scholarly journals The Influence of Urban Surface Expansion in China on Regional Climate

2017 ◽  
Vol 30 (3) ◽  
pp. 1061-1080 ◽  
Author(s):  
Deming Zhao ◽  
Jian Wu
Keyword(s):  
East Asia ◽  
Eastern China ◽  
Urban Land Use ◽  
Radiation Budget ◽  
Urban Surface ◽  
Eastern Coast ◽  
Total Cloud Amount ◽  
Surface Expansion ◽  
Urban Surface Expansion ◽  
The Impact

Abstract Incorporating satellite-based urban surface data for the 1980s, 1990s, 2000s, and 2010s in China, contributions to regional warming, and changes in the precipitation due to urban surface expansion were explored using the nested Fifth-generation Pennsylvania State University–NCAR Mesoscale Model version 3.7 (MM5V3.7) with urban effects considered. The impact on surface air temperature at 2 m (SAT) due to urban surface expansion between the 1980s and the 2010s revealed that annual urban-related warming was lower over East Asia (0.031°C) and China (0.075°C) but higher in eastern China (0.14°C), which experienced dramatic urbanization. Greater warming could be detected over urban surface areas in the three city clusters [Beijing–Tianjin–Hebei (BTH) and the Yangtze and Pearl River deltas (YRD and PRD, respectively)], which reached 1.06°, 0.84°, and 0.92°C, respectively. Urban-related warming was not limited to a single city or city clusters but extended over a SAT-increased belt that covered the eastern coast of China. Further analysis showed that urban-surface-expansion-induced changes in albedo and the total cloud amount contributed to the changes in the radiation budget, which resulted in strong surface radiative forcings in the urban surface (14.5, 11.2, and 11.7 W m−2 for BTH, YRD, and PRD, respectively). However, significant differences could be detected for the transition from nonurban to urban land use compared to those that were classified as urban in both time periods because of the varied albedo changes. The urbanization-related warming, especially in the city cluster areas, also had a further effect on the large-scale circulation and precipitation. The precipitation was weakened in northeastern and northern China but intensified in eastern and southern China, which resulted in the strengthened precipitation over China (0.016 mm day−1, 0.65%) and East Asia (0.011 mm day−1, 0.28%). Therefore, subregional characteristics with marked seasonal, interannual, and decadal variations were detected for the influence of the urban surface expansion.

scholarly journals Modelling Daily Mean Surface Air Temperature Calculated from Different Methods and Its Impact on Urban-Related Warming Evaluations over Guangzhou and Shenzhen Using the WRF Model

Atmosphere ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 48
Author(s):  
Deming Zhao ◽  
Jian Wu
Keyword(s):  
Air Temperature ◽  
Diurnal Cycle ◽  
Climate Model ◽  
Dynamical Downscaling ◽  
Spatial Scales ◽  
Wrf Model ◽  
Surface Air Temperature ◽  
Urban Surface ◽  
Surface Expansion ◽  
Urban Surface Expansion

The impacts of urban surface expansion, based on satellite-derived data displaying urban surface expansion in China at different spatial scales from 1980 to 2016, were investigated using nested dynamical downscaling methods with the Weather Research and Forecasting (WRF) regional climate model at a 3.3-km resolution over a city and city cluster scale. Urban-related warming, based on daily mean surface air temperature at 2 m (SAT), calculated from the averages of four time records each day (00, 06, 12, and 18 h UTC, T4) and averages of SAT maximum (Tmax) and minimum (Tmin) (Txn), was evaluated. Differences in urban-related warming contributions calculated using T4 and Txn were small, whereas annual mean SAT and trends calculated using Txn were respectively and significantly larger and smaller than those calculated using T4 over Guangzhou and Shenzhen, excluding the trends over middle-northern Shenzhen. The differences in annual mean SAT calculated using T4 and Txn are attributed to nonlinear or asymmetric variations with time for the diurnal cycle of SAT. Meanwhile, differences in trends between T4 and Txn are interpreted as a strong trend for Tmin and a weak one for Tmax, which mitigated the trend for Txn. The impacts on the evaluations of urban-related warming contributions calculated from different methods were the largest over the areas classified as urban surfaces in both time periods (U2U), especially during intense urban-surface-expansion periods between 2000 and 2016. The subregional performances in the changes in annual mean SAT, trends, and urban-related warming are attributed to urban-surface-expansion, which induced varied changes in the diurnal cycle due to asymmetric warming during the daytime and nighttime over different subregions.

