自由廣場》失事戰機的水下搜救

自由廣場》失事戰機的水下搜救

2017-11-17 06:00

◎ 歐錦昌

幻象失事業已數日,戰機連同駕駛員墜入東海的可能性似乎成為事實,如何將失事飛機定位成了目前最重要的工作。本人曾於一九九九年參與一架戰蒐直升機定位的工作,願將海域(水下)搜救經驗簡述,以供搜救單位參考。

民國八十八年,我國一架眼鏡蛇直升機墜入中部德基水庫,由於經過搜尋數日毫無結果,獲交通部及國防部的邀請,我與中華民國業餘無線電促進會(簡稱CTARL)中部分會同好施和夫、林憲一三人組成搜救小組前往新社,先聽取簡報再赴德基水庫,最終不負期望圓滿達成定位的任務。

由於當年網路尚未普及又網路搜尋工具缺乏而資訊難獲,因此搜救的過程並非順利,至失事現場再向製造商貝爾公司駐台代表要求提供進一步的資訊,才了解它的原理是利用音波(Acostic)工作,在新社得知該眼鏡蛇(Cobra)在向美方購買時裝備有特低頻/低頻(VLF/MF)波段的警報信號發射器,這個頻段其實就是目前所有潛艦國家發送指令給航行於大海中潛艦的頻段,這個頻段在水中具有最佳的傳導特性。其頻率是由聯合國ITU/IMO/ICAO共同律定的37.5Khz(卅七.五千赫),正常的搜救單位(海軍搜救大隊及相關的運用單位)應連同購置尋標器時就需同時建立。這種發報器有個專有名詞稱「Pinger」,通常會固定在飛航資料記錄器上。航空器在發生事故墜入水中時,該發報器兩個電極在浸水後就會導通,開始以每秒一次的間隔發出如機械式時鐘「塔、塔、塔」之信號,如果電池是滿格情況下會有一個月工作的時效,其發送深度可達三千英尺,因此只要戰機不要滾入海溝或是發報器失效的情況下,本次失事海域其深度大約在一百公尺左右,信號應該相當強。當年德基水庫約有七十五公尺的深度,在搜獲時,接收機的信號強度就非常的強大,那也是人類首次在高山湖泊中聽到Pinger所發出的信號。

報導中曾指民航機的駕駛員報告在121.5Mhz收到警報信號,那就代表是由水上的航行物或是失事的殘存艇、筏,或是座艙椅所發出,不會是由水下的物體所產生,因為所有水下所發出的電波馬上經由海水的導通而無法向空間傳播,Pinger是利用電波轉換成機械波,再利用接收器從機械波還原成可接收的信號。上述聯合國的單位在二○○二年前是以民航機121.5Mhz、軍用航空器243Mhz在失事或緊急時發出警報信號(Alert Signal),交互發射,但並未帶出失事船舶或航空器的資訊(國別、識別碼等),二○○二年以後稱EPIRB(船)、ELT(航空器)、PLB(個人),並帶有相關的資料,它們是發向在太空中的低軌道衛星,工作於406.1Mhz,其搜救總部設在倫敦,目前的航空器及船舶並無法接收及解碼。因此,研判121.5Mhz是人為的因素較大,其原因是這類121.5/243Mhz的裝備部分尚在漁船及商船中,所發出的聲響就像極了救護車的警報聲,而且每架航空器在開航後依規定應守值121.5兆赫(航空遇險頻道),本人還真願意相信是從子雨的彈射椅所發出,它的發射範圍大約在二百公里的範圍,同時也可工作卅天左右。但個人的經驗認知應該是海域中作業的船隻誤觸或是惡意發出,因這類非屬新型的ELT並沒有帶出其船舶識別碼。

在利用Pinger接收器(Pinger receiver)在海域搜尋時應注意到下列的因素:由於工作於超音波的範圍,因此在附近活動的鯨豚間的呼叫聲、本身船舶推進器或是經過船舶所產生的水泡都會產生假信號干擾到接收器而產生誤判。另外,迴聲探測器(Echo Sounder,或稱測深儀、漁探機等)、主動式聲納等應暫停工作。如果利用移動的接收器應將傳導器放置在船頭靠近中段前緣之位置,特別在大浪中數千噸以下的船舶船頭會被抬起讓傳導器(Transducer)失去效用,又利用拖曳式的接收機在大浪中操作有其不利處,通常製造商會建議用小艇來作拖曳,但冬季海象的因素下作業相當困難,同時接收極微弱信號的經驗是成功的條件,這種經驗就應該於平時加以嚴格的訓練,當在寬闊海域操作接收機,發射源擦身而過,其信號強度有可能就是在雜訊與最弱可判讀的強度附近而重疊在一起。參與作業的艦艇應參考國際海事組織(IMO)所制定的船舶海難搜救手冊進行組織及搜尋。同時建議海巡署大型巡防艦應於造艦時在船底裝設37.5Khz的傳導器並連同購置接收器,以及部分的拖曳式Pinger接收器。

