Bookmark and Share

TC Watch / 熱帶氣旋 > Selected TC Review / 重要熱帶氣旋回顧 > 201710W (ROKE 洛克) [Refresh 更新]

201710W (ROKE 洛克) - Profile 檔案

(First draft issued on August 13, 2017; final version issued on September 3, 2017)
(初稿於 2017 年 8 月 13 日發出,最後版本於 2017 年 9 月 3 日上載)

Brief profile of ROKE | 洛克小檔案:

JTWC number 聯合颱風警報中心 (JTWC) 號碼 10W
International number 國際編號 1707
Period of existence 生存時期 (HKO 香港天文台)* 2017/07/22 14 HKT - 2017/07/23 20 HKT
Lifetime 壽命 (HKO) 1.25 days 日
Maximum 10-minute wind (HKO) 估計 10 分鐘平均最高中心風速 35 knots 節 (Tropical Storm 熱帶風暴)
Highest TC signal by HKO
香港天文台發出最高熱帶氣旋警告信號
8 (NW) (Gale or Storm Signal 烈風或暴風信號)
Closest point of approach by HKO
香港天文台所示之最接近距離
N 20 km (real-time warning 實時報告) / NE 25 km (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
2017/07/23 11 HKT (real-time warning 實時報告) / 10 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
1004.0 hPa 百帕 (2017/07/23 09:47 HKT)

*The information about this storm from JTWC is incomplete and is thus replaced by that from the HKO.
*由於聯合颱風警報中心的資料不完整,我們改為使用香港天文台的風暴資料。

TC signals for Hong Kong & Track 香港曾經生效的熱帶氣旋警告和路徑圖:

Table 表:

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
2017/07/22 (SAT) 15:40 HKT ESE 460 km WNW at 25 km/h 45 km/h (25 knots, TD)
2017/07/23 (SUN) 03:40 HKT ESE 170 km WNW at 20 km/h 65 km/h (35 knots, TS)
2017/07/23 (SUN) 09:20 HKT E 60 km W/WNW at 20 km/h 65 km/h (35 knots, TS)
2017/07/23 (SUN) 13:20 HKT NW 60 km W/WNW at 20 km/h 65 km/h (35 knots, TS)
2017/07/23 (SUN) 15:10 HKT WNW 100 km W/WNW at 20 km/h 45 km/h (25 knots, TD)
2017/07/23 (SUN) 19:40 HKT WNW 190 km W/WNW at 18 km/h 40 km/h (20 knots, LPA)

Figure 圖:

(Track figure courtesy of Lorenzo. Data from HKO. 鳴謝 Lorenzo 提供路徑圖,資料取自天文台)

TC Track

Percentile Ranks 百分等級:

Percentile rank among storms with #8 Signal (at compilation of this review)*:
發出八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:
1
  Weak
Component Ranks 分部等級
  Reference stations:
參考站:
0
  Weakest
最弱
  Victoria Harbour:
維多利亞港:
3
  Weak
  Urban:
市區:
0
  Weakest
最弱
  Offshore & high ground
離岸和高地:
0
  Weakest
最弱

Cyclones that attained similar rating (with signal #8): LINFA (2015)
相近級別之熱帶氣旋 (八號信號):蓮花 (2015)

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

*Green dots represent reports of gales near Roke's path. 綠點顯示在洛克路徑附近的烈風報告。

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)

A patch of convections developed near the Luzon Strait early on July 21. The JTWC issued a tropical cyclone formation alert to this system at 8 am that day, and upgraded the system into tropical depression 10W at 2 am the next day. 10W was moving west-northwest along the southern periphery of a subtropical ridge anchored near Shanghai, and was expected to make a close approach to Hong Kong during the weekend.

The convections associated with 10W expanded during the day of July 22 and its spiraling characteristics improved. Without first issuing a gale warning, the JMA upgraded 10W directly into a tropical storm at 2 pm and named it ROKE. This also prompted the HKO to upgrade the system into a tropical depression shortly after.

ROKE moved west-northwest steadily during the night of July 22 and morning of July 23. The HKO upgraded ROKE into a tropical storm at 2 am July 23. ROKE made landfall near Sai Kung East Country Park at around 10 am, becoming the first tropical cyclone to make landfall at Hong Kong since Typhoon NURI in 2008. After landfall, ROKE deflected north towards the Hong Kong-Shenzhen border. The storm crossed the Pearl River Estuary near noon and continued its way across southern Guangdong.

