scholarly journals Diurnal, weekly, seasonal and spatial variabilities in carbon dioxide flux in different urban landscapes in Sakai, Japan

2016 ◽  
Author(s):  
Masahito Ueyama ◽  
Tomoya Ando
Keyword(s):  
Rural Area ◽  
Eddy Covariance ◽  
Co2 Emissions ◽  
Air Temperature ◽  
Urban Areas ◽  
Suburban Area ◽  
Urban Park ◽  
Urban Landscapes ◽  
Co2 Fluxes ◽  
Urban Center

Abstract. To evaluate CO2 emissions in urban areas and their temporal and spatial variabilities, continuous measurements of CO2 fluxes were conducted using the eddy covariance method at three locations in Sakai, Osaka, Japan. Based on the flux footprint at the measurement sites, CO2 fluxes from the three sites were partitioned into five datasets representing a dense urban center, a moderately urban area, a suburb, an urban park, and a rural area. Distinct biological uptake of CO2 was observed in the suburb, urban park, and rural areas in the daytime, whereas high emissions were observed at dense and moderate urban areas in daytime. Weekday CO2 emissions in the dense urban center and suburban area were approximately 50 % greater than during weekend and holidays, but the other landscapes did not exhibit a clear weekly cycle. Seasonal variations in the urban park, rural area, and suburban area were influenced by vegetation activities, exhibiting the lowest daily emissions or even uptakes during summer months. In contrast, the dense and moderately urban areas exhibited higher emissions in winter and summer months, when emissions significantly increased as air temperature increased in summer and air temperature decreased in winter. Irrespective of the landcover type, all urban landscapes measured in this study acted as net annual CO2 sources, with emissions ranging from 0.5 to 4.9 kg C m−2 yr−1. The magnitude of the annual CO2 emissions was negatively correlated with green fraction; areas with a smaller green fraction had higher annual CO2 emissions. Upscaled flux estimates based on the green fraction indicated that the emissions for the entire city were 3.3 kg C m−2 yr−1, which is equivalent to 0.5 Tg C yr−1 or 1.8 Mt CO2 yr−1 based on the area of the city (149.81 km2). A network of eddy covariance measurements is a powerful tool to evaluate CO2 emissions from urban areas.

scholarly journals Diurnal, weekly, seasonal, and spatial variabilities in carbon dioxide flux in different urban landscapes in Sakai, Japan

2016 ◽  
Vol 16 (22) ◽  
pp. 14727-14740 ◽  
Author(s):  
Masahito Ueyama ◽  
Tomoya Ando
Keyword(s):  
Rural Area ◽  
Eddy Covariance ◽  
Co2 Emissions ◽  
Air Temperature ◽  
Urban Areas ◽  
Suburban Area ◽  
Urban Park ◽  
Urban Landscapes ◽  
Co2 Fluxes ◽  
Urban Center

Abstract. To evaluate CO2 emissions in urban areas and their temporal and spatial variability, continuous measurements of CO2 fluxes were conducted using the eddy covariance method at three locations in Sakai, Osaka, Japan. Based on the flux footprint at the measurement sites, CO2 fluxes from the three sites were partitioned into five datasets representing a dense urban center, a moderately urban area, a suburb, an urban park, and a rural area. A distinct biological uptake of CO2 was observed in the suburb, urban park, and rural areas in the daytime, whereas high emissions were observed in the dense and moderate urban areas in the daytime. Weekday CO2 emissions in the dense urban center and suburban area were approximately 50 % greater than emissions during weekends and holidays, but the other landscapes did not exhibit a clear weekly cycle. Seasonal variations in the urban park, rural area, and suburban area were influenced by photosynthetic uptake, exhibiting the lowest daily emissions or even uptake during the summer months. In contrast, the dense and moderately urban areas emitted CO2 in all seasons. CO2 emissions in the urban areas were high in the winter and summer months, and they significantly increased with the increase in air temperature in the summer and the decrease in air temperature in the winter. Irrespective of the land cover type, all urban landscapes measured in this study acted as net annual CO2 sources, with emissions ranging from 0.5 to 4.9 kg C m−2 yr−1. The magnitude of the annual CO2 emissions was negatively correlated with the green fraction; areas with a smaller green fraction had higher annual CO2 emissions. Upscaled flux estimated based on the green fraction indicated that the emissions for the entire city were 3.3 kg C m−2 yr−1, which is equivalent to 0.5 Tg C yr−1 or 1.8 Mt CO2 yr−1, based on the area of the city (149.81 km2). A network of eddy covariance measurements is useful for characterizing the spatial and temporal variations in net CO2 fluxes from urban areas. Multiple methods would be required to evaluate the rationale behind the fluxes and overcome the limitations in the future.