七日夜晚當知道子雨所駕的幻象戰機失聯的消息後,內心充滿期待他能安然的渡過難關,他就像我們孩子般的年齡但成就非凡已擔負保衛領空的重責,但隨著時間的消逝,我也曾在海上工作超過卅年,知道在這個季節那個海域的海象現實狀況。如果真的已發生不幸,也盼望子雨的英靈能乘著季風從東海魂歸故里。

(作者為前CTARL法規主委、前海巡署洋總局組主任)

NASA Satellites Watch Earth ‘Breathe’ in Awesome Time-Lapse Video

NASA Satellites Watch Earth ‘Breathe’ in Awesome Time-Lapse Video

A cool new time-lapse video of Earth reveals how our planet has changed over the last two decades as NASA satellites continuously monitored the populations of plant life on land and in the oceans.

The video shows Earth “breathing” repetitiously as the seasons change throughout each year, with snow coverage on the North and South Poles periodically growing and shrinking while green regions of vegetation do the same.

A NASA visualization shows 20 years of continuous satellite observations of plant life on land and at the ocean's surface from 1997 to 2017. Vegetation on land is represented on a scale from brown (low vegetation) to dark green (lots of vegetation). In the ocean, populations of phytoplankton are indicated on a scale from purple (low) to yellow (high).

A NASA visualization shows 20 years of continuous satellite observations of plant life on land and at the ocean’s surface from 1997 to 2017. Vegetation on land is represented on a scale from brown (low vegetation) to dark green (lots of vegetation). In the ocean, populations of phytoplankton are indicated on a scale from purple (low) to yellow (high).

Credit: NASA

Meanwhile, clouds of microscopic phytoplankton, a type of algae, bloom on the ocean’s surface, where the tiny organisms turn water and carbon dioxide into oxygen and sugar as they bask in sunlight. [Earth’s Plant Life from Space in Photos: NASA Satellite Images]

“These are incredibly evocative visualizations of our living planet,” Gene Carl Feldman, an oceanographer at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, said in a statement. “That’s the Earth, that is it breathing every single day, changing with the seasons, responding to the sun, to the changing winds, ocean currents and temperatures.”

The SeaWiFS satellite, launched in 1997, measures the amount of phytoplankton that blooms on Earth's ocean surfaces. Here, SeaWiFS data show how phytoplankton in the eastern equatorial Pacific Ocean responded to the transition between El Niño and La Niña conditions in 1998. Higher concentrations of phytoplankton are represented in yellow and red, with lower concentrations pictured in purple.

The SeaWiFS satellite, launched in 1997, measures the amount of phytoplankton that blooms on Earth’s ocean surfaces. Here, SeaWiFS data show how phytoplankton in the eastern equatorial Pacific Ocean responded to the transition between El Niño and La Niña conditions in 1998. Higher concentrations of phytoplankton are represented in yellow and red, with lower concentrations pictured in purple.

Credit: NASA

The visualization was created using data from Earth-observing satellites like NASA’s Sea-viewing Wide Field-of-view Sensor (SeaWiFS) mission, which began collecting global ocean data in 1997, as well the space agency’s Terra, Aqua and Suomi NPP weather satellites.

Seeing how plant life all around the planet has changed over the last 20 years can help scientists and researchers investigate how ecosystems are responding to changing environmental conditions, NASA officials said in the statement.

For example, studies have shown that rising sea surface temperatures have impeded growth of phytoplankton, which means that there are fewer organisms in the ocean to remove carbon dioxide, a greenhouse gas that is the main driver of climate change.

Vegetation in North America wakes up in the spring, captured here as a change from pale green to dark green as photosynthesis ramps up with the season. White areas are covered in snow.

Vegetation in North America wakes up in the spring, captured here as a change from pale green to dark green as photosynthesis ramps up with the season. White areas are covered in snow.

Credit: NASA

“The space-based view of life allows scientists to monitor crop, forest and fisheries health around the globe. But the space agency’s scientists have also discovered long-term changes across continents and ocean basins,” NASA officials said. “As NASA begins its third decade of global ocean and land measurements, these discoveries point to important questions about how ecosystems will respond to a changing climate and broad-scale changes in human interaction with the land.”

Email Hanneke Weitering at hweitering@space.com or follow her @hannekescience. Follow us @SpacedotcomFacebook and Google+. Original article on Space.com.

火星男孩再提拿破崙東方雄獅甦醒說,是指中國將雄霸世界嗎?

火星男孩再提拿破崙東方雄獅甦醒說,是指中國將雄霸世界嗎?
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物理大師霍金認為火星男孩的確不是地球人,因為他說出的事超乎很多科學家想像。火星男孩現已是20歲的火星青年,他又提到拿破崙說過的東方雄獅正在甦醒,並直指就是中國!
火星男孩並指出過去沒人注意的埃及金字塔八千多粒穀子的秘密,原來五千年前埃及法老就知道中國將擔負起人類絕續的重責大任!
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