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1.
随着遥感技术在水体提取与监测方面的广泛应用,更多的研究者致力于提高遥感水体提取的精度。离散粒子群算法在遥感图像分类研究中获得了较高的精度和更稳健的分类效果,已经被应用到遥感水体提取领域,但其在水体提取中的适用性和精度还有待对比与验证。本文采用最新提出的2种基于离散粒子群算法的水体提取方法,即光谱匹配耦合离散粒子群算法（SMDPSO）与最大熵耦合离散粒子群算法（MEDPSO）,基于Landsat8_OLI遥感影像,分别选择了有冰雪、有云、有山体阴影和有建筑物的4种环境复杂,常规方法提取精度较低的区域进行水体提取,并与2种常用的水体指数法（NDWI、MNDWI）进行了对比与验证。结果表明：① SMDPSO和MEDPSO方法在4个实验区都能快速地寻找出最佳的水体分布,具有一定的通用性;NDWI和MNDWI方法对有冰雪、有云、有山体阴影和有建筑物影响的区域表现出水体信息的错分现象,提取精度较低;② SMDPSO方法能够识别细小河流和离散水体,水体提取精度较高,但在有冰雪、云、山体阴影和建筑物的复杂环境下提取精度较低、误判率高;MEDPSO方法不仅可以识别细小水体,而且也解决了其他3种方法在提取过程中无法抑制背景信息干扰的问题,在4个实验区的总体精度均在97.8%以上,高于其他3种方法;③ 将离散粒子群算法引入到水体提取方法之中,可增强方法的区域整体性,也可提高其水体提取的精度和自动化程度;④ 运用最大熵模型等机器学习方法,可以结合光谱、形状和纹理等影像信息以及地形信息来进行水体识别,使得水体信息提取精度更高。本文的研究可为离散粒子群算法的推广以及遥感水体提取方法的选择提供参考。 相似文献
2.
针对传统灰色模型在形变监测中数据序列拟合和预测精度不理想的情况,提出粒子群算法优化的分数阶算子EGM(1,1)模型。通过粒子群算法选择拟合EGM(1,1)平均相对误差最小的分数阶次,构建最优分数阶算子EGM(1,1)模型。用典型的变形监测数据验证优化模型,结果表明,优化模型对变形监测数据的拟合和预测都达到较高的精度,说明优化模型在变形监测数据的处理中具有可行性和有效性。 相似文献
3.
提出一种综合的多面函数参数自适应选取方法。该方法利用核函数阶数和平滑因子存在最优值以及核函数结点分布应符合高程异常变化趋势的特点,综合利用正交化算法选取核函数结点以及二维粒子群算法确定最佳阶数和平滑因子,实现多面函数参数的完全自适应选取。将该方法应用于地形起伏差异不同的2个测区,结果表明,相比传统经验性方法和部分参数自适应方法,该方法用于GPS高程拟合的精度和可靠性更高。 相似文献
4.
��������Ⱥ֧�������������ǵ��θ�����GPS�߳���� 总被引：1，自引：0，他引：1
?о?????????????????????GPS???????е?????????????????????????????????θ??????????μ??????????????????????????????????????????????????????????????????????SVM??????????????????????????????淨?????溯??????BP?????編???????????侫?????? 相似文献
5.
提出了基于s型生长曲线函数的地下水水质评价的污染损害率公式,并采用粒子群优化算法对水质污染损害率公式中的参数进行优化.将优化好的水质污染损害率公式用于某地20个采样点地下水水质评价,并与其它评价方法的评价结果进行了比较,结果表明公式能较好地用于地下水水质的综合评价,有明确的物理意义,简单适用,并具有一定的普适性. 相似文献
6.
Based on the field data acquired in the program of fast ice observation off Zhongshan Station, Prydz Bay, East Antarctica during the austral summer 2005/ 2006, physical properties evolution of fast ice during the ice ablation season is analyzed in detail. Results show that the annual maximum ice thickness in 2005 occurred in later November, and then ice started to reek, and the ablation duration was 62 days; sea water under the ice became warmer synchronously; corresponding to the warming sea ice temperature, a ＂relative cold mid-layer＂ appeared in sea ice; the fast ice marginal line recoiled back to the shore observably, and the recoil distance was 20.9 km from 18 December 2005 through 14 January 2006. In addition, based on the data of sea ice thickness survey along the investigation course of MV Xuelong on December 18 of 2005, the ice thickness distribution paten in the marginal ice zone have been described ： sea ice thickness increased, but the diversity of floe ice thick-ness decreased from open water to fast ice zone distinctly. 相似文献
7.
利用CryoSat-2卫星测高数据反演波弗特海的海冰厚度,并利用2010~2013年10月份仰视声呐(ULS)和2011年冰桥计划（IceBridge）数据对结果进行精度评估。结果表明,测高反演的海冰吃水深度与ULS吃水深度差值的最大值和标准差分别为14 cm和4 cm;测高反演的海冰厚度与冰桥计划海冰厚度差值的平均值和标准差分别为2.7 cm和65.7 cm,优于Laxon(2013)研究结果（分别优化2.1 cm和6.6 cm）。在此基础上,研究2011~2017年波弗特海夏冬两季的海冰厚度变化,发现二者具有类似的分布特征,且冬季3月海冰覆盖范围更广,厚度更大;进一步分析2011~2017年3月份冬季海冰厚度年际变化,发现其呈整体下降趋势,且2012年最小,2014年最大。 相似文献
8.
