Temporal variations of atmospheric carbon dioxide in the southernmost part of Japan
Temporal variations of atmospheric carbon dioxide in the southernmost part of Japan
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DOI：
10.1111/j.1600-0889.2007.00288.x
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发表时间：
2007-01
期刊：
影响因子：
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通讯作者：
Xia Zhang;T. Nakazawa;M. Ishizawa;S. Aoki;S. Nakaoka;S. Sugawara;Shamil Maksyutov;T. Saeki;T. Hayasaka
中科院分区：
文献类型：
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作者：
Xia Zhang;T. Nakazawa;M. Ishizawa;S. Aoki;S. Nakaoka;S. Sugawara;Shamil Maksyutov;T. Saeki;T. Hayasaka
本文对1993年6月至2005年4月期间在日本石垣岛和初间岛之间的渡轮上获得的东亚亚热带地区大气CO2的时间变化进行了分析。年平均二氧化碳浓度从1994年的360.1 ppmv增加到2004年的378.4 ppmv，年均增长率为1.8 ppmv。生长速率呈现年际变化，在ingenso事件期间具有较高的值。平均季节CO2循环在4月初达到最大值，在9月中旬达到最小值，峰间振幅为8.5 ppmv。利用三维大气输送模式进行的数值模拟显示CO2增长率的年际变化与观测值相似，但季节周期的振幅更大，最大浓度比观测值早1个月出现。1998年春季观测到的低CO2值可能与1997/1998年ENSO事件有关。逆向轨迹分析表明，它们是由于大气输送的变化，即来自太平洋的海洋气团压倒了来自亚洲大陆的污染气团。偶尔也会观测到二氧化碳的极端值（或高或低）。利用大气输送模式计算的CO2浓度场与空气包裹的反向轨迹的比较表明，这些异常的CO2浓度是由空气输送造成的，不仅受人为CO2排放的影响，而且主要受中国陆地生物圈活动的影响。
We present analysis of the temporal variation of atmospheric CO2 in the subtropical region of East Asia, obtained aboard a ferry between Ishigaki Island and Hateruma Island, Japan for the period June 1993–April 2005. The annual mean CO2 concentration increases from 360.1 ppmv in 1994 to 378.4 ppmv in 2004, showing an average growth rate of 1.8 ppmv yr-1. The growth rate shows interannual variations with high values duringENSOevents. The average seasonal CO2 cycle reaches the maximum in early April and the minimum in mid-September, with a peak-to-peak amplitude of 8.5 ppmv. Numerical simulations using a three-dimensional atmospheric transport model show interannual variations of the CO2 growth rate similar to the observation, but the amplitude of the seasonal cycle is larger, with maximum concentration appearing earlier than the observation by 1 month. Low CO2 values observed during the spring of 1998 are likely associated with the 1997/1998 ENSO event. A backward trajectory analysis suggests that they were due to changes in atmospheric transport whereby maritime air masses from the Pacific Ocean dominated over polluted air masses from the Asian Continent. Extreme values (either high or low) of CO2 are also occasionally observed. A comparison of backward trajectories of air parcels with CO2 concentration fields calculated using the atmospheric transport model shows that these unusual CO2 concentrations result from the transport of air affected not only by anthropogenic CO2 emissions but also by terrestrial biospheric activities mainly in China.