Tap chi Khoa hoc va Cong nghe biin T9 (2009) S6 4; Tr 25 - 37 DAC DIEM PHAN BO CAC DAC TRimC SONG TAI VUNG BIEN VEN BO TiNH BINH THUAN LE DINH MAU Tom tat: Bdi bdo trinh bdy kit qud tinh todn truang cao song hihi hieu (Hs) tgi ddi ven bien tinh Binh Thudn img voi cdc truang gio miia dien hinh vd cue dgi Cdc dgc trung gio duac thong ke tic chuoi so lieu gio dgc tgi trgm ddo Phu Quy (1987-2007) Cdc tham so song viing khai duac tinh bdng mo hinh - Dolphin Cdc tham so song viing nuac nong ven ba duac tinh bdng mo hinh SWAN Kit qud nghiin cicu cho thdy ddi ven bo tinh Binh Thudn hi tdc dong mgnh ciia song cd hai miia gio Dong Bdc vd Tdy Nam vai cao song trung binh tgi khu vice ven bd Id Hs ~ - m Trong thai ky 1987 - 2007, khu vuc nghien cicu co gio mgnh cue dgi vai toe V = 28 m/s, hudng NE, chiing gdy song co cao cue dgi ngoai khai Id Hs ~ - m; vd gio V = 36 m/s, hudng SW, chiing gdy song co cao cue dgi ngoai khai Id Hs~ ~ m Cdc miii ddt nho biin, cdc ddo ven ba, phdn bo sau vimg ven ba CO vai tro rdt quan trong viic phdn bo ndng luang song tgi khu vuc nghien cicu Kit qud tinh toan cdc trudng song trin phuc vu viic thiit ki, xdy dung cdc thiiy cong trinh cimg nhu cdc hoat dong kinh ti, du lich vd bdo vi moi truang viing ven bd khu vuc nghiin cicu Bill bdo la tam ldng ghi ffn ciia tdc gid girl tdi PGS TS Vo Van Lanh (nguyen Vien Tnrdng Vien Hdi dwffng hoc) Ngirdi dd ddnh trgn cuoc ddi cong hien cho sir nghiep phdt trim nganh hdi dwffng hoc Viet Nam; cdng nhir viec ddo tao, boi dw&ng the he ciic nhd khoa hpc hdi dwffng tre co tdc gid - Nhirng thugt ngic chinh diing bdi: cdc ddc trung song, cao song hicu hiiu (Hs), gio miia Dong Bdc (NE), gio miia Tdy Nam (SW), ddi ven ba biin, mui ddt LMODAU Tinh toan cac dac trung song tai viing bien ven bd da dugc tien hanh nghien cim tai nhieu vien thiiy luc tren The gidi nhu Trung tam Thiiy lire Ha Lan (Delft Hydraulics) vdi bg chuang trinh SWAN (Booij and Holthuijsen, 1999); Vien Thiiy luc Dan Mach vdi bg chuang trinh MIKE 21, MIKE 3; Trung tam C6ng nghe ven bd cua quan dpi My vdi bg chuang trinh RCPWAVE (Ebersole, Cialone, and Prater, 1986) Tinh tdan cac dac trung sdng vimg khoi hien dugc ap dung rong rai nhit la m6 hinh WAM (WAMDI Group 1988); Dolphin (Mandal and Holthuijsen, 1985); STWAVE (Tolman, 1991) Ngoai cdn CO mgt sd md hinh tinh toan, du bao sdng eac dilu kien khac dugc xay dung d 25 cac trudng dai hgc va vien nghien eiiu khac vdi nhimg thi manh va nhiing han che rieng Tai Viet Nam nhiing nam gan day da c6 nhilu chuang trinh cip Quoc gia va du an hgp tac Qudc te tien hanh nghien ciiu cac qlia trinh thiiy-thach-dgng luc vimg ven bd, eo tinh toan cac dac trung song nhu dl tai KT.03.14, KHCN.06.08 (19962000), KC.09.05 (2001-2005) Du an Quoc tl "EU-Cim Long Projecf (1996-1998): nghien cim, du bao xdi Id tai bd bien Ganh Hao; du an Viet Nam-Thuy Dien (2004-2007): nghien cim xoi Id bd biln Hai Hau, Nam Dinh Tai dai ven bien Nam Trung bg tinh toan cac dac trung sdng da dugc tiln hanh bdi cac tac gia nhu: Biii Hdng Long, Le Dinh Mau (2003); Le Dinh Miu (2005a, 2005b, 2005c, 2006); Le Dinh Mau, et al (2007), nhung cong trinh tren da tiln hanh tinh