Monthly Average Values Research Articles

Estimation of the Turbulence and Regular Refraction Effects on Laser Beam Parameters in the Atmospheric Boundary Layer: Part 1, Coherence Length and Turbulent Broadening

The coherence length and the degree of broadening of a laser beam under the turbulence effect are estimated from the results of remote acoustic sounding of the atmospheric boundary layer with a Volna-4M sodar. The daily average profile of the coherence length in different seasons is considered. Corrections to the effective radius of a laser beam due to turbulence and the monthly average values of these corrections are calculated. A noticeable excess of the possible broadening of the laser beam in winter above that in summer was found.

Estimation of Surface Water Vapour Density and Its Variation with Other Meteorological Parameters Over Owerri, South Eastern, Nigeria

In this paper, the monthly variation of Surface Water Vapour Density (SWVD) with meteorological parameters of monthly average daily mean temperature, relative humidity, surface pressure, cloud cover and sunshine hours during the period of sixteen years (2000 – 2015) for Owerri (Latitude 5.48°N, Longitude 7.00°E, and 91m above sea level) were investigated. The daily variation of surface water vapour density for the two distinct seasons considering two typical months in each during the period of year 2015 was examined. The results showed fluctuation in the amount of surface water vapour density in each day of the month for the period under investigation. The monthly average daily values indicated that the surface water vapour densities are greater during the raining season than in the dry season. It was observed that the maximum average value of surface water vapour density of 21.002gm-3 occurred in the month of June during the raining season and minimum value of 14.653gm-3 in the month of January during the dry season. The highest value of surface water vapour density was observed on 9th May, 2015 and the lowest on 14th January, 2015. The comparison assessment of the developed SWVD based models was carried out using statistical indices of coefficient of determination (R2), Mean Bias Error (MBE), Root Mean Square Error (RMSE), Mean Percentage Error (MPE), Nash – Sutcliffe Equation (NSE) and Index of Agreement (IA). The developed multivariate correlation regression model that relates temperature and relative humidity with R2=99.9% MBE=0.1259 RMSE=0.1462 MPE=-0.6739 NSE=99.8402% and IA=99.9611% was found more suitable for surface water vapour density estimation with good fitting and therefore can be used for estimating surface water vapour density in the location under investigation and region with similar climatic information. The results of the descriptive statistical analysis revealed that the surface water vapour density, mean temperature, relative humidity, cloud cover and sunshine hours data spread out more to the left of their mean value (negatively skewed), while the surface pressure data spread out more to the right of their mean value (positively skewed). The surface water vapour density data have positive kurtosis which indicates a relatively peaked distribution and possibility of a leptokurtic distribution while the mean temperature, relative humidity, surface pressure, cloud cover and sunshine hours data have negative kurtosis which indicates a relatively flat distribution and possibility of platykurtic distribution.

Improving urban air quality in China: investigation and control measures of PM2.5, PM10, NO2 and SO2 in air

In recent years, the quality of urban atmospheric environment in China has caused widespread concern in the whole society. Improving air quality has become a major content of air pollution prevention and control in China. To do a good job in atmospheric prevention and control, we must investigate and analyze the sources of major atmospheric pollutants and their pollution characteristics firstly. With the acceleration of urbanization, the air pollution situation in Jinan city has become an environmental problem that people are particularly worried about. Based on the monitoring data of Jinan atmospheric environment, this paper analyzed the monthly average concentration values of PM2.5, PM10, NO2 and SO2 in Jinan City from 2015 to 2017. Meanwhile, the main reasons for the air pollution in Jinan City were clarified in detail. Finally, air pollution control strategies were proposed corresponding the aspects of pollution sources, topography and meteorological conditions, rational planning, environmental supervision capabilities, environmental awareness, and practical treatment technologies in Jinan City. These measures can provide a theoretical basis for relevant leading departments to build a beautiful city.

