Tap chi Khoa hpc va Cdng nghg Bign; Tap 16, Sd 4; 2016: 373-380 DOI: 10.15625 1859-3097/16/4/7554
. h^V/www.yjs.ac.vn/mdex.php/jmst
MOT SO NHAN DINH BAN D A U VE HIEN TUONG SONG N O I XAY RA 6 VUNG BIEN MIEN TRUNG VIET NAM
nag Phudc H o i i « Som', Trin Van Chung, N g m i n Hun Huan, Ngo Manh Tiin Vien Hdi duang h^- Vien Han Idm Khoa hoc vd Cong nghe r,et Nam
E-mail: tong)huoehoangson@gmaiLcom Ngiy nhan bii: 21-12-2015
• ^^ ! ^ .-*"?* '^' "°^^ "^'^ "*" '••f" «' *'«" ^"g vd da duoc cdc hpc gid nude ngodi xac dinh chu yeu dua tren tu lieu dnh RADAR Bdng su dung ngudn dnh viin thdm da phi. da nguon. da thm gmn bao gam cd c&: dnh vien thdm da phd VNREDSAT-l (do Viet Nam bm- chyp) thuthgp trong then gian gdn ddy. Idn ddu lien dd nhgn dang hien tupng sdng ndi d Biin Ddng b£,g nr /,f„ a„A da pha cung nhu phat hien ra quy luat hinh thanh sdng npi d vung biin miin Trung Vi^t p. Nam. Ket qua phan nch cho thay. hien nrpng sdng ngi xuit hien d vimg biin miin Trung Viet Nam
tim? T ^ """..Tft ^^' ^ - ^ C^ "^ * * " "^S 9 hang nam) vd ndm d ven ria cua them luc dia. Songng, h,r,h thanh dpc theo vimg bien mien Tnmg Viel Nam chu yiu Id cdc tin hieu duvcsmh ram vung them bdi cdc sdng Idn, xuyen qua luu vuc tu eo biin Luzon. Kit qua nghien cm, da phat h,fn ra mpt khia cgnh Ung dung khdc cua dnh viin thdm VNREDSA T-l trong ITrO, vuc ha, duong hpc no, Chung vd nghien cuu chi tiit sdng noi ndi rieng
Tir khda: Sdng npi. VNREDSAT-l. dnh da phd. dnh viin thdm mdu hdi duang
MO DAU
Sdng npi diudng xuyen xuit hign frong Bign Ddng, tu nam 1970, inh vg tinh da cung cip mpt cdng cy higu qui d i phit hign cic sdng npi t^i phia bic Biin Ddng [)]. Theo cic hmh inh vg tinh va dir ligu quan trie hign tnidng [2- 5], eo bien Luzon li m9t ngudn thinh tao chinh cho sdng npi d phia bac Biin Ddng. Theo kit qui phan tich ciia Li vi nnk., (2011) [6], mpt so sdng npi d ddng bic Biin Ddng da dupe nhan d|ng tu inh vg tinh. Kit qui niy cho diiy sv can thigt dg xem xgt toin bp anh hudng ciia sdng npi trong viing bign Nam Trung Bp tir bp inh NAREDSAT-l sin cd. Thdng tiiudng, cic song n9i cd thi xiy ra trong suit c i nam d phia bic Bign £)diig [7], nhung tdn t^i bien ddi dieo miia rd rgt. Tin suit xuit hign cic sdng npi cao nhit thudng xiy ra li vio tiling siu - diing biy, vi tan suit xay ra diip nhit li trwig tiling gigng - tiling hai [5]. Global Ocean Associates
da kgt luin rang sdng npi d Biin Ddng xiy ra frong ba khu vvc: (a) giira eo biin Luzon vi dio Hii Nam; (b) dpc dieo bd biin Vigt Nam;
va (c) giiia Vigt Nam ra Borneo [8]. Tm higu sdng npi dpc dieo bd biin Vigt Nam dupe phit hign dudi ba dang sau: (a) tin higu dupe sinh ra tai viing tiigm bdi cac sdng Idn, xuygn qua luu vvc tu eo bign Luzon; (b) tin h i ^ ciia mpt tiirdng sdng npi "khdng xic djnh"
(disorganized intranal wave field); vi (c) tm higu cua ^ n g npi dupe tao ra tai cic ddi dirt gay ciia them Ipc dja bdi triiu [6].
