AN TOAN GIAO THONG A n ninh hang h ^ l
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TS,TTr.LEVANTY Oai hoc GTVTTP. Hd Chi Minh
Khd cd the quen difdc can bdo so 5 kinh hodng ndm 1998 dd Idm chit vd mdt tich tren 300 ngifddn mien Trung vd Nam Nam bp - Mpt thdm hga khong ddng cd liic bay gid; vd nhifng can bdo cudi miia hiem cd, vdi cififng dp Idn, dd dp vdo mien Trung vd phia Nam nifdc ta trong ndm 2006, gdy thiet hgi Idn ve con ngifdi vd tdi sdn. Nguyen nhdn chinh Id sU thieu hieu biet vd chii quan ve bdo nhiet ddi cua ngifdi ddn song trong viing von difgc coi Id thien nhien Ifu dai bon miia.
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hi nghien cffu ve bio nhiet dpi ngddi ta thay ring, de hinh thinh mdt xoly thuan (vung CO khdi khdng khi nhieu loan, ed ap suit thap ban so vdi binh thudng, cd gio xoly v l gilt dudi cap 8, tffc II nhd han 80km/h) hoac bao nhiet ddi (xoly thuan tren vung nhiet ddi co sffc gio Idn hdn d p 8), d n ed d e dieu kien sau:- Cd mpt khdi khdng khi tren bien bi nhieu loan
- Khdi khdng khi phii eo dp am du ldn (vi vay bao ehi hinh thanh tren bien rdi mdi di ehuyen vIo dl't lien)
- Nhiet dp nddc bien Idn hdn 26°C.
Oieu kien nay tddng ffng vdi quy luat di chuyen cua mat trdi tff Nam ban eau len Bic b i n d u tff sau ngly 21/3 hing nam. Mat trdi sudi I m d c vung bien trong sudt thdi gian nam lai vung Ble b i n cau. Cle can bio nhiet ddi eung b i t d i u xuat hien d vung bien phia Bic, sau dd chuyen d i n ve phia Nam. Viet Nam n i m holn toan trong vung khi hau
nhiet ddi. Vung cffc nddc ta (Cdn Oao) d vao khoang 8° vl tuyen Ble v l ede Ble (Quing Ninh) d vao khoang 22° vT tuyen Ble, vl vay mua bao nude ta thudng b i t dau tff thing 6 v l ket thue vIo thing 12 hang n i m . Thing 10 I m Ijch ddpe coi II thing ket thue mua bao d vung bien 06 Sdn, HIi Phong. Ngddi dan phdong Nam thddng chffng kien nhffng can bao mudn tff sau khoing thdi gian nay.
Tuy nhien, do nhffng bien dpng b i t thUdng cua khi hau (hien tdpng EInino), nhiet dp nddc bien van eao trong mua thu-dpng d vung Ble b i n clu, khIe vdi quy luat hing n i m di ehuyen eua mat trdi. Tff do thl'y ring d c can b i o manh van hinh thinh lien tue trong d e thing 11, 12/2006 va van di ehuyen len vung bien Ble hole di theo nhffng quy dao b i t thddng (Bio sd 8, 9, 10/2006).
- Bao chi hinh thinh d vung bien ed VI dp dja ly Idn han 5° (Ble hole Nam).
Gio xoay tao thanh bio la do viee di chuyen eua ddng khong khi tff vdng ngoli vao trung tam ed ap suit thap, tao thanh xoly va bde len eao g i y mda dff dpi, sdng bien dde va hon ddn. Gid gilt vffa CO sffc xo theo phuang n i m ngang vffa hut len eao lam eho mpi vat nhu bj nhd len khoi mat dat va vang ra xa.
Gid bao khdng di theo dUdng thing tff ngoli vao t i m bao ma lien ttJc bj tie dpng cua Iffc l i m lech hddng. Ldc nly xul't hien khi eo mdt vat chuyen ddng tren be mat dl't, tff do quy dao chuyen dpng lien ttJc bj lech sang ben phii hddng di chuyen (d Ble b i n cau) v l lech sang trai khi d Nam b i n eau (Iffc dd II Iffc Coriolit (C), eong thffc ve dp Idn: C = 2(jj.vsincp). Trong dd, v: tdc dp di ehuyen eua phan tff ehuyen ddng; (p: vi dp dja ly;
OJ: toe dp quay cua trii dit.
