本文關(guān)鍵詞：海洋鋒區(qū)海表風(fēng)速最小值與氣壓調(diào)整機(jī)制　出處：《南京信息工程大學(xué)》2016年碩士論文　論文類型：學(xué)位論文

  更多相關(guān)文章： 海洋鋒 氣壓調(diào)整機(jī)制 海表矢量風(fēng)速 最小值 背景氣壓場(chǎng)

【摘要】：利用AVHRR、QuickSCAT等高分辨率衛(wèi)星觀測(cè)資料和CFSR再分析資料,分析了墨西哥灣流區(qū)、東海黑潮鋒區(qū)、巴西—馬爾維納斯合流區(qū)和厄加勒斯回流區(qū)等全球主要海洋鋒區(qū)的大氣響應(yīng)特征,發(fā)現(xiàn)在上述海洋鋒區(qū)普遍存在海表矢量風(fēng)速最小值現(xiàn)象,并對(duì)這一現(xiàn)象的產(chǎn)生條件、形成機(jī)制和影響因子進(jìn)行了探討。研究指出：夏季(6-8)墨西哥灣流區(qū)、6月東海黑潮鋒區(qū)、全年巴西—馬爾維納斯合流區(qū)及厄加勒斯回流區(qū)海洋鋒附近有明顯的矢量風(fēng)速最小值現(xiàn)象。產(chǎn)生這一現(xiàn)象的條件為：海洋暖(冷)水區(qū)對(duì)應(yīng)于大氣高(低)壓區(qū)。其形成機(jī)制可用氣壓調(diào)整機(jī)制得到解釋：上述條件下,海洋鋒暖(冷)側(cè)上空之間產(chǎn)生的局地氣壓梯度與大尺度背景氣壓梯度方向接近相反,導(dǎo)致鋒區(qū)附近疊加后的氣壓梯度最小,海表風(fēng)速也因此最小。同時(shí),摩擦作用使海表風(fēng)偏向低壓一側(cè),于是沿鋒區(qū)走向(跨鋒區(qū)走向)的風(fēng)速分量差在暖水區(qū)一側(cè)產(chǎn)生氣旋性切變渦度(風(fēng)速輻合),進(jìn)而造成上升運(yùn)動(dòng)和強(qiáng)降水,而該分量差在冷水區(qū)一側(cè)則產(chǎn)生相反的大氣響應(yīng)特征。上述大氣響應(yīng)特征在日尺度下依然存在。鋒區(qū)海表風(fēng)速最小值現(xiàn)象在年際時(shí)間尺度上受海洋鋒強(qiáng)度和背景氣壓場(chǎng)強(qiáng)度的影響。在海洋鋒偏強(qiáng)年和背景氣壓場(chǎng)偏弱年,氣壓調(diào)整機(jī)制的結(jié)果使得鋒區(qū)海表風(fēng)速最小值現(xiàn)象更為明顯,海洋鋒偏弱年和背景氣壓場(chǎng)偏強(qiáng)年的情況則相反。鋒區(qū)海表風(fēng)速最小值現(xiàn)象雖然具有全球普適性,但其顯著性程度也呈現(xiàn)出區(qū)域和季節(jié)差異。整體而言,該現(xiàn)象在東海黑潮鋒區(qū)最為顯著,在巴西一馬爾維納斯合流區(qū)最弱；月尺度上,以6月巴西—馬爾維納斯合流區(qū)最為明顯,10月墨西哥灣流區(qū)最弱。
[Abstract]:Using the AVHRR reanalysis data and QuickSCAT high resolution satellite data and CFSR, analyzes the response of the Mexico Gulf region, the Kuroshio frontal zone, Brazil - Malvinas confluence zone and Agulhas recirculation zone and other major global ocean front region atmospheric characteristics, found in the sea front area common sea surface wind vector and the minimum phenomenon. For this phenomenon, the formation conditions are discussed and the mechanism of impact factor. The research points out: (6-8) the Mexico Gulf region in summer June, the Kuroshio in the East China Sea front zone, the Brazil - Mar Venus confluence phenomenon obviously near the minimum wind velocity vector and Agulhas recirculation zone ocean front. The condition of this phenomenon is that the Ocean warm (cold) water area corresponds to the high (low) pressure area of the atmosphere. The formation mechanism of the pressure adjusting mechanism has been available to explain: the above conditions, the ocean front warm (cold) generated over the side between the local pressure gradient and pressure gradient in the direction of large scale background nearly opposite, led to the near front zone of the superimposed pressure gradient minimum, sea surface wind speed due to the minimum. At the same time, the friction between the sea surface wind toward the low-pressure side, then along the frontal zone towards (to cross frontal) velocity components to generate cyclonic vorticity in the warm water side (wind speed convergence), causing the ascending motion and precipitation, and the component difference in cold water side has the opposite atmospheric response feature. The above atmospheric response features still exist on the diurnal scale. The minimum wind velocity in front sea surface is influenced by the strength of the ocean front and the background pressure field on the interannual time scale. In the weak year of the ocean front and the background pressure field, the result of the air pressure adjustment mechanism makes the phenomenon of the minimum value of the sea surface wind speed in the front area more obvious. Although the minimum value of wind velocity in front sea surface has global universality, its significant degree also shows regional and seasonal differences. Overall, this phenomenon in the East China Sea Kuroshio region is the most significant, in the Brazil Malvinas confluence zone weakest; the month scale, in June the Brazil Malvinas confluence zone is most obvious, in October the Mexico Gulf region.
【學(xué)位授予單位】：南京信息工程大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2016
【分類號(hào)】：P732
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本文編號(hào)：1344225