As a small and weak system, ROKE disintegrated quickly after landfall. The HKO downgraded ROKE into a tropical depression at 2 pm and further into an area of low pressure near 8 pm the same day.

一團對流雲帶於 7 月 21 日早上在呂宋海峽附近發展。聯合颱風警報中心於當天上午 8 時為其發出熱帶氣旋形成警告,繼而於翌日上午 2 時將其升格為熱帶低氣壓 10W。當時副熱帶高壓脊中心於上海一帶,10W 沿該脊南部向西北偏西移動,並預料會於周末非常接近香港。

與 10W 相關的對流於 22 日擴展,其螺旋形態有所改善。下午 2 時,日本氣象廳於沒有發出烈風警告的情況下直接將 10W 升格為熱帶風暴,並將其命名為洛克。香港天文台隨即升格該系統為熱帶低氣壓。

洛克於 22 日晚及 23 日早上穩定向西北偏西移動;天文台於 23 日 上午 2 時將洛克升格為熱帶風暴。洛克於上午 10 時左右登陸香港西貢東郊野公園,成為自 2008 年颱風鸚鵡以來首個登陸香港的熱帶氣旋。登陸後洛克的路徑北偏,靠近香港深圳邊界一帶。風暴於中午左右通過珠江口,並繼續橫過廣東南部。

由於洛克較為細小,強度亦不高,它登陸後快速解體。天文台於下午 2 時將洛克降格為熱帶低氣壓,最後於同日下午 8 時左右將其降格為低壓區。

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

Link to relevant HKO weather report bulletins: 22/7 23/7
香港天文台相關天氣報告連結22/7 23/7

The HKO issued the #1 Standby Signal at 3:40 pm July 22, or shortly after upgrading ROKE into a tropical depression. The initial forecast track had ROKE making landfall close to, but still east of Hong Kong. The HKO indicated that higher signals were not likely that night. Locally, the weather was generally fine on July 22.

Later that night, as ROKE was steadily approaching the territory, the HKO mentioned that the #3 Signal would be considered before 6 am July 23. From information gathered from buoys and ships in the South China Sea, the HKO determined that ROKE had reached tropical storm strength and made the upgrade at 2 pm. The handling of empty cargoes was also suspended at about the same time. Because ROKE was expected to be very close to Hong Kong in the morning, the HKO issued the #3 Strong Wind Signal at 3:40, when ROKE was around 170 km east-southeast of the territory. Winds were mostly blowing in from the north, but the wind speeds were not much different from a normal day.

ROKE moved west briefly during the night and the HKO's forecast track in the small hours had ROKE passing south of or through Hong Kong. At 7 am, the HKO indicated that due to ROKE's anticipated close approach, the wind direction would change from the north to south quickly; members of the public were reminded to stay alert. The Pre-No. 8 Special Announcement was issued at 7:20 am, warning that the #8 Signal would be issued within the next 2 hours.

The #8 Northwest Gale or Storm Signal was eventually issued at 9:20 am, when ROKE was located around 60 km east of the Observatory. ROKE's rainbands started to affect Hong Kong near 9 am; however, as most of the storm's convections were concentrated in its eastern side, the rainfall intensity was rather weak. Winds at many places also picked up, but they were still generally below strong force level except at several offshore or elevated areas such as Waglan Island, Green Island, Tap Mun and Tate's Cairn. Due to the #8 signal, public transport services were gradually suspended. The Hong Kong Book Fair and various sports activities scheduled for that afternoon were also affected.

According to the HKO, ROKE made landfall at the Sai Kung East Country Park near 10 am. The storm moved northwest briefly afterwards, entering Shenzhen an hour later and passed 20-30 km to the north of the Observatory. From the publicly available data, the best piece of evidence of ROKE's landfall at Hong Kong is perhaps the change in wind direction at Tap Mun --- it is the only station where winds veered from the northwest to southeast near 10 am; all other stations experienced a backing in the wind direction. However, most of Hong Kong avoided ROKE's windiest part and, as a result, none of the anemometers within the territory registered gale force winds during its approach. Even strong winds were not observed generally and none of the eight reference station reached the strong wind threshold.

Following its approach, ROKE crossed the Pearl River Estuary and moved towards Zhongshan and adjacent areas. Winds in Hong Kong backed to the south or southeast near noon, and started to subside in the late afternoon. The #3 Strong Wind Signal was issued to replace the #8 Signal at 1:20 pm, and was replaced by the #1 Standby Signal at 3:10 pm. Various services, exhibitions and events were resumed in the afternoon.

