Tap chi Khoa hoc DHQGH: Cac Khoa hoc Trai dat va Moi truong, Tap 32, SO 3S (216) 9-94 Mot so cac trung bi6n Ong muc. nu& bien yen b6 V* am Pham Van Hu6n* Trteang DO hoc Khoa hoc Tu nhien, DHQGH, 334 guyjn Trai, Ha :6i, Viet am han ngay 8 thang 8 nam 216 Chinh sirs ngay 26 thang 8 nam 216; Chap nhan dang ngay 16 thang 12 nam 216 T6m tit: Bang cac phep phan tich thong ke doi Arai ca sa du lieu muc nuac tai cac tram hai van yen ba Viet am cap nhat tai nam 215 bai viet nay thong bao met so (lac trung bien Tang mix nuac bien nhu xu the clang cila muc nuac trung binh, cac muc nuac tan xuat hiem, cac do lon nuac dang bao cue dai doe ba bien.,thay rang xu the clang muc nuac bien cl9c ba Viet am on dinh trong vai chuc nam gan day, bang khoang 2-3 mminam. Cac muc nuoc thiet ke vai hal lcs/ khac nhau than du9c thong qua xir 1S, bang phuong phap phan tich cue tri chac clan c6 tinh tin cay cao han, c6 gia tri tham khao doi vai ding tac thiet ke xay dung cong trinh ven bien va hai dao. Quy mo cua nuac dang do hoat Ong cua ap thap nhiet dai va bao anh huang chrgc thong ke cho toan dai ba Viet am nam trong giai han 1-3 m. Tie khoa: Phan tich thong ke, xu the, su dang len muc nuac bien, phan tich cuc tri, muc nuac thiet ke, bao va nuac dang bao. 1. Mlr dau Van d ve xu th6 dang len dm mix,nuarc bien quan su ming len toan cau doi vai yen ba Viet am duge giao su guyen g9c Thu)/ [1] de cap lan dau tien va khich le mot so can 13 hai ducmg hoc thuc hien danh gia dinh Luang ye hi'en Wang nay. Lan lugt xuat hien cac thong bao cua Bui, Dinh Khuac, guyen Tai HO, Pham Van Huan [2-4] ye cac ket qua trien khai phan tich xu the dang len dm muc nuerc bien ven ba Viet am dua ten so lieu quan trac muc nu& han the den tiled 16/ cuoi the ki 2. Trong [4],tac gia bai bao nay cling da giai thie'u chi tiet ye phucmg phap phan tich cuc tri, cac khia canh ling dung thuc to cua phucmg phap, ap dung tai lieu khuyen cao va chucmg trinh may tinh cua WMO [5] va dua ra mot so ket * DT.: 84-912116661 Email: pvhuan@viettel.vn 9 qua phan tich cu th6 vai muc dich lam thong tin tham khao cho cong &Ong nghien ciru hai ducmg hoc. Den nay ngu6n du lieu quan trac muc nuac tai cac tram hai van yen ba Viet am da duge bo sung dang ke, them khoang han hai chuc nam quan trac. Tac gia da thuc hi'en phan tich chi tiet ve xu the ding len cua muc nuac bien yen ba Viet am, tinh toan cac muc nuac hiem tai cac tram vai so lieu quaqn trac muc nuac tin cay. Hy vong cac thong tin dua ra ca ich cho nhang nguai nghien cfru va cac nha quy hoach phat trien san xuat yang duyen hai dat nuac. 2. SO lieu IA phirong phi') philn tich Ca sa du lieu dung tong bai viit nay la s6 lieu quan trac muc nuac bien tong gia tai cac tram hai van duge thu thap tai nam 215 tai Trung tam Hai Van, Tong cuc Bien va Hai dao
P.V. Hutin / Tap chi Khoa hoc DHQGH: Ccic Khoa hoc Trai ddt va mem truang, Tap 32, So 3S (216) 9-94 91 Viet am. Thong tin ve cac chuil quan trac dan trong bang 1. Cac gia tri do cao muc nuac quan trac ducic kiem tra ti mi bang cach so sanh vai muc nuac they trieu du tinh de loai trir nhans lei the, daz biet doi vai cac gia tri muc nuac toi cao, toi thap nam., Thong tin ve ap thap nhiet dai va bao duoc lay tir co sa du lieu duong di phan tich cua bao ten trang Web: https://metoc.ndbc.noaa.gov/ JTWC/. Thay rang s6 lieu muc nuac quan trac da duoc be sung dang ke so vai th6i ksi cac tai lieu dan trong ton* quan a phan m6 dau. DO dai cac chuoi quan trac den nay có the xem la dap ung ducfc yeu cau cua cac phan tich thong ke. Ciing vai thiet bi va ky thuat quan trac cua cac tram trong th6i ky gan day chac chin ket qua phan tich se co d6 tin cay hon. Hai phuang phap phan tich sir dung trong bai viet nay la phuang phap