dupe each nude each nude

Thanh nien Trung tam KTTV Qudc Gia trong cdng tdc phdng chdng vd giam nhe thien tai

TINH TOAN PHAN TICH Ll/A CHON CHI TIEU KHA NANG

X U A T H I E N D O N G T l T SO L I E U P H A N H O I V O T U Y E N R A D A V A SO L I E U M A T D A T

CN. Hoang Minh Toan

D a i K h i tuong Cao Khong

So lieu radar rdt quan trong trong canh bdo thai tiet nguy hiem,

cd the canh bdo duoc ddng td ldc trudc 2-3 gia. Nhung de phdt huy hieu qua hon nua vd thiet thuc hon ddi cdc canh bdo thdi tiet nguy hiem, cdn cd cdc nghien cuu chi tieu canh bdo dua tren nguyen tdc bd sd lieu radar quan trac ddng bd vdi sd lieu mat ddt tit ndm 1999 den 2005, tir do cd cdc chi tieu canh bdo cho dia phuong. Ndi dung bdo cao nay tap trung nghien cuu chi tieu du bdo nhdn biet xudt hien ddng cho radar tai khu vuc Trung Trung Bd.

1. Md dau

Dong la mot hien tuong thoi tiet nguy hiem, thudng kem theo gio manh, mua rao, sam set du doi, tham chi ca mua da, v o i rdng. Nguyen nhan chinh tao ra ddng la ddi luu manh trong k h i quyen. Dam may ddi hru mudn cd tinh ddng manh thi phai phat trien den dd cao nao nd de cd qua trinh hoa bang cac hat nude trong may hay ndi each khac phai cd dieu kien de lam xuat hien cac hat may d cac trang thai pha khac nhau: dang nude ldng va dang bang. Tuy nhien neu cd hai dang hat nhung sd luong hat it, kich thudc hat nhd thi kha nang va cham de cd sir nhiem dien va phan chia dien tich dat t d i muc dd phdng dien ddng trong may Van khdng xay ra dupe. V i vay mudn cd hien tuong nhiem dien va phan chia dien tich trai dau de gay nen ddng kich thudc hat may phai du l d n va mat dd hat cung phai ldn hay ndi each khac dd phan hdi vd tuyen ( P H V T ) phai du ldn.

N h u vay ca dd cao dinh P H V T va gia t r i P H V T cung cd vai trd quan trong trong phat hien qua trinh tao nen hoat tinh ddng trong may, dd la co sd co ban sd dung t i m k i l m cac chi tieu. 0" vao giai doan dau cua ddng manh cd the thay nhung dau hieu phan hdi v d tuyen d cac muc cao hon so v d i trong ddng khdng manh. Dieu do do ddng thang manh dem cac hat mua len tren cao. Nhieu nghien cdu da cho thay rang n h i l u cua ddng thang trong ddng phat trien t u 7 - 9km. Thuc te neu dd cao cua phan h i i v d tuyen may len t d i 50dBZ tai 9km d dd cao khoang t h i ddng cd t h i coi la phat t r i l n trung binh hay la manh. Neu cd mua da d mat dat thi ddi k h i hat mua da cd dudng kinh 5 cm cd the thay dupe trong khu vuc cd phan hdi vd tuyen

Hpi thao khoa hgc Thanh nien tan thir II 76

Thanh nien Trung tam KTTV Qudc Gia irons cdng tdc phdng chdng va giam nhe thieh tai

Theo each tien hanh phan tich anh nhu tren, de dang xac dinh duac t i m bao j t i n s i 37 GHz la 15.2°N - 116.5°E va d t i n s i 85 GHz la 15.2°N - 116.4°E.

Bang 2. Ket qua xac dinh v i t r i t i m bao Xangsane tai tai OOz ngay 29/09/2006 T i m bao xac dinh

bang anh song ngan t i n s6 37 GHz

T i m bao xac dinh bang anh song ngan

t i n so 85 G H z \ r

T i m bao tong hop t u h a i anh

T i m bao duoc phat b d i trung

t i m N h i t 1 5 . 2 ° N - 1 1 6 . 5⁰E 1 5 . 2 ° N - 1 1 6 . 4 ° E . 1 5 . 2 ° N - 1 1 6 . 5 ° E . ^ " N - m ^ E .

5. K e t luan va kien nghi

Su dung anh song ngan trong nghiep v u xac dinh t i m bao r i t co y nghia, dac biet trong cac dieu kien t i m bao b i may C i che phu, t i m bao nam trong vung may doi luru phat trien manh hoac trong dieu kien ban dem k h i khong co anh t h i p h i .

Anh song ngan khi co bao dugc cung c i p thong qua trang Web cua Hai quan M y co the dugc truy cap 15 phut mot lan trong dieu kien cho phep. D i y se la mot dieu kien het sdc thuan Igi doi v d i nghiep v u p h i n tich va du bao bao.

C i n su dung ket hop anh song ngan v d i cac san pham quan trac khac nhu anh thi pho, anh hong ngoai va Quyckscat, ... va xem xet them cac dac diem c i u true cua can bao. T u do co phuang phap tong hop cac k i t qua trudc k h i dua ra k i t luan

r t

cuoi cung.

A n h song ngan dai t i n so 85GHz con co the cung c i p cac udc lugng v l mua trong bao. D o do, loai anh nay r i t huu ich cho cong tac canh bao va dir bao mua do bao tai Trung t i m D u bao K h i tugng Thuy van Trung uong. V i vay, c i n t i l n hanh nhieu nghien curu han nua de viec ap dung anh song ngan dat dugc hieu qua va gop

* p h i n n i n g cao c h i t lugng dur bao.

Tai lieu tham khao

1. Microwave, analysis - Joe Courtney - Bureau Of Meteorology, Australia

2. Microwave Remote Sensing: Overview - Meteorology Education and Training website 3. Microwave Remote Sensing: Clouds, Precipitation and water vapor - Meteorology Education and Training website

4. Polar satellite products for the operational forecaster: Microwave products and applications - Meteorology Education and Training website

5. Polar satellite products for the operational forecaster: Microwave analysis of Tropical Cyclones - Meteorology Education and Training website

6. Trang web: http://www.nrlmrv.naw.mil/tc pages/tc home.html

75

Thanh nien Trung tam KTTV Qudc Gia trong cdng tdc phdng chdng vd giam nhe thien tai

may d 50dBZ. Qua s i lieu quan trac bang ra da nguoi ta t h i y rang, mot thap may Cb don le co duong kinh tir 7-10km. Trong do kich thuoc ciia vung co chuyen dong thang va giang Ion nhat cung chi khoang 2km. Neu cac chuyen dong thang va giang co dang chuyln dong hoan luru khep k i n thi vung c h u y l n dong nay xet mot each trung binh chi chiem khoang mot nua thiet dien ngang cua thap may dong.

2. Phan loai dang phan hoi vo tuyen may dong tren anh ra da va xac dinh gia P H V T dong v o i t r a m quan trac mat dat

2.1. Dang PHVT may ddi luu

Tren anh ra da P H V T may doi l u u co gradient ngang tuong d i i Ion, gradient thang dung tuong doi nho. M a y doi l u u manh thuong co t i c do chuyln dong thang dung manh. Tren hinh 1 vung P H V T may doi l u u la nhung vung duoc phan dinh bang mau vang dam.

Hinh 1. Anh phan hoi vo tuyen may d i i luu va may ting

Nhin chung PHVT may doi luu chuyen dong voi toe do trung binh ciia gio moi

truong xung quanh chiing. Toe do di chuyen ciia 6 may doi luu lien quan chat che v o i toe do dong dan tren mat 700hPa. V i the nguoi ta thuong su dung anh P H V T 6 do cao 3km de xac dinh toe do va huong di chuyen ciia vung P H V T dang theo doi.

D i i v o i may^: doi luu phat trien manh co do cao cao tren 15km thuong phai canh bao toe do va huong di chuyen theo gia t r i trung binh ve hudng va toe do gio d 850hPa, 700hPa va 500hPa.

2.2. Dang PHVT may tang

Ngupc lai v d i tinh chat cua may doi luu, P H V T co gradient ngang tuong d i i nho, gradient thang dung tuong d i i ldn. Viing may tang thudng c h i l m mpt dien tich kha rpng va co toe dp chuyen dpng thang dung nho, phan bo deu. M a y t i n g cho mua cudng dp ldn thudng phat trien t d i dp cao tren 5km, co vung dinh P H V T kha d i n g deu va thudng quan trac dupe vung dai sang d muc nhiet dp 0^{o C} ( d vung nhiet

Hdi thao khoa hoc Thanh nien ldn thir II 11

Thanh nien Trung tam KTTV Quoc Gia trong cdng tdc phong chdng vd giam nhe thien tai

ddi noi chung va d nude ta noi rieng do cao trung binh cua tang 0^{o C} la 5km). Tren hinh 1 vung may t i n g phan ldn dupe phan dinh b i n g dai mau xanh v d i gia t r i cudng do nho.

2.3. Phdn dinh khach quan vung mdy ddi luu khd ndng gdy ddng vd mdy tdng bang phdn hdi vd tuyen radar

Viec phan dinh may doi luu v d i may tang dupe tien hanh doi v d i trudng P H V T tren mat cat ngang d mdc dp cao 3km each mat dat (san pham CAPPI) trong l u d i 6 vuong la 2 k m x 2km. r>mung gia t r i P H V T l d n hon hoac bang ngudng chi tieu cho trudc se dupe nhan biet la tdm mdy doi luu. X u n g quanh tam may doi luu co vung bdn kinh may ddi luu phu thupc vao gia t r i P H V T trung binh nen. Sau k h i phan dinh, vung may t i n g dupe kiem tra lai qua chi tieu dai sang (Churchill va Houze (1984), Steiner va Houze (1993)). Phuong phap dupe mo ta chi tiet d phan tiep theo.

Tdm may ddi luu: Bat ky diem l u d i nao co dp phan hoi vo tuyen ldn hon hoac bang 35 dBZ deu dupe t u dpng gan trd thanh tam may doi lvru, v i dp phan hoi nay thuc te khong bao gio la phan hoi vo tuyen cua may tang d vung nhiet ddi (hinh 2).

ySBBm

* * * * * *

* a * * * * »

r^'JWWiJTf¹¹* , , , » » fc'ahxuogqiualltam dbi Uru 11 km , , * , 10 im * * * * • * • » • * • • • < * *

Hinh 2. Ludi phan tich vung may ddi luu cd kha nang gay ddng (khoang each giua hai nut la 2km)

Viing ldn can: (Gia tri phan hdi cao nhit trong mdt khu vyc) bit ky didm ludi

nao cd dp phan hdi vd tuyen khdng dupe xac dinh la tam ddi luu d budc d i u tidn nhung cd gia t r i ldn hon gia tri trung binh ndn cung dupe coi la tam may ddi luu, tinh theo cdng thuc thuc nghidm [Steiner (1995)]. D d la nhung diem l u d i cd dp phan hdi vd tuyen nhd hon 35dBZ, k h i so sanh v d i P H V T trung binh ndn (Ztb) trong vung ban kinh 11km each tam may ddi lvru. Gia tri A Z dupe bidu didn qua he thdc:

Thanh nien Trung tam KTTV Quoc Gia trong cong tdc phong chdng va giam nhe thien tai

AZ = 10

Z² 10----*

180 0

Z .t< 0

0 < Zt b < 3 5 d B Z Zt b > 3 5 d B Z

( D

Xac dinh ban kinh ciia may doi luu la ham ciia do phan hoi trung binh quanh tam may doi l u u . U n g v d i do thi (hinh 3) doi v d i tam may doi l u u co do phan hoi cang manh t h i ban kinh cang ldn va giam dan ban kinh theo muc giam dan gia tri do phan hoi. Tren do co ba muc lira chon moi quan he giua do phan hoi v d i ban kinh cua may doi luu: muc nho, muc vua va muc rong.

CP C «">

-«D *—'

>

<o © Xi c

i

6° 20 35 60 (dBZ)

Trung binh phan hoi vo tuyen cua vung (dBZ)

Hinh 3. M6i quan he giua chenh lech phan hoi vo tuyen vdi trung binh phan hdi vd tuyen duoc su dung de xac dinh tam may ddi luu.

Phan dinh may ddi luu va may tang dupe thuc hien trong ludi toa dd Be-cac.

V d i du lieu phan hdi vd tuyen d do cao 3 k m de tranh anh hudng cua "dai sang" d m u c 0 ° C .

33 i

PQ 10 20 3D 40 50 (dBZ)

Hinh 4. Mdi dudng xac dinh vdi mdt ban kinh ddi luu tuong ung vdi mdt khoang each km nhat dinh.

0 vung nhiet ddi thudng cd dd cao muc 0^{o C} xap x i bang 5 k m . Trong khoang dd cao 3 k m t d mat dat tuy hat mua cd bay hoi nhung chung khdng anh hudng ddn

Hdi thao khoa hoc Thanh nien ldn thir II 79

Thanh nien Trung tam KTTV Quoc Gia trong cdng tdc phdng chdng vd giam nhe thien tai

do phan hoi vo tuyen boi bay hai chi xay ra manh ddi vdi cac hat nho, con cudng do

mua va P H V T mua dugc xac dinh chu ydu b d i cac hat ldn. Trong phuang phap tach may d6i luu va may t i n g can thuc hien hieu chinh lien tuc cac chi tieu cho phu hgp.

