Rotational Variability of Earth's Polar Regions: Implications for Detecting Snowball Planets

NASA Astrophysics Data System (ADS)

Cowan, Nicolas B.; Robinson, Tyler; Livengood, Timothy A.; Deming, Drake; Agol, Eric; A'Hearn, Michael F.; Charbonneau, David; Lisse, Carey M.; Meadows, Victoria S.; Seager, Sara; Shields, Aomawa L.; Wellnitz, Dennis D.

2011-04-01

We have obtained the first time-resolved, disk-integrated observations of Earth's poles with the Deep Impact spacecraft as part of the EPOXI mission of opportunity. These data mimic what we will see when we point next-generation space telescopes at nearby exoplanets. We use principal component analysis (PCA) and rotational light curve inversion to characterize color inhomogeneities and map their spatial distribution from these unusual vantage points, as a complement to the equatorial views presented by Cowan et al. in 2009. We also perform the same PCA on a suite of simulated rotational multi-band light curves from NASA's Virtual Planetary Laboratory three-dimensional spectral Earth model. This numerical experiment allows us to understand what sorts of surface features PCA can robustly identify. We find that the EPOXI polar observations have similar broadband colors as the equatorial Earth, but with 20%-30% greater apparent albedo. This is because the polar observations are most sensitive to mid-latitudes, which tend to be more cloudy than the equatorial latitudes emphasized by the original EPOXI Earth observations. The cloudiness of the mid-latitudes also manifests itself in the form of increased variability at short wavelengths in the polar observations and as a dominant gray eigencolor in the south polar observation. We construct a simple reflectance model for a snowball Earth. By construction, our model has a higher Bond albedo than the modern Earth; its surface albedo is so high that Rayleigh scattering does not noticeably affect its spectrum. The rotational color variations occur at short wavelengths due to the large contrast between glacier ice and bare land in those wavebands. Thus, we find that both the broadband colors and diurnal color variations of such a planet would be easily distinguishable from the modern-day Earth, regardless of viewing angle.

Earth Rotation Parameters from DSN VLBI: 1994

NASA Technical Reports Server (NTRS)

Steppe, J. A.; Oliveau, S. H.; Sovers, O. J.

1994-01-01

In this report, Earth Rotation Parameter (ERP) estimates ahve been obtained from an analysis of Deep Space Network (DSN) VLBI data that directly aligns its celestial and terrestrial reference frames with those of the International Earth Rotation Service (IERS).

Earth Rotation Dynamics: Review and Prospects

NASA Technical Reports Server (NTRS)

Chao, Benjamin F.

2004-01-01

Modem space geodetic measurement of Earth rotation variations, particularly by means of the VLBI technique, has over the years allowed studies of Earth rotation dynamics to advance in ever-increasing precision, accuracy, and temporal resolution. A review will be presented on our understanding of the geophysical and climatic causes, or "excitations", for length-of-day change, polar motion, and nutations. These excitations sources come from mass transports that constantly take place in the Earth system comprised of the atmosphere, hydrosphere, cryosphere, lithosphere, mantle, and the cores. In this sense, together with other space geodetic measurements of time-variable gravity and geocenter motion, Earth rotation variations become a remote-sensing tool for the integral of all mass transports, providing valuable information about the latter on a wide range of spatial and temporal scales. Future prospects with respect to geophysical studies with even higher accuracy and resolution will be discussed.

Mountain building and earth rotation.

NASA Astrophysics Data System (ADS)

Vermeersen, L. L. A.; Sabadini, R.; Spada, G.; Vlaar, N. J.

1994-06-01

Whereas the present-day true polar wander and the secular non-tidal acceleration of the Earth have usually been attributed to postglacial rebound, it has recently been suggested that non-glacially induced vertical tectonic movements taking place under non-isostatic conditions can also be effective in changing the Earth's rotation. The authors present a case study in which they analyse the effects of some simple uplift histories of the Himalayas and the Tibetan Plateau on the rotational axis and on the second-degree zonal harmonic of the geoid, for time-scales of up to a few million years.

Progress in Research on Diurnal and Semidiurnal Earth Rotation Change

NASA Astrophysics Data System (ADS)

Xu, Xueqing

2015-08-01

We mainly focus on the progress of research on high frequency changes in the earth rotation. Firstly, we review the development course and main motivating factors of the diurnal and semidiurnal earth rotation change. In recent decades, earth orientation has been monitored with increasing accuracy by advanced space-geodetic techniques, including lunar and satellite laser ranging, very long baseline interferometry and the global positioning system. We are able to obtain the Earth Rotation Parameters (ERP, polar motion and rotation rate changes) by even 1 to 2 hours observation data, form which obvious diurnal and semidiurnal signals can be detected, and compare them with the predicted results by the ocean model. Both the amplitude and phase are in good agreement in the main diurnal and semidiurnal wave frequency, especially for the UT1, whose compliance is 90%, and 60% for polar motion, there are 30% motivating factor of the diurnal and semidiurnal polar motion have not been identified. Then we comprehensively review the different types of global ocean tidal correction models since the last eighties century, as well as the application research on diurnal and semidiurnal polar motion and UT1, the current ocean tidal correction models have 10% to 20% uncertainty, and need for further refinement.

Earth Rotational Variations Excited by Geophysical Fluids

NASA Technical Reports Server (NTRS)

Chao, Benjamin F.

2004-01-01

Modern space geodetic measurement of Earth rotation variations, particularly by means of the VLBI technique, has over the years allowed studies of Earth rotation dynamics to advance in ever-increasing precision, accuracy, and temporal resolution. A review will be presented on our understanding of the geophysical and climatic causes, or "excitations". for length-of-day change, polar motion, and nutations. These excitations sources come from mass transports that constantly take place in the Earth system comprised of the atmosphere, hydrosphere, cryosphere, lithosphere, mantle, and the cores. In this sense, together with other space geodetic measurements of time-variable gravity and geocenter motion, Earth rotation variations become a remote-sensing tool for the integral of all mass transports, providing valuable information about the latter on a wide range of spatial and temporal scales. Future prospects with respect to geophysical studies with even higher accuracy and resolution will be discussed.

Design of experiment for earth rotation and baseline parameter determination from very long baseline interferometry

NASA Technical Reports Server (NTRS)

Dermanis, A.