Trong nam 2014, vdi bp inh vien thim VNREDSAT-l phvc vu cho de tii cap nhi nude "Xdy dung ca sd da li^u sd cdc yeu to hdi duang tir nguon dnh VNREDSat-l vd cdc dnh vien thdm khdc cho khu vuc ven bien Ninh Thudn - Binh Thuan phuc vu phat triin kinh te bien ben vOng md sd: VT/UD-07/14-15", trong qua trinh phan tich, nhdm tic gii da phit hign
373
Tdng Phudc Hoang San. Trdn Van Chung, ...
diu vit ctia smg npi xuit hign d vimg bign ven bd mign Trung. Phii chang, day li mpt hien tupng mang tinh quy luat, xuat hign thudng xuygn d khu vvc nay? Qu\ md, pham vi. thdi gian hinh thinh ciia chung d viing bign ven bd Viet Nam ra sao? Thdng qua phan tich inh viin thim quang hpc, can cu vio cic kgt qui nghign cuu trudc dd cua cic tie gii nude ngoii (Li vi nnk., (2011) [6] vi Cai va nnk., (2014) [7]), nhdm tic gia di dua ra mpt sd nhan djnh ye hien tupng sdng ndi viing bign ven bd mien Trung Vi^ Nara
TAI LIfU \ A PHirONG PHAP Tii lif u
Anh vign thim quang hoc dp phan giii cao:
VNREDSAT-l. SPOT5 (10 m), ALOS- AVNIR2 (10 m), Fomiosat-2 (8 m), Landsat TM vi Landsat ETM+ (30 m) hign dang luu tiii d Vign Hii duong hpc, nhim nhan d^ng diu vgt cua hign tupng sdng npi xiy ra d vung biin ven bd Vigt Nam.
Anh vien tham miu hai duong: Cic aid) MODIS Aqua va MODIS Tena 250 m, dupe chup hang ngiy d viing bien miin Trung tir traa
web ciia NASA httpsy/eardidata.nasa.gov/data/near-real-time-
data/rapid-response/modisrsubsels nhim xic ^ cac diu vit cua sdng n^L Tuy nhign, thvc ti, dj cd cac inh MODIS bj anh hudng bdi bdng nii^
(sun gUnt) mdi sir dvng tdt cho myc dich niy.
Phirang p h i p nghign ciru
Giii doin bing mit (visual interpretation) dva frgn inh vien thim quang h9c vi inh viin tiiim miu hii duang: Cac diu vgt ciia sdng ngi cd thg nhan d^ng ti^c ti^) fren anh vien tfiam cd dp phan giii cao va sd hda hvc tiep fren man hinh. Ket qui nghign ciru cua Uy ban Hai duomg toin cau Hii quan My ve sdng npi frong Biin Ddng, cho tiiay sdng npi frong Biin Ddng cd kich thudc khi Idn, chiing hinh thinh hjng nhdm, keo dii hing fram km vdi birdc sdng Ign din hang chvc km (hmh 1).
"'""(Ji N i ^ ' i t h ^ f r T ^ Z ''"^'.''*^" ^ ^ " S ^ ' ^ " ^ ° " g (') Eo Luzon, (2) Nam dio Hii Nam, (3) Ngoai khai (Juang Nam va (4) Ngoii ^ a i Quy Nhan (tham khio hi Atlas sdng npi
cua Uy ban Hai duong toin cau - Hii quan My nam 2004) 1. ' ; 1 ^ ; J o ' ^ ^ '^"^ ^^ Pl^" giai tnmg bmh
nhu MOpiS, SEWIFs, MERIS chvp hang ngiy dM khi cung cd dig nhin d?ng dupe diu vit cua sdng npi. Tuy nhign chi cd cic cinh inh viin tham b| anh hudng ciia bdng ning (sun glint),
cic diu vgt cua sdng npi miM thi hign rd ndt Mpt manh cit vting ven biin Khinh Hda - Ninh Thuan tii inh MODIS Aqua chup ngiy 27 thing 8^ nam 2008, cho thay cic diu vit cua sdng npi ip ra dudi anh hudng cua bdng ning (hinh 2).
