Dynamical implications of Jupiter's tropospheric ammonia abundance     

Adam P. Showman  Imke de Pater 《Icarus》2005,174(1):192-204

Groundbased radio observations indicate that Jupiter's ammonia is globally depleted from 0.6 bars to at least 4-6 bars relative to the deep abundance of ∼3 times solar, a fact that has so far defied explanation. The observations also indicate that (i) the depletion is greater in belts than zones, and (ii) the greatest depletion occurs within Jupiter's local 5-μm hot spots, which have recently been detected at radio wavelengths. Here, we first show that both the global depletion and its belt-zone variation can be explained by a simple model for the interaction of moist convection with Jupiter's cloud-layer circulation. If the global depletion is dynamical in origin, then important endmember models for the belt-zone circulation can be ruled out. Next, we show that the radio observations of Jupiter's 5-μm hot spots imply that the equatorial wave inferred to cause hot spots induces vertical parcel oscillation of a factor of ∼2 in pressure near the 2-bar level, which places important constraints on hot-spot dynamics. Finally, using spatially resolved radio maps, we demonstrate that low-latitude features exceeding ∼4000 km diameter, such as the equatorial plumes and large vortices, are also depleted in ammonia from 0.6 bars to at least 2 bars relative to the deep abundance of 3 times solar. If any low-latitude features exist that contain 3-times-solar ammonia up to the 0.6-bar ammonia condensation level, they must have diameters less than ∼4000 km.  相似文献   

南海北缘北东东向构造活动性研究     

任镇寰  任奔滔  罗振暖  陈益明  钟贻军 《大地测量与地球动力学》1996,(2)

从地形地貌特征、重磁地球物理场、深部构造与断裂构造以及地震活动、震源机制等多方面论述北东东向构造是南海北缘的主要活动构造。对于长期以来认为新华夏系北东向构造是该区主要活动构造的观点来说，这是一种新的学术思想。  相似文献   

关于国有地了企业经营者实行年薪制的构想     

胡芳 《河南国土资源》1996,(2)

为建立社会主义市场经济的地矿工作新秩序，本文对国有地矿企业的经营者（厂长、经理）这一特殊群体进行了分析。着重研究了新形势下企业经营者实行年薪制的问题。指出年薪制就是以企业一个生产经营周期为单位确定经营者的报酬，这一周期通常为一年。进而阐述了为什么要实行企业经营者年薪制；企业经营者的收入应与职工工资完全脱钩；采用基础报酬加效益报酬的方法确定收入等等。并构想了实行经营者年薪制所需要的外部环境：建立经营者人才市场、经营者要能进能出、实行任职资格制度、建立风险机制、按劳动力市场经济规律办事。  相似文献   

DEVELOPMENT STRATEGIES OF WATER AND LAND RESOURCES IN THE HEXI REGION,CHINA     

肖洪浪  高前兆  李福兴 《中国地理科学(英文版)》1996,(1)

ＤＥＶＥＬＯＰＭＥＮＴＳＴＲＡＴＥＧＩＥＳＯＦＷＡＴＥＲＡＮＤＬＡＮＤＲＥＳＯＵＲＣＥＳＩＮＴＨＥＨＥＸＩＲＥＧＩＯＮ，ＣＨＩＮＡ肖洪浪，高前兆，李福兴ＤＥＶＥＬＯＰＭＥＮＴＳＴＲＡＴＥＧＩＥＳＯＦＷＡＴＥＲＡＮＤＬＡＮＤＲＥＳＯＵＲＣＥＳＩＮＴＨＥ...  相似文献   

A new radiolarian species Clathrocorys gracilis from northern South China Sea     

Wang Jinbao  Li Xinzheng  Tan Zhiyuan 《中国海洋湖沼学报》2005,23(1):118-120

A new species,Clathrocorys gracilis nov. spec. of Tripocyrtidae (Radiolarians: Nassellaria) from surface water in northern South China Sea, is described in this paper. The new species has four radial beams arising from the cephalic base centre, each foot with cup-shaped structure and ramified bar in the proximal section (near cephalic base), and each wing with a large mesh in the middle, a medium mesh and a small mesh on each side respectively. Project supported by the NSFC (No. 40276044) and the Chinese Academy of Sciences (No. KSCX2-SW-101B).  相似文献   