ASSESSMENT OF SOIL EROSION USING FOURNIER INDEXES TO ESTIMATE RAINFALL EROSIVITY

Soil erosion is one of the most extensive processes of land degradation around the world and its estimation is useful for spatial planning and policy makers for starting to remedy susceptible areas. For the moment, there is no single accepted calculation method, but most estimations are based on the classical or modified form of the Universal Soil Loss Equation (USLE). The goal of this study was to determine USLE s parameters, with accent on the main factor -the rainfall erosivity -using a modified Fournier index, and to estimate the potential erosion, in an area using GIS techniques. The rainfall aggressiveness was analyzed based on monthly and annual average values using the Fournier's index. Until now, this issue was not studied although it affects large areas. This study is based on an area located in the north-eastern part of Romania, in a catchment of 78.83 km2, a river of 17.35 km and an elevation ranging from 137 to 720 m above sea level. A map of the annual soil erosion was developed for the study area showing small areas characterized by a very high soil loss hazard, with values between 150 and 500 t.ha-1.yr-1, indicating the necessity of intervention to limit the erosion.

Dynamic modelling and performance evaluation of a direct-expansion solar-assisted heat pump for LPG vaporisation applications

This study investigated a novel LPG vaporisation system utilising direct-expansion solar-assisted heat pump (DX-SAHPV)1DX-SAHPV is the abbreviation of “LPG vaporisation system utilizing direct-expansion solar-assisted heat pump”.1 for supplying residential gas. The DX-SAHPV applies a collector-evaporator to obtain heat energy from both solar radiation and ambient air to produce hot water to vaporise LPG liquid. It can operate in six operating modes depending on the weather and gas load conditions. In this study, a dynamic model and control strategies realising the mode switching were developed to carry out the operating performance evaluation of the system. By applying the typical meteorological year data and the gas load data of a community in Beijing, China, the performance of the DX-SAHPV was evaluated and analysed for the whole year and two selected days. The simulation results show that the system can vaporise adequate LPG liquid for the community throughout the year. The solar energy contribution accounts for approximately 68% of the total heat energy for the water heated vaporisation. It was also found that the DX-SAHP obtains average monthly values of COP ranging from 2.72 to 3.37 and solar collector efficiency varying between 93 and 152%. In addition, which mode the system operates at any time on selected days was predicted and the running time of each mode in each month was discussed.

Influence of changes in the Volga river water expenditure on water hardness and alkalinity increase in Kuibyshev refinery river intake

The chemical control department of the Kuibyshev refinery (known as KNPZ) registers a systematic increase in river water hardness and alkalinity. The increase of these values changes the reagent softening mode of clearing agents with weighted sediments. It is required to carry out a constant analysis of water alkalinity before reagent softening. The researchers collected data of average monthly values of the Volga-river water samples from Samara Hydroelectric Station, the Samara-river water samples from the Bezymyanka heat power-station, the Volga-river water samples from Kuibyshev refinery as well as hourly water samples from the same stations and compared it with the data on average daily Volga-river water discharge from Zhiguly hydroelectric power station, obtained in 2016, from July till October. The analysis of the data showed that changes of the Volga-river water discharge had no effect on the increase of water alkalinity and hardness of the KNPZ river intake.

Erythemal UV Dose Rate Spatial Distribution using Ozone Monitoring Instrument Satellite Data over Egypt

The spatial distribution of Erythemal Ultraviolet Dose Rate (EUV) at noon in mW/m2 observations gotten from the Ozone Monitoring Instrument (OMI) are presented over Egypt covering the geographical domain (22.5°–31.5°N, 25.5°–35.5°E) during twelve year from 2005 to 2016. With the end goal of mapping contour, with a spatial resolution of 1°×1° the results illustrated by monthly, seasonally and all period contour maps indicate high similarity of EUV in all years. Monthly correlation (R2) relationship between EUV and Latitude also estimated in simple linear form. High R2 was found in December and January (97%) were low one was found in July (53%). In the frame of the variability, Egypt was considered as an average area; the box-whisker plots were created for average monthly and annual values of EUV. The monthly mean of EUV values are lower in the winter months (December to February) 116.17±2.30 mW/m2 compared to those in the summer months (June to August) 282.36±2.87 mW/m2. The annual mean of EUV values are lower in 2015 (204.15±60.41 mW/m2) and higher in 2013 (213.13±60.34 mW/m2).

