Samenvatting De Islam kent een verbod op riba, dat gewoonlijk gelijkgesteld wordt aan een verbod ... more Samenvatting De Islam kent een verbod op riba, dat gewoonlijk gelijkgesteld wordt aan een verbod op rente. Het Christendom heeft ook een renteverbod gekend, maar daar functioneert het niet meer. In het Jodendom geldt eveneens een renteverbod. Met de hetter iskah is daar een oplossing gevonden die het renteverbod formeel respecteert terwijl er toch een vooraf overeengekomen vaste vergoeding voor krediet wordt betaald. In het islamitische financieren zijn soortgelijke constructies in gebruik. Een aantal daarvan wordt beschreven. De conclusie is dat het niet goed lukt om renteloos te financieren.
Two objections expressed by Kandler (1992) to our results in a recent article (Visser and Molenaa... more Two objections expressed by Kandler (1992) to our results in a recent article (Visser and Molenaar 1992) are discussed. We argue that, although we did not use all data available from the fi stands under consideration, inclusion of the other measurements would not have changed our conclusions. We also point out that, contrary to Kandler's remark, deposition of pollutants (wet rather than dry deposition) may not be ignored as a potential stress factor in the Bavarian Forest. FOR. ScI. 38(4):870-872 ADDrrIONAL KEY WOP. DS. Tree-ring analysis, chronology building, fir decline. IN A RECENT ARTICLE (Visser and Molemar 1992) we introduced a new methodology for analyzing tree-ring data in relation to environmental conditions. As an application we used ring-width data from four stands of silver fir (Abies alba Mill.) in the Bavarian Forest, Germany. From our analyses we concluded that it is rather unlikely that the drastic drop in wood production since the 1960s and the subsequent recovery in the 1980s can be explained on the basis of meteorological data alone. However, using total annual SO2 emissions in the former FRG as a pollution indicator we found statistically relevant correlations with fir growth and we concluded that pollution is a serious candidate for explaining the anomalous growth behaviour of silver fir. Kandler (1992) questions our conclusions on the basis of two arguments. First, he mentions that the trees in our analysis originate f • om a much wider set of cores. A number of these firs do not show anomalous growth behavior. Second, he doubts the relevance of the SO2 data we used. In the following sections we will reply to both arguments. TREE-RING DATA We acknowledge the remarks made by Kandler concerning the existence of a much wider set of cores at the locations Zwiesel and Neureichenau. His Figure i also shows fir chronologies with less pronounced growth anomalies since the 1960s. We were unaware of the existence of these data. It should be mentioned, however, that not only Eckstein and Sass (1989) but also Kandler (1988) himself make inferences on the subject of fir decline using the same data as we did, without mentioning the wider set of cores. In fact, we used the data given in Figure 13 of Kandler (1988). If we had used the wider set of data, this would hardly have influenced our findings. Averaging of all the data in Figure i of Kandler (1992) still leads to an overall tree-ring chronology with a distinct dip during the period 1970-1985:212 out of 251 cores (84%) show this phenomenon of "Tannensterben." Furthermore, we recall that the pattern of decline and recovery of firs has been observed by many researchers. Thus, the pattern is not an artifact of the stands at Zwiesel and Neureichenau. References are given in our article. AIR POLLUTION We do not agree with Kandler's remarks on the level of air pollution in the Bavarian forest. Indeed, the concentrations of SO • are relatively low in Bavaria (Figures 2 and 3 in his comment). However, the deposition of S-compounds is high in this area, which is illustrated by Figure 1. This figure shows that deposition of SOx in Bavarian lies between 800 and 1600 (mol ha-• yr-•). Deposition levels in the Ruhr area are not different. This counterintuitive result is explained by the fact that deposition in the Ruhr area consists for-67% of dry deposition and for-33% of wet deposition. Therefore, local pollution sources will contribute significantly to deposition levels in this area. The situation in Bavaria, with its high level of precipitation (-1250 mm/yr), is quite 870/FORESTSC •-NCE
In dit rapport behandelen we methoden voor gevoeligheids-en onzekerheidsanalyses voor rekenintens... more In dit rapport behandelen we methoden voor gevoeligheids-en onzekerheidsanalyses voor rekenintensieve simulatiemodellen. We geven een overzicht van de meest gebruikte methoden en technieken en recente ontwikkelingen op het gebied van gevoeligheids-en onzekerheidsanalyse, waarbij we de nadruk leggen op beperking van de benodigde rekentijd. Technieken voor lokale en globale gevoeligheidsanalyse komen aan bod, met speciale aandacht voor metamodellering, factorial designs en de adjoint vergelijking methode.
