TY - JOUR A1 - Zhou, Bin A1 - Lauwaet, Dirk A1 - Hooyberghs, Hans A1 - De Ridder, Koen A1 - Kropp, Jürgen A1 - Rybski, Diego T1 - Assessing Seasonality in the Surface Urban Heat Island of London JF - Journal of applied meteorology and climatology N2 - This paper assesses the seasonality of the urban heat island (UHI) effect in the Greater London area (United Kingdom). Combining satellite-based observations and urban boundary layer climate modeling with the UrbClim model, the authors are able to address the seasonality of UHI intensity, on the basis of both land surface temperature (LST) and 2-m air temperature, for four individual times of the day (0130, 1030, 1330, and 2230 local time) and the daily means derived from them. An objective of this paper is to investigate whether the UHI intensities that are based on both quantities exhibit a similar hysteresis-like trajectory that is observed for LST when plotting the UHI intensity against the background temperature. The results show that the UrbClim model can satisfactorily reproduce both the observed urban rural LSTs and 2-m air temperatures as well as their differences and the hysteresis in the surface UHI. The hysteresis-like seasonality is largely absent in both the observed and modeled 2-m air temperatures, however. A sensitivity simulation of the UHI intensity to incoming solar radiation suggests that the hysteresis of the LST can mainly be attributed to the seasonal variation in incoming solar radiation. Y1 - 2016 U6 - https://doi.org/10.1175/JAMC-D-15-0041.1 SN - 1558-8424 SN - 1558-8432 VL - 55 SP - 493 EP - 505 PB - American Meteorological Soc. CY - Boston ER - TY - JOUR A1 - Rybski, Diego A1 - Reusser, Dominik Edwin A1 - Winz, Anna-Lena A1 - Fichtner, Christina A1 - Sterzel, Till A1 - Kropp, Jürgen T1 - Cities as nuclei of sustainability? JF - Environment and Planning B: Urban Analytics and City Science N2 - We have assembled CO2 emission figures from collections of urban GHG emission estimates published in peer-reviewed journals or reports from research institutes and non-governmental organizations. Analyzing the scaling with population size, we find that the exponent is development dependent with a transition from super- to sub-linear scaling. From the climate change mitigation point of view, the results suggest that urbanization is desirable in developed countries. Further, we compare this analysis with a second scaling relation, namely the fundamental allometry between city population and area, and propose that density might be a decisive quantity too. Last, we derive the theoretical country-wide urban emissions by integration and obtain a dependence on the size of the largest city. KW - Scaling KW - cities KW - climate change KW - development process KW - allometry Y1 - 2017 U6 - https://doi.org/10.1177/0265813516638340 SN - 2399-8083 SN - 2399-8091 VL - 44 IS - 3 SP - 425 EP - 440 PB - Sage Publ. CY - London ER - TY - GEN A1 - Prahl, Boris F. A1 - Rybski, Diego A1 - Boettle, Markus A1 - Kropp, Jürgen T1 - Damage functions for climate-related hazards BT - unification and uncertainty analysis T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - Most climate change impacts manifest in the form of natural hazards. Damage assessment typically relies on damage functions that translate the magnitude of extreme events to a quantifiable damage. In practice, the availability of damage functions is limited due to a lack of data sources and a lack of understanding of damage processes. The study of the characteristics of damage functions for different hazards could strengthen the theoretical foundation of damage functions and support their development and validation. Accordingly, we investigate analogies of damage functions for coastal flooding and for wind storms and identify a unified approach. This approach has general applicability for granular portfolios and may also be applied, for example, to heat-related mortality. Moreover, the unification enables the transfer of methodology between hazards and a consistent treatment of uncertainty. This is demonstrated by a sensitivity analysis on the basis of two simple case studies (for coastal flood and storm damage). The analysis reveals the relevance of the various uncertainty sources at varying hazard magnitude and on both the microscale and the macroscale level. Main findings are the dominance of uncertainty from the hazard magnitude and the persistent behaviour of intrinsic uncertainties on both scale levels. Our results shed light on the general role of uncertainties and provide useful insight for the application of the unified approach. