WRF/Chem modeling of the impacts of urban expansion on regional climate and air pollutants in Yangtze River Delta, China

Transboundary environmental problems caused by urban expansion and economic growth cannot be solved by individual cities. Successful intercity environmental cooperation relies on the clear identification and definition of the rights and obligations of each city. An Ecosystem services (ES) approach not only budgets the ES supply and demand of a city, but also defines the spatial relationships between Services Provisioning Areas (SPA) and Services Benefiting Areas (SBA). However, to date, quantitative studies integrating ES budgets and spatial relations have been scarce. This study integrates ecosystem services supply–demand budgeting with flow direction analysis to identify intercity environmental cooperation in the highly urbanized Yangtze River Delta (YRD) region of China for water-related ecosystem services (flood protection, erosion regulation and water purification). The results demonstrated that there were significant spatial mismatches in the supply and demand of three water-related ES among 16 core cities in the YRD region: five to six cities in the southern part of the region had significant service surpluses, while ten to 11 cities in the north–central part had significant service deficits. We then went on to offer definitions for Ecosystem Services Surplus City, Ecosystem Services Deficit City and Ecosystem Services Balance City, as well as Service Provisioning City, Service Benefiting City and Service Connecting City in which to categorize cities in the YRD Region. Furthermore, we identified two intercity cooperation types and two non-cooperation types. This framework can be used to promote ecological integration in highly urbanized regions to advance sustainable development.

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Urban dry island effect and its potential underlying mechanisms in the Yangtze River Delta urban agglomeration, China

10.5194/egusphere-egu2020-2162 ◽

2020 ◽

Author(s):

Baoni Li

Keyword(s):

Yangtze River ◽

Regional Climate ◽

Yangtze River Delta ◽

Urban Land ◽

River Delta ◽

Urban Agglomeration ◽

The Yangtze River ◽

Atmospheric Humidity ◽

Urban Land Expansion ◽

The Yangtze River Delta

<p>Land use/cover change (LUCC) affects regional climate change not only through its direct changes of land surface properties, but also through its further modifications of land-atmosphere interactions including the surface energy budget, water cycle and carbon cycle. Urban land expansion as a typical case of LUCC, has been widely discussed about its effects on regional climate, notably on temperature and known for urban heat island (UHI). Another important climate variable atmospheric humidity is also seriously affected by LUCC but has not earned as much attention as temperature. We examined atmospheric humidity changes by a series of indicators in the Yangtze River Delta urban agglomeration of China during 1965-2017, and found obvious urban dry land (UDI) effect in the urban cores, as characterized by decreased humidity and increased vapor pressure deficit. Furthermore, we found similar spatial patterns of humidity changes with urban land expansion process and strong correlations of humidity changes with evapotranspiration and leaf area index changes, indicating that LUCC affects regional climate through an ecohydrological way. We suggest that the UDI effect should be paid more attention in future urban planning and landscape design and more quantitative estimations of urban expansion effect on regional and global drying trends are needed.</p>

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Regional Characteristics of Air Pollutants during Heavy Haze Events in the Yangtze River Delta, China

Aerosol and Air Quality Research ◽

10.4209/aaqr.2015.09.0551 ◽

2016 ◽

Vol 16 (9) ◽

pp. 2159-2171 ◽

Cited By ~ 9

Author(s):

Honglei Wang ◽

Bin Zhu ◽

Lijuan Shen ◽

Honghui Xu ◽

Junlin An ◽

...

Keyword(s):

Air Pollutants ◽

Yangtze River ◽

Yangtze River Delta ◽

River Delta ◽

The Yangtze River ◽

Regional Characteristics ◽

The Yangtze River Delta

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Impact of COVID-19 Lockdown on Air Pollutants in a Coastal Area of the Yangtze River Delta, China, Measured by a Low-Cost Sensor Package

Atmosphere ◽

10.3390/atmos12030345 ◽

2021 ◽

Vol 12 (3) ◽

pp. 345

Author(s):

Lang Chen ◽

Jingjing Li ◽

Xiaobing Pang ◽

Kangli Shi ◽

Jianmeng Chen ◽

...

Keyword(s):

