scholarly journals COASTAL APPLICATIONS OF THE ERTS-A SATELLITE

1972 ◽  
Vol 1 (13) ◽  
pp. 113
Author(s):  
Orville T. Magoon ◽  
Douglas M. Pirie ◽  
John W. Jarman
Keyword(s):  
Multispectral Images ◽  
Precise Location ◽  
Multispectral Data ◽  
Topographic Features ◽  
Efficient Management ◽  
The Earth ◽  
Maximum Utility ◽  
Data Output ◽  
Constant Observation ◽  
One Year

This paper describes the Earth Resources Technology Satellite (ERTS) placed in orbit in July 1972 and the ERTS simulation high altitude aircraft flights which have been flown for approximately one year. The ERTS satellite and simulation programs conducted by the National Aeronautics and Space Administration (NASA) have been developed to demonstrate the techniques for efficient management of the earth's resources. To achieve this objective the ERTS-A satellite provides for the repetitive acquisition of high resolution multispectral data of the earth's surface on a global basis. Two sensor systems have been selected for this purpose: a fourchannel multispectral scanner (MSS) subsystem for ERTS-A and a threecamera return beam vidicon (RBV) system. Systematic repeating earth coverage under nearly constant observation conditions is provided for maximum utility of the multispectral images collected by the ERTS satellite, which operates in a circular sun synchronous nearly polar orbit at an altitude of 494 nautical miles. It circles the earth every 103 minutes completing 14 orbits per day and views the entire earth in 18 days. The orbit has been selected so that the satellite ground trace repeats its earth coverage at the same local time every 18-day period within 20 nautical miles. A number of data output products are available from this satellite which include 70 mm products for precise location of topographic features, 9.5 inch positive or paper prints and also computer compatible tapes or punched cards. Also described are the results of the ERTS-A simulation flights flown at an altitude of 65,000 feet as related to coastal studies. Simulations of both the RBV and MSS in coastal areas are presented.

Preliminary monthly gravity field models from kinematic orbits of SWARM Satellites

2021 ◽  
Author(s):  
Xingfu Zhang ◽  
Qiujie Chen ◽  
Yunzhong Shen
Keyword(s):  
Gravity Field ◽  
Large Scale ◽  
Earth System ◽  
The Earth ◽  
Swarm Satellites ◽  
Variable Gravity ◽  
Data Gap ◽  
One Year ◽  
Gravity Recovery ◽  
Gravity Field Models

<p>      Although the Gravity Recovery and Climate Experiment (GRACE) and GRACE Follow-On (GRACE FO) satellite missions play an important role in monitoring global mass changes within the Earth system, there is a data gap of about one year spanning July 2017 to May 2018, which leads to discontinuous gravity observations for monitoring global mass changes. As an alternative mission, the SWARM satellites can provide gravity observations to close this data gap. In this paper, we are dedicated to developing alternative monthly time-variable gravity field solutions from SWARM data. Using kinematic orbits of SWARM from ITSG for the period January 2015 to September 2020, we have generated a preliminary time series of monthly gravity field models named Tongji-Swarm2019 up to degree and order 60. The comparisons between Tongji-Swarm2019 and GRACE/GRACE-FO monthly solutions show that Tongji-Swarm2019 solutions agree with GRACE/GRACE-FO models in terms of large-scale mass change signals over amazon, Greenland and other regions. We can conclude that Tongji-Swarm2019 monthly gravity field models are able to close the gap between GRACE and GRACE FO.</p>

Theories of Polar Motion from Tisserand to Poincaré (1890 – 1910)

2000 ◽  
Vol 178 ◽  
pp. 41-66 ◽  
Author(s):  
P. Melchior
Keyword(s):  
Polar Motion ◽  
Scientific Community ◽  
Circular Motion ◽  
Computing Power ◽  
The Earth ◽  
Fixed Pole ◽  
One Year ◽  
Elliptical Motion ◽  
The Impact ◽  
Chandler Period

AbstractThe discovery by Seth C. Chandler (1891) that the motion of the pole (the reality of which had been established by K.F. Küstner and by the simultaneous latitude observations at Honolulu and Berlin by German astronomers) resulted from two components i.e. a free circular motion with a period of 427 days and a forced elliptical motion with a period of 365.25 days, raised considerable interest in the scientific community of astronomers and geophysicists.The celebrated Mécanique Céleste of Tisserand (1890) had been published just one year before at a time when doubts still persisted and arguments could be presented in favor of the fixed pole. Starting with Tisserand’s arguments, we describe in this paper the impact of the successive contributions by A. Greenhill, S. Newcomb, Th. Sloudsky, S. Hough, G. Herglotz, A. Love, J. Larmor and H. Poincaré to the solution of the problems raised by the Chandler period.The lines of reasoning taken by these eminent scientists were rigorously correct so that, after about one hundred years, contemporary researchers, who benefit from a far better knowledge of the inner structure of the Earth and are able to take advantage of modern computing power, do not contradict any of their conclusions and instead refine them with an accuracy which was not imaginable one century ago.

