•An evaluation of the use of LCZ maps in a local scale urban climate model.•Extensive analysis of temperature regime for each LCZ in our study areas.•Spatially explicit information on hot spots in ...terms of mitigation needs for urban planning.
High population densities in cities and rapid urban growth increase the vulnerability of the urban environment to extreme weather events. Urban planning should account for these extreme events as efficiently as possible. One way is to locate hot spots in an urban environment by mapping cities into local climate zones (LCZ) and evaluate heat stress related to these zones. LCZs are likely to become a standard in urban climate modelling as they capture important urban morphological characteristics. For instance, temperature regimes linked to spatially explicit LCZ maps should be assessed for all LCZ zones derived from these maps. This study assesses the thermal behavior of mapped LCZs using simulated temperature data from the UrbClim model. Prior to temperature analysis, the model was validated with observational data. To evaluate the robustness of the analysis, we ran the model in three cities in Belgium: Antwerp, Brussels, and Ghent. The results show that temperature regimes are significantly different for all the built zones in the urban environment independent of the city. Second, the susceptibility to heat stress can differ greatly depending on the zone. The unique thermal behavior of the different LCZs provides indispensable information on the urban environment and its climatic conditions. This study shows that the LCZ scheme has a potential to help urban planners globally tackle adverse effects of extreme weather events.
The most frequently used climate classification map is that of Wladimir Köppen, presented in its latest version 1961 by Rudolf Geiger. A huge number of climate studies and subsequent publications ...adopted this or a former release of the Köppen-Geiger map. While the climate classification concept has been widely applied to a broad range of topics in climate and climate change research as well as in physical geography, hydrology, agriculture, biology and educational aspects, a well-documented update of the world climate classification map is still missing. Based on recent data sets from the Climatic Research Unit (CRU) of the University of East Anglia and the Global Precipitation Climatology Centre (GPCC) at the German Weather Service, we present here a new digital Köppen-Geiger world map on climate classification, valid for the second half of the 20th century.
Genetic and physiological studies have to-date revealed evidence for five signaling pathways by which the chloroplast exerts retrograde control over nuclear genes. One of these pathways is dependent ...on product(s) of plastid protein synthesis, for another the signal is singlet oxygen, a third employs chloroplast-generated hydrogen peroxide, a fourth is controlled by the redox state of the photosynthetic electron transport chain, and a fifth involves intermediates and possibly proteins of tetrapyrrole biosynthesis. These five pathways may be part of a complex signaling network that links the functional and physiological state of the chloroplast to the nucleus. Mutants defective in various steps of photosynthesis reveal a surprising diversity in nuclear responses suggesting the existence of a complex signaling network.
As climate change progresses, it is causing more frequent and severe heat waves, resulting in higher indoor temperatures. Various temperature thresholds for indicating indoor overheating have been ...proposed in different contexts, extending from reduced comfort in buildings to subjective heat stress and onset of first or serious health problems. This study reviews these thresholds and identifies threshold values for subjective heat stress of occupants in the city of Augsburg, Germany, distinguishing between vulnerable and non-vulnerable households. Survey data from 427 private households are analysed using unpaired analysis of variances (ANOVA), t-tests and regression analysis to identify factors related to subjective heat stress at home during night-time. The findings imply that health implications during heat waves, age, local climate zones favouring the urban heat island effect and higher indoor temperature represent significant factors for subjective heat stress. A significant difference in subjective heat stress among different groups related to temperature could be identified for thresholds of 24.8 °C (people living alone) and 26.7 °C (people with chronic disease). As WHO threshold for health risk from overheating is 24 °C, people are apparently at heat-related risk without feeling that they are at risk, especially when they have chronic diseases; thus they may not see the urgency of taking adaptation measures.
In this contribution air temperature differences among Local Climate Zone (LCZ) categories are analysed with special consideration of varying synoptic conditions. Analyses are based upon an LCZ ...mapping for the urban area of Augsburg (Bavaria, Southern Germany) and hourly air temperature data from a comprehensive logger network. Quality checked air temperature measurements have been stratified according to season, hour of the day and weather situation. For resulting subsamples thermal differences among LCZs have been determined and appropriate statistical tests have been applied. Results confirm that built up LCZs feature higher temperatures than natural LCZs and that most distinct differences among LCZs appear under undisturbed synoptic conditions. With increasing cloudiness and in particular with increasing wind speed differences among LCZs diminish. But, even for strongly disturbed synoptic conditions statistical significance of the influence of LCZs on thermal characteristics could be assured. Thus, our findings provide clear evidence that detectable thermal differences among LCZs are not restricted to „ideal “synoptic conditions but occur as well under disturbed conditions. However, to assure not only the statistical but also the climatological and in particular the bioclimatological and human health related relevance of the documented differences among LCZs further studies incorporating appropriate metrics are intended.
Blue light as an environmental cue plays a pivotal role in controlling the progression of the sexual life cycle in the green alga Chlamydomonas reinhardtii. Phototropin was considered a prime ...candidate for the blue-light receptor involved. By using the RNA interference method, knockdown strains with reduced phototropin levels were isolated. Those with severely reduced levels of this photoreceptor were partially impaired in three steps of the life cycle: in gametogenesis, the maintenance of mating ability, and the germination of zygotes. These observations suggest that phototropin is the principal sensory molecule used by this alga for the control of its life cycle by light.