Contribution of Urban Surface Expansion to Regional Warming in Beijing, China

2017 ◽  
Vol 56 (6) ◽  
pp. 1551-1559 ◽  
Author(s):  
Deming Zhao ◽  
Jian Wu
Keyword(s):  
Urban Areas ◽  
Dynamical Downscaling ◽  
Urban Surface ◽  
Anthropogenic Activity ◽  
Regional Warming ◽  
Considerable Uncertainty ◽  
Surface Areas ◽  
Surface Expansion ◽  
Urban Surface Expansion ◽  
Beijing China

AbstractThe contribution of urban surface expansion to regional warming as detected from meteorological observational station data may vary with considerable uncertainty because of the spatial heterogeneity of such data—a situation that promotes a requirement for numerical model-based investigations. Satellite-based images from 1980 to 2016 that have fine resolution over three city clusters and that display the urban surface expansion in China from rapid economic development and anthropogenic activity were used to perform 37-yr nested dynamical downscaling using the Weather Research and Forecasting (WRF) Model. The urban surface areas in Beijing, China, expressed marked expansion in the last 37 years. The contribution of urban surface expansion to regional warming was approximately 22% of the overall warming in Beijing and was stronger in the plains areas of Beijing (42%). The contributions to land-use grids that changed from nonurban (in 1980) to urban (in 2016; N2U) were much stronger than those to grids that were classified as urban in both time periods (U2U), which were closer to the values of urban areas (including N2U and U2U) because of the intense increase in urban surface areas. Urban-related warming expressed marked annual variation and was greater in the warm seasons and smaller in the cold seasons. The greater increase in surface air temperature (SAT) minimum and the weaker SAT maximum accounted for the decreased diurnal temperature range.

scholarly journals Modulated Responses of East Asian Winter Climate to Anthropogenic Aerosols by Urban Cover in Eastern China

Atmosphere ◽  
2021 ◽  
Vol 12 (4) ◽  
pp. 471
Author(s):  
Jiechun Deng ◽  
Leying Zhang ◽  
Jing Ma ◽  
Dorina Chyi
Keyword(s):  
East Asia ◽  
East Asian ◽  
Eastern China ◽  
Land Use Changes ◽  
Northern China ◽  
Urban Land Use ◽  
Anthropogenic Aerosols ◽  
Winter Climate ◽  
Climate Responses

The increasing anthropogenic aerosols (AAs) over East Asia have caused significant regional climate responses, but the role of urban land-use changes which occur simultaneously, in altering these AA-induced changes, is not well understood. Here, the modulation of the AAs’ effect on the East Asian winter (November–January) climate by the urban cover in eastern China was investigated using the Community Atmosphere Model version 5.1 coupled with the Community Land Model version 4. Results show that the winter sulfate aerosol burden is higher from central eastern China to southern Japan in the case with the presence of urban cover than in the case without it, resulting from urban-induced circulation changes. Such aerosol changes markedly increase the cloud fraction and precipitation over northern China and the adjacent ocean to the east, especially convection activities around southern Japan. This leads to a cooling effect near the surface over northern China and in the mid-upper troposphere to the east due to aerosol direct and indirect effects. The resulting circulation responses act to shift the mid-tropospheric East Asian trough southward and the upper-level East Asian westerly jet-stream as well, further supporting the surface changes. These winter climate responses to the urban-modulated aerosols can largely offset or even reverse those to the AAs forcing without the urban cover in the model, especially in northern East Asia. This study highlights the need to consider the modulating role of urban land-use changes in assessing the AAs’ climatic effect over East Asia and other regions.

THE IMPACT OF DIFFERENT URBAN LAND USE TYPES ON AIR POLLUTION IN THE MEGACITY OF SÃO PAULO

2020 ◽  
Vol 7 (1) ◽  
pp. 91
Author(s):  
Júlio Barboza Chiquetto ◽  
Maria Elisa Siqueira Silva ◽  
Rita Yuri Ynoue ◽  
Flávia Noronha Dutra Ribieiro ◽  
Débora Souza Alvim ◽  
...  
Keyword(s):  
Land Use ◽  
Air Pollution ◽  
Urban Land ◽  
Sao Paulo ◽  
Urban Land Use ◽  
São Paulo ◽  
Land Use Types ◽  
The Impact

