ACE-1 - Southern Hemisphere marine aerosol characterisation experiment

Metadata record for data from ASAC Project 829See the link below for public details on this project.From the abstract of one of the referenced papers:During the intensive field operations period (November 15 to December 14, 1995) of the First Aerosol Characterisation Experiment (ACE 1) cold front activity was generally above average, resulting in below average temperatures, pressures, and rainfall. The principal cause was the presence for much of the experiment of a long wave trough. This trough was mobile, traversing the ACE area during the project, with some warm anomalies evident in teh areas under the influence of the long wave ridges. There is evidence of greater convective activity than normal, possibly leading to a slightly deeper than average mixing layer. A greater west to northwesterly component to the air flow than average during November appears to have led to higher than average concentrations of radon and particles in the clean, marine or 'baseline'; sector at Cape Grim (190 degrees to 280 degrees). This is likely to have resulted from inclusion of continental air from western parts of the Australian mainland in the baseline sector winds. Although aerosol-bound sulfur species were generally near their normal concentrations across the ACE 1 area, the overall pattern including atmospheric dimethylsulfide suggest slightly higher than usual sulfur species levels in the southern part of the region and lower concentrations in the northern part during November. This could be related to changes in marine biogenic productivity, air-sea exchange, or atmospheric removal. In December, the changing long wave pattern brought an increase in south and southwesterly flow over the entire region. The baseline sector became less affected by continental species, but it appears that the colder conditions brought by this pattern have led to lower than usual atmospheric concentrations of biogenic species, as the region went into one of the coldest summers on record.

本数据集为ASAC项目829（ASAC Project 829）的相关数据元记录，有关该项目的公开详情请参阅下方链接。以下引自所引用论文之一的摘要：在1995年11月15日至12月14日的第一次气溶胶表征实验（First Aerosol Characterisation Experiment，ACE 1）密集野外作业期间，冷锋活动整体高于平均水平，导致气温、气压与降雨量均低于平均值。本次实验多数时段的主要影响因素为长波槽活动。该长波槽具有移动性，在项目实施期间贯穿ACE实验区域；受长波脊影响的区域则出现了明显的暖异常现象。有观测证据表明，对流活动较常年更为活跃，这可能使得混合层厚度略高于平均水平。11月期间，气流的西至西北向分量较常年偏高，致使格雷姆角（Cape Grim）190°至280°的洁净海洋"基准"区域内，氡气与颗粒物浓度均高于平均值。该现象大概率是由于基准区域的气流裹挟了澳大利亚大陆西部的大陆性空气所导致的。尽管ACE 1实验区域内的气溶胶结合态硫物种整体浓度接近常年水平，但结合大气中二甲基硫（dimethylsulfide）的整体分布模式来看，11月该区域南部的硫物种浓度略高于常年，北部则低于常年。这一分布差异可能与海洋生源生产力、海气交换过程或大气清除机制的变化有关。12月，长波环流格局发生变化，使得整个区域的南风与西南风气流占比上升。基准区域受大陆性物种的影响有所减弱，但由于该区域迎来了有记录以来最寒冷的夏季之一，此次环流变化带来的低温天气使得大气中的生源性物种浓度较常年偏低。