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 534 KW - coastal flood damage KW - sea-level rise KW - of-the-art KW - sensitivity-analysis KW - natural hazards KW - storm damage KW - model KW - wind KW - vulnerability KW - buildings Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-410184 SN - 1866-8372 IS - 534 ER - TY - JOUR A1 - Prahl, Boris F. A1 - Rybski, Diego A1 - Boettle, Markus A1 - Kropp, Jürgen T1 - Damage functions for climate-related hazards: unification and uncertainty analysis JF - Natural hazards and earth system sciences N2 - Most climate change impacts manifest in the form of natural hazards. Damage assessment typically relies on damage functions that translate the magnitude of extreme events to a quantifiable damage. In practice, the availability of damage functions is limited due to a lack of data sources and a lack of understanding of damage processes. The study of the characteristics of damage functions for different hazards could strengthen the theoretical foundation of damage functions and support their development and validation. Accordingly, we investigate analogies of damage functions for coastal flooding and for wind storms and identify a unified approach. This approach has general applicability for granular portfolios and may also be applied, for example, to heat-related mortality. Moreover, the unification enables the transfer of methodology between hazards and a consistent treatment of uncertainty. This is demonstrated by a sensitivity analysis on the basis of two simple case studies (for coastal flood and storm damage). The analysis reveals the relevance of the various uncertainty sources at varying hazard magnitude and on both the microscale and the macroscale level. Main findings are the dominance of uncertainty from the hazard magnitude and the persistent behaviour of intrinsic uncertainties on both scale levels. Our results shed light on the general role of uncertainties and provide useful insight for the application of the unified approach. Y1 - 2016 U6 - https://doi.org/10.5194/nhess-16-1189-2016 SN - 1561-8633 VL - 16 SP - 1189 EP - 1203 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Hic, Ceren A1 - Pradhan, Prajal A1 - Rybski, Diego A1 - Kropp, Jürgen T1 - Food Surplus and Its Climate Burdens JF - Geological Society of America bulletin N2 - Avoiding food loss and waste may counteract the increasing food demand and reduce greenhouse gas (GHG) emissions from the agricultural sector. This is crucial because of limited options available to increase food production. In the year 2010, food availability was 20% higher than was required on a global scale. Thus, a more sustainable food production and adjusted consumption would have positive environmental effects. This study provides a systematic approach to estimate consumer level food waste on a country scale and globally, based on food availability and requirements. The food requirement estimation considers demographic development, body weights, and physical activity levels. Surplus between food availability and requirements of a given country is considered as food waste. The global food requirement changed from 2,300 kcal/cap/day to 2,400 kcal/cap/day during the last 50 years, while food surplus grew from 310 kcal/cap/day to 510 kcal/cap/day. Similarly, GHG emissions related to the food surplus increased from 130 Mt CO2eq/yr to 530 Mt CO2eq/yr, an increase of more than 300%. Moreover, the global food surplus may increase up to 850 kcal/cap/day, while the total food requirement will increase only by 2%-20% by 2050. Consequently, GHG emissions associated with the food waste may also increase tremendously to 1.9-2.5 Gt CO2eq/yr. Y1 - 2016 U6 - https://doi.org/10.1021/acs.est.5b05088 SN - 0013-936X SN - 1520-5851 VL - 50 SP - 4269 EP - 4277 PB - American Chemical Society CY - Washington ER - TY - GEN A1 - Boettle, Markus A1 - Rybski, Diego A1 - Kropp, Jürgen T1 - Quantifying the effect of sea level rise and flood defence BT - a point process perspective on coastal flood damage T2 - Postprints der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe N2 - In contrast to recent advances in projecting sea levels, estimations about the economic impact of sea level rise are vague. Nonetheless, they are of great importance for policy making with regard to adaptation and greenhouse-gas mitigation. Since the damage is mainly caused by extreme events, we propose a stochastic framework to estimate the monetary losses from coastal floods in a confined region. For this purpose, we follow a Peak-over-Threshold approach employing a Poisson point process and the Generalised Pareto Distribution. By considering the effect of sea level rise as well as potential adaptation scenarios on the involved parameters, we are able to study the development of the annual damage. An application to the city of Copenhagen shows that a doubling of losses can be expected from a mean sea level increase of only 11 cm. In general, we find that for varying parameters the expected losses can be well approximated by one of three analytical expressions depending on the extreme value parameters. These findings reveal