song tai viing khoi va viing ven bd cac dieu kien tao song khac Tuy nhien, tai viing bien ven bd tinh Binh Thuan hau nhu viee nghien ciiu, tinh toan song chua dugc quan tam diing mite Cac tac gia Biii Hong Long, Le Dinh Miu (2000) mdi tiln hanh tinh toan trudng sdng khiic xa cac trudng gio dien hinh tai vinh Phan Thiet Kinh dQ (ihiclii'i: 11.2 - : dUcVng dan); sfiudn) 11.0 lO.i 10,6 107.6 r" T • '—I r 107.8 108.0 108.2 108.4 108.6 (Theo ban l^ 1^: 1/100.000 ciia Hai quan Nhan dan Vi^l Nam xuai bdn nam 1994) IC 109.0 Hinh 1: Dac diem khu vue nghien ciiu Trong bai bao nay, cac dac trung sdng tai khu vuc ven bd img vdi cac dilu kien tao song khac da dugc tinh toan theo qui trinh nhu sau: - Xae dinh cac trudng gi6 mua dien hinh va toe gid cue dai tit chu6i so lieu gio dae tai tram dao Phii Quy (1987 - 2007) 26 - Xae dinh cac dac trung sdng ngoai khoi viing bien Binh Thuan img vdi cac trudng gid khac bang md hinh tfnh song bien sau - Dolphin - Cac dac trung s6ng tai viing bien ven bd dugc tinh bang md hinh SWAN vdi dieu kien bien la sdng ngoai khoi, gid dia phuong va phan bo sau cua viing nghien cim - Cac dac trung song tai vimg bien ven bd dugc tinh t6an dieu kien khong c6 su dang/riit muc nudc tao bdi cac trudng gio Pham vi tinh toan ciia md hinh SWAN va dac diem khu vuc nghien cim dugc the hien tren hinh II NGUON SO LIEU VA PHlTONG PHAP TINH TOAN Nguon so lieu - So lieu gid dugc thu thap tit tram dao Phii Quy (1987 - 2007) tren 16 hudng - Do sau tai khu vue nghien cim duge lay tir hai dd ty le: 1/100.000 xuat ban nam 1994 ciia Hai quan Nhan dan Viet Nam - So lieu ve cac dac tnmg song dac dugc lay tit dgt khao sat 12/2008 eua Vien Hai duong hgc tai vinh Phan Thiet Nhirng so lieu dung de phuc vu tinh toan va kiem chiing mo hinh Phuong phap tinh toan a Tinh todn cdc dac trung song bien sau Mo hinh sd tri tinh song bien sau Dolphin (Mandal and Holthuijsen, 1985) dugc xay dung tai Vien Thiiy lire Ha Lan cho phep tinh toan ket hgp song gid va song limg Phuong trinh can bang nang lugng song hai chieu cho tradng hgp song gio tren hudng eia: ^ ^ = S,i0) + ]s,if,e)df , * (al) day, Ei(G) = mat nang lugng phd ciia song gid tren hudng (m^/rad.), Si(9) = tic bien doi cua Ei(9), neu Ei(9) nhd hon gidi han qui udc no dai dien cho trudng hgp s6ng dang phat trien, ngugc lai dai dien cho trudng hgp s6ng limg (m^/rad/s) S2(f, 9) = tic 27 chuyen giao cua nang lugng sdng limg chiiu E2(f, 9) sang song gio cd cimg tan s6 (m^/rad/Hz/s); = hudng s6ng tdi (rad); f = tan sl song (Hz) Phuang trinh can bang nang lugng s6ng hai chiiu trudng hgp song limg tit hudng dugc trinh bay bang phuang trinh sau: dF ^ = -Bs,,{f,e)-s,{f,e)-s,{f,e) (a2) dt day: - E2(f, 9) = mat nang lugng phd hai chieu cua phan song limg vdi tan so (f), hudng truyin (9) (mVrad/Hz/s); B = nlu Si 0; Su = tic biln dii ciia E2 tuong ling vdi Si Si co gia tri am (phan bd tan sd cua Si cd dau ngugc lai); 82 = tic chuyin giao ciia nang lugng song limg E2 sang s6ng gid co cimg tan so, (gia thiet gia tri E2 > 0) (m^/rad/Hz/s); S3 = toe bien ddi cua nang lugng song limg gay bdi hieu ling nudc nong (dimg cho trudng hgp nudc nong); - So lieu dau vao cua md hinh