Bio-controlled thermostasis involving the sulfur cycle   总被引：4，自引：0，他引：4  

Glenn E. Shaw 《Climatic change》1983,5(3):297-303

The Gaia hypothesis proposed by Lovelock and Margulis presumes the existence of an unspecified biological means of ameliorating climate that has operated since the emergence of life 3500 Myr ago: Recently it was suggested that the mechanism of thermostasis may involve biospheric cycling of atmospheric carbon dioxide. We suggest an alternative hypothesis of biothermostasis operating through the sulfur cycle, rather than the carbon cycle. The mechanism would operate by altering planetary albedo through the selective creation of biospheric organic sulfide gases which go on to metamorphize into submicron particles and introduce cooling. In contrast to the carbon-cycle mechanism, sulfur-based cooling would have the ability to ameliorate climate well into the future, in principle over stellar Main Sequence time intervals. The main feature of interest is that the S cycle represents a particularly favorable thermodynamic pathway, involving three to four orders of magnitude less mass of active material cycled through the biospheric-atmospheric system (in response to a given temperature-imposed stress) than would be the case for a greenhouse gas hypothesis. There is no evidence that the suggested biospheric controlled particle-albedo change mechanism is actually operating, but we speculate that the probability of its rising importance and perhaps eventual dominance will improve when the partial pressure of atmospheric CO₂ drops low enough to impose stress on metabolic processes. The intriguing thing about the process is its extremely high efficiency.  相似文献   

Global Landscapes: Teaching Globalization through Responsive Mobile Map Design     

Robert Roth  Stephen Young  Chelsea Nestel  Carl Sack  Brian Davidson  Julia Janicki 《The Professional geographer》2018,70(3):395-411

This article reports on the design and evaluation of Global Madison, a mobile map designed to support teaching and learning about globalization using Madison, Wisconsin, as a situated classroom. Our experience of place increasingly is mediated by mobile devices, opening new opportunities and challenges for research, industry, and education. Despite this rising popularity, few guidelines exist for creating and using mobile maps. Following tenets of user-centered design studies, we conducted two mixed-method evaluations of Global Madison to improve the tool and generate design insights that are potentially transferable to similar mobile mapping contexts: 244 students participated in an online survey after completing the tour and eighteen students were observed in the field. The evaluations generated new design considerations for mobile maps supporting situated learning, include: focus on critical issues that might leave students stranded, append location-based services with traditional mapping, enforce cognitive association between map and landscape, supply a consistent feed of information for new learners, encourage collaborative learning in the landscape, and promote student safety above all else.  相似文献   

Fine-grained prediction of urban population using mobile phone location data     

Jie Chen  Shih-Lung Shaw  Feng Lu  Mingxiao Li  Shifen Cheng 《International journal of geographical information science》2018,32(9):1770-1786

Fine-grained prediction of urban population is of great practical significance in many domains that require temporally and spatially detailed population information. However, fine-grained population modeling has been challenging because the urban population is highly dynamic and its mobility pattern is complex in space and time. In this study, we propose a method to predict the population at a large spatiotemporal scale in a city. This method models the temporal dependency of population by estimating the future inflow population with the current inflow pattern and models the spatial correlation of population using an artificial neural network. With a large dataset of mobile phone locations, the model’s prediction error is low and only increases gradually as the temporal prediction granularity increases, and this model is adaptive to sudden changes in population caused by special events.  相似文献   

Climate Change driven evolution of hazards to Europe’s transport infrastructure throughout the twenty-first century     

Christoph?MatullaEmail author  Brigitta?Hollósi  Konrad?Andre  Julia?Gringinger  Barbara?Chimani  Joachim?Namyslo  Tobias?Fuchs  Markus?Auerbach  Carina?Herrmann  Brigitte?Sladek  Heimo?Berghold  Roland?Gschier  Eva?Eichinger-Vill 《Theoretical and Applied Climatology》2018,131(1-2):227-243