Een toepassing van Structurele Tijdreeksmodellen en het Kalmanfilter H. Visser Dit onderzoek werd... more Een toepassing van Structurele Tijdreeksmodellen en het Kalmanfilter H. Visser Dit onderzoek werd verricht in opdracht en ten laste van MAP-SOR, in het kader van project S/550002/01/TO, Tools ten behoeve van Onzekerheidsanalyse. RIVM, Postbus 1, 3720 BA Bilthoven, telefoon: 030 -274 91 11; fax: 030 -274 29 71 pag. 2 van 97 RIVM rapport 550002002
Comparing maps is an important issue in environmental research. Reasons for comparing maps may be... more Comparing maps is an important issue in environmental research. Reasons for comparing maps may be: (i) the different socio-economic scenarios on which they are based, (ii) detection of temporal changes, (iii) calibration/validation of land-use models, (iv) hotspot detection, (v) their use in uncertainty analysis, and (vi) their origin in different methodologies/models. This report addresses the problem of quantifying subsequent map similarities and dissimilarities.
key words: APA index. climate change. CO. meteorology. time series analsis Absfract: Generally. s... more key words: APA index. climate change. CO. meteorology. time series analsis Absfract: Generally. spatial and temporal fluctuations in concentrations of methane are poorlv understood. For this reason, a project has been started with the title: "Socirces. regional scaling and validation of CH4 and N20 emissions from the ctherlands and Northwest Europe. As part of this project ve deal here with the delection of local emission sources fron7 temporal concentration patterns in The Netherlands. 139 J. van Ham et aL (eds.),
An analysis of historical and future trends in weather conditions, weather extremes and temperatu... more An analysis of historical and future trends in weather conditions, weather extremes and temperature-related impacts
Are there significant trends in temperatures and precipitation over the past hundred years? And d... more Are there significant trends in temperatures and precipitation over the past hundred years? And do these series show some cyclic behaviour corresponding to sun spot numbers? Or, can we detect significant downward trends in concentrations of Particulate Matter? And what is the role of meteorological conditions? Are observed trends due to reduced emissions?
It is well-known that a large part of the year-to-year variation in annual distribution of daily ... more It is well-known that a large part of the year-to-year variation in annual distribution of daily concentrations of air pollutants is due to fluctuations in the frequency and severity of meteorological conditions. This variability makes it difficult to estimate the effectiveness of emission control strategies.
Samenvatting De Islam kent een verbod op riba, dat gewoonlijk gelijkgesteld wordt aan een verbod ... more Samenvatting De Islam kent een verbod op riba, dat gewoonlijk gelijkgesteld wordt aan een verbod op rente. Het Christendom heeft ook een renteverbod gekend, maar daar functioneert het niet meer. In het Jodendom geldt eveneens een renteverbod. Met de hetter iskah is daar een oplossing gevonden die het renteverbod formeel respecteert terwijl er toch een vooraf overeengekomen vaste vergoeding voor krediet wordt betaald. In het islamitische financieren zijn soortgelijke constructies in gebruik. Een aantal daarvan wordt beschreven. De conclusie is dat het niet goed lukt om renteloos te financieren.
Two objections expressed by Kandler (1992) to our results in a recent article (Visser and Molenaa... more Two objections expressed by Kandler (1992) to our results in a recent article (Visser and Molenaar 1992) are discussed. We argue that, although we did not use all data available from the fi stands under consideration, inclusion of the other measurements would not have changed our conclusions. We also point out that, contrary to Kandler's remark, deposition of pollutants (wet rather than dry deposition) may not be ignored as a potential stress factor in the Bavarian Forest. FOR. ScI. 38(4):870-872 ADDrrIONAL KEY WOP. DS. Tree-ring analysis, chronology building, fir decline. IN A RECENT ARTICLE (Visser and Molemar 1992) we introduced a new methodology for analyzing tree-ring data in relation to environmental conditions. As an application we used ring-width data from four stands of silver fir (Abies alba Mill.) in the Bavarian Forest, Germany. From our analyses we concluded that it is rather unlikely that the drastic drop in wood production since the 1960s and the subsequent recovery in the 1980s can be explained on the basis of meteorological data alone. However, using total annual SO2 emissions in the former FRG as a pollution indicator we found statistically relevant correlations with fir growth and we concluded that pollution is a serious candidate for explaining the anomalous growth behaviour of silver fir. Kandler (1992) questions our conclusions on the basis of two arguments. First, he mentions that the trees in our analysis originate f • om a much wider set of cores. A number of these firs do not show anomalous growth behavior. Second, he doubts the relevance of the SO2 data we used. In the following sections we will reply to both arguments. TREE-RING DATA We acknowledge the remarks made by Kandler