scholarly journals Urbanization Impacts on Vegetation Phenology in China

2018 ◽  
Vol 10 (12) ◽  
pp. 1905 ◽  
Author(s):  
Qiang Ren ◽  
Chunyang He ◽  
Qingxu Huang ◽  
Yuyu Zhou
Keyword(s):  
Rural Areas ◽  
Land Surface ◽  
Urban Areas ◽  
Growing Season ◽  
Vegetation Phenology ◽  
Rapid Urbanization ◽  
Climate Zone ◽  
Growing Season Length ◽  
Impact Of Urbanization ◽  
The Impact

Urbanization can affect the ecological processes, local climate and human health in urban areas by changing the vegetation phenology. In the past 20 years, China has experienced rapid urbanization. Thus, it is imperative to understand the impact of urbanization on vegetation phenology in China. In this study, we quantitatively analyzed the impact of urbanization on vegetation phenology at the national and climate zone scales using remotely sensed data. We found that the start of the growing season (SOS) was advanced by approximately 2.4 days (P < 0.01), and the end of the growing season (EOS) was delayed by approximately 0.7 days (P < 0.01) in the urban areas compared to the rural areas. As a result, the growing season length (GSL) was extended by approximately 3.1 days (P < 0.01). The difference in the SOS and GSL between the urban and rural areas increased from 2001 to 2014, with an annual rate of 0.2 days (R2 = 0.39, P < 0.05) and 0.2 days (R2 = 0.31, P < 0.05), respectively. We also found that the impact of urbanization on vegetation phenology varied among different vegetation types at the national and climate zone levels (P < 0.05). The SOS was negatively correlated with land surface temperature (LST), with a correlation coefficient of −0.24 (P < 0.01), and EOS and GSL were positively correlated with LST, with correlation coefficients of 0.56 and 0.44 (P < 0.01), respectively. The improved understanding of the impact of urbanization on vegetation phenology from this study will be of great help for policy-makers in terms of developing relevant strategies to mitigate the negative environmental effects of urbanization in China.

scholarly journals The impact of urbanization expansion on agricultural land in Ethiopia: A review

2020 ◽  
Vol 8 (4) ◽  
pp. 73-80
Author(s):  
Assefa Ayele ◽  
Kassa Tarekegn
Keyword(s):  
Urban Areas ◽  
Agricultural Land ◽  
Urban Expansion ◽  
Rural Livelihoods ◽  
Vital Role ◽  
Rapid Urbanization ◽  
Economic Resource ◽  
House Construction ◽  
Impact Of Urbanization ◽  
The Impact

AbstractIn a country like Ethiopia where the vast majority of the populations are employed in agriculture, land is an important economic resource for the development of rural livelihoods. Agricultural land in peri-urban areas is, however, transformed into built-up regions through horizontal urban expansion that has an effect on land use value. In recent years Ethiopia has been experiencing rapid urbanization, which has led to an ever-increasing demand for land in peri-urban areas for housing and other nonagricultural activities that pervades agricultural land. There is a high demand for informal and illegal peri-urban land which has been held by peri-urban farmers, and this plays a vital role in the unauthorized and sub-standard house construction on agricultural land. This urbanization has not been extensively reviewed and documented. In this review an attempt has been made to assess the impacts of rapid urbanization on agricultural activities. Urban expansion has reduced the areas available for agriculture, which has seriously impacted upon peri-urban farmers that are often left with little or no land to cultivate and which has increased their vulnerability. Housing encroachments have been observed to be uncontrolled due to a weak government response to the trend of unplanned city expansion. This has left peri-urban farmers exposed to the negative shocks of urbanization because significant urbanization-related agricultural land loss has a positive correlation with grain production decrease. Appropriate governing bodies should control urban development in order to control the illegal and informal spread of urbanization on agricultural land that threatens food production.

scholarly journals Thematic Maps of the Impact of Urbanization and Socioeconomic Factors on the Distribution of the Incidence of Cutaneous Leishmaniasis Cases in Sefrou Province, Central North of Morocco (2007–2011)

