Seasonal measurements of nonmethane hydrocarbons and carbon monoxide at the Mauna Loa Observatory during the Mauna Loa Observatory Photochemistry Experiment 2
Seasonal measurements of nonmethane hydrocarbons and carbon monoxide at the Mauna Loa Observatory during the Mauna Loa Observatory Photochemistry Experiment 2
复制标题
冒纳罗亚天文台光化学实验 2 期间非甲烷碳氢化合物和一氧化碳的季节性测量
DOI：
10.1029/95jd01543
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发表时间：
1996
影响因子：
--
通讯作者：
P. Zimmerman
中科院分区：
文献类型：
--
作者：
J. Greenberg;D. Helmig;P. Zimmerman
1991 年 9 月至 1992 年 8 月，在莫纳罗亚天文台对一氧化碳和非甲烷碳氢化合物进行了现场测量。观察到 CO 和大多数 NMHC 的浓度存在明显的季节性周期，1 月至 4 月的平均浓度较高，5 月中旬至 10 月的平均浓度低得多。 CO 和 NMHC 的来源似乎随季节变化，并且在冬季（城市/工业）和春季（未确定）显得更加均匀。夏威夷周围的海洋似乎不是二氧化碳和大多数 NMHC 的主要来源，而是乙烷和丙烯的主要来源。乙烯和丙烯始终存在于自由对流层空气采样中，表明自由对流层和海洋边界层之间每天都存在交换。在自由对流层流动期间到达 MLO 的空气具有季节性相似的光化学年龄（大约 20 天），并且在至少 10 天内没有显着的 NMHC 新鲜源输入（乙烯和丙烯除外）。春季大气稀释过程对大气浓度的影响最弱，而化学损失过程的影响最大。春季期间进行的飞机测量在趋势和绝对浓度方面与 MLO 进行的地面测量一致。海拔范围内 NMHC 浓度的时间趋势相似。这些趋势随海拔高度的变化而变化，并表征了具有不同化学成分的分层大气。大多数样品中检测到丙酮和甲基乙基酮。还检测到 N-烷基醛，但可能是采样过程中收集的有机气溶胶形成的假象。
Measurements of carbon monoxide and nonmethane hydrocarbons were made in situ at the Mauna Loa Observatory from September 1991 through August 1992. A distinct seasonal cycle in concentrations was observed for CO and most NMHCs, with higher average concentrations from January through April and much lower average concentrations from mid-May through October. The sources of CO and NMHCs appeared to vary with season and appeared more homogeneous in winter (urban/industrial) and spring (unidentified). The ocean around Hawaii did not appear to be a major source of CO and most NMHCs, but was the major source of ethane and propene. Ethene and propene were always present in free tropospheric air sampled, indicating daily exchange between the free troposphere and the marine boundary layer. Air arriving at MLO during free tropospheric flow periods had seasonally similar photochemical age (approximately 20 days), with no significant fresh source inputs of NMHCs (except ethene and propene) within at least 10 days. The influence of atmospheric dilution processes on atmospheric concentrations was weakest in the spring period, when the influence of chemical loss processes was greatest. Aircraft measurements made during the spring agreed in trends and absolute concentrations with ground-based measurement made at MLO. The temporal trends in concentrations of NMHCs within altitude ranges were similar. These trends varied with altitude and characterized a layered atmosphere with differing chemical composition. Acetone and methyl ethyl ketone were detected in most samples. N-alkyl aldehydes were also detected but may be artifacts formed from organic aerosols collected in the sampling process.