本文關鍵詞：基于GOCI影像的太湖水體漫衰減系數(shù)遙感估算研究　出處：《南京師范大學》2015年碩士論文　論文類型：學位論文

  更多相關文章： 遙感 漫衰減系數(shù) 估算模型 GOCI影像 太湖

【摘要】：漫衰減系數(shù)Kd (Diffuse Attenuation Coefficient)是水體光學中的一個重要參數(shù),也是水生態(tài)系統(tǒng)的重要影響因素。水體漫衰減系數(shù)的遙感估算,能夠揭示區(qū)域水體光場的變化,對水質及水生態(tài)環(huán)境監(jiān)測具有重要意義。本研究以太湖為研究對象,根據(jù)不同季節(jié)太湖地面遙感實驗的實測數(shù)據(jù),分析了太湖水體的表觀光學特性和固有光學特性,同時分析了水體各組分的吸收系數(shù)和后向散射系數(shù)對漫衰減系數(shù)的貢獻率,確定漫衰減系數(shù)的影響因子,然后基于GOCI波段設置構建太湖水體漫衰減系數(shù)估算經(jīng)驗模型和半分析模型,分析對比模型的精度,將最優(yōu)模型應用于GOCI影像,估算得到太湖全湖水體漫衰減系數(shù),進而分析太湖水體漫衰減系數(shù)的時空變化特征。論文主要得出以下結論：(1)太湖漫衰減系數(shù)影響因子490 nm處漫衰減系數(shù)的主要影響因子是非色素顆粒物的吸收系數(shù),其貢獻率遠遠高于其他影響因子,色素顆粒物吸收系數(shù)的貢獻率位居第二,后向散射系數(shù)和CDOM吸收系數(shù)對漫衰減系數(shù)的貢獻相對較小,其中后向散射的貢獻率大體上高于CDOM吸收的貢獻率。(2) GOCI數(shù)據(jù)漫衰減系數(shù)估算模型GOCI第7波段可以突出懸浮物的特征信息,將其引入到經(jīng)驗模型中,可以很好地提高太湖漫衰減系數(shù)估算模型的精度。GOCI第4、5、7波段即近紅外波段、紅波段和綠波段的組合模型Kd(490)=436.581R745+290.84R660-448.66 R555+6.970精度最高,模型擬合結果R2為0.737,驗證結果平均相對誤差和均方根誤差分別為28.6%和1.495,并且模型對漫衰減系數(shù)的變化敏感性不強,具有較高的普適性。半分析模型估算精度很大程度上依賴于固有光學量的估算精度,基于實測固有光學量構建的半分析模型精度相對較高,基于QAA和Doron方法估算固有光學量構建的半分析模型估算結果出現(xiàn)較大誤差。將所構建的最優(yōu)經(jīng)驗模型運用到GOCI影像估算太湖漫衰減系數(shù),利用同步地面觀測結果進行檢驗,結果表明該經(jīng)驗模型具有較高的估算精度和較好的普適性,是比較適合GOCI影像數(shù)據(jù)的太湖水體漫衰減系數(shù)估算模型。(3)太湖水體漫衰減系數(shù)時空變化特征利用2013年5月14日、2014年8月5日和2014年10月24日的GOCI影像,對太湖從上午8點到下午3點的漫衰減系數(shù)進行估算,綜合不同日期太湖水體漫衰減系數(shù)空間分布及日變化特征分析的結果,總體來說太湖水體漫衰減系數(shù)值域主要分布在0～15m-1,大體可以分為三個等級,低值區(qū)值域分布在0～4m-1,中值區(qū)值域分布在4～8m-1,高值區(qū)主要分布在8～15m-1,少部分湖區(qū)高于15m-1。太湖水體漫衰減系數(shù)存在一定的時空差異性。從空間上來說,太湖水體漫衰減系數(shù)呈現(xiàn)一定的梯度性,即從東部到西部逐漸變高,呈現(xiàn)西部高于東部的趨勢。從時間上來說,不同日期太湖水體漫衰減系數(shù)的日變化呈現(xiàn)出相似的規(guī)律性,即早上太湖漫衰減系數(shù)相對較高,之后隨著時間變化大體上呈現(xiàn)逐漸降低的趨勢。
[Abstract]:Diffuse attenuation coefficient (KD) Diffuse Attenuation coefficient is an important parameter in water optics. The remote sensing estimation of water diffuse attenuation coefficient can reveal the variation of regional water light field. This study takes Taihu Lake as the research object, according to the ground remote sensing data of Taihu Lake in different seasons. The apparent sightseeing characteristics and intrinsic optical properties of Taihu Lake were analyzed, and the contribution rate of absorption coefficient and backscattering coefficient to diffuse attenuation coefficient were analyzed, and the influence factors of diffuse attenuation coefficient were determined. Then the empirical model and semi-analytical model are constructed based on the GOCI band setting to estimate the diffuse attenuation coefficient of Taihu Lake. The accuracy of the model is analyzed and the optimal model is applied to the GOCI image. The water mass diffuse attenuation coefficient of Taihu Lake is estimated. Furthermore, the temporal and spatial characteristics of the diffuse attenuation coefficient of Taihu Lake are analyzed. The following conclusions are drawn in this paper: 1). Diffuse attenuation coefficient of Taihu Lake the main influence factor of diffuse attenuation coefficient at 490 nm is the absorption coefficient of non-pigment particles. The contribution rate was much higher than other factors, the contribution rate of pigment particulate absorption coefficient was the second, backscattering coefficient and CDOM absorption coefficient had relatively little contribution to diffuse attenuation coefficient. The contribution rate of backscattering is generally higher than that of CDOM absorption. 