1977-01-01

The possibility of recovering earth rotation and network geometry (baseline) parameters are emphasized. The numerical simulated experiments performed are set up in an environment where station coordinates vary with respect to inertial space according to a simulated earth rotation model similar to the actual but unknown rotation of the earth. The basic technique of VLBI and its mathematical model are presented. The parametrization of earth rotation chosen is described and the resulting model is linearized. A simple analysis of the geometry of the observations leads to some useful hints on achieving maximum sensitivity of the observations with respect to the parameters considered. The basic philosophy for the simulation of data and their analysis through standard least squares adjustment techniques is presented. A number of characteristic network designs based on present and candidate station locations are chosen. The results of the simulations for each design are presented together with a summary of the conclusions.

Nonuniformity of the Earth's rotation and the motion of the poles

NASA Technical Reports Server (NTRS)

Sidorenkov, N. S.

1983-01-01

The study of the nonuniformity of the Earth's rotation and the motion of the poles has great practical and theoretical significance. This study makes it possible to determine the coordinates of celestial and terrestrial objects, and to gain information in many domains of earth science. This paper reviews studies of rotation nonuniformity and polar motion, giving attention to astronomical data; the nature of periodic oscillations of the Earth's rotation; the nature of long-period variations of the Earth's rotation rate; and the use of Earth-rotation data in hydrometeorology.

Progress in geophysical aspects of the rotation of the earth

NASA Technical Reports Server (NTRS)

Lambeck, K.

1978-01-01

The geophysical causes and consequences of the Earth's rotation are reviewed. Specific topics covered include: (1) the motion of the rotation axis in space, precession and nutation; (2) the motion of the rotation axis relative to the Earth, polar motion; and (3) the rate of rotation about this axis, or changes in the length of day. Secular decrease in obliquity and evolution of the Earth-Moon system are also discussed.

Observed tidal braking in the earth/moon/sun system

NASA Technical Reports Server (NTRS)

Christodoulidis, D. C.; Smith, D. E.; Williamson, R. G.; Klosko, S. M.

1987-01-01

The low degree and order terms in the spherical harmonic model of the tidal potential were observed through the perturbations which are induced on near-earth satellite orbital motions. Evaluations of tracking observations from 17 satellites and a GEM-T1 geopotential model were used in the tidal recovery which was made in the presence of over 600 long-wavelength coefficients from 32 major and minor tides. Wahr's earth tidal model was used as a basis for the recovery of the ocean tidal terms. Using this tidal model, the secular change in the moon's mean motion due to tidal dissipation was found to be -25.27 + or - 0.61 arcsec/century squared. The estimation of lunar acceleration agreed with that observed from lunar laser ranging techniques (-24.9 + or - 1.0 arcsec/century squared), with the corresponding tidal braking of earth's rotation being -5.98 + or - 0.22 x 10 to the minus 22 rad/second squared. If the nontidal braking of the earth due to the observed secular change in the earth's second zonal harmonic is considered, satellite techniques yield a total value of the secular change of the earth's rotation rate of -4.69 + or - 0.36 x 10 to the minus 22 rad/second squared.

Observed tidal braking in the earth/moon/sun system

NASA Technical Reports Server (NTRS)

Christodoulidis, D. C.; Smith, D. E.; Williamson, R. G.; Klosko, S. M.

1988-01-01

The low degree and order terms in the spherical harmonic model of the tidal potential were observed through the perturbations which are induced on near-earth satellite orbital motions. Evaluations of tracking observations from 17 satellites and a GEM-T1 geopotential model were used in the tidal recovery which was made in the presence of over 600 long-wavelength coefficients from 32 major and minor tides. Wahr's earth tidal model was used as a basis for the recovery of the ocean tidal terms. Using this tidal model, the secular change in the moon's mean motion due to tidal dissipation was found to be -25.27 + or - 0.61 arcsec/century-squared. The estimation of lunar acceleration agreed with that observed from lunar laser ranging techniques (-24.9 + or - 1.0 arcsec/century-squared), with the corresponding tidal braking of earth's rotation being -5.98 + or - 0.22 X 10 to the -22 rad/second-squared. If the nontidal braking of the earth due to the observed secular change in the earth's second zonal harmonic is considered, satellite techniques yield a total value of the secular change in the earth's rotation rate of -4.69 + or - 0.36 X 10 to the -22 rad/second-squared.

Construction of the Non-Rigid Earth Rotation Series

NASA Astrophysics Data System (ADS)

Pashkevich, V. V.

2007-01-01

Last years a lot of attempts to derive a high-precision theory of the non-rigid Earth rotation are carried out. For these purposes different transfer functions are used. Usually these transfer functions are applied to the series representing the nutation in the longitude and the obliquity of the rigid Earth rotation with respect to the ecliptic of date. The aim of this investigation is a construction of new high-precision non-rigid Earth rotation series (SN9000), dynamically adequate to the DE404/LE404 ephemeris over 2000 time span years, which are presented as functions of the Euler angles Ψ, θ and φ with respect to the fixed ecliptic plane and equinox J2000.0.

Variations in the rotation of the earth

NASA Astrophysics Data System (ADS)

Carter, W. E.; Robertson, D. S.; Pettey, J. E.; Tapley, B. D.; Schutz, B. E.; Eanes, R. J.; Miao, L.

Variations in the earth's rotation (UTI) and length of day have been tracked at the submillisecond level by astronomical radio interferometry and laser ranging to the LAGEOS satellite. Three years of regular measurements reveal complex patterns of variations including UTI fluctuations as large as 5 milliseconds in a few weeks. Comparison of the observed changes in length of day with variations in the global atmospheric angular momentum indicates that the dominant cause of changes in the earth's spin rate, on time scales from a week to several years, is the exchange of angular momentum between the atmosphere and the mantle. The unusually intense El Nino of 1982-1983 was marked by a strong peak in the length of day.

Complex demodulation in VLBI estimation of high frequency Earth rotation components

NASA Astrophysics Data System (ADS)

Böhm, S.; Brzeziński, A.; Schuh, H.

