Testing approaches to simulate drainage from the canopy in interception models

2020 ◽  
Author(s):  
Sandra Grunicke ◽  
Max Plorin ◽  
Christian Bernhofer ◽  
Ronald Queck
Keyword(s):  
Model Description ◽  
R Language ◽  
Spatially Resolved ◽  
German Science ◽  
Annual Time Series ◽  
Rain Events ◽  
Precise Simulation ◽  
Annual Time ◽  
German Science Foundation

<p>Drainage from the canopy is one of the sub-processes described in conceptual interception models. In theory, this refers to rainfall water that is temporally stored on the canopy and starts to drip down, when the canopy is saturated. In most Rutter-type models, storage in the canopy is described as a single linear storage (in multilayer models as a storage cascade) from which the drainage occurs after a saturation value is reached. For a precise simulation of the timing and amount of canopy drainage, this approach appears to be insufficient. E.g., with large time-steps and highly filled storage, drainage rates can become larger than the precipitation intensity, leading to a negative storage.</p><p>In our study, we present a review of different approaches to simulate drainage according to literature. We test those approaches using the interception model <em>CanWat</em>, which allows temporally and spatially resolved simulations of the relevant processes. <em>CanWat</em> relies on a vegetation model derived from terrestrial laser scans for a detailed description of the stand. <em>CanWat</em> is written in R language allowing to process multi-annual time series for a study area up to 1 km² with a spatial resolution of 1 m<sup>3</sup> on a PC. For validation purposes, we use rain events that are available from long-term continuous measurements of interception in a spruce stand (mainly <em>Picea abies</em>; a continuous flux site since started within EUROFLUX in 1996) within the Tharandter Wald Southwest of Dresden.</p><p>We outline benefits and limitations of each approach and evaluate which one best fits the needs for a precise simulation of the timing and amount of canopy drainage. The implementation and refinement of the most suitable drainage simulation approach into CanWat is part of the overall attempt to improve the model description of the interception process being the focus of a German Science Foundation (DFG BE-1721/23-1) interception project.</p>

scholarly journals Prospects of the Nigeria Brewery Industry

2019 ◽  
Vol 2 (1) ◽  
pp. 17-24
Author(s):  
Paul A. Ugboya ◽  
Martins A. Odiamenhi
Keyword(s):  
Time Series Data ◽  
Least Square ◽  
Regression Coefficients ◽  
Series Data ◽  
Ordinary Least Square ◽  
Factors Influencing ◽  
The Future ◽  
Annual Time Series ◽  
Annual Time

This study analyses the economics and determinants of a brewery industry (Guinness Nigeria Limited) with a view of establishing the future of breweries in Nigeria. The specific objectives were to estimate the factors influencing products production and determine the viability of products manufactured by the company. Multiple regression and the ordinary least square techniques were used to analyse the long-term (2006 - 2015) annual time series data observed for the study. The results showed that the major determinant of Stout, Harp and Malt production is demanded. As a significant input, it positively influences product production. The observed values of regression coefficients (R2) are 0.99349 (for Stout), 0.90981 (for Harp), and 0.99498 (for Malt), which indicates that they are reliable for determining the future of Guinness Nigeria Ltd. The results also showed that logarithm of demand for Stout production (LstoutD) of 13.5277, LharpD of 21.8439 and LmaltD of 12.2653 were projected respectively up to the year 2025, an indication that brewery production in the state is viable and that future is bright.

scholarly journals Causal Nexus between Billing Efficiency and Economic Growth in India: An Analysis Using Vector Autoregression

2017 ◽  
Vol 9 (3) ◽  
pp. 184
Author(s):  
Asit Ranjan Mohanty ◽  
Devtosh Chaturvedi ◽  
Suresh Kumar Patra
Keyword(s):  
Economic Growth ◽  
Granger Causality ◽  
Time Series Data ◽  
Vector Autoregression ◽  
Series Data ◽  
Long Run ◽  
Annual Time Series ◽  
Causal Nexus ◽  
Annual Time