2020 ◽  
Vol 2020 ◽  
pp. 1-8
Author(s):  
Fatima Zahra Talbi ◽  
Nordine Nouayti ◽  
Hajar El Omari ◽  
Mohamed Najy ◽  
Khadija Lahouiti ◽  
...  
Keyword(s):  
Statistical Analysis ◽  
Socioeconomic Factors ◽  
Cutaneous Leishmaniasis ◽  
Rural Areas ◽  
Urban Areas ◽  
Pearson Correlation ◽  
Correlation Study ◽  
Poverty Rate ◽  
Impact Of Urbanization ◽  
The Impact

Background. Leishmaniases are vector-borne diseases with health risks. They cause a big health problem. These parasitic diseases are transmitted by the parasite of the genus Leishmania through sandflies. Objective. The aim of this work is to study the distribution of the incidence of cutaneous leishmaniasis (CL) cases and the impact of urbanization and socioeconomic factors and their effects as leishmaniasis risk factors. Methods. We conducted a retrospective study of CL cases collected at the level of Sefrou Province during the period from 2007 to 2011. The data was collected from registers of the Medical Delegation of Sefrou Province. The socioeconomic data, namely, the poverty rate, the popular density, and the type of environment (urban/rural) of Sefrou Province, were obtained from the High Commission for Planning. Statistical analysis was performed by SPSS software (version 20). The data were registered in a Microsoft Excel 2010 file. Statistical analysis was based on one-way analysis of variance (ANOVA), and then a correlation study was carried out (Pearson correlation). The results were considered significant when p was less than 0.05. The database was analyzed by QGIS 2.18, which is open source software. Results. A total of 349 cases of CL were collected at Sefrou Province from 2007 to 2011. A percentage of 49% of the cases come from urban areas, while 51% of the cases come from rural areas. In the statistical analysis, the division of the incidence of CL cases was found to be significantly associated only with urbanization. For the other factors, the number of people or the poverty rate is not taken into account in the incidence dynamics. Conclusion. This study may be useful for the implementation of future adequate measures and controls. Getting rid of leishmaniasis requires a comprehensive approach by acting on the sources of contamination through good continuous surveillance, appropriate management, effective vector control, and awareness-raising strategies.

THE IMPACT OF URBANIZATION ON MURDER RATES AND ON THE GEOGRAPHY OF HOMICIDE IN ENGLAND AND WALES, 1780–1850

2010 ◽  
Vol 53 (3) ◽  
pp. 671-698 ◽  
Author(s):  
PETER KING
Keyword(s):  
Rural Areas ◽  
Rapid Urbanization ◽  
Homicide Rates ◽  
England And Wales ◽  
Large Cities ◽  
Methodological Problems ◽  
Urban And Rural Areas ◽  
And Migration ◽  
Impact Of Urbanization ◽  
The Impact

ABSTRACTAlthough higher murder rates have traditionally been associated with large cities, this view has recently been challenged by several historians who have argued that ‘homicide rates were negatively correlated with urbanisation and industrialisation’, and this is rapidly becoming the new consensus. By exploring the geography of homicide rates for one area undergoing rapid urbanization and industrialization – England and Wales, 1780–1850 – this article challenges this new view and re-assesses the relationship between recorded homicide rates and both modernization and urbanization. After discussing the methodological problems involved in using homicide statistics, it focuses mainly on the first fifteen years for which detailed county-based data is available – 1834–48 – as well as looking at the more limited late eighteenth-century and early nineteenth-century evidence. This data raises fundamental questions about the links historians have recently made between urbanization and low homicide rates, since the remote rural parts of England and Wales generally had very low recorded murder rates while industrializing and rapidly urbanizing areas such as Lancashire had very high ones. Potential explanations for these systematic and large variations between urban and rural areas – including the impact of age structures and migration patterns – are then explored.

scholarly journals Improved and promising fecal sludge sanitizing methods: treatment of fecal sludge using resource recovery technologies

2021 ◽  
Author(s):  
Abraham Amenay Zewde ◽  
Zifu Li ◽  
Zhou Xiaoqin
Keyword(s):  
Rural Areas ◽  
Urban Areas ◽  
Resource Recovery ◽  
Rapid Urbanization ◽  
Sanitation Services ◽  
Fecal Sludge ◽  
End Products ◽  
Wastewater Systems ◽  
Treatment Facilities ◽  
The Impact