2012-12-01

The spectrum of high frequency Earth rotation variations contains strong harmonic signal components mainly excited by ocean tides along with much weaker non-harmonic fluctuations driven by irregular processes like the diurnal thermal tides in the atmosphere and oceans. In order to properly investigate non-harmonic phenomena a representation in time domain is inevitable. We present a method, operating in time domain, which is easily applicable within Earth rotation estimation from Very Long Baseline Interferometry (VLBI). It enables the determination of diurnal and subdiurnal variations, and is still effective with merely diurnal parameter sampling. The features of complex demodulation are used in an extended parameterization of polar motion and universal time which was implemented into a dedicated version of the Vienna VLBI Software VieVS. The functionality of the approach was evaluated by comparing amplitudes and phases of harmonic variations at tidal periods (diurnal/semidiurnal), derived from demodulated Earth rotation parameters (ERP), estimated from hourly resolved VLBI ERP time series and taken from a recently published VLBI ERP model to the terms of the conventional model for ocean tidal effects in Earth rotation recommended by the International Earth Rotation and Reference System Service (IERS). The three sets of tidal terms derived from VLBI observations extensively agree among each other within the three-sigma level of the demodulation approach, which is below 6 μas for polar motion and universal time. They also coincide in terms of differences to the IERS model, where significant deviations primarily for several major tidal terms are apparent. An additional spectral analysis of the as well estimated demodulated ERP series of the ter- and quarterdiurnal frequency bands did not reveal any significant signal structure. The complex demodulation applied in VLBI parameter estimation could be demonstrated a suitable procedure for the reliable reproduction of

Rotationally driven 'zebra stripes' in Earth's inner radiation belt.

PubMed

Ukhorskiy, A Y; Sitnov, M I; Mitchell, D G; Takahashi, K; Lanzerotti, L J; Mauk, B H

2014-03-20

Structured features on top of nominally smooth distributions of radiation-belt particles at Earth have been previously associated with particle acceleration and transport mechanisms powered exclusively by enhanced solar-wind activity. Although planetary rotation is considered to be important for particle acceleration at Jupiter and Saturn, the electric field produced in the inner magnetosphere by Earth's rotation can change the velocity of trapped particles by only about 1-2 kilometres per second, so rotation has been thought inconsequential for radiation-belt electrons with velocities of about 100,000 kilometres per second. Here we report that the distributions of energetic electrons across the entire spatial extent of Earth's inner radiation belt are organized in regular, highly structured and unexpected 'zebra stripes', even when the solar-wind activity is low. Modelling reveals that the patterns are produced by Earth's rotation. Radiation-belt electrons are trapped in Earth's dipole-like magnetic field, where they undergo slow longitudinal drift motion around the planet because of the gradient and curvature of the magnetic field. Earth's rotation induces global diurnal variations of magnetic and electric fields that resonantly interact with electrons whose drift period is close to 24 hours, modifying electron fluxes over a broad energy range into regular patterns composed of multiple stripes extending over the entire span of the inner radiation belt.

Earth rotation, station coordinates and orbit determination from satellite laser ranging

NASA Astrophysics Data System (ADS)

Murata, Masaaki

The Project MERIT, a special program of international colaboration to Monitor Earth Rotation and Intercompare the Techniques of observation and analysis, has come to an end with great success. Its major objective was to evaluate the ultimate potential of space techniques such as VLBI and satellite laser ranging, in contrast with the other conventional techniques, in the determination of rotational dynamics of the earth. The National Aerospace Laboratory (NAL) has officially participated in the project as an associate analysis center for satellite laser technique for the period of the MERIT Main Campaign (September 1983-October 1984). In this paper, the NAL analysis center results are presented.

Dynamic ocean-tide effects on Earth's rotation

NASA Technical Reports Server (NTRS)

Dickman, S. R.

1993-01-01

This article develops 'broad-band' Liouville equations which are capable of determining the effects on the rotation of the Earth of a periodic excitation even at frequencies as high as semi-diurnal; these equations are then used to predict the rotational effects of altimetric, numerical and 32-constituent spherical harmonic ocean-tide models. The rotational model includes a frequency-dependent decoupled core, the effects of which are especially marked near retrograde diurnal frequencies; and a fully dynamic oceanic response, whose effects appear to be minor despite significant frequency dependence. The model also includes solid-earth effects which are frequency dependent as the result of both anelasticity at long periods and the fluid-core resonance at nearly diurnal periods. The effects of both tidal inertia and relative angular momentum on Earth rotation (polar motion, length of day, 'nutation' and Universal Time) are presented for 32 long- and short-period ocean tides determined as solutions to the author's spherical harmonic tide theory. The lengthening of the Chandler wobble period by the pole tide is also re-computed using the author's full theory. Additionally, using the spherical harmonic theory, tidal currents and their effects on rotation are determined for available numerical and altimetric tide height models. For all models, we find that the effects of tidal currents are at least as important as those of tide height for diurnal and semi-diurnal constituents.

Earth's rotation variations and earthquakes 2010-2011

NASA Astrophysics Data System (ADS)

Ostřihanský, L.

2012-01-01

In contrast to unsuccessful searching (lasting over 150 years) for correlation of earthquakes with biweekly tides, the author found correlation of earthquakes with sidereal 13.66 days Earth's rotation variations expressed as length of a day (LOD) measured daily by International Earth's Rotation Service. After short mention about earthquakes M 8.8 Denali Fault Alaska 3 November 2002 triggered on LOD maximum and M 9.1 Great Sumatra earthquake 26 December 2004 triggered on LOD minimum and the full Moon, the main object of this paper are earthquakes of period 2010-June 2011: M 7.0 Haiti (12 January 2010 on LOD minimum, M 8.8 Maule Chile 12 February 2010 on LOD maximum, map constructed on the Indian plate revealing 6 earthquakes from 7 on LOD minimum in Sumatra and Andaman Sea region, M 7.1 New Zealand Christchurch 9 September 2010 on LOD minimum and M 6.3 Christchurch 21 February 2011 on LOD maximum, and M 9.1 Japan near coast of Honshu 11 March 2011 on LOD minimum. It was found that LOD minimums coincide with full or new Moon only twice in a year in solstices. To prove that determined coincidences of earthquakes and LOD extremes stated above are not accidental events, histograms were constructed of earthquake occurrences and their position on LOD graph deeply in the past, in some cases from the time the IERS (International Earth's Rotation Service) started to measure the Earth's rotation variations in 1962. Evaluations of histograms and the Schuster's test have proven that majority of earthquakes are triggered in both Earth's rotation deceleration and acceleration. Because during these coincidences evident movements of lithosphere occur, among others measured by GPS, it is concluded that Earth's rotation variations effectively contribute to the lithospheric plates movement. Retrospective overview of past earthquakes revealed that the Great Sumatra earthquake 26 December 2004 had its equivalent in the shape of LOD graph, full Moon position, and character of aftershocks

Does The Sun Rotate Around The Earth Or Does The Earth Rotate Around the Sun? An Important Key to Evaluating Science Education

NASA Astrophysics Data System (ADS)

Isobe, S.

