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 201331W (HAIYAN 海燕) - Profile 檔案 |
(Issued on December 8, 2013)
(於 2013 年 12 月 8 日發出)
Brief profile of HAIYAN 海燕小檔案:
| JTWC number 聯合颱風警報中心 (JTWC) 號碼 | 31W |
| International number 國際編號 | 1330 |
| Period of existence 生存時期 (JTWC) | 2013/11/03 14 HKT - 2013/11/11 20 HKT |
| Lifetime 壽命 (JTWC) | 8.25 days 日 |
| Maximum 1-minute wind (JTWC) JTWC 一分鐘平均最高中心風速 | 170 knots 節 (Category 5 Super Typhoon 五級超級颱風) |
| Minimum pressure (JTWC) JTWC 最低氣壓 | 895 hPa 百帕 |
| Highest TC signal by HKO (if applicable) 香港天文台發出最高熱帶氣旋警告信號 |
N/A 不適用 |
| Closest point of approach by HKO (if applicable) 香港天文台所示之最接近距離 (如適用) |
N/A 不適用 |
| Time of closest approach by HKO (if applicable) 香港天文台所示之最接近時間 (如適用) |
N/A 不適用 |
| Lowest pressure recorded at HKO (if applicable) 香港天文台錄得的最低氣壓 (如適用) |
N/A 不適用 |
TC track from HKWW 本站的熱帶氣旋路徑圖:
| Past HKWW Bulletins on HAIYAN 本站有關海燕的發佈 |
Please click here for bulletins on HAIYAN. 請按這裡。
| Storm Summary 氣旋摘要 |
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)
HAIYAN is undoubtedly the strongest tropical cyclone this year on the planet, and is the strongest landfalling typhoon since records began.
Being one of the last storms to form in a spate of tropical cyclone events since September, HAIYAN developed as a disturbance near Chuuk in early November at latitudes as south as 6°N. The disturbance intensified into tropical depression 31W in the afternoon of November 3. As is usual in this season, the subtropical ridge was firmly anchored in the Pacific at that time. 31W was thus expected to track W/WNW and impact the Philippines.
The area was very favourable for storm development because of very low vertical wind shear and the warm sea surface temperatures. 31W became more organized on November 4, and was upgraded into a tropical storm by the JMA at 8 am. Tha named assigned to 31W was HAIYAN. It was contributed by China, meaning petrel. Due to the stability of the subtropical ridge, forecast tracks among different agencies were very consistent. The only difference was perhaps the track speed --- under strong steering force, HAIYAN was expected to accelerate to above 30 km/h.
HAIYAN's circulation expanded and became tighter on November 4. The JTWC upgraded HAIYAN into a typhoon in the morning of November 5. Moderate intensification took place during the day, and forecasts started to predict intensification to category 4 before HAIYAN's landfall at eastern Philippines. The JMA seemed to be rather late in upgrading HAIYAN into typhoon status. The upgrade was made at 2 am November 6; by that time HAIYAN's central dense overcast had already been established with a small eye embedded in it.
HAIYAN underwent rapid intensification during the night. Its intensity was estimated at 105 knots (194 km/h) by the JTWC at 2 am November 6. This was revised upwards to 130 knots (241 km/h) at 8 am as its eye cleared a bit. The storm's eyewall cloud top temperature dropped to below -80 degrees during the day, indicating very strong convective activity near the storm's centre. The intensity estimate increased to 135 knots (250 km/h) at 2 pm and further to 140 knots (259 km/h) at 8 pm, making HAIYAN the fourth category 5 super typhoon in this basin in 2013. The JMA also adjusted its intensity estimate quickly, from 80 knots (148 km/h) in the morning to 90 knots (167 km/h) in the afternoon and 110 knots (204 km/h) at night.
The storm's eye enlarged as it became category 5. Its convections were concentrated near the centre, and the cloud bands were relatively sparse in its periphery. The storm reacted to a slight intensification of the ridge to its east, and started to pick up some latitude. It has also accelerated to around 30 km/h. Over the night of November 6-7, HAIYAN maintained its extremely deep convections (i.e. the area within which cloud top temperatures reached -80 degrees, appearing as a yellow ring in NRL's colour-enhanced infrared imageries). This prompted the JTWC to upgrade HAIYAN further to a 150-knot system (278 km/h). The convective activity weakened slightly at daybreak, and together with diurnal variation the yellow ring became broken although still covering a substantial part of the central dense overcast. HAIYAN's eye, however, remained very clear throughout.
