It is important to quantify changes in CO2 sources and sinks with land use and land cover change. In the last several decades, carbon sources and sinks in East Asia have been altered by intensive land cover changes due to rapid economic growth and related urbanization. To understand impact of urbanization on carbon cycle in the monsoon Asia, we analyze net CO2 exchanges for various land cover types across an urbanization gradient in Korea covering high-rise high-density residential, suburban, cropland, and subtropical forest areas. Our analysis demonstrates that the urban residential and suburban areas are constant CO2 sources throughout the year (2.75 and 1.02 kg C m−2 year−1 at the urban and suburban sites), and the net CO2 emission indicate impacts of urban vegetation that responds to the seasonal progression of the monsoon. However, the total random uncertainties of measurement are much larger in the urban and suburban areas than at the nonurban sites, which can make it challenging to obtain accurate urban flux measurements. The cropland and forest sites are strong carbon sinks because of a double-cropping system and favorable climate conditions during the study period, respectively (− 0.73 and − 0.60 kg C m−2 year−1 at the cropland and forest sites, respectively). The urban area of high population density (15,000 persons km−2) shows a relatively weak CO2 emission rate per capita (0.7 t CO2 year−1 person−1), especially in winter because of a district heating system and smaller traffic volume. The suburban area shows larger net CO2 emissions per capita (4.9 t CO2 year−1 person−1) because of a high traffic volume, despite a smaller building fraction and population density (770 persons km−2). We show that in situ flux observation is challenging because of its larger random uncertainty and this larger uncertainty should be carefully considered in urban studies. Our findings indicate the important role of urban vegetation in the carbon balance and its interaction with the monsoon activity in East Asia. Urban planning in the monsoon Asia must consider interaction on change in the monsoon activity and urban structure and function for sustainable city in a changing climate.

中文翻译：

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基于涡度协方差测量的韩国城市化梯度范围内的净二氧化碳交换量的比较评估。

量化随土地利用和土地覆被变化而产生的二氧化碳源和汇的变化非常重要。在过去的几十年中，由于经济的快速增长和相关的城市化进程，土地覆盖率发生了巨大变化，东亚的碳源和碳汇已经发生了变化。为了了解城市化对季风亚洲的碳循环的影响，我们分析了韩国城市化梯度范围内各种土地覆盖类型的净二氧化碳交换量，其中包括高层高密度住宅区，郊区，农田和亚热带森林地区。我们的分析表明，城市居民区和郊区是全年不变的CO2排放源（在城市和郊区，2.75和1.02 kg C m-2 year-1），并且净CO2排放表明城市植被的影响季风的季节变化。然而，与非城市站点相比，城市和郊区的测量总不确定性要大得多，这可能使获取准确的城市通量测量值具有挑战性。在研究期间，农田和森林场所是双碳作物系统和有利的气候条件，因此是强大的碳汇（农田和森林场所分别为− 0.73和− 0.60 kg C m-2 year-1）。高人口密度（15,000人km-2）的城市地区人均二氧化碳排放量相对较弱（0.7吨二氧化碳当年-1人-1），特别是在冬季，这是由于区域供热系统和交通流量较小。郊区由于人流量大，人均净二氧化碳排放量更高（4.9吨二氧化碳当年-1人-1），尽管建筑面积和人口密度较小（770人km-2）。我们表明，原位通量观测具有挑战性，因为它具有较大的随机不确定性，并且在城市研究中应仔细考虑较大的不确定性。我们的发现表明，城市植被在碳平衡中的重要作用及其与东亚季风活动的相互作用。季风亚洲的城市规划必须考虑到季风活动的变化以及城市结构和功能在气候变化中的可持续发展的相互作用。我们的发现表明，城市植被在碳平衡中的重要作用及其与东亚季风活动的相互作用。季风亚洲的城市规划必须考虑到季风活动的变化以及城市结构和功能在气候变化中的可持续发展的相互作用。我们的发现表明，城市植被在碳平衡中的重要作用及其与东亚季风活动的相互作用。季风亚洲的城市规划必须考虑季风活动的变化以及城市结构和功能的相互作用，以在气候变化的情况下实现可持续城市发展。