Erythemal UV Dose Rate Spatial Distribution using Ozone Monitoring Instrument Satellite Data over Egypt

The spatial distribution of Erythemal Ultraviolet Dose Rate (EUV) at noon in mW/m2 observations gotten from the Ozone Monitoring Instrument (OMI) are presented over Egypt covering the geographical domain (22.5°–31.5°N, 25.5°–35.5°E) during twelve year from 2005 to 2016. With the end goal of mapping contour, with a spatial resolution of 1°×1° the results illustrated by monthly, seasonally and all period contour maps indicate high similarity of EUV in all years. Monthly correlation (R2) relationship between EUV and Latitude also estimated in simple linear form. High R2 was found in December and January (97%) were low one was found in July (53%). In the frame of the variability, Egypt was considered as an average area; the box-whisker plots were created for average monthly and annual values of EUV. The monthly mean of EUV values are lower in the winter months (December to February) 116.17±2.30 mW/m2 compared to those in the summer months (June to August) 282.36±2.87 mW/m2. The annual mean of EUV values are lower in 2015 (204.15±60.41 mW/m2) and higher in 2013 (213.13±60.34 mW/m2).

Annual and seasonal variabilities in the performances of wave energy converters

Locations of wave energy converters (WECs) are, most of the time, determined in areas with the highest density of mean wave power while ignoring the temporal variabilities of the resource. The most energetic regions are, however, characterised by strong inter- and intra-annual variations of wave power that may impact the energy production and performances of devices. We investigated these influences by focusing on the generated power from three well-known WECs that reached the stage of full-stage testing: Pelamis, AquaBuOY and Wave Dragon. This evaluation was conducted in western Brittany, one of the most energetic area along the coast of France. In comparison with the available resource, the generated technical power was characterised by reduced annual and seasonal variations. These effects were particularly noticeable for Pelamis that exhibited a reduced intermittency in the energy output between the winter and summer periods. The most energetic conditions had furthermore a restricted contribution to devices power output, mainly related to events with energy periods between 10.5 and 12.5 s, and significant wave heights between 2.75 and 4.25 m. WECs performances exhibited finally strong variabilities, in winter, with monthly-averaged values of the capacity factor up to 65% for Wave Dragon.

Tarifação para equacionar os serviços de saneamento ambiental, na cidade de Sousa, no Estado da Paraíba

O objetivo deste trabalho foi propor um método para calcular e equacionar as tarifas para os serviços de saneamento ambiental do Departamento de Água, Esgoto e Saneamento Ambiental (DAESA) da cidade de Sousa-PB, utilizando uma abordagem contábil-financeira. Adotou o método dedutivo, é classificada como exploratória, descritiva e do tipo documental, apresenta um estudo de caso e utilizou uma abordagem quantitativa. Com base nos dados apresentados pelo DAESA: consumo mensal, custos operacionais, número de ligações de abastecimento por tipo de usuário e ligações de esgotamento sanitário, entre outros, foi adotada uma análise considerando o custo-volume-lucro, referente à contabilidade de custos, de forma que essa metodologia pudesse fornecer base para atualização das tarifas existentes, por meio de correções percentuais sobre as mesmas. Para atender ao Ponto de equilíbrio econômico (PEE$) calculado os valores deveriam ser ajustados em 74,9% gerando uma receita de R$ 555.397,81, para cobrir R$ 82.335,40 de custos e despesas fixas e a amortização no valor de R$ 261.258,16, que foi o valor médio mensal da dívida, considerando os cinco últimos anos das faturas emitidas da Companhia de Água e Esgotos da Paraíba (CAGEPA) contra o DAESA. Por fim, descobriu-se ser necessário aproximadamente doze anos, transferindo esse valor amortizado, em parcelas iguais, para pagamento de água tratada pela CAGEPA. É importante afirmar que embora as limitações quanto à coleta das informações, há possibilidade de importar a proposta ao DAESA, corrigindo as atuais falhas quanto à sustentabilidade econômico-financeira.