After some period of consolidation, HAIYAN's central dense overcast deepened near dusk on November 7. The yellow zone re-emerged and this time covered essentially the whole eyewall. The storm acquired some characteristics of an annular cyclone; its round eye was deeply embedded within a very thick eyewall, but spiraling bands could still be observed in its periphery. The coverage and persistence of this yellow area was extremely rare in recent history, and as a result the JTWC further upgraded HAIYAN's estimated intensity to 165 knots (306 km/h) at 8 pm. Such an intensity had never been seen in decades. It tied with super typhoon TIP's peak intensity, and is the highest since reliable records began. The JMA also reacted to HAIYAN's excellent structure by upgrading its intensity to 125 knots (232 km/h) --- the fourth cyclone to reach this strength since records began.
As a result of the lack of reconnaissance aircrafts, intensity estimates were almost entirely based on the Dvorak technique. The assessment at 8 pm was in the range of T7.5 to T8.0, this being the upper limit of the scale. The technique provided no guidance on the estimation of intensity of a cyclone that maintained a yellow disc (corresponding to CDG/Cold dark grey in the original colour scheme) because of its rarity, and this limitation was acknowledged in one of the cyclone fix bulletins (see Table 3). HAIYAN remained such an excellent structure overnight and the JTWC further upgraded it to a 170-knot system (315 km/h) at 2 am November 8, a few hours before its landfall. This is the intensity in the Dvorak coversion chart corresponding to a system graded T8.0. This assessment made HAIYAN the strongest tropical cyclone ever, in terms of 1-minute sustained wind speed, since reliable records began (there were a few cyclones that exceeded this intensity before 1970, but these are generally deemed overestimated). The intensity estimates given by different agencies are summarized in the following table:
| Agency | Strength at 8 pm, Nov 7 | Strength at 2 am, Nov 8 | Strength at 8 am, Nov 8 |
| JTWC / US (1-min) | 165 knots (306 km/h), 899 hPa | 170 knots (315 km/h), 895 hPa | 160 knots (296 km/h), 903 hPa |
| NMC / China (2-min) | 75 m/s (270 km/h), 890 hPa | 75 m/s (270 km/h), 890 hPa | 72 m/s (259 km/h), 892 hPa |
| JMA / Japan (10-min) | 125 knots (232 km/h), 895 hPa | 125 knots (232 km/h), 895 hPa | 125 knots (232 km/h), 895 hPa |
| HKO / Hong Kong (10-min)* | 250 km/h | 260 km/h | 250 km/h |
| CWB / Taiwan (10-min) | 63 m/s (227 km/h) | 63 m/s (227 km/h) | 63 m/s (227 km/h) |
| KMA / Korea (10-min) | 119 knots (220 km/h), 890 hPa | 119 knots (220 km/h), 890 hPa | 115 knots (213 km/h), 900 hPa |
* In HKO's annual TC report, HAIYAN's maximum intensity was adjusted upwards to 285 km/h.
Just a few hours after this upgrade, HAIYAN made landfall at Guiuan in Eastern Samar near 5 am. The landfall was brief and at around 7 am, it made its second landfall at the island of Leyte, passing just south of Tacloban. Leyte is a larger island and HAIYAN started to weaken more quickly. Its eye shrank in size and the yellow region diminished. At 35-38 km/h, HAIYAN maintained a very high speed while crossing the Philippines. It reached Panay near 11 am and spent the afternoon crossing western Philippines. Due to HAIYAN's extreme wind speed and destructive storm surge, regions near HAIYAN's initial landfalls suffered catastrophic damage, especially in the vicinity of Tacloban. Cities and villages were inundated and most weaker constructions were blown away. The death toll in the country exceeded 5,000; this makes HAIYAN one of the deadliest natural disasters (and the second deadliest tropical cyclone) in the Philippines.