Neu gia trj vi dp nhd thi luc C khdng du ldn de giy lech hddng ehuyen ddng
eua cac phan tff khdng khi, hay noi mpt each khac II se khdng cd gid xoly (khdng cd bao hole ap thap nhiet ddi).
Oieu dd giai thich vl sao eae tinh phia Nam nude ta (d vl dp thap) it khi cd bao.
Theo quy luat tren, cac can bao sau khi hinh thanh tren vung bien Tly Thai Binh dddng ludn cd xu hddng di chuyen theo hudng Tly-Tly Ble. Tuy nhien, theo thdng ke, quy luat dd ehi chie'm khoing 30%, sd cdn lai chuyen dpng theo nhffng dddng di khdng quy lull, vi the viec dff doan eua eac n h i khi tupng khd ehinh xle tuyet ddi. Oly la mdi hiem hpa dang thach thffc khoa hpc dff bio va de dpa cudc sdng eon ngffdi. Sau khi do bd vIo dat lien, bao bj Iffc ma sit gay d n trd hole khi di chuyen len vung bien lanh han nang lupng cua chung se gilm xudng, b i o suy yeu v l tan nhanh.
Bio hinh thanh, di ehuyen tren bien vdi nhieu dieu kien thuan Ipi se tich luy them nang lupng v l Idn dan len. Cle con bao manh thudng xul't hien tren vung bien Thii Binh duong, sau khi trin qua Philippines d l du Idn v l di vao nUde ta.
Cdn ele xoay thuan xuat hien tren bien Odng (giffa Philippines vIViet Nam), sau do vIo Viet Nam thddng II d c I p thap nhiet ddi, vi thdi gian ton tai tren bien ngin. Mdt edn b i o tren vung bien Thai Binh dddng keo d i i Iff vai ngly de'n vai chuc ngly.
Hinh 1 la anh chijp ve tinh v l clu true theo chieu ngang cua mdl can bio.
Trong hang hIi, ngddi ta phin chia vung bao thinh cle khu vffc mdt d e h tddng ddi tren ed sd anh hddng eua gid, sdng bien v l khi ning tau thuyen bj cudn vao t i m xoly khi phii chdng chpi tren bien d nhffng vj tri khae nhau. Bio dUpc chia thinh 2 phan qua dddng di ehuyen.
Phin nffa ben phii dddng di ehuyen d Ble b i n eau ddpe gpi la ban vdng nguy hiem (BVNH), vl nhffng ly do sau:
5 8 - Tapchi HdnghdiVietNam • 5/2011
bao thi sdng gid d khu vffc ben phii (BVNH) Idn hdn d b i n vong ben trii.
-Tau thuyen phii chay v i t sdng (eho gio thdi vao phia trude, man phai eua tau thuyen) de vUpt ra sau trung tam cua bao. Viee chay tau vat song se rl't cffc nhpc v l nguy hiem (Vj tri A). Tau thuyen khdng dupe phep chay xuoi gid trong khu vffc nay, vi se bj cudn vao tam bao.
- Neu t l u thuyen khdng du sffc vUpt ra sau bao thi rat de bj dUa vIo t i m , trong lue dd bao ludn cd xu hudng di chuyen lech phai, vi vay khi nang t l u bj dua gan vao t i m bio se ra't Idn.
d Ble ban d u , b i n vdng ben trii dudng di chuyen eua bio dugc gpi II ban vdng hang hIi (BVHH), it nguy hiem hdn, VI:
- Cung khoing d e h den tam bio thi song gio ye'u hon
- Quy tie trinh bio trong vung nly II eho t l u chay chech giP man trai (gid luon thdi vao man trai, phia sau). Lue nay toe dp t l u thuyen tang nhanh, t l u chay eung khde hon, nhanh chong rPi khoi khu vffc nguy hiem; khi nang roi vao tam bao it ban (vj tri B).