A poluição do ar é influenciada por fatores naturais e antropogênicos. Quatro pontos de monitoramento (veicular, comercial, residencial e background urbano (BGU))da poluição do ar em São Paulo foram avaliados durante 16 anos, revelando diferenças significativas devidoao uso do solo em todas as escalas temporais. Na escala diurna, as concentrações de poluentes primários são duas vezes mais altas nos pontos veicular e residencial do que no ponto BGU, onde a concentração de ozonio (O3) é 50% mais alta. Na escala sazonal, as concentrações de monóxido de carbono(CO) variaram em 80% devido ao uso do solo, e 55% pela sazonalidade.As variações sazonais ede uso do solo exercem impactos similares nas concentrações de O3 e monóxido de nitrogênio (NO). Para o material particulado grosso (MP10) e o dióxido de nitrogênio(NO2), as variações sazonais são mais intensas do que as por uso do solo. Na série temporal de 16 anos, o ponto BGU apresentou correlações mais fortes e significativas entre a média mensal de ondas longas (ROL) e o O3 (0,48) e o MP10 (0,37), comparadas ao ponto veicular (0,33 e 0,22, respectivamente). Estes resultados confirmam que o uso do solo urbano tem um papel significativo na concentração de poluentes em todas as escalas de análise, embora a sua influência se torne menos pronunciada em escalas maiores, conforme a qualidade do ar transita de um sistema antropogênico para um sistema natural. Isto poderá auxiliar decisões sobre políticas públicas em megacidades envolvendo a modificação do uso do solo.

scholarly journals Does the Construction and Operation of High-Speed Rail Improve Urban Land Use Efficiency? Evidence from China

Land ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 303
Author(s):  
Xinhai Lu ◽  
Yifeng Tang ◽  
Shangan Ke
Keyword(s):  
Economic Growth ◽  
Land Use ◽  
High Speed ◽  
Urban Land ◽  
Urban Land Use ◽  
Western China ◽  
High Speed Rail ◽  
Land Use Efficiency ◽  
Use Efficiency ◽  
The Impact

The construction and operation of high-speed rail (HSR) has become an important policy for China to achieve efficiency and fairness and promote high-quality economic growth. HSR promotes the flow of production factors such as labor and capital and affects economic growth, and may further affect urban land use efficiency (ULUE). To explore the impact of HSR on ULUE, this paper uses panel data of 284 cities in China from 2005 to 2018, and constructs Propensity Score Matching-Differences in Differences model to evaluate the effect of HSR on ULUE. The result of entire China demonstrates that the HSR could significantly improves the ULUE. Meanwhile, this paper also considers the heterogeneity of results caused by geographic location, urban levels and scales. It demonstrates that the HSR has a significantly positive effect on ULUE of Eastern, Central China, and large-sized cities. However, in Western China, in medium-sized, and small-sized cities, the impact of HSR on ULUE is not significant. This paper concludes that construction and operation of HSR should be linked to urban development planning and land use planning. Meanwhile, the cities with different geographical locations and scales should take advantage of HSR to improve ULUE and promote urban coordinated development.

Detection of Russian Fires Using MOPITT and MODIS Data

2005 ◽  
Vol 277-279 ◽  
pp. 816-823
Author(s):  
Sang Hee Lee ◽  
Gi Hyuk Choi ◽  
Hyo Suk Lim ◽  
Joo Hee Lee ◽  
Kwon Ho Lee ◽  
...  
Keyword(s):  
East Asia ◽  
Forest Fires ◽  
Eastern China ◽  
Northeast Asia ◽  
Smoke Aerosol ◽  
Modis Data ◽  
Smoke Pollution ◽  
Moderate Resolution ◽  
Large Fires ◽  
Moderate Resolution Imaging Spectroradiometer

The great fires were detected through the Moderate Resolution Imaging Spectroradiometer (MODIS) observations over Northeast Asia. The large amount of smoke produced near Lake Baikal was transported to East Asia using high Aerosol Optical Thickness (AOT) as seen through the satellite images. The smoke pollution from the Russian forest fires would sometimes reach Korea through Mongolia and eastern China. In May 2003, a number of large fires blazed through eastern Russian, producing a thick, widespread pall of smoke over much of East Asia. This study focuses on the identification of the carbon monoxide (CO) for MOPITT released from MOPITT primarily into East Asia during the Russian Fires. In the wake of the fires, the 700hPa MOPITT retrieved CO concentrations which reached up to 250ppbv. Smoke aerosol retrieval using a separation technique was also applied to the MODIS data observed in 14-22 May 2003. Large AOT, 2.0 ~ 5.0, was observed over Korea on 20 May 2003 due to the influence of the long range transport of smoke aerosol plume from the Russian Fires.

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