scholarly journals VLBI studies of the nutations of the earth

1988 ◽  
Vol 129 ◽  
pp. 371-375
Author(s):  
T. A. Herring
Keyword(s):  
Truncation Error ◽  
Very Long Baseline Interferometry ◽  
Long Baseline ◽  
The Earth ◽  
Vlbi Data ◽  
One Year ◽  
Nutation Series ◽  
Theoretical Considerations ◽  
Active Investigation

The application of very–long–baseline interferometry (VLBI) to the study of the nutations of the earth has yielded unprecedented accuracy for the experimental determination of the coefficients of the nutation series. The analysis of six years of VLBI data has yielded corrections to the coefficients of the seven largest terms in the IAU 1980 nutation series with periods of one year or less, with accuracies approaching the truncation error of this nutation series (0.1 mas). The nutation series coefficients computed from the VLBI data, and those obtained from theoretical considerations (the IAU 1980 nutation series), are in excellent agreement. The largest corrections are to the coefficients of the retrograde annual nutation [2.0 ± 0.1 mas], the prograde semiannual nutation [(0.5 - ι 0.4) ±0.1 mas], and the prograde 13.7 day nutation [−0.4 ± 0.1 mas]. (The imaginary term for the semiannual nutation represents a term 90° out–of–phase with the arguments of the nutation series.) The geophysical implications of these results are currently under active investigation. We discuss the methods used to extract the nutation information from the VLBI data, the calculations of the uncertainties of the resultant corrections to the coefficients of the nutation series, and the current research into the nutations of the earth.

scholarly journals New Determination of the “Decade” Fluctuations in the Rotation of the Earth 1860–1978

1979 ◽  
Vol 82 ◽  
pp. 55-57
Author(s):  
L. V. Morrison
Keyword(s):  
Angular Momentum ◽  
Electromagnetic Coupling ◽  
Viscous Stress ◽  
Mantle Boundary ◽  
Core Mantle Boundary ◽  
Topographic Features ◽  
The Core ◽  
The Earth ◽  
Rotation Of The Earth

Observations of the Earth's rotation have shown irregular variations of rate which have characteristic times of decades. These have been attributed to transfer of angular momentum between core and mantle by some mechanism such as inertial coupling, viscous stress, electromagnetic coupling or stresses produced by topographic features on the core mantle boundary.

Extreme TGF Imaging by ASIM

2020 ◽  
Author(s):  
Víctor Reglero ◽  
Paul Connell ◽  
Javier Navarro ◽  
Christopher Eyles ◽  
Nikolai Ostgaard ◽  
...  
Keyword(s):  
Convective Cell ◽  
Imaging Data ◽  
Source Imaging ◽  
Extended Source ◽  
The Earth ◽  
Operational Phase ◽  
One Year ◽  
Asymmetric Matter ◽  
Imaging Conditions ◽  
Accurate Imaging

<p>One year after the starting of ASIM operational phase, we have succeeded to perform accurate Imaging of 54 TGF.  Among them, some have been analysed at extreme imaging conditions in terms of TGF position at the MXGS partially coded field of view.  20 TGF events have angular distances larger than 40º respect to the MXGS FOV centre. Extreme cases at angular distances larger than 50º are presented. Validation of TGF position by WLN data is included in the discussion.</p><p>The canonical value of 32 LED cnts as the minimum fluency for TGF imaging defined during MXGS development was checked using low luminosity TGF.  At the present, we have succeeded to obtain imaging solution for 7 TGF with less than 20 cnts. A sample is presented with indication of position accuracy and S/N ratios.  </p><p>Last part of the presentation is the discussion of a TGF with a very large and asymmetric probability distribution at the MXGS FOV that suggest the TGF as an extended source. Imaging data projected to the Earth surface is compared with GOES data, showing that the TGF is at the edge of a large convective cell, close to the TGF imaging data map.  Therefore, we can conclude that for some bright TGF it is possible to estimate the TGF fireball dimensions generated by the iteration of TGF photons with local atmospheric asymmetric matter distributions. The presence of a large CZT tail is coherent with the size of the convective cell.</p>

scholarly journals FPGA Implementation of Multispectral Image Compression for Satellite Images

2019 ◽  
Vol 8 (9) ◽  
pp. 561-567
Keyword(s):  
Image Compression ◽  
Satellite Images ◽  
Earth Satellite ◽  
Vital Role ◽  
Fpga Implementation ◽  
Multispectral Image ◽  
Complex Wavelet Transform ◽  
Multispectral Data ◽  
The Earth ◽  
Multispectral Image Compression

