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The iron hypothesis, first proposed by John Martin in 1990[1], suggests that some surface oceans such as North and Equatorial Pacific Oceans have high nutrient but low chlorophyll (HNLC). Thus iron coming from terrestrial dusts is the primary factor limit…  相似文献   
3.
京津地区沙尘暴与盐碱尘暴浅析   总被引:1,自引:0,他引:1  
韩同林 《科学》2008,60(1):46-49
对于京津地区的广大百姓而言,沙尘暴是再熟悉不过,但对尘暴和盐碱尘暴,则可能甚感生疏和不解.这是由于自20世纪晚期以来,被众多专家和媒体传播得最广的沙尘暴,但在最近几年的研究中却发现不完全是沙尘暴,而是尘暴,并且还是带有极大危害的盐碱尘暴.  相似文献   
4.
尘暴之忧 2007年6月,地面上的天文学家们观测到一场正在发展中的火星尘暴,而此时的"勇气号"和"机遇号"火星探测器已经在火星上工作近三年半了.科学家担心这次尘暴会影响这两个探测器在火星上的正常工作,他们甚至担心强大的风力会把探测器吹跑.这种担心并非没有道理,现在我们知道,至少"机遇号"遇到了麻烦,它的太阳能电池板积了厚厚的火星灰,这些灰尘挡住了2/3的入射阳光,使部分阳光无法转化成电能,机遇号因此变得有些步履蹒跚了.  相似文献   
5.
《科学之友》2008,(3):12
众所周知,尘暴覆盖了火星表面,然而最新的观测发现,火星上空由干冰形成的云雾非常浓厚,甚至在这颗红色行星表面投下明显的阴影。  相似文献   
6.
The Ebinur Lake region was described as a "Green Labyrinth" in "Xinjiang Map Records: Records of Rivers" published in 1910, however, the ecology and environment in the region have been seriously degenerated due to the impacts of human activities during the recent 40 years. A dried-up lake basin with an area of 107.4 km^2 forms in its northwestern part, is covered by unconsolidated silt deposit without vegetation, and has become one of the main dust sources of dust weathers in north Xinjiang, and the dust with an annual amount of 4.8×10^6 t is blown out of the region by strong winds from the Alataw mountain-gap where there are 164 days occurring strong winds in a year. The rational water area and inflow of the Ebinur Lake for improving the ecology in the lake region and effectively controlling wind erosion in the dried-up lake basin are estimated using the water balance equation after analyzing the current ecological problems and the relationship between the granular composition of deposit in the dried-up lake basin and the dust weathers, and the ecological effects in recent years are monitored. It is considered that the water area of the Ebinur Lake for improving the ecology in the lake region and effectively controlling wind erosion in the dried-up lake basin should be 800 km^2at least, and the annual volume of surface runoff and groundwater recharging the lake should be over 7.92×10^8 m^3.  相似文献   
7.
我国的沙暴、尘暴及其防治   总被引:1,自引:0,他引:1  
我国是沙尘暴易发的国家 ,进入90年代以来 ,沙尘暴有频率增加、强度加大、范围扩展、危害程度加剧的趋势。据统计 ,我国发生强沙尘暴的次数 ,50年代为5次 ,60年代为8次 ,70年代为13次 ,80年代为14次[1] ,90年代为23次[2] ,呈明显上升趋势。沙尘暴的强度及造成的损失 ,以90年代最为突出 ,发生于1993年5月5日(5.5沙尘暴)和1998年4月16日(4.16沙尘暴)的特大强沙尘暴 ,是我国近100年来所罕见 ,损失极其惨重。5、5沙尘暴锋面前移速度14~17米/秒 ,最大19.5米/秒 ,瞬时最大风…  相似文献   
8.
张小曳 《科学通报》1991,36(19):1487-1487
一、采样及实验 利用单孔巴托耳型分级撞击式采样器(美国国际质子激发X荧光(PIXE)公司)采集了1990年4月三次尘暴期间及尘暴后气溶胶样品。第一次是4月6日在西安(34.3°N 108.9°E)(尘暴Ⅰ);第二次是4月10日在宁夏沙坡头(37.5°N 104.9°E),北京(39.9°N 116.4°E)和11日在西安(尘暴Ⅱ);第三次是4月25日在北京(尘暴Ⅲ)。据陕西省气象局提供的极轨  相似文献   
9.
青岛地区一次浮尘过程的来源及向海输尘强度   总被引:8,自引:1,他引:8  
李安春 《科学通报》1997,42(18):1990-1992
每年春季我国西北地区时有尘暴发生,严重地区平均尘暴日数达30d以上,是著名亚洲粉尘的主要源地.国外有许多关于我国大陆粉尘被吹扬到太平洋的报告.美、日、韩等下风国家高度重视我国大陆浮尘的来源、组成及强度等,有关学者对此进行了大量研究.我国内陆尘暴的研究已取得可喜成果,近年来海洋气溶胶化学元素组成等也已有报道,但是,沿岸和海上的尘暴观测和研究尚未涉及.我国的渤、黄、东海位于西北风的下风方向和东亚粉尘向太平洋输送的通道上,在其沿岸进行浮尘的观测研究对水土保持、海洋环境评价与保护和海洋沉积学以及全球变化研究等都是十分必要的.因此,根据地面观测、天气图和卫星云图分析以及粉尘和降尘的测量和分析结果,对1995年3月11~12日青岛地区出现的严重浮尘天气过程的来源以及通过量等进行了研究.  相似文献   
10.
A new regional dust model suitable for simulation and forecasting of dust storms over northern China was described. The dust model was developed by coupling the mesoscale dynamics model MM5 (the Fifth-Generation NCAR/Penn State Mesoscale Model) with a set of mass conservation equations for the particles. The model includes all the atmospheric physical processes of dust storms including occurrence, lifting, transport, and dry and wet deposition. It considers the parameterization of dry and wet deposition, the dust size distribution and microphysical processes in detail. The dust flux from the surface is parameterized based on the friction velocity, which is provided by the mesoscale nonhydrostatic dynamics model, which takes account of the vegetation coverage, land use, soil category, and soil moisture. This new dust model is used to simulate the dust storm that occurred on 19--21 March, 2002 in North China. The results show that there is high dust concentration and its movement is consistent with the surface weather record and satellite monitoring images of the observed dust storm. The simulated dust concentration coincides with the observation data of the particulate concentration of PM10 (dust particles smallerthan 10 μm in diameter). The new numerical model also successfully simulates the formation and migration of the dust storm of 6-8 April, 2002 in North China.  相似文献   
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