Abstract The global challenges that face sustainable sanitation services in developing countries are the lack of fecal sludge management; this is due to the rapid urbanization and population growth as it generates enormous quantities of fecal sludge. The extensive use of unimproved sanitation technologies is one of the main reasons for environmental and public health concerns. In dispersed rural areas, isolated slums or in urban areas where a sewerage system is costly, decentralized wastewater system can be used. Therefore centralized management of decentralized wastewater systems along with proper institutional framework treatment of fecal sludge can be used to enhance the economies of developing counties from resource recovery. The discovery of new ways to inactivate pathogens contained in human waste is key in improving access to sanitation worldwide and reducing the impact of conventional waste management processes on the environment. The entire FS management system should include on-site sanitary treatment methods, collection, and transportation of FS, treatment facilities as well as resource recovery or disposal of the treated end products. This review paper addresses the hygienization of fecal sludge and improved treatment technologies for safe reuse or disposal of the end products and the significant economic revenues attained from the treatments of fecal sludge.

A new approach for improving representation of boreal forest phenology in land surface models

2021 ◽  
Author(s):  
Titta Majasalmi ◽  
Miina Rautiainen
Keyword(s):  
Land Surface ◽  
Spatial Scales ◽  
Growing Season ◽  
Vegetation Phenology ◽  
Threshold Values ◽  
Conifer Forest ◽  
Season Length ◽  
New Approach ◽  
Growing Season Length ◽  
Satellite Sensors

&lt;p&gt;In a boreal region, terrestrial vegetation carbon balance is controlled by vegetation phenology, which steers photosynthesis, respiration, and biomass turnover processes. In the absence of a full mechanistic understanding of environmental processes controlling vegetation phenology (i.e. senescence, dormancy, chilling), empirically-based models are often applied. These models are typically based on greenness proxies (obtained from satellite data) with fixed amplitude thresholds (e.g. of 15%, 50%, 90%) to determine timings of different phenological events. Yet, it is not known how well those percentiles correspond with the timings of events such as the green-up and the senescence. Especially in the boreal region, estimating timings of different phenological events across large spatial scales remains challenging due to the lack of sufficient ground validation data representative of both forest tree canopy and forest understory species compositions, which are both observed by a satellite sensor. From the land surface modeling perspective, there is a need to develop methods to improve the mapping of phenological events for prudent prediction of the land vegetation-atmosphere interactions under different future climates. In this study, we developed a new approach for calibrating boreal forest greenness amplitude thresholds which indicate timings of different phenological transitions in satellite data. The new approach to calibrate satellite-based greenness thresholds was demonstrated using boreal Finland as a case study area (60-70 N&amp;#176;). Using the approach, we computed satellite-based phenological events and compared them to ground reference data on temperature from a network of meteorological stations across Finland. We also investigated the effects of using different phenological events or ground reference temperature data on estimated growing season length. Results showed that while the standard greenness amplitude threshold values corresponded fairly well with the growing season start, the autumn phenology was not well captured by the standard greenness amplitude threshold values, which has direct impact on growing season length. Based on our data, boreal conifer forest senescence (default is 90%) corresponds with the timing of greenness amplitude of ~45%, while boreal conifer forest dormancy (default is 15%) corresponds with the timing of reaching greenness amplitude of ~0%. The approach allows flexible application across spatial scales (i.e. point or grid) and different satellite sensors, and may be combined with any land cover product, and it provides a meaningful linking between surface temperature data and seasonal reflectance measured by satellite sensors.&lt;/p&gt;

scholarly journals Urban Thermal Environment and Heat Island in Ho Chi Minh City, Vietnam from Remote Sensing Data

2017 ◽  
Author(s):  
Van Tran Thi ◽  
Bao Ha Duong Xuan ◽  
Mai Nguyen Thi Tuyet
Keyword(s):  
Surface Temperature ◽  
Urban Heat Island ◽  
Rural Areas ◽  
Land Surface ◽  
Urban Areas ◽  
Ho Chi Minh City ◽  
Heat Island ◽  
Urban Heat ◽  
Surface Urban Heat Island ◽  
The Impact

