Urbanization Amplified Asymmetrical Changes of Rainfall and Exacerbated Drought: Analysis Over Five Urban Agglomerations in the Yangtze River Basin, China

Huang, Shuzhe; Gan, Yuan; Zhang, Xiang; Chen, Nengcheng; Wang, Chao; Gu, Xihui; Ma, Jianmin; Niyogi, Dev

doi:10.1029/2022ef003117

Cited by 35 publications

(29 citation statements)

References 97 publications

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“…6a). In pivotal biographical zones, such as China's Loess Plateau and the Qinling Mountains, the change in vegetation sensitivity was highly susceptible to the SPEI and VPD (Zhang et al, 2023). The growth rate of sensitivity increased with the slowing rate of VPD, implying that there will be a factorial ampli cation of the moisture effect on vegetation response mechanisms in the future, in accordance with the recent observed increase in the vegetation water constraint of vegetation growth (Jiao et al, 2021;Zhang et al, 2021).…”

Section: Increased Responses Of Ecosystems To Climate Change Over Timesupporting

confidence: 58%

Increasing sensitivity of the terrestrial ecosystem to climate change in China

Wei¹,

Zhang³

et al. 2023

Preprint

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Changes in heat and moisture significantly co-alter ecosystem functioning. However, knowledge on the dynamics of ecosystem responses to climate change is limited. Here, we quantify long-term ecosystem sensitivity (ES) based on weighted ratios of vegetation productivity variability and multiple climate variables from satellite observations, greater values of which indicate more yields per hydrothermal condition change. Our results show that ES exhibits large spatial variability and increases with the aridity index. A positive temporal trend of ES is found in 61.28% of the study area from 2001 to 2021, which is largely attributed to a declining vapor pressure deficit and constrained by solar radiation. Moreover, carbon dioxide plays a dual role; in moderation it promotes the fertilization effect, whereas in excess, it suppresses vegetation growth by triggering droughts. Our findings highlight that moisture stress between land and atmosphere is one of the key prerequisites for ecosystem stability, offsetting part of the negative effects of heat.

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Section: Increased Responses Of Ecosystems To Climate Change Over Timesupporting

confidence: 58%

Increasing sensitivity of the terrestrial ecosystem to climate change in China

Wei¹,

Zhang³

et al. 2023

Preprint

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“…Furthermore, highly reflective materials can reduce the moisture transported to the PBL, and subsequently, cities could be drier (Huang et al., 2023). In other words, GRs can append additional moisture to the PBL with extra latent heat flux and remove air pollutants through dry and wet depositions but entail a significant volume of water for regular irrigation to maintain cooling efficacy and plant activity, which is an added challenge for urban planners.…”

Section: Discussion: Limitations Impacts and Future Researchmentioning

confidence: 99%

Exploring the Meteorological Impacts of Surface and Rooftop Heat Mitigation Strategies Over a Tropical City

et al. 2023

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Different heat mitigation technologies have been developed to improve the thermal environment in cities. However, the regional impacts of such technologies, especially in the context of a tropical city, remain unclear. The deployment of heat mitigation technologies at city‐scale can change the radiation balance, advective flow, and energy balance between urban areas and the overlying atmosphere. We used the mesoscale Weather Research and Forecasting model coupled with a physically based single‐layer urban canopy model to assess the impacts of five different heat mitigation technologies on surface energy balance, standard surface meteorological fields, and planetary boundary layer (PBL) dynamics for premonsoon typical hot summer days over a tropical coastal city in the month of April in 2018, 2019, and 2020. Results indicate that the regional impacts of cool materials (CMs), super‐cool broadband radiative coolers, green roofs (GRs), vegetation fraction change, and a combination of CMs and GRs (i.e., “Cool city (CC)”) on the lower atmosphere are different at diurnal scale. Results showed that super‐cool materials have the maximum potential of ambient temperature reduction of 1.6°C during peak hour (14:00 LT) compared to other technologies in the study. During the daytime hours, the PBL height was considerably lower than the reference scenario with no implementation of strategies by 700 m for super‐cool materials and 500 m for both CMs and CC cases; however, the green roofing system underwent nominal changes over the urban area. During the nighttime hours, the PBL height increased by CMs and the CC strategies compared to the reference scenario, but minimal changes were evident for super‐cool materials. The changes of temperature on the vertical profile of the heat mitigation implemented city reveal a stable PBL over the urban domain and a reduction of the vertical mixing associated with a pollution dome. This would lead to crossover phenomena above the PBL due to the decrease in vertical wind speed. Therefore, assessing the coupled regional impact of urban heat mitigation over the lower atmosphere at city‐scale is urgent for sustainable urban planning.