2006-08-01

The Japan Spaceguard Association, Tokyo, Japan Sciences are continuously developing. This is a good situation for the sciences, but when one tries to teach scientific results, it is hard to decide which levels of science should be taught in schools. The point to evaluate is not only the quality of scientific accuracy, but also the method with which school students of different scientific abilities study scientific results. In astronomy, an important question, which is "Does the Sun rotate around the Earth or does the Earth rotate around the Sun?" can be used to evaluate student abilities. Scientifically, it is obvious that the latter choice is the better answer, but it is not so obvious for the lower-grade students and also for the lower-ability students even in the higher grades. If one sees daily the sky without scientific knowledge, one has an impression of "the Sun rotates around the Earth," and for his rest of his life he will not see any problem. If one wants to be a scientist, though, he should know that "the Earth rotates around the Sun" before reaching university level. If he will become a physical scientist, he should understand that it is not correct to say "the Earth rotates around the Sun," but he should know that the Earth rotates around the center of gravity of the solar system. A similar type of question is "has the Earth the shape of a sphere, or a pear, or a geoid?" There are many teachers with varying ranges of students who do not understand the proper level of science instruction. When students of lower capacity are instructed to understand concepts with the higher degrees of sophistication, they can easily lose their interest in the sciences. This happens in many countries, especially in Japan, where there are many different types of people with different jobs. We, as educators, should appreciate that the students can be interested in any given scientific idea, no matter what level of sophistication it is.

On Physical Interpretation of the In-Site Measurement of Earth Rotation by Ring Laser Gyrometers

NASA Technical Reports Server (NTRS)

Chao, B. F.

2004-01-01

Large ring laser gyrometers under development have demonstrated the capability of detecting minute ground motions and deformations on a wide range of timescales. The next challenge and goal is to measure the Earth's rotation variations to a precision that rivals that of the present space-geodesy techniques, thus providing an in-situ (and cost effective alternatives of Earth rotation measurement for geophysical research and geodetic applications. Aside from thermal and mechanical instabilities, "undesirable" ground motion and tilt that appear in the signal will need to be removed before any variation in Earth rotation can be detected. Removal of these signals, some of them are larger than the sought rotation signals, has been a typical procedure in many precise geophysical instruments, such as gravimeters, seismometers, and tiltmeters. The remaining Earth rotation signal resides in both the spin around the axis and in the orientation of the axis. In the case of the latter, the in-situ measurement is complementary to the space-geodetic observables in terms of polar motion and nutation, a fact to be exploited.

MaRGEE: Move and Rotate Google Earth Elements

NASA Astrophysics Data System (ADS)

Dordevic, Mladen M.; Whitmeyer, Steven J.

2015-12-01

Google Earth is recognized as a highly effective visualization tool for geospatial information. However, there remain serious limitations that have hindered its acceptance as a tool for research and education in the geosciences. One significant limitation is the inability to translate or rotate geometrical elements on the Google Earth virtual globe. Here we present a new JavaScript web application to "Move and Rotate Google Earth Elements" (MaRGEE). MaRGEE includes tools to simplify, translate, and rotate elements, add intermediate steps to a transposition, and batch process multiple transpositions. The transposition algorithm uses spherical geometry calculations, such as the haversine formula, to accurately reposition groups of points, paths, and polygons on the Google Earth globe without distortion. Due to the imminent deprecation of the Google Earth API and browser plugin, MaRGEE uses a Google Maps interface to facilitate and illustrate the transpositions. However, the inherent spatial distortions that result from the Google Maps Web Mercator projection are not apparent once the transposed elements are saved as a KML file and opened in Google Earth. Potential applications of the MaRGEE toolkit include tectonic reconstructions, the movements of glaciers or thrust sheets, and time-based animations of other large- and small-scale geologic processes.

The earth's C21 and S21 gravity coefficients and the rotation of the core

NASA Technical Reports Server (NTRS)

Wahr, John M.

1987-01-01

Observational results for the earth's C21 and S21 gravity coefficients can be used to constrain the mean equatorial rotation of the core with respect to the mantle. Current satellite gravity solutions suggest the equatorial rotation rate is no larger than 1 x 10 to the -7th times the earth's diurnal spin rate, a limit more than one order of magnitude smaller than the polar rotation rate inferred from the westward drift of the earth's magnetic field. The next generation gravity solutions should improve this constraint by more than one order of magnitude. Implications for the fluid pressure at the core-mantle boundary and for the shape of that boundary are discussed.

Fortnightly Earth Rotation, Ocean Tides, and Mantle Anelasticity

NASA Technical Reports Server (NTRS)

Ray, Richard D.; Egbert, Gary D.

2011-01-01

Sustained accurate measurements of earth rotation are one of the prime goals of Global Geodetic Observing System (GGOS). We here concentrate on the fortnightly (Mf) tidal component of earth-rotation data to obtain new results concerning anelasticity of the mantle at this period. The study comprises three parts: (1) a new determination of the Mf component of polar motion and length-of-day from a multi-decade time series of space-geodetic data; (2) the use of the polar-motion determination as one constraint in the development of a hydrodynamic ocean model of the Mf tide; and (3) the use of these results to place new constraints on mantle anelasticity. Our model of the Mf ocean tide assimilates more than fourteen years of altimeter data from the Topex/Poseidon and Jason-1 satellites. The polar motion data, plus tide-gauge data and independent altimeter data, give useful additional information, with only the polar motion putting constraints on tidal current velocities. The resulting ocean-tide model, plus the dominant elastic body tide, leaves a small residual in observed length-of-day caused by mantle anelasticity. The inferred effective tidal 0 of the anelastic body tide is 90 and is in line with a omega-alpha frequency dependence with alpha in the range 0.2--0.3.