concerning the existence of a much wider set of cores at the locations Zwiesel and Neureichenau. His Figure i also shows fir chronologies with less pronounced growth anomalies since the 1960s. We were unaware of the existence of these data. It should be mentioned, however, that not only Eckstein and Sass (1989) but also Kandler (1988) himself make inferences on the subject of fir decline using the same data as we did, without mentioning the wider set of cores. In fact, we used the data given in Figure 13 of Kandler (1988). If we had used the wider set of data, this would hardly have influenced our findings. Averaging of all the data in Figure i of Kandler (1992) still leads to an overall tree-ring chronology with a distinct dip during the period 1970-1985:212 out of 251 cores (84%) show this phenomenon of "Tannensterben." Furthermore, we recall that the pattern of decline and recovery of firs has been observed by many researchers. Thus, the pattern is not an artifact of the stands at Zwiesel and Neureichenau. References are given in our article. AIR POLLUTION We do not agree with Kandler's remarks on the level of air pollution in the Bavarian forest. Indeed, the concentrations of SO • are relatively low in Bavaria (Figures 2 and 3 in his comment). However, the deposition of S-compounds is high in this area, which is illustrated by Figure 1. This figure shows that deposition of SOx in Bavarian lies between 800 and 1600 (mol ha-• yr-•). Deposition levels in the Ruhr area are not different. This counterintuitive result is explained by the fact that deposition in the Ruhr area consists for-67% of dry deposition and for-33% of wet deposition. Therefore, local pollution sources will contribute significantly to deposition levels in this area. The situation in Bavaria, with its high level of precipitation (-1250 mm/yr), is quite 870/FORESTSC •-NCE
In dit rapport behandelen we methoden voor gevoeligheids-en onzekerheidsanalyses voor rekenintens... more In dit rapport behandelen we methoden voor gevoeligheids-en onzekerheidsanalyses voor rekenintensieve simulatiemodellen. We geven een overzicht van de meest gebruikte methoden en technieken en recente ontwikkelingen op het gebied van gevoeligheids-en onzekerheidsanalyse, waarbij we de nadruk leggen op beperking van de benodigde rekentijd. Technieken voor lokale en globale gevoeligheidsanalyse komen aan bod, met speciale aandacht voor metamodellering, factorial designs en de adjoint vergelijking methode.
Een toepassing van Structurele Tijdreeksmodellen en het Kalmanfilter H. Visser Dit onderzoek werd... more Een toepassing van Structurele Tijdreeksmodellen en het Kalmanfilter H. Visser Dit onderzoek werd verricht in opdracht en ten laste van MAP-SOR, in het kader van project S/550002/01/TO, Tools ten behoeve van Onzekerheidsanalyse. RIVM, Postbus 1, 3720 BA Bilthoven, telefoon: 030 -274 91 11; fax: 030 -274 29 71 pag. 2 van 97 RIVM rapport 550002002
Comparing maps is an important issue in environmental research. Reasons for comparing maps may be... more Comparing maps is an important issue in environmental research. Reasons for comparing maps may be: (i) the different socio-economic scenarios on which they are based, (ii) detection of temporal changes, (iii) calibration/validation of land-use models, (iv) hotspot detection, (v) their use in uncertainty analysis, and (vi) their origin in different methodologies/models. This report addresses the problem of quantifying subsequent map similarities and dissimilarities.
key words: APA index. climate change. CO. meteorology. time series analsis Absfract: Generally. s... more key words: APA index. climate change. CO. meteorology. time series analsis Absfract: Generally. spatial and temporal fluctuations in concentrations of methane are poorlv understood. For this reason, a project has been started with the title: "Socirces. regional scaling and validation of CH4 and N20 emissions from the ctherlands and Northwest Europe. As part of this project ve deal here with the delection of local emission sources fron7 temporal concentration patterns in The Netherlands. 139 J. van Ham et aL (eds.),
An analysis of historical and future trends in weather conditions, weather extremes and temperatu... more An analysis of historical and future trends in weather conditions, weather extremes and temperature-related impacts
Are there significant trends in temperatures and precipitation over the past hundred years? And d... more Are there significant trends in temperatures and precipitation over the past hundred years? And do these series show some cyclic behaviour corresponding to sun spot numbers? Or, can we detect significant downward trends in concentrations of Particulate Matter? And what is the role of meteorological conditions? Are observed trends due to reduced emissions?
It is well-known that a large part of the year-to-year variation in annual distribution of daily ... more It is well-known that a large part of the year-to-year variation in annual distribution of daily concentrations of air pollutants is due to fluctuations in the frequency and severity of meteorological conditions. This variability makes it difficult to estimate the effectiveness of emission control strategies.
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