AEROSOL ABSORPTION-MEASUREMENTS AT BARROW, MAUNA-LOA AND THE SOUTH-POLE
AEROSOL ABSORPTION-MEASUREMENTS AT BARROW, MAUNA-LOA AND THE SOUTH-POLE
复制标题
DOI：
10.1029/95jd00513
复制
发表时间：
1995-05-20
影响因子：
4.4
通讯作者：
BODHAINE, BA
中科院分区：
文献类型：
--
作者：
BODHAINE, BA
1986年至今，在阿拉斯加州巴罗（Barrow）使用气压计连续测量了气溶胶吸收（sigma(sp)）；莫纳罗亚，夏威夷（1990年至今）；南极，南极洲（1987-1990）。这三个台站是由美国国家海洋和大气管理局（NOAA）气候监测和诊断实验室（CMDL）运营的基线监测站网络的一部分。这些站点也连续多年测量了凝结核（CN）浓度和多波长气溶胶散射（sigma(sp)）。使用制造商建议的校准，通常根据大气黑碳气溶胶（BC）浓度报告大气浓度计的测量结果。在这里，我们通过假设气压计过滤器上的气溶胶吸收比大气中的气溶胶吸收增强1.9倍，从气压计测量中推断出原位西格玛（ap） （550 nm）。这与使用19 m(2) g（-1）作为酒精计过滤器上BC的比吸收和10 m(2) g（-1）用于大气中BC的原位比吸收（两者比吸收的比率为1.9）是一致的。虽然这些比吸收值在不同的环境中可能有很大的不同，但比率可能是相对恒定的。单散射反照率定义为ω = sigma(sp)/(sigma(sp) + sigma(ap))，由同时测量的sigma（ap）和sigma（sp）估算。此外，假设sigma（ap）的依赖关系为1/ λ，在450至700 nm波长区域，多波长sigma（sp）测量允许估计omega的波长依赖关系。每个站点在sigma(ap), sigma（sp）和omega上显示出相当大的年周期。巴罗年周期的最大值主要是由春季北极雾霾现象引起的；冒纳罗亚年循环中的最大值是由春季亚洲沙尘输送引起的；南极年周期的最大值是由中纬度南部的冬末输送引起的。发现巴罗的年平均值为sigma(ap) - 4.1 x 10(-7) m(-1)（接近41 ng m(-3) BC）和omega = 0.96；sigma(ap) = 5.8 x 10(-8) m(-1)（接近5.8 ng m(-3) BC）， ω = 0.97；sigma(ap) = 6.5 x 10(-9) m(-1)（接近0.65 ng m(-3) BC）和omega = 0.97南极。还发现omega的波长依赖性在巴罗和南极可能很重要，但在莫纳罗亚不重要。
Aerosol absorption (sigma(sp)) has been measured continuously using aethalometers at Barrow, Alaska (1986 to present); Mauna Loa, Hawaii (1990 to present); and south pole, Antarctica (1987-1990). These three stations are part of a network of baseline monitoring stations operated by the Climate Monitoring and Diagnostics Laboratory (CMDL) of the National Oceanic and Atmospheric Administration (NOAA). Condensation nucleus (CN) concentration and multiwavelength aerosol scattering (sigma(sp)) have also been measured continuously for many years at these stations. Aethalometer measurements are usually reported in terms of atmospheric black carbon aerosol (BC) concentration using the calibration suggested by the manufacturer. Here we deduce the in situ sigma(ap) (550 nm) from aethalometer measurements by assuming that the aerosol absorption on the aethalometer filter is enhanced by a factor of 1.9 over that in the atmosphere. This is consistent with using 19 m(2) g(-1) for the specific absorption of BC on the aethalometer filter and 10 m(2) g(-1) for the in situ specific absorption of BC in the atmosphere (the ratio of the two specific absorptions is 1.9). Although these values of specific absorption may vary significantly for different environments, the ratio might be expected to be relatively constant. The single-scattering albedo, defined by omega = sigma(sp)/(sigma(sp) + sigma(ap)), has been estimated from the simultaneous measurements of sigma(ap) and sigma(sp). Furthermore, assuming a 1/lambda dependence for sigma(ap), in the 450 to 700-nm wavelength region, multiwavelength sigma(sp) measurements allow the estimation of the wavelength dependence of omega. Each station shows a considerable annual cycle in sigma(ap), sigma(sp), and omega. The maximum in the Barrow annual cycle is caused primarily by the springtime Arctic haze phenomenon; the maximum in the Mauna Loa annual cycle is caused by the springtime Asian dust transport; and the maximum in the south pole annual cycle is caused by late winter transport from southern midlatitudes. It was found that annual mean values are sigma(ap) - 4.1 x 10(-7) m(-1) (approximate to 41 ng m(-3) BC) and omega = 0.96 for Barrow; sigma(ap) = 5.8 x 10(-8) m(-1) (approximate to 5.8 ng m(-3) BC) and omega = 0.97 for Manua Loa; and sigma(ap) = 6.5 x 10(-9) m(-1) (approximate to 0.65 ng m(-3) BC) and omega = 0.97 for south pole. It was also found that the wavelength dependence of omega may be important at Barrow and south pole, but not important at Mauna Loa.