On possible interconnections between Climate Change and Earth rotation

NASA Astrophysics Data System (ADS)

Zotov, Leonid; Christian, Bizouard; Sidorenkov, Nikolay

The question of interconnections between rotation of the Earth and Climate Change raised more, then 30 years ago. In Lambeck’s, Sidorenkov’s and others books the correlation between the secular changes of temperature and rotation velocity of the Earth was found. Since Climate Change brings to the redistribution of water and ice mass, ocean currents and atmospheric circulation, it also influences the angular momentum and moment of inertia of the Earth system, what causes variations in its rotation. We present the results of analysis of global temperature, sea level, Chandler wobble, atmospheric winds, and length of day (LOD) changes with arguments testifying possible interrelations between these processes and their dependence on space factors.

JEOS. The JANUS earth observation satellite

NASA Astrophysics Data System (ADS)

Molette, P.; Jouan, J.

The JANUS multimission platform has been designed to minimize the cost of the satellite (by a maximum reuse of equipment from other proprogrammes) and of its associated launch by Aŕiane (by a piggy-back configuration optimized for Ariane 4). The paper describes the application of the JANUS platform to an Earth observation mission with the objective to provide a given country with a permanent monitoring of its earth resources by exploitation of spaceborne imagery. According to this objective, and to minimize the overall system and operational cost, the JANUS Earth Observation Satellite (JEOS) will provide a limited coverage with real time transmission of image data, thus avoiding need for on-board storage and simplifying operations. The JEOS operates on a low earth, near polar sun synchronous orbit. Launched in a piggy-back configuration on Ariane 4, with a SPOT or ERS spacecraft, it reaches its operational orbit after a drift orbit of a few weeks maximum. In its operational mode, the JEOS is 3-axis stabilised, earth pointed. After presentation of the platform, the paper describes the solid state push-broom camera which is composed of four optical lenses mounted on a highly stable optical bench. Each lens includes an optics system, reused from an on-going development, and two CCD linear arrays of detectors. The camera provides four registered channels in visible and near IR bands. The whole optical bench is supported by a rotating mechanism which allows rotation of the optical axis in the across-track direction. The JEOS typical performance for a 700 km altitude is then summarized: spatial resolution 30 m, swath width 120 km, off-track capability 325 km,… The payload data handling and transmission electronics, derived from the French SPOT satellite, realizes the processing, formatting, and transmission to the ground; this allows reuse of the standard SPOT receiving stations. The camera is only operated when the spacecraft is within the visibility of the ground

The Coupling between Earth's Inertial and Rotational Eigenmodes

NASA Astrophysics Data System (ADS)

Triana, S. A.; Rekier, J.; Trinh, A.; Laguerre, R.; Zhu, P.; Dehant, V. M. A.

2017-12-01

Wave motions in the Earth's fluid core, supported by the restoring action of both buoyancy (within the stably stratified top layer) and the Coriolis force, lead to the existence of global oscillation modes, the so-called gravito-inertial modes. These fluid modes can couple with the rotational modes of the Earth by exerting torques on the mantle and the inner core. Viscous shear stresses at the fluid boundaries, along with pressure and gravitation, contribute to the overall torque balance. Previous research by Rogister & Valette (2009) suggests that indeed rotational and gravito-inertial modes are coupled, thus shifting the frequencies of the Chandler Wobble (CW), the Free Core Nutation (FCN) and the Free Inner Core Nutation (FICN). Here we present the first results from a numerical model of the Earth's fluid core and its interaction with the rotational eigenmodes. In this first step we consider a fluid core without a solid inner core and we restrict to ellipticities of the same order as the Ekman number. We formulate the problem as a generalised eigenvalue problem that solves simultaneously the Liouville equation for the rotational modes (the torque balance), and the Navier-Stokes equation for the inertial modes.

The Large Ring Laser G for Continuous Earth Rotation Monitoring

NASA Astrophysics Data System (ADS)

Schreiber, K. U.; Klügel, T.; Velikoseltsev, A.; Schlüter, W.; Stedman, G. E.; Wells, J.-P. R.

2009-09-01

Ring Laser gyroscopes exploit the Sagnac effect and measure rotations absolute. They do not require an external reference frame and therefore provide an independent method to monitor Earth rotation. Large-scale versions of these gyroscopes promise to eventually provide a similar high resolution for the measurement of the variations in the Earth rotation rate as the established methods based on VLBI and GNSS. This would open the door to a continuous monitoring of LOD (Length of Day) and polar motion, which is not yet available today. Another advantage is the access to the sub-daily frequency regime of Earth rotation. The ring laser “G” (Grossring), located at the Geodetic Observatory Wettzell (Germany) is the most advanced realization of such a large gyroscope. This paper outlines the current sensor design and properties.

Solar rotation effects on the thermospheres of Mars and Earth.

PubMed

Forbes, Jeffrey M; Bruinsma, Sean; Lemoine, Frank G

2006-06-02

The responses of Earth's and Mars' thermospheres to the quasi-periodic (27-day) variation of solar flux due to solar rotation were measured contemporaneously, revealing that this response is twice as large for Earth as for Mars. Per typical 20-unit change in 10.7-centimeter radio flux (used as a proxy for extreme ultraviolet flux) reaching each planet, we found temperature changes of 42.0 +/- 8.0 kelvin and 19.2 +/- 3.6 kelvin for Earth and Mars, respectively. Existing data for Venus indicate values of 3.6 +/- 0.6 kelvin. Our observational result constrains comparative planetary thermosphere simulations and may help resolve existing uncertainties in thermal balance processes, particularly CO2 cooling.

