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Effect of random phase error and baseline roll angle error on eddy identification by interferometric imaging altimeter

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Journal of Oceanology and Limnology 2022年第5期40卷 1881-1888页

作者： Le GAO Hanwei SUN Jifeng QI Qiufu JIANG CAS Key Laboratory of Ocean Circulation and Waves Institute of OceanologyChinese Academy of Sciences and Center for Ocean Mega-ScienceChinese Academy of SciencesQingdao 266071China Beijing Radio Measurement Institute Beijing 100854China Pilot National Laboratory for Marine Science and Technology(Qingdao) Qingdao 266237China

To achieve better observation for sea surface,a new generation of wide-swath interferometric altimeter satellites is *** satellite launch,it is particularly important to study the data processing methods and carry out the detailed error analysis of ocean satellites,because it is directly related to the ultimate ability of satellites to capture ocean *** this purpose,ocean eddies are considered a specific case of ocean signals,and it can cause significant changes in sea surface *** is suitable for theoretical simulation of the sea surface and systematic simulation of the *** analyzed the impacts of random error and baseline error on the sea surface and ocean signals and proposed a combined strategy of low-pass filtering,empirical orthogonal function(EOF)decomposition,and linear fitting to remove the *** this strategy,sea surface anomalies caused by errors were considerably improved,and the capability of satellite for capturing ocean information was ***,we found that the baseline error in sea surface height data was likely to cause inaccuracy in eddy boundary detection,as well as false eddy *** abnormalities could be prevented for"clean"sea surface height after the errors removal.

关键词： interferometric altimetry baseline error random error ocean eddy theoretical and systematic simulation error removal strategy

Estimation of random errors for lidar based on noise scale factor

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Chinese Physics B 2015年第8期24卷 386-390页

作者：王欢雪刘建国张天舒 University of Chinese Academy of Sciences Key Laboratory of Environment Optics and Technology Anhui Institute of Optics and Fine Mechanics Chinese Academy of Sciences

Estimation of random errors, which are due to shot noise of photomultiplier tube(PMT) or avalanche photodiode(APD) detectors, is very necessary in lidar observation. Due to the Poisson distribution of incident electrons, there still exists a proportional relationship between standard deviation and square root of its mean value. Based on this relationship,noise scale factor(NSF) is introduced into the estimation, which only needs a single data sample. This method overcomes the distractions of atmospheric fluctuations during calculation of random errors. The results show that this method is feasible and reliable.

关键词： atmospheric optics lidar random error noise factor noise scale factor

EFFECTS OF random errorS ON THE SIDELOBE FOR THE LINEAR ARRAY

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Journal of Electronics(China) 2002年第1期19卷 81-83页

作者： Cheng Gang Lin Wei Lin Shiming(Northwestern Polytechnical University, Xi’an 710072) (Japan Micro Systems Co., Osaka 530-0001, Japan) Northwestern Polytechnical University Xi'an 710072 Japan Micro Systems Co. Osaka 530-0001 Japan

The effects of statistically dependent random errors on the sidelobe are analyzed for the linear array. It is shown that the random errors cause a rise in the sidelobe level. The simple formulas can also be obtained f... 详细信息

关键词： Linear array Sidelobe random error Correlation moment

Potential of geosynchronous SAR interferometric measurements in estimating three-dimensional surface displacements

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Science China(Information Sciences) 2017年第6期60卷 48-61页

作者： Wanji ZHENG Jun HU Wei ZHANG Changjiang YANG Zhiwei LI Jianjun ZHU School of Geosciences and Info-Physics Central South University National Disaster Reduction Center Ministry of Civil Affairs of the People's Republic of China

The ability of differential interferometric synthetic aperture radar(DIn SAR) technology used for centimeter level deformation detection has been well-proved. Nevertheless, the applications of DIn SAR under the low Earth orbit(LEO) are limited to the line-of-sight(LOS) measurements, the limited observation area and the long revisited time. Geosynchronous SAR(GEO SAR), which runs in the height of 36000 km with the advantage of a short revisit time and a large observation area, is a potential approach to overcome the series problems in LEO SAR. This paper focuses on estimating three-dimensional(3D) displacements by using GEO SAR DIn SAR measurements acquired from multiple imaging geometries. Aiming to provide a normal solution for geologic hazard monitoring and relative geophysical application in the future, the errors induced by decorrelation noise, orbital ramp and ionospheric distortion are analyzed for the GEO SAR DIn SAR measurements. A series of experiments have been conducted to find the relationship between the 3D displacements and the DIn SAR observations which are provided with different noises and combinations of imaging geometries. The results reveal that 3D displacements can be expected from the combination of left-and right-looking GEO SAR DIn SAR measurements. In particular, the north-south solution can achieve centimeter and even millimeter level.

