DIE ERDE – Journal of the Geographical Society of Berlin
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Mitigation of urban heat stress – a modelling case study for the area of Stuttgart
Get PDFIn 2050 the fraction of urban global population will increase to over 69 %, which means that around 6.3 billion people are expected to live in urban areas (UN 2011). Cities are the predominant habitation places for humans to live and are vulnerable to extreme weather events aggravating phenomena like heat stress. Finding mitigation strategies to sustain future development is of great importance, given expected influences on human health. In this study, the mesoscale numerical model WRF is used on a regional scale for the urban area of Stuttgart, to simulate the effect of urban planning strategies on dynamical processes affecting urban climate. After comparing two urban parameterisation schemes, a sensitivity study for different scenarios is performed; it shows that a change of the reflective properties of surfaces has the highest impact on near-surface temperatures compared to an increase of urban green areas or a decrease of building density. The Urban Heat Island (UHI) describes the temperature difference between urban and rural temperatures; it characterises regional urban climate and is responsible for urban-rural circulation patterns. Applying urban planning measures may decrease the intensity of the UHI in the study area by up to 2 °C by using heat-reflective roof paints or by 1 °C through replacing impervious surfaces by natural vegetation in the urban vicinity – compared to a value of 2.5 °C for the base case. Because of its topographical location in a valley and the overall high temperatures in this region, the area of Stuttgart suffers from heat stress to a comparatively large extent
Export horticulture – empowering female small-scale farmers in Kenya?
Get PDFExport horticulture is one of Kenya’s most dynamic sectors, with the Mount Kenya Region playing a crucial role as a result of its professional large- and small-scale production and marketing structures. The sector is consequently referred to as a “success story of African regional development” (Dolan and Sutherland 2002: 1). A qualitative case study was carried out to understand the impacts on gender inequality of the integration of horticultural smallholdings into the fresh fruit and vegetable (FFV) supply chain to the European market. It will be outlined how export horticulture affects female small-scale farmers with reference to local distribution channels, the organisation of the farm as a group or an individual player, and the specific organisation of labour on the farm. The focus here is on the traditional division of labour, ownership and mobility patterns, as well as on knowledge and income. The study shows that the influence of the integration in the FFV chain on gender inequality is conditioned by both the type of relations to the buyers and the internal and institutional organisation of the smallholding. Surprisingly, in some areas of the primarily male-dominated rural society, an integration in the form of outgrower schemes that resembles Gereffi et al.’s model of a captive value chain, with women farmers exclusively responsible for export production, can enhance gender equality, as women gradually gain more decision-making power and greater independence
Editorial: Dynamics in agricultural value chains
Get PDFThis editorial gives a brief overview on current approaches on value chains and production networks in general and, more specifically, in the field of agriculture. Based on this background it is outlined where the authors see new conceptual and applied perspectives for research in these areas. The individual articles of the special issue are introduced and it is discussed in how far the papers of this special issue can contribute to the aforementioned new research perspectives
On the origin and meaning of the German word Luft and some meteorological terms concerning atmospheric water, especially fog
Get PDFThe English and French word “air” is derived from the Latin aer, which comes from the Greek άήρ. In contrast, the German word “Luft” is a common Proto-Germanic word; in Old English “ lift” and “ lyft”. The word Luft (also Danish, Swedish and Norwegian) is associated with brightness; the German Licht (light), an air (in an atmospheric sense) without fog or clouds. Air and water were originally “elements” in ancient Greek and were transmutable; they represented two kinds of the “ layer of mist” (atmosphere). Dark or thick air was mist or cloud, hiding the gods (who lived in the upper air or sky; the aether). Different terms are presented that describe fog and clouds in connection with the history of the process of understanding. Finally, the word Luft (air) as a term for gaseous chemical compounds (“ kinds of gases”) is discussed. In addition to the German, all terms are given in Greek, Latin, English and French
Indoor heat stress: An assessment of human bioclimate using the UTCI in different buildings in Berlin
Get PDFBecause humans spend most of their time indoors and can be negatively affected by unfavourable thermal environments, the assessment of indoor heat stress is an important issue for public health care. To characterise indoor human bioclimate, the Universal Thermal Climate Index (UTCI) was used. UTCI values were calculated from measurements of air temperature and air humidity in 16 rooms in Berlin during the summer months of 2011 and 2012. A constant air velocity of approximately 0.3 m/s and a metabolic heat production of 135 W/m2 were assumed. The mean radiant temperature was set to the air temperature. Because the mean air humidity was below or slightly above 50 %, the calculated UTCI values were mostly lower than the air temperatures. In summer 2012, the mean UTCI values ranged from 22.2 °C to 27.1 °C, and the maximum UTCI values ranged from 24.7 °C to 35.6 °C. Whereas only minor differences were found between rooms located within comparable buildings in different districts of Berlin, pronounced variations of the UTCI values were detected in two adjoining buildings, with differences up to 8.6 K for the daily minimum, 9.8 K for the daily mean and 12.2 K for the daily maximum UTCI between different rooms. These variations can be explained by differences in the structures of the two buildings, floor level and aspect. The UTCI values were also used to determine the occurrence of moderate and strong heat stress. Only two rooms showed no thermal stress, while strong heat stress was detected in three rooms