ROKE weakened into an area of low pressure around 200 km from Hong Kong soon after sunset; the #1 Signal was therefore lifted at 7:40 pm. The weather remained unstable that night as a rainband swept across the territory. The Amber Rainstorm Warning was issued at 10:30 pm that night and remained in force for more than 2 hours.

天文台於 7 月 22 日下午 3 時 40 分,即升格洛克為熱帶低氣壓後不久發出一號戒備信號。初時的預報圖顯示洛克將會較為接近香港,但仍於本港以東登陸。天文台表示當晚改發更高信號機會不大。本地方面,22 日天氣大致天晴。

隨著洛克穩定朝香港方向前進,天文台於當晚稍後時間表示將於 23 日上午 6 時前考慮改發三號信號。23 日上午 2 時,天文台從南海浮標及船舶觀測數據推斷洛克已達熱帶風暴強度,因此作出升格。本港貨櫃碼頭亦於此時暫停吉櫃交收服務。由於預計洛克將於早上非常接近本港,天文台於上午 3 時 40 分改發三號強風信號,當時洛克於香港東南偏東約 170 公里。本港風向主要為偏北,但風勢並不比平常猛烈。

凌晨時洛克曾短暫西移,天文台曾將預測路徑改為洛克於香港以南掠過或直趨香港。上午 7 時,天文台表示,由於預料洛克將於香港近處掠過,風向將由偏北迅速轉為偏南,市民應提高警覺。預警八號熱帶氣旋警告信號之特別報告於上午 7 時 20 分發出,即預計將於兩小時內改發八號信號。

天文台最終於上午 9 時 20 分發出八號西北烈風或暴風信號,當時洛克於天文台以東約 60 公里。洛克的雨帶於上午 9 時左右開始影響本港;但由於風暴大多數對流活動集中在其東面,因此本港雨勢較弱。本港多區風力開始上升,但大多未達強風程度,只有部分離岸及高地站點如橫瀾島、青洲、塔門及大老山等錄得強風。由於八號信號發出,交通工具服務暫停,而當時正舉行的香港書展及即將於當天下午舉行的體育活動亦受影響。

按照天文台的發佈,洛克於上午 10 時左右在西貢東郊野公園登陸。風暴隨後短暫向西北移,一小時後進入深圳境內,並於天文台以北約 20 至 30 公里掠過。眾多公開數據當中,風暴曾登陸香港的最佳證據為塔門的風向於 10 時左右由西北順轉為東南,而香港其他地區風向均逆轉。可是,由於香港大多數地區並未受洛克風勢最強的部份影響,因此洛克掠過時並未有風速站錄得烈風,廣泛地區 (包括八個參考測風站) 就連強風亦沒有。

洛克靠近香港後橫過珠江口,繼而趨向中山及鄰近地區。香港風向於中午已逆轉為南至東南風,並於下午較後時間減弱。天文台於下午 1 時 20 分改發三號強風信號,並於下午 3 時 10 分改發一號戒備信號。各類服務、展覽及比賽項目均於下午恢復。

洛克於日落後不久於距離香港約 200 公里的地方減弱為低壓區,天文台遂於下午 7 時 40 分取消一號信號。香港當晚天氣仍然不穩定,一道雨帶於晚間掃過本港,黃色暴雨警告於下午 10 時 30 分發出,並維持超過 2 小時。

Image Gallery 圖片庫

Figure 1 - Satellite image of ROKE at formation, together with a wind field analysis which depicted the presence of strong force winds.
圖 1 - 洛克形成時之衛星雲圖,隨附的風場掃描顯示風暴附近吹強風

Figure 2 - Steering flow chart at 8 am July 22
圖 2 - 7 月 22 日上午 8 時之駛流場圖

Figure 3 - Radar image from the CWB at 11 am July 22
圖 3 - 7 月 22 日上午 11 時台灣中央氣象局的雷達圖

Figure 4 - HKO's forecast tracks at 2 pm July 22 (left) and 2 am July 23 (right); a passage south of Hong Kong was predicted in the latter plot.
圖 4 - 7 月 22 日下午 2 時 (左) 及 23 日上午 2 時 (右) 天文台的預測路徑圖,其中後者顯示預計洛克會於香港以南掠過

Figure 5 - Forecast tracks from official agencies at 8 pm July 22 (left) and 8 am July 23 (right)
圖 5 - 7 月 22 日下午 8 時 (左) 及 23 日上午 8 時 (右) 各官方氣象台之預測路徑圖

