物理海洋学 期末复习资料完

1. inertial period (惯性周期P135)：It is one half the time required for the rotation of a local plane on Earths surface2. geostrophic balance (地转平衡P151):Within the oceans interior away from the top and bottom Ekman layers, for horizontal distances exceeding a few tens of kilometers, and for times exceeding a few days, horizontal pressure gradients in the ocean almost exactly balance the Coriolis force resulting from horizontal currents. This balance is known as the geostrophic balance.3. pressure gradient (压力梯度): In atmospheric sciences (meteorology, climatology and related fields), the pressure gradient (typically of air, more generally of any fluid) is a physical quantity that describes which direction and at what rate the pressure changes the most rapidly around a particular location. The pressure gradient is a dimensional quantity expressed in units of pressure per unit length. The SI unit is pascal per metre (Pa/m). 4. mixed layer (混合层P81) :Wind blowing on the ocean stirs the upper layers leading to a thin mixed layer at the sea surface having constant temperature and salinity from the surface down to a depth where the values differ from those at the surface. The magnitude of the difference is arbitrary, but typically the temperature at the bottom of the layer must be no more than 0.020.1 colder than at the surface./ The oceanic or limnological mixed layer is a layer in which active turbulence has homogenized some range of depth 5. Physical Oceanography(物理海洋学P8):Physical Oceanography is the study of physical properties and dynamics of the ocean. The primary interests are the interaction of the ocean with the atmosphere, the oceanic heat budget, water mass formation, currents, and coastal dynamics. Physical Oceanography is considered by many to be a subdiscipline of geophysics.6. The Ekman number(埃克曼数P139) is a dimensionless number used in describing geophysical phenomena in the oceans and atmosphere. It characterises the ratio of viscous forces in a fluid to the fictitious forces arising from planetary rotation. It is named after the Swedish oceanographer Vagn Walfrid Ekman.7. thermocline (温跃层P82)：Below the mixed layer, water temperature decreases rapidly with depth except at high latitudes. The range of depths where the rate of change, the gradient of temperature, is large is called the8. double diffusion (双扩散P130-131)：Here's what happens. Heat diffuses across the interface faster than salt, leading to a thin, cold, salty layer between the two initial layers. The cold salty layer is more dense than the cold, less-salty layer below, and the water in the layer sinks. Because the layer is thin, the fluid sinks in fingers 1-5cm in diameter and 10s of centimeters long, not much different in size and shape from our fingers. This is salt fingering. Because two constituents diffuse across the interface, the process is called double diffusion.p1319. salinity(盐度):(P73-75) At the simplest level, salinity is the total amount of dissolved material ingrams in one kilogram of sea water. Thus salinity is a dimensionless quantity. It has no units. 10. Reynolds number (雷诺数P116) : In fluid mechanics, the Reynolds number (Re) is a dimensionless number that gives a measure of the ratio of inertial forces to viscous forces and consequently quantifies the relative importance of these two types of forces for given flow conditions.11. Coriolis Force (科氏力P133-134) Is the dominant pseudo-force influencing motion in a coor-dinate system fixed to the earth.12. Potential Temperature(位温P85) Potential temperature is defined as the temperature of a parcel of water at the sea surface after it has been raised adiabatically from some depth in the ocean.13.青藏高原对气候的意义及附近海洋的影响 (P42-43)Maps of surface winds change somewhat with the seasons. The largest changes are in the Indian Ocean and the western Pacific Ocean.Both regions are strongly influenced by the Asian monsoon. In winter, the cold air mass over Siberia creates a region of high pressure at the surface, and cold air blows southeastward across Japan and on across the hot Kuroshio, extracting heat from the ocean. In summer, the thermal low over Tibet draws warm, moist air from the Indian Ocean leading to the rainy season over India.14. 科氏力推导15. 压强梯度力推导：压强梯度力并不是真正意义上的力，它实际是由于气压不同而产生的空气加速度（即单位质量所受的力）。它是产生从高气压向低气压的空气加速度的原因，产生风。常指空气的水平运动。16. 地转流水平压强梯度力和科氏力达到平衡时的稳定海流，叫做地转流。一、地转流的成因斜压场水平压强梯度力海水在受力方向上运动科氏力水平压强梯度力=科氏力地转流二、地转流方程及其解设等压面只沿x方向倾斜，夹角为,则有 （6-22） （6-23）由（6-22）得 （6-24） 根据等压面方程，有 （6-25）利用式（623）可得 由图可知 （6-27）所以 （6-28） 由（6 28）式知：内压场引起的地转流流速v：与等压面倾角的正切成正比；与科氏参量f成反比；随深度增大而减小；等压面与等势面平行时，流速为零在赤道处：，f=0,式(628)不适用。 外压场引起的地转流（倾斜流）：自表至底(不考虑底摩擦)流速相同地转流流向：在等压面与等势面的交线上流动；在北半球垂直指向压强梯度力的右方；观测者顺流而立时，右侧等压面高，左侧低。在南半球正好相反。17. 风海流一. 无限深海风海流1.基本假定：北半球；稳定风场