【摘要】：二類水體中水色三要素的光學(xué)特性對于建立水色遙感反演算法至關(guān)重要,長江河口水域由于受徑潮流相互作用和高含沙量影響,水體光學(xué)特性具有特殊性�；诂F(xiàn)場光學(xué)和同步水文數(shù)據(jù)分析了洪枯季長江河口地區(qū)水色要素隨著潮周期的變化特征。利用2014年5月和12月航次定點(diǎn)觀測數(shù)據(jù)的分析結(jié)果表明：總懸浮物濃度是影響長江口高渾濁水體遙感反射率的主導(dǎo)因素,枯季懸沙濃度分布范圍、變差和平均值都要高于洪季；無論洪枯季該地區(qū)葉綠素濃度都非常低,對遙感反射率的影響十分有限,其吸收系數(shù)很難通過現(xiàn)有實(shí)驗(yàn)方法準(zhǔn)確測出,在高濁度水體光譜特征中幾乎體現(xiàn)不出葉綠素對光譜反射率的影響,可以忽略不計；在分析了CDOM濃度和吸收系數(shù)模型的基礎(chǔ)上,發(fā)現(xiàn)CDOM吸收的時空變化較大,但來源基本一致。分析了三要素在長江口高濁度水域的光學(xué)效應(yīng)及其時空變化規(guī)律,發(fā)現(xiàn)在反演泥沙濃度時,口內(nèi)水域可以忽略CDOM和葉綠素的影響,而在口外水域必須剝離其影響。同一潮周期內(nèi)大潮時總懸浮顆粒物濃度最大能達(dá)到0.5kg/1113以上,而小潮時最大TSM濃度只有大潮的1/3,高總懸浮顆粒物濃度和潮周期內(nèi)較大的變差,使得很多經(jīng)驗(yàn)算法無法在該地區(qū)取得良好的效果。通過對三要素吸收特性的分析,以及與遙感反射率之間的相關(guān)性分析,可以發(fā)現(xiàn)口門內(nèi)外存在截然不同的固有光學(xué)特性,使得總懸浮顆粒物反演精度受到一定影響�；贚andsat8的波段設(shè)置,利用38組現(xiàn)場光學(xué)和同步水沙數(shù)據(jù)分析了長江河口地區(qū)總懸浮顆粒物濃度隨著潮周期的變化特征,比較了多種反演模式。結(jié)果表明：3S模型可以適用于長江口水域,實(shí)測數(shù)據(jù)驗(yàn)證大、小潮精度較其它模型更高,能更好地刻畫潮周期內(nèi)離水輻射的變化,反演總懸浮顆粒物濃度的潮周期變動。利用3S半分析模型,使用Landsat8紅光和紅外波段建立模型,能適應(yīng)長江口口內(nèi)不同潮情,在一定程度上可以剝離CDOM和葉綠素在總懸浮顆粒物濃度較低區(qū)域的影響,在口內(nèi)徐六涇站點(diǎn)實(shí)測數(shù)據(jù)驗(yàn)證相對誤差僅有9%。利用八景跨度為一年的Landsat8遙感影像,反演了長江口總懸浮顆粒物濃度,驗(yàn)證了3S算法在長江口地區(qū)的適用性,結(jié)果符合長江口地區(qū)懸沙的變化規(guī)律,可為上海市懸浮泥沙濃度監(jiān)測業(yè)務(wù)化運(yùn)行提供參考。
[Abstract]:The optical properties of the three elements of water color in the second kind of water body are very important for the establishment of the inversion algorithm of water color remote sensing. Due to the interaction of diameter tidal current and high sediment content, the optical characteristics of the water body in the estuary of the Yangtze River have its particularity. Based on the field optical and synchronous hydrological data, the variation characteristics of water color elements with tidal cycle in the Yangtze River estuary during the flood and dry season are analyzed. The results obtained from the fixed-point observation data in May and December 2014 show that the concentration of suspended sediment is the dominant factor affecting the remote sensing reflectance of high-turbidity water in the Changjiang Estuary, and the distribution range, variation and average value of suspended sediment concentration in the dry season are higher than those in the flood season. The chlorophyll concentration in this area is very low in flood and dry season, and the effect on remote sensing reflectivity is very limited. The absorption coefficient is difficult to be accurately measured by existing experimental methods. The effect of chlorophyll on spectral reflectance can be ignored in the spectral characteristics of high turbidity water body. Based on the analysis of CDOM concentration and absorption coefficient model, it is found that the absorption of CDOM varies greatly in time and space, but the sources are basically the same. The optical effects of the three elements in the high turbidity waters of the Yangtze River Estuary and their temporal and spatial variations are analyzed. It is found that the effects of CDOM and chlorophyll can be ignored in the water area of the mouth when the sediment concentration is retrieved, but the influence must be stripped off in the waters outside the mouth. In the same tidal cycle, the maximum concentration of total suspended particulates in the spring tide can reach above 0.5kg/1113, while the maximum TSM concentration in the low tide is only 1 / 3 of that of the spring tide, and the concentration of high total suspended particulate matter is worse than that in the tidal cycle. Many empirical algorithms can not achieve good results in this area. Through the analysis of the absorption characteristics of the three elements and the correlation analysis between the reflectivity and the remote sensing reflectivity, it can be found that there are distinct inherent optical properties inside and outside the entrance, which affects the retrieval accuracy of the total suspended particulates to a certain extent. Based on the band setting of Landsat8, the variation characteristics of total suspended particulate concentration with tidal cycle in the Yangtze River estuary are analyzed by using 38 sets of field optical and synchronous water and sediment data, and various inversion models are compared. The results show that the ratio 3s model can be applied to the Yangtze River Estuary. The measured data are verified greatly, the accuracy of the small tide is higher than that of the other models, and the variation of the off-water radiation in the tidal cycle can be better described, and the tidal period variation of the total suspended particulate concentration can be retrieved. By using 3s semi-analytical model and using Landsat8 red light and infrared band, the model can adapt to different tidal conditions in the mouth of the Yangtze River, and to some extent peel off the effects of CDOM and chlorophyll on the lower concentration of total suspended particulates. The relative error of data verification in Xuliujing station is only 9. Based on the Landsat8 remote sensing images with a span of one year, the total suspended particle concentration in the Changjiang Estuary is retrieved, and the applicability of the 3s algorithm in the Yangtze Estuary is verified. The results are in accordance with the law of suspended sediment in the Changjiang Estuary. It can provide reference for the operational operation of suspended sediment concentration monitoring in Shanghai.
【學(xué)位授予單位】：華東師范大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：X87

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本文編號：2158907