Most meteorological equipment in the landfall area broke or was blown away during HAIYAN's impact; it is therefore almost impossible to ascertain HAIYAN's actual strength at its full fury. Storm chasers at Tacloban (iCyclone page) recorded 960.8 hPa and 960.3 hPa on their two devices at 7:12 and 7:20 am respectively --- that was when HAIYAN was passing to its south. According to Jeff Master's blog, a barometer at Tacloban airport (1 mile south of the hotel the storm chasers were residing) registered 955.6 hPa at 7:15 am before power was lost. This and the fact that the airport is around 17 miles from the storm centre gives a linearly extrapolated pressure of between 880 and 890 hPa at HAIYAN's centre. Since the pressure gradient is likely to be even steeper near its centre, HAIYAN could well have minimum pressure less than 880 hPa before it reached Leyte. However, unless further readings are available, it is impossible to tell whether HAIYAN is stronger than TIP which had a minimum pressure of 870 hPa (lowest pressure ever recorded). It is worth noting that an unofficial reading of 889 hPa was recorded at Guiuan at 5:01 am, but there is no subsequent verification of its validity.
Due to its high initial intensity, HAIYAN lost substantial strength while crossing the relatively flat terrain in the Philippines. JTWC's intensity estimate decreased from 170 knots (315 km/h) to 160 knots (296 km/h) just after HAIYAN's landfall, and further to 145 knots (269 km/h) at 2 pm. It weakened into category 4 before moving into the South China Sea in the night of November 8. Although HAIYAN's structure was still compact, land interaction resulted in a cloud-filled eye and slightly asymmetric appearance.
Regarding HAIYAN's track, numerical models and official agencies were predicting a gradual turn to the NW as the subtropical ridge was forecast to weaken. However it was uncertain whether the storm would make landfall in central Vietnam, causing further damage. HAIYAN turned west briefly, before resuming a WNW track on November 9. HAIYAN never recovered its round eye, and kept weakening while travelling in the South China Sea.
