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201820W (BEBINCA 貝碧嘉) - Profile 檔案

(First draft issued on September 9, 2018; final version issued on October 10, 2018)
(初稿於 2018 年 9 月 9 日發出,最後版本於 2018 年 10 月 10 日上載)

Brief profile of BEBINCA | 貝碧嘉小檔案:

JTWC number 聯合颱風警報中心 (JTWC) 號碼 20W
International number 國際編號 1816
Period of existence 生存時期 (JTWC) 2018/08/12 20 HKT - 2018/08/17 08 HKT
Lifetime 壽命 (JTWC) 4.50 days 日
Maximum 1-minute wind (JTWC) JTWC 一分鐘平均最高中心風速 55 knots 節 (Severe Tropical Storm 強烈熱帶風暴)
Minimum pressure (JTWC) JTWC 最低氣壓 982 hPa 百帕
Highest TC signal by HKO
香港天文台發出最高熱帶氣旋警告信號
3 (Strong Wind Signal 強風信號)
Closest point of approach by HKO
香港天文台所示之最接近距離
SSW 150 km (real-time warning 實時報告 / TC report 熱帶氣旋報告)
Time of closest approach by HKO
香港天文台所示之最接近時間
2018/08/14 11-14 HKT (real-time warning 實時報告) / 14 HKT (TC report 熱帶氣旋報告)
Lowest pressure recorded at HKO
香港天文台錄得的最低氣壓
994.7 hPa 百帕 (2018/08/12 17:34 HKT)

TC signals in Hong Kong 香港曾經生效的熱帶氣旋警告:

Signal
信號
Date and time
日期和時間
Distance from HK
與香港的距離
Predicted movement
預測移動趨勢
Max. 10-min winds
中心最高十分鐘平均風速
2018/08/09 (THU) 17:15 HKT SSW 540 km NNW at 12 km/h 45 km/h (25 knots, TD)
2018/08/14 (TUE) 05:20 HKT SSW 190 km Slow → N Slowly 85 km/h (45 knots, TS)
2018/08/15 (WED) 02:20 HKT SW 190 km NW/WNW at 8 km/h 85 km/h (45 knots, TS)
2018/08/15 (WED) 05:20 HKT SW 220 km W at 8 km/h 85 km/h (45 knots, TS)

Percentile Ranks 百分等級:

Percentile rank among storms with #3 Signal (at compilation of this review)*:
發出三號信號之風暴中的百分等級 (編寫此回顧之時)*:

*This measures the relative wind strength in Hong Kong caused by this storm compared with others that share the same signal. 指標顯示此風暴相對於其他發出同樣信號的風暴為香港帶來之風力強度

For more information, please refer to Wind Speed Data for TCs that Have Affected Hong Kong. 更多資訊載於 影響香港氣旋之風速數據

  Overall:
總計:
13
  Weak
Component Ranks 分部等級
  Reference stations:
參考站:
11
  Weak
  Victoria Harbour:
維多利亞港:
25
  Moderately weak
中等偏弱
  Urban:
市區:
9
  Weak
  Offshore & high ground
離岸和高地:
9
  Weak

Cyclones that attained similar rating (with signal #3): EWINIAR (2018), MAWAR (2017), DIANMU (2016), NALGAE (2011), NANGKA (2009), DAN (1999), PENNY (1998)
相近級別之熱帶氣旋 (三號信號):艾雲尼 (2018), 瑪娃 (2017), 電母 (2016), 尼格 (2011), 浪卡 (2009), 丹尼 (1999), 彭妮 (1998)

IR imagery animation 紅外線雲圖動畫:

TC track from HKWW 本站的熱帶氣旋路徑圖:

TC Track

TC tracks from HKO 天文台的熱帶氣旋路徑圖:

TC Track

TC Track

Past HKWW Bulletins 本站發佈

Please click here for bulletins on this tropical cyclone. 請按這裡

Storm Development Overview 風暴發展概覽

Unless otherwise stated, all times below are in Hong Kong Standard Time (UTC+8)
除非特別註明,下文時間均為香港標準時間 (協調世界時加 8 小時)

BEBINCA developed within the South China Sea as a broad area of low pressure on August 8. The Joint Typhoon Warning Centre (JTWC) issued a tropical cyclone formation alert on the system (96W) that night. 96W was initially expected to move north gradually towards western Guangdong due to a weak steering ridge that persisted in the eastern part of the South China Sea. However, numerical models were also suggesting the possibility of a brief eastward motion as the equatorial ridge was expected to strengthen.