phan tich xu the (trend analysis) va phucmg phap phan tich cuc tri (extreme analysis). Phucmgphap phan tich xu the ap dung doi vai cac chuoi thai gian muc nuac bien trung binh nam, ap suat cuc tieu tam bao, toc d6 gib elm dai tam bao... Theo phucmg php nay to nhan duoc,phuong trinh hoi quy eu dien sir tang len tuyen tinh cua tri quan trac vai th6i gian va xac dinh xu the tang trung binh 1 nam. Phucmg phap phan tich cuc tri ap dung vai cac tap gia tri muc nuac toi cao, toi thap nam, xac dinh cac muc nuac cuc tri thiet ke vai h6i ky khac nhau: 2, 5, 1, 2 nam... Bang 1. Thong tin ye se lieu quan trac muc nuac Cac dac thing d6 lan nuac clang bao cue dai tai cac tram ven bien &cm xac dinh bang cach so sanh,d cao muc nuac quan trac do cao they trieu du tinh theo cac b6 hang so dieu hoa thily trieu day du do tac gia to phan tich. 2. Xu the dang len ciia nity ntreic bien yen biy ViOt am Phan tich xu the clang len ciia muc nuac ap dung doi vai ba tram dien hinh cho cac loan b6 Viet am va có lich sir moc do on dinh la Hon Dau, Scm Tra va Vimg Tau. Vi du ve ket qua phan tich xu the,d6i vai muc nuac trung binh nam tram Hon Dau,ducfc the hien tren hinh 1. Bang 2 tong hop ket qua tinh toc do dang (mm/nam) cua muc nuac bien trung binh tai cac tram duoc phan tich. So sanh vai cac thong tin trong cac tai lieu tong quan trong phan ma dau thay rang vai chuoi so lieu dai han ket qua tinh toc do clang len ciia muc nuac bien doc b6 Viet am to ra on dinh. Vi du, vai tram Hon Dau, duoc biet tram nay có lich sir moc do re rang, may quan trac lam vi'ec on dinh, ket qua tinh mai 6 day khi tang so Warn quan trac len 21 nam cho sai khac chi bang,1 mm. Theo [4] vai so lieu quan trac tai nam 1994 xu the clang tai Hon Dau 2,1 mm/nam; San Tra 1,2 mm/nam va Yung Tau 3,2 mm/nam. TT Tram Tea do am quan trac 1 Hon Dau 2 4'-16 49'E 1957-215 (59) 2 Son Tra 16 6'-18 13'E 1978-215 (38) 3 Wing Tau 1 2'-17 4'E 1979-215 (37) Bang 2. Xu the dang len cua cac muc nuac bien tai cac tram yen bar Viet am TT Tram Tca do am quan trac Xu the (mm/nam) 1 Hon Dau 2 4'-16 49'E 1957-215 2, 2 Son Tra 16 6'-18 13'E 1978-215 2,4 3 Viing Tau 1 2'-17 4'E 1979-215 2,8
92 P.V.zian / Tap chi Khoa hoc DHQGH: Ccic Khoa hoc Trai d'dt va Moi trttov, T'etp 32, So 3S (216) 9-94 Cm 25 2 195 19 185 rn ) ) CD 43 a) (-4 co co CO co cr, ) 3 C4 ) (-A Hinh 1. Bien thien muc nuac trung binh nam (duong lien net) va xu the dang len (duong gach n6i) tam Han DAu hu vay c6 the xem cac uac lucmg mai nay tam tin,cay ducfc. roc do clang len dm muc nu& bien a toan dai Y Viet am bang khoang 2-3 mm/nam. Suy ra, den cuoi the ki nay quy me) dang len dm muc nuac en yen ba Viet am bang khoang 2-3 cm, thien thap dang ke so \TIM kich ban nuac bien clang dm BO Tai nguyen va Moi truemg [6]. 3. Ket qui phin tich cac muc nu& tan A.A suet him Muc nay den ke't qua phan tich cuc tri ap dung doi Yeti mot so tram dien hinh cho cac loan ba Viet am Yeti hog dong kinh to soi dong (bang 3). DO dai tap mau cac gia tri t6i thap, t6i cao nam dung xfr 1Si de nhan duac bang 3 khac nhau nhung nhin chung tam dap fing yeu cau thong ke. Vi vay bang lc& qua nay c6 gia tri tham khao tin cay hcm so yen cac thong bao truac day. Bang 3. Cac d6 cao muc nuac thiet ke tai cac tram doc bo Viet am Muc nuac cuc tieu (cm) Muc nuac cuc dai (cm) Hei ky (nam) Hei ky (nam) 2 25 5 1 2 5 2 25 5 1 2 5 Han Dau -4-6 -14-22 -3-4 415 418 43 442 455 473 H6n gu -17-21 -34-48 -62-8 376 38 395 41 425 446 Scm Tra 12 11 7 3-1 -6 237 242 256 271 286 38 Quy han 15 12 2-8 -18-32 278 28 287 293 3 31 ViIng Tau -37-4 -47-55 -63-74 435 437 442 448 454 462