The movements and breeding site fidelity of the natterjack toad (Bufo calamita) in an urban park near Paris (France) with management recommendations

2006 ◽  
Vol 27 (4) ◽  
pp. 561-568 ◽  
Author(s):  
Aurélie Husté ◽  
Jean Clobert ◽  
Claude Miaud
Keyword(s):  
Urban Areas ◽  
Release Site ◽  
Breeding Site ◽  
Landscape Fragmentation ◽  
Urban Park ◽  
Breeding Period ◽  
Urban Landscapes ◽  
Breeding Sites ◽  
Bufo Calamita ◽  
Animal Populations

Abstract The isolation of animal populations due to urban activities provides a useful framework for studying the consequences of landscape fragmentation. We studied a population of natterjack toads (Bufo calamita) in an urban park near Paris, France. In 2001 and 2002 we used radio-tracking to estimate the terrestrial movements of adults around their breeding sites. Twenty-four toads were equipped with internal transmitters in 2001 to record movements during and after the breeding period. In 2002, 19 males were released at 300 and 380 meters from their breeding ponds. Natterjack toad movements around and outside their breeding ponds were reduced compared to previous observations on this species. The only exchanges that were observed occurred between closely neighbouring breeding sites. During a translocation experiment in 2002, 58% of the displaced males returned to their site of capture and this happened mainly during the breeding period. The remaining 42% stayed close to the release site. There was no exchange of males between distant breeding sites. Natterjack toad conservation needs to take into account the high fidelity to a breeding site and the reduced breeding dispersal and homing ability of these animals. Conservation biology in urban landscapes constitutes a specific urban ecology with specific concepts such as 'population area'. Information from this study can assist land managers in establishing protected areas of high habitat quality around breeding ponds in urban areas, and managing parks for the protection of amphibian populations, particularly by facilitating exchanges between available areas.

scholarly journals Thermo-hygrometric modeling using ENVI-met® software to an urban park in Cuiabá – Brazil

2018 ◽  
Vol 40 ◽  
pp. 37
Author(s):  
Thiago D'Orazio Joaquim ◽  
Jonathan Willian Zangeski Novais ◽  
Levi Pires de Andrade ◽  
Karyna De Andrade Carvalho Rosseti ◽  
Maricéia Tatiana Vilani ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Air Temperature ◽  
Urban Areas ◽  
Urban Park ◽  
Hot Climate ◽  
Two Phases ◽  
The City ◽  
City Park

Climate in urban areas, not under the effect of vegetation, was investigated and its benefits were observed in both vegetated and un-vegetated areas. The objective of this research was to model the air temperature and relative humidity using the Software ENVI-met® in an urban park in Cuiabá. The development of the methodology of this work involved two phases: survey (microclimate) and simulation. The microclimate survey was conducted through a mobile transect, for the periods of January 2014 to March 2014 (hot/wet) and July 2015 to September 2015 (hot/dry). The simulation was developed using ENVI-met® software during these two periods of the year. Generally maximizing the parameters, the ENVI-met® model for microclimate varied in the presence of too much vegetation. Simulations showed an increase in temperature and relative humidity in areas not surrounding the Mãe Bonifacia City Park, and this was particularly apparent in areas laid with asphalt and concrete. Vegetated parks play an important role in how hot climate thermoregulatory agents behave in the city of Cuiabá and the surrounding region.

scholarly journals Cross-validation of inferred daytime airborne CO<sub>2</sub> urban-regional scale surface fluxes with eddy-covariance observations and emissions inventories in Greater London