Cac tram quan t r i e k h i tugng bd mat dugc lira chon trong pham v i ban k i n h quet cua ra da. Do ra da co luc hoat dong khong dn dinh, nhieu tin hidu ndn phai kidm tra rung anh, loai bo anh khong du tidu chuan hoac xac dinh thai didm cd so lidu quan trie dong d tram k h i tugng bd mat.

i; •" - Ve hinhehi'ti thj no duno

•1.3. •!- 10 -—•- — V .J: J _ o 1 1

o JO

"-rr

- \ JO JO > • 40 . JO AC

<«0 Hinh 5. Ket qua xac dinh tam ddi luu va lan can r r r

2.4. So lieu ddng tie tram quan trdc mat ddt.

Sd lieu dugc l i y t u kdt qua quan t r i e k h i tugng be mat v d i thai gian b i t d i u va kdt thuc hidn tuong, sd lan xuat hidn ddng trong ngay. {Xem phdn phu luc)

3. Xac dinh, t i n h toan va danh gia chi tieu nhan biet xuat hien ddng 3.1. Ly thuyet xdc dinh chi tieu nhan biet xudt hien ddng.

Hien nay trong phan tich du bao xuat hidn ddng bang sd lieu P H V T ra da dang sd dung cac chi tidu t d nude ngoai va mdt so nha khoa hoc cung xay dung cac chi tidu nhung v d i quy md nhd, sd lugng sd lieu dau vao thap. Ndn mdc do khang dinh dng dung vao nude ta la chua cao. Do do, can cd lugng sd lieu dau vao du ldn dd danh gia va xay dung eac chi tidu sau cho phu hgp hon.

C h i tieu doc lap: D d cao dinh may ddi luu >16km hoac lgZ3>~3.0 ( l g Z3 la P H V T d dd cao H = H 0°C+2km)

C h i tieu tdng hop Y : Y = H x Z3 v d i H la dd cao dinh P H V T may va Z3 la P H V T d dd cao 7 km.

3.2. Tinh todn vd phdn tich cdc chi tieu

Co so du lidu d i u vao: bao gdm t u nam 1999 den hdt nam 2004, trong dd radar gom 1210 ban ghi sd lieu, ddng tram mat d i t gom 720 ngay cua 6 tram

Thanh nien Trung tam KTTV Qudc Gia trong cong tdc phong chong va giam nhe thien tai

Tinh toan: phan liy gia tri PHVT trung voi cac toa do tram quan trac hien

tuong dong mat d i t tao ra mot bo sd lieu dong ra da. L i y sd lieu quan trac dong tai cac tram quan t r i e k h i tuong duoc bo sd lieu thu hai goi la sd lieu dong mat dat.

Danh sach tram mat dat duoc dua ra trong hinh 6.

Viec chuan hoa co sd d u lieu: Hieu chinh ve thoi gian tram ra da cd nhung thdi ky su dung theo G M T . So do khoi chuong trinh dupe trinh bay trong hinh 7.

1 1 f -^rr

A 8 C D E. f G : . H c

3

±

5 Nam Iking Xua't Idea

±

5 Nam Iking

Iinl Iin2 Iifl3 Iin4 iki 6 2004 4 1 1520-1620

7 8 2310-2340 8 12 1810-1840

DNang/fDong/Hue-/Tr*!y/B3To/(?ig3/ >\z BTHW.t: Table

MA TEN ' KINHDO VIDO 001 Song Hdi 106.6' 17.4S33333333 002 • Bong Ha 107.083: 16.85 003 I Hue" 107.583; 16.433 004 A Luai 107.166! 16.217 005 jNam Oang 107.717! 16.167 006 Da Ning 108.2 16.033 007 " ;Tam Ky 108.467: 15.567 008 Tra My ^! 108.2331 15.35 0O9 Quang Ngai 108.8: 15.117 010 •Ba To 108.733: 14.767 011 ; Hoai Nhdn 109.0333333331 14.5166666667 012 ;TuyHoa 109.283333333^: 13.0833333333 013 Konlum 108; 14.35 014 Pleiku 108.016666667 13.9666666667 015 :Su6nM§Thu6l 106.051 12J567 016 03 Ul 108.45; "11.95 Hinh 6. Danh sach cac tram l i y sd lieu ddng mat dat va dinh dang file sd lieu

