Indian Ocean Experiment: An integrated analysis of the climate forcing and effects of the great Indo-Asian haze
Indian Ocean Experiment: An integrated analysis of the climate forcing and effects of the great Indo-Asian haze
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DOI：
10.1029/2001jd900133
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发表时间：
2001-11-27
影响因子：
4.4
通讯作者：
Valero, FPJ
中科院分区：
文献类型：
--
作者：
Ramanathan, V;Crutzen, PJ;Valero, FPJ
每年从12月到4月，人为的雾霾都会蔓延到北印度洋的大部分地区，以及南亚和东南亚。印度洋实验（INDOEX）记录了从单个颗粒到其对区域气候强迫的贡献的尺度上的印亚雾霾。本研究集成了多平台。利用一维和四维模式进行观测（卫星、飞机、船舶、地面站和气球），以推导由直接、半直接和两种间接效应引起的区域气溶胶强迫。雾霾颗粒由几种无机和含碳物质组成，包括吸收黑碳团簇、粉煤灰和矿物粉尘。最引人注目的结果是南亚大部分地区和北印度洋的大量气溶胶。1999年1月至3月的可见光深度在大部分大陆地区约为0.5，在赤道印度洋由于远距离传输而达到0.2。气溶胶层延伸至3公里的高度。黑碳对细颗粒质量的贡献为14%，对可见光深度的贡献为11%。用几种独立的方法估计的单散射反照率在内陆和公海上始终在0.9左右。人为源对气溶胶载荷和光学深度的贡献高达80%（+/- 10%）。现场资料清楚地支持第一种间接效应的存在（增加的气溶胶浓度产生更多的云滴，有效半径更小），用于制定复合间接效应方案。印亚气溶胶通过一系列复杂的加热（正强迫）和冷却（负强迫）过程影响辐射强迫。云层和黑碳成为主要的参与者。然而，主要因素是地表较大的负强迫（-20 +/- 4 W m(-2)）和较大的大气加热。从区域上看，吸收霾减少了相当于海洋总热通量50%的地表太阳辐射，并使对流层下层的太阳加热增加了近一倍。我们用一般环流模型证明了这种额外的加热如何显著扰乱热带降雨模式和水文循环，并对全球气候产生影响。
Every year, from December to April, anthropogenic haze spreads over most of the North Indian Ocean, and South and Southeast Asia. The Indian Ocean Experiment (INDOEX) documented this Indo-Asian haze at scales ranging from individual particles to its contribution to the regional climate forcing. This study integrates the multiplatform. observations (satellites, aircraft, ships, surface stations, and balloons) with one- and four-dimensional models to derive the regional aerosol forcing resulting from the direct, the semidirect and the two indirect effects. The haze particles consisted of several inorganic and carbonaceous species, including absorbing black carbon clusters, fly ash, and mineral dust. The most striking result was the large loading of aerosols over most of the South Asian region and the North Indian Ocean. The January to March 1999 visible optical depths were about 0.5 over most of the continent and reached values as large as 0.2 over the equatorial Indian ocean due to long-range transport. The aerosol layer extended as high as 3 km. Black carbon contributed about 14% to the fine particle mass and 11% to the visible optical depth. The single-scattering albedo estimated by several independent methods was consistently around 0.9 both inland and over the open ocean. Anthropogenic sources contributed as much as 80% (+/- 10%) to the aerosol loading and the optical depth. The in situ data, which clearly support the existence of the first indirect effect (increased aerosol concentration producing more cloud drops with smaller effective radii), are used to develop a composite indirect effect scheme. The Indo-Asian aerosols impact the radiative forcing through a complex set of heating (positive forcing) and cooling (negative forcing) processes. Clouds and black carbon emerge as the ma or players. The dominant factor, however, is the large negative forcing (-20 +/- 4 W m(-2)) at the surface and the comparably large atmospheric heating. Regionally, the absorbing haze decreased the surface solar radiation by an amount comparable to 50% of the total ocean heat flux and nearly doubled the lower tropospheric solar heating. We demonstrate with a general circulation model how this additional heating significantly perturbs the tropical rainfall patterns and the hydrological cycle with implications to global climate.