scholarly journals Accounting for the climate–carbon feedback in emission metrics

2017 ◽  
Vol 8 (2) ◽  
pp. 235-253 ◽  
Author(s):  
Thomas Gasser ◽  
Glen P. Peters ◽  
Jan S. Fuglestvedt ◽  
William J. Collins ◽  
Drew T. Shindell ◽  
...  
Keyword(s):  
Global Warming ◽  
Impulse Response ◽  
Response Function ◽  
Impulse Response Function ◽  
The Other ◽  
System Model ◽  
Earth System ◽  
Assessment Report ◽  
Global Temperature Change ◽  
Relative Metric

Abstract. Most emission metrics have previously been inconsistently estimated by including the climate–carbon feedback for the reference gas (i.e. CO2) but not the other species (e.g. CH4). In the fifth assessment report of the IPCC, a first attempt was made to consistently account for the climate–carbon feedback in emission metrics. This attempt was based on only one study, and therefore the IPCC concluded that more research was needed. Here, we carry out this research. First, using the simple Earth system model OSCAR v2.2, we establish a new impulse response function for the climate–carbon feedback. Second, we use this impulse response function to provide new estimates for the two most common metrics: global warming potential (GWP) and global temperature-change potential (GTP). We find that, when the climate–carbon feedback is correctly accounted for, the emission metrics of non-CO2 species increase, but in most cases not as much as initially indicated by IPCC. We also find that, when the feedback is removed for both the reference and studied species, these relative metric values only have modest changes compared to when the feedback is included (absolute metrics change more markedly). Including or excluding the climate–carbon feedback ultimately depends on the user's goal, but consistency should be ensured in either case.

scholarly journals Accounting for the climate-carbon feedback in emission metrics

2016 ◽  
Author(s):  
Thomas Gasser ◽  
Glen P. Peters ◽  
Jan S. Fuglestvedt ◽  
William J. Collins ◽  
Drew T. Shindell ◽  
...  
Keyword(s):  
Impulse Response ◽  
Response Function ◽  
Climate Model ◽  
Impulse Response Function ◽  
Climate Feedbacks ◽  
Assessment Report ◽  
Time Horizons ◽  
Realistic Representation ◽  
Global Temperature Change ◽  
Short Time

Abstract. Most emission metrics have previously been inconsistently estimated by including the climate-carbon feedback for the reference gas (i.e. CO2) but not the other species (e.g. CH4). In the fifth assessment report of the IPCC, a first attempt was made to consistently account for the climate-carbon feedback in emission metrics. This attempt was based on only one study, and therefore the IPCC presented tentative values and concluded that more research was needed. Here, we carry out this research. First, using the simple carbon-climate model OSCAR v2.2, we establish a new impulse response function for the climate-carbon feedback. Second, we use this impulse response function to provide new estimates for the two most usual metrics: Global Warming Potential (GWP) and Global Temperature change Potential (GTP). We find that, when the climate-carbon feedback is correctly accounted for, the emission metrics of non-CO2 species increase, but in most cases not as much as initially indicated by IPCC. We also find that, when the feedback is removed for both the reference and studied species, the metric values only have modest changes, compared to when the feedback is included. However, including carbon-climate feedbacks, particularly in absolute metrics or for short time horizons, gives a more realistic representation of the response.

scholarly journals Intervenções Regulatórias, Volatilidade e Contágio: Uma Análise VIRF

2014 ◽  
Vol 12 (3) ◽  
pp. 385
Author(s):  
Gabriel Godofredo Fiuza de Bragança ◽  
Marcelo De Sales Pessoa ◽  
Katia Rocha
Keyword(s):  
Impulse Response ◽  
Response Function ◽  
Impulse Response Function ◽  
The Other ◽  
Conditional Heteroskedasticity ◽  
Regulatory Interventions ◽  
The One ◽  
The Impact ◽  
Electricity Utilities ◽  
Regulatory Measure

This paper examines how regulatory interventions can affect the market risk of electricity utilities and telecom carriers traded in the Brazilian stock market (BOVESPA). Our article uses a bivariate Generalized AutoRegressive Conditional Heteroskedasticity (GARCH - BEKK) model to analyze the impact of two relevant and surprising measures taken by the correspondent Brazilian regulatory authorities in 2012 (one in each sector) on both markets’ volatilities and covariance. We also adopt the volatility impulse response function (VIRF) developed by Hafner & Herwartz (2006) to estimate their persistence. On the one hand, the results indicate that the effects of the telecommunications’ regulatory intervention are negligible but, on the other hand, the impact of the electricity's regulatory measure is significant, long-lasting and contagious.

Agricultural production in Poland and agri-food exports

2018 ◽  
Vol 63 (4) ◽  
pp. 58-72
Author(s):  
Jacek Strojny
Keyword(s):  
Economic Policy ◽  
Impulse Response ◽  
Response Function ◽  
Agricultural Production ◽  
Vector Autoregression ◽  
Impulse Response Function ◽  
Variance Decomposition ◽  
The Other ◽  
Var Model ◽  
Research Show

The research is aiming at the identification of the dynamic causality between agricultural production in Poland and exports of agri-food goods. Identification of the magnitude and direction of these variables may be used for economic policy forming. The study covers the period of 1991—2013 and is based on the data from the FAO; the research employs the vector autoregression methodology (VAR). The study comprises, among others, the analysis of the impulse response function and variance decomposition of forecasts’ errors of VAR model variables. The results of the research show that agricultural production in Poland is shaped by both own and exports delays. On the other hand, agri-food exports are mainly influenced by their own development trends. This means that, in the VAR model, exports should be seen as a priority ('more exogenous').