In urban area, one of the great problem is the rise of temperature, which leads to form the urban heat island effect. This paper refers to the trend of the urban surface temperature extracted from the Landsat images from which to consider changes in the formation of surface urban heat island for the north of Ho Chi Minh city in period 1995-2015. Research has identified land surface temperature from thermal infrared band, according to the ability of the surface emission based on characteristics of normalized difference vegetation index NDVI. The results showed that temperature fluctuated over the city with a growing trend and the gradual expansion of the area of the high-temperature zone towards the suburbs. Within 20 years, the trend of the formation of surface urban heat island with two typical locations showed a clear difference between the surface temperature of urban areas and rural areas with space expansion of heat island in 4 times in 2015 compared to 1995. An extreme heat island located in the inner city has an area of approximately 18% compared to the total area of the region. Since then, the solution to reduce the impact of urban heat island has been proposed, in order to protect the urban environment and the lives of residents in Ho Chi Minh City becoming better

scholarly journals The regional impact of urban emissions on air quality in Europe: the role of the urban canopy effects

2021 ◽  
Author(s):  
Peter Huszar ◽  
Jan Karlický ◽  
Jana Marková ◽  
Tereza Nováková ◽  
Marina Liaskoni ◽  
...  
Keyword(s):  
Air Quality ◽  
Rural Areas ◽  
Land Surface ◽  
Urban Areas ◽  
Regional Climate ◽  
Regional Scale ◽  
Urban Canopy ◽  
Near Surface ◽  
Urban Emissions ◽  
The Impact

Abstract. Urban areas are hot-spots of intense emissions and they influence air-quality not only locally but on regional or even global scales. The impact of urban emissions over different scales depends on the dilution and chemical transformation of the urban plumes which are governed by the local and regional scale meteorological conditions. These are influenced by the presence of urbanized land-surface via the so called urban canopy meteorological forcing (UCMF). In this study, we investigate for selected central European cities (Berlin, Budapest, Munich, Prague, Vienna and Warsaw), how the urban emission impact (UEI) is modulated by the UCMF for present day climate conditions (2015–2016) using three regional climate-chemistry models: the regional climate models RegCM and WRF-Chem (its meteorological part), the chemistry transport model CAMx coupled to either RegCM and WRF and the “chemical” component of WRF-Chem. The UCMF was calculated by replacing the urbanized surface by rural one while the UEI was estimated by removing all anthropogenic emissions from the selected cities. We analyzed the urban emissions induced changes of near surface concentrations of NO2, O3 and PM2.5. We found increases of NO2 and PM2.5 concentrations over cities by 4–6 ppbv, and 4–6 μgm−3, respectively meaning that about 40–60 % and 20–40 % of urban concentrations of NO2 and PM2.5 are caused by local emissions and the rest is the result of emissions from surrounding rural areas. We showed that if UCMF is included, the UEI of these pollutants is about 40–60 % smaller, or in other words, the urban emission impact is overestimated if urban canopy effects are not taken into account. In case of ozone, models due to UEI usually predict decreases around −2 to −4 ppbv (about 10–20 %), which is again smaller if UCMF is considered (by about 60 %). We further showed that the impact on extreme (95th percentile) air-pollution is much stronger, as well as the modulation of UEI is larger for such situations. Finally, we evaluated the contribution of the urbanization induced modifications of vertical eddy-diffusion to the modulation of UEI, and found that it alone is able to explain the modelled decrease of the urban emission impact if the effects of UCMF are considered. In summary, our results showed that the meteorological changes resulting from urbanization have to be included in regional model studies if they intend to quantify the regional fingerprint of urban emissions. Ignoring these meteorological changes can lead to strong overestimation of UEI.

scholarly journals Evaluation of Urban Heat Island (UHI) Using Satellite Images in Densely Populated Cities of South Asia

Earth ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 86-110
Author(s):  
Manisha Maharjan ◽  
Anil Aryal ◽  
Bijay Man Shakya ◽  
Rocky Talchabhadel ◽  
Bhesh Raj Thapa ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Urban Heat Island ◽  
South Asia ◽  
Land Surface ◽  
Urban Areas ◽  
Well Being ◽  
Heat Island ◽  
Rapid Urbanization ◽  
Urban Heat ◽  
The Impact