Comparison and Ranking of Steam-Turbine Installations of Thermal Power-Stations’ Power-Generating Units by Working Efficiency

Increasing the objectivity of comparison and ranking of working efficiency of steam-turbine installations of thermal power-stations' power-generating units under conditions when the accuracy of technical and economic indices (TEI) to be calculated by energy characteristics leaves much to be desired; in other words, the results of TEI analysis are far from objective, and the improvement of analysis techniques of TEI is not only actual but also necessary. Traditionally, the analysis consists of comparison of actual and normal values of TIEs. The discrepancies of these values define the reserve of thermal economy and recommendations ensuring the enhancement of working efficiency of thermal power stations (TPS). Systematic improvement of recommendations' reliability is ensured by experimental clarification of energy characteristics 4 years on average after the major repair of a power-generating unit (PGU). In time, wear leads to increasing the calculation error of rated values of techno-economic indices and amendments taking into account aging. Finally, there comes a point when a manual clarification of rated TEIs becomes economically unsuitable. In accordance with the Rules for Technical Operation, the analysis results of TEIs are needed to ensure the most economical operation of powergenerating units, the development of schedules of repair and adjustment and alignment of power-generating units, the estimation of quality of operational personnel work, and drawing up of accounts on the thermal efficiency. Personnel should solve all these problems, as well as many others, depending on the difference of the actual average monthly and approximate rated values of dozens of TEI. It is proposed, along with the methods of analysis, to apply the methods of synthesis of TEI. The methods of synthesis require overcoming the influence of difference in dimensions, the influence of interrelation of TEI, and the operating conditions of powergenerating units. The possibility for synthesis of TEI manually is practically excluded, since their bulkiness and multiplicity cause a high risk of erroneous decisions. An automated analysis and synthesis system of TEI of thermal power stations' power-generating units was developed. It provides, along with the information support of personnel, methodological support in the form of recommendations for enhancement of working effectiveness of both individual power-generating units and thermal power stations as a whole. The objectivity of these recommendations is undoubted within the framework of initial data.

Межгодовые изменения интенсивности мезомасштабных вариаций ночного свечения гидроксила в Алма-Ате

The method of digital difference filters is applied to the data analysis of SATI observations of hydroxyl nightglow intensity and rotational temperature at altitudes 85–90 km over Almaty (43°03' N, 76°58' E), Kazakhstan, in 2010–2017. We examine seasonal and interannual variations in average monthly values and standard deviations of variations with periods 0.4–5.4 hrs, which may be associated with internal gravity waves in the mesopause region. The average monthly temperature near the mesopause has a maximum in winter and a minimum in June. The average monthly intensity has an additional maximum in June. Standard deviation of mesoscale rotational temperature variations and characteristics of internal gravity waves are maximum in spring and autumn. The spring maximum of mesoscale OH emission intensity variations is shifted to June. Interannual variations and multi-year trends of OH rotational temperature and emission intensity may differ in detail. This may be connected with seasonal and long-term variations in the complex system of the photochemical processes, which produce the OH nightglow.

