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Satellite Altimetry

其他書名	Attempts to Progress Beyond Studies of the Statistics of Mesoscale Variability
出版	Defense Technical Information Center, 1993
URL	http://books.google.com.hk/books?id=AteONwAACAAJ&hl=&source=gbs_api

註釋Because of uncertainties in the marine geoid and orbit height, most applications of altimetric data have focused on mapping the sea level variance statistic. These studies have been very successful at defining the geographical distribution of eddy variability and have highlighted the close relationship between transient eddies, the intensity of the mean flow and the bathymetry. Altimeter data have also been used to estimate surface geostropic velocities and map the variance of geostropic velocity (or, equivalently, the geostrophic Reynolds stresses). These studies have demonstrated the importance of the transport of horizontal momentum into the mean flow by transient eddies. Other obvious applications of altimeter data include mapping the time evolution of the sea level field for studies of wind and buoyancy forced ocean circulation and descriptive studies of mesoscale processes such as meandering and ring formation. Such applications are limited by a number of difficult technical challenges, mostly related to uncertainties about what space and time scales can be resolved by the complex space-time sampling characteristics of satellite data. A method is presented here for identifying aliasing patterns in an arbitrary sample design and for quantifying the resolution capability of the data set. Although the discussion emphasizes altimeter data, the method is applicable to any irregularly sampled data set. The maximum resolution capability of the GEOSAT orbit configuration (neglecting measurement errors and data dropouts) is found to be about 3 deg in latitude and longitude by 30 days.