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“…To meet the long-term span and effectively identify the vegetation within the city, we used the China land cover dataset (CLCD) with a 30 m spatial resolution from 1990 to 2021 to study rapid urban expansion in arid regions (https://zenodo.org/record/ 5816591) [38]. Compared to other products such as GLC_FCS30, Global30, and ESRI10, CLCD has a longer and more continuous time series [16,39]. The VG data were extracted from Landsat NDVI products in Google Earth Engine (https://earthengine.google.…”

Section: Datamentioning

confidence: 99%

“…Theil-Sen median estimator, as a non-parametric method, has been proved to be highly reliable in estimating changes over time [45]. Therefore, we used it to assess the intensity of trends in urban expansion and VG [16,46], and it can be calculated below:…”

Section: Theil-sen Median Estimatormentioning

confidence: 99%

“…Natural climate conditions such as precipitation will seriously restrict the phenological cycle and distribution pattern of vegetation, which is also more sensitive to the fluctuations of climate change in arid regions than in humid regions. In traditional thinking, urbanization directly encroaches upon a large area of vegetation and has a negative impact on the local ecological environment [3,4,15,16]. However, some studies have shown that with the gradual improvement in human maintenance and management, urbanization has a positive impact on urban vegetation [17][18][19].…”

Section: Introductionmentioning

confidence: 99%

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Positive impact of urbanization on vegetation growth has been continuously strengthening in arid regions of China

Li,

Cui,

Liu

et al. 2023

Environ. Res. Lett.

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The ecological environment is fragile in arid regions, and the direct and indirect impacts of continuing urbanization on vegetation growth in cities still need to be studied in depth. In this study, we focused on four provincial capital cities (Urumqi, Lanzhou, Yinchuan, and Hohhot) in arid regions of China. We used continuous 30 m land cover and vegetation greenness (VG) data from 1990 to 2021 to extract the impact of urbanization on vegetation growth by separating the impact of natural conditions. Our results showed that the study area’s urban area (UA) had expanded rapidly at a rate of 39.2 km2/a, increasing by 3.39 times between 1990 and 2021. While urban expansion occurred rapidly, the overall VG of the study area also increased (slope = 2.16 × 10−3), with the enhancement of VG increasing gradually from west to east. The VG and its trend in the UA were significantly higher than those in the natural vegetation area (NA). In addition, the duration of the urban vegetation growth season was longer than that of the NA, which also confirmed the positive impact of urbanization on the vegetation growth period. Furthermore, we found that the positive impact of urbanization on vegetation had continuously strengthened over time. In 1990 and 2021, the VG areas had 83% and 87% above the ‘zero-impact line’ in the UA, respectively, indicating a very significant impact of urbanization on vegetation growth in arid regions with fragile natural conditions. Our study identified the long-term dynamic trends in urbanization and VG in arid regions and clarified the non-linear relationship between the two concurrent growth factors. This has significant implications for correctly understanding the impact of urbanization on vegetation in arid regions and can provide a scientific reference for the ecological construction of urban environments in the region.

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Urbanization Amplified Asymmetrical Changes of Rainfall and Exacerbated Drought: Analysis Over Five Urban Agglomerations in the Yangtze River Basin, China

Cited by 35 publications

References 97 publications

Increasing sensitivity of the terrestrial ecosystem to climate change in China

Increasing sensitivity of the terrestrial ecosystem to climate change in China

Exploring the Meteorological Impacts of Surface and Rooftop Heat Mitigation Strategies Over a Tropical City

Positive impact of urbanization on vegetation growth has been continuously strengthening in arid regions of China

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