Epidemiological Study on Respiratory Health of School Children of Rural Sites of Malwa Region (India) During Post-harvest Stubble Burning Events

A study on effects of particulate matter fractions (PM10, PM2.5 and PM1) on health of school children was done from September 2014 to December 2015 covering one wheat and two rice crop seasons. The study was undertaken at 3 rural sites in the districts of Patiala, Fatehgarh Sahib and Sangrur (Malwa region of Punjab). The monthly average values of PM10, PM2.5 and PM1 were about 3–4 times higher than the National Ambient Air Quality Standards (NAAQS) given by Central Pollution Control Board during the crop residue burning periods. The MODIS data images of crop residue burning events confirmed the active fire operations over the region. The lung function parameters (Forced Vital Capacity, Forced Expiratory Volume in one second) of children (10–16 years) decreased with increase in particulate matter concentration while no significant effect was observed on Oxygen saturation level of children. The decrease in Forced Vital Capacity was slightly more in male subjects as compared to the female population. The sharp decrease in Pulmonary Function Test parameters during the crop residue burning period indicated the severity of the episodic burning events on the health of the children.

Impact of the ozone monitoring instrument row anomaly on the long-term record of aerosol products

Abstract. Since about three years after the launch the Ozone Monitoring Instrument (OMI) on the EOS-Aura satellite, the sensor's viewing capability has been affected by what is believed to be an internal obstruction that has reduced OMI's spatial coverage. It currently affects about half of the instrument's 60 viewing positions. In this work we carry out an analysis to assess the effect of the reduced spatial coverage on the monthly average values of retrieved aerosol optical depth (AOD), single scattering albedo (SSA) and the UV Aerosol Index (UVAI) using the 2005–2007 three-year period prior to the onset of the row anomaly. Regional monthly average values calculated using viewing positions 1 through 30 were compared to similarly obtained values using positions 31 through 60, with the expectation of finding close agreement between the two calculations. As expected, mean monthly values of AOD and SSA obtained with these two scattering-angle dependent subsets of OMI observations agreed over regions where carbonaceous or sulphate aerosol particles are the predominant aerosol type. However, over arid regions, where desert dust is the main aerosol type, significant differences between the two sets of calculated regional mean values of AOD were observed. As it turned out, the difference in retrieved desert dust AOD between the scattering-angle dependent observation subsets was due to the incorrect representation of desert dust scattering phase function. A sensitivity analysis using radiative transfer calculations demonstrated that the source of the observed AOD bias was the spherical shape assumption of desert dust particles. A similar analysis in terms of UVAI yielded large differences in the monthly mean values for the two sets of calculations over cloudy regions. On the contrary, in arid regions with minimum cloud presence, the resulting UVAI monthly average values for the two sets of observations were in very close agreement. The discrepancy under cloudy conditions was found to be caused by the parameterization of clouds as opaque Lambertian reflectors. When properly accounting for cloud scattering effects using Mie theory, the observed UVAI angular bias was significantly reduced. The analysis discussed here has uncovered important algorithmic deficiencies associated with the model representation of the angular dependence of scattering effects of desert dust aerosols and cloud droplets. The resulting improvements in the handling of desert dust and cloud scattering have been incorporated in an improved version of the OMAERUV algorithm.

Variations in Ionospheric Peak Electron Density During Sudden Stratospheric Warmings in the Arctic Region

AbstractThe focus of the paper is the ionospheric disturbances during sudden stratospheric warming (SSW) events in the Arctic region. This study examines the ionospheric behavior during 12 SSW events, which occurred in the Northern Hemisphere over 2006–2013, based on vertical sounding data from DPS‐4 ionosonde located in Norilsk (88.0°E, 69.2°N). Most of the addressed events show that despite generally quiet geomagnetic conditions, notable changes in the ionospheric behavior are observed during SSWs. During the SSW evolution and peak phases, there is a daytime decrease in NmF2 values at 10–20% relative to background level. After the SSW maxima, in contrast, midday NmF2 surpasses the average monthly values for 10–20 days. These changes in the electron density are observed for both strong and weak stratospheric warmings occurring at midwinter. The revealed SSW effects in the polar ionosphere are assumed to be associated with changes in the thermospheric neutral composition, affecting the F2‐layer electron density. Analysis of the Global Ultraviolet Imager data revealed the positive variations in the O/N2 ratio within the thermosphere during SSW peak and recovery periods. Probable mechanisms for SSW impact on the state of the high‐latitude neutral thermosphere and ionosphere are discussed.