la: vi tri diem tinh, trudng gio (toe do, hudng), thdi gian tac dgng cua gid - Sd lieu dau ciia mo hinh la: cao sdng hiiu hieu (Hs), chu ky ciia dinh song (Tp), phan tan ciia nang lugng song (coefficient of spectral directional spreading DSPR) va hudng sdng (9) b Tinh todn cdc dac trung song viing nu&c ndng ven ba Cac dac trung sdng tai viing bien ven bd dugc xae dinh bang mo hinh so tri tinh song SWAN (Booij et al., 1999) SWAN dugc xay dung tren co sd phuang trinh can bang hoat dgng (spectral action balance equation) nhu sau: -N dt + ~C,N dx -' + —CN dy ' + -^C^N da ^ + —C,N^de ' a (bl) dday, N = mat ph6 hoat dgng (action density); t = thdi gian Cx, Cy = toe lan truyen ciia N theo tga khdng gian x va y Cc, Ce = tic biln ddi ciia N theo tan s6 tuong doiCTva hudng S = S(a, 9) la ham nguIn (mat nang lugng) dai dien cho qua trinh tao song (generation), phan huy (dissipation) va tuong tac phi tuyen giira sdng - sdng (nonlinear wave-wave interactions) va sdng-dong chay 28 Md hinh SWAN tinh hieu ling nudc nong, khiic xa, tao sdng gi6 dia phuong, song bac diu, tuong tac song-song, ma sat day, s6ng nhao, Pham vi ap dung mo hinh la toan bg vimg biln ven bd tinh Binh Thuan tir 107.6°E din 109.0°E va tir 10.6°N den 11.3°N vdi kich thudc ludi tinh la 1000 m x 1000 m (hinh 1) S6 lieu dau vao ciia mo hinh la: - Cac tham so song ngoai khoi: Hs, Tp, DSPR va chiing dugc lay tit ket qua cua mo hinh tinh song Dolphin - Trudng gio dia phuang (t6c do, hudng) - Phan bo sau cua vimg nghien cim So lieu dau ciia mo hinh la: cao s6ng hiiu hieu - Hs, hudng sdng trung binh - 9, chu ky cua dinh ph6 song - Tp, dai sdng tmng binh - L III KET QUA NGHIEN C U T J Dieu kien tu nhien fl Ddc diem dieu kien tir nhien lien quan den sir phdn bo cdc dac trung song viing ven b& Dudng bd bien tinh Binh Thuan (Ca Na - miii O Cap) chay theo hudng Dong Bac (NE) - Tay Nam (SW), hinh thai va cau tao tuang doi don gian va ddng nhat Cac miii dat nho bien dien hinh la Ca Na, La Gan, MUi Ne va Ke Ga Dao ven bd co tac dgng manh len sir truyen song la Cu Lao Cau Cac vinh d day deu tuong doi can va hd nhu Phan Rang, Ca Na, Phan Ri, Phan Thiet Them luc dia d day tuong doi trai rong dudng dang sau 10 m gan nhu chay ngdai cac cira vinh, dudng 30 m chay song song va each dudng bd ~ 20 km d phia Bac va ~ 50 - 60 km d phfa Nam (hinh 1) Do vay, nang lugng s6ng da bi suy giam nhieu tien vao khu vuc Do dudng bd chay theo hudng NE-SW nen nhirng khu vuc che chan sdng la cac miii dat nhd bien, tiiy theo miia gio ma cac miii dat se che chan song cho cac vinh ven bd Ca sdng NE va SW deu tac dgng manh den khu vuc Rieng song bao se bi suy giam dang ke lan truyen vao khu vuc Dai ven bien tinh Binli Thuan nam giiia viing cd che trieu khac nhau: Quy Nhon (nhat trilu khdng diu) va Viing Tau (ban nhat trilu khdng diu) Do tilp giap vdi viing biln Ba Ria - Viing Tau nen dai ven bd nghien ciiu nhit la khu vuc tir Phan Thilt trd vao chiu anh hudng nhieu ciia thiiy trilu Vung Tau Nhin chung, sd nhat trilu dao dgng tir 10 den 15 Thdi gian trilu dang thudng dai hon thdi gian trilu xudng Do 29 ldn trieu » 1.5 - 2.0 m, ky nudc cudng ndi chung bien trilu it thay doi