Low degree Earth's gravity coefficients determined from different space geodetic observations and climate models

NASA Astrophysics Data System (ADS)

Wińska, Małgorzata; Nastula, Jolanta

2017-04-01

Large scale mass redistribution and its transport within the Earth system causes changes in the Earth's rotation in space, gravity field and Earth's ellipsoid shape. These changes are observed in the ΔC21, ΔS21, and ΔC20 spherical harmonics gravity coefficients, which are proportional to the mass load-induced Earth rotational excitations. In this study, linear trend, decadal, inter-annual, and seasonal variations of low degree spherical harmonics coefficients of Earth's gravity field, determined from different space geodetic techniques, Gravity Recovery and Climate Experiment (GRACE), satellite laser ranging (SLR), Global Navigation Satellite System (GNSS), Earth rotation, and climate models, are examined. In this way, the contribution of each measurement technique to interpreting the low degree surface mass density of the Earth is shown. Especially, we evaluate an usefulness of several climate models from the Coupled Model Intercomparison Project phase 5 (CMIP5) to determine the low degree Earth's gravity coefficients using GRACE satellite observations. To do that, Terrestrial Water Storage (TWS) changes from several CMIP5 climate models are determined and then these simulated data are compared with the GRACE observations. Spherical harmonics ΔC21, ΔS21, and ΔC20 changes are calculated as the sum of atmosphere and ocean mass effect (GAC values) taken from GRACE and a land surface hydrological estimate from the selected CMIP5 climate models. Low degree Stokes coefficients of the surface mass density determined from GRACE, SLR, GNSS, Earth rotation measurements and climate models are compared to each other in order to assess their consistency. The comparison is done by using different types of statistical and signal processing methods.

Effects of dynamic long-period ocean tides on changes in Earth's rotation rate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nam, Y.S.; Dickman, S.R.

1990-05-10

As a generalization of the zonal response coefficient first introduced by Agnew and Farrell (1978), the authors define the zonal response function k of the solid earth-ocean system as the ratio, in the frequency domain, of the tidal change in Earth's rotation rate to the tide-generating potential. Amplitudes and phases of k for the monthly, fortnightly, and 9-day lunar tides are estimated from 2 1/2 years of very long baseline interferometry UTI observations (both 5-day and daily time series), corrected for atmospheric angular momentum effects using NMC wind and pressure series. Using the dynamic ocean tide model of Dickman (1988a,more » 1989a), the authors predict amplitudes and phases of k for an elastic earth-ocean system. The predictions confirm earlier results which found that dynamic effects of the longer-period ocean tides reduce the amplitude of k by about 1%. However, agreement with the observed k is best achieved for all three tides if the predicted tide amplitudes are combined with the much larger satellite-observed ocean tide phases; in these cases the dynamic tidal effects reduce k by up to 8%. Finally, comparison between the observed and predicted amplitudes of k implies that anelastic effects on Earth's rotation at periods less than fortnightly cannot exceed 2%.« less

Station coordinates, baselines, and earth rotation from Lageos laser ranging - 1976-1984

NASA Technical Reports Server (NTRS)

Tapley, B. D.; Schultz, B. E.; Eanes, R. J.

1985-01-01

The orbit of the Lageos satellite is well suited as a reference frame for studying the rotation of the earth and the relative motion of points on the earth's crust. The satellite laser measurements can determine the location of a set of tracking stations in an appropriate terrestrial coordinate system. The motion of the earth's rotation axis relative to this system can be studied on the basis of the established tracking station locations. The present investigation is concerned with an analysis of 7.7 years of Lageos laser ranging data. In the first solution considered, the entire data span was used to adjust a single set of station positions simultaneously with orbit and earth rotation parameters. Attention is given to the accuracy of earth rotation parameters which are determined as an inherent part of the solution process.

A survey of the theory of the Earth's rotation

NASA Technical Reports Server (NTRS)

Cannon, W. H.

1981-01-01

The theory of the Earth's rotation and the geophysical phenomena affecting it is examined. First principles are reviewed and the problem of polar motion and UT1 variations is formulated in considerable generality and detail. The effects of Earth deformations and the solid Earth tides are analyzed.

Signatures of the Martian rotation parameters in the Doppler and range observables

NASA Astrophysics Data System (ADS)

Yseboodt, Marie; Dehant, Véronique; Péters, Marie-Julie

2017-09-01

The position of a Martian lander is affected by different aspects of Mars' rotational motions: the nutations, the precession, the length-of-day variations and the polar motion. These various motions have a different signature in a Doppler observable between the Earth and a lander on Mars' surface. Knowing the correlations between these signatures and the moments when these signatures are not null during one day or on a longer timescale is important to identify strategies that maximize the geophysical return of observations with a geodesy experiment, in particular for the ones on-board the future NASA InSight or ESA-Roscosmos ExoMars2020 missions. We provide first-order formulations of the signature of the rotation parameters in the Doppler and range observables. These expressions are functions of the diurnal rotation of Mars, the lander position, the planet radius and the rotation parameter. Additionally, the nutation signature in the Doppler observable is proportional to the Earth declination with respect to Mars. For a lander on Mars close to the equator, the motions with the largest signature in the Doppler observable are due to the length-of-day variations, the precession rate and the rigid nutations. The polar motion and the liquid core signatures have a much smaller amplitude. For a lander closer to the pole, the polar motion signature is enhanced while the other signatures decrease. We also numerically evaluate the amplitudes of the rotation parameters signature in the Doppler observable for landers on other planets or moons.

Effects of Long Period Ocean Tides on the Earth's Rotation

NASA Technical Reports Server (NTRS)

Gross, Richard S.; Chao, Ben F.; Desai, Shailen D.

1996-01-01

The spectra of polar motion excitation functions exhibit enhanced power in the fortnightly tidal band. This enhanced power is attributed to ocean tidal excitation. Ocean tide models predict polar motion excitation effects that differ with each other, and with observations, by factors as large as 2-3. There is a need for inproved models for the effect of long-period ocean tides on Earth's rotation.

The Global Non-Holonomity of the Rotating Space of the Earth Affects Hafele-Keating Experiment

NASA Astrophysics Data System (ADS)

Rabounski, Dmitri; Borissova, Larissa

2013-04-01

The deviation of time registered in the ``around-the-world clocks experiment'' (Hafele J. and Keating R., Science, 14 July 1972, 166-170) is originally explained due to: 1) General Relativity (gravitation is lower at the flying airplane's altitude); 2) Special Relativity (the airplane's speed and the Earth's rotation). However as was shown in the 1940's by Schouten and then Zelmanov, if the observer cannot be moved to the rotation-free frame, the space rotation is a non-vanishing effect of General Relativity, and is due to the non-holonomity of space (the non-orthogonality of the three-space to the lines of time). This is the case of Hafele-Keating experiment (the Earth's rotation cannot be stopped). We thus constructed the metric of the real space of the Earth which bears the gravitational field and rotation. We then proved that this metric satisfies Einstein's equations. Finally, an exact formula is deduced for Hafele-Keating experiment. Despite a hundred nanoseconds of the time correction, and the use of the GPS navigation, the obtained result is useful in the case where is no the GPS connexion, in a long-term submarine travel for instance.

