沙尘和人为气溶胶的直接辐射效应对亚洲气候的影响

发布时间：2017-12-27 13:25

本文关键词：沙尘和人为气溶胶的直接辐射效应对亚洲气候的影响　出处：《南京信息工程大学》2015年硕士论文　论文类型：学位论文

【摘要】：本文使用耦合了化学过程的区域气候模式RegCM4.0,对沙尘和三种人为气溶胶的直接辐射效应对亚洲气候的影响进行了研究。对于东亚地区和南亚地区,地表和大气层顶的短波、长波和总辐射强迫的符号基本一致,只是地表的短波、长波和总辐射强迫比对应的大气层顶辐射强迫强度大一些。对于大气层顶和地表,气溶胶主要通过产生负的短波辐射强迫而产生负的总辐射强迫,而对长波辐射强迫的影响相对较小。对于东亚地区,冬季光学厚度与夏季相当,夏季大气层顶总辐射强迫强度绝对值比冬季略大,夏季地表总辐射强迫强度绝对值比冬季大得多。对于南亚地区,夏季气溶胶光学厚度比冬季大得多；夏季的大气层顶和地表总辐射强迫绝对值远大于冬季。对于东亚,在冬季,由于48°N以南的低层有较强的降温,而高层气温有较弱的升温,使稳定度增加,并且48°N以南的上空基本为下沉运动,从而使得48°N以南的冬季降水减少。对于夏季,2°N到14°N、14°N到16°N、16°N到25°N、25°N到40°N的上升、下沉、上升、下沉运动分别增强,从而导致了2°N到14°N、14°N到16°N、16°N到25°N、25°N到40°N的夏季降水的增加、减少、增加、减少。气溶胶使东亚冬季风增强。气溶胶使东亚热带夏季风和25°N以北的东亚副热带夏季风分别增强、减弱,这与沙尘和人为气溶胶引起的地表气压变化有关。在冬季和夏季,沙尘和人为气溶胶都使总降水减少,夏季总降水减少幅度比冬季大。在冬季,沙尘和人为气溶胶主要影响层云降水,使层云降水减少,而对积云降水几乎没有影响,夏季与之相反,气溶胶主要影响积云降水,使积云降水减少而对层云降水影响较小。对于南亚,在冬季,气溶胶使6°N到16°N和19°N到26°N上空的上升运动增强,从而造成这些区域总降水的增强,气溶胶对27°N到32°N上空的垂直运动影响较小,但是低层降温,高层升温,大气稳定度增加,从而使该区域总降水减少；对于夏季,气溶胶使5。N到16。N、17.5。N到190N和28。N到32。N上空的上升运动增强,从而造成这些区域总降水的增强,气溶胶使20。N到28。N上空的下沉运动增强,低层降温,高层升温,大气稳定度增加,从而使该区域总降水减少。对于南亚冬季,印度南部的以东和以西海域的地表气压有微弱的降低,从而造成降压区的南侧会产生偏西风,从而使南亚冬季风减弱；对于夏季,气溶胶使东阿拉伯海的地表气压降低,气溶胶使印度东北部、不丹和孟加拉国的地表气压降低,上述降压区的南侧会产生偏西风,从而使南亚夏季风增强。对于冬季,气溶胶使层云降水、对流降水分别增加、减少,但层云降水增加的幅度比对流降水减少的幅度大一些,最终造成总降水有微弱的增加；对于夏季,气溶胶主要是通过使对流降水减少,从而使总降水减少。
[Abstract]:In this paper, we use the regional climate model RegCM4.0 coupled with chemical process to study the direct radiation effects of dust and three kinds of artificial aerosols on Asian climate. For East Asia and South Asia, the signs of shortwave, longwave and total radiation forcing are basically the same. Only the short wave, long wave and total radiation forcing on the surface are stronger than the corresponding upper atmosphere radiative forcing. For the top of the atmosphere and the earth's surface, aerosols mainly produce negative total radiation forcing through negative short wave radiation forcing, but have little influence on longwave radiation forcing. For East Asia, the optical thickness in winter is similar to that in summer. The absolute value of the total atmospheric radiation intensity at the top of the atmosphere is slightly larger than that in winter, and the absolute value of the total surface radiation forcing in summer is much larger than that in winter. In South Asia, the optical thickness of aerosol in summer is much larger than that in winter, and the absolute value of the atmospheric top and surface total radiation in summer is far greater than that in winter. For East Asia, in the winter, because of the low temperature in the south of the 48 degree N, there is a strong cooling, while the upper air temperature has a weaker temperature, which makes the stability increase. And the 48 degree N is basically sinking down to the south, so that the winter rainfall in the south of 48 degrees N decreases. For the summer, 2 ~ N to 14 ~ N, 14 ~ N to 16 ~ N, 16 ~ N to 25 ~ N, 25 ~ N to 40 ~ N rising and sinking, rising and sinking motion were enhanced, resulting in 2 ~ N to 14 ~ N, 14 ~ N to 16 ~ N 16 ~ N to 25 ~ N, 25 ~ N to increase, summer precipitation of 40 DEG N reduction, increase, reduction. The East Asian winter monsoon is enhanced by aerosols. The East Asian summer monsoon and the East Asian subtropical summer monsoon in the north of 25 N are enhanced or weakened by aerosols, which is related to the change of surface pressure caused by dust and anthropogenic aerosols. In winter and summer, both sand dust and anthropogenic aerosol reduce the total precipitation, and the decrease of total precipitation in summer is larger than that in winter. In the winter, dust and anthropogenic aerosols mainly affect the stratiform precipitation, the stratiform precipitation is reduced, but has almost no effect on cumulus precipitation, summer on the contrary, the main effect of aerosol cumulus precipitation, the cumulus precipitation decrease but little influence on stratiform precipitation. In South Asia, in the winter, the aerosol 6 DEG N to 16 DEG N and 19 DEG N to 26 DEG N ascending motion over the increase, resulting in the enhancement of the total precipitation, aerosol to 27 DEG N to 32 DEG N vertical movement influence over smaller, but lower temperature, high temperature, atmospheric stability the degree of increase, so that the total precipitation in summer 5, aerosol. N to 16. N, 17.5. N to 190N and 28. N to 32. The rising movement over N increases the total precipitation in these areas, and aerosols make 20. N to 28. The subsidence of the N is enhanced, the lower layer cooling, the high rise and the increase of the atmospheric stability, thus reducing the total precipitation in the region. For the South Asian winter, sea surface pressure in southern India in the East and the West have weak decreased, resulting in blood pressure will produce area south westerly, so that the South Asian Winter Monsoon weakened; for the summer, aerosol reduces the surface pressure of East Arabia sea, aerosol decreased in Northeast India, Bhutan and Bangladesh surface pressure the buck, area south westerly winds will produce, so that the South Asian summer monsoon enhanced. In winter, the stratiform precipitation and aerosol convective precipitation were increased and decreased, but the increase is less than the stratiform precipitation convective precipitation rate is larger, resulting in a weak increase in total precipitation; for the summer, aerosol was reduced by making the convective precipitation, so that the total precipitation reduced.
【学位授予单位】：南京信息工程大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：X513;P461

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