tren mdt dai bd bien dai Viing bien nghien cim the hien ro tinh chat bien doi miia ciia chi gio: gi6 miia NE (vao miia dong) vdi toe dat den - m/s va tan suat xuat hien den 20% thinh hanh tit thang 11 din thang 3; gid miia SW (vao miia he) vdi toe dat din - m/s va tin suit xuit hien din 10% thinh hanh tit thang din thang Thang 10 va thang la hai thang chuyin,tilp Gid mua mua dong manh hon gid miia miia he ca ve site gid lan ve thdi gian tac dgngi T6c gid mua d6ng tang din tit thang 10, dat gia tri ldn nhat vao thang 12 - 1, sau d6 giani d4h.' Gid miia miia he bit dau vao thang va dat gia tri ldn nhat vao thang - Thudng thi eudng gi6 miia miia he vao nita dau yeu hon vao nita sau cua miia Biln dgng ciia gid miia va gid tin phong vao miia d6ng the hien chii yeu dao dgng eua tic gio, cdn hudng gid hiu nhu kh6ng thay d6i Dac diem cau true va dgng luc viing nghien cim cdn chiu anh hudng cua gid manh cac trudng hgp thdi tiet dac biet nhu bao va ap thip nhiet ddi Trung binh mgt nam cd 1.5 bao di qua viing bien nay, thudng la vao thdi ky thang den thang 12 Viing bien gan bd cdn chiu tac dgng cua gio dat-bien (breeze) Trong thdi gian dem tdc gid thudng bien doi (trir nhirng trudng hgp CO bao hoac ap thap nhiet ddi) nhu sau: ban dem va bu6i sang gid lang hay yeu, ban tdc gid tang va ve dem lai giam (Nguyen Kim Vinh, 1997) b Dac diem che gio qua phdn tich, thong ke chuoi so lieu gio dac nhieu ndm Toe gio tai mgt vi tri ven bd cd vai tro quan trgng viec tao song, dong chay, nudc dang, van chuyen bun-cat, xdi Id-bdi tu dudng bd, neo dau tau thuyen, De danh gia cac dac trung che gid tai khu vuc nghien cim da sit dung ngu6n so lieu gio tai tram dao Phii Quy vdi chu6i s6 lieu gio dac tit 1987 den 2007, tan suat sd lieu la tieng mgt lan tai cac gid 1,7, 13, 19 gid Ket qua phan tfch, thdng ke cho thay: - Thdi ky gio mua NE: co hai hudng gio chfnh la hudng NE chilm tin suit 34.83%, day la hudng xuat hien nhieu nhat khu vuc nghien cim, thdi gian hudng NE keo dai c6 the dat 137 va hudng thii hai la NNE vdi tan suat xuat hien khoang 14%) vdi thdi gian tri cue dai la 49 - Thdi ky gid miia SW: co hudng gio dai dien Hudng W vdi tan suit xuit hien 15.96%), thdi gian tri cue dai la 23 ngay; hudng WSW vdi tan suat xuit hien 10.09%, thdi gian tri dai nhit la 14 ngay; hudng SW vdi tan suit xuit hien khoang 11.19%, co thdi gian tri cao nhat co the dat 57 - Hai hudng gio gay song chii ylu la NE va SW tuong ling vdi mua gio NE va SW Cac dgt gid mua dien hinh ve thdi gian keo dai va cudng la trudng gio vdi tie V = 30 12 m/s (tuong duong gid miia cip 6) Tdc gio cue dai V = 28 m/s xuat hien tai hudn^ NE va V = 36 m/s xuit hien tai hudng SW Dac diem phan bd tdc va hudng gid the hien tren hinh NNW NNE Toe gio (m/.s) • 2-4 [21>4-6 • >6-8 |^>10-12 • >12-14 I l>14-16 a>16-18 n>18-20 • >20 WNW W WSW SSW SSE Hinh 2: Phan bd t6c va hudng gid tai tram dao Phii Quy (1987 - 2007) Ket qua tinh toan cac dac trung song ngoai khoi viing bien Binh Thuan Tren co sd thong ke ehudi sd lieu gid dac tai tram dao Phii Quy (1987 - 2007), cac trudng gid sau day da dugc chgn de tinh tdan sdng: - Gid mua NE dien hinh: V = 12 m/s, hudng = NE - Gid miia S W diln hinh: V = 12 m/s, hudng = SW - Gid cue dai hudng NE: V = 28 m/s - Gid cue dai hudng SW: V = 36 m/s Ap dung md hinh tinh sdng biln sau - Dolphin, cac dac trung sdng ngoai khoi vimg biln Binh Thuan dugc trinh bay tai bang 31 Bang 1: Cac dac trung sdng ngoai khoi viing biln tinh Binh Thuan Toe gio - V (m/s) 12 28 36 Do cao s6ng hiiu hieu - Hs (m) 2.1 6.6 9.5 Chu ky song - Tp (s) 6.3 10.1 12.2 He so phan tan eiia song - DSPR (o) 27.2 27.0 26.8 Dac dilm phan bo cac dac trung song tai vung bien ven bd tinh Binh Thuan So lieu diu vao ciia md hinh SWAN la cac dac trung sdng ngoai khai (lay tir ket qua tinh toan cua md hinh Dolphin), gid dia phuong va phan bo sau Ket qua tinh toan dugc the hien tren cac hinh ^ : Kin ft dp Ohi (hli: 11.2 : hifdng sdng - : 6]iiing dang d() cao so'ng (m) 110 •a '/.'////.y////////: 10.8^ v^^y^/y^^^ iyyy^^i/yyl/AA7^^/A/j'y.'. ^ >'^,'^yAA''Ay^/Ayyy^7/>Ar'v,/V>7^^l/y^^^//Ay^>' •.^.^y^,^AA^.'.r^.r.^AAJAAA.,.,',,.^.^.f//AAA*//fA//A//f/f/^/J, •A.,f-,0^A^./j^^A.^^A,',AAA7^7AA/'AV/AAA7/^/AA7-'-lliyA/Af/ -^.-y-T»-.-»-«-.-»-.^kr-«-*- iwirrr-r i-r'^fi/ir I'l'fr'r'^ fr^f^r / AA-i-A /Ai AAA A A/ AAAA A -fffr-' 'm-yiVrrMr^.^.^ 'AA^^r^J'.r^^^^ j- ttkAA /A/ AAA *J/ AAA AA/ AAAA A *^^AAA.^^^^^J^AAAAA>'yAAA AAA^A^ ^^^A^^/^AA^fA / ^jT^ fAJ AAA /A^AAA^^ _ HAMTA 10.6 107.6 «»>'" 108.4 108.6 ' 108.8 % ' 109.0 Hinh 6: Trudng cao sdng hiiu hieu tai vimg bien ven bd tinh Binh Thuan vdi trudng gid cue dai (Gio: V = 36 m/s; Hudng = SW) Nhan xet: - Dudi tac ddng ciia dgt gid miia NE, cap (V=12 m/s, hudng NE) (hinh 3), ta thay: toan dai ven bien Binh Thuan cd Hs ~ 1.0 - 1.5 m, hudng NE-E Dudng dang eao song Hs = 0.5 m dm sat dai ven bd; Hs = 1.0 m chay bao cac miii dat, dao ven bd va cira cac vinh; Hs = m chay each xa bd Khu vuc phia Bac Binh Thuan bi sdng NE tac dgng manh hon khu vuc phia Nam (do phan bd sau ciia dai ven bd va qua trinh sdng khue xa) Khu vuc phfa Nam cac miii Ca Na, La Gan, Miii Ne, Ke Ga tuong ddi kin sdng Nhin chung, miia gid NE dai ven bien Binh Thuan hi song tac dgng tuong d6i manh - Dudi tac dgng ciia dgt gid mua SW, cap (V = 12 m/s, hudng = SW) (hinh 4), ta thay: tren toan dai ven bien, cac viing, vinh ciia Binh Thuan bi tac dgng manh ciia song vdi Hs ~ 1.0 - 1.5 m, hudng SW-S Tuong tu mua gid NE, dudng dang cao song Hs = 0.5 m 6m sat dai ven bd; Hs = 1.5 m chay bao cac miii dat, dao ven bd va ciia eae vinh; Hs = m chay each xa bd So vdi mua gio NE (ciing cudng gio), song hudng SW tac dgng manh hon din khu vuc Binh Thuan Khu vuc phia Bac Binh Thuan bi song SW tac dgng nhe hon khu vuc phia Nam (do phan bo sau ciia dai ven bd va qua trinh sdng khiic xa) Khu vuc phfa Nam cac miii Ca Na, La Gan, Miii Ne, Ke Ga bi sdng tac dgng manh; ngugc lai, khu vuc phfa bic tuang dii kin song Dai ven bd phia Nam cac vinh song ylu hon dai 34 ven bd phia Bac cac vinh Nhin chung, miia gio SW dai ven bien Binh Thuan bi song tac dgng manh, tuong dii diu khip Nhu vay, dai ven bd Binh Thuan hi tac dgng manh bdi sdng ca miia gio NE va SW tiiy thudc vao vj tri che chan song cac miii dat, cac dao ven bd tao - Trong dieu kien gid cue dai (V = 28 m/s, hudng NE) (hinh 5), ta thay: toan dai ven bien Binh Thuan cd Hs ~ - m, hudng NE-E Dudng dang cao song Hs = m 6m sat dai ven bd; Hs = m chay bao cac miii dat, dao ven bd va cita cac vinh; Hs = m chay each xa bd Khu vuc phia Bac Binh Thuan bi sdng tac ddng manh hon khu vuc phfa Nam Khu vuc phfa Nam cac miii Ca Na, La Gan, Miii Ne, Ke Ga sdng tac dgng yeu hon khu vuc phfa Bac - Trong dieu kien gio cue dai (V = 36 m/s, hudng SW) (hinh 6), ta thay: toan dai ven bien Binh Thuan cd Hs ~ - m, hudng SW-S Dudng dang cao sdng Hs = m 6m sat dai ven bd; Hs = m chay bao cac miii dat, dao ven bd va cita cac vinh; Hs = m chay each xa bd IGiu vuc phia Bac Binh Thuan hi sdng tac dgng manh hon khu vue phia Nam Khu vuc phia Nam cac miii Ca Na, La Gan, miii Ne, Ke Ga sdng tac dgng manh hon khu vuc phia Bac IV KET LUAN Ket qua nghien ciiu cho thay: - Dai ven bien tinh Binh Thuan hi tac dgng manh bdi sdng ca hai thdi ky gid miia NE va SW Tuy nhien, them luc dia trai rong nen nang lugng sdng da bi tieu tan mgt phan kha ldn tmyen vao viing ven bd, nhat la khu vuc phia Nam Binh Thuan Do cao song hiiu hieu trung binh tren toan dai cac dgt gio miia dien hinh (cap 6) ~ - m, huong dao dgng NE-E (thdi ky gid miia NE) va SW-S (thdi ky gid miia SW) - Trong thdi ky tir 1987 - 2007, gid cue dai V = 28 m/s, hudng NE da gay song cd cao Hs == - m va hudng NE-E; gid cue dai V = 36 m/s, hudng SW da gay song ed cao Hs ~ - m va hudng SW-S tren tdan dai ven bien tinh Binh Thuan - Cac miii dat nhd bien, cac dao ven bd va phan bd sau cd vai tro rat quan trgng viec phan b6 nang lugng sdng tren tdan dai ven bien Binh Thuan Ldi cam on: Tac gia chan cam on cac ddng nghiep tai Phdng Vat Ly, Vien Hai duong hgc da nhiet tinh cung cip cac dir lieu vl chi gid tai vimg nghien ciiu va khuyin khich, dgng vien qua trinh hdan thien bai bao 35 TAI LIEU THAM KHAO Booij, N., Ris, R C , and Holthuijsen, L H., 1999 A third-generation wave model for coastal regions 1- Model description and validation Journal of Geophysical Research, 104 (C4), 7649-7666 Biii H6ng Long, Le Dinh Man, 2000 Cac dac diem cua trudng s6ng, anh hudng cua chiing tdi cac qua trinh xdi Id - b6i tu tai Cita Dai (Hgi An), cita sdng Cai (Nha Trang), vinh Phan Thiet cac dieu kien gio dia phuong dien hinh Tuyen tap Nghien ciiu biln, tap X, trang 21-33 NXB Ndng nghiep Danish Hydraulic Institute (DHI), 1998 MIKE Hydrodynamic module: User Guide and Reference Manual Release 2.7 Danish Hydraulic Institute (DHI), 2000 MIKE 21 User Guide and Manual Ebersole, B A., Cialone, M A., and-Prater, M D., 1986 Regional coastal processes numerical modeling system RCPWAVE - a linear wave propagation model for engineering use Technical Report CERC-86-4 Department of the Army, US Army Corps of Engineers, Washington, DC 20314-1000 Le Dinh Man, Biii Hong Long, 2003 Dac diem phan bd eac dac trung s6ng tai viing viin ven bd Tinh Phu Yen Tap chi KH&CN biln, T3 (2003), sl 3, tr 32-46 Le Dinh Man, 2005a Dac diem phan bd cac dac trung sdng tren Bien Dong cac dgt gid miia dien hinh Tap chi khoa hgc va c6ng nghe biln l(T.5)/2005, tr 2534 Le Dinh Man, 2005b Tinh toan cac dac trung s6ng bao tai vimg biln Khanh Hoa Tap chf KH&CN biln, 