P.V. Hu/2n / Top chi Khoa hoc DHQGH. Ccic Khoa hoc Trezi cat va MOi truing, TO 32, SO 3S (216) 9-94 93 Bang 4. Th6ng ke d8 lan nuac dang cue dai ven b8 Viet am TT Tram Tga. de uoc clang (cm) That gian xuat hien Bao lien quan 1 Co T8 2 58'4746' 163 2-1-1994 34/1994 2 Bai Chay 2 57'47 4' 21 3-6-1992 3/1992 3 Cita Cam 2 46'46 5' 266 12-7-1976 4 Hon Dau 2 4'-16 49' 148 24-7-1996 18/1996 5 Ba Lot 2 19'4 6 31' 24 22-8-1996 18/1996 6 Hon gu 18 48'-15 46' 198 29-8-199 15/199 7 Hoing Tan 19 46'-15 52' 197 16-9-25 16/25 8 Cam hugng 18 15'4 6 6' 127 18-9-25 16/25 (Vicente) 9 Cira Viet 16 53'-17 1' 134 2-1-26 18/26 1 Sam Tra 16 6'-18 13' 158 29-9-29 17/29 (Ketsana) 11 Quy hcm 13 2'-19 15' 174 12-6-1976 12 Ben Luc 1 38'4 6 28' 186 3-3-188 13 Viing Tau 1 2'47 4' 266 8-1-1994 32/1994 14 Phu QuS, 1 3'-18 54' 12 24-2-1991 15 Rach Gia 1 '-15 5' 12 28-11-1978 21/1978 16 Con Dao 8 41'4 6 36' 169 12-6-1995 17 Tnxong Sa 8 39'411 55' 146 9-1-26 4. Thong ke ntrerc dang bao cvc dai doe biy Via am Cac di) Lon nu& dang cvc dai tim &roc tai cac tram ven ber va hai dao Via am &roc sap xep theo tit* ti,r tir ba'c vao nam trong bang 4. uac dang tai tong tram phi thuc vao twang gio mita, tinh huong ap thap nhiet den va bao di chuyen tucmg din so von dining ber va hinh thai vang bien ran On tram quan trac. Thay rang quy mo chung cita mrac clang ven be, nuerc to coy 1-3 m. Co the có nhung dot ntrac dang Ichong lien quan ton hog dong bao. 5. Kk lu#n Da danh gia duoc nhfing dac tnmg thong ke co Sr nghia thuc lien ye sv bien dong cita mvc nuerc bien yen b6 Via am, dua ket qua tinh toan cac do cao thiet ke cita nitre nuerc tai nhieu doan ba. Xu the clang len cna narc nuerc bien yen boa Via am bang khoang 2-3 mm mot nam. DO lem mac dang yen be( Via am nam trong khoang 1-3 m. Co nhang dot nu& clang co the Jchong that thia lien quan tbi anh huong truc tiep cita bao manh. Tai lieu tham khao [1] guyen goc Thuy. Ve xu the nuac bien ding a Viet am. Tap chi Khoa hoc KS, thuat bien, so 1, Ha ei, 1993 [2] Xac djnh them ve xu the muc nuac hien tai met se diem ven 1)6 bien Viet am. Bao cao thuc hien chuyen de do BUi Dinh Khuac thuc hien / De tai [3] cap nha nuac KT-3-3, 1993 guyen Tai Hoi. Report on tidal characteristics (Sub. A5). Design water levels (Sub. A13). Marine Hydrometeorological Centre. Vietnam VA Project, Hanoi, 1995 [4] Pham Van Huan. Extremum sea levels in Vietnam coast. Tap chi khoa hoc DHQGH, T. XIX, o 1, [5] 23, tr. 22-38 Tibor Farago, Richard W. Kats. Extremes and dessign values in climatology. WCAP-14, WMO/TD o 386, World Meteorological Organization, 199. [6] B6 tai nguyen va mai throng. Kjch ban bien dei khi hau bien ding cho Viet am.xb Tai nguyen- M6i trdmg va ban do Vi' am, ph'in 1 212.
94 P. V. Haim / Tgp chi Khoa hoc DHQGH: Ccic Khoa hoc Trai ddt vd Moi truong, TO 32, Seri 3S (216) 9-94 Some Parameters of the Changeability of the Sea Levels along the Vietnam Coast Pham Van Huan VU University of Science 334, guyen Trai, Hanoi, Vietnam Abstract: By the calculations applied to the sea-level observations of oceanographic gauges along Vietnam coast updated onto year of 215 this paper presents some new characteristics of changeability of Vietnam coast sea levels as rising trend of mean, design values of the yearly minimal and maximal levels of different return periods and the ranges of storm surges in Bien Dong sea. The results show a stability of rising trends of sea levels along the coast of Vietnam in last some decades to be of about 2-3 mm per year. The design heights of different return periods obtained by extreme analysis surely have higher accuracy and have reference value to design works of hydrotechnique constructions. Maximal range of storm surge along Vietnam coast is of 1 to 3 m. Keywords: Statistical analyses, trend, sea level rise, extreme analysis, design levels and storm surges.