Energy being a major factor of production plays a pivotal role in inducing a sustained and high economic growth of an economy. This paper attempts to examine the Vector Autoregression (VAR) based Granger causality between billing efficiency and growth rate of per capita Gross Domestic Product (GDP) of India using annual time series data for the period 1970-71 to 2014-15. The conventional Augmented Dicky-Fuller and Phillips-Perron tests reveal that both the series are non-stationary and individually integrated of order one. Johansen-Juselius cointegration approach finds no evidence on the long-run equilibrium association between these variables. However, the VAR - based Granger causality approach reveals unidirectional causality running from billing efficiency to economic growth without any feedback effect. As regards policy implication, implementation of both the short term and long term measures in improving billing efficiency, through the enhancement of commercial and operational efficiency in electricity distribution sector will undoubtedly aid in achieving sustained and high economic growth in India.

scholarly journals Impact of unemployment by sex and marriage rate on fertility decline: Estimates for Turkey and Greece using CCR model

2021 ◽  
Vol 5 (3) ◽  
pp. 76-89
Author(s):  
Goran Miladinov
Keyword(s):  
Fertility Decline ◽  
Time Series Data ◽  
Marriage Rate ◽  
Fertility Rate ◽  
Series Data ◽  
Annual Time Series ◽  
Canonical Cointegrating Regression ◽  
Annual Time ◽  
Ccr Model

The article analyses the effect of unemployment by sex and marriage rate on fertility changes in Greece and Turkey. The empirical part of the study is based on annual time series data retrieved from the World Bank and National Statistical Offices of Turkey and Greece for 1991–2019. Canonical Cointegrating Regression model is applied for the two countries separately, allowing to quantify the effects of the determinants (crude marriage rate and unemployment rate by sex) on the variation of fertility rate. CCR models show these determinants to be the most significant factors of fertility dynamics in both countries. The results from Engle-Granger and the Phillips-Ouliaris tau (t-statistics) tests confirm the cointegration, i.e., long-term relationship between the variables only for Turkey’s CCR model. However, it was found that in Greece, female unemployment impacts fertility rate negatively and male unemployment has a positive effect on fertility rate; for Turkey modelling shows the opposite relationship. The results of the study suggest that economic uncertainties might be one of the factors contributing to fertility decline in these countries, long-term or in the coming years.

Stochastic Models for Actuarial Use: The Equilibrium Modelling of Local Markets

2009 ◽  
Vol 39 (1) ◽  
pp. 339-370 ◽  
Author(s):  
Robert J. Thomson ◽  
Dmitri V. Gott
Keyword(s):  
Local Market ◽  
Market Participants ◽  
Market Portfolio ◽  
One Year ◽  
The One ◽  
Mean Variance ◽  
Annual Time ◽  
Time Subject

AbstractIn this paper, a long-term equilibrium model of a local market is developed. Subject to minor qualifications, the model is arbitrage-free. The variables modelled are the prices of risk-free zero-coupon bonds – both index-linked and conventional – and of equities, as well as the inflation rate. The model is developed in discrete (nominally annual) time, but allowance is made for processes in continuous time subject to continuous rebalancing. It is based on a model of the market portfolio comprising all the above-mentioned asset categories. The risk-free asset is taken to be the one-year index-linked bond. It is assumed that, conditionally upon information at the beginning of a year, market participants have homogeneous expectations with regard to the forthcoming year and make their decisions in mean-variance space. For the purposes of illustration, a descriptive version of the model is developed with reference to UK data. The parameters produced by that process may be used to inform the determination of those required for the use of the model as a predictive model. Illustrative results of simulations of the model are given.

scholarly journals The impact of forest regeneration on streamflow in 12 mesoscale humid tropical catchments

2013 ◽  
Vol 17 (7) ◽  
pp. 2613-2635 ◽  
Author(s):  
H. E. Beck ◽  
L. A. Bruijnzeel ◽  
A. I. J. M. van Dijk ◽  
T. R. McVicar ◽  
F. N. Scatena ◽  
...  
Keyword(s):  
Time Series ◽  
Land Cover ◽  
Forest Regeneration ◽  
Forest Cover ◽  
Impact Analysis ◽  
Forest Area ◽  
Macro Scale ◽  
Annual Time Series ◽  
The Impact ◽  
Annual Time

