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1

A multifaceted analysis of the relationship between daily temperature of river water and air

Graf Renata

Acta Geophysica

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2019

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Vol. 67, no. 3

905--920

EN

The aim of the study was to establish the strength and direction of the relationship between daily temperature of river water and air with the use of selected estimation methods. The relationship was assessed for the River Noteć and its tributaries (Western Poland), using the cross-correlation function and Granger causality. The study established cause-and-effect relations for “water–air” and “air–water” directions of influence. It was confirmed that forecasting the pattern of flowing water temperature from changes in air temperature yields better results when done based on data from the previous day. Results of modelling the relationship between data series with the use of the linear and natural cubic splines models confirmed the presence of a nonlinear relation. It was also established that there is a statistically significant correlation of random fluctuations for both temperature series on the same days. This made it possible to confirm the occurrence of short-term connections between water and air temperature. The results can be used to determine the qualities of thermal regimes and to predict temperature of river waters in the conditions of climate change.

2

Carbon emissions, energy use, gross domestic product and total population in China

Ahmad M., Hengyi H., Rahman Z. U., Khan Z. U., Khan S., Khan Z.

Ekonomia i Środowisko

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2018

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nr 2

32--44

EN

The current study explores the impact of energy consumption, total population, gross domestic product on carbon emissions by utilizing time series data of 1971-2013 for China. Earlier studies concentrated on testing the present form of an environmental Kuznets curve not taking total population in a model. Specifically, this study focuses on analyzing the long run existence of environmental Kuznets curve. The methodology of auto regressive distributed lag model is utilized. The quadratic linkage between national income and emissions of carbon have been detected, confirming the presence of long run linkage between quadratic national income and emissions of carbon. Granger causality test divulge one-way causality between gross domestic product and carbon emissions. The empirical findings also reveal that the energy use and national income are important factors of carbon emanations in the long run. Total population has an insignificant positive influence on emissions of carbon. It is suggested that government should focus to extract that substitute sources of energy which is more environmental friendly.

3

The analysis of relations between primary fuel prices on the european market in the period 2001-2011

Papież M., Śmiech S.

Rynek Energii

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2011

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Nr 5

139-144

EN

Safety and development of a country depends on its capability to provide the energy it needs. So far the majority of energy has been obtained from non-renewable sources, i.e. crude oil, natural gas and steam coal. The aim of the article is to present the relations between the prices of the most important primary fuels on the European market in the period between October 2001 and May 2011. Causality between the prices will also be investigated. The identification of the mechanisms influencing prices on the raw material market will be conducted using the method of multiple time series analysis. The results of the analysis reveal that in this period the prices of crude oil, natural gas and steam coal were in a long-run equilibrium. Market mechanisms make the prices increase together and decrease together in the long-run, which, one may be tempted to explain by fundamental factors (especially changing economic conjuncture) and weather (bitterly cold winter), both causing substantial changes in the demand for energy sources. However, it is contradicted by the analysis of Granger causality, which shows that the variables of the system should not be treated in the same way.

PL

Celem referatu jest przedstawienie wzajemnych relacji pomiędzy cenami najważniejszych paliw pierwotnych (ropy, gazu ziemnego i węgla energetycznego) na rynku europejskim w okresie październik 2001- maj 2011. Warte odpowiedzi są pytania o przyczynowość występującą pomiędzy cenami. Identyfikacja mechanizmów oddziaływania cen na rynku surowców została prowadzona z wykorzystaniem metod analizy wielowymiarowych szeregów czasowych. Wyniki analizy pokazały, że analizowane ceny znajdowały się w długookresowej równowadze, a więc w długim okresie ceny wspólnie rosną i wspólnie spadają. Można by przypuszczać, że jest to spowodowane czynnikami fundamentalnymi (koniunkturą gospodarczą) i pogodowymi, które powodują zmiany popytu nośników energii. Niemniej przeprowadzona analiza przyczynowości w sensie Grangera pokazuje, że nie można wszystkich zmiennych systemu traktować tak samo. Główną inspiracją zmian cen nośników energii nieodnawialnej okazały się ceny ropy naftowej. Przeszłe ceny ropy pomagają prognozować pozostałe ceny surowców i mogą być traktowane jako przyczyny tych zmian. Z kolei przeszłe ceny gazu ziemnego (węgla energetycznego) nie mają znaczenia dla prognozowania cen ropy i węgla (gazu).