摘要:
为研究广西壮族自治区防城港市2001—2015年间热岛效应的时空变化规律,利用遥感监测防城港市15 a来城市热岛效应的演变特征.选用2001年、2008年和2015年获取的3期陆地卫星(Landsat5 TM和Landsat8 OLI)遥感数据,反演防城港市地表温度(land surface temperature,LST);设置热岛强度及热岛比例指数2个评价指标,从热岛强度的时空分布和面积变化、城市热岛比例指数发展特征以及城市下垫面特性对热岛效应的影响3个方面分析防城港市热岛效应15 a间的演变特征.研究结果表明:①防城港市各区市县建成区面积均呈迅速扩张的趋势;②城市热岛强度逐年增强,港口区强热岛区增幅最快,年均增长率达到26.72%; ③城市热岛比例指数逐年递增,东兴市最高,达到0.62;④城市绿地和水体对城市热岛效应具有明显的降温作用,水体的作用距离和降温幅度均大于绿地,但防城港市建成区植被和水体的比例明显偏低.上述研究成果可为防城港市创建全国园林城市提供科学合理的建议.
Abstract:
To study the spatio-temporal variation of urban heat island effects in Fangchenggang City from 2001 to 2015,the authors used the remote sensing methods to monitor the variation characteristics of urban heat island effects in Fangchenggang City for a period of 15 years. The land surface temperature(LST)was retrieved using remote sensing images(Landsat5 TM and Landsat8 OLI) acquired in three periods of 2001,2008 and 2015. Then, both urban heat island intensity and urban -heat -island ratio index were constructed to analyze the evolution characteristics of heat island effect in the past 15 years from three aspects: the space-time distribution and area variation of heat island intensity, the development characteristics of urban - heat - island ratio index and the influence of underlying surface condition on heat island effect. Some conclusions have been reached:①Urban area exhibits a trend of rapid expansion in the study area. ② The urban heat island intensity increases year by year, especially in Gangkou District,where annual growth rate reaches 26.72%. ③The urban-heat-island ratio index is rising year by year in all districts,among which,Dongxing reaches the highest value of 0.62. ④Cooling effects are obviously for both urban green space and water body,but the operating distance and cooling amplitude of water body are larger than those of green space. However,the proportion of urban vegetation and water of the study area is markedly low. The research results may provide scientific and reasonable proposals for Fangchenggang government's aim of reaching the goal of creating a national garden city.
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