库尔勒近地面CO2浓度空间分布及影响因素分析

Spatial Distribution and Influencing Factors of Near-surface CO Concentration in Korla

准确认知城市近地面CO2浓度分布与城市发展格局的相互关系,对城市的生态环境保护具有重要意义。文章以库尔勒城区为研究对象,以城市主干道为研究路线,用Li-6400开路式红外CO2分析器进行移动监测,采集2018年春季近地面CO2浓度数据,在明确库尔勒市近地面CO2浓度的空间分布格局的基础上,结合Landsat 8 OLI数据提取城市下垫面特征信息,分析土地利用类型对近地面CO2浓度的影响。结果表明:(1)库尔勒市近地面CO2浓度为(442.4±31.3)μmol/mol,分布呈现老城区>南市区>开发区的特点,城市中心CO2浓度较外缘高32.4%(193μmol/mol),形成明显的"CO2"岛。市中心CO2浓度与距市中心距离显著相关,相关性r=-0.86(P<0.01),距市中心距离每增加1 km,CO2浓度降低5.87μmol/mol。(2)近地面CO2浓度与风速呈显著负相关,相关系数为-0.215(P<0.05),与湿度、大气压强与近地面CO2浓度呈显著正相关,相关系数分别为0.23(P<0.01)、0.207(P<0.05)。(3)城市不透水层覆盖率与近地面CO2相关性为0.706(P<0.01),两者呈现显著正相关;绿地覆盖率与近地面CO2相关性次之,为0.599(P<0.01),二者呈负相关。可见,城市下垫面性质及气候因子对近地面CO2浓度影响显著,下垫面不透水层与绿地覆盖率对近地面CO2起到显著的指示作用。

Accurately recognizing the correlation between the distribution of near-surface CO2 concentration in the city and the urban development pattern is of great significance to the urban ecological environment protection.Taking the urban area of Korla as the research object and the main road of the city as the research route,the Li-6400 open-circuit infrared CO2 analyzer was used for mobile monitoring,and the data of near-surface CO2 concentration in the spring of 2018 was collected to determine the spatial distribution of near-surface CO2 concentration in Korla City.Based on the pattern,combined with Landsat 8 OLI data to extract the characteristics of the underlying surface of the City,the impact of land use types on the near-surface CO2 concentration was analyzed.The results show that the near-surface CO2 concentration in Korla is(442.4±31.3)μmol/mol,and the distribution of near-surface CO2 presents the characteristics of the Old City>South City>Development Zone.CO2 concentration in the city center is 32.4%(193μmol/mol)higher than the outer edge of the city,forming an obvious urban"CO2"island,and the CO2 concentration in the city center is significantly correlated with the distance from the city center,with the correlation r as-0.86(P<0.01),and the CO2 concentration decreases by 5.87μmol/mol for every 1 km increase from the city center.Near-surface CO2 concentration wind is significantly negatively correlated with velocity,the correlation coefficient is-0.215(P<0.05),and humidity,atmospheric pressure is significantly positively correlated with near-surface CO2 concentration,the correlation coefficients are 0.23(P<0.01),0.207(P<0.05).The correlation between the coverage of impermeable layer and CO2 near the ground is 0.706(P<0.01),and there is a significant positive correlation between the two.The correlation between green space coverage and near-surface CO2 is next,0.599(P<0.01),the two are negatively correlated.Therefore,the properties of urban underlying surface and climate factors have a significant effect on the concentration of near-surface CO2,and the coverage of impervious layer and green space on near-surface CO2 plays a significant role.