Local TEC modelling and forecasting using neural networks

Modelling the Earth's ionospheric characteristics is the focal task for the ionospheric community to mitigate its effect on the radio communication, and satellite navigation. However, several aspects of modelling are still challenging, for example, the storm time characteristics. This paper presents modelling efforts of TEC taking into account solar and geomagnetic activity, time of the day and day of the year using neural networks (NNs) modelling technique. The NNs have been designed with GPS-TEC measured data from low and mid-latitude GPS stations. The training was conducted using the data obtained for the period from 2011 to 2014. The model prediction accuracy was evaluated using data of year 2015. The model results show that diurnal and seasonal trend of the GPS-TEC is well reproduced by the model for the two stations. The seasonal characteristics of GPS-TEC is compared with NN and NeQuick 2 models prediction when the latter one is driven by the monthly average value of solar flux. It is found that NN model performs better than the corresponding NeQuick 2 model for low latitude region. For the mid-latitude both NN and NeQuick 2 models reproduce the average characteristics of TEC variability quite successfully. An attempt of one day ahead forecast of TEC at the two locations has been made by introducing as drivers previous day solar flux and geomagnetic index values. The results show that a reasonable day ahead forecast of local TEC can be achieved.

Seasonal Difference in Water Quality Between Lake and Inflow/Outflow Rivers of Lake Taihu, China

The seasonal and spatial variation of external nutrient loading from rivers and their impact on lake water quality were analyzed in Lake Taihu, China, using the monthly monitoring data from 16 major inflow/outflow rivers and 32 observation sites in the lake. The results showed:① The average monthly values of total nitrogen (TN), dissolved total nitrogen (DTN), total phosphorus (TP), and dissolved total phosphorus (DTP) in rivers were all higher than the corresponding areas in the lake. Significant positive correlations were found between nutrient concentrations in the inflow rivers and the corresponding areas in the lake, indicating the pronounced impact of external loading on lake water. ② Remarkable seasonal variations of nutrient concentration were found both in the rivers and in the lake. The highest TN and TP concentrations in inflow rivers were 4.82 mg·L-1 (March) and 0.218 mg·L-1 (December), while the highest TN and TP concentrations in the lake were 4.13 mg·L-1 and 0.255 mg·L-1 in July. ③ Extreme rainfall events could decrease the nutrient concentration in the rivers in the short-term, but finally would increase the external loading of nutrients, and indicated disadvantages for the restoration of Lake Taihu. Our study concluded that inflow pollution showed an obvious "shaping effect" on the seasonal and spatial distribution of water quality indicators in large and shallow lakes. Additionally, the self-purification ability of lakes, wind-induced accumulation and migration of algae, as well as the sediment resuspension under the prevailing winds in different seasons, all have vital effects on nutrient concentrations and their spatial-temporal variations.

Characteristics of CO2 flux and its influence factors over winter wheat agroecosystem in the North China Plain

Using CO2 flux data of winter wheat recorded by eddy covariance system, combined with the meteorological data, we examined the diurnal variations of CO2 fluxes in four growth stages (tillering stage, overwintering stage, jointing stage and filling stage) of winter wheat in an agroecosystem of the North China Plain from 2013 to 2014. The seasonal variation of net ecosystem exchange and its relationship with meteorological factors were investigated. The results showed that the net ecosystem exchange in the whole growing season was -360.15 g C·m-2. The gross primary productivity in the whole growing season was 1920.01 g C·m-2. The winter wheat agroecosystem had strong capacity in carbon sequestration. The CO2 fluxes showed an obvious diurnal and seasonal variation characteristics in winter wheat agroecosystem. This ecosystem was a carbon source in tillering stage, while it was a carbon sink in overwintering stage, jointing stage and filling stage. The mean value of apparent initial light energy utilization was 0.03 mg CO2·μmol-1. The mean value of ecosystem production was 1.53 mg CO2·m-2·s-1 when light was saturated. The monthly average value of ecosystem respiration was 193.92 g C·m-2·month-1. The net ecosystem exchange and photosynthetically active radiation had a significant correlation in four growth stages of winter wheat. The correlations between net ecosystem exchange and vapor pressure deficit were significant in all the growth stages. There was a positive correlation between daily total net ecosystem exchange and soil temperature in tillering stage, overwintering stage and filling stage, but a negative correlation between them in jointing stage.