2(T.5)/2005, Ha Ngi, 1-17 ,: Le Dinh Mau, 2005e Tinh toan cae dac trung song tai viing nudc n6ng ven bd bing m6 hinh sd tri -SWAN Tap chf KH&CN biln (Phu traong), 4(T.5)/2005, Ha Ngi, 36-49 10 Le Dinh Mau, 2006 Tinh toan cac dac trung song biln khoi bing mo hinh sl tri WAM Tap chi KH&CN biln, 3(T.6)/2006, Ha Ngi, 26-39 11 Le Dinh Mau, G.N Nayak, and V Sanil Kumar, 2007 Shoreline change in and around the Thubon River Mouth, Central Vietnam Jour Indian Association of Sedimentologists, Vol.26, Nps 1&2 (2007), pp.45-51 12 Mandal, S., and Holthuijsen, L.H., 1985 A numerical wave prediction model DOLPHIN: Theory and test results Report No 3-85, Delft University of Technology, Department of Civil Engineering, Group of Fluid Mechanics 36 13 Nguyen Kim Vinh, 1997 Bien dgng cua gio d viing nudc tr6i manh Nam Trung bg Cac cong trinh nghien ciiu viing nudc troi manh Nam Trung bg NXB'KH&KT Tr 8-16 Nha Trang 14 Tolman, H L., 1991 A third-generation model for wind waves on slowly varying, unsteady and inhomogeneous depths and currents Journal of Physical Oceanography, 21, 782-797 15 WAMDI Group, 1988 The WAM model - A third generation ocean wave prediction model, J Phys Oceanogr., 18, 1775-1810 DISTRIBUTION FEATURES OF WAVE CHARACTERISTICS ALONG THE COAST OF BINH THUAN PROVINCE LE DINH MAU Summary: The calculated results of significant wave height fields (HJ along the coast of Binh Thuan Province corresponding to typical monsoon and maximum wind fields are presented Wind data were taken from Phu Quy Island Station (1987 - 2007) Wave characteristics in the offshore region were calculated by deep water wave model - Dolphin Wave characteristics in the nearshore region were calculated by SWAN model Studied results show that Binh Thuan Coast was seriously affected by wave action In both seasons (NE and SW monsoons) with mean significant wave height of to m During 1987 to 2007, the maximum winds have occurred at studied area with the velocity of 28 m/s and 36 m/s in NE and SW directions respectively: which generated significant wave height of to m and to m in the offshore region of studied area respectively The headlands, nearshore islands, and shoals have an important role in distribution of incident wave energy along Binh Thuan Coast Studied results are useful for design and construction of nearshore structures, and also, for economical, tourism, and environmental protection activities along Binh Thuan Coast This paper is my deep sense of gratitude and respect to Prof Vo Van Lanh (Former Director of Institute of Oceanography) who devoted the whole life for development career of oceanographic sciences in Vietnam; as well as in support and training for younger generation of oceanographic scientists, the author is one among them He gave me independence in carrying out research works and opportunity to grow in the challenging subject of oceanography, an ideal environment that any researcher could ask for Keywords: wave characteristics, monsoon, coastal zone, and headland Ngdy nhan bdi: 23 - 09 - 2009 Nguoi nhan xet: TS Nguyen Ba Xuan significant wave height (Hs), NE monsoon, SW Dia chi: Vien Hai duong hge 37