2013 ◽  
Vol 13 (5) ◽  
pp. 13465-13493 ◽  
Author(s):  
A. Font ◽  
C. S. B. Grimmond ◽  
J.-A. Morguí ◽  
S. Kotthaus ◽  
M. Priestman ◽  
...  
Keyword(s):  
Eddy Covariance ◽  
Urban Areas ◽  
Cross Validation ◽  
Regional Scale ◽  
Co2 Flux ◽  
Surface Fluxes ◽  
Co2 Fluxes ◽  
Wind Speeds ◽  
Mixing Ratios ◽  
Emissions Inventories

Abstract. Data obtained from eleven flight surveys on six days during October 2011 were used to characterize the urban CO2 dome in Greater London (GL) and to calculate CO2 fluxes at the city scale. Flights crossed GL along two transects (SW-NE and SSE-NNW) at an altitude of 360 m. Increments as high as 23 ppmv were measured. The maximum CO2 mixing ratios were localized over GL under low wind speeds, whereas a displacement of the urban plume downwind from the centre of the urban area occurred during high wind speeds. The urban-regional surface CO2 flux was calculated for four days by the Integrative Mass Boundary Layer (IMBL) method. The diurnal CO2 flux in GL obtained from the aircraft observations ranged from 46 to 104 μmol CO2 m−2 s−1 during the day time. The mean CO2 fluxes estimated from the IMBL method were statistically similar to those observed by eddy-covariance systems located in central London and a spatially integrated emissions inventory for GL. This study provides an important cross-validation of two independent measurement-based methods to infer the contribution of urban areas to climate change in terms of CO2 surface fluxes, both of which complement bottom-up emissions inventories. The uncertainties of fluxes estimated by the IMBL method are considered and the limits of implementation of atmospheric methods to infer city-scale fluxes are discussed.

scholarly journals A Model for Urban Biogenic CO<sub>2</sub> Fluxes: Solar-Induced Fluorescence for Modeling Urban biogenic Fluxes (SMUrF v1)

2020 ◽  
Author(s):  
Dien Wu ◽  
John C. Lin ◽  
Henrique F. Duarte ◽  
Vineet Yadav ◽  
Nicholas C. Parazoo ◽  
...  
Keyword(s):  
Eddy Covariance ◽  
Urban Areas ◽  
Fossil Fuel ◽  
Ecosystem Respiration ◽  
Growing Season ◽  
Carbon Fluxes ◽  
Co2 Fluxes ◽  
Biogenic Carbon ◽  
Urban Rural ◽  
Biogenic Fluxes

Abstract. When estimating fossil fuel carbon dioxide (FFCO2) emissions from observed CO2 concentrations, the accuracy can be hampered by biogenic carbon exchanges during the growing season even for urban areas where strong fossil fuel emissions are found. While biogenic carbon fluxes have been studied extensively across natural vegetation types, biogenic carbon fluxes within an urban area have been challenging to quantify due to limited observations and differences between urban versus rural regions. Here we developed a simple model representation, i.e., Solar-Induced Fluorescence (SIF) for Modeling Urban biogenic Fluxes ("SMUrF"), that estimates the gross primary production (GPP) and ecosystem respiration (Reco) over cities around the globe. Specifically, we leveraged space-based SIF, machine learning, eddy-covariance flux data, and additional remote sensing-based products, and developed algorithms to gap fill fluxes for urban areas. Grid-level hourly mean net ecosystem exchange (NEE) are extracted from SMUrF and evaluated against 1) non-gapfilled measurements at 67 eddy-covariance (EC) sites from FLUXNET during 2010–2014 (r > 0.7 for most data-rich biomes), 2) independent observations at two urban vegetation and two crop EC sites over Indianapolis from Aug 2017 to Dec 2018 (r = 0.75), and 3) an urban biospheric model based on fine-grained land cover classification within Los Angeles (r = 0.83). Moreover, we compared SMUrF-based NEE with inventory-based FFCO2 emissions over 40 cities and addressed the urban-rural contrast regarding both the magnitude and timing of CO2 fluxes. By examining a few summertime satellite tracks over four cities, we found that the urban-rural gradient in column CO2 (XCO2) anomalies due to NEE can sometimes reach ~ 0.5 ppm and be close to XCO2 enhancements due to FFCO2 emissions. With rapid advances in space-based measurements and increased sampling of SIF and CO2 measurements over urban areas, SMUrF can be useful for informing the biogenic CO2 fluxes over highly vegetated regions during the growing season.

