. Femtosecond lidars can be applied to this purpose. In recent years compact powerful laser
systems have been developed, which emit the pulses of femtosecond duration. First of all, those are solid-state lasers
based on wide-band active media: Ti3+:Al203 (λ = 0.75-1 μm) and Cr3+:MgSiO4 (1.2-1.32 μm). Frequency conversion of
these quite promising and basic sources of super-short pulses into other spectral ranges using non-centrosymmetrical
nonlinear crystals seems to be quite attractive, especially if preserving duration of the transformed radiation. Usually to
overcome the problem middle IR femtosecond pulses are generating with two- or three-stage low efficiency frequency
converters with nonlinear crystals. High efficiency middle IR semiconductor crystals are not suitable for one-stage
generation because high optical loss at near IR.
This study was aimed at search and investigation of nonlinear crystals, in which effective single-stage optical parametric
oscillators. The investigation includes estimation of phase- and group-velocity matching conditions, phase-matching
spectral and angular widths, and potential efficiencies. The possibilities of using a hyper broadband nonlinear-optical
frequency converter of femtosecond pulse radiation for design of multicomponent mixture analyzers are investigated.
The method of broadband lidar sensing of atmospheric gases by the DOAS-technique (Differential Optical Absorption
Spectroscopy) is described. The numerical simulation of DOAS sensing of atmospheric gas components using the
frequency-converted femtosecond radiation is carried out.
The possibilities of using a hyperbroadband nonlinear-optical frequency converter of femtosecond pulse
radiation for design of multicomponent mixture analyzers are investigated. Key elements of frequency converters are
new bi-axis nonlinear crystals where the conditions of phase and growth velocity matching are fulfilled simultaneously.
The method of broadband lidar sensing of atmospheric gases by the DOAS-technique (Differential Optical Absorption
Spectroscopy) is described. The numerical simulation of DOAS sensing of atmospheric gas components using the
frequency-converted femtosecond radiation is carried out.
Results of application of incoherent spatial filtering for structure analysis of lidar returns from clouds are presented. The
revolver disk with a set of the spatial filter windows provides multiple-field-of-view of the receiver system. There is an
agreement between data recorded and model estimates considering the power contribution of doubly scattered
component due to diffraction of the sounding radiation in a droplet cloud.
The physical properties of pure GaSe and the crystals doped with 0.01÷3% Al, In, Te, and S have been observed comparatively to reveal the potentials for frequency conversion of laser emission. It has been shown that GaSe:S(greater than or equal to 3%) is the most promising material for practical applications.
The wide-angle image device has 360-degree horizontal and 180-degree vertical viewing angles and allows to
observe the all-sky in real time. The all-sky image, transformed to a television signal by means of CCD camera,
enters onto input of PC's capture card and is digitized. Record of video signal is carried out with frequency at 1 frame
per sec. The size of captured video file varies and it depends on duration of light time of day and the window size of
the video. In case of addition to the given data of the information about temperature, humidity, and pressure of air,
the full data about weather in the specific place of the specific district for any time moment of any day will be
received and kept. This database can be used for cloud cover analysis, atmospheric research, pollution monitoring,
plume research, UV prediction, and in general meteorology.
Technical potentialities of incoherent spatial filters for analyzing the brightness function of a scattering volume in the lidar observation plane are discussed. Such an analysis allows one to receive additional information on the multiply scattered component of a lidar signal. To this end, incoherent spatial filters limiting the receiving flux of a scattered radiation in the receiving objective focal plane are used. It is shown, however, that the potentialities of this analysis are limited.
A possibility of live fringe-pattern phase restorative by means of estimates of separate lines or sections of interferogram is submitted. It is possible if the phase is accepted the monotonous function in each section of interferogram. Thus, realization of on-line interferogram demodulation is possible and, besides, the fringe-pattern vibration effect is reduced.
A number of parameters were suggested for comparison potentialities of airborne and spaceborne laser sounding of atmosphere, hydrosphere, and underlying surface. These parameters were grouped in accordance with the properties that are determined by characteristics of the vehicle applied, lidar parameters, characteristics of both the lidar and the vehicle those simultaneously influence on monitoring parameters, the sounded object and environment, an information obtained and its preliminary processing, exploitation characteristics and cost of both the lidar and the vehicle. On the base of these parameters the qualitative comparative analysis has been carried out for these two kinds of laser sounding. Their merits and demerits have been considered having in mind that both sounding technologies correlate well.
