Home – Home – Jornals – Atmospheric and Oceanic Optics 2026 number 3

Air pollution modelling in mountainous regions is a relevant challenge due to the complex interaction of topography with atmospheric dynamics and uncertainty in emission data This paper presents the results of atmospheric pollution modeling for carbon monoxide (CO) in complex mountainous terrain, using the Kislovodsk region as a case study. The study used the mesoscale meteorological model WRF and the chemical transport model CHIMERE. The results were validated against instrumental measurements carried out at the High-Mountain Scientific Station of A.M. Obukhov Institute of Atmospheric Physics, Russian Academy of Sciences. It is shown that refining the EMEP emission database by incorporating local features of the road network (density and road types) and their daily/weekly dynamics allows the spatial distribution of pollution sources to more closely approximate the actual layout of the region's road network, and also improves the accuracy of reproducing the daily cycle of CO concentrations. An experiment was conducted to quantitatively assess the contribution of orographic factors to the overall pollution level. It was established that the complex terrain of the region accounts for 20-50% of the average CO concentration level, creating zones of pollutant accumulation and dispersion. Statistical analysis demonstrates satisfactory agreement between the modeling results and observational data. The study confirms the feasibility and effectiveness of the WRF-CHIMERE modeling system in monitoring and analyzing atmospheric air quality in resort regions with complex topography. The results can serve a foundation for fundamental and applied scientific research aimed at studying the mechanisms behind the formation of periods with adverse environmental conditions. The air quality modeling can be used by local government authorities for such tasks as urban planning, optimization of road networks, and the development of recreational areas taking into account orographic conditions, as well as for improving regional environmental monitoring systems.

Harmful algal blooms pose a serious threat to the ecology of coastal waters. Their timely detection is a crucial task in environmental monitoring. Optical spectrofluorimetry may be a promising approach in this field. The subject of this scientific work is the study of normalized fluorescence temperature curves (NFTC) as reference features of hazardous microalgae and confirmation of the possibility of identifying the genera of hazardous microalgae under study with their help. NFTC were obtained in laboratory experiments with microalgae monocultures under controlled conditions with registration of fluorescence spectra during linear heating (20-80 °C). Verification was carried out by means of cluster analysis using the principal component analysis (PCA). The study has shown that NFTC demonstrate stable genus-specific patterns, making it possible to distinguish microalgae at the genus level with an accuracy of 90.91%. The use of PCA (3 principal components explaining 94.22% of the variance) eliminates clustering errors caused by multicollinearity of the original features. The highest classification accuracy is achieved for Heterosigma akashiwa (100%), the lowest - for Pseudo-nitzschia (86.15%) due to intrageneric similarity of NFTC. The study shows the need to expand the catalog of standards to enhance the statistical significance of the results.

Effects of heat flux during the early spring plankton vegetation period in Lake Dolgoe (Belarus) were studied based on a coupled mathematical model which reproduces thermohydrodynamic and hydrobiological processes in a freshwater lake. Calculations were performed under different values of heat flux which interacted with the water surface. The simulations showed the following: with increased insolation, which contributed to the intensive spread of inflow waters with a low content of organic matter into the lake, the concentrations of plankton decreased from the surface to some depth, and below that depth they again increased. It was also found that those depths were different for phyto- and zooplankton in the deepest part of the lake (18 m and 15 m, respectively).

This work continues the study of the possibility of using the laser fragmentation/laser-induced fluorescence (LF/LIF) method for the remote detection of nitrocompounds (NC) and organophosphorus compounds (OPC). A method for the combined detection of surface traces of NС and OPС is discussed. It is experimentally shown that exciting laser radiation wavelength of 246.824 nm, falling in the region of overlapping rotational lines of γ(0, 2) and γ(0, 0) bands of NO and PO absorption spectra, can be used for the simultaneous excitation of fluorescence of NС and OPС photofragments. To improve the noise immunity of the LF/LIF detection method, it is proposed to use a wavelength of the probing laser radiation in the range of overlapping γ(0, 2) and γ(1, 1) bands of the absorption spectra of NO- and PO-fragments in excited vibrational states after fragmentation. The resulting intense anti-Stokes γ(0, 1) and γ(1, 0) fluorescence bands are located in the spectral range 235-240 nm and do not overlap with the spectra of broadband Stokes fluorescence of surface materials bearing traces of NС and OPСs. The results can be used in the development of a universal system for the simultaneous detection of surface traces of explosives and toxic substances by LF/LIF method.

Solar-induced fluorescence is an indicator of plant photosynthetic activity that shows promise for monitoring ecosystem productivity on a global scale. The paper presents estimates of the photosynthetic activity for the main phytocenoses of southern Western Siberia (grasslands, deciduous and light coniferous forests, croplands and wetlands) based on TROPOMI satellite data for the period 2018-2024. Using ERA5-Land reanalysis data and products obtained from MODIS and CERES sensor measurements, we investigated the correlations between solar-induced fluorescence and key environmental temperature and moisture parameters, vegetation indices, and photosynthetically active radiation, as well as directly between these features themselves (spatial resolution - 0.05°, temporal resolution - 1 month). The presented results describe the specifics of these relationships both for the main phytocenoses of the entire target region and their latitudinal variability for grasslands and deciduous forests.