Wind power in China is experiencing accelerating growth to meet the need for structural reform of the energy supply, however its impact on the ecological environment urgently needs to be taken into account. In this study, the impact of a wind farm in Gonghe County, Qinghai Province, China, on local land surface temperature (LST) was explored by removing the temporal background using year-by-year LST averaging and filtering the spatial background using pixel-by-pixel LST averaging based on Moderate Resolution Imaging Spectroradiometer (MODIS) and the European Centre for Medium-Range Weather Forecast's ERA5 data. The main findings are as follows: (1) From a long-term series perspective, the LST on the wind farm and the adjacent areas shows an increasing trend, reaching 0.060K/19a in spring; (2) the wind farm exerts a warming effect on the local LST, with a maximum of 7.04 K and a minimum of 1.63 K, and there is a significant spatial matching with the wind farm boundaries, which is more obvious in spring and winter, and less pronounced in summer and autumn; (3) the construction of wind farms also has a potential upward impact on the LST in the adjacent areas, especially in autumn and winter, and the warming effect gradually decreases with increasing distance; (4) the warming effect is most remarkable when the predominant wind directions of the upwind and downwind are close to consistent and the differences in wind volumes are significant. Research findings on the effect of wind farms on local LST are vitally important for strengthening the establishment of wind farms, site selection of wind farms, and the scientific and reasonable utilization of wind energy resources.
Abstract Analyze the changes in land use and the spatial evolution characteristics of ecological product value in Hebei Province, understand the driving factors that affect the value of ecological products, and aim to promote the sustainable use of land resources and promote local economic development. This paper investigated the changes in land use and landscape patterns in Hebei Province from 2010 to 2022, and used the improved equivalent factor to account for the value of ecological products, used the global Moran’s I index, Getis-Ord General G index, and Getis-OrdG* index to explore the characteristics of spatial and temporal changes in the value of ecosystem services in different districts and counties of the study area, and finally used a geoprobe to explore the influence factors of land use change on the spatial and temporal changes in the value of ecological products in Hebei Province. value of ecological products in Hebei Province. The following conclusions were drawn: (1) Land use in Hebei Province is dominated by farmland, forests, grasslands and impervious surfaces, accounting for about 95% of the area of Hebei Province. (2) From the accounting results, the value of ecological products in Hebei Province during the study period shows a trend of rising, then falling and then rapidly rising, with the value of ecological products in Hebei Province amounting to 256,640,551,000,000 Yuan in 2010, and 488,748,000,000 Yuan in 2022, with a rise of close to 47.4892%. In addition, the high-value area of ecological product value is concentrated in the northern part of Hebei Province, with the city of Chengde and Zhangjiakou as the main areas of the dam plateau, and the low-value area is concentrated in the plains of Hebei Province. Damshang Plateau area, mainly in Chengde City and Zhangjiakou City, and the low-value area is concentrated in the Hebei Plain area. (3) When exploring the factors influencing the spatial and temporal changes of ecological product values in Hebei Province due to land use changes, population density, slope and elevation with large q-values are the main factors influencing the ecological product values in Hebei Province. In addition, in terms of factor interactions, there are two types of two-factor enhancement and nonlinear enhancement in the interaction of factors influencing the high and low values of ecological products in Hebei Province as a result of land use change. From 2010 to 2022, the land use and landscape patterns in Hebei Province have changed significantly, and the value of ecological products has also changed continuously. It is necessary to put forward a strategy to improve the value of ecological products based on the change of land use in Hebei Province, to promote the transformation of the economic development in the direction of ecologically friendly and sustainable development, and to realize the benign cycle of economic growth and environmental protection.
Net surface shortwave radiation (NSSR) is a key parameter for the estimation of surface energy budget. This paper proposes a method to directly estimate the NSSR from simulated Chinese Gaofen-5 (GF-5) data without using any ancillary information. Firstly, the narrowband reflectances of visible/near infrared channels at the top of the atmosphere (TOA) were converted to the TOA broadband albedo. Secondly, by categorizing the land surface into three types, the NSSR was estimated under clear and cloudy skies separately based on the relationship between TOA broadband albedo and the Earth's surface absorbed shortwave radiation. The estimation error of the absorption coefficient for each land type is lower than 0.05. Finally, by employing a look-up-table acquired in the process of narrowband-to-broadband conversion, and the parameters in the NSSR estimation model for each land type, the performance of the proposed method was evaluated, where the root mean square errors (RMSEs) were 25.85 (13.97) W/m 2 , 20.39 (7.97) W/m 2 , and 40.54 (11.26) W/m 2 for land, ocean and snow/ice surfaces for clear (cloudy) skies, respectively.