Thffc te, neu vj tri t l u d e h t i m bio tUdng ddi xa v l d g i n tren dddng di chuyen cua no (vj tri C) thi ngddi dieu khien l l u thuyen xem xet khi nang thffc hien va cho t l u elt dddng di de
AN TOAN GIAO THONG
A n ninh h a n g h 9
BAN VONG HANG HAI
Hinh 1 Hinh anh khu virc bao va vi tri tau trong bao
chay sang BVHH. Oieu can thiet phii can nhlc la khi bao cang den gan thi toe dp tau d n g gilm xuong, hon nffa sai sd ve dff bio dddng di ehuyen eua bao II khi Idn, neu khPng chle chin thi khong ddpe mao hiem thffc hien.
Viec dieu dpng tau thanh cong trong vung bao phu thude vao khi nang ky thuat cua tau thuyen, sffc khoe eua ngudi di bien, kinh nghiem eung nhU sff hieu biet eua hp ve bao. Mdt trong nhffng nguyen tie da dupe long ke't nham giup eho nhffng nguoi dieu khien tau thuyen tholt nan khi bj rai vIo khu vuc BVNH la Quy tie 3 phii (Phii - Phii - Phii). Neu dffng quay mat ve hudng gio thoi, sau mpt thdi gian thiy hddng gio ddi chieu dan sang ben phii, lue do tau dang nim d bin vong ben phii (BVNH), ludn de gio vat phai de dieu dpng tau dan ve phia sau can bao.
Viec nhan bie't vj tri hien tai cua tam bao het sffc quan trpng va eo the thong qua d c bin tin thong bao thdi tiet, sau dd xlc djnh vj tri tddng quan cua tau minh so vdi t i m bao de cd phddng I n chay tau eho phu hpp. Tuy nhien, khi d tren bien neu ehung ta khong nhan dugc thong tin, thi kinh nghiem quan sat cd the cho ta nhffng phan doln tuong doi chinh xlc hUong den tam bao, bao gdm quan sat hudng di chuyen ciia mIy, hudng eua song Iffng hole sUthay ddi cua ap suit khong khi va hudng giP trong qua trinh quan sat.
- Khi cPn d e h xa t i m bao, nhin len blu trPi thay may miu trIng tren eao nhu nhffng spi khoi thuoe bj hut ve mpt diem (hddng den tam bao).
- Hddng tff do song lung dau tron di chuyen tdi la hddng den tam bao. Chu ky sdng d n g dai thi sffc gid trong tam bao eIng Idn (vi du, neu do dugc chu ky sPng la 10 giiy thi tddng dng gio vung tam bao g i n tdi d p 10).
- Khi I p gilm d i n la bao dang den gan.
- Offng quay m i l ve hudng gio: tam bio se 6 phia tay phii, chech ve sau.
Xet den sff di chuyen b i t thudng cua nhffng cdn bao cuoi mua d nddc ta va sff nguy hiem cua ehung eho tau thuyen, cho cd d i n phia Nam, thay rang:
+ Cac cdn bao cuoi mua thddng xuit hien d vung ed vi dp thip, lUc Coriolit khdng du ldn de dda c l khu vffc bio len phia Ble.
+ Cic khoi khdng khi lanh xuit hien v l di chuyen xudng phia Nam se ep vung bio xudng phia dudi.
H-2 Dau hieu may khi co b3o xa
H 3 Chay vat song de vu-ot bao o B\7TO
+ Khi bao vao g i n vung bd, dja hinh cung la nguyen nhan lim cho quy dao nhieu eon bao ehuyen hUdng dpc theo bP bien xuong phia Nam.
-i-Viec dff bao dddng dieiJa bao trong d c trdPng hpp nay se gap kho khan va khong chinh xle.