HAIYAN eventually avoided central Vietnam as it turned even more poleward in the night of November 9-10. The storm entered Hong Kong's 800 km area on November 10, and later skirted the southwestern coast of Hainan. Land interaction became apparent again and HAIYAN lost intensity at a quicker pace. It finally made landfall near the China-Vietnam border early on November 11 as a marginal typhoon, and soon recurved as it reached the subtropical ridge axis. However, without the supply of moisture HAIYAN weakened fairly rapidly inland; although it started to move east, there was no significant threat to Hong Kong. Due to the combined effect of HAIYAN and the subtropical ridge, winds in Hong Kong were rather strong on November 10/11 with occasional showers. A teenager was drowned as he was swept away by waves at Cheung Sha Beach in Lantau on November 10. HAIYAN's remnants brought heavier rain to the territory on November 12, and 33.4 mm of rainfall was recorded at the Observatory on that day.
海燕無疑是本年全球最強熱帶氣旋，且為有紀錄以來登陸時最強的颱風。
西北太平洋自九月開始不斷有熱帶氣旋形成，海燕是該連串風暴中較後的一個。海燕前身的熱帶擾動在 11 月初在楚克島一帶發展，位置低至北緯 6 度，該擾動於 3 日下午增強為熱帶低氣壓 31W。副熱帶高壓脊於當時盤據西北太平洋，因此預料 31W 會向西或西北偏西移動，趨向菲律賓。
由於垂直風切變十分低而且海水溫暖，該區非常適合熱帶氣旋發展。31W 於 4 日變得較有組織，於上午 8 時被日本氣象廳升格為熱帶風暴，被命名為海燕，而此名字由中國提供。由於副高型態穩定，各氣象台預測的路徑頗為一致，但由於流場強勁，海燕的移速預測達每小時 30 公里，各台於預測移動速度上有少許分歧。
海燕的環流於 4 日擴大且逐漸變得緊密。聯合颱風警報中心於 5 日早上將海燕升格為颱風。海燕於當天繼續增強，預測開始顯示它將以四級強度登陸菲律賓東部。另一方面，日本氣象廳升格的時間略嫌太遲，至 6 日上午 2 時才將海燕升格為颱風，當時海燕的中心密集雲區已發展，中心可見細小風眼。
海燕當晚快速增強，聯合颱風警報中心估算強度由 6 日上午 2 時的 105 節 (每小時 194 公里) 跳升至上午 8 時的 130 節 (每小時 241 公里)，而海燕的風眼漸轉清晰。風暴的眼牆雲頂溫度當天跌至 -80 度以下，代表中心附近的對流活動十分猛烈。海燕的估計風速於下午 2 時被調升至 135 節 (每小時 250 公里)，六小時後進一步增加至 140 節 (每小時 259 公里)，成為 2013 年西北太平洋第四個五級超級颱風。日本氣象廳亦將海燕的強度逐次調升，由早上的 80 節 (每小時 148 公里) 增至下午的 90 節 (每小時 167 公里) 及晚間的 110 節 (每小時 204 公里)。
隨著海燕達到五級強度，其風眼範圍擴展。它的對流集中在中心附近，周邊雲帶較少。副高於海燕東面南伸，海燕的緯度因此略有增加，並加速至每小時 30 公里左右。海燕於 6 日晚間維持其極深層對流 (即雲頂溫度達 -80 度的區域，於美國海軍研究實驗室提供的色調強化紅外線衛星雲圖上以黃色表示)，這令聯合颱風警報中心進一步提高海燕的強度至 150 節 (每小時 278 公里)。破曉後對流活動稍為減少，同時亦因溫度上升關係，黃色環狀區出現破損，但仍覆蓋中心密集雲區不少面積。海燕的風眼則一直保持清晰。
經過一輪整固後，海燕的中心密集雲區於 7 日黃昏再次發展，黃色區域重新出現，並幾乎覆蓋整個眼牆。這時海燕擁有一些環狀颱風的特徵，例如其眼牆十分厚實，而風眼則於其正中心處，但不同於環狀颱風的是它仍有不少外圍環流。黃色區域覆蓋範圍之廣及持續時間之長是近期極為罕見的，聯合颱風警報中心亦因此於晚上 8 時上調強度至 165 節 (每小時 306 公里)。此強度數十年未見，平了超級颱風泰培的巔峰強度，亦是自有可信紀錄以來最高的。日本氣象廳亦因為海燕結構極佳而將強度上調至 125 節 (每小時 232 公里)，是歷來第四個颱風達此強度。
由於沒有飛機偵察數據，海燕的強度幾乎完全由德沃夏克方法估算出來。下午 8 時的評估為 T7.5 至 T8.0，此為強度表的上限。由於十分罕見，德法並未對能維持渾圓黃區 (即原色階中的 CDG/Cold dark grey) 的熱帶氣旋提供強度估算對照，此限制於其中一個熱帶氣旋位置發佈中有所提及 (見表三)。海燕於晚間繼續維持此極佳結構，聯合颱風警報中心最終於海燕登陸前數小時，即 8 日凌晨 2 時將其風速上調至 170 節 (每小時 315 公里)，亦為德法風速換算表中 T8.0 所對應的強度。這使海燕成為自有可靠紀錄以來一分鐘平均風速標準下最強勁的熱帶氣旋 (1970 年以前曾有數個颱風達更高風速，但一般認為當時傾向高估它們的強度)。各氣象台估算強度如下表：