关键词： GEOSAR 3D displacements DInSAR IGSO random error systematic error

Intercomparison of GPS radiosonde soundings during the eastern tropical Indian Ocean experiment

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Acta Oceanologica Sinica 2014年第1期33卷 127-134页

作者： XIE Qiang HUANG Ke WANG Dongxiao YANG Lei CHEN Ju WU Zewen LI Daning LIANG Zhiyan State Key Laboratory of Tropic Oceanography South China Sea Institute of Oceanology Chinese Academy of Sciences Sanya Institute of Deep-sea Science and Engineering Chinese Academy of Sciences University of Chinese Academy of Sciences Xisha and Nansha Abyssal Marine Environmental Research Station South China Sea Institute of Oceanology Chinese Academy of Sciences Guangzhou Meteorological Observatory

Temperature and relative humidity profiles derived from two China-made global positioning system（GPS） radiosondes（GPS-TK and CF-06-A） during the east tropical Indian Ocean（ETIO） experiment were compared with Vaisala RS92-SGP to assess the performances of China-made radiosondes over the tropical *** results show that there have relative large biases in temperature observations between the GPSTK and the RS92-SGP in the low troposphere,with a warm bias of greater than 2 K in the day and a cooling bias of 0.6 K at *** temperature differences of the CF-06-A were small in the troposphere both in daytime and nighttime,and became large peak-to-peak fluctuations in the *** intercomparison of the relative humidity showed that the CF-06-A had large random errors due to the limitation of sensors and the lack of correction scheme,and the GPS-TK had large systematic biases in the low troposphere which might be related to the temperature *** height measurements are clearly suitable for China-made radiosonde systems *** night,the CF-06-A and the GPS-TK could provide virtual potential temperature and atmospheric boundary layer height measurements of suitable quality for both weather and climate *** a result of the intercomparison experiment,major errors in the Chinamade radiosonde systems were well indentified and subsequently rectified to ensure improving accuracy for historical and future radiosondes.

关键词： global positioning system radiosonde temperature and relative humidity profile systematic bias random error tropical ocean

error Sensitivity Analysis in 10–30-Day Extended Range Forecasting by Using a Nonlinear Cross-Prediction error Model

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Journal of Meteorological Research 2017年第3期31卷 567-575页

作者： Zhiye XIA Lisheng XU Hongbin CHEN Yongqian WANG Jinbao LIU Wenlan FENGl college of resources and environment chengdu university of information technologyChengdu 610225 plateau atmosphere and environment key laboratory of sichuan province Chengdu 610225 key laboratory of middle atmosphere and global environment observation institute of atmospheric physicschinese academy of sciencesBeijing 100029

Extended range forecasting of 10-30 days, which lies between medium-term and climate prediction in terms of timescale, plays a significant role in decision-making processes for the prevention and mitigation of disastrous met- eorological events. The sensitivity of initial error, model parameter error, and random error in a nonlinear cross- prediction error （NCPE） model, and their stability in the prediction validity period in 1 0-30-day extended range fore- casting, are analyzed quantitatively. The associated sensitivity of precipitable water, temperature, and geopotential height during cases of heavy rain and hurricane is also discussed. The results are summarized as follows. First, the initial error and random error interact. When the ratio of random error to initial error is small （10＂5-10-2）, minor vari- ation in random error cannot significantly change the dynamic features of a chaotic system, and therefore random er- ror has minimal effect on the prediction. When the ratio is in the range of 10-1-2 （i.e., random error dominates）, at- tention should be paid to the random error instead of only the initial error. When the ratio is around 10 2-10-1, both influences must be considered. Their mutual effects may bring considerable uncertainty to extended range forecast- ing, and de-noising is therefore necessary. Second, in terms of model parameter error, the embedding dimension m should be determined by the factual nonlinear time series. The dynamic features of a chaotic system cannot be depic- ted because of the incomplete structure of the attractor when m is small. When m is large, prediction indicators can vanish because of the scarcity of phase points in phase space. A method for overcoming the cut-off effect （m 〉 4） is proposed. Third, for heavy rains, precipitable water is more sensitive to the prediction validity period than temperat- ure or geopotential height; however, for hurricanes, geopotential height is most sensitive, followed by precipitable water.