scholarly journals Changes in Water Quality of the River das Antas as It Passes through Rural and Urban Areas

Urban Science ◽  
2021 ◽  
Vol 5 (1) ◽  
pp. 22
Author(s):  
Valdemir Antoneli ◽  
Manuel Pulido-Fernández ◽  
João Anésio Bednarz ◽  
Leonardo Brandes ◽  
Michael Vrahnakis ◽  
...  
Keyword(s):  
Rural Area ◽  
Urban Areas ◽  
Human Consumption ◽  
Rural And Urban Areas ◽  
Ph Values ◽  
Rural And Urban ◽  
Feasible Option ◽  
Decreasing Ph ◽  
The City

The catchment area of River das Antas (Irati, Paraná, Brazil) is of high importance both for human consumption and irrigation. Within Irati, this river passes through a rural area and through the city of Irati, crossing both poor and rich neighbourhoods. We selected three study areas downstream (a rural area, poor community, and rich neighbourhood) in which we measured turbidity, the concentration of sediments and pH during rainy days. Our results showed downstream trends of increasing turbidity and concentrations of sediments with decreasing pH. The values of turbidity and of concentration of sediments were significantly different in the rural area, while the pH values were significantly different between the three study areas. These findings highlight the effect of agricultural activities in the generation of sediments and turbidity. The—presumably expected—effects of organic urban waste from the poor neighbourhood were also detected in the pH values. We conclude that efforts should be made to ensure that land planning and training/education programmes on sustainable farming practices are undertaken by the authorities to reduce water pollution and its effects on water bodies during rainfall events, since paving streets is not a feasible option in the short term due to the high costs associated with this measure.

scholarly journals High Diversity in Urban Areas: How Comprehensive Sampling Reveals High Ant Species Richness within One of the Most Urbanized Regions of the World

Diversity ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 358
Author(s):  
François Brassard ◽  
Chi-Man Leong ◽  
Hoi-Hou Chan ◽  
Benoit Guénard
Keyword(s):  
Exotic Species ◽  
Urban Areas ◽  
Urban Landscapes ◽  
Dual Roles ◽  
Ant Communities ◽  
Continuous Increase ◽  
Tropical Regions ◽  
The World ◽  
Ant Diversity ◽  
The Vertical Distribution

The continuous increase in urbanization has been perceived as a major threat for biodiversity, particularly within tropical regions. Urban areas, however, may still provide opportunities for conservation. In this study focused on Macao (China), one of the most densely populated regions on Earth, we used a comprehensive approach, targeting all the vertical strata inhabited by ants, to document the diversity of both native and exotic species, and to produce an updated checklist. We then compared these results with 112 studies on urban ants to illustrate the dual roles of cities in sustaining ant diversity and supporting the spread of exotic species. Our study provides the first assessment on the vertical distribution of urban ant communities, allowing the detection of 55 new records in Macao, for a total of 155 ant species (11.5% being exotic); one of the highest species counts reported for a city globally. Overall, our results contrast with the dominant paradigm that urban landscapes have limited conservation value but supports the hypothesis that cities act as gateways for exotic species. Ultimately, we argue for a more comprehensive understanding of ants within cities around the world to understand native and exotic patterns of diversity.

scholarly journals “We Make Our Community”: Youth Forging Environmental Identities in Urban Landscapes

2021 ◽  
Vol 13 (14) ◽  
pp. 7736
Author(s):  
Erin Gallay ◽  
Alisa Pykett ◽  
Constance Flanagan
Keyword(s):  
High School Students ◽  
Urban Areas ◽  
Local Environment ◽  
Natural World ◽  
Urban Landscapes ◽  
Youth Of Color ◽  
School Students ◽  
Environmental Leadership ◽  
And Gender ◽  
The Impact

