A Numeric Study of Regional Climate Change Induced by Urban Expansion in the Pearl River Delta, China

Wang, Xuemei; Liao, Junjie; Zhang, Jian; Shen, Chong; Chen, Weihua; Xia, Beicheng; Wang, Tijian

doi:10.1175/jamc-d-13-054.1

Cited by 107 publications

(77 citation statements)

References 50 publications

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“…Compared with suburban regions, the increase in surface roughness induced by urban expansion can cause a 50% wind speed decrease in the YRDR, China. Similar results were also reported by Wang et al (2013), who used the same model in the same region and found that the building-induced friction leads to decreases in the SWS. The SWS over urban areas has decreased by approximately 1.2-1.5 m s −1 in the YRDR, and these values are similar to the results of Zha et al (2017a).…”

Section: The Advantages and Disadvantages Of Different Methodssupporting

confidence: 88%

Changes in terrestrial near-surface wind speed and their possible causes: an overview

et al. 2017

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drag forces are caused by changes in the external and internal friction in the atmosphere. Changes in surface friction are mainly caused by changes in the surface roughness due to land use and cover change (LUCC), including urbanization, and changes in internal friction are mainly induced by changes in the boundary layer characteristics. Future studies should compare the spatio-temporal differences in SWS between high and low altitudes and quantify the effects of different factors on the SWS. Additionally, in-depth analysis of extreme SWS events and prediction of future mean and extreme SWS values at global and regional scales are also necessary. Abstract Changes in terrestrial near-surface wind speed (SWS) are induced by a combination of anthropogenic activities and natural climate changes. Thus, the study of the long-term changes of SWS and their causes is very important for recognizing the effects of these processes. Although the slowdown in SWS has been analyzed in previous studies, to the best of knowledge, no overall comparison or detailed examination of this research has been performed. Similarly, the causes of the decreases in SWS and the best directions of future research have not been discussed in depth. Therefore, we analyzed a series of studies reporting SWS trends spanning the last 30 years from around the world. The changes in SWS differ among different regions. The most significant decreases have occurred in Central Asia and North America, with mean linear trends of − 0.11 m s −1 decade −1 ; the second most significant decreases have occurred in Europe, East Asia, and South Asia, with mean linear trends of − 0.08 m s −1 decade −1 ; and the weakest decrease has occurred in Australia. Although the SWS in Africa has decreased, this region lacks long-term observational data. Therefore, the uncertainties in the long-term SWS trend are higher in this region than in other regions. The changes in SWS, caused by a mixture of global-, regional-, and localscale factors, are mainly due to changes in driving forces and drag forces. The changes in the driving forces are caused by changes in atmospheric circulation, and the changes in the Keywords

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Section: The Advantages and Disadvantages Of Different Methodssupporting

confidence: 88%

Changes in terrestrial near-surface wind speed and their possible causes: an overview

et al. 2017

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“…As reported in many previous studies, spatiotemporal urban land cover change is a serious concern both in megacities, such as Beijing [8,9], Shanghai [10][11][12], Hangzhou [13,14], and Guangzhou [15,16], and in developed coastal urban agglomerations, especially the three largest urban agglomerations, i.e., the Yangtze River Delta (YRD) [17,18], the Pearl River Delta (PRD) [19,20] and the Jing-Jin-Ji (JJJ) [21][22][23]. However, urban expansion in less developed cities and urban agglomerations has received little attention even though rapid urbanization has also occurred in these areas.…”

Section: Introductionmentioning

confidence: 89%

“…Numerous previous researches have shown that rapid urban expansion have occurred in the above three urban agglomerations over time [17,20,22,23], however, less for the MYRB urban agglomeration. To better understand the urban expansion in the MYRB urban agglomeration and the differences between the four national level urban agglomerations, a comparison of urban expansion rate among the four urban agglomerations was made.…”

Section: Urban Expansion In the Myrb Urban Agglomeration Compared Witmentioning

confidence: 99%

Satellite Monitoring of Urban Land Change in the Middle Yangtze River Basin Urban Agglomeration, China between 2000 and 2016