Vl bao it khi xuit hien d khu vffc phia Nam nude ta (tff vi dp 12 trd xuong) cho nen nhin dan sdng trong nhffng vung nay rit ehu quan. Nhi cffa eho den ele eong trinh dan dting khIe deu dupe xay dffng m l khong tinh den khi nang chju bao gio.Tau thuyen boat dpng tren bien cung thieu d e thiet bj thong tin lien lac, trang bj an toan, tham ehi ngU d i n con me tin va tin rang viee mang theo phao cffu sinh tren tau se xui xeo. Cle tau thuyen dinh bit tren bien thuPng nhd, cong suit mIy yeu, thieu dff trff d n thiet, dae biet khdng co kinh nghiem dieu khien tau khi gap bao. Viee dUa tau thuyen ve neo tai CPn DIo hole co gIng chay ve ben trong con bio so 5 nam 1998 da lam chet va mat tich tren 300 ngudi, hu hong nhieu tau thuyen la mpt minh chffng dau IPng, du ring sffc gid trong con bao do chi dat d p 8, 9.
Tren thffc te, theo quy l u l l ehuyen dpng va Inh hddng cua khu vde bio thi nhffng tau thuyen tren bien d d c vi tuyen 12 trd xuong rat de phong tranh, nhat la khi hp cP dupe thong tin ve vj tri tam bao, khu vUe Inh hUdng eua gio manh (tren d p 5), va tau thuyen CO ke hoach dff trff nUdc ngpt, Iddng thuc, nhien lieu trong mua bao. Cle tau thuyen 6 khu vUc nay chi can chay xuong phia Nam, hoac theo huong Odng Nam de tranh xa t i m bao se dddc
(Xem tiep trang 43) Tapchi HdnghdiVietNam • 5/2011 - 5 9
LUAT PHAP
Idi cau nguyen cho chiec nhan cudi, chuyen cho chu re de deo vao ngdn thff tff cho cd dau. Ngay sau dd, qudc vUdng - hoang hau tUdng lai cua nddc Anh cung quy trddc b i n te trong sff chuc phuc cua Tong giam mue. Tiep theo la phat bieu cua nhffng vj chffc sic t d n giao chu tri budi le. Khach mdi trong Tu vien cung d i n d d n g ca va dan nhac h i t t h i n h ca v l nhffng bai h i t dUpc soan rieng chao mffng le eUdi.
Sau d d khoang mdt gid (lue 18 g i d 12 phut, gid H I Ndi) la k h o l n h khIc cd dau ehu re bUde ra ngoai trong tieng hP reo cua d i n chung, len eo xe ngffa mui Iran CO, b i t dau le rdde n h d trong chuyen cd tich iffTu vien Westminster ve Cung dien Buckingham, vdi dpi ky binh hp l o n g v l sff vay chao ndng nhiet eua dan ehung hai ben dUdng. Bdn cd xe ngffa khac trong d o l n rdde lan Idpt chd phu dau phu re, nff hoang v l phu q u I n cung cha me cua co dau v l ehu re. Hd tdng doan rdde la dpi ky binh, vdi Id trinh tffTu vien Westminster ve Cung dien Buckingham.
Cle vj khach mdi dff tiec cddi khac tdi Cung dien Buckingham di sau eung tren nhffng chiec hdi va xe buyt sang trpng.
Lue 19 gid 25 phut (gid Ha Npi), cd dau, chu re, Nff hoang Elizabeth II v l d c t h i n h vien trong gia dmh h o I n g gia, xua't hien tren ban eong. Nhffng ngddi than trong gia dmh eo dau eCing cd mat tai day.
Hinh I n h d i e biet ddpe m o n g dpi nha't da dien ra khi ehu re William trao cho CO d i u mpt nu hdn trddc sff chffng kien eua bien ngddi phia dUdi Cung dien v l k h o i n g 2 ty ngUdi theo ddi qua truyen hinh. NgUdi ta d cUpc vPi nhau la hoIng tff se hdn vp v I o dau: v I o moi, vao ma hay vao tai: "For the iconic kiss on the Buckingham Palace bacony, the prince is 1-5 to catch his new wife on the lips, 4-1 on the cheek, and 33-1 to miss and get her ear" ("Bangkok Post", 25/4/2011).