Figure 6 - Weather observations from ships and various weather stations around the South China Sea early on July 23. Note in particular the ship near 22.4°N, 116.0°E (indicated by the red arrow) which reported gale force easterly winds (42 knots, 78 km/h) at 2 am that day.
圖 6 - 7 月 23 日早段南海附近的船舶及氣象站的天氣觀測數據,留意於北緯 22.4 度、東經 116.0 度附近 (紅箭頭示) 有船隻於當天上午 2 時錄得達烈風程度 (42 節,每小時 78 公里) 的東風

Figure 7 - Weather conditions in the South China Sea as ROKE closed in on Hong Kong. The tropical depression near Hainan Island would later develop into tropical storm SONCA.
圖 7 - 洛克逼近香港時南海天氣狀況圖,靠近海南島的熱帶低氣壓之後發展為熱帶風暴桑卡

Figure 8 - Satellite image of ROKE near its closest point of approach to Hong Kong
圖 8 - 洛克
於最接近香港時的衛星雲圖

Figure 9 - Animation of the evolution in wind speeds/directions at various places in Hong Kong between 7 am and 1 pm July 23. Note in particular the veering wind at Tap Mun, from northwest to southeast.
圖 9 - 7 月 23 日上午 7 時至下午 1 時間香港各區風速風向變化動畫,留意塔門風向由西北順轉至東南

Figure 10 - ROKE's track near Hong Kong as reported in HKO's hourly tropical cyclone bulletins
圖 10 - 洛克於香港附近時之路徑,資料來自天文台的每小時熱帶氣旋警報


Figure 11 - Radar images at 3-hour intervals from 2 am to 5 pm July 23
圖 11 - 7 月 23 日上午 2 時至下午 5 時每三小時之雷達圖

Figure 12 - Radar image showing ROKE about to make landfall at eastern Hong Kong
圖 12 - 雷達圖顯示洛克即將登陸香港東部


Figure 13 - Local wind disitribution maps at 3-hour intervals from 2 am to 5 pm July 23
圖 13 - 7 月 23 日上午 2 時至下午 5 時每三小時之本港風勢分布圖

Figure 14 - Wind speed time series at Cheung Chau, Tai Mei Tuk, Tap Mun and Waglan Island (top to bottom) on July 23
圖 14 - 長洲、大美督、塔門及橫瀾島 (上至下) 於 7 月 23 日的風速時間序列圖

Figure 15 - Sea level pressure time series at the Hong Kong Observatory and Ta Kwu Ling (top to bottom) on July 23
圖 15 - 香港天文台及打鼓嶺 (上至下) 於 7 月 23 日的海平面氣壓時間序列圖

Figure 16 - Ms. Lee Shuk-ming, Senior Scientific Officer at the HKO, explained the necessity of issuing the #8 Signal as gales were recorded at various places near ROKE's path. Click here for the video of the press briefing.
圖 16 - 香港天文台高級科學主任李淑明女士解釋由於洛克沿途附近曾錄得烈風,因此有需要發出八號信號。按此觀看此新聞發佈會。

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 30 km/h Moderate 和緩
Cheung Chau 長洲 37 km/h Fresh 清勁
Kai Tak 啟德 28 km/h Moderate 和緩
Lau Fau Shan 流浮山 36 km/h Fresh 清勁
Sai Kung 西貢 31 km/h Fresh 清勁
Sha Tin 沙田 18 km/h Moderate 和緩
Ta Kwu Ling 打鼓嶺 17 km/h Moderate 和緩
Tsing Yi (SHL) 青衣蜆殼油庫 24 km/h Moderate 和緩