Abstract. Although regenerating forests make up an increasingly large portion of humid tropical landscapes, little is known of their water use and effects on streamflow (Q). Since the 1950s the island of Puerto Rico has experienced widespread abandonment of pastures and agricultural lands, followed by forest regeneration. This paper examines the possible impacts of these secondary forests on several Q characteristics for 12 mesoscale catchments (23–346 km2; mean precipitation 1720–3422 mm yr−1) with long (33–51 yr) and simultaneous records for Q, precipitation (P), potential evaporation (PET), and land cover. A simple spatially-lumped, conceptual rainfall–runoff model that uses daily P and PET time series as inputs (HBV-light) was used to simulate Q for each catchment. Annual time series of observed and simulated values of four Q characteristics were calculated. A least-squares trend was fitted through annual time series of the residual difference between observed and simulated time series of each Q characteristic. From this the total cumulative change (Â) was calculated, representing the change in each Q characteristic after controlling for climate variability and water storage carry-over effects between years. Negative values of  were found for most catchments and Q characteristics, suggesting enhanced actual evaporation overall following forest regeneration. However, correlations between changes in urban or forest area and values of  were insignificant (p ≥ 0.389) for all Q characteristics. This suggests there is no convincing evidence that changes in the chosen Q characteristics in these Puerto Rican catchments can be ascribed to changes in urban or forest area. The present results are in line with previous studies of meso- and macro-scale (sub-)tropical catchments, which generally found no significant change in Q that can be attributed to changes in forest cover. Possible explanations for the lack of a clear signal may include errors in the land cover, climate, Q, and/or catchment boundary data; changes in forest area occurring mainly in the less rainy lowlands; and heterogeneity in catchment response. Different results were obtained for different catchments, and using a smaller subset of catchments could have led to very different conclusions. This highlights the importance of including multiple catchments in land-cover impact analysis at the mesoscale.

scholarly journals Trend analysis of water quality parameters for the Nisava river

2013 ◽  
Vol 11 (3) ◽  
pp. 199-210 ◽  
Author(s):  
Milan Gocic ◽  
Slavisa Trajkovic
Keyword(s):  
Water Quality ◽  
Trend Analysis ◽  
Kendall Test ◽  
Quality Parameters ◽  
Water Quality Parameters ◽  
Total Hardness ◽  
Significance Level ◽  
Annual Series ◽  
Annual Time Series ◽  
Annual Time

The data of 12 water quality parameters have been daily monitored at the Nis station on the Nisava River during 2000-2004. The trend analysis was performed on monthly, seasonal and annual time series using the Mann-Kendall test, the Spearman?s Rho test and the linear regression at the 5% significance level. The monthly results showed that significant trends were found only in pH, total hardness, Ca and SO4 data. The results in seasonal series indicated that the significant trends were detected in pH, total hardness, Cl, Ca and SO4 data. In annual series, the trends were insignificant at the 5% significance level.

scholarly journals Investment decisions within the context of financialization: Cointegration evidence from the UK economy

2016 ◽  
Vol 63 (1) ◽  
pp. 113-133 ◽  
Author(s):  
Constantinos Alexiou ◽  
Joseph Nellis
Keyword(s):  
Capital Accumulation ◽  
Investment Decisions ◽  
Causality Tests ◽  
Policy Objectives ◽  
Annual Time Series ◽  
Granger Causality Tests ◽  
Bounds Test ◽  
The Uk ◽  
Annual Time ◽  
Instrumental Role

Within the context of financialization, this empirical study sheds some light on the distributional aspects of the existing intra-capitalist conflict between financial and industrial capital and its concomitant impact, via investment, on the macroeconomy. In doing so, bounds-test cointegration techniques in conjunction with Granger causality tests provide the econometric framework upon which the respective models are tested. Annual time series were used spanning from 1971 to 2012, for the UK. The empirical evidence is in line with the theoretical exposition insofar as investment decisions by industry are significantly conditioned by industrial profit. Moreover, the distribution of profits between industry and finance, in conjunction with policy objectives, appears to be playing an instrumental role in affecting capital accumulation.

Sign in / Sign up

Export Citation Format

Share Document