scholarly journals Temperature accounts for the biodiversity of a hyperdiverse group of insects in urban Los Angeles

2019 ◽  
Author(s):  
Terrence P. McGlynn ◽  
Emily K. Meineke ◽  
Christie A. Bahlai ◽  
Enjie Li ◽  
Emily A. Hartop ◽  
...  
Keyword(s):  
Los Angeles ◽  
Land Cover ◽  
Global Climate ◽  
Natural Areas ◽  
Worldwide Phenomenon ◽  
Urban Heat ◽  
Source Populations ◽  
The One ◽  
Urban Sites ◽  
Phorid Fly

AbstractThe urban heat island effect is a worldwide phenomenon that has been linked to species’ distributions and abundances in cities. However, effects of urban heat on biotic communities are nearly impossible to disentangle from effects of land cover in most cases because hotter urban sites also have less vegetation and more impervious surfaces than cooler sites within cities. We sampled phorid flies, one of the largest, most biologically diverse families of true flies (Insecta: Diptera: Phoridae), at 30 sites distributed within the central Los Angeles Basin, where we found that temperature and the density of urban land cover are decoupled. Abundance, richness, and community composition of phorids inside urban Los Angeles were most parsimoniously accounted for by mean air temperature in the week preceding sampling. Sites with intermediate mean temperatures had more phorid fly individuals and higher richness. Communities were more even at urban sites with lower minimum temperatures and sites located further away from natural areas, suggesting that communities separated from natural source populations may be more homogenized. Species composition was best explained by minimum temperature. Inasmuch as warmer areas within cities can predict future effects of climate change, phorid fly communities are likely to shift non-linearly under future climates in more natural areas. Exhaustive surveys of biotic communities within cities, such as the one we describe here, can provide baselines for determining the effects of urban and global climate warming as they intensify.

scholarly journals Temperature accounts for the biodiversity of a hyperdiverse group of insects in urban Los Angeles

2019 ◽  
Vol 286 (1912) ◽  
pp. 20191818 ◽  
Author(s):  
Terrence P. McGlynn ◽  
Emily K. Meineke ◽  
Christie A. Bahlai ◽  
Enjie Li ◽  
Emily A. Hartop ◽  
...  
Keyword(s):  
Los Angeles ◽  
Land Cover ◽  
Global Climate ◽  
Natural Areas ◽  
Worldwide Phenomenon ◽  
Urban Heat ◽  
Source Populations ◽  
The One ◽  
Urban Sites ◽  
Phorid Fly

The urban heat island effect is a worldwide phenomenon that has been linked to species distributions and abundances in cities. However, effects of urban heat on biotic communities are nearly impossible to disentangle from effects of land cover in most cases because hotter urban sites also have less vegetation and more impervious surfaces than cooler sites within cities. We sampled phorid flies, one of the largest, most biologically diverse families of true flies (Insecta: Diptera: Phoridae), at 30 sites distributed within the central Los Angeles Basin, where we found that temperature and the density of urban land cover are decoupled. Abundance, richness, and community composition of phorids inside urban Los Angeles were most parsimoniously accounted for by mean air temperature in the week preceding sampling. Sites with intermediate mean temperatures had more phorid fly individuals and higher richness. Communities were more even at urban sites with lower minimum temperatures and sites located further away from natural areas, suggesting that communities separated from natural source populations may be more homogenized. Species composition was best explained by minimum temperature. Inasmuch as warmer areas within cities can predict future effects of climate change, phorid fly communities are likely to shift nonlinearly under future climates in more natural areas. Exhaustive surveys of biotic communities within cities, such as the one we describe here, can provide baselines for determining the effects of urban and global climate warming as they intensify.

scholarly journals Cooling Effect of Different Land Cover Types: A Case Study in Xi’an and Xianyang, China

2021 ◽  
Vol 13 (3) ◽  
pp. 1099
Author(s):  
Yuhe Ma ◽  
Mudan Zhao ◽  
Jianbo Li ◽  
Jian Wang ◽  
Lifa Hu
Keyword(s):  
Land Cover ◽  
Surface Temperature ◽  
Urban Heat Island ◽  
Land Surface Temperature ◽  
Land Surface ◽  
Cooling Effect ◽  
Heat Island ◽  
Land Cover Types ◽  
Island Effect ◽  
Urban Heat

One of the climate problems caused by rapid urbanization is the urban heat island effect, which directly threatens the human survival environment. In general, some land cover types, such as vegetation and water, are generally considered to alleviate the urban heat island effect, because these landscapes can significantly reduce the temperature of the surrounding environment, known as the cold island effect. However, this phenomenon varies over different geographical locations, climates, and other environmental factors. Therefore, how to reasonably configure these land cover types with the cooling effect from the perspective of urban planning is a great challenge, and it is necessary to find the regularity of this effect by designing experiments in more cities. In this study, land cover (LC) classification and land surface temperature (LST) of Xi’an, Xianyang and its surrounding areas were obtained by Landsat-8 images. The land types with cooling effect were identified and their ideal configuration was discussed through grid analysis, distance analysis, landscape index analysis and correlation analysis. The results showed that an obvious cooling effect occurred in both woodland and water at different spatial scales. The cooling distance of woodland is 330 m, much more than that of water (180 m), but the land surface temperature around water decreased more than that around the woodland within the cooling distance. In the specific urban planning cases, woodland can be designed with a complex shape, high tree planting density and large planting areas while water bodies with large patch areas to cool the densely built-up areas. The results of this study have utility for researchers, urban planners and urban designers seeking how to efficiently and reasonably rearrange landscapes with cooling effect and in urban land design, which is of great significance to improve urban heat island problem.