| 機構 | 11 月 7 日晚上 8 時強度 | 11 月 8 日凌晨 2 時強度 | 11 月 8 日早上 8 時強度 |
| JTWC / 美國 (一分鐘平均) | 165 節 (306 公里/時), 899 百帕 | 170 節 (315 公里/時), 895 百帕 | 160 節 (296 公里/時), 903 百帕 |
| NMC / 中國 (兩分鐘平均) | 75 米/秒 (270 公里/時), 890 百帕 | 75 米/秒 (270 公里/時), 890 百帕 | 72 米/秒 (259 公里/時), 892 百帕 |
| JMA / 日本 (十分鐘平均) | 125 節 (232 公里/時), 895 百帕 | 125 節 (232 公里/時), 895 百帕 | 125 節 (232 公里/時), 895 百帕 |
| HKO / 香港 (十分鐘平均)* | 250 公里/時 | 260 公里/時 | 250 公里/時 |
| CWB / 台灣 (十分鐘平均) | 63 米/秒 (227 公里/時) | 63 米/秒 (227 公里/時) | 63 米/秒 (227 公里/時) |
| KMA / 韓國 (十分鐘平均) | 119 節 (220 公里/時), 890 百帕 | 119 節 (220 公里/時), 890 百帕 | 115 節 (213 公里/時), 900 百帕 |
* 於香港天文台的熱帶氣旋年報，海燕的最高強度被上調至每小時 285 公里。
升格後不久，海燕於清晨 5 時在東薩馬省基萬一帶登陸。這次登陸非常短暫，風暴其後於上午 7 時登陸萊特島，於獨魯萬 (或稱塔克洛班) 市以南掠過。由於萊特島較大，海燕減弱速度加快，它的風眼縮小，黃區亦逐步縮窄。海燕以每小時 35 至 38 公里的高速橫過菲律賓，它於早上 11 時左右到達班乃島，並於下午橫過菲律賓西部。由於海燕風速極高加上風暴潮的侵襲，其首兩次登陸點一帶遭受災難性破壞，情況於獨魯萬附近尤為嚴重。不少城市和村莊被浸沒，較弱的建築物大多被吹走。海燕於菲國造成超過五千人死亡，令其成為該國最多人死亡的天災之一 (熱帶氣旋相關天災則為第二位)。
由於風暴吹襲時大多數於登陸點附近的氣象儀器都被破壞或吹走，所以未能準確測量到海燕最強時的強度。專程到獨魯萬市的追風人士分別於當天上午 7 時 12 及 20 分於其下榻酒店中的兩台儀器上分別錄得海平面氣壓 960.8 及 960.3 百帕。根據 Jeff Master 的文章，於該酒店以南約 1 英里的獨魯萬機場於 7 時 15 分錄得氣壓 955.6 百帕，隨後電源中斷。由於風暴中心當時相距機場約 17 英里，利用線性推算可估計海燕中心氣壓達 880 至 890 百帕。一般來說越接近颱風中心氣壓梯度越高，這顯示海燕中心氣壓於登陸萊特島前或低於 880 百帕。但是，除非有更多數據，否則無法確定海燕的氣壓曾否比泰培所保持的最低紀錄 870 百帕還要低。值得一提的是，有一段信息指基萬於早上 5 時 01 分曾錄得氣壓 889 百帕，但未能證實讀數的可信性。
由於海燕登陸時強度十分高，雖然它橫過菲律賓相對平坦的陸地，但減弱的幅度較大。聯合颱風警報中心的估算強度由 170 節 (每小時 315 公里) 下調至登陸後不久的 160 節 (每小時 296 公里)，再而於下午 2 時下降至 145 節 (每小時 269 公里)。它其後減弱為四級颱風，並於 8 日晚上進入南海。雖然海燕的結構仍然緊密，但陸地影響導致其風眼被填塞，外型亦有點不對稱。
路徑方面，數值預報及官方預測均表示副高減弱將令海燕逐漸轉向西北移動，但未能肯定風暴會否登陸越南中部，造成更多破壞。海燕短暫西移，但於 9 日回復西北偏西的路徑。海燕一直未能修復其渾圓的風眼，並於南海橫過時逐漸減弱。
海燕於 9 日晚向較北方向移動，避過登陸越南中部。它於 10 日進入香港 800 公里範圍，其後於海南島西南部對開掠過。受地形影響，海燕減弱速度再次加快。它最終於 11 日早段以颱風下限強度在中越邊界一帶登陸，橫過副高脊線後於內陸轉向。由於水氣供應被截斷，海燕於陸上快速減弱，雖然它開始東移但未對香港構成嚴重威脅。受海燕及副高共同影響，本港風勢於 10 至 11 日較為強勁，並伴隨驟雨。一青年於 10 日在大嶼山長沙泳灘嬉水時被浪捲走，隨後證實死亡。海燕的殘餘於 12 日為香港帶來大雨，天文台於當天錄得 33.4 毫米雨量。
| Figures 圖片 |
Figure 1 - Satellite image of HAIYAN at 10:30 am November 4
圖 1 - 11 月 4 日上午 10 時 30 分之衛星圖
Figure 2 - Steering flow chart at 8 am November 6
圖 2 - 11 月 6 日上午 8 時之駛流圖
Figure 3 - Forecast tracks from different agencies, November 5
圖 3 - 11 月 5 日各氣象台之預測路徑
Figure 4 - Satellite image at 10:30 November 7 showing HAIYAN's clear eye. It was at category 5 at that time.