As an important component of the cryosphere,sea ice is very sensitive to the climate change.The study of the sea ice physics needs accurate sea ice thickness.This paper presents an electromagnetic-induction(EM) technique which can be used to measure the sea ice thickness distribution efficiently,and the successful application in Bothnian Bay.Based on the electromagnetic field theory and the electrical properties of sea ice and seawater,EM technique can detect the distance between the instrument and the ice/water interface accurately,than the sea ice thickness is obtained.Contrastive analysis of the apparent conductivity data obtained by EM and the value of drill-hole at same positions allows a construction of a transformable formula of the apparent conductivity to sea ice thickness.The verification of the sea ice thickness calculated by this formula indicates that EM technique is able to get reliable sea ice thickness with average relative error of only 12%.The statistic of all ice thickness profiles shows that the level ice distribution in Bothnian Bay was 0.4-0.6 m. 相似文献
9.
【目的】研究解决海洋大惯量浮式平台在复杂海况影响下所引起的振动冲击问题。【方法】采用逆运动学分析方法对平台回转位置进行优化研究,提出一种基于关节最小耗能的多目标轨迹优化算法。采用分段样条插值方法构造关节位置曲线,并建立关节能耗轨迹优化模型,采用粒子群算法实现对关节位置的优化搜索,从而得到基于平台转动最小耗能的位置优化轨迹。【结果与结论】所采用的轨迹优化方法能有效改善系统运行的平滑性,降低回转机构振动与冲击的影响程度,可为平台的振动与冲击主动控制提供必要的理论依据。 相似文献
10.
Sea ice thickness is one of the most important input parameters in the studies on sea ice disaster prevention and mitigation. It is also the most important content in remote sensing monitoring of sea ice. In this study, a practical model of sea ice thickness (PMSIT) was proposed based on the Moderate Resolution Imaging Spectroradiometer (MODIS) data. In the proposed model, the MODIS data of the first band were used to estimate sea ice thickness and the difference between the second-band reflectance and the fifth-band reflectance in the MODIS data was calculated to obtain the difference attenuation index (DAI) of each pixel. The obtained DAI was used to estimate the integrated attenuation coefficient of the first band of the MODIS at the pixel level. Then the model was used to estimate sea ice thickness in the Bohai Sea with the MODIS data and then validated with the actual sea ice survey data. The validation results showed that the proposed model and corresponding parameterization scheme could largely avoid the estimation error of sea ice thickness caused by the spatial and temporal heterogeneity of sea ice extinction and allowed the error of 18.7% compared with the measured sea ice thickness. 相似文献
11.
北极海冰对全球气候起着非常重要的调制作用,海冰范围是海冰监测的基本参数。近40年,北极地区持续变暖,北极海冰显著减少,进而引发北极自然环境恶化、北半球极端天气频发、全球海平面上升等一系列环境和气候问题。准确获取北极海冰范围及其演变趋势,确定海冰变化对全球气候系统的响应,是研究和预测全球气候变化趋势的关键之一。HasISST和OISST海冰数据集在海冰监测中应用最为广泛,可为北极地区长时间序列海冰变化研究提供基础数据,但这2套数据集空间分辨率相对较低,应用于北极关键区对中国气候响应研究方面存在很大的局限,为解决这一问题和弥补国内海冰监测微波遥感数据的空白,2011年6月27日,国家卫星气象中心（National Satellite Meteorological Center, NSMC）发布了FY（Fengyun, FY）北极海冰数据集,该数据集利用搭载在FY卫星上的微波成像仪（Microwave Radiation Imager, MWRI）数据,使用Enhance NASA Team算法制作,该算法利用前向辐射传输模型模拟北极地区4种海表类型（海水、新生冰、一年冰和多年冰）在不同大气条件下MWRI辐射亮温,进而得到每种大气条件下0~100%的海冰覆盖度查找表（海冰覆盖度每次增加1%）,通过观测值与模拟值的比对得到海冰覆盖度,由该数据集计算得到的北极海冰范围在大部分区域与实际情况相符。该产品虽已进行通道间匹配误差修正和定位精度偏差订正,但由于其搭载的微波成像仪（Microwave Radiation Imager, MWRI）天线长度有限,造成传感器探测到的地物回波信号相对较弱,难以区分海冰和近岸附近的陆地,影响了该数据集的精度和应用。为解决这一问题,本文基于美国冰雪中心（National Snow and Ice Data Center, NSIDC）发布的海冰产品对FY海冰数据集进行优化,NSIDC产品利用判断矩阵对海岸线附近的像元进行识别,并对误差像元进行不同程度的修正,由NSIDC产品计算得到的北极海冰范围与实际情况更为符合。数据集优化大大提高了FY海冰数据集的精度,研究结果表明,优化后FY海冰数据集与NSIDC产品相关系数高达0.9997,且二者日、月、年平均最大海冰范围偏差仅为3.5%、1.9%、0.9%,且FY海冰数据集优化过程对其较好的空间分异特征无明显影响。该数据集可正确地反映北极海冰范围及其变化情况,且海岸线附近海冰的分布情况更准确,可为北极海冰变化研究提供可靠的基础数据。 相似文献
12.