Measures against heat stress in the city of Gelsenkirchen, Germany
Get PDFIn the near-surface atmosphere, heat waves during the summer cause situations that may lead to human-biometeo-rological impairment. Because of their high population density, overheated cities are particularly strongly affected by heat stress. In the future, due to the effects of climate change, heat stress will increase in terms of its intensity and spatial expansion in the areas of concern. Taking the example of the city of Gelsenkirchen, Germany, this article presents a method for the identification of areas requiring adaptation or protection. A scenario of the future increase of heat stress events is presented, based on data of the German climate change model STAR II. For the identification of areas requiring adaptation and protection, spatial analyses of the urban heat island, land use and demographic aspects were performed using GIS tools. The application and assessment of adaptation measures is investigated for an urban quarter using the microscale numerical model ENVI-met. Finally adaptation measures in urban planning against heat stress are discussed. The relevant urban planning adaptation measures, which are also important in view of climate change, not only involve heat stress reduction in the residential areas already affected, but also in-volve the protection and optimisation of existing favourable and compensation areas
The distribution systems for organic farming produce in Poland and Spain – similarities and differences
Get PDFAt the turn of the 21st century, European countries experienced a dynamic growth of interest in organic farming and the development of distribution systems for organic farming produce. This article is an attempt to assess the development of the distribution systems for organic farming produce in Spain and Poland and to identify the key drivers determining the systems. A hypothesis has been adopted that, despite different conditions, the systems operate in a similar way in both countries (though various distribution channels have different significance), and that they are becoming more and more similar to the distribution systems for conventional farming produce. New trends in the development of Polish and Spanish distribution channels for organic farming produce have also been identified
Quantification of heat-stress related mortality hazard, vulnerability and risk in Berlin, Germany
Get PDFMany studies have addressed the challenge of heat stress for human health in recent years. However, appropriate concepts and methods for quantifying heat-stress hazards, vulnerabilities and risks are yet under development. The objective of this study is to test the applicability of a risk concept and associated event-based risk-analysis method for quantifying heat-stress related mortality. The study reveals that about 5 % of all deaths between 2001 and 2010 in Berlin can statistically be related to elevated air temperatures. Most of the affected people are 65 years or older, while the mortality of people below 65 years shows only weak statistical correlation to air temperature. Mean daily air temperature was best suitable for risk analysis. The results demonstrate that the novel approach for quantitative risk analysis delivers statistically highly significant results on the city scale when analysing heat stress on an event basis. Performing the risk analysis on a spatially distributed data basis for city districts would allow to account for spatial variations of urban climates and demographic properties. Using indoor climate data is expected to provide new insight into heat-stress related mortality risks, particularly for highly vulnerable persons like elderly persons or patients residing in hospitals
Assessment of urban thermal stress by UTCI – experimental and modelling studies: an example from Poland
Get PDFThe paper presents a new approach to the study of the spatial variability of heat stress in urban areas. The Universal Thermal Climate Index UTCI was applied for this purpose. The spatial variability of UTCI at the local scale was studied using examples of urban areas with different sizes and geographical locations. The experimental research on urban heat stress was conducted in Warsaw. The research covers both differences between UTCI in urban to rural areas as well as the variation of heat stress within small residential districts in Warsaw. We found a very large and significant heat stress gradient between downtown Warsaw and rural stations. Spatial variability of UTCI was also observed in microclimate research. A modelling approach was presented based on examples from Warsaw, a city with a population of almost 2 million, as well as examples from several spa towns with populations of up to 40,000 located in various parts of Poland. GIS analysis (ArcGIS for Desktop and IDRISI) was applied for this purpose
Extreme summer heat in Phoenix, Arizona (USA) under global climate change (2041-2070)
Get PDFSummer extreme heat events in the arid Phoenix, Arizona (USA) metropolitan region for the period 2041-2070 are projected based on the ensemble of ten climate models from the North American Regional Climate Change Assessment Program for the SRES A2 greenhouse gas emissions scenario by the Intergovernmental Panel on Climate Change. Extreme heat events are identified by measures related to two thresholds of the maximum daily air temperature distribution for the historical reference period 1971-2000. Comparing this reference period to the model ensemble-mean, the frequency of extreme heat events is projected to increase by a factor of six to 1.9 events per summer and the average number of event days per year is projected to increase by a factor of 14. The inter-model range for the average number of EHE days per summer is larger for the projected climate, 10.6 to 42.2 days, than for simulations of the past climate simulations (1.5 to 2.4 days)