Probable sources of measurement errors in ranging Earth surface with laser rangefinders and altimeters from on board space vehicles are considered. The results of ranging of the ocean surface with BALKAN Russian lidar are presented as an example.
Two laser pointers, the prototypes of which have been developed at the Institute for Optical Monitoring SB RAS, are presented. These are the laser pointer for tunnel driving and the laser pointer for lumbering. The peculiarities of their operation under industrial conditions are considered.
A possibility of restoration of live fringe-pattern phase by means of estimation of separate sections of interferogram is considered. It is possible if the phase is a monotonous function in any section of interferogram. Doing so, on-line interferogram demodulation is realized and, besides, the fringe-pattern vibration effect is reduced.
Limitation of a received elastic scattering flux in the image plane of a scattering volume by spatial filters is a means of analyzing the spatial and power characteristics of a lidar signal. This analysis is of particular use with a lidar for studying optically dense aerosol objects. Special features of incoherent spatial filters and the association of the filter parameters with the performance of a lidar transceiver system are considered. Factors limiting the spatial filter operation, including the sounding beam divergence and spatial and frequency spectrum limitation by an optical receiving system, are examined. The latter two are most essential.
It is represented equations, which define movement of crossing points trajectory of an optical airborne lidar axis with plane surface at fixed and basic coordinate system. On forming of a cone scanning movement trajectory is cycloid and at plane scanning is sinusoid. Functional dependencies to representing density distribution of spots on a surface are obtained graphically. This density distribution depends on: sensing parameters (repetition frequency of laser pulses), scanning parameters (frequency of scanning and deflection angle), flight (flying altitude and velocity).
Separation capability of singly and multiply scattered components in a lidar receiving system based on the use of spatial filtering of lidar returns is considered. A calculation example for a return power density is shown. A procedure for determination of a multiple scattering spot parameter is described. Experimental results of sounding the clouds are presented. Various instrumental realizations of the spatial filters for the practical use in elastic scattering lidars are discussed.
Refined data of spaceborne sensing of the Earth's surface with the BALKAN lidar in the spring of 1996 are presented. The lidar operated in the mode of orientation of the orbital coordinate system (calculated), in which the lidar optical axis was oriented near the nadir. Measured, Dm(f), and calculated, Dc(t), distances of the ocean surface are compared for sensing sessions examined. In each session the difference (Delta) D(t) equals Dm(t) - Dc(t) had different signs and slopes with respect to the zero line, different systematic biases, and weak oscillations. With consideration of telemetry report on the oscillations of the axes of the fixed station coordinate system about the reference orbital coordinate system, several possible reasons for the oscillations of the difference (Delta) D(t) are analyzed. In addition to the oscillations of the axes of the fixed station coordinate system, the effect of wind- driven ocean waves is evaluated.
For lidar receivers, spatial filtration problems with separate recording of the multiply backscattered flux incident at different angles relative to the optical axis of the receiving lens are considered. Beam separation is performed with spatial filters selecting image fragments within the lidar receiver field of view, which greatly exceeds the transmitted beam divergence. Various instrumental realizations of spatial filter-separators are examined, such as multielement photodetectors with concentric rings, multifiber and refractive separators, and changeable diaphragms. Possibilities and peculiarities of simultaneous and sequential recording of image fragments are considered.
The problems of the polarization lidar transceiver optimization are considered. The basic features and the optimization criteria of lidar polarization units are presented and the comparative analysis of polarization units is fulfilled. We have analyzed optical arrangements of the transmitter to form the desired polarization state of sounding radiation. We have also considered various types of lidar receiving systems: (1) one-channel, providing measurement of Stocks parameters at a successive change of position of polarization analyzers in the lidar receiver, and (2) multichannel, where each channel has a lens, an analyzer, and a photodetector. In the latter case measurements of Stocks parameters are carried out simultaneously. The optimization criteria of the polarization lidar considering the atmospheric state are determined with the purpose to decrease the number of polarization devices needed.
