Viing cira song Hdng thupc dong bdng Bdc Bp nen eac yeu td Ichf tuong mang dac didm chung eiia viing ddng bdng Bdc bp. ngoai ra vl la viing ven bidn ndn nd Cling cd nhung net dac thii do anh hudng ciia bidn
Che dp mUa.
Miia mua thudng bdt ddu vao thang V va kd't thiic vao thang X, song cung co nam bdt dau sdm han hoac kd't thuc mudn hem tir 15 den 30 ngay. Miia mua chiem
mua nam [5,11 ]. Miia ft mua keo dai tir thang XI den thang IV nam sau. tong iugng mua ca miia chi dat 10- 15 % lugng mua nam, thang mua ft nhat la thang XII.
Lugng mua trdn khu vuc ha luu song Hdng ed bie'n dpng khong Idn. iugng mua nam tai Ha Npi la 1690 mm, tai Van Ly 1600 mm.
Cudng dp mua d khu vuc nghidn ciiu ndi chung khong idn. it nai cd lugng mua ngay Idn nhat vugt qua 500 mm, chi cd nhimg dgt mua bao thi tdng lugng mua CO thd tdi 500- 800mm.
Che dp gid mua vd bdo.
Gid miia ddng bac thdi tir thang XI dd'n thang IV nam sau, co hudng thinh hanh la dong bac. bac va dong. Tinh trung binh mdi thang miia dong eo tir 3- 4 dot"
gid"Tanh tran vd vdi'tdc dp 3- 4 m/s (P = 70- 90 %). 8 m/s (P = 20- 30 ^'o va tham
chi cd khi tdc dp gid len tdi 10- 15 m/s. Gid miia dong bdc hoat dpng manh nhat vao
thang XII va thang 1 (P = 70- 80 %).
Gid miia tay nam tir thang V dd'n thang X. eo hudng thinh hanh la nam. dong nam va ddng. Tdc do gio trung binh la 4- 5 m/s. gid manh cd thd dat tdi 20- 25 m/s dac bidt la trong ap thap nhidt ddi va bao. Gid miia tay nam hoat dong manh nhat vao thang VI. thang VII va thang VIII.
Bao la nhidu dpng thdi tiet gay ra gid manh. mua Idn va keo dai d ddng bang Bdc Bp, gay ra sdng idn va muc nude bidn dang cao d viing ven bien. Bao thudng dd bo vao viing ven bidn Bdc bd tir thang VI (sdm la vao thang V) tdi thang X. hoat dpng manh nhat trong cac thang VII, VIII. Hang nam ddng bdng Bdc Bp phai humg chiu 3- 5 con bao dd bp vao.
Cac con bao vao ddng bdng Bdc Bp thudng cd cudng dp tir cap 9 dd'n cap 12, tham ehi tren cap 12 nhu cac can bao: Kate (1955), Rose (1968), Agnes (1984), Wayne (1986)...
Bao thudng gay ra ngap iing trong d6ng bdng, iam sat id bd va pha vo de viing ven bit^n. Nhung khoang mudi nam trd lai day, sd can bao va nhat ia bao Idn tren cap 9 dd bp vao viing ddng bdng Bac Bp ft hon trudc nhidu.
Hinh 2.1 Mang ludi sdng ddng bdng Bdc Bd