Air circulation due to the urban heat island (UHI) effect can influence the dispersion of air pollutants in a metropolis. This study focusses on the influence of the UHI effect on particulate matter (PM; including PM_2.5 and PM_2.5–10) between May and September 2010–2012 in the Taipei basin. Meteorological and PM data were obtained from the sites, owned by the governmental authorities. The analysis was carried out using t test, relative indices (RIs), Pearson product–moment correlation and stepwise regression. The results show that the RI values for PM were the highest at moderate UHI intensity (MUI; 2 °C ≤ UHI < 4 °C) rather than at strong UHI intensity (SUI; 4 °C ≤ UHI) during the peak time for anthropogenic emissions (20:00 LST). Neither the accumulation of PM nor the surface convergence occurred in the hot centre, as shown by the case study. At MUI, more than 89 % of the synoptic weather patterns showed that the weather was clear and hot or that the atmosphere was stable. The variation in PM was associated with horizontal and vertical air dispersion. Poor horizontal air dispersion, with subsidence, caused an increase in PM at MUI. However, the updraft motion diluted the PM at SUI. The stepwise regression models show that the cloud index and surface air pressure determined the variation in PM_2.5–10, while cloud index, wind speed and mixing height influenced the variation in PM_2.5. In conclusion, a direct relationship between UHI effect and PM was not obvious.  相似文献   

Increased photosynthesis compensates for shorter growing season in subarctic tundra—8 years of snow accumulation manipulations     

Julia Bosiö  Christian Stiegler  Margareta Johansson  Herbert N. Mbufong  Torben R. Christensen 《Climatic change》2014,127(2):321-334

This study was initiated to analyze the effect of increased snow cover on plant photosynthesis in subarctic mires underlain by permafrost. Snow fences were used to increase the accumulation of snow on a subarctic permafrost mire in northern Sweden. By measuring reflected photosynthetic active radiation (PAR) the effect of snow thickness and associated delay of the start of the growing season was assessed in terms of absorbed PAR and estimated gross primary production (GPP). Six plots experienced increased snow accumulation and six plots were untreated. Incoming and reflected PAR was logged hourly from August 2010 to October 2013. In 2010 PAR measurements were coupled with flux chamber measurements to assess GPP and light use efficiency of the plots. The increased snow thickness prolonged the duration of the snow cover in spring. The delay of the growing season start in the treated plots was 18 days in 2011, 3 days in 2012 and 22 days in 2013. Results show higher PAR absorption, together with almost 35 % higher light use efficiency, in treated plots compared to untreated plots. Estimations of GPP suggest that the loss in early season photosynthesis, due to the shortening of the growing season in the treatment plots, is well compensated for by the increased absorption of PAR and higher light use efficiency throughout the whole growing seasons. This compensation is likely to be explained by increased soil moisture and nutrients together with a shift in vegetation composition associated with the accelerated permafrost thaw in the treatment plots.  相似文献   

Evaluation of a Movie Theater Advertisement Campaign to Promote Behaviors that Prevent Spread of Aquatic Invasive Species     

Bret R. Shaw  Allison Howell  Ken Genskow 《社会与自然资源》2014,27(7):768-776

One of the primary causes of the spread of aquatic invasive species (AIS) is boaters and anglers who move between bodies of water. Engaging with recreational boaters and anglers to encourage preventative behaviors is crucial for managing the spread of AIS. The use of cinema advertising for disseminating pro-environmental messages is a relatively novel and understudied outreach strategy. To explore this approach, an AIS-related public service announcement was placed in the preshow advertising at a movie theater in north central Wisconsin. Movie patrons were surveyed as they left the theater to determine demographic, AIS awareness, advertising exposure, and recall information. The results of this study suggest movie theater advertising is a potentially efficacious medium for pro-environmental outreach efforts.  相似文献   

Free advanced modeling and remote-sensing techniques for wetland watershed delineation and monitoring     