Some peculiarities in ranging with the space-based lidar BALKAN of the Earth surface are considered for two modes of the space station MIR orientation, which were used during measurement experiments in 1995 - 1996, and some results, that were presented earlier, are refined. Ranging of the ocean surface, which considered as reference at the first measurement stage, allows one to estimate a contribution of various sources to the measurement accuracy. The probable causes of the systematic difference between the values of slant range measured with the lidar and ballistic calculated data on range are discussed.
Different lidar receiving objects (three types of refractors, two reflectors, three refractor-reflectors, and two multicomponent objectives) have been analyzed using some generalized performance criteria. The method proposed for making a comparison based on the diagram, involving the efficiency factor and overall dimensions of the objective, enables one to choose an optimal objective according to the proposed factor of the relative efficiency or the minimal longitudinal dimension (at the same light diameter). From its point of view, in the order of increasing longitudinal dimension, the Mangene objective, the Fresnel lens, the multicomponent objective, and the Cassegrain objective are most compact, respectively. However, the Mangene objective has the smallest factor of relative efficiency.
We consider here some peculiarities in ranging with a space- based lidar 'Balkan-1' of the ocean surface for two modes of the space station 'Mir' orientation used during lidar measurement sessions. To demonstrate the peculiarities we have analyzed regular and random fluctuations of the lidar optical axis position in space that occurred in the measured sessions conducted. Analysis made allows us to discuss possible causes of the systematic difference between the ballistic calculated data on range and the values of slant range measured with the lidar in both modes of the station orientation.
In this paper we present preliminary results of measurements carried out with a Russian spaceborne lidar `Balkan' installed onboard the orbiting station `Mir', which is operated here since August 1995. This lidar is the first spaceborne lidar operated on a routine basis. We present here the basic specifications of the lidar and the orbiting station that may affect the lidar measurement results. We also consider some methodological aspects concerning the arrangement of the spaceborne experiments along with the analysis of some results on sounding the ocean surface, cloud fields, and the land obtained in different regions of the Earth and under different illumination of its surface, including sunlight and moonlight.
In this paper we present a description of an instrumentation complex developed for ground support and testing of the spaceborne lidars of 'BALKAN-1' type. The whole cycle of ground tests includes final technological tests prior to formal acceptance of the device from a manufacturer, input control preceding its assembling onboard the spaceborne module 'SPEKTR' of the orbiting station 'MIR', as well as its final tests before launch at a launch site.
Gennadii Matvienko, Vladimir Zuev, Vitalii Shamanaev, Grigorii Kokhanenko, Alexander Sutormin, Arkadii Buranskii, Stanislav Belousov, Alexander Tikhomirov
A number of automatic satellites are used for remote sensing of the Earth's surface and the atmosphere. Such space platforms have a main role in monitoring of the planet. Therefore, the developmentof spaceborne lidars for automatic space platforms is expedient. In Russia, the largest space platform was launched twice, first as the satellite "KOSMOS-1870" (1987) and second as the stationi 'ALMAZ-l" (1990). A number of instruments, including radars, rediometers, spectral optoelectronic devices were installed onboard this platform. All of them are very essential and effective for remote sensing of the Earth's surface. At present the work is underway on extension of the capabilities of the platform to improve its parameters and to increase the number of employed hardware intended, first of all, for remote sensing of the atmosphere and ocean surface. The Institute of Atmosperic Optics in collaboration with the Scientific-Production Association "Mashinostroenie" and the Russian Research-Technology Institute of Spaceborne Instrumentation are developing a new spaceborne lidar "BALKAN-2" to install at this platform. In this case the platform itself is known as "ALMAZ-lB" (see Fig. 1) and its improved specifications are the following:
In this paper we describe the first Russian spaceborne single frequency aerosol lidar. This lidar was especially designed for studying the cloud formations and the Earth's surface from space and it is planned now that it will be installed onboard the `Spektr' modulus of the orbiting Russian station `Mir'. The construction of the lidar consists of a transmitter-receiver, electronic system of data acquisition and transmission, and the control keyboard. This lidar has undergone the full cycle of ground tests as a part of the whole modulus `Spektr' and now it is ready for launch.
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