Air Pollutants ◽

Yangtze River ◽

Low Cost ◽

Yangtze River Delta ◽

River Delta ◽

The Yangtze River ◽

Coastal City ◽

Sensor Package ◽

The Impact ◽

The Yangtze River Delta

Ningbo is a major coastal city in the Yangtze River Delta region, China, with the largest cargo capacity in the world. We conducted a field campaign in Ningbo to measure the impact of the COVID-19 lockdown on air pollutants including NO2, O3 and CO from 21 January to 23 March 2020, using a home-made low-cost sensor package. The average concentrations of NO2, O3 and CO were observed to be 7.2, 37.5 and 648.5 ppb, respectively, during the lockdown. Compared with the previous year, the concentrations of NO2 and CO decreased by 63.1% and 6.9%, while the concentration of O3 increased by 37.9%. The significant reduction of NO2 concentration may be attributed to the reduced emissions of freighters and heavy trucks with lower port cargo throughput, which led to a decrease of NO concentration. The increase of O3 concentration was probably due to the lower titration of O3 by NO. After the lockdown, the concentrations of O3 and NO2 increased by 15.5% and 143.1%, respectively, compared with those during the lockdown. The temporal variations of the concentrations of NO2, O3 and CO measured by the sensor package were coincident with those obtained by the reference apparatus, which proves the sensor package to be suitable for air quality monitoring in field campaigns. This is the first time that a dramatic decrease in NO2 concentration in a coastal city due to a lockdown has been reported.

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The study of emission inventory on anthropogenic air pollutants and VOC species in the Yangtze River Delta region, China

Atmospheric Chemistry and Physics Discussions ◽

10.5194/acpd-11-951-2011 ◽

2011 ◽

Vol 11 (1) ◽

pp. 951-983 ◽

Cited By ~ 6

Author(s):

C. Huang ◽

C. H. Chen ◽

L. Li ◽

Z. Cheng ◽

H. L. Wang ◽

...

Keyword(s):

Air Pollutants ◽

Yangtze River ◽

Emission Inventory ◽

Yangtze River Delta ◽

River Delta ◽

The Yangtze River ◽

Voc Emissions ◽

Anthropogenic Air Pollutants ◽

The Yrd ◽

The Yangtze River Delta

Abstract. The purpose of this study is to develop an emission inventory for major anthropogenic air pollutants and VOC species in the Yangtze River Delta (YRD) region for the year 2007. A "bottom-up" methodology was adopted to compile the inventory based on major emission sources in the sixteen cities of this region. Results show that the emissions of SO2, NOx, CO, PM10, PM2.5, VOCs, and NH3 in the YRD region for the year 2007 are 2391.8 kt, 2292.9 kt, 6697.1 kt, 3115.7 kt, 1510.8 kt, 2767.4 kt, and 458.9 kt, respectively. Ethylene, mp-xylene, o-xylene, toluene, and 1,2,4-trimethylbenzene, 2,4-dimethylpentane, ethyl benzene, propylene, 1-pentene, and isoprene are the key species contributing 77% to the total OFPs. The spatial distribution of the emissions shows the emissions and OFPs are mainly concentrated in the urban and industrial areas along the Yangtze River and around the Hangzhou Bay. The industrial sources including power plant, other fuel combustion facilities, and non-combustion processes contribute about 97%, 86%, 89%, 91%, and 69% of the total SO2, NOx, PM10, PM2.5, and VOC emissions. Vehicles take up 12.3% and 12.4% of the NOx and VOC emissions, respectively. Regarding OFPs, chemical industry, domestic use of paint and printing, and gasoline vehicle contribute 38.2%, 23.9%, and 11.6% to the ozone formation in the YRD region.

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Spatiotemporal Characterization of the Urban Expansion Patterns in the Yangtze River Delta Region

Remote Sensing ◽

10.3390/rs13214484 ◽

2021 ◽

Vol 13 (21) ◽

pp. 4484

Author(s):

Ziqi Yu ◽

Longqian Chen ◽

Long Li ◽

Ting Zhang ◽

Lina Yuan ◽

...

Keyword(s):

Yangtze River ◽

Urban Expansion ◽

Yangtze River Delta ◽

River Delta ◽

Urban Agglomeration ◽

The Yangtze River ◽

Delta Region ◽

Gravity Center ◽

Yangtze River Delta Region ◽

The Yangtze River Delta

Characterizing urban expansion patterns is of great significance to planning and decision-making for urban agglomeration development. This study examined the urban expansion in the entire Yangtze River Delta Region (YRDR) with its land-use data of six years (1995, 2000, 2005, 2010, 2015, and 2018). On the basis of traditional methods, we comprehensively considered the four aspects of urban agglomeration: expansion speed, expansion difference, expansion direction, and landscape pattern, as well as the interconnection of and difference in the expansion process between each city. The spatiotemporal heterogeneity of urban expansion development in this region was investigated by using the speed and differentiation indices of urban expansion, gravity center migration, landscape indices, and spatial autocorrelations. The results show that: (1) over the 23 years, the expansion of built-up land in the Yangtze River Delta Region was significant, (2) the rapidly expanding cities were mainly located along the Yangtze River and coastal areas, while the slowly expanding cities were mainly located in the inland areas, (3) the expansion direction of each city varied and the gravity center of the urban agglomeration moved toward the southwest, and (4) the spatial structure of the region became more clustered, the shape of built-up land turned simpler, and fragmentation decreased. This study unravels the spatiotemporal change of urban expansion patterns in this large urban agglomeration, and more importantly, can serve as a guide for formulating urban agglomeration development plans.

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