本文關(guān)鍵詞：白令海及楚科奇海夏季水文結(jié)構(gòu)年際變化特征研究　出處：《上海海洋大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 白令海 楚科奇海 水團(tuán) 水文特征 凈熱通量 風(fēng)應(yīng)力旋度

【摘要】：北極是地球的冷源,在全球氣候系統(tǒng)中起著重要的調(diào)節(jié)作用。北極氣候在過(guò)去30多年正在發(fā)生快速變化,影響著全球尤其是北半球的環(huán)境和氣候。我國(guó)自1999年實(shí)施首次北極科學(xué)考察以來(lái),已完成了4個(gè)航次的北極科考,獲取大批有價(jià)值的科考數(shù)據(jù)。作為歷年北極科考重點(diǎn)海域的白令海與楚科奇海在地球氣候系統(tǒng)演變過(guò)程中有著相當(dāng)重要的作用。本文以白令海和楚科奇海的夏季水文結(jié)構(gòu)年際變化為重點(diǎn)展開研究,主要解決了以下問(wèn)題:一是基于2008年、2010年、2012年和2014年我國(guó)北極科學(xué)考察期間在白令海獲取的水文觀測(cè)數(shù)據(jù),通過(guò)對(duì)白令海B斷面溫鹽、水團(tuán)、上層海洋的熱含量分布進(jìn)行分析,探討了白令海水文結(jié)構(gòu)的年際變化特征。結(jié)果表明,(1)白令海夏季的水團(tuán)包括白令海上層水團(tuán)(BUW),中層水團(tuán)(BIW)、深層水團(tuán)(BDW)和白令海陸架水團(tuán)(BSW)。(2)白令海溫鹽分布差異最大、年際變化最劇烈的主要集中在上層水團(tuán)。(3)對(duì)比四年水團(tuán)分布情況,最明顯的變化是2012年7月調(diào)查區(qū)上層水溫度偏低,2014年7月上層海水溫度偏高,該年白令海冬季殘留水較其他年份淺50—70m。(4)這種異常變化在熱含量方面表現(xiàn)為,2012年7月調(diào)查區(qū)各個(gè)測(cè)站上的熱含量異常低,而2014年7月測(cè)站上的熱含量都高于平均水平。二是結(jié)合歷史共享資料,分析了白令海2008年、2010年、2012年及2014年7月凈熱通量變化、風(fēng)場(chǎng)及海平面氣壓分布等天氣特征,著重研究了2014年7月海溫偏高原因。結(jié)果表明,(1)夏季白令海整個(gè)海區(qū)都是獲得熱量的,大部分區(qū)域的凈熱通量在160~240 W·m~(-2)之間。(2)2014年7月白令海表層溫度偏高在陸架和海盆區(qū)分別為兩種不同的形成機(jī)制。陸架區(qū)主要是因?yàn)槔鄯e凈熱通量偏高,海水吸收熱量升溫造成;5~7月累積熱通量的偏高造成了2014年7月白令海陸架區(qū)海表溫度偏高。熱通量的變化對(duì)白令海海盆夏季水溫異常變化的貢獻(xiàn)不大,但是對(duì)陸架區(qū)有顯著的影響。(3)白令海2014年7月海盆區(qū)海溫偏暖是由于異常強(qiáng)且持久的海平面高壓以及負(fù)的風(fēng)應(yīng)力旋度風(fēng)場(chǎng)的共同作用。2014年5~7月,白令海海盆區(qū)異常強(qiáng)的海平面高壓一方面使得其西側(cè)的測(cè)站持續(xù)以偏南風(fēng)主導(dǎo),將南方的暖水輸送到該區(qū),加上累積凈熱通量的共同作用加熱表層海水;另一方面,使負(fù)的風(fēng)應(yīng)力旋度加強(qiáng),即白令海上層海洋的反氣旋式環(huán)流增強(qiáng),表層暖水通過(guò)Ekman抽吸輻合下沉加熱下層海水,造成該區(qū)冬季殘留水偏暖。三是基于2008年、2010年、2012年和2014年我國(guó)北極科學(xué)考察期間在楚科奇海獲取的水文觀測(cè)數(shù)據(jù),分析了楚科奇海C、R及SR斷面溫鹽分布與年際變化。結(jié)果表明,(1)C斷面溫鹽最突出的特征是:西部低溫高鹽,東部高溫低鹽。其中最南的C1斷面在167.5°W附近有顯著的溫鹽鋒面;北邊的C2斷面與南部斷面相比,整體溫度降低;層化顯著,在斷面西側(cè)有溫度低于0°C的冷水。再向北C3斷面,溫鹽層化顯著,底層出現(xiàn)溫度低于-1°C的高鹽水體。(2)R斷面的考察時(shí)間早過(guò)SR斷面1個(gè)月左右,比較溫鹽變化,發(fā)現(xiàn)回程觀測(cè)到的表層水溫大于去程觀測(cè)的溫度1℃左右;鹽度差異比溫度差別更大,回程觀測(cè)結(jié)果顯示表層有淡鹽水從表層向深層擴(kuò)散,深層水鹽度整體下降約1.5psu。四是系統(tǒng)分析了2008年、2010年、2012年及2014年北極科考調(diào)查區(qū)楚科奇海的表層溫鹽分布、水團(tuán)年際變化。結(jié)果表明,(1)楚科奇海表層海水溫度自南向北逐漸減小,東岸即阿拉斯加沿岸海域Hope角溫度要大于中部1~2℃,鹽度低于附近其他區(qū)域鹽度。(2)楚科奇海夏季水團(tuán)包括阿拉斯加沿岸水(ACW)、太平洋冬季水(PWW)、季節(jié)性冰融水(SMW)、大西洋水(AW)和楚科奇海夏季水(CSW)五種水體。其中,本文以-1.6℃為界將PWW細(xì)分為:新太平洋冬季水(NPWW)和冬季殘留水(RPWW);以-1.0℃為界將SMW細(xì)分為:早期季節(jié)性冰融水(ESMW)接近冰點(diǎn)和晚期季節(jié)性冰融水(LSMW)。(3)楚科奇海表層溫鹽存在明顯的時(shí)空變化。在太平洋水沿楚科奇海東部向北運(yùn)動(dòng)的過(guò)程中,表層水受融冰的影響,鹽度逐步降低,ACW與CSW相互作用,ACW范圍增大。PWW在2012年范圍最大,2014年調(diào)查期未觀測(cè)到PWW水團(tuán)。
[Abstract]:The Arctic is the cold source of the earth and plays an important role in the global climate system. The Arctic climate has been changing rapidly over the past 30 years, affecting the global environment and climate in the northern hemisphere, especially in the northern hemisphere. Since the implementation of the first Arctic scientific expedition in 1999, China has completed 4 voyages of the Arctic science examination to obtain a large number of valuable scientific data. As the key areas of the Arctic expedition of the Bering Sea and the Chukotka sea in the process of evolution of the earth's climate system plays an important role. In this paper, the summer hydrological structure the interannual variation of the Bering Sea and the Chukotka sea as the focus of research, mainly to solve the following problems: one is the observed hydrological data acquisition in the Bering Sea during 2008, 2010, 2012 and 2014 China's Arctic expedition based on through the heat content on the B section, the sea temperature and salinity, the upper ocean water masses the distribution is analyzed, to investigate the interannual variation of the structure of the Bering sea. The results show that (1) water masses in the Bering Sea in the summer of the Bering Sea water layer (BUW), intermediate water (BIW) and deep water (BDW) and the Bering Sea shelf water (BSW). (2) the Heuli distribution biggest difference and interannual variation of the most intense mainly concentrated in the upper water masses. (3) comparison of the four water distribution, the most obvious change is the low temperature upper water survey area in July 2014 July 2012, the upper water temperature is high, the Bering Sea in winter residual water than other years shallow 50 - 70m. (4) the abnormal change is shown in the aspect of heat content. The heat content of each station in July 2012 is extremely low, while the heat content in July 2014 is higher than the average level. Two, combined with historical shared data, we analyzed the characteristics of the net heat flux, the wind field and the sea level pressure distribution in the Bering Sea in 2008, 2010, 2012 and July 2014, and emphatically studied the reasons for the high sea surface temperature in July 2014. The results showed that (1) the whole sea area in the Bering Sea was obtained heat in summer, and the net heat flux in most areas was between 160~240 W m~ (-2). (2) the high surface temperature in the Bering Sea in July 2014 was two different formation mechanisms in the continental shelf and the basin. The continental shelf is mainly due to the high accumulation net heat flux and the absorption of heat by seawater. The high accumulated heat flux in 5~7 month caused the high sea surface temperature in the Bering Sea shelf area in July 2014. The change of heat flux has little contribution to the abnormal change of water temperature in the Bering Sea Basin in summer, but it has a significant influence on the shelf area. (3) the Bering Sea basin warm SST in July 2014 is due to the abnormal strong and persistent sea-level pressure and negative wind common action of stress curl wind field. 2014 5~7 months, the Bering Sea basin is strong high sea level on the west side of the station to continue its southerly warm water delivery will be dominant, South to the area, plus the cumulative net heat flux interaction of heating surface water; on the other hand, the negative wind stress curl strengthening namely, anti cyclonic circulation in the Bering Sea upper ocean enhanced surface warm water through the Ekman suction convergence caused by the heat sink lower water, winter warm water residue. Three is the hydrological observation data acquisition in the Chukotka sea during 2008, 2010, 2012 and 2014 China's Arctic expedition on the basis of the analysis of C, R and SR section thermohaline distribution and interannual variation of the sea of Chukotka. The results show that (1) the most prominent characteristics of the temperature and salt in the C section are low temperature and high salt in the West and high temperature and low salt in the East. The most southern C1 section has a significant temperature and salinity front near 167.5 degree W. The C2 section on the north side is lower than the southern section, and the overall temperature is reduced. The stratification is significant, and there is cold water below 0 degrees C on the west side of the section. North section of C3, temperature and salt significantly, underlying the emergence of high salt water temperature lower than -1 DEG C. (2) the effect of time earlier than the R section of the SR section for about 1 months, compared the temperature and salinity of the surface water temperature, found that the observed return to process greater than the observed temperature is about 1 DEG C; the salinity difference is much larger than the temperature difference, the observation results show the surface return light salt water from the surface to the deep salinity diffusion, deep the overall water decreased by about 1.5psu. The four is the system analysis in 2008, 2010, 2012 and 2014, the Arctic expedition survey area of Chukotka sea surface temperature and salinity distribution, interannual variation of water. The results show that (1) Chukotka sea surface water temperature gradually decreased from the south to the north, the east coast of Alaska coastal waters Hope angle is greater than the central temperature of 1~2 DEG C, the salinity is lower than that of other regions near the salinity. (2) the Chukotka sea in the summer water including Alaska coastal water (ACW), Pacific winter water (PWW), seasonal ice water (SMW), the Atlantic (AW) and the Chukotka sea in the summer of five water water (CSW). In this paper, based on the boundary of -1.6 C, PWW is subdivided into: new Pacific winter water (NPWW) and winter residual water (RPWW). At -1.0 C level, SMW is divided into: early seasonal ice melt water (ESMW), near freezing point and late seasonal ice melt water (LSMW). (3) significant spatio-temporal variation of Chukotka sea surface temperature and salt. In the process of sea water along the Pacific Chukotka northward movement, the surface water is affected by ice melting, salinity gradually reduced, ACW interacts with CSW and ACW increase. PWW in 2012 2014 the largest scope survey period was observed in PWW water.
【學(xué)位授予單位】：上海海洋大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：P731

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