2) the diffuse attenuation coefficient estimation model of GOCI data can highlight the characteristic information of suspended matter in band 7 of GOCI. By introducing it into the empirical model, the accuracy of the estimation model of the diffuse attenuation coefficient of Taihu Lake can be improved very well. The combination model of red band and green band Kd(490)=436.581R745 290.84R660-448.66R555 6.970 has the highest precision. The model fitting result R2 is 0.737, the average relative error and root mean square error are 28.6% and 1.495respectively, and the model is not sensitive to the change of diffuse attenuation coefficient. The estimation accuracy of semi-analytical model depends on the estimation accuracy of intrinsic optical quantity to a great extent, and the semi-analytical model based on measured intrinsic optical quantity has a relatively high accuracy. The estimation results of the semi-analytical model based on the QAA and Doron methods to estimate the intrinsic optical quantities have a large error. The best empirical model is applied to estimate the diffuse attenuation coefficient of Taihu Lake in the GOCI image. The results of synchronous ground observation show that the empirical model has higher estimation accuracy and better universality. It is a model for estimating the diffuse attenuation coefficient of Taihu Lake, which is more suitable for GOCI image data.) the temporal and spatial variation characteristics of the diffuse attenuation coefficient of Taihu Lake are used in May 14th 2013. The diffuse attenuation coefficients of Taihu Lake from 8 am to 3 pm were estimated by GOCI images on August 5th 2014 and October 24th 2014. According to the results of spatial distribution and diurnal variation analysis of the diffuse attenuation coefficient of Taihu Lake on different dates, the range of diffuse attenuation coefficient of Taihu Lake water body is mainly distributed in 0 ~ 15m ~ (-1), which can be divided into three grades. The range of the low value region is 0 ~ 4m ~ (-1), the median region is 4 ~ 8m ~ (-1), and the high value region is mainly 8 ~ (15) m ~ (-1). A few lakes are higher than 15m ~ (-1). There are some spatial and temporal differences in the diffuse attenuation coefficient of Taihu Lake water body. In space, the diffuse attenuation coefficient of Taihu Lake water body presents a certain gradient, that is, from the east to the west, the water body diffuse attenuation coefficient gradually becomes higher. From the time point of view, the diurnal variation of the overspread attenuation coefficient of Taihu Lake on different dates showed a similar regularity, that is, the diffuse attenuation coefficient of Taihu Lake in the morning was relatively high. Then, with the change of time, the trend is gradually decreasing.
【學位授予單位】：南京師范大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：X87

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本文編號：1424587