Escalating urban issues in Beijing call for comprehensive exploration of urban construction land expansion towards the goal of carbon neutrality. Firstly, urban construction land in Beijing during the period 2005–2020 was accurately detected using Landsat images and impervious surface data, and then its expansion characteristics were revealed. Finally, the driving mechanism of urban construction land expansion was explored using geographically and temporally weighted regression from the input–output perspective. The results showed that the expansion speed and intensity of urban construction land in Beijing showed an overall tendency to slow down, and the center of urban expansion shifted to the new urban development zone and ecological function conservation zone. Urban construction land expansion in the central urban area was first scattered and then compact, while that in the new urban development zone and ecological function conservation zone primarily followed an outward pattern. The permanent population, per capita GDP, and per capita retail sales of social consumer goods were the primary driving factors of urban construction land expansion in Beijing, the impacts of which varied significantly among different districts of Beijing. All these results can provide a solid foundation for improving land use policies towards the goal of carbon neutrality in highly urbanized areas.
Abstract Investigating the response of land surface energy exchange to key climatic signals such as the East Asian summer monsoon (EASM) is essential for understanding the intensive interactions in the Earth system. This study focuses on the summer monsoon transition zone (SMTZ) in China, which has a climate rather sensitive to the EASM activity, and examined the response of land surface energy exchange over the SMTZ to summer monsoon activity. A flux evaluation of five reanalysis/modeling data sets indicates that JRA-55(the Japane 55-year Reanalysis) reasonably represents interannual variations of surface heat fluxes over the SMTZ. The EASM activity is accurately identified in the SMTZ by introducing a monsoon temporal duration index (MTDI), which presents climate variations of summer rainfall and EASM activity better than commonly used summer monsoon indexes. Based on MTDI and long-term flux data sets, it was found that the interannual fluctuation of the EASM intensively controls surface energy partitioning and turbulent heat exchange but has a weak impact on radiative processes over the SMTZ. Furthermore, surface sensible and latent heat fluxes significantly responded to the influential period of the summer monsoon, exhibiting approximately quadratic/logarithmic relationships with the MTDI. More prominent interannual variabilities of turbulent heat fluxes were observed in weak summer monsoon years, during which an active interaction between surface energy exchange and a warming and drying climate occurred. An ensemble empirical mode decomposition (EEMD) analysis confirms that EASM activity dominates the quasi-biennial and multidecadal variations of turbulent heat fluxes over the SMTZ, which may be achieved by the transport of tropical quasi-biennial and Pacific Decadal Oscillation (PDO) signals to the mid-latitudes of East Asia. The expected intensification of summer monsoon activity in the future may induce acceleration of energy and hydrological cycle and exert a substantial impact on the availability of water and the ecosystem stability over the SMTZ.
Sensor-observed energy from adjacent pixels, known as the adjacency effect, influences land surface reflectivity retrieval accuracy in optical remote sensing. As the spatial resolution of thermal infrared (TIR) images increases, the adjacency effect may influence land surface temperature (LST) retrieval accuracy in TIR remote sensing. However, to our knowledge, few studies have focused on quantifying this adjacency effect on TIR measurements. In this study, a forward adjacency effect radiative transfer model (FAERTM) was developed to quantify the adjacency effect on high-spatial-resolution TIR measurements. The model was verified to be in good agreement with moderate resolution atmospheric transmission (MODTRAN) code, with a discrepancy <; 0.15 K. The adjacency effect on target pixel observations was found to be negligible beyond 3 km from the line of sight. Variations in aerosol type only slightly influenced adjacency effect magnitude. However, the adjacency effect quickly increased with increasing image spatial resolution, adjacent pixel temperature, and aerosol density. According to simulation results, the adjacency effect can be > 3 K in some cases. These findings indicate that the adjacency effect should be considered when retrieving LSTs from TIR measurements, at least in some specific conditions. The proposed FAERTM provides a useful model for quantifying and addressing the adjacency effect on TIR measurements.
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