Gennadii G. Matvienko

Application of the method of laser-induced fluorescence

Great attention is now paid to ecology of the environment, in whic plants are of great importance. However the present methods of biophysical analysis of plant states are very labor-intensive and require a lot of time. The structure of protein-pigment complexes is known to break in different dissolvents that results in the shift of maxima of chlorophyll absorption and fluorescence bands. That is why development of methods for remote diagnostics of plants is of great scientific and practical interest. They would make it possible to determine species and state of plants rather quickly and accurately. We have developed a setup and methods for optical diagnostics of the physiological state of plants to investigate the dynamics of the fastest part of fluorescence of plants in vivo. The method of laser-induced fluorescence makes it possible to observe the level of vegetative development of living plants, as well as their state under the impact of some stress factors.

Application of laser-induced fluorescence for remote sensing of vegetation

The possibilities of applying a fluorescent lidar based on the second harmonic of a Nd:YAG laser to study vegetation under natural conditions are analyzed. The dynamics of development has been studied for several species of arboreous plants grown in West Siberia in a five-year measurement cycle. The fluorescent lidar developed has been used for identification of plant species and for investigation of fading caused by an adverse environment. It is shown that the fluorescent signal can be used for remote detection of plant stresses at earlier stages, when there are no visible symptoms. For the first time, the quantitative relations are established between the intensity of red nanosecond fluorescence and the chlorophyll concentration in needles and leaves of the most typical representatives of West Siberian arboreous plants. Fluorescent data were checked using the traditional spectrophotometric method. The spectrophotometric data and lidar measurements were used to calibrate the lidar, and this calibration has allowed the chlorophyll concentration in arboreous plants to be determined from the ratio of signals of laser-induced fluorescence.

Research of the cirrus structure with the polarization lidar: parameters of particle orientation in crystal clouds

The particles of upper clouds are ice crystals with various sizes and shapes. Under certain conditions they can be oriented in space. This circumstance leads to the significant anisotropy of light in cirrus clouds that should be taken into account when solving problems of radiation propagation through the atmosphere. Acquiring the information on parameters of particle orientation in ensembles of actual clouds is still an urgent and poorly studied problem. In this connection, we have developed a lidar technique for measuring the backscattering phase matrices (BSPM) that enables one to acquire such information. Based on processing of 450 experimentally measured BSPMs we have drawn the following conclusions: - in 90 to 95 % cases the orientation of the larger diameters of particles along the azimuth direction was observed, though in 70% of these cases the orientation was only weakly pronounced against the background of particles that had no preferred orientation in the azimuth plane. However, the backscattering coefficients for linearly polarized light can strongly depend on the orientation of the polarization plane. - the larger diameters of particles practically always lied in the horizontal plane, and in 50% cases the degree of this orientation should be recognized essential. The latter means that the extinction coefficient of such clouds should strongly depend on the angle of radiation incidence on the cloud layer.

Remote sounding of vegetation characteristics by laser-induced fluorescence

Experimental investigations of the fluorescence intensity of plants in red and ultraviolet spectral ranges induced by the laser radiation have been carried out during one year. Dependence of the quantum yield of chlorophyll a fluorescence on plant species has been established and investigated. The largest range of seasonal variations of the fluorescence intensity was observed for the deciduous trees. Seasonal variations of the florescence intensity have the tendency to insignificant variations for the coniferous trees. Application of the fluorescence method to the remote specific categorization of the plant tissue and determination of the chlorophyll content is shown to be promising.

Nondestructive methods for early detection of damage to living plants

As a result of the accomplish experiments determine, that by a method of a laser-induced fluorescence of chlorophyll it is possible to spot for cedar an early stage of the stressful factor, bound with presence in ground ≪petroleum dirt≫. In our case the laboratory researches provided learning a quantitative contents chlorophyll for plants found in normal and stressful conditions on a basis spectrophotometrical of a method. Natural measurement the observations behind dynamics of a photosynthetic state means of wood plants in vivo enable. For an estimation of this state the fluorescence of chlorophyll on wavelength 685 and 740 nm was used. The optical model of a green leaf was developed for methods of a laser-induced fluorescence of chlorophyll. A experiments series on remote research of processes violation of mineral power supply and exchange in plants is carried spent. Was considered the change of the ratios of intensity of a fluorescence of chlorophyll and carotenoids at deficiency. Was designed technique for detection infringement processes of mineral nutrition and change surveyed acidity grounds on laser-induce fluorescent responses of deciduous plants.