�����ƶ�������Ϸ�����GPS�߳�ת�� 总被引：1，自引：0，他引：1
????GPS????????????????????????????????з????????????????????趨????????????????е???????????????????????棬?????????????е?????????????????????????????????????????????????????????????????У?????н???GPS???????? 相似文献
13.
将微粒群优化算法与位错理论模型相结合,采用模拟重力测量数据反演断层三维滑动速率,并比较了该算法与蒙特卡洛法和蚁群算法的反演结果。利用河西地区2001~2004年的GPS数据,对祁连山断层的三维滑动速率进行反演,并与蚁群算法进行比较。结果表明,微粒群优化算法可有效求解断层的三维滑动速率,收敛快、精度高。 相似文献
14.
�ϲ���ά�������ʷ��ݵ��㷨�Ա� 总被引：1，自引：0，他引：1
?????????????λ????????????????????????????????????????????????????????????????????巨???????????????????ú???????2001~2004???GPS?????????????????????????????з????????????????б?????????????????????????Ч?????????????????????????????? 相似文献
15.
针对传统的RBF神经网络模型在GNSS高程拟合中拟合精度较低、稳定性较差、相关因子需提前人为设置等问题,通过将改进的自适应权重粒子群优化算法与MATLAB RBF神经网络函数newrb相结合,实现RBF神经网络函数模型中隐含节点数和SPREAD值的自动优化选取,提高算法在GNSS高程拟合中的精度和稳定性。通过实例分析,该方法拟合精度高,可达到mm级精度,相对于传统的二次多项式模型精度提高17%,稳定性良好。 相似文献
16.
以三峡库区秭归-巴东段为例,将地理加权回归(GWR)模型引入到研究区的空间尺度分割方法中,利用粒子群优化(PSO)算法对支持向量机(SVM)模型参数进行优化,构建GWR-PSO-SVM耦合模型,完成研究区滑坡易发性评价,并与传统的PSO-SVM耦合模型结果进行对比。结果表明,在特定类别精度分析、总体预测精度分析和曲线下面积分析中,本文方法评价效果均优于传统方法。 相似文献
17.
Effect of compressive strength on the performance of the NEMO-LIM model in Arctic Sea ice simulation
Satellite records show that the extent and thickness of sea ice in the Arctic Ocean have significantly decreased since the early 1970s. The prediction of sea ice is highly important, but accurate simulation of sea ice variations remains highly challenging. For improving model performance, sensitivity experiments were conducted using the coupled ocean and sea ice model (NEMO-LIM), and the simulation results were compared against satellite observations. Moreover, the contribution ratios of dynamic and thermodynamic processes to sea ice variations were analyzed. The results show that the performance of the model in reconstructing the spatial distribution of Arctic sea ice is highly sensitive to ice strength decay constant (Crhg). By reducing the Crhg constant, the sea ice compressive strength increases, leading to improved simulated sea ice states. The contribution of thermodynamic processes to sea ice melting was reduced due to less deformation and fracture of sea ice with increased compressive strength. Meanwhile, dynamic processes constrained more sea ice to the central Arctic Ocean and contributed to the increases in ice concentration, reducing the simulation bias in the central Arctic Ocean in summer. The root mean square error (RMSE) between modeled and the CryoSat-2/SMOS satellite observed ice thickness was reduced in the compressive strength-enhanced model solution. The ice thickness, especially of multiyear thick ice, was also reduced and matched with the satellite observation better in the freezing season. These provide an essential foundation on exploring the response of the marine ecosystem and biogeochemical cycling to sea ice changes.
相似文献18.
????????????????????????????????????????????б????????????????????????????????????????????????????????????????????????????????????????仯?????????仯???????????????????????????δ??????????????????????????????????????????仯????????????????????????е?????????????????????????????????????????????????????????????С???????????0.01??????????????????1???????????????????????????????Ч??????? 相似文献
19.
Calculation of photosynthetically available radiation using multispectral data in the Arctic 总被引：1，自引：0，他引：1
Photosynthetically Available Radiation(PAR) is an important bio-optical parameter related to marine primary production.PAR is usually measured by a broadband sensor and can also be calculated by multispectral data.When the PAR is calculated by multispectral data in polar region,four factors are possible error sources.PAR could be overestimated as the wavelengths of multispectral instrument are usually chosen to evade main absorption zones of atmosphere. However,both PARs calculated by hyperspectral and m... 相似文献
20.
����GPS���ݵ�����Ⱥ�㷨���ݶϲ���ά�������� 总被引：1，自引：1，他引：0
???????????λ????????????????????????????2001??2004???GPS????????????????????????????????з??????????????????????????Ч????????????????????????????????????????????н????????? 相似文献