Earth rotation measured by lunar laser ranging

NASA Technical Reports Server (NTRS)

Stolz, A.; Bender, P. L.; Faller, J. E.; Silverberg, E. C.; Mulholland, J. D.; Shelus, P. J.; Williams, J. G.; Carter, W. E.; Currie, D. G.; Kaula, V. M.

1976-01-01

The estimated median accuracy of 194 single-day determinations of the earth's angular position in space is 0.7 millisecond (0.01 arc second). Comparison with classical astronomical results gives agreement to about the expected 2-millisecond uncertainty of the 5-day averages obtained by the Bureau International de l'Heure. Little evidence for very rapid variations in the earth's rotation is present in the data.

Near-Earth Asteroid Physical Observations: 1993-1995

NASA Astrophysics Data System (ADS)

Skiff, B. A.; Buie, M. W.; Bowell, E.

1996-09-01

In September 1993, we initiated a regular program of photometric observations of Near-Earth objects. Since that time we have been allocated 5-7 nights per month at the 42'' Hall telescope at Anderson Mesa. There are three goals of our observing program for each asteroid: (1) to obtain an accurate rotation period and characterization of the lightcurve, (2) to obtain the surface color, and (3) to measure the photometric parameters, H and G. All of the lightcurve observations are made in Kron-Cousins R and we always obtain a V-R color. Limited ECAS colors are also obtained when the objects are bright enough. We have secured periods for 9 asteroids, 1864 Daedalus, 1866 Sisyphus, 3200 Phaethon, 4954 Eric, 5693 (1993 EA), 5836 (1993 MF), 6489 (1991 JX), 1993 QP, and 1993 WD. Some of these periods are a confimation of an earlier result but most are new. We obtained colors for all these objects as well as four additional asteroids, 5407 (1992 AX), 1993 UC, 1993 VW, and 1994 LW. We have additional (as yet unreduced) observations of 2062 Aten, 2212 Hephaistos, 3752 Camillo, 5143 Heracles, 5863 (1983 RB), 6053 (1993 BW3), 7025 (1993 QA), 7092 (1992 LC), 1989 VA, 1992 TC, 1994 RC, and 1995 YA3. The fastest rotation period we find is 2.402 hours for 1866 Sisyphus and the slowest is 93QP at ~ 24 hours. The colors for these objects range from V-R=0.34 for 3200 Phaethon to V-R=0.49 for 1866 Sisyphus and 4954 Eric. Most colors fall near V-R=0.43. These observations should help to provide a more complete understanding of the surface properties and rotational states of the Near-Earth asteroids. This work was supported by NASA Grant NAGW-1470.

Co-Seismic Mass Dislocation and its Effect on Earth's Rotation and Gravity

NASA Technical Reports Server (NTRS)

Chao, B. F.; Gross, R. S.

2002-01-01

Mantle processes often involve large-scale mass transport, ranging from mantle convection, tectonic motions, glacial isostatic adjustment, to tides, atmospheric and oceanic loadings, volcanism and seismicity. On very short time scale of less than an hour, co-seismic event, apart from the shaking that is the earthquake, leaves behind permanent (step-function-like) dislocations in the crust and mantle. This redistribution of mass changes the Earth's inertia tensor (and hence Earth's rotation in both length-of-day and polar motion), and the gravity field (in terms of spherical harmonic Stokes coefficients). The question is whether these effects are large enough to be of any significance. In this paper we report updated calculation results based on Chao & Gross (1987). The calculation uses the normal mode summation scheme, applied to nearly twenty thousand major earthquakes that occurred during 1976-2002, according to source mechanism solutions given by the Harvard Central Moment Tensor catalog. Compared to the truly large ones earlier in the century, the earthquakes we study are individually all too small to have left any discernible signature in geodetic records of Earth rotation or global gravity field. However, their collective effects continue to exhibit an extremely strong statistical tendencies. For example, earthquakes conspire to decrease J2 and J22 while shortening LOD, resulting in a rounder and more compact Earth. Strong tendency is also seen in the earthquakes trying to nudge the Earth rotation pole towards approximately 140 degrees E, roughly opposite to the observed polar drift direction. The geophysical significance and implications will be further studied.

Co-Seismic Mass Dislocation and Its Effect on Earth's Rotation and Gravity

NASA Technical Reports Server (NTRS)

Chao, Benjamin F.

1999-01-01

Mantle processes often involve large-scale mass transport, ranging from mantle convection, tectonic motions, glacial isostatic adjustment, to tides, atmospheric and oceanic loadings, volcanism and seismicity. On very short time scale of less than an hour, co-seismic event, apart from the "shaking" that is the earthquake, leaves behind permanent (step-function-like) dislocations in the crust and mantle. This redistribution of mass changes the Earth's inertia tensor (and hence Earth's rotation in both length-of-day and polar motion), and the gravity field (in terms of spherical harmonic Stokes coefficients). The question is whether these effects are large enough to be of any significance. In this paper we report updated calculation results. The calculation uses the normal mode summation scheme, applied to 15,814 major earthquakes that occurred during 1976-1998, according to source mechanism solutions given by the Harvard Central Moment Tensor catalog. Compared to the truly large ones earlier in the century, the earthquakes we study are individually all too small to have left any discernible signature in geodetic records of Earth rotation or global gravity field. However, their collective effects continue to exhibit an extremely strong statistical tendencies. For example, earthquakes conspire to decrease J(sub 2) and J(sub 22) while shortening LOD, resulting in a rounder and more compact Earth. Strong tendency is also seen in the earthquakes trying to "nudge" the Earth rotation pole towards about 140 degree E, roughly opposite to the observed polar drift direction. The geophysical significance and implications will be further studied.