Tidal effects on temperature front in the Yellow Sea   总被引：5，自引：0，他引：5  

Ma Jian  Qiao Fangli  Xia Changshui  Yang Yongzeng 《中国海洋湖沼学报》2004,22(3):314-321

Temperature front (TF) is one of the important features in the Yellow Sea, which forms in spring, thrives in summer, and fades in autumn as thermocline declines. TF intensity ⋎S _T ⋎ is defined to describe the distribution of TF. Based on the MASNUM wave-tide-circulation coupled model, temperature distribution in the Yellow Sea was simulated with and without tidal effects. Along 36°N, distribution of TF from the simulated results are compared with the observations, and a quantitative analysis is introduced to evaluate the tidal effects on the forming and maintaining processes of the TF. Tidal mixing and the circulation structure adapting to it are the main causes of the TF. Supported by the National Basic Research Program of China (No. G1999043809) and the National Science Foundation of China (No. 49736190).  相似文献   

三峡重庆库区深部地球物理特征与断裂构造   总被引：1，自引：0，他引：1  

胡建平  赵军龙  汪文秉  李娜 《地球科学与环境学报》2005,27(3):49-54

为了深入研究三峡重庆库区岩石圈动力学特征及其对断裂构造活动的控制和影响．并为之提供基础资料，为三峡重庆库区地震、地质灾害的监测与防治提供基础依据，在已有地球物理资料的基础上，从综合地球物理研究角度出发，通过实测地震测线资料的再解释．采用新的处理技术方法，对本区的东西向主剖面和南北向支测线的地震测深资料进行二维射线追踪处理、Pg波成像；选用场分离技术、位移数字成像技术重新处理了重力和航磁资料，通过联合反演来建立深部二维构造剖面，对剖面所揭示的基底构造特征和地壳结构特征、主要断裂构造特征以及莫霍面的起伏特征进行了精细分析和细致研究．从地球物理平面场特征出发建立了岩石圈构造三维框架。研究结果表明，这样的研究思路准确、方法得当．结论可靠；沿该剖面，把可解译的断裂分为Ⅲ级：Ⅰ级为超岩石圈断裂；Ⅱ级为壳断裂；Ⅲ级为盖层断裂。依据地球物理特征，准确揭示了库区的断裂构造特征，达到了预期效果。  相似文献   

Dwarf nova oscillations and quasi-periodic oscillations in cataclysmic variables – IV. Observations of frequency doubling and tripling in VW Hyi     

Brian Warner  Patrick A. Woudt 《Monthly notices of the Royal Astronomical Society》2006,367(4):1562-1576

We present new observations of the rapid oscillations in the dwarf nova VW Hyi, made late in outburst. These dwarf nova oscillations (DNOs) increase in period until they reach 33 s, when a transition to a strong 1st harmonic and weak fundamental takes place. After further period increase, the 2nd harmonic appears; often all three components are present simultaneously. This 1:2:3 frequency suite is similar to what has been seen in some neutron star and black hole X-ray binaries, but has not previously been seen in a cataclysmic variable. When studied in detail, the fundamental and 2nd harmonic vary similarly in phase, but the 1st harmonic behaves independently, though keeping close to twice the frequency of the fundamental. The fundamental period of the DNOs, as directly observed or inferred from the harmonics, increases to ∼100 s before the oscillation disappears as the star reaches quiescence. Its maximum period is close to that of the 'longer-period' DNOs observed in VW Hyi. The quasi-periodic oscillations (QPOs), which have fundamental periods 400–1000 s, behave in the same way, showing 1st and 2nd harmonics at approximately the same times as the DNOs. We explore some possible models. One in which the existence of the 1st harmonic is due to the transition from viewing a single accretion region to viewing two regions, and the rate of accretion on to the primary is modulated at the frequency of the 1st harmonic, as in the 'beat frequency model', can generate the suite of DNO frequencies observed. But the behaviour of the QPOs is not yet understood.  相似文献   

Management of the UK mackerel fisheries: An economic perspective     

David J. Whitmarsh  James A. Young 《Marine Policy》1985,9(3):220-236

  相似文献   

甘新蒙北山地区成矿带划分和基本特征对比   总被引：3，自引：1，他引：2  

彭巨贵  张发荣  赵福昌 《地球科学与环境学报》2006,28(3):11-18

在对甘新蒙北山地区成矿地质背景和成矿在时空上的联系性等综合研究分析基础上,运用新理论、新认识,以板块构造单元划分为基础,将本区划分为3个Ⅲ级成矿带、11个Ⅳ级成矿带,并对Ⅲ级成矿带特征进行了阐述,以期为矿产勘查和地质大调查工作部署提供新的思路和依据。进一步就主要矿床(点)、构造单元、矿种、赋矿建造、控矿因素、成矿类型、成矿时代等方面进行了对比,认为各Ⅳ级成矿带在区域上具有相对稳定的展布范围,具有相同的构造环境和成矿条件、类似的矿种和成矿时代,存在一定的相似性、可比性,并且各成矿带具有一定的潜在找矿价值。  相似文献