Rapid Urbanization, and other anthropogenic activities, have amplified the change in land-use transition from green space to heat emission in built-up areas globally. As a result, there has been an increase in the land surface temperature (LST) causing the Urban Heat Island (UHI) effect, particularly in large cities. The UHI effect poses a serious risk to human health and well-being, magnified in large developing cities with limited resources to cope with such issues. This study focuses on understanding the UHI effect in Kathmandu Valley (KV), Delhi, and Dhaka, three growing cities in South Asia. The UHI effect was evaluated by analyzing the UHI intensity of the city with respect to the surroundings. We found that the central urban area, of all three cities, experienced more heat zones compared to the peri-urban areas. The estimated average surface temperature ranged from 21.1 ∘C in March 2014 to 32.0 ∘C in June 2015 in KV, while Delhi and Dhaka experienced surface temperature variation from 29.7 ∘C in June 2017 to 40.2 ∘C in June 2019 and 23.6 ∘C in March 2017 to 33.2 ∘C in March 2014, respectively. Based on magnitude and variation of LST, highly built-up central KV showed heat island characteristics. In both Delhi and Dhaka, the western regions showed the UHI effect. Overall, this study finds that the UHI zones are more concentrated near the urban business centers with high population density. The results suggest that most areas in these cities have a rising LST trend and are on the verge of being UHI regions. Therefore, it is essential that further detailed assessment is conducted to understand and abate the impact of the temperature variations.

scholarly journals Vegetation Phenology Influenced by Rapid Urbanization of The Yangtze Delta Region

2020 ◽  
Vol 12 (11) ◽  
pp. 1783 ◽  
Author(s):  
Haiyong Ding ◽  
Luming Xu ◽  
Andrew J. Elmore ◽  
Yuli Shi
Keyword(s):  
Climate Change ◽  
Time Series ◽  
Land Surface ◽  
Urban Areas ◽  
Vegetation Phenology ◽  
Rapid Urbanization ◽  
Spring Phenology ◽  
Surface Temperatures ◽  
Land Surface Temperatures ◽  
Over Time

Impacts of urbanization and climate change on ecosystems are widely studied, but these drivers of change are often difficult to isolate from each other and interactions are complicated. Ecosystem responses to each of these drivers are perhaps most clearly seen in phenology changes due to global climate change (warming climate) and urbanization (heat island effect). The phenology of vegetation can influence many important ecological processes, including primary production, evapotranspiration, and plant fitness. Therefore, evaluating the interacting effects of urbanization and climate change on vegetation phenology has the potential to provide information about the long-term impact of global change. Using remotely sensed time series of vegetation on the Yangtze River Delta in China, this study evaluated the impacts of rapid urbanization and climate change on vegetation phenology along an urban to rural gradient over time. Phenology markers were extracted annually from an 18-year time series by fitting the asymmetric Gaussian function model. Thermal remote sensing acquired at daytime and nighttime was used to explore the relationship between land surface temperature and vegetation phenology. On average, the spring phenology marker was 9.6 days earlier and the autumn marker was 6.63 days later in urban areas compared with rural areas. The spring phenology of urban areas advanced and the autumn phenology delayed over time. Across space and time, warmer spring daytime and nighttime land surface temperatures were related to earlier spring, while autumn daytime and nighttime land surface temperatures were related to later autumn phenology. These results suggest that urbanization, through surface warming, compounds the effect of climate change on vegetation phenology.

Impact of Rapid Urbanization and Climate Change on Agricultural Productivity in Africa

2016 ◽  
pp. 416-426
Author(s):  
Mutisya Emmanuel ◽  
Lilian Muasa ◽  
Chiahsin Chen ◽  
Florence Mutisya ◽  
Ram Avtar
Keyword(s):  
Climate Change ◽  
Rapid Growth ◽  
Rural Areas ◽  
Urban Areas ◽  
Negative Impact ◽  
Agricultural Productivity ◽  
Well Being ◽  
Rapid Urbanization ◽  
Vulnerability To Climate Change ◽  
The Impact

Africa continues to experience serious signs of multiple crises in the context of sustainability. These crises include vulnerability to climate change, rapid urbanization, food insecurity, and many others. One crisis, that defines Africa today, is the unprecedented rapid urbanization which continues to pose a big challenge to the diminishing available resources, environmental quality and human well-being. Cities in Africa continue to experience a fast horizontal growth of settlements due to influx of people from rural areas who often settle in the economically lowest segments in urban areas. This horizontal rapid growth has eaten up land set for agriculture around cities and promoted the rapid growth of informal settlements exacerbating the impacts of climate change leading to a negative impact on agricultural production. Policies linking rapid urbanization and climate change with agricultural productivity are need. This paper explores and documents the impact of rapid urbanization on climate change policies and subsequent impact on agriculture in Africa.

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