scholarly journals Spatiotemporal Influence of Land Use/Land Cover Change Dynamics on Surface Urban Heat Island: A Case Study of Abuja Metropolis, Nigeria

2021 ◽  
Vol 10 (5) ◽  
pp. 272
Author(s):  
Auwalu Faisal Koko ◽  
Wu Yue ◽  
Ghali Abdullahi Abubakar ◽  
Akram Ahmed Noman Alabsi ◽  
Roknisadeh Hamed
Keyword(s):  
Land Use ◽  
Land Cover ◽  
Land Surface ◽  
Urban Expansion ◽  
Urban Heat Islands ◽  
Sustainable Land Use ◽  
Land Use Land Cover ◽  
Urban Centers ◽  
Rapid Urbanization ◽  
Urban Heat

Rapid urbanization in cities and urban centers has recently contributed to notable land use/land cover (LULC) changes, affecting both the climate and environment. Therefore, this study seeks to analyze changes in LULC and its spatiotemporal influence on the surface urban heat islands (UHI) in Abuja metropolis, Nigeria. To achieve this, we employed Multi-temporal Landsat data to monitor the study area’s LULC pattern and land surface temperature (LST) over the last 29 years. The study then analyzed the relationship between LULC, LST, and other vital spectral indices comprising NDVI and NDBI using correlation analysis. The results revealed a significant urban expansion with the transformation of 358.3 sq. km of natural surface into built-up areas. It further showed a considerable increase in the mean LST of Abuja metropolis from 30.65 °C in 1990 to 32.69 °C in 2019, with a notable increase of 2.53 °C between 2009 and 2019. The results also indicated an inverse relationship between LST and NDVI and a positive connection between LST and NDBI. This implies that urban expansion and vegetation decrease influences the development of surface UHI through increased LST. Therefore, the study’s findings will significantly help urban-planners and decision-makers implement sustainable land-use strategies and management for the city.

Media in crisis: Blowing hot and cold

1982 ◽  
Vol 72 (6B) ◽  
pp. S19-S28
Author(s):  
Ralph H. Turner
Keyword(s):  
Los Angeles ◽  
Interest Groups ◽  
The Other ◽  
World Views ◽  
Public Controversy ◽  
Earthquake Preparedness ◽  
Scientific World ◽  
Individual Household ◽  
The One ◽  
Organized Interest

abstract A 3-yr content analysis of all items dealing with earthquakes in six major Los Angeles newspapers and a review of television and radio treatment of earthquake topics in the same period, coupled with periodic surveys of popular understanding and attitudes toward the earthquake threat following announcement of the southern California uplift (Palmdale Bulge), lead to the identification of four media problems that contributed to the often erratic treatment of earthquake threat. First is the problem of newsworthiness, determining when and how to feature discussions of the continuing earthquake threat in the absence of either dramatic events or mobilized public controversy. Second is the problem of finding sources to provide a steady flow of material for use in preparing news items, in the absence of well-organized interest groups, especially those concerned with individual, household, and neighborhood earthquake preparedness. Third is the dilemma of how to balance the needs for alarm and reassurance, shocking people out of lethargy into action on the one hand versus trying to minimize unproductive anxiety and community disruption on the other hand. The fourth problem is communicating science when nonscientific world views are prevalent and merged to the point of confusion with scientific world views in popular thinking.

scholarly journals A prognostic pollen emissions model for climate models (PECM1.0)

2017 ◽  
Author(s):  
Matthew C. Wozniak ◽  
Allison Steiner
Keyword(s):  
United States ◽  
Land Cover ◽  
Climate Models ◽  
Climate Model ◽  
Vegetation Type ◽  
Global Climate ◽  
The United States ◽  
Global Climate Models ◽  
Pollen Counts ◽  
Surface Pollen