X-Axfe

Kelqiro

Hinh 7. So dd khdi chuong trinh chuan hda co sd du lieu

3.3. Ket qua

Cac ket qua danh gia cho chi tieu ddc lap cho thay rang v d i do cao dinh may 16km thi trd thanh chi tieu ddc lap (> 16 k m t h i kha nang xuat hien ddng se la

>88.26 % ) . Gia t r i P H V T t h i p n h i t cho ddng la 31.29 dBZ (xem Wnh 8). Cac kdt qua danh gia oho chi tidu tdng hop dupe trinh bay trong hinh 9.

Hdi thao khoa hgc Thanh nien tan thu II 81

Thanh nien Trung tam KTTV Qudc Gia trong cone tdc Phone chdng vd siam nhe thien wi

100 80 sz 60

•<±>- JE 40 X 20 0

Chi tieu Dong

** •

i H i f l l 500 600 700 800

Y

900 1000 100 _ 80

= 60 5 40

* 20 0

Chi tieu Dong

- i

500 600 700 800 900 1000 Y

Hinh 8. Ket qua danh gia cho chi tieu doc Hinh 9. Ket qua danh gia cho chi tieu tong

lap hop

4. K e t luan

Chi tieu xuat hien dong la may phat trien Ion hon 16 k m va phan h6i cao nhat tai tam hoac loi may Ion hoti 31.29 dBZ. C h i tieu t i n g hop gia t r i P H V T tai 7km nhan Hmax >780 la kha nang xuat hien dong rat cao. B e nghi cho trien khai ung dung thuc te va danh gia ket qua va tinh toan tiep v o i c h u l i thoi gian day va dai hon.

T a i lieu t h a m khao

1. Tuyen tap khoa hoc Dai Khi Tuong Cao Khong. 2001.

2. Tai lieu tap huan Rada Dai Khi Tuong Cao Khong. 2002

3. Tran Tan Tien - Nguyen Dang Qui, X u l i s6 lieu K h i tuong va D u bao thoi t i l t bang phuang phap Thing ke Vat ly, Nha xuat ban Dai hoc Qulc Gia Ha Noi, 2002.

4. Trail Cong Minh, K h i tuong va Khi hau dai cuong, Nha xuit ban Dai hoc Qulc Gia Ha Noi, 2006

5. Churchill, D. D., and R. A. Houze, Jr., 1984: J. Atmos, Sci., 41, 1717-1725.

6. Schmid, W., L . L i , H.-H. Schiesser, and R. A . Houze, Jr., 1993: Rotation in Swiss hailstorms: Doppler-radar structure and the environmental wind field. Preprints, 17th Conference on Severe Local Storms, St. Louis, American Meteorological Society, 196-200.

Hdi thao khoa hoc Thanh nien ldn thuII 82

Thanh men Trung tam KTTV Qudc Gia trong cons tdc ph Phu luc

Bo s6 lieu dong ra da co gia tri vi tri tuong duong tram quan trie mat dit.

199907161600 003 Hue SSW 265.33 7.62 34.82

199907161600 005 Nam Dong E 297.09 8.28 35.88 199907161600 005 Nam Dong SEE 333.8 8.47 39.41 199907161600 005 Nam Dong SE 340.91 7.81 43.65 199907161600 005 Nam Dong SSE 343.87 8.28 41.53 199907161600 005 Nam Dong S 357.58 9.41 38.00 199907161600 005 Nam Dong SSW 464 11.67 39.76 199907161600 005 Nam Dong N W W 265.33 7.62 34.82 199907161600 005 Nam Dong N W 265.33 7.62 34.82

199907161600 006 Da Nang w 336.98 7.72 43.65

199907161600 006 Da Nang N W 197.44 6.31 31.29

Bo so lieu dong cua tram quan trac mat dat 006 2004 9 8 1800-1900 006 2004 9 9 1900-1940

006 2004 9 17 2030-2135 2230-2310 0130-0150 006 2004 9 19 1650-1740

006 2004 10 2 2100-2130 0200-0510 850-1120 006 2004 10 27 0840-0900

005 2004 3 23 1615-1700 005 2004 3 24 1350-1500 005 2004 3 25 1540-1610 005 2004 3 30 1550-1900

005 2004 4 1 1900-1940 1610-1750 005 2004 4 2 1630-1820

Hpi thao khoa hoc Thanh nien thn thir II 83 3 3