Multispectral image compression plays a vital role in remote sensing through satellites. Satellite images are more powerful approach to study the space information and research the geographical nature of the earth. Satellite images contains the huge amount of data and it requires more bandwidth for transmission and more memory for storage. Multispectral image compression reduces the size of the multispectral data and makes it easy for storage and transmission to the earth station form the satellite. The image is compressed by reducing the irrelevant and redundant part of data. This paper presents FPGA implementation of multispectral image compression using Dual Tree Complex Wavelet Transform (DTCWT) and Arithmetic Coding. This compression algorithm is implemented and simulated using MATLAB and XILINX ISE14.5 simulator. The FPGA Spartan -6 architecture is used to implement the algorithm. The proposed method gives better result in PSNR and MSE ratio as compared to DWT.

scholarly journals ENHANCED CLASSIFICATION MODEL FOR MULTISPECTRAL OBSERVATIONS FROM THE EARTH

2018 ◽  
Vol IV-4 ◽  
pp. 221-226
Author(s):  
I. E. Villalon-Turrubiates ◽  
M. J. Llovera-Torres
Keyword(s):  
Remote Sensing ◽  
Decision Model ◽  
Accurate Result ◽  
Classification Model ◽  
Multispectral Images ◽  
Performance Study ◽  
Spectral Bands ◽  
The Earth ◽  
Multispectral Remote Sensing ◽  
Decision Making Rule

<p><strong>Abstract.</strong> The image classification procedure to identify remote sensing signatures from a particular geographical region can be performed with an identification model that has the ability to use large datasets to reach an accurate result. This novel methodology is referred to as the Statistical Enhanced Classification algorithm, which has been developed to employ multispectral images based in the statistical supervised learning theory and can be used for applications in environmental monitoring and analysis. This paper presents the performance study of the proposed methodology using both, multispectral synthetic images and multispectral remote sensing images. The obtained results are accurate due to the use of several spectral bands, the use of statistics such as mean and standard deviation for the training classes and for the pixel neighborhood, which provides more robust information, and the decision-making rule that has the ability to decide if the pixel is not belonging to a predefined class, which leads to an accurate decision model.</p>

scholarly journals Analysis of the Influence of Vegetation Index Choice on the Classification of Satellite Images for Monitoring Forest Pathology

2020 ◽  
pp. paper49-1-paper49-12
Author(s):  
Evgeniy Trubakov ◽  
Olga Trubakova
Keyword(s):  
Satellite Images ◽  
Vegetation Index ◽  
Vegetation Indices ◽  
Multispectral Images ◽  
Classification Methods ◽  
Planted Forests ◽  
The Earth ◽  
Evaluation Algorithm ◽  
And Control

Rational use of natural resources and control over their recovery, as well as over destruction due to natural and technogenic causes, is currently one of the most urgent problems of the humanity. Forests are no exception. Multispectral images from Earth’s satellites are most often used for monitoring changes in forest planting. This is due to the fact that merging images taken in certain spectra makes it possible to recognize vegetation containing chlorophyll quite well. It also allows to detect changes in the level of chlorophyll, which shows the differences between healthy and damaged plants. Large areas of planted forests create the need to process huge amounts of data, which is difficult to do manually. One of the most important stages of image processing is the classification of objects in these images. This paper deals with various classification methods used to solve the problem of classifying images of remote sensing of the Earth. As a result, it was decided to evaluate the accuracy of classification methods on various vegetation indices. In the course of the study, the evaluation algorithm was determined, as well as one of the options for analyzing the results obtained. Conclusions were made about the work of classification methods on different vegetation indices.

Indigenous Qualitative Inquiry

2012 ◽  
Vol 5 (1) ◽  
pp. 51-72 ◽  
Author(s):  
Marcelo Diversi ◽  
Dan Henhawk
Keyword(s):  
Indigenous Peoples ◽  
Knowledge Production ◽  
Ethical Issues ◽  
Ways Of Knowing ◽  
Qualitative Inquiry ◽  
The Earth ◽  
First Arrival ◽  
One Year ◽  
Interpretive Communities

Five centuries after the first arrival of European settlers in what they called the Americas, indigenous peoples and ways of knowing continue to be largely represented and reified by Western scholars and epistemologies. We argue here that, even within Qualitative Inquiry and its critical paradigms and theories, indigenous bodies and narratives continue to be relatively scarce as our interpretive communities attempt to advance decolonizing knowledge production, pedagogy, and praxis. In this article, we argue that this persistent segregation is related to an academic structure that continues to privilege Western paradigms (e.g., theoretical sophistication over visceral knowledge of oppression) and ways of knowing (e.g., reductionist binary definitions of indigeneity still too obsessed with authenticity). The center-piece of our article and critique is an email exchange between the authors about ontological, epistemological, and ethical issues of indigenous qualitative inquiry over the period of one year. We attempt to use our exchange as an instantiation—a textual, intellectual, and emotional performance—of ontological questions on indigenous qualitative inquiry: Who is indigenous? Are there common grounds among indigenous peoples of the earth? And if so, can we find more effective ways to gather in these common grounds in the 21st century? We conclude by offering our own suggestions toward decolonizing imaginations and praxis.

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