东亚地区云和地表反照率对硫酸盐直接辐射强迫的影响

文中利用区域气候模式深入探讨了东亚地区云及地表反照率对硫酸盐直接辐射强迫的影响 ,同时定量估算了东亚地区云区气溶胶的直接辐射强迫 ,讨论了硫酸盐对地表和大气短波辐射平衡产生的不同影响。研究表明 :云对气溶胶的直接辐射强迫具有很强的减弱作用 ,这种减弱作用不仅取决于云覆盖份数 ,而且取决于云的光学厚度。就区域平均而言 ,文中模拟的东亚地区气溶胶直接辐射强迫为 - 0 .0 97W /m2 ,占总直接辐射强迫的 10 .4%左右。表明云对硫酸盐直接辐射具有很强的减弱作用 ,在估算其总的直接辐射强迫时 ,云区的贡献不可忽视。较高的地表反照率会减弱硫酸盐的直接辐射强迫 ,而较低地表反照率则会增加硫酸盐的辐射强迫。硫酸盐气溶胶对大气辐射平衡影响非常小 ,但对地表辐射平衡产生重要影响 ,影响程度与大气几乎一致。

EFFECT OF CLOUD AND SURFACE ALBEDO ON DIRECT SULFATE RADIATIVE FORCING OVER EAST ASIA

A regional climate model is used to investigate the effect of clouds and surface albedo on direct sulfate radiative forcing over East Asia. The annual direct radiative forcing (DRF) from cloud regions is estimated. In the final, the effects of sulfate upon the surface and atmospheric solar radiation budget are also discussed respectively. The simulated results indicated that the effect of cloud upon the DRF of sulfate is generally to weaken the forcing, this weakening depends on cloud cover and cloud optical depth. The annual cloudy-sky DRF is approximately -0.097 W/m2 for our simulated domain, and the contribution to the total DRF from cloud-sky regions is approximately 10.4 %. It means that the DRF from cloud-sky regions can not be negligible in spite of cloud strongly weakening the DRF of sulfate aerosol. High surface reflectance tends to enhance the DRF of sulfate, while low surface reflectance tends to weaken the DRF of sulfate. The effect of sulfate on atmospheric radiation balance is very small.However, sulfate aerosol leads to a reduction in the surface solar irradiance and the reduction is very similar in magnitude and spatial distribution to the solar radiative forcing at the top of the model.