Mot sd nhgn £nh ban ddu ve hien tuang sdng .
I
Hinh 2. Diu vet cua sdng ndi dig hign rd trgn inh MODIS Aqua bj bdng nang chup ngiy 27 diing 8 nam 2008 QUA NGHIEN CCVCac diu vet sdng npi or viiiig ven biin Ninh Tbu|n tir anh VNREDSATl
Tir hai bp inh VNREDSAT-l, mpt chup vio ngiy 4 tiling 9 nam 2013 (3 cinh) va mpt
bd khic chup vao ngiy 23 tiling 8 nam 2014 (5 cinh) d vung yen bd Nmh Thuan, chiing ldi nhan thay diu vit cua sdng ndi xuit hign ttgn ca hai bp anh niy. Quy md vi vj tri cua cic bp sdng npi niy dupe dig hign rd ttgn hinh 3.
Hinh 3. Diu vit cua sdi^ npi, xuit hign vAo ngiy 4 9 2013 (ttii) va 23 8 2014 (phii) tten cac bp anh VNREDSAT-l d vung bign Ninh Thuan
375
Tong Phudc Hoang San, Trdn Van Chung, ...
Nhan dang hifn tirgrng sdng n?! d khu vyc mien Trung Vift Nam. tir anh viin thim da nguon, da thdi gian
Cic kit qui viia phan tich d trgn la mot vii kit qui xuit hign ngiu nhign, hay day li mpt hign tupng mang tinh quy luit, xuit hign
m
thudng xuyeii^d khu vyc? Bing vi?c t?p hpp xu ly cic inh viin thim da thdi gian, da cho phgp lim sing td hom tinh tdn t^i thudng xuygn cia hien tupng niy vio miia gid Tay Naia Hii^
loat hue inh thg hign sv tdn t^i cua sdng n^
vio miia gid Tay Nam chi ra d hinh 4, 5.
Hmh 4. Dau v« ci^song „p, „ „go4, kh„i Hug - Di ning (trgn - ttii), Quing Ngai - Binh Djnh vin R?/fi^^A" ?""'^i" ^"^ SW Radar JERS1. Sdng npi d m i ^ Tning vio 8/2008 (duoi - ttii) vi 8/2014 (dudi phii) tir irA MODIS Aqua
m
I 1101 itic
.\fd, so nhan ibih ban ddu ve hien tuang sdng.
®f g\
Song noi 6 ngoai khOf Nha Trang Song no: 6 cua vmh Cam Ranh va^thang 7,'2004 til anh LS ETM+ vao thang 7 2014 tit anh _andsat , Hinh 5. Sdng "pi xd.hign d v i i ^ biin ven bd miin Tnmg tir cic loai inh viin thim
khac nhau co dp phan giai cao, tiidi gian chup khic nhau Cac phan tich bin da cho Uiay diu vk ciia
sv xuit h i ^ sdng npi, cd net niong ddng dupe phit hign trong cdng tiinh cdng bd ciia Li onk.
(2011) [6] thg hign bdn hmh 6, inh ASTER false-color VNIR (60 80 km) doc theo bd bien ciia Vigt Nam da diu dupe vio neiv ''9 diing 7. 2001.
Tir cac kit ^ phan tich vi tap hpp tren 100 biic ixb vien Aim chyp tir cic thdi ky khic nhau. ngudn inh khic nhau da cho thiy, hign tiipng sdng npi xuat hign d viing biin mign
TiUBg Vigt Nam. chu ygu xuit hign vio mua gio -ray Nam (tii tiling 6 din tiling 9 hing ram) va nam d ven ria cua diim luc dia (hinh 7).
Va" nwa gio Bong Bic chu yiu vio tiidi ky chuyen tiqj, hign ttipng sdng npi cimg xiy ra nhung vdi quy md nhd va rdi rac.
