重庆土地利用结构低碳优化及其风热环境变化
Effects of Land Use optimization on carbon emissions and wind-thermal environments in Chongqing
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摘要: 建设低碳、宜居新型城市是城市发展的新理念新趋势,在城市规划建设中同步考虑低碳排放和气候适应性改善,对降低城镇化进程中的气候变化影响、提高城市生活品质具有重要意义。本文以重庆经济技术开发区为试验区,基于线性规划对试验区2025年规划土地利用结构进行低碳优化,通过微尺度数值模式模拟土地利用低碳优化+空间优化后试验区1月、7月风热环境的变化。结果表明:(1)土地利用结构低碳优化后,试验区减少了建设用地等土地碳源,增加了林地、草地等碳汇,年土地碳排放总量减少19.0×104t,降低了12.1%。(2)低碳优化+空间优化改善了试验区通风环境,1月、7月平均风速分别增加0.8%、1.7%,局地最大增幅8.0%、11.0%;61.1%、74.4%的地段平均风速增加;日逐小时序列中分别有12个时次、18个时次平均风速增加。(3)优化后试验区城市热岛趋于缓解,1月、7月平均气温分别下降1.3%、0.7%,局地最大降幅12.9%、5.0%;61.2%、57.7%的地段平均气温下降;日逐小时序列中所有时次平均气温都有所下降。对城市土地利用结构进行低碳优化和空间优化在一定程度上能够同时降低碳排放、改善风热环境、提高城市气候适应性,其模拟评估结果可以为制定定量化经济社会发展规划相关目标和城市总体规划相关指标提供参考。Abstract: Constructing low-carbon and livable new cities is a new concept and trend in urban development. Considering simultaneously low-carbon emissions and climate adaptability improvements in urban planning and construction holds paramount significance. This approach plays a critical role in mitigating the effects of climate change throughout the urbanization process and enhancing the overall quality of urban life. This study selected the Chongqing Economic and Technological Development Zone as the experimental area, employing linear programming to conduct low-carbon optimization on the planned land use structure for the year 2025. Utilizing a micro-scale numerical model, the changes in wind-thermal environment were simulated within the experimental area for both January and July following the optimization of land use for low-carbon and spatial efficiency. The results indicate that the following: (1) After optimizing the land use structure for low-carbon, the experimental area reduced carbon sources such as construction land while increasing carbon sinks like forests and grasslands. The total annual land carbon emissions decreased by 19.0×104 tons, a reduction of 12.1%. (2) The combination of low-carbon optimization and spatial optimization improved the ventilation environment in the experimental area. In January and July, the average wind speeds increased by 0.8% and 1.7%, respectively, with local maximum increases of 8.0% and 11.0%. Average wind speeds increased at 61.1% and 74.4% of the locations, and an observed increase in average wind speed occurred at 12 time points and 18 time points in the daily hourly sequence, respectively. (3) After optimization, the urban heat island effect in the experimental area tended to alleviate. The average temperatures in January and July showed reductions of 1.3% and 0.7%, respectively, with maximum localized decreases of 12.9% and 5.0%. Average temperatures decreased at 61.2% and 57.7% of the locations, and all time points in the daily hourly sequence showed a decrease in average temperature. Optimizing urban land use structure for both low-carbon and spatial efficiency holds the potential to concurrently reduce carbon emissions, improve wind-thermal environment, and enhance urban climate adaptability. The results of simulation evaluations can serve as valuable references for establishing quantitative objectives in economic and social development planning, and informing key indicators for comprehensive urban planning.