The National Meteorological Center (NMC) of China upgraded 96W into a tropical depression at 8 am on August 9, with an initial forecast of persistent movement towards the north-northwest. The HK Observatory (HKO) also upgraded the system that afternoon. 96W moved north to north-northwest without much development over the next two days, making landfall near Yangjiang, Guangdong at around 11 am on August 11. Instead of moving inland, 96W moved southwest back into the South China Sea later that night, and turned east in response to a strengthening equatorial ridge.

During 96W's eastward motion, the storm gradually picked up strength with convections tightening mostly in its western semicircle. The JTWC upgraded it into tropical depression 20W during the night of August 12, predicting the storm to move east in the next day before looping back to the west. This was in line with model predictions with various models differing on the extent of the eastward track, due in part to the equatorial ridge and in part to the nearby tropical storm YAGI that was approaching Zhejiang at that time.

The Japan Meteorological Agency upgraded 20W into a tropical storm in the morning of August 13 and named it BEBINCA. BEBINCA's core developed gradually during the day and continued to move east. It decelerated again in the morning of August 14, moved north just west of 114°E and turned back to the west that afternoon. BEBINCA's convections then expanded in size, prompting both the NMC and HKO to upgrade it into a severe tropical storm.

BEBINCA maintained a generally westward motion on August 15 and made landfall at Leizhou Peninsula that night. It briefly weakened into a tropical storm before benefiting from the high ocean heat content in the Gulf of Tonkin on August 16. As BEBINCA moved west-southwest, it crossed the middle of the Gulf and strengthened again into a severe tropical storm. The storm accelerated and made a final landfall in northern Vietnam in the small hours of August 17. It continued to move west inland and weakened gradually into an area of low pressure that night.

貝碧嘉的雛型是 8 月 8 日於南海發展的一個廣闊低壓區。聯合颱風警報中心當晚對其 (96W) 發出熱帶氣旋形成警報。受南海東部的一道微弱高壓脊影響,初時預料 96W 將逐漸北移至廣東西部。可是,數值模式當時預測赤道高壓脊或將增強,96W 或短暫出現偏東路徑。

中國中央氣象台於 9 日上午 8 時將 96W 升格為熱帶低氣壓,並預料風暴持續向西北偏北移動。香港天文台亦於當天下午作出升格。96W 於其後兩天向北至西北偏北移動,但風暴無甚發展,於 11 日上午 11 時左右登陸廣東陽江一帶。登陸後,96W 並未進一步深入內陸,而是於當晚向西南移動並再度進入南海,其後因赤道高壓脊增強而轉東移。

96W 東移時對流 (尤其是西半圓) 逐漸收緊,風暴有所增強,聯合颱風警報中心於 12 日晚將其升格為熱帶低氣壓 20W,並預計風暴會於翌日東移,繼而轉回偏西移動。這預測與數值模式預報結果相似;各模式主要對風暴東移的幅度出現分歧,而東移的原因有二:一是受南方赤道高壓脊的影響,二是因為當時熱帶風暴摩羯正靠近浙江,兩系統間出現相互影響所致。

日本氣象廳於 13 日早上將 20W 升格為熱帶風暴,並命名為貝碧嘉。貝碧嘉的中心當天逐漸發展,風暴繼續東移。它於 14 日早上再度減速,於東經 114 度以西地方北移,繼而於下午轉向偏西。西轉後貝碧嘉的對流有所擴大,中國中央氣象台及香港天文台均將其升格為強烈熱帶風暴。

貝碧嘉於 15 日大致西移,當晚登陸雷州半島。它短暫減弱為熱帶風暴,但由於北部灣海洋熱含量高,它於 16 日橫過北部灣中部時再度增強為強烈熱帶風暴。貝碧嘉向西南偏西加速,於 17 日凌晨登陸越南北部,隨後繼續西移並於當晚減弱為低壓區。

Weather in Hong Kong During Approach 風暴影響時香港天氣狀況

Link to relevant HKO weather report bulletins: 9/810/811/812/813/814/815/8
香港天文台相關天氣報告連結9/810/811/812/813/814/815/8

The HKO issued the #1 Standby Signal at 5:15 pm on August 9, the time of its upgrade of 96W into a tropical depression. During the next few days, 96W maintained a considerable distance from Hong Kong. Nevertheless, Hong Kong was affected by BEBINCA's outer rainbands and most of the territory received more than 40 mm of rainfall on each of August 10, 11 and 12. The Amber Rainstorm Warning was issued three days in a row. BEBINCA gradually lost the characteristics of a monsoon depression during its eastward motion; its convections shrank in size and winds became more concentrated near its centre. The HKO mentioned several times between August 11 and August 13 that the #3 Signal may be considered, but the signal change was delayed because of the weak observed winds in Hong Kong.