Abstract
Extreme heatwaves will occur more frequently and with higher intensity in future. Their consequences for human health can be fatal if adaptation measures will not be taken. This study ...analyses factors related to heat adaptation measures in private households in Germany. During the summer months of 2019, indoor temperatures were measured in over 500 private households in the City of Augsburg, Germany, accompanied by a survey to find out about heat perception and adaptation measures. Hypotheses deducted from the Protective Action Decision Model were tested using one-way ANOVAs, regression analysis and in the end a multiple hierarchical regression model. The results of the hypotheses tested imply an influence of knowledge and heat risk perception of heat adaptation behaviour and an influence of age on heat risk perception. The results of the regression model show an influence of the efficacy-related attribute, of age, indoor temperature, subjective heat stress and health implications to heat adaptation behaviour. In the end, this study proposes adjustments to the PADM according to the results of the hierarchical regression analysis.
Summary
Phototropin (PHOT) is a photoreceptor involved in a variety of blue‐light‐elicited physiological processes including phototropism, chloroplast movement and stomatal opening in plants. The ...work presented here tests whether PHOT is involved in expression of light‐regulated genes in Chlamydomonas reinhardtii. When C. reinhardtii was transferred from the dark to very low‐fluence rate white light, there was a substantial increase in the level of transcripts encoding glutamate‐1‐semialdehyde aminotransferase (GSAT), phytoene desaturase (PDS) and light‐harvesting polypeptides (e.g. LHCBM6). Increased levels of these transcripts were also elicited by low‐intensity blue light, and this blue‐light stimulation was suppressed in three different RNAi strains that synthesize low levels of PHOT. The levels of GSAT and LHCBM6 transcripts also increased following exposure of algal cells to low‐intensity red light (RL). The red‐light‐dependent increase in transcript abundance was not affected by the electron transport inhibitor 3‐(3,4‐dichlorophenyl)‐1,1‐dimethylurea, implying that the influence of RL on transcript accumulation was not controlled by cytoplasmic redox conditions, and that a red‐light photoreceptor(s) may be involved in regulating the levels of transcripts from specific photosynthesis‐related genes in C. reinhardtii. Interestingly, elevated GSAT and LHCBM6 transcript levels in RL were significantly reduced in the PHOT RNAi strains, which raises the possibility of co‐action between blue and RL signaling pathways. Microarray experiments indicated that the levels of several transcripts for photosystem (PS) I and II polypeptides were also modulated by PHOT. These data suggest that, in C. reinhardtii, (i) PHOT is involved in blue‐light‐mediated changes in transcript accumulation, (ii) synchronization of the synthesis of chlorophylls (Chl), carotenoids, Chl‐binding proteins and other components of the photosynthetic apparatus is achieved, at least in part, through PHOT‐mediated signaling, and (iii) a red‐light photoreceptor can also influence levels of certain transcripts associated with photosynthetic function, although its action requires normal levels of PHOT.
To gain insight into the chloroplast-to-nucleus signaling role of tetrapyrroles, Chlamydomonas reinhardtii mutants in the Mg-chelatase that catalyzes the insertion of magnesium into protoporphyrin IX ...were isolated and characterized. The four mutants lack chlorophyll and show reduced levels of Mg-tetrapyrroles but increased levels of soluble heme. In the mutants, light induction of HSP70A was preserved, although Mg-protoporphyrin IX has been implicated in this induction. In wild-type cells, a shift from dark to light resulted in a transient reduction in heme levels, while the levels of Mg-protoporphyrin IX, its methyl ester, and protoporphyrin IX increased. Hemin feeding to cultures in the dark activated HSP70A. This induction was mediated by the same plastid response element (PRE) in the HSP70A promoter that has been shown to mediate induction by Mg-protoporphyrin IX and light. Other nuclear genes that harbor a PRE in their promoters also were inducible by hemin feeding. Extended incubation with hemin abrogated the competence to induce HSP70A by light or Mg-protoporphyrin IX, indicating that these signals converge on the same pathway. We propose that Mg-protoporphyrin IX and heme may serve as plastid signals that regulate the expression of nuclear genes.
Ultrafine particles (UFP; diameter less than 100 nm) are ubiquitous in urban air, and an acknowledged risk to human health. At the same time, little is known about the immission situation at typical ...urban sites such as high-traffic roads, residential areas with a high amount of solid fuels for home heating or commercial and industrial areas due to missing legal requirements for measurements of UFP. Therefore, UFP were measured and evaluated in the (sub-)urban background as well as on spots influenced by these various anthropogenic local sources in the city of Augsburg, Germany, for the year 2017. In particular, the spatial and temporal correlations of the UFP concentrations between the seven measurement sites, the quantification and valuation of the contribution of local emitters with regard to their diurnal, weekly and seasonal variations and the influence of meteorological conditions on the formation and dispersion of UFP were investigated. Our analysis results demonstrate that urban UFP concentrations show a pronounced temporal and spatial variability. The mean concentration level of UFP varies between below 8,000 ultrafine particles/cm
3
at the suburban background site and above 16,700 ultrafine particles/cm
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at the measurement station located next to a busy street canyon. At this particularly traffic-exposed measurement station, maximum concentrations of over 50,000 ultrafine particles/cm
3
were measured. The additional UFP load caused by intensive traffic volume during evening rush hour in connection with the unfavourable exchange processes in the street canyon can be quantified to concentrations of 14,000 ultrafine particles/cm
3
on average (compared to the immission situation of the urban background). An aggravating effect is brought about by inversion weather conditions in connection with air-polluted easterly winds, low wind speeds, lack of precipitation and very low mixing layer heights, such as over Augsburg at the end of January 2017, and cause peak concentrations of UFP.
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