The role of renewable energy sources in the Polish power system is growing. The highest share of installed capacity goes to wind and solar energy. Both sources are characterized by high variability ...of their power output and very low dispatchability. Taking into account the nature of the power system, it is, therefore, imperative to predict their future energy generation to economically schedule the use of conventional generators. Considering the above, this paper examines the possibility to predict day-ahead wind power based on different machine learning methods not for a specific wind farm but at national level. A numerical weather prediction model used operationally in the Institute of Meteorology and Water Management–National Research Institute in Poland and hourly data of recorded wind power generation in Poland were used for forecasting models creation and testing. With the best method, the Extreme Gradient Boosting, and two years of training (2018–2019), the day-ahead, hourly wind power generation in Poland in 2020 was predicted with 26.7% mean absolute percentage error and 4.5% root mean square error accuracy. Seasonal and daily differences in predicted error were found, showing high mean absolute percentage error in summer and during daytime.
Kraków, Poland, is a city with poor air quality, located in the large Wisła (Vistula) valley, and affected by a foehn wind from the Tatra Mountains. We analyzed 14 long episodes of the foehn from the ...periods Sep 2017 - Apr 2018 and Sep 2018 - Apr 2019. Data used included measurements of PM
10
(i.e. particulate matter with an aerodynamic diameter up to 10 µm) concentrations) concentrations, air temperature and relative humidity, wind speed and direction from ground stations and mast measurements up to 100 m a.g.l., along with model analysis results. A non-operational configuration of the AROME CMC (the Application of Research to Operations at Mesoscale canonical model configuration) 1 km x 1 km was applied. A conceptual model concerning the impact of a foehn on urban air pollution was developed. The occurrence of a particular effect of a foehn on the PM
10
spatial-temporal pattern depends on its mode of transfer through the city: a. a foehn flows above the valley where a strong cold air pool and a return flow can be found; b. a foehn enters the valley from the eastern, wider part or from the valley top and destroys the cold air pool; c. gravity waves generated by a foehn are strong enough to enter the western narrower part of the valley and cause large spatial differences in turbulence parameters within the city. The first transfer mode worsens air pollution dispersion conditions throughout the city and leads to large increases in PM
10
levels (from below 50 to 150-200 µg⋅m
−3
), the second mode improves dispersion and leads to large decreases in PM
10
levels (from 150-200 to below 50 µg⋅m
−3
) throughout the city, and the third generates large spatial differences in PM
10
levels (50-70 µg⋅m
−3
) within the city. There is no single effect of a foehn on air pollution dispersion conditions.
In this article, a machine‐learning‐based tool for calibrating numerical forecasts of near‐surface air temperature is proposed. The study area covers Poland representing a temperate type of climate ...with transitional features and highly variable weather. The direct output of numerical weather prediction (NWP) models is often biased and needs to be adjusted to observed values. Forecasters have to reconcile forecasts from several NWP models during their operational work. As the proposed method is based on deterministic forecasts from three short‐range limited‐area models (ALARO, AROME and COSMO), it can support them in their decision‐making process. Predictors include forecasts of weather elements produced by the NWP models at synoptic weather stations across Poland and station‐embedded data on ambient orography. The Random Forests algorithm (RF) has been used to produce bias‐corrected forecasts on a test set spanning one year. Its performance was evaluated against the NWP models, a linear combination of all predictors (multiple linear regression, MLR) as well as a basic Artificial Neural Network (ANN). Detailed evaluation was done to identify potential strengths and weaknesses of the model at the temporal and spatial scale. The value of RMSE of a forecast obtained by the RF model was 11% and 27% lower compared to the MLR model and the best‐performing NWP model respectively. The ANN model turned out to be even superior, outperforming RF by around 2.5%. The greatest improvement occurred for warm bias during the nighttime from July to September. The largest difference in forecast accuracy between RF and ANN appeared for temperature drops inApril nights. Poor performance of RF for extreme temperature ranges may be suppressed by training the model on forecast error instead of observed values of the variable.
As forecasts of 2‐m air temperature produced by numerical weather prediction (NWP) models are often biased, they need to be post‐processed to match observed values. During their work forecasters compare forecasts from different NWP models mainly on the basis of their experience. For that purpose, a machine‐learning‐based method to combine forecasts of three models is proposed and thoroughly validated. It reduces forecast error throughout the year by around 25%.
Winter smog episodes are a severe problem in many cities around the world. The following two mechanisms are responsible for influencing the level of pollutant concentrations: emission of pollutants ...from different sources and associated processes leading to formation of secondary aerosols in the atmosphere and meteorology, including advection, which is stimulated by horizontal wind, and convection, which depends on vertical air mass movements associated with boundary layer stability that are determined by vertical temperature and humidity gradients. The aim of the present study was to evaluate the performance of an unmanned aerial vehicle (UAV)-based measurement system developed for investigation of urban boundary layer dynamics. The evaluation was done by comparing the results of temperature, relative humidity, wind speed and particulate matter fraction with aerodynamic diameter below 10 μm (PM
) concentration vertical profiles obtained using this system with two reference meteorological stations: Jagiellonian University Campus (JUC) and radio transmission tower (RTCN), located in the urban area of Krakow city, Southern Poland. The secondary aim of the study was to optimize data processing algorithms improving the response time of UAV sensor measurements during the ascent and descent parts of the flight mission.