Liu

Chen

2017

Remote Sensing

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Detailed studies on the spatiotemporal patterns of urban agglomeration in the Middle Yangtze River Basin (MYRB) are rare. This paper analyzed the spatiotemporal patterns of urbanization in the MYRB using multi-temporal remote sensing data circa 2000, 2008 and 2016 integrated with geographic information system (GIS) techniques and landscape analysis approaches. A multi-level analysis of the rate and intensity, type as well as the landscape changes of urban expansion at regional, prefectural and inner-city levels was performed. Results show that the MYRB experienced rapid urban expansion with an annual expansion rate of 3.199%, especially in the Chang-Zhu-Tan and Poyang Lake metropolitan areas. The small and medium cities presented faster urban expansion than the larger cities with annual growth rates three times the average level. Urban expansion within the three capital cities was further analyzed in detail. It is found that outlying expansion and edge-expansion were the dominant growth patterns at all the three levels. Although urbanization in the MYRB has a remarkable increase in the past sixteen years, its annual growth rate of urban land expansion has fallen behind the three other large urban agglomerations in China as a result. Finally, the spatial evolution of the socioeconomic structure of the MYRB was further explored. It indicated that urban land was distributed mainly along the "northwest-southeast" direction and that the economic spatial interactions among cities showed a pattern of "multi-polarization and fragmentation", which illustrates the weak radiative driving forces of the central cities. The MYRB urban agglomeration faces a great challenge to manage trades-offs between narrowing the intra-regional disparity and maintaining synergetic development among cities.

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“…Additionally, a Single Layer Urban Canopy Model (SLUCM) coupled to the Noah land surface model (Noah/LSM) is adopted for a better modeling of the urban effects. Following the work of Q. and Wang et al (2014), the default values for urban canopy parameters in SLUCM are substituted by the typical values in South (Schell et al, 2001) China. As shown in Table 2, the values for building height, roof width, road width, urban fraction and surface albedo are modified for the cities in and outside PRD.…”

Section: Wrf/chem and Its Configurationmentioning

confidence: 99%

Changes in regional meteorology induced by anthropogenic heat and their impacts on air quality in South China

et al. 2016

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Abstract. Anthropogenic heat (AH) emissions from human activities can change the urban circulation and thereby affect the air pollution in and around cities. Based on statistic data, the spatial distribution of AH flux in South China is estimated. With the aid of the Weather Research and Forecasting model coupled with Chemistry (WRF/Chem), in which the AH parameterization is developed to incorporate the gridded AH emissions with temporal variation, simulations for January and July in 2014 are performed over South China. By analyzing the differences between the simulations with and without adding AH, the impact of AH on regional meteorology and air quality is quantified. The results show that the regional annual mean AH fluxes over South China are only 0.87 W m −2 , but the values for the urban areas of the Pearl River Delta (PRD) region can be close to 60 W m −2 . These AH emissions can significantly change the urban heat island and urban-breeze circulations in big cities. In the PRD city cluster, 2 m air temperature rises by 1.1 • in January and over 0.5 • in July, the planetary boundary layer height (PBLH) increases by 120 m in January and 90 m in July, 10 m wind speed is intensified to over 0.35 m s −1 in January and 0.3 m s −1 in July, and accumulative precipitation is enhanced by 20-40 % in July. These changes in meteorological conditions can significantly impact the spatial and vertical distributions of air pollutants. Due to the increases in PBLH, surface wind speed and upward vertical movement, the concentrations of primary air pollutants decrease near the surface and increase in the upper levels. But the vertical changes in O 3 concentrations show the different patterns in different seasons. The surface O 3 concentrations in big cities increase with maximum values of over 2.5 ppb in January, while O 3 is reduced at the lower layers and increases at the upper layers above some megacities in July. This phenomenon can be attributed to the fact that chemical effects can play a significant role in O 3 changes over South China in winter, while the vertical movement can be the dominant effect in some big cities in summer. Adding the gridded AH emissions can better describe the heterogeneous impacts of AH on regional meteorology and air quality, suggesting that more studies on AH should be carried out in climate and air quality assessments.

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A Numeric Study of Regional Climate Change Induced by Urban Expansion in the Pearl River Delta, China

Cited by 107 publications

References 50 publications

Changes in terrestrial near-surface wind speed and their possible causes: an overview

Changes in terrestrial near-surface wind speed and their possible causes: an overview

Satellite Monitoring of Urban Land Change in the Middle Yangtze River Basin Urban Agglomeration, China between 2000 and 2016

Changes in regional meteorology induced by anthropogenic heat and their impacts on air quality in South China

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