Aircraft Measurements of the Radiative Effects of Tropospheric Aerosols: I. Observational Results of
Aircraft Measurements of the Radiative Effects of Tropospheric Aerosols: I. Observational Results of
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对流层气溶胶辐射效应的飞机测量：一、观测结果
DOI：
10.2151/jmsj1965.67.5_847
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发表时间：
1989
影响因子：
3.1
通讯作者：
M. Shiobara
中科院分区：
文献类型：
--
作者：
S. Asano;M. Shiobara
通过飞机测量气溶胶以及太阳和红外辐射通量，并结合同时进行的直接太阳光束地面光谱衰减测量，研究了对流层气溶胶对低层大气辐射收支的影响。本文详细分析了六个在无云的冬季正午太阳天顶角在60 °左右的观测实例。在这6起案件中，4起是在陆地（筑波）上进行的，2起是在沿海（鹿岛田）进行的。气溶胶浓度的垂直廓线与水汽的垂直廓线相关，气溶胶谱分布呈典型的双峰型。对流层气溶胶对太阳辐射有很强的散射和吸收作用，对太阳辐射的垂直分布有很大的影响。在对流层低层，平均气溶胶吸收效应被发现至少是相同的数量级，由于水蒸气。而在稠密的霾层中，瞬时太阳加热率高达5*/天，气溶胶的贡献约为水汽的3倍。由于红外辐射通量廓线主要取决于气体成分和温度的分布，对流层气溶胶的影响并不大。低对流层经历了1*/天的顺序的IR冷却，但在表面层的冷却减少时，表面温度比表面空气温度高得多。对流层气溶胶的存在对对流层低层-地面系统顶边界的辐射收支只有很小的影响。然而，对流层气溶胶极大地影响了太阳能在系统中的分布。与无气溶胶的情况相比，对流层下层由于气溶胶吸收而经历了大量的额外太阳能加热，其代价是由表面吸收的太阳能的相当数量（24小时平均值为10 W/m2）。由于太阳能加热与红外线冷却相结合，对流层下部有相当大的净加热，上部有净冷却。这一点以及地面的净太阳加热可能是筑波上空形成发达的混合层的原因。
Effects of tropospheric aerosols on the radiation budget in the lower atmosphere have been studied through aircraft measurements of aerosols and the solar and infrared radiative fluxes combined with a concurrent ground-based spectral attenuation measurement of the direct solar beam. Six cases of observations during cloudless winter midday hours with the solar zenith angles around 60*, were carefully analyzed. Of the six cases, four were made over land (Tsukuba) and two cases were conducted off the coast (Kashimanada). The vertical profiles of aerosol concentrations were associated with those of water vapor, and the aerosol size distributions were typically bi-modal. Tropospheric aerosols effectively scatter and absorb the solar radiation, greatly influencing the vertical profiles of the upward and downward solar fluxes. Over the lower troposphere, the average aerosol absorption effects were found to be at least the same order of magnitude as those due to water vapor. In dense haze layers, however, the instantaneous solar heating rate was as large as 5*/day, and the contribution from aerosols was about three times larger than that of water vapor. Since the IR flux profiles were mainly determined by the distribution of gaseous constituents and temperature, the effects of tropospheric aerosols were not appreciably large. The lower troposphere experienced IR cooling of the order of 1*/day, but the cooling was lessened in the surface layers when the surface temperature was much higher than the surface air temperature. Presence of the tropospheric aerosols had only a small effect on the radiation budget at the top boundary of the lower troposphere-surface system. However, the tropospheric aerosols greatly affected the distribution of solar energy in the system. Compared to an aerosol-free case, the lower troposphere experienced a substantial amount of additional solar heating due to aerosol absorption, at the expense of a comparable amount (of the order of 10W/m2 as the 24-hour mean) of the solar energy absorbed by the surface. As a consequence of the solar heating combined with the IR cooling, the lower troposphere has a substantial net heating in its lower part and a net cooling in its upper part. This, as well as the net solar heating of the surface may be responsible for the formation of the well-developed mixed layer over Tsukuba.