Space lidar Tectonica-A and ground based testing

The objective of Russian space project Tectonica-A is creation of automated lidar for studying aerosol anomalies, mainly, in the low atmosphere. By such anomaly is meant heterogeneity both of the aerosol concentration and its microphysical properties. Therefore, this project assumes that a small spacecraft will be equipped with multifrequency (wavelength range from 0.35 to 1.06 micrometers ) lidar. The lidar is aimed to investigate the aerosol fields formed during tectonic (including seismic) processes and catastrophes. Using the lidar high potentiality providing detection of local emissions in the low atmosphere. The project execution is in the stage A-B (draft design). The lidar installation is oriented to the platform MKA-200. Simultaneously with the lidar creation, the methods are developed on the basis of its mini-prototype. In October, 1999, the spatial, temporal boundaries of aerosol anomalies near Rostov-on-Don break (West Caucasus) were investigated during artificial and natural earthquakes. Simultaneously, gases show (radon, first of all) and fluctuations of atmospheric electric fields were estimated. Some correlation between aerosol, gas, and electric anomalies has been found, which underlines once again a priority of aerosol from the standpoint of remote optical monitoring of tectonic processes. Based on the obtained results, the methodological aspects of space laser sensing of aerosol anomalies are discussed in the report. The requirements to the lidar Tectonica-A and space experiments conducting are refined as well.

Fluorescence lidar system for remote monitoring of the state of vegetative cover for the purpose of its prediction

The comparative research of the chlorophyll contents for number of wood plants by traditional spectrophotometric and fluorescent laser methods is carried out.The seasonal changes of the chlorophyll sums in the sprint-summer period at coniferous and deciduous wood plants are analyzed. The supervision over changes in the chlorophyll contents in connection with a withering of needles and leafs are carried out. The experimental results are received by spectrophotometric and lidar methods of study of a course of chlorophyll seasonal dynamics and pigment complex destruction of during a withering of needles and leafs of wood plants. The results of the joint analysis have shown identity of results received essentially by various methods.

Using TEA CO2 laser radiation harmonics in helicopterborne lidar for controling leakage of toxic and dangerously explosive gases

The characteristics of a helicopter-borne lidar based on tunable TEA CO2 laser and its third harmonic designed for remote detecting the methane and ammonia leakages from pipe-lines are analyzed numerically. The spectral range near 3 micrometers is shown to be most promising for remote sensing of methane emissions. Parameters of radiation of the tunable pulse-periodic mini-TEA CO2 laser and generators of harmonics to be utilized in the helicopter-borne differential absorption lidar are estimated. Emissions of different gases intensity are analyzed for possible detectability at a distance up to 1 km. The use of the third harmonic of the TEA CO2 laser allows methane emissions from a pipe-line to be detected and measured with mean measurement error from 10 to 15% for methane concentrations varying from the background level to the explosion-hazardous one. The optimal pair and possibilities of the ammonia remote sensing on the base of the first harmonic of TEA CO2 laser was determined as well.

Siberian lidar station: the basic complex of remote laser sounding of the atmosphere

The Siberian Lidar Station created at V.E. Zuev Institute of Atmospheric Optics and operating in Tomsk (56.5° N, 85.0° E) is a unique atmospheric observatory. It combines up-to-date instruments for remote laser and passive sounding for the study of aerosol and cloud fields, air temperature and humidity, and ozone and gaseous components of the ozone cycles. In addition to controlling a wide range of atmospheric parameters, the observatory allows simultaneous monitoring of the atmosphere throughout the valuable altitude range 0–75 km. In this paper, the instruments and results received at the Station are described.

The use of frequency converter of femtosecond laser radiation in broadband lidar gas analysis of atmosphere

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.