The Earth rotation and revolution effect on the daily and annual variation of sporadic meteor echo

NASA Astrophysics Data System (ADS)

Ohnishi, Kouji; Hattori, Shinobu; Nishimura, Osamu; Ishikawa, Toshiyuki; Aoki, Yoshie; Iijima, Yukiko; Kobayashi, Aya; Maegawa, Kimio; Abe, Shinsuke

2001-11-01

The Earth rotation and revolution will affect the daily and annual variation of sporadic meteor echo. We try to investigate such effect using Ham-band Radio Observation (HRO). Our system is constructed with paired two-element loop antennas (F/B ratio is 10 dB) at Nagano, Japan using the beacon signals at 53.750 MHz, 50W from Sabae, Fukui, Japan. The direction of one of this paired antenna was West toward Sagae and the other was East, so that this system could be roughly detected the direction of the reflected radio echoes. Using this system, (1) The total echo rose from midnight with the peak coming at about 6:00 and decreasing to the noon. This is well known daily variation due to the Earth rotation. (2) The peak echoes time by Eastward antenna and by Westward antennas was different; Westward was at 3:00 and Eastward was at 10:00. This daily variation is interpreted as the effect of the Earth rotation and revolution and the specular reflection property of forward meteor scattering observation.

Differential Rotation within the Earth's Outer Core

NASA Technical Reports Server (NTRS)

Hide, R.; Boggs, D. H.; Dickey, J. O.

1998-01-01

Non-steady differential rotation drive by bouyancy forces within the Earth's liquid outer core (OC) plays a key role not only in the generation of the main geomagnetic field by the magnetohydrodynamic (MHD) dynamo process but also in the excitation of irregular fluctuations in the angular speed of rotation of the overlying solid mantle, as evidenced by changes in the length of the day (LOD) on decadal and longer timescales (1-8).

Interaction of the Climate System and the Solid Earth: Analysis of Observations and Models

NASA Technical Reports Server (NTRS)

Bryan, Frank

2001-01-01

Under SENH funding we have carried out a number of diverse analyses of interactions of the climate system (atmosphere, ocean, land surface hydrology) with the solid Earth. While the original work plan emphasized analysis of excitation of variations in Earth rotation, with a lesser emphasis on time variable gravity, opportunities that developed during the proposal period in connection with preparations for the GRACE mission led us to a more balanced effort between these two topics. The results of our research are outlined in several topical sections: (1) oceanic excitation of variations in Earth rotation; (2) short period atmosphere-ocean excitation of variations in Earth rotation; (3) analysis of coupled climate system simulation; (4) observing system simulation studies for GRACE mission design; and (5) oceanic response to atmospheric pressure loading.

Observations of Near-Earth Asteroids in Polarized Light

NASA Astrophysics Data System (ADS)

Afanasiev, V. L.; Ipatov, A. V.

2018-04-01

We report the results of position, photometric, and polarimetric observations of two near-Earth asteroids made with the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences. 1.2-hour measurements of the photometric variations of the asteroid 2009 DL46 made onMarch 8, 2016 (approximately 20m at a distance of about 0.23 AU from the Earth) showed a 0.m2-amplitude flash with a duration of about 20 minutes. During this time the polarization degree increased from the average level of 2-3% to 14%. The angle of the polarization plane and the phase angle were equal to 113° ± 1° and 43°, respectively. Our result indicates that the surface of the rotating asteroid (the rotation period of about 2.5 hours) must be non-uniformly rough. Observations of another asteroid—1994 UG—whose brightness was of about 17m and which was located at a geocentric distance of 0.077 AU, were carried out during the night of March 6/7, 2016 in two modes: photometric and spectropolarimetric. According to the results of photometric observations in Johnson's B-, V-, and R-band filters, over one hour the brightness of the asteroid remained unchanged within the measurement errors (about 0.m02). Spectropolarimetric observations in the 420-800 nm wavelength interval showed the polarization degree to decrease from 8% in the blue part of the spectrum to 2% in the red part with the phase angle equal to 44°, which is typical for S-type near-Earth asteroids.

Earth's rotation in the framework of general relativity: rigid multipole moments

NASA Astrophysics Data System (ADS)

Klioner, S. A.; Soffel, M.; Xu, Ch.; Wu, X.

A set of equations describing the rotational motion of the Earth relative to the GCRS is formulated in the approximation of rigidly rotating multipoles. The external bodies are supposed to be mass monopoles. The derived set of formulas is supposed to form the theoretical basis for a practical post-Newtonian theory of Earth precession and nutation.

Division A Commission 19: Rotation of the Earth

NASA Astrophysics Data System (ADS)

Huang, Chengli; Gross, Richard; Seitz, Florian; Schuh, Harald; Bizouard, Christian; Chao, Ben; Kosek, Wieslaw; Salstein, David; Zharov, Vladimir; Titov, Oleg; Richter, Bernd; Malkin, Zinovy

2016-04-01

The activities and some research progress of IAU Commission 19 (C19) - Rotation of the Earth - in the past triennial term (2012-2015) is reported in this paper, including the scientific session and business meeting of C19, as well as a business meeting of the IAU/IAG Joint Working Group of ``Theory of Earth Rotation'' (JWG_ThER) during the XXIX IAU General Assembly in Hawaii, USA. Three reports of JWG_ThER progress, IERS and IAG, eleven reports of national projects and individual institutions, a short summary of the history and heritage of C19, and an Overview of the status and outlook of new Commission A2 are also presented.

A Numerical-Analytical Approach to Modeling the Axial Rotation of the Earth

NASA Astrophysics Data System (ADS)

Markov, Yu. G.; Perepelkin, V. V.; Rykhlova, L. V.; Filippova, A. S.

2018-04-01

A model for the non-uniform axial rotation of the Earth is studied using a celestial-mechanical approach and numerical simulations. The application of an approximate model containing a small number of parameters to predict variations of the axial rotation velocity of the Earth over short time intervals is justified. This approximate model is obtained by averaging variable parameters that are subject to small variations due to non-stationarity of the perturbing factors. The model is verified and compared with predictions over a long time interval published by the International Earth Rotation and Reference Systems Service (IERS).

High-Accuracy Ring Laser Gyroscopes: Earth Rotation Rate and Relativistic Effects

NASA Astrophysics Data System (ADS)

Beverini, N.; Di Virgilio, A.; Belfi, J.; Ortolan, A.; Schreiber, K. U.; Gebauer, A.; Klügel, T.

2016-06-01

The Gross Ring G is a square ring laser gyroscope, built as a monolithic Zerodur structure with 4 m length on all sides. It has demonstrated that a large ring laser provides a sensitivity high enough to measure the rotational rate of the Earