【摘要】：近幾十年來,由于大量的二氧化碳等溫室氣體排放到大氣中,使北極的海表溫度升高,海冰融化加速.海洋植物的活動產(chǎn)生的二甲基硫(DMS)排放到大氣中通過一系列變化會減弱溫室效應(yīng).本文研究的是巴倫支海(30°E-40°E,70°N-80°N),提取該區(qū)域2003-2009年的環(huán)境數(shù)據(jù)——冰蓋(ICE),風(fēng)速(WIND),云蓋(CLOUD),海表溫度(SST),葉綠素(CHL),混合層深度(MLD),MLD數(shù)據(jù)是通過北極的CTD數(shù)據(jù)計算得到的;2003-2005年的DMS的觀測數(shù)據(jù)是基于研究區(qū)域1998-2002年的歷史數(shù)據(jù)用BP神經(jīng)網(wǎng)絡(luò)時間序列模型預(yù)測得到的,并與用Simo提供的公式計算的DMS數(shù)據(jù)進(jìn)行比較;用遺傳算法校準(zhǔn)DMS模型中的參數(shù),得到該區(qū)域的最優(yōu)參數(shù)后,對這些參數(shù)進(jìn)行靈敏度檢驗;最后用CMIP5(5th Coupled Model Intercomparison Project)試驗中21×CO和24×CO的數(shù)據(jù),預(yù)測和比較DMS海氣通量的變化.本文得到的主要結(jié)論如下:從2004年開始冰蓋整體都有所下降,在2004-2007年的8月到9月,冰蓋均降到0%.在南部區(qū)域(30°E-40°E,70°N-75°N)的覆蓋率整年都很小,2005-2009年幾乎達(dá)到無冰區(qū)域.云蓋的月平均值一般都在80%以上,只有2004年的7月云蓋低至75.4%.風(fēng)速通常在7月達(dá)到最小值,約5m/s左右,冬季最大風(fēng)速達(dá)12.5m/s.SST最大值一般在8月達(dá)到,在這7年SST有下降的趨勢,2003年SST最大值為8.2℃,2009年最大值只有5.9℃.2009年CHL的峰值最大,約4mg/m3.MLD在秋季是最淺的,夏季次之,冬季較深,在1月和3月出現(xiàn)了“雙峰”現(xiàn)象.用BP神經(jīng)網(wǎng)絡(luò)預(yù)測得到的DMS的峰值在2004年最大,為11.77--12dumolm.與用Simo公式計算的DMS作為觀測值的校準(zhǔn)結(jié)果相比,用BP神經(jīng)網(wǎng)絡(luò)預(yù)測的數(shù)據(jù)作為觀測值的校準(zhǔn)結(jié)果較好.CHL峰值會先于DMS峰值8-16天,DMS海氣通量(DMS-Flux)和傳播速度(Kw)的峰值是在同一時間段達(dá)到的,浮游動物的峰值一般在7月達(dá)到.靈敏度檢驗表明:靈敏度最大的參數(shù)是代表浮游植物S(DMSP):N比例的γ,其次是代表細(xì)菌對DMS消耗率的28k.在24×CO情況下,SST、WIND、MLD相對于在21×CO下,分別增加了233.684%、22.744%、28.232%,ICE覆蓋率下降了11.986%,CLOUD變化不明顯,只下降了1.322%.在24×CO情況下,DMS海氣通量在有冰和無冰的情況下增長率分別為分別為148.840%、249.679%.本研究得到的結(jié)果對極地的生態(tài)環(huán)境與氣候的研究具有很好的參考價值.
[Abstract]:In recent decades, sea ice melting has accelerated due to large amounts of greenhouse gases, such as carbon dioxide, released into the atmosphere, causing the Arctic sea surface temperature to rise. The release of dimethyl sulfur (DMS) from the activity of marine plants into the atmosphere weakens Greenhouse Effect through a series of changes. In this paper, the environmental data of the Barents Sea (30 擄E-40 擄Elae 70 擄N-80 擄N),) from 2003 to 2009 are studied. The (ICE), wind speed of the ice sheet, (WIND), cloud cover (CLOUD), sea surface temperature (SST), chlorophyll (CHL), is studied in this paper. The mixing layer depth (MLD), MLD data are calculated by the Arctic CTD data. The observed data of DMS from 2003 to 2005 were predicted by using BP neural network time series model based on the historical data from 1998 to 2002 in the study area, and compared with the DMS data calculated by the formula provided by Simo. The parameters in the DMS model are calibrated by genetic algorithm, the optimal parameters in the region are obtained, and the sensitivity of these parameters is tested. Finally, the variation of sea and air fluxes of DMS is predicted and compared with the data of 21 脳 CO and 24 脳 CO in CMIP5 (5th Coupled Model Intercomparison Project) test). The main conclusions obtained in this paper are as follows: the whole ice sheet has declined since 2004, and from August to September of 2004-2007, the ice sheet has dropped to zero. The coverage in the southern region (30 擄E-40 擄EN 70 擄N-75 擄N) was very small throughout the year, and almost reached the ice-free area in 2005-2009. The monthly average of cloud cover is generally above 80 percent, only to reach 75.4 percent in July 2004. The wind speed usually reaches the minimum value in July, about 5m/s, and the maximum wind speed reaches the maximum value of 12.5m/s.SST in August in winter. In these 7 years, the maximum value of SST is 8.2 鈩，

本文編號：2346535