Javier Martínez-López  María F. Carreño  José A. Palazón-Ferrando  Julia Martínez-Fernández  Miguel A. Esteve 《International journal of geographical information science》2014,28(8):1610-1625

Watershed scale studies focusing on hydrological pressures influencing freshwater ecosystem dynamics are necessary for the establishment of suitable wetland ecological indicators. Enhanced and reproducible methods for watershed modeling and land-cover assessment are thus essential tools for wetland monitoring and management. However, few integrated studies propose advanced open source methodologies for watershed modeling and assessment. In this study, a set of GIS methodological tools was applied and further developed in order to delineate wetland watersheds and map their land-cover changes over time. Watersheds draining to 11 semiarid Mediterranean saline wetlands were delimited and map algebra operations were applied on the digital elevation model in the Campo de Cartagena coastal plain to enhance watershed delimitation. land-use/land-cover maps of wetland watersheds were obtained for years 1987 and 2008 by means of supervised classification of Landsat images. A set of four spectral indices was included in the classification analysis using a combination of bands in order to improve the discrimination of vegetation, water bodies, infrastructure, and bare soil. An iterative classification procedure based on maximum likelihood and random selection of training areas was applied. Contextual information based on automatic image segmentation of Landsat scenes was also included as ancillary layers. Watershed areas obtained ranged from 70 to 17,000 ha and delineation was improved in the Campo de Cartagena coastal plain. The proposed image classification methodology showed high accuracies and improved standard classification techniques. The proposed methodology is based on free and open source tools, which makes it broadly applicable.  相似文献   

A participatory systems approach to understanding climate adaptation needs     

Helen Ross  Sylvie Shaw  David Rissik  Neil Cliffe  Susie Chapman  Vanessa Hounsell  James Udy  Nghia Trong Trinh  Jess Schoeman 《Climatic change》2015,129(1-2):27-42

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The magnetic field in the solar atmosphere     

Thomas?WiegelmannEmail author  Julia?K.?Thalmann  Sami?K.?Solanki 《Astronomy and Astrophysics Review》2014,22(1):78

This publication provides an overview of magnetic fields in the solar atmosphere with the focus lying on the corona. The solar magnetic field couples the solar interior with the visible surface of the Sun and with its atmosphere. It is also responsible for all solar activity in its numerous manifestations. Thus, dynamic phenomena such as coronal mass ejections and flares are magnetically driven. In addition, the field also plays a crucial role in heating the solar chromosphere and corona as well as in accelerating the solar wind. Our main emphasis is the magnetic field in the upper solar atmosphere so that photospheric and chromospheric magnetic structures are mainly discussed where relevant for higher solar layers. Also, the discussion of the solar atmosphere and activity is limited to those topics of direct relevance to the magnetic field. After giving a brief overview about the solar magnetic field in general and its global structure, we discuss in more detail the magnetic field in active regions, the quiet Sun and coronal holes.  相似文献   

Characterisation of the intra-annual rainfall and its evolution (1837–2010) in the southwest of the Iberian Peninsula     

Leoncio García-Barrón  Julia Morales  Arturo Sousa 《Theoretical and Applied Climatology》2013,114(3-4):445-457

Variability in precipitation affects annual total records and causes instability in rainfall distribution throughout the year. Our aim in this study was to develop a procedure, based on pluviometric centralisation and dispersion parameters, that is able to characterise rainfall distribution throughout a year of precipitation in a unique, condensed and precise manner. This enabled the evolution of intra-annual precipitation from 1837 to 2010 in the southwest of the Iberian Peninsula to be determined. The obtained results showed irregular oscillations of the parameters during the selected period. Specifically, patterns of precipitation in recent decades revealed the following differentiating features: the displacement of the most intense rainy periods in autumn with a consequent decrease in precipitation in spring, and more erratic distribution throughout the year with an increase of the frequency of intra-annual dispersion peaks.  相似文献