Bay chiec may bay chien d i u bay trinh dien qua phia tren Cung dien luc 19 gid 30 phut (gid H I Ndi) ngay sau do da khep lai nhffng nghi le ehinh thffc cua dam cddi h o I n g gia giffa mdt hoang tff va "mdt thdn nff tff mien que h^o lanh eua nude Anh" ("an ordinary girl from a sleepy English village", Bangkok Post, 26/4/2011) - ngudi da t r d thanh Nff cong tudc Cambridge va cd the I I Nff hoang Anh trong tffdng lai)>J>
N G O K H A C L i , Vietfracht
H a n g n a i
Hiem hoa Xii nhufng corn bao...
yv'*(Tiep theo trang 59)
an toan (Hinh 4), sau d d lien lac ve dl't lien de nhd phoi hpp trp giup sau khi bao tan. Viec co g I n g chay vao b d se nguy hiem vi tdc dp di ehuyen cua bao k h o i n g 10-15 hai ly/gid, trong khi toe dp t l u thuyen d i n h b i t ehi 4 - 5 h I i ly/gid, nen b i o se nhanh chdng duoi kip t l u thuyen. Khi cd bao, nhffng tau thuyen chay ve b d se bj ngupc gio (gio Tay-Tly Nam), toe dp se g i l m manh.
Sdng bien do bao gay ra I I sff ket hpp cua sdng do gio va sdng Iffng, cpng vPi yeu t d mffc nUdc dang vi ap s u i t khong khi t h i p hon binh thuPng.
Khi v I o b d sdng se Iran len, cuon troi h o l e nhan chim mpi vat tren dddng di eua nd. T l u , thuyen nho hoat dpng gan bd, khi nhan dugc tin b i o bao e i n khan trUOng vao b d de neo dau.
Gio trong vung b i o doi chieu lien tue va giat manh, mdi l i n giat sffc gio CO the tang them 2-3 d p va lech hudng them. Neu ta dang d tren hudng di chuyen eua bao thi su thay doi hudng gio khong ro r i n g , nhUng gia trj do khi I p bj g i l m lien tue. Khi thay hudng gio doi chieu g i n n h d ngdpc h I n so vPi hddng ban d i u thi do la dau hieu tam bao da di qua. Tren d i t lien quan sat t h i y gid manh dan len, mda r i t Idn, sau bdng nhien ngdt mua, lang gio roi tiep den giai doan gio giat manh nhung co chieu ngUpe lai, mUa nhd trut - Do la
dau hieu tam b i o di qua. Chinh giai doan gio giat t r d lai sau do eo sffc t i n pha ghe g o m . Khi chdng bao p h i i quan tam den hien tupng nay de co bien phap neo e h I n g d bon phia cho chle c h i n .
6 tren bien, vl dong nddc vung t i m b i o x o l y manh, sdng dde va hon don nen tau thuyen roi vao khu vUe nay se het sffc nguy hiem. Viee thoat khoi tam bao chi la sff may m i n hiem eo.
Ket luan
- Bao cuoi mua thudng lui dan ve phia Nam nUdc ta, mac du it xuat hien nhung r i t nguy hiem vi sff chu quan va thieu hieu biet cua ngddi dan.
- d tren bien, khi khong the ve d i t lien thi hddng Oong Nam la hddng chay an toan eua tau thuyen khi hoat dpng d phia ben trai dUdng di cua bao.
-Tren tau d n l i p dat du trang thiet bi thong tin lien lac, thiet bj an loan, dU trff nhien lieu, thdc pham dff phong trudc khi ra khoi trong miia bao.
- Neu bj roi vao ban vong nguy hiem cua bao thi Quy t i c 3 phai la phddng an can thue hien de thoat.
- Nude bien dang eao, lu quel la hau qua tat yeu eua bao, n h i n d i n vung ven bien, vung nui d o c e a n d u p c s d t i n kipthdid^
Tai lieu tham khao:
[1]. Maritime meteorology - C.E.N Frankcom, London, 1985
[2]. Weather on Ocean - World data center for marine geology
[3.] Marine surface weather observations - National Weather Service
[4]. Bao va each chdng b i o cho tau thuyen - VO PHI HOANG,
1974
NXB KHKT
H. 4 Ducrng dl ciia cdc can bao cuoi mua a VN vd hu&ng chay trdnh bao an todn cua tdu thuyen
Tapchi HdnghdiVietNam • 5/2011 4 3