关键词： extended range forecasting random error initial error model parameter error sensitivity

A Report on a Biotite-Calcic Hornblende Geothermometer

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Acta Geologica Sinica(English Edition) 2002年第1期76卷 126-131页

作者：吴春明潘裕生王凯怡张健 Institute of Geology Chinese Academy of Geological Sciences Beijing 100037 Institute of Geology and Geophysics Chinese Academy of Sciences Beijing 100029 Department of Earth Sciences The Graduate School Chinese Academy of Sciences Beijing 100039

This paper presents a biotite-calcic hornblende geothermometer which wasempirically calibrated based on the garnet-biotite geothermometer and thegarnet-plagioclase-hornblende-quartz geobarometer, in the ranges of 560-800 deg C (T) and 0.26-l.4GPa (P) using the data of metadolerite, amphibolite, metagabbro, and metapelite collected from theliterature. Biotite was treated as symmetric Fe-Mg-Al^VI-Ti quaternary solid solution, and calcichornblende was simplified as symmetric Fe-Mg binary solid solution. The resulting thermometer mayrebuild the input garnet-biotite temperatures well within an uncertainty of + - 50 deg C. errors of+- 0.2 GPa for input pressure, along with analytical errors of = - 5 percent for the relevantmineral compositions, may lead to a random error of + - 16 deg C for this thermometer, so that thethermometer is almost independent of pressure estimates. The thermometer may clearly discriminatedifferent rocks of lower amphibolite, upper amphibolite and granulite facies on a high confidencelevel. It is assumed that there is a ferric iron content of 11.6 percent in biotite, and that theiron content in calcic hornblende may be calculated according to the method of Dale et al. (2000).This thermometer can be used for medium- to high-grade metabasites and metapelites.

关键词： biotite-calcic hornblende geothermometer calibration random error application

A PARAMETRIC METHOD OF SITE error ESTIMATION FOR A LIGHTNING LOCATION SYSTEM

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Acta meteorologica Sinica 1991年第3期5卷 370-380页

作者：陈明理刘欣生郭昌明葛正谟 Lanzhou Inst. of Plateau Atmospheric Physics Academia Sinica Lanzhou China China

In this paper,a parametric method of site error estimation is developed for a lightning location system (LLS) which consists of three or more direction finders (DFs) and one position analyzer (PA). The site error for each DF is a function of bearings measured by the DF, and is assumed to be limited-term harmonics. The problem of site error estimation is reduced to a non-linear unconstrained minimization problem by employing the eigen technique (Orville Jr., 1987). The site error can be found directly by minimizing the objective function. By using the data set obtained with the LLS of three DFs in Beijing area during the summer of 1988, the site error correction curves for all DFs were found. About 4900 lightning flashes detected by the three DFs were used. The results showed that about 95% of the flash residuals of the sample were within ± 1 degree after corrections. The lightning locations with site error corrections were more consistent with the corresponding radar echoes than those without corrections.

关键词： lightning location system random error site error

Assessment of the State of Forests Based on Joint Statistical Processing of Sentinel-2B Remote Sensing Data and the Data from Network of Ground-Based ICP-Forests Sample Plots

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Open Journal of Ecology 2022年第8期12卷 513-528页

作者： Alexander S. Alekseev Dmitry M. Chernikhovskii Department of Forest Inventory Management and GIS Saint-Petersburg State Forest Technical University Saint-Petersburg Russian Federation

The research was carried out on the territory of the Karelian Isthmus of the Leningrad Region using Sentinel-2B images and data from a network of ground sample plots. The ground sample plots are located in the studied territory mainly in a regular manner, laid and surveyed according to the ICP-Forests methodology with some additions. The total area of the sample plots is a small part of the entire study area. One of the objectives of the study was to determine the possibility of using the k-NN (nearest neighbor method) to assess the state of forests throughout the whole studied territory by joint statistical processing of data from ground sample plots and Sentinel-2B imagery. The data of the ground-based sample plots were divided into 2 equal parts, one for the application of the k-NN method, the second for checking the results of the method application. The systematic error in determining the mean damage class of the tree stands on sample plots by the k-NN method turned out to be zero, the random error is equal to one point. These results offer a possibility to determine the state of the forest in the entire study area. The second objective of the study was to examine the possibility of using the short-wave vegetation index (SWVI) to assess the state of forests. As a result, a close statistically reliable dependence of the average score of the state of plantations and the value of the SWVI index was established, which makes it possible to use the established relationship to determine the state of forests throughout the studied territory. The joint use and statistical processing of remotely sensed data and ground-based test areas by the two studied methods make it possible to assess the state of forests throughout the large studied area within the image. The results obtained can be used to monitor the state of forests in large areas and design appropriate forestry protective measures.

关键词： Remote Sensing Sentinel-2B Imagery ICP-Forest Sample Plot Tree Stand Damage Class k-NN (Nearest Neighbor Method) Vegetation Index SWVI Nonlinear Regression Systematic error random error