Cic kit qui nghign cuu cua chiing tdi dig hi?n tren Mnh 8 khi tning vdi kit qui cdng bd ciia Wang va nnk., (2012) [9].
377
Tong Phudc Hoang San. Trdn Van Chung.
Hinh 6. Anh ASTER felse-color VNIR (60 x 80 km) dpc theo bd bign cua Vigt Nam da thu
dupe vio Idc 10 h 3 r ngiy 29/7/2001
V /
04 NSng Qudng Nam
QD Hoang Sa
Quang Ngai U 1
Binh Dinh ), PhiiY«n W
Hinh 7. Diu vet ciia hign tupng sdng npi d vimg bign mien Ttung xiy ra chu yiu vio miia gid TN. duijic nhin d^ng dva ttgn 150 inh vien thim
CO ngudn khic nhau, thdi gian chup khic nhau
Hinh 8. Phan bd sdng npi frong Bien Ddng tir anh vg tinh (Wang va imk., 2012) NHAN X ^ T VA THAO LUAN
Tir kgt qui phan tich cho thay:
Ton tai mpt khdi nude min, l?nh nim ven bign Khinh Hda. Khdi nude niy cd le hinh thinh do Ivc nang ciia sdng npi dang (elevation wave) dua ngudn nude lanh, man tir dudi sau Ign vi truygn vio bd.
Ben c?inh khdi nude niy, xuit hign mgt khdi nude khic nhat hon, i m hon ddi chut. N6 nam triing vdi bien cua ddng chiy chinh hudng SW-NE tir mat xudng diy. Cd the gii thuyet nhu sau "ddng chiy khi van chuygn dpc bien lim ha nhigt dp vung nude giip bien, lam thay ddi cau tnic nhigt theo chigu thing dimg vi hinh thinh nen Idp dpt biin nhigt dp" Chinh Idp dpt bien nhigt dp niy, din lupt nd l^i t?o nang lupng de hinh thinh cic sdng chitn (depression wave) ngay d Idp bign, nd truyen vio bd vi hinh thinh nen cic sdng dang. Yiu td dja hinh d sudn doc ciia thim lye dja nim triing vdi khdi nude niy li yiu to phv b i trg cho sv hinh thinh vi phit trign ciia sdng npi a khu vuc.
Cic kgt qui tir md hinh hda ciing chi ra sv hinh thinh cic cot xoiy diuan kich dnrdc Idn nim d phia bac aia khu vuc (tiic ngoii khoi Quing Nam - Bmh Djnh). Cd thi cho ring, cic kigu sdng npi khic cung hinh thinh d viing ven bd Binh Djnh - Phu Ygn vdi ca chi tuong tv- Anh vien tham Landsat ETM-i- chup vio tiling 7 nam 2003 ciing da xic djnh dupe cac diu v a ciia sdng ndi xiy ra d vung yen bd Phu Ygn vi khang djnh Hon tinh diing din ciia gii thuyit vi sv hinh thinh sdng npi frong mdi lien quan vdi sv xuit hign cic tam cao cua chlorophyll-a d viing ven bd Khinh Hda.
Thdng qua phit hign nglu nhign vi diu vit ciia sdng npi d vung biin miin Trung tir cic bd inh V>«IEDSAT-1, chiing tdi da cd tim higu budc dau nghign cim phin bo sdng npi cho vung bign Nam Tnmg Bd. Thdng qua tir ligu vien tham da ngudn, da tiidi gian, da xac dinh duoji sdng npi d vimg biin miin Tnmg, hinh t | W vi xuat phit d vimg ria cua tiiem Ivc dia v i | ^ t hign chu ygu frong miia gid Tay Nam.
f Ldi cim om: Tap thi tac gia xin chin thinh I cim on Ban chu nhigm Chuong ttinh cip nhi
nude vg Khoa hpc vi Cdng nghf Vu tiii, TS.