Prediction of spatial and temporal variability of air temperature in areas with complex topography is still a challenge for numerical weather prediction models. Simulation of atmosphere over complex ...terrain requires dense and accurate horizontal and vertical grids. In this study, verification results of three configurations of the Aire Limitée Adaptation Dynamique Développement International High-Resolution Limited Area Model (ALADIN-HIRLAM) numerical weather prediction (NWP) system, using two different horizontal and vertical resolutions and applied to the Polish Western Carpathian Mountains, are presented. One model of the ALADIN-HIRLAM NWP system is tested in two horizontal and vertical resolutions. Predicted air temperatures are compared with observations from stations located in different orographies. A comparison of model results with observations was conducted for three cold season intervals in 2017 and 2018. Statistical validation of model output demonstrates better model representativeness for stations located on hill and mountain tops compared to locations in valley bottoms. A comparison of results for two topography representations (2 × 2 km and 1 × 1 km) showed no statistically significant differences of root mean square error (RMSE) and bias between model results and observations.
This study presents the assessment of the quantitative influence of atmospheric circulation on the pollutant concentration in the area of Kraków, Southern Poland, for the period 2000–2020. The ...research has been realized with the application of different statistical parameters, synoptic meteorology tools, the Random Forests machine learning method, and multilinear regression analyses. Another aim of the research was to evaluate the types of atmospheric circulation classification methods used in studies on air pollution dispersion and to assess the possibility of their application in air quality management, including short-term PM10 daily forecasts. During the period analyzed, a significant decreasing trend of pollutants’ concentrations and varying atmospheric circulation conditions was observed. To understand the relation between PM10 concentration and meteorological conditions and their significance, the Random Forests algorithm was applied. Observations from meteorological stations, air quality measurements and ERA-5 reanalysis were used. The meteorological database was used as an input to models that were trained to predict daily PM10 concentration and its day-to-day changes. This study made it possible to distinguish the dominant circulation types with the highest probability of occurrence of poor air quality or a significant improvement in air quality conditions. Apart from the parameters whose significant influence on air quality is well established (air temperature and wind speed at the ground and air temperature gradient), the key factor was also the gradient of relative air humidity and wind shear in the lowest troposphere. Partial dependence calculated with the use of the Random Forests model made it possible to better analyze the impact of individual meteorological parameters on the PM10 daily concentration. The analysis has shown that, for areas with a diversified topography, it is crucial to use the variability of the atmospheric circulation during the day to better forecast air quality.
Etyka w pracy audytora wewnętrznego Krawczyk, Marzena; Sekuła, Piotr
Annales Etyka w Życiu Gospodarczym,
05/2008, Volume:
11, Issue:
2
Journal Article
Peer reviewed
Open access
Internal audit provides an independent and objective opinion to the Board
on risk management,
control and governance, by measuring and evaluating their effectiveness in achieving an organisation’s
...agreed objectives. It also provides an independent and objective consultancy service to help line
management improve the organisation’s processes.
Internal auditors should respect in their work some ethical rules, especially these included in
the Code of Ethics formed by the IIA. This code is intended to clarify the standard of conduct expected
from all members of the internal audit unit. The main four principles that should be observed are
as follows: integrity, objectivity, competency and confidentiality
Being ethical in internal audit is necessary in order to win the trust of the environment in which
auditors work. However, declaring one’s readiness to respect the Code of Ethics is not enough. Much
more important is to implement and comply with given rules in carrying out audit duties.
Groundwater samples were evaluated throughout Turkana County (Kenya, East Africa) while looking for drinking water sources. Some samples showed high concentrations of fluoride with values in the ...range of 0.15–5.87 mg/L. Almost 50% of the samples exceeded the WHO and Kenyan potable water standard guideline value of 1.5 mg/L for drinking water quality. The hydrogeochemical studies revealed that the dominant cation in water is Na
+
and the dominant anion is HCO
3
−
resulting in Na-HCO
3
type of groundwater, followed by Ca/Mg-HCO
3
or Na-SO
4
and Na-Cl in a few cases. Speciation modelling revealed that the groundwater is undersaturated with respect to gypsum and anhydrite, mostly undersaturated with respect to fluorite (6 samples are at equilibrium), and supersaturated or at equilibrium with respect to calcite (CaCO
3
). Precipitation of calcite favours the dissolution of F-rich minerals in the alkaline medium. Simultaneously, groundwater is enriched with sodium and bicarbonate, probably as a result of chemical weathering of Na-feldspar. Investigated groundwater can be presumably used for drinking purposes from 17 wells, but a detailed investigation of other trace element concentrations is necessary.
The Metabolic and Bariatric Surgery Chapter of the Association of Polish Surgeons (Polish acronym: SCMiB TCHP) is a Polish specialist scientific society representing bariatric surgeons as well as ...specialists from other disciplines and professions cooperating with them during the provision of services in the field of bariatric and metabolic surgery, as well as the entire care process before and after surgery. The following standards constitute the minimum requirements set by the SCMiB TCHP for good practice of the basic process of bariatric care throughout its entire period, which ensure satisfactory safety and effectiveness of the obesity treatment and its metabolic complications.
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