FEATURES OF SEA LEVEL OSCILLATIONS IN INLAND BASINS OF THE ATLANTIC OCEAN

Problem Statement and Purpose. The determination of the impact of planetary regularities not only to the entire dynamic system of the World Ocean but also on its separate regions stimulates the development of mechanisms for rational nature management in the coastal zone for various space-time scales. The aim of the work is to compare the long-term characteristics and trends of sea level variability in the inner basins of the Atlantic Ocean, to establish their seasonal features.Data & Methods. Level measurements at gauging stations of the Baltic, Black and Azov Seas which are given in the public sources were used for this research. Most of these stations have the data series in the Baltic reference system for the same time period: from 1875 to 2006 for the mean annual level and from 1977 to 2006 for the average monthly values. The correlation analysis was used to determine statistical connections, the spectral analysis was used for finding the dominant oscillations.Results. The positive trends (from 0,7 to 2,9 mm year-1) in the dynamics of the average annual sea level (1875-2006) at the eastern coast of the Baltic and the northern coast of the Azov-Black Sea basin were established for the whole period. Long-period fluctuations of the level within each sea are well correlated (0,84-0,94) and there is practically no connection between the basins. The seasonal variation in the seas being compared has an anti-phase character (correlation coefficient from -0,64 to -0,87). Sea-level fluctuations have the value from one to tens of years, with the most significant quasi-two-year and 3-5-year periods.

Decomposition and modelling of the annual cycle of meteorological variables in the Ukrainian Carpathians

Formulation of the problem. In this paper we consider some structural peculiarities of the seasonal cycle of a number of meteorological variables (air temperature, sum of precipitations, saturation deficit, relative humidity, water vapour pressure, station level and sea level pressure, wind speed) in the Ukrainian Carpathians, with the annual cycle being interpreted as a superposition of six harmonics with the period ranging from 2 months to 1 year. Data and methods. This research is based on the average monthly values of seven meteorological variables in the Ukrainian Carpathians within a standard climatological period of 1961-1990. Implicit frequencies in seasonal fluctuations were revealed and evaluated with the help of harmonic analysis method. Presentation of the main research material. A particular emphasis has been laid on the parameters of the first (annual) and second (semiannual) harmonics. It was found out that, on average, the annual harmonic explains some 87% of the total variance of the variables, while the semiannual harmonic accounts for more than 7%. It is shown that when considering seasonal fluctuations of air temperature, saturation deficit and water vapour pressure annual harmonic will suffice. Analyzing fluctuations of other meteorological variables requires a semiannual harmonic to be taken into account. Higher order harmonics (from third to fifth) are to be taken into consideration when analyzing relative humidity, sum of precipitations, station level pressure, and wind speed. The last harmonic (with a period of 2 months) does not play any significant role at all. It was found out that the seasonal cycle structure of these meteorological variables at mountain weather stations and at foothill ones differ noticeably. For some meteorological variables, namely saturation deficit, air temperature, water vapour pressure and atmospheric pressure, orographic effects that manifest in either delayed or early phase of the annual cycle with relation to altitude, have proved to be statistically significant. Phases of this harmonic are typical of meteorological variables that are directly interdependent, while variables that are inversely interdependent normally fluctuate in antiphase.