Number of stations recording at least STRONG force (force 6 - 7) winds: 0
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: 0
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
17072200 209N1206E 025
17072206 212N1190E 030
17072212 216N1179E 035
17072218 217N1162E 040
17072221 220N1154E 040
17072300 223N1148E 040
17072303 225N1142E 035
17072306 227N1133E 035
17072312 229N1119E 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)
E
38
23/7
15:23
E
20
23/7
16:00
Central Pier
ESE
40
23/7
15:37
E
25
23/7
16:00
Cheung Chau
ESE
52
23/7
15:53
ESE
34
23/7
17:00
Cheung Chau Beach
E
49
23/7
15:55
E
36
23/7
17:00
Green Island
NNW
59
23/7
08:05
NNW
40
23/7
09:00
Hong Kong International Airport
ESE
41
23/7
16:44
ESE
27
23/7
17:00
Kai Tak
ENE
45
23/7
15:37
WNW
22
23/7
09:00
King's Park
N
41
23/7
07:13
ESE
13
23/7
15:00
SE
13
23/7
16:00
Lau Fau Shan
NNW
45
23/7
09:32
NNW
31
23/7
10:00
Ngong Ping
E
68
23/7
14:08
E
41
23/7
19:00
North Point
WSW
40
23/7
09:42
WSW
30
23/7
10:00
E
40
23/7
15:41
Peng Chau
E
45
23/7
15:53
E
25
23/7
17:00
Ping Chau
ENE
67
23/7
09:13
E
19
23/7
10:00
Sai Kung
N
54
23/7
07:50
N
23
23/7
08:00
N
23
23/7
09:00
Sha Chau
NNW
41
23/7
09:36
ESE
27
23/7
17:00
Sha Lo Wan
SE
38
23/7
14:29
SE
14
22/7
20:00
Sha Tin
N
34
23/7
08:08
SSW
14
23/7
11:00
Shek Kong
ENE
41
23/7
15:20
ENE
19
23/7
16:00
Star Ferry (Kowloon)
E
40
23/7
15:51
W
27
23/7
10:00
Ta Kwu Ling
NNW
34
23/7
09:05
NNW
14
23/7
10:00
Tai Mei Tuk
NNE
62
23/7
08:37
E
31
23/7
15:00
Tai Mo Shan
N
70
23/7
09:20
SE
49
23/7
14:00
SE
70
23/7
13:21
ESE
49
23/7
17:00
SE
70
23/7
13:26
Tai Po Kau
W
47
23/7
09:36
E
25
23/7
16:00
Tap Mun*
N
72
23/7
09:18
E
36
23/7
15:00
Tate's Cairn
N
68
23/7
07:55
N
45
23/7
08:00
Tseung Kwan O
NNW
40
23/7
08:30
NNW
14
23/7
08:00
NNW
14
23/7
09:00
Tsing Yi Shell Oil Depot
NW
38
23/7
06:58
SE
19
22/7
16:00
NW
38
23/7
07:00
SE
19
22/7
17:00
NW
38
23/7
07:10
NW
19
23/7
08:00
Tuen Mun Government Offices
SE
31
23/7
13:37
SSE
16
22/7
16:00
Waglan Island
NNW
59
23/7
07:57
NNW
40
23/7
08:00
Wetland Park
N
30
23/7
08:54
NNW
12
23/7
10:00
N
30
23/7
08:58
N
30
23/7
09:02
Wong Chuk Hang
E
34
23/7
16:05
E
12
23/7
16:00

*The old wind station on the rooftop of Tap Mun Police Post is replaced by the new Tap Mun station on July 6, 2017.
*新塔門測風站在 2017 年 7 月 6 日取代在塔門警崗屋頂的舊測風站。

Table 3: Rainfall (in millimetres) contributed by ROKE 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 22 Jul 23 Jul 24 Jul
Total Rainfall (mm)
Hong Kong Observatory (HKO)
3.3
46.5
3.3
53.1
Hong Kong International Airport
(HKA)
0.4

9.1

1.6
11.1
Cheung Chau (CCH)
1.0
9.0
0.5
10.5
H23 Aberdeen
0.5
48.5
4.5
53.5
N05 Fanling
5.0
32.5
8.5
46.0
N13 High Island
14.5
36.0
21.5
72.0
K04 Jordan Valley
0.0
19.0
17.5
36.5
N06 Kwai Chung
0.0
14.5
8.0
22.5
H12 Mid Levels
4.5
70.5
11.0
86.0
N09 Sha Tin
5.5
31.0
9.0
45.5
H19 Shau Kei Wan
2.0
29.5
7.5
39.0
SEK Shek Kong
[0.5]
[17.5]
[5.0]
[23.0]
K06 So Uk Estate
1.0
17.5
6.5
25.0
R31 Tai Mei Tuk
[0.5]
[27.5]
[35.5]
[63.5]
R21 Tap Shek Kok
[0.0]
[30.0]
[4.5]
[34.5]
TMR Tuen Mun Reservoir
[0.1]
46.0
16.4
[62.5]
N17 Tung Chung
0.0
17.0
2.5
19.5

Last Accessed 最近訪問日期: Sun Apr 22 2018 08:31:35 HKT
Last Modified 最近修訂日期: Wed Oct 25 2017

觀看訪客統計報表 Web Traffic Statistics

Statistics