Nguyen Him Huin - chu nhigm de cap cip nhi nude: "Xdy dung ca sd du lieu .so cdc veu to hdi duang tir nguon dnh VNREDSat-I vd cdc dnh vien thdm khdc cho khu vuc ven hien Ninh Thugn - Binh Thugn phuc vu phdt triin kinh te bien ben vOng", md so: lT/UD-07/14-15 da tai trp kinh phi va dpng vign tinh thin trong qui frinh trign khai npi dung nghign cim. Cim on dong nghigp d Vign Hai duang hpc vi nhirng ddng gdp quy gii di hoin thinh bii bio niy.
TAI LIfU THAM KHAO
1. Felt, R, and Robe, K., 1977. SatelUte observation of internal wave refraction in the South China Sea (Bien Dong). Geophysical Research Letters, 4(5): 189-191.
2. Ehhesmeyer, C. C, Coomes, C. A..
Hamilton, R. C, Kumci. K. A., Sullivan, T C, Salem, B. L., Romea, R D., and Bauer.
Mgt so nhan ^nh ban ddu ve hien tuang song ...
R. J., 1991. New observations on intomal waves (soUtons) in the South China Sea (Bien Dong) using an acoustic Doppler current profile. Marine Technology Society 91 Proceedings, 165-175.
3. Liu, A. K., Ramp. S. R. Zhao, Y., and Tang, T. Y.. 2004. A case study of intamal solitary wave propagation during ASIAEX 2001.
IEEE Journal of Oceanic Engineering 29(4): 1144-1156.
4. Ramp, S. R, Tang T. Y., Duda, T. F., Lynch, J. F, Liu. A. K., Chiu, C. S.. Bahr, F. L. Kim, H. R, and Yang. Y J. (2004).
Internal solitons in the northeastern South China Sea (Bien Dong). Part I: Sources and deep water propagation. IEEE Journal of Oceanic Engineaing, 29(4): 1157-1181.
5. Zheng, Q.. Susanto. R. D.. Ho, C. R, Song, Y. T., and Xu. Q., 2007. Statistical and dynamical analyses of generation mechanisms of solitary internal waves in die northern South China Sea (Bien Dong).
Journal of Geophysical Research: Oceans 112(C3).
6. Li. D.. Chen. X. and Liu. A.. 2011. On the generation and evolution of internal solitary waves in the northwestern South China Sea (Bien Dong). Ocean Modelling 40(2): 105-119.
7. Cai. S., Xie, J., Xu, J.. Wang D, Chen. Z, Derig. X. and Long. ,V., 2014. Monthly variation of some parameters about internal solitary waves in the South China Sea (Bien Dong). Deep Sea Research Part I:
Oceanographic Research Papers, 84, 73-85.
8. Global Ocean Associates. 2004.
hnp://www.intemalwaveatlas.com.
9. Wang J.. Huang W., Yang J., Zhang H, and Zheng G., 2013. Shidy of the propagation direction of the internal waves in tiie South China Sea (Bien Dong) using satellite images. Acta Oceanologica Sinica 32(5): 42-50.
379
Tong Phudc Hodng San, Tran Van Chung, ...
SOME INITIAL DISCUSSIONS ON PHENOMENON OF INTERNAL WAVE IN COASTAL WATERS OF CENTRAL VIETNAM
Tong Phuoc Hoai% Son, Tran Van Chung, Nguyen Huu Huan, Ngo Manh Tien Institute ofOceanography-VAST
ABSTRACT: Internal waves often occur in the East Vietnam Sea and have been determined mainly based on RADAR images. By means ofdataset of VNREDSAT-l satellite images and other imagery sources, for the first time, internal waves in the East Vietnam Sea have been identified by multispeclral images: Also the formation mechanism of internal wave in the nearshore Haters of Central Vietnam has been found The analytical results show that the phenomenon of internal MH\e occurs in the nearshore waters of Central Viemam mainly in the Southwest monsoon season (from June to September every year) and is located along the edge of the continental shelf. Internal HHIW formed along the waters of Central Vietnam mainly include the signals that have been generated at
the shelf by large waves, through the basin from Luzon Strait. The study results have discovered a new applied aspect of VNREDSAT-I satellite irrmges in oceanographic research in general and detailed studies on internal naves in particular.
Keywords: Internal Have. VNREDSAT-I, multispeclral image, satellite ocean color imagery.