the complex interplay of the involved parameters and allow conclusions of fundamental relevance. For instance, we show that the damage typically increases faster than the sea level rise itself. This in turn can be of great importance for the assessment of sea level rise impacts on the global scale. Our results are accompanied by an assessment of uncertainty, which reflects the stochastic nature of extreme events. While the absolute value of uncertainty about the flood damage increases with rising mean sea levels, we find that it decreases in relation to the expected damage. T3 - Zweitveröffentlichungen der Universität Potsdam : Mathematisch-Naturwissenschaftliche Reihe - 559 KW - climate-change KW - North-Sea KW - extremes KW - costs KW - 21st-Century KW - adaptation KW - statistics KW - impacts KW - trends KW - cities Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:kobv:517-opus4-412405 SN - 1866-8372 IS - 559 ER - TY - JOUR A1 - Boettle, Markus A1 - Rybski, Diego A1 - Kropp, Jürgen T1 - Quantifying the effect of sea level rise and flood defence-a point process perspective on coastal flood damage JF - Natural hazards and earth system sciences N2 - In contrast to recent advances in projecting sea levels, estimations about the economic impact of sea level rise are vague. Nonetheless, they are of great importance for policy making with regard to adaptation and greenhouse-gas mitigation. Since the damage is mainly caused by extreme events, we propose a stochastic framework to estimate the monetary losses from coastal floods in a confined region. For this purpose, we follow a Peak-over-Threshold approach employing a Poisson point process and the Generalised Pareto Distribution. By considering the effect of sea level rise as well as potential adaptation scenarios on the involved parameters, we are able to study the development of the annual damage. An application to the city of Copenhagen shows that a doubling of losses can be expected from a mean sea level increase of only 11 cm. In general, we find that for varying parameters the expected losses can be well approximated by one of three analytical expressions depending on the extreme value parameters. These findings reveal the complex interplay of the involved parameters and allow conclusions of fundamental relevance. For instance, we show that the damage typically increases faster than the sea level rise itself. This in turn can be of great importance for the assessment of sea level rise impacts on the global scale. Our results are accompanied by an assessment of uncertainty, which reflects the stochastic nature of extreme events. While the absolute value of uncertainty about the flood damage increases with rising mean sea levels, we find that it decreases in relation to the expected damage. Y1 - 2016 U6 - https://doi.org/10.5194/nhess-16-559-2016 SN - 1561-8633 VL - 16 SP - 559 EP - 576 PB - Copernicus CY - Göttingen ER - TY - JOUR A1 - Fluschnik, Till A1 - Kriewald, Steffen A1 - Ros, Anselmo Garcia Cantu A1 - Zhou, Bin A1 - Reusser, Dominik Edwin A1 - Kropp, Jürgen A1 - Rybski, Diego T1 - The Size Distribution, Scaling Properties and Spatial Organization of Urban Clusters: A Global and Regional Percolation Perspective JF - ISPRS International Journal of Geo-Information N2 - Human development has far-reaching impacts on the surface of the globe. The transformation of natural land cover occurs in different forms, and urban growth is one of the most eminent transformative processes. We analyze global land cover data and extract cities as defined by maximally connected urban clusters. The analysis of the city size distribution for all cities on the globe confirms Zipf’s law. Moreover, by investigating the percolation properties of the clustering of urban areas we assess the closeness to criticality for various countries. At the critical thresholds, the urban land cover of the countries undergoes a transition from separated clusters to a gigantic component on the country scale. We study the Zipf-exponents as a function of the closeness to percolation and find a systematic dependence, which could be the reason for deviating exponents reported in the literature. Moreover, we investigate the average size of the clusters as a function of the proximity to percolation and find country specific behavior. By relating the standard deviation and the average of cluster sizes—analogous to Taylor’s law—we suggest an alternative way to identify the percolation transition. We calculate spatial correlations of the urban land cover and find long-range correlations. Finally, by relating the areas of cities with population figures we address the global aspect of the allometry of cities, finding an exponent δ ≈ 0.85, i.e., large cities have lower densities. Y1 - 2016 U6 - https://doi.org/10.3390/ijgi5070110 SN - 2220-9964 VL - 5 SP - 1543 EP - 1559 PB - MDPI CY - Basel ER -