Abstract. We develop a prognostic model of Pollen Emissions for Climate Models (PECM) for use within regional and global climate models to simulate pollen counts over the seasonal cycle based on geography, vegetation type and meteorological parameters. Using modern surface pollen count data, empirical relationships between prior-year annual average temperature and pollen season start dates and end dates are developed for deciduous broadleaf trees (Acer, Alnus, Betula, Fraxinus, Morus, Platanus, Populus, Quercus, Ulmus), evergreen needleleaf trees (Cupressaceae, Pinaceae), grasses (Poaceae; C3, C4), and ragweed (Ambrosia). This regression model explains as much as 57 % of the variance in pollen phenological dates, and it is used to create a climate-flexible phenology that can be used to study the response of wind-driven pollen emissions to climate change. The emissions model is evaluated in a regional climate model (RegCM4) over the continental United States by prescribing an emission potential from PECM and transporting pollen as aerosol tracers. We evaluate two different pollen emissions scenarios in the model: (1) using a taxa-specific land cover database, phenology and emission potential, and (2) a PFT-based land cover, phenology and emission potential. The resulting surface concentrations for both simulations are evaluated against observed surface pollen counts in five climatic subregions. Given prescribed pollen emissions, the RegCM4 simulates observed concentrations within an order of magnitude, although the performance of the simulations in any subregion is strongly related to the land cover representation and the number of observation sites used to create the empirical phenological relationship. The taxa-based model provides a better representation of the phenology of tree-based pollen counts than the PFT-based model, however we note that the PFT-based version provides a useful and climate-flexible emissions model for the general representation of the pollen phenology over the United States.

scholarly journals Major projects in urban sites: Challenge of the Builders

2018 ◽  
Vol 149 ◽  
pp. 02003
Author(s):  
Ammar Dhouib
Keyword(s):  
Sustainable Development ◽  
Common Sense ◽  
Construction Projects ◽  
The Other ◽  
Observational Method ◽  
Urban Construction ◽  
Environmental Requirements ◽  
The One ◽  
Urban Sites ◽  
Displacement Measurements

Faced with the complexity of urban construction projects and difficulties in the field, engineers must, on the one hand, dimension with rigor and common sense the foundations with all the requirements of today of quality, conformity and respect of deadlines and budget and take into account, on the other hand, safety and environmental requirements and societal and sustainable development criteria, the purpose of this communication is to present concrete projects of foundations and excavation deep in geologically heterogeneous and highly urbanized sites, with monitoring and displacement measurements in order to compare predictions with reality and to promote the "observational method".

scholarly journals Towards Net Zero export credit: current approaches and next steps

2021 ◽  
Author(s):  
Thomas Hale ◽  
Andreas Klasen ◽  
Norman Ebner ◽  
Bianca Krämer ◽  
Anastasia Kantzelis
Keyword(s):  
Business Models ◽  
Global Climate ◽  
Export Credit ◽  
Public And Private ◽  
Climate Targets ◽  
Net Zero ◽  
The Many ◽  
The One ◽  
Investment Portfolios ◽  
Export Credit Agencies

As the world economy rapidly decarbonises to meet global climate goals, the export credit sector must keep pace. Countries representing over two-thirds of global GDP have now set net zero targets, as have hundreds of private financial institutions. Public and private initiatives are now working to develop new standards and methodologies for shifting investment portfolios to decarbonisation pathways based on science. However, export credit agencies (ECAs) are only at the beginning stages of this seismic transformation. On the one hand, the net zero transition creates risks to existing business models and clients for the many ECAs, while on the other, it creates a significant opportunity for ECAs to refocus their support to help countries and trade partners meet their climate targets. ECAs can best take advantage of this transition, and minimise its risks, by setting net zero targets and adopting credible plans to decarbonise their portfolios. Collaboration across the sector can be a powerful tool for advancing this goal.

scholarly journals Ecological impact evaluation of urban heat island in Dhaka city; a spatio-temporal approach

2021 ◽  
Author(s):  
Kazi Jihadur Rashid ◽  
Sumaia Islam ◽  
Mohammad Atiqur Rahman
Keyword(s):  
Land Cover ◽  
Urban Heat Island ◽  
Land Surface ◽  
Ecological Impact ◽  
Urban Life ◽  
Heat Island ◽  
Dhaka City ◽  
Ecological Conditions ◽  
Urban Heat ◽  
The Impact

Abstract Urban heat island (UHI) is one of the major causes for deteriorating ecology of the rapidly expanding Dhaka city in the changing climatic conditions. Although researchers have identified, characterized and modeled UHI in the study area, the ecological evaluation of UHI effect has not yet been focused. This study uses land surface normalization techniques such as urban thermal field variance (UTFVI) to quantify the impact of UHI and also identifies vulnerable UHI areas compared to land cover types. Landsat imageries from 1990 to 2020 were used at decadal intervals. Results of the study primarily show that intensified UHI areas have increased spatially from 33.1–40.9% in response to urban growth throughout the period of 1990 to 2020. Extreme surface temperature values above 31°C have also been shown in open soils in under-construction sites for future developmental purposes. UTFVI is categorized into six categories representing UHI intensity in relation to ecological conditions. Finally, comparative analysis between land use/land cover (LULC) with UTFVI shows that the ecological conditions deteriorate as the intensity of UHI increases in the area. The developed areas facing ecological threat have increased from 9.3–19.8% throughout the period. Effective mitigating measures such as increasing green surfaces and planned urbanization practices are crucial in this regard. This study would help policymakers to concentrate on controlling thermal exposure and on preserving sustainable urban life.

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