Fractional Vector-Order h-Realisation of the Impulse Response Function

2020 ◽  
Vol 14 (2) ◽  
pp. 108-113
Author(s):  
Ewa Pawłuszewicz
Keyword(s):  
Control Systems ◽  
Impulse Response ◽  
Response Function ◽  
Impulse Response Function ◽  
Linear Control ◽  
Linear Control Systems

AbstractThe problem of realisation of linear control systems with the h–difference of Caputo-, Riemann–Liouville- and Grünwald–Letnikov-type fractional vector-order operators is studied. The problem of existing minimal realisation is discussed.

scholarly journals Convolution-based time-domain simulation for fluidelastic instability in tube arrays

2021 ◽  
Author(s):  
Mingjie Zhang ◽  
Ole Øiseth
Keyword(s):  
Impulse Response ◽  
Response Function ◽  
Time Domain ◽  
Impulse Response Function ◽  
Time Domain Simulation ◽  
Unit Step ◽  
Tube Arrays ◽  
Unit Impulse ◽  
The Time Domain ◽  
Unit Impulse Response

AbstractA convolution-based numerical algorithm is presented for the time-domain analysis of fluidelastic instability in tube arrays, emphasizing in detail some key numerical issues involved in the time-domain simulation. The unit-step and unit-impulse response functions, as two elementary building blocks for the time-domain analysis, are interpreted systematically. An amplitude-dependent unit-step or unit-impulse response function is introduced to capture the main features of the nonlinear fluidelastic (FE) forces. Connections of these elementary functions with conventional frequency-domain unsteady FE force coefficients are discussed to facilitate the identification of model parameters. Due to the lack of a reliable method to directly identify the unit-step or unit-impulse response function, the response function is indirectly identified based on the unsteady FE force coefficients. However, the transient feature captured by the indirectly identified response function may not be consistent with the physical fluid-memory effects. A recursive function is derived for FE force simulation to reduce the computational cost of the convolution operation. Numerical examples of two tube arrays, containing both a single flexible tube and multiple flexible tubes, are provided to validate the fidelity of the time-domain simulation. It is proven that the present time-domain simulation can achieve the same level of accuracy as the frequency-domain simulation based on the unsteady FE force coefficients. The convolution-based time-domain simulation can be used to more accurately evaluate the integrity of tube arrays by considering various nonlinear effects and non-uniform flow conditions. However, the indirectly identified unit-step or unit-impulse response function may fail to capture the underlying discontinuity in the stability curve due to the prespecified expression for fluid-memory effects.

scholarly journals Unemployment and COVID-19 Impact in Greece: A Vector Autoregression (VAR) Data Analysis

2021 ◽  
Vol 5 (1) ◽  
pp. 41
Author(s):  
Christos Katris
Keyword(s):  
Data Analysis ◽  
Response Function ◽  
Unemployment Rate ◽  
Vector Autoregression ◽  
Impulse Response Function ◽  
Youth Unemployment ◽  
The Other ◽  
Var Model ◽  
Unemployment Rates ◽  
The Impact

In this paper, the scope is to study whether and how the COVID-19 situation affected the unemployment rate in Greece. To achieve this, a vector autoregression (VAR) model is employed and data analysis is carried out. Another interesting question is whether the situation affected more heavily female and the youth unemployment (under 25 years old) compared to the overall unemployment. To predict the future impact of COVID-19 on these variables, we used the Impulse Response function. Furthermore, there is taking place a comparison of the impact of the pandemic with the other European countries for overall, female, and youth unemployment rates. Finally, the forecasting ability of such a model is compared with ARIMA and ANN univariate models.

IMPROVING EXTRACTION OF IMPULSE RESPONSE FUNCTIONS USING STATIONARY WAVELET SHRINKAGE IN TERAHERTZ REFLECTION IMAGING

2010 ◽  
Vol 09 (04) ◽  
pp. 387-394 ◽  
Author(s):  
YANG CHEN ◽  
YIWEN SUN ◽  
EMMA PICKWELL-MACPHERSON
Keyword(s):  
Experimental Data ◽  
Impulse Response ◽  
Response Function ◽  
Impulse Response Function ◽  
Terahertz Imaging ◽  
Impulse Response Functions ◽  
Response Functions ◽  
Inverse Filtering ◽  
Wavelet Shrinkage ◽  
Gaussian Filtering

In terahertz imaging, deconvolution is often performed to extract the impulse response function of the sample of interest. The inverse filtering process amplifies the noise and in this paper we investigate how we can suppress the noise without over-smoothing and losing useful information. We propose a robust deconvolution process utilizing stationary wavelet shrinkage theory which shows significant improvement over other popular methods such as double Gaussian filtering. We demonstrate the success of our approach on experimental data of water and isopropanol.

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