The #3 Strong Wind Signal was eventually issued at 5:20 am on August 14, when BEBINCA started to turn north and was around 190 km south of Hong Kong. The signal replacement took place 108 hours and 5 minutes after the issuance of the #1 Signal, making it the second longest on record (after Typhoon DINAH in 1977). Winds turned east and strengthened somewhat during the morning, but they were way below strong force at many places (even weaker than several days ago, when the #1 Signal was in force) although BEBINCA was less than 200 km from the territory. Cheung Chau was the only reference station (out of 8) that registered strong force winds during the period when the #3 Signal was in force; all other stations that recorded strong winds, e.g., Tap Mun, Tate's Cairn and Waglan Island, were either at offshore areas or on high ground.

The HKO initially mentioned that BEBINCA would approach the vicinity of the Pearl River Estuary in its tropical cyclone report. This however did not materialize as the storm turned west after a period of stagnation in the morning of August 14. At around 150 km south-southwest of Hong Kong, BEBINCA was the closest to the territory in the early afternoon. Locally, there were a few squally showers in the afternoon of August 14, and winds moderated in the small hours of August 15. The Observatory replaced the #3 Signal by the #1 Standby Signal at 2:20 am when BEBINCA was 190 km southwest of the territory. This signal was cancelled just three hours later.

The weather in Hong Kong remained unstable during the next few days as convective activities associated with a trough persisted in southern China. It is interesting to note that the #8 Gale or Storm Signal was issued in Macau for 5 hours during BEBINCA's approach. However, BEBINCA's small wind radii meant that winds were much weaker than expected there as well.

香港天文台於 8 月 9 日下午 5 時 15 分作出升格時發出一號戒備信號。96W 於隨後數天與香港保持一段距離,但受其外圍雨帶影響,本港多處於 10、11 及 12 日每天雨量均超過 40 毫米,且每天均需發出黃色暴雨警告信號。貝碧嘉東移時逐漸失去季風低壓的特性,其對流及風場有所收縮。天文台於 11 至 13 日間多次表示會考慮改發三號信號,但由於本港風勢並未增強,改發時機亦多次延遲。

天文台最終於 14 日上午 5 時 20 分改發三號強風信號,當時貝碧嘉正北轉,處於香港以南約 190 公里。改發前一號信號共生效 108 小時又 5 分鐘,此為該信號生效時間第二長 (僅次 1977 年的颱風戴娜)。當天早上風向轉為偏東,風勢稍為增強;然而,雖然貝碧嘉距港不足 200 公里,但多處風力仍遠不及強風水平,比數天前一號信號生效時還低。三號信號生效期間,8 個參考測風站中只有長洲風力達強風程度,而其餘錄得強風的地點 (如塔門、大老山及橫瀾島) 均為離岸或高地地區。

天文台最初於其熱帶氣旋警報表示貝碧嘉會靠近珠江口一帶,但貝碧嘉於 14 日早上稍為停留一會後便轉西移,此預測並未實現。貝碧嘉於下午初段最接近香港,於本港西南偏南約 150 公里處掠過。下午本港有幾陣狂風驟雨,而 15 日凌晨風勢緩和。天文台於上午 2 時 20 分改發一號戒備信號,當時貝碧嘉位於香港西南約 190 公里,而此信號亦於三小時後取消。

受低壓槽相關的對流活動影響,其後數天香港天氣仍然不穩定。值得留意的是澳門曾於貝碧嘉靠近時懸掛八號風球達五小時,但由於貝碧嘉風場較為細小,當地風勢同樣比預期弱。

Image Gallery 圖片庫

Figure 1 - Steering flow map on August 12. Tropical Storm YAGI was approaching Zhejiang at that time.
圖 1 - 8 月 12 日之駛流場圖,當時熱帶風暴摩羯正靠近浙江

Figure 2 - Forecast track from the HKO on August 12
圖 2 - 8 月 12 日天文台之預測路徑

Figure 3 - Forecast tracks from various official agencies on August 14
圖 3 - 8 月 14 日各官方氣象台之預測路徑