圖 4 - 11 月 7 日上午 10 時 30 分之衛星圖，海燕的風眼清晰可見，當時海燕已增強為五級超級颱風
Figure 5 - CWB's colour-enhanced infrared satellite image showing HAIYAN's extremely intense convections (white ring)
圖 5 - 台灣中央氣象局的色調強化紅外線衛星雲圖顯示海燕的極深層對流 (白色環)
Figures 6a and 6b - HAIYAN at record-breaking peak intensity of 170 knots
圖 6a 及 6b - 海燕處於破紀錄的巔峰強度 170 節
Figure 7 - JTWC's forecast track showing current intensity at 170 knots
圖 7 - 聯合颱風警報中心的預測路徑圖顯示當時估算強度 170 節
Figure 8 - Forecast tracks from different agencies, November 7/8
圖 8 - 11 月 7/8 日各氣象台之預測路徑
Figure 9 - The advanced Dvorak technique for automatic assessment of the Dvorak T number showed a peak exceeding the cap of the scale
圖 9 - 用來評估德法 T 號碼的自動化系統曾出現超過容許範圍上限的奇景
Figure 10 - Calculated wind field at 2 am November 8. Note the perhaps impossible sea level pressure estimate.
圖 10 - 11 月 8 日上午 2 時之估算風場圖，留意近乎沒有可能達到的海平面氣壓估計
Figures 11a to 11c - HAIYAN making landfall at Leyte (IR, colour-enhanced IR and visible imageries in order)
圖 11a 至 11c - 海燕正登陸萊特島 (左起為紅外線、色調強化紅外線及可見光衛星雲圖)
Figure 12 - Radar image depicting HAIYAN's passage to the south of Tacloban
圖 12 - 雷達圖顯示海燕於獨魯萬市以南掠過
Figure 13 - A weakened HAIYAN in the South China Sea
圖 13 - 已減弱的海燕橫過南海
Figure 14 - Steering flow chart at 8 am November 10
圖 14 - 11 月 10 日上午 8 時之駛流圖
Figure 15 - HAIYAN made landfall and moved northwards into China
圖 15 - 海燕登陸並北移入中國內陸
| Other Data 其他數據 |
Table 1: Track data from HKWW:
表一 : 香港天氣觀測站之路徑資料
| YYMMDDZZ Lat Long Wind 13110306 062N1562E 025 13110312 062N1547E 030 13110318 062N1532E 030 13110400 061N1520E 035 13110406 062N1504E 040 13110412 064N1489E 045 13110418 065N1476E 055 13110500 065N1461E 060 13110506 065N1446E 065 13110512 069N1431E 075 13110518 071N1412E 090 13110600 073N1397E 115 13110606 076N1379E 130 13110612 080N1362E 140 13110618 082N1344E 150 13110700 087N1328E 150 13110706 093N1311E 150 13110712 101N1291E 165 13110718 106N1269E 170 13110800 110N1248E 160 13110806 114N1225E 145 13110812 118N1206E 135 13110818 124N1182E 125 13110900 125N1165E 115 13110906 135N1148E 105 13110912 145N1131E 100 13110918 154N1114E 100 13111000 165N1102E 095 13111006 179N1090E 090 13111012 193N1080E 085 13111018 205N1075E 075 13111100 216N1073E 065 13111106 226N1077E 055 |
Table 2: Track data from JTWC:
表二 : 聯合颱風警報中心之路徑資料
ID Name YYMMDD ZZZZ Lat Long Basin Wind Pres 31W HAIYAN 131111 1800 24.4N 110.2E WPAC 20 1007 |
Table 3: Tropical cyclone fix bulletins
表三 : 熱帶氣旋定位發佈
TPPN12 PGTW 071518 TXPQ25 KNES 071551 TPPN12 PGTW 072109 TXPQ25 KNES 072114 |
Last Accessed 最近訪問日期: Thu May 16 2024 22:54:20 HKT
Last Modified 最近修訂日期: Mon Jul 24 2023
