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DTIC_ DiII 269 S ELECTE rAD-A267 JUL.2 91 993 A FINAL REPORT TO ONR Grant #N00014-92-J-1205: KERE Hydrographic/Tracer Studies PI: Alan M. Shiller, Center for Marine Science, University of Southern Mississippi This project involved making a closely-spaced hydrographic section across the Kuroshio near the point where it departs from the Japanese coast. The survey was made in July 1992 with 18 stations occupied on a line extending from 370N, 142 0E to 330N, 1440 E. Water samples were analyzed for 02, SiOs, NO0, and P0 and a CTD provided T and S. A detailed 4 ana ysis has been made of these sections. Following is a summary of our conclusions: a) Volume transport of the Kuroshio (based on qeostrophic calculations) was 81 Sv, which compares well with previous estimates. b) Vertical mixing processes beneath the Kuroshio frontal zone can bring intermediate depth waters to the near surface. The patchy nature of this water suggests that the vertical mixing is not continuous. If this mixing is the result of upwelling due to divergence associated with the anticyclonic turning of the Kuroshio, then changes in the meandering may explain its apparent intermittence. c) Lateral mixing of intermediate waters across the section also appears to be patchy as evidenced by considerable isonycnal variability in temperature and salinity. d) A south-flowing deep western boundary current is observed at intermediate depth in this section (based on silica anomalies and dynamic properties). This observation is consistent with observations by others to the north of the KERE section. e) A north-flowing abyssal current is observed associated with the Japan Trench. This observation is consistent with previous observations by others both north and south of the KERE section. f) There is a dynamic interaction between the Kuroshio and the Kashima 1 Seamount (which rises to -4000 m from the Japan Trench). The Kuroshio appears to depress isopleths over the seamount (presumably affecting the abyssal current); while the seamount results in a doming of the isotachs of the Kuroshio. We note that if a coarser, more traditional spacing of the hydrographic stations had been used, much of the detail which led to the above conclusions would have been missed. S93-16936 Thi= document hag been approved fr public releae and se; its ditriution is unlimited During the cruise moored instrumentation and drifters were deployed as part of other aspects of the KERE field program. Data from those instruments will help quantify the observations described here. Attached are copies of the sections. Accezion For U;,C "." ,- J~:111 C.,,(cid:127)q . ... ..U. ....... By DistHibutic.1 I Availablity Ccoes Avail and: or Dist Special A-I I DTIC QUALITY ii-PkCTED 5 + a. aV + r-4 00 a 0 04 0 000.4 z9 U)N 0C', I-- I~I I I I I I I I I I I I : 1 L0 14 C)J r4I Iq _ it i -i ... .. .. .. ofr .... ...... . .. .. ... ..I... .... .... ...... . ...... 0 C4 L. ................. _ 0 C 0 I 0 0 .......0....1...i.......... ...... 0 ".......... . .. . 0 - ------ ......... - .... .......-......- y_ C0 % LO . .. .. .. .. ..... . . . K7lI 1 0 I I C) 0 .. . .. .. ... .. . 1 .... ..... .... jl II / 0 in 0 o I-,....I *1- -0 _____q_______ LO 1~ 11 1 ..... ....... .. ... .. . . A . t .... ... ..... .... . .. ... ...... ... ... ... 0 0I . ..... .... . .. .... .... . 0__ 0__0 _C__ 0 0 0) 0 0C0 0 0 0 0D 0 0 0 0 0D 0 0 0* m0 00 v-I NO 10 __ .................... .. ..... .. ....... ............-'. V_ _ 0~~ ___ 0 I,.. . . .... ............ '~. .... .. .... .... .. .. . A .... . .... ._ ... ... ... _ L.O. . 4. .. .. ....... ....1.1.4. ... H4 ....... ! ........ . ... . ... L .... Cr) --- ----I -I-- - ... . ...... .. ............ J- In.... ll . o4 ... 1....... H 1 11 1.11 1 1 1 11 11 1 11 1 1 1 11 1 1 I L T T u h 1___ 11_ 0 C)1 liC0CC __ ! 0 C) . 0___ CN / ____ Ii4 I 40 LOI %D___ .......... l**?III I lq________ THIS PAGE IS MISSING IN ORIGINAL DOCUMENT lu 0 4o 1 ~ ~ 'U _____C_ 0 Cf) o C) cot v-I 4 M' l 10 44c 4 4 4 4 4 4 4 4 4 a 4 4 ~ '~ 0 o 00 w- 44 4 4 q 4 4 40 4 4 Ol) 4 40 U') n 444 4 4 4 4 4 4 4 4 4 4 4 4 %00 ~ 0 C 4 44 4 441 4 4 4 H - 40-4 .0 0 C> 0 0 0 0 0 0 00 0 i- q m V In (wu) qqdeaa 000 lriiI~r~rirvC NC 0 IN LO H / C) 0cq CO 44 ) 4 4 4 41 4 4 4 4 4 n 4 q -4 'o 00 0~ LO I I _ _ _ l i li "~ 40 44 44 4 4V 4 4 4 ~~(w 44) 444 44 4 __________ _ __ 0 LL * 7' LN... O________ O Li -2 IC) r,, i- 4 4 4 _ N CU4 _______ ,__"_ _0 01 0 4 0 0 0__0 ~ _ _ _ _ _ _ .0 N _______ O 44f4n4 4 _ __ _ _ _ _ _ 0 00 0 C rl M c g LO .0 0 44 (w , ,4la - (V)