Figure 4 - Satellite image of BEBINCA on August 14 (left) and a wind field analysis that morning (right)
圖 4 - 8 月 14 日貝碧嘉的衛星圖像 (左) 及當天早上的風場掃描 (右)

Figure 5 - Estimated wind field of BEBINCA at 2 pm August 14
圖 5 - 8 月 14 日下午 2 時貝碧嘉之估算風場圖

Figure 6 - Radar images at 3-hour intervals from 3 am to 6 pm August 14
圖 6 - 8 月 14 日上午 3 時至下午 6 時每三小時之雷達圖

Figure 7 - Wind speed time series at Chek Lap Kok, Cheung Chau, Tai Mei Tuk and Waglan Island (top to bottom) on August 14
圖 7 - 赤鱲角、長洲、大美督及橫瀾島 (上至下) 於 8 月 14 日之風速時間序列圖

Figure 8 - Satellite image showing BEBINCA crossing the Gulf of Tonkin
圖 8 - 貝碧嘉橫過北部灣時之衛星雲圖

Winds Recorded at Reference Stations 參考站所錄得的風速

Station
風速站
Max. 10-min avg. wind speed
最高十分鐘平均風速
Beaufort classification
蒲福氏風級分類
Chek Lap Kok 赤鱲角 35 km/h Fresh 清勁
Cheung Chau 長洲 61 km/h STRONG 強風
Kai Tak 啟德 29 km/h Moderate 和緩
Lau Fau Shan 流浮山 32 km/h Fresh 清勁
Sai Kung 西貢 36 km/h Fresh 清勁
Sha Tin 沙田 17 km/h Moderate 和緩
Ta Kwu Ling 打鼓嶺 19 km/h Moderate 和緩
Tsing Yi (SHL) 青衣蜆殼油庫 27 km/h Moderate 和緩

Number of stations recording at least STRONG force (force 6 - 7) winds: 1
Number of stations recording at least GALE force (force 8 - 9) winds: 0
Number of stations recording at least STORM force (force 10 - 11) winds: 0
Number of stations recording HURRICANE force (force 12) winds: 0

錄得 強風 (6 - 7 級) 或更高風速的站數: 1
錄得 烈風 (8 - 9 級) 或更高風速的站數: 0
錄得 暴風 (10 - 11 級) 或更高風速的站數: 0
錄得 颶風 (12 級) 風速的站數: 0

Charts and Figures 各項數據

Table 1: Track data from HKWW:
表一 : 香港天氣觀測站之路徑資料

YYMMDDZZ Lat Long Wind
18080906 177N1121E 025
18080912 181N1119E 025
18080918 184N1116E 030
18081000 191N1115E 030
18081006 200N1115E 030
18081012 203N1118E 030
18081018 208N1119E 030
18081100 213N1120E 030
18081106 219N1121E 030
18081112 215N1116E 030
18081118 213N1114E 030
18081200 210N1120E 030
18081206 211N1122E 035
18081212 206N1122E 035
18081218 206N1125E 040
18081300 206N1129E 040
18081306 206N1132E 040
18081312 206N1134E 045
18081318 206N1136E 045
18081400 208N1138E 045
18081406 210N1137E 045
18081412 210N1134E 045
18081418 211N1128E 050
18081500 207N1120E 055
18081506 210N1114E 055
18081512 208N1107E 050
18081518 207N1095E 045
18081600 203N1086E 050
18081606 200N1080E 055
18081612 198N1070E 055
18081618 197N1062E 055
18081700 195N1054E 045
18081706 194N1041E 035
18081712 194N1027E 025

Table 2: Maximum gust and hourly average wind speed recorded in Hong Kong from HKO:
表二 : 香港天文台公佈的各站最高每小時平均風力和陣風數據 (英文)

Station Maximum Gust Maximum Hourly Mean Wind
Direction Speed
(km/h)
Date/Month Time Direction Speed
(km/h)
Date/Month Time
Bluff Head (Stanley) SSE 52 10/8 03:05 ESE 31 9/8 18:00
Central Pier E 52 9/8 18:03 ESE 31 9/8 18:00
Cheung Chau SE 75 10/8 03:18 ESE 43 9/8 18:00
Cheung Chau Beach E 59 9/8 17:25 E 45 10/8 00:00
Green Island ENE 63 9/8 17:24 ENE 43 9/8 22:00
ENE 63 9/8 17:30
Hong Kong International Airport ESE 62 12/8 05:14 E 36 9/8 19:00
Kai Tak E 52 9/8 20:04 ESE 25 9/8 18:00
King's Park E 45 10/8 03:31 E 20 9/8 19:00
Lau Fau Shan E 51 9/8 17:37 ENE 27 9/8 22:00
North Point E 49 9/8 22:12 E 30 9/8 23:00
Peng Chau SSE 56 10/8 03:30 E 34 9/8 18:00
Ping Chau S 25 10/8 04:26 ESE 6 14/8 11:00
Sai Kung ENE 47 9/8 22:02 SSE 31 10/8 05:00
Sha Chau SSE 47 11/8 05:14 ESE 34 9/8 19:00
Sha Lo Wan SE 65 10/8 16:38 E 23 9/8 22:00
Sha Tin E 34 9/8 22:18 ESE 14 9/8 19:00
SSE 34 11/8 04:37
Star Ferry (Kowloon) E 51 9/8 17:20 E 30 9/8 18:00
Ta Kwu Ling E 41 9/8 19:37 E 16 9/8 20:00
Tai Mei Tuk SE 56 12/8 06:53 E 38 9/8 18:00
Tai Mo Shan ESE 79 10/8 23:36 ESE 59 11/8 00:00
Tai Po Kau SE 54 9/8 17:56 ESE 30 9/8 18:00
Tap Mun ESE 58 10/8 02:06 E 41 9/8 20:00
Tate's Cairn ESE 63 12/8 05:11 E 47 9/8 18:00
Tseung Kwan O ESE 40 9/8 18:15 ENE 13 13/8 12:00
ENE 13 13/8 13:00
ENE 13 13/8 14:00
Tsing Yi Shell Oil Depot SE 43 10/8 03:46 ESE 20 11/8 07:00
Tuen Mun Government Offices E 41 9/8 18:32 E 16 9/8 19:00
Waglan Island ENE 59 14/8 08:06 E 45 9/8 22:00
Wetland Park SSE 31 11/8 06:39 ESE 16 9/8 18:00
Wong Chuk Hang E 52 10/8 03:16 ENE 14 9/8 18:00
NE 14 9/8 22:00

Table 3: Rainfall (in millimetres) contributed by BEBINCA from HKO (figures in brackets are based on incomplete hourly data):
表三 : 香港天文台公佈的各站雨量資料 (英文) (方括號內之數據由不完整之每小時資料擷取)

Station 9 Aug 10 Aug 11 Aug 12 Aug 13 Aug 14 Aug 15 Aug Total rainfall (mm)
Hong Kong Observatory (HKO) Trace 47.9 51.9 18.9 0.1 32.9 2.2 153.9
Hong Kong International Airport (HKA) Trace 45.0 53.1 44.7 Trace 15.3 1.9 160.0
Cheung Chau (CCH) 0.0 51.0 [38.5] 41.5 11.0 14.5 2.0 [158.5]
H23 Aberdeen 0.0 47.5 51.5 43.0 5.0 20.5 3.5 171.0
N05 Fanling 0.5 36.5 77.5 69.5 0.0 28.0 9.0 221.0
N13 High Island 0.0 36.0 27.5 62.0 0.5 58.5 6.5 191.0
K04 Jordan Valley 0.5 55.0 57.0 29.5 2.0 26.5 4.0 174.5
N06 Kwai Chung 0.0 43.5 154.5 36.0 0.5 39.5 1.0 275.0
H12 Mid Levels 0.0 45.5 66.5 36.5 8.0 37.0 5.0 198.5
N09 Sha Tin 0.0 40.5 76.0 91.5 0.0 57.0 10.0 275.0
H19 Shau Kei Wan 0.0 55.0 26.0 21.5 15.0 30.5 0.0 148.0
K06 So Uk Estate 0.0 43.5 [125.0] 25.0 2.0 20.5 0.5 [216.5]
R31 Tai Mei Tuk 1.5 35.5 57.0 [77.0] [0.0] 18.0 17.0 [206.0]
R21 Tap Shek Kok 0.0 35.0 34.0 49.0 [0.0] 34.5 1.5 [154.0]
TMR Tuen Mun Reservoir 0.0 51.1 41.3 30.7 0.0 32.3 6.3 161.7

Last Accessed 最近訪問日期: Mon Dec 17 2018 20:44:20 HKT
Last Modified 最近修訂日期: Wed Oct 10 2018

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