The procedures and images presented here are the results of experiments with remote 

 site data in east Asia, principally the Yellow Sea, Sea of Japan, and the Sea of Okhotsk. 

 There exist many advantages of this region for experiments of this nature . The Sea of 

 Japan and Yellow Sea are marine basins of contrasting character. The Yellow Sea is a 

 shallow basin (maximum depth 100 m) of strong tidal current activity, major rivers and 

 deltas, and much runoff containing a relatively high suspended sediment load (fig, 1). 

 The Korean Strait (between Korea and Japan) is also of continental shelf depth, 203 m. 

 in the west channel and 108 m in the east channel with bottom dropping off steeply just 

 north of the strait. The Sea of Japan is a deep basin (3000 m), having small tide ranges 

 (< 15 cm), no major rivers, and is surrounded by narrow cor,tinentaI shelves. The Sea of 

 Okhotsk in winter has abundant sea ice, of which the VHR data provides excellent images 



(fig. 4). 



Strong thermal gradients occur in the surface waters of the Sea of Japan (fig. 9). In 

 the region off the east coast of Korea and in the Korean Strait (see Fig. 1) three and 

 sometimes four water masses occur, depending on season (Gong, 1971). The surface 

 temperature differences between them vary from 4-8°C. The Tsushima Current, a branch 

 of the Kuroshio (a western boundary current equivalent to the Gulf Stream), provides a 

 "jet" of warm surface water through the Korean Strait into the Sea of Japan (Figs. 5, 6, 

 and 9). The temperatures detected in this area by shipborne measurements ranged from 

 14-24°C (October, November 1972). The Tsushima Current waters here range between 20- 

 24°C, the Korean Coastal waters between 17-19°C, and the upwelling waters between 

 14-16° . These bodies of water had strong thermal gradients separating them in order of 

 2.4°C per nautical mile (see figure 11). Because of these steep gradients, fronts, frontal 

 waves, mesoscale cyclonic and anticycionic eddies are sharply defined in this region by 

 the gross 1.6°C temperature bands represented by each successive Mil X4 gray shade. 

 In the Yellow Sea the horizontal thermal gradients are much weaker (figs. 6 and 7), due 

 to the smaller inflow of warm waters and vertical mixing accomplished by the strong tidal 

 currents. 



The HRIR data actually mapped the surface extent of the ocean currents and fronts, 

 showing them outlined by the gray-shade patterns (see Tsushima Current, figure 5, 6, 

 Yellow Sea Warm Current, figure 6, and Yellow Sea Cold Current, figure 7). The DAPP 

 operators, with HRIR data on effective radiation temperatures of the sea can thus provide 

 search and rescue units information on water temperatures and in the case of known ocean 

 currents, probable direction of drift. During oceanographic operation NUGGET RANCH 

 (10 October - 10 November 1972) the synoptic HRIR data were used to supplement direct 

 sea surface temperature measurements, for decision making on spacing and positioning of 

 ship tracks, to detect and position water masses, and to measure water mass boundary 

 translocations, rather than to substitute for standard oceanographic methods. 



The VHR data appear to show the ocean floor to depths of 10 fathoms (60 feet). If 

 this suspicion is sustained by future field tests the DAPP system may have some use in 

 detection and verification of ship reports of dangerous shoal waters in poorly surveyed 

 oceanic areas*. The detection of sea ice in the Sea of Okhotsk is illustrated in Figure 4. 



* However except for high repetition rate this function can better be performed by 

 higher resolution systems such as ERTS or various photographic systems. 



9 