Insofar as race, class, and gender have profound effects on people’s environmental experiences, and consequently their activism, the environmental field needs more work on the environmental experiences and insights of groups whose voices have been missing, including youth of color who live in urban areas in the U.S. In this paper, we focus on African American and Latinx students engaged in environmental projects in their urban communities and the impact of such projects on promoting pro-environmental leadership, agency, and behavior. We draw from written reflections and focus group interviews of several hundred 4th–12th graders (majority middle- and high-school students) who participated in place-based civic science projects. Thematic analyses of student responses found that students engaged in work on local environmental issues cultivated an appreciation for the natural world and an understanding of human-nature interdependence and the ties between the local environment and their communities’ health. Through taking action with others in their communities, students viewed themselves as contributors to their communities and started to form environmental identities in ways that are not traditionally measured. Findings point to the need for forms of environmental education that are contextually grounded and centered on environmental justice in urban areas.

scholarly journals Quantifying the Independent Influences of Land Cover and Humidity on Microscale Urban Air Temperature Variation in Hot Summer: Methods of Path Analysis and Genetic SVR

Atmosphere ◽  
2020 ◽  
Vol 11 (12) ◽  
pp. 1377
Author(s):  
Weifang Shi ◽  
Nan Wang ◽  
Aixuan Xin ◽  
Linglan Liu ◽  
Jiaqi Hou ◽  
...  
Keyword(s):  
Relative Humidity ◽  
Land Cover ◽  
Path Analysis ◽  
Temperature Variation ◽  
Direct Effect ◽  
Air Temperature ◽  
Urban Areas ◽  
Support Vector ◽  
Urban Air ◽  
Air Temperatures

Mitigating high air temperatures and heat waves is vital for decreasing air pollution and protecting public health. To improve understanding of microscale urban air temperature variation, this paper performed measurements of air temperature and relative humidity in a field of Wuhan City in the afternoon of hot summer days, and used path analysis and genetic support vector regression (SVR) to quantify the independent influences of land cover and humidity on air temperature variation. The path analysis shows that most effect of the land cover is mediated through relative humidity difference, more than four times as much as the direct effect, and that the direct effect of relative humidity difference is nearly six times that of land cover, even larger than the total effect of the land cover. The SVR simulation illustrates that land cover and relative humidity independently contribute 16.3% and 83.7%, on average, to the rise of the air temperature over the land without vegetation in the study site. An alternative strategy of increasing the humidity artificially is proposed to reduce high air temperatures in urban areas. The study would provide scientific support for the regulation of the microclimate and the mitigation of the high air temperature in urban areas.

scholarly journals Consumption Rates and Use Patterns of Firewood and Charcoal in Urban and Rural Communities in Yedashe Township, Myanmar

Forests ◽  
2018 ◽  
Vol 9 (7) ◽  
pp. 429 ◽  
Author(s):  
Zar Win ◽  
Nobuya Mizoue ◽  
Tetsuji Ota ◽  
Tsuyoshi Kajisa ◽  
Shigejiro Yoshida
Keyword(s):  
Rural Communities ◽  
Environmental Impact ◽  
South Asia ◽  
Urban Area ◽  
Rural Area ◽  
Urban Areas ◽  
Fuel Use ◽  
Urban Households ◽  
Use Patterns ◽  
Consumption Rates

There is concern over the environmental impact of charcoal use for cooking in urban areas; however, studies have mainly been limited to Africa and South Asia. This investigation aimed to evaluate woodfuel consumption rates and patterns in an urban area in Yedashe Township, Myanmar and compared them with results from a rural area in the same township. From interviews with 66 urban households, it was evident that firewood and charcoal consumption rates in the urban area were about one-third and one-fourth, respectively, of those in the rural area. These low consumption rates were because of multiple-fuel use (mainly woodfuel and electricity) in the urban area in contrast to single-fuel use in the rural area. We estimated the forest area required to meet woodfuel demand of the whole township to be 3738 ha; that could decrease by almost 40% (1592 ha) if the single-fuel use in the rural area switched to the multiple-fuel methods used in the urban area. This study confirms that urbanization with an “energy stack” in multiple-fuel use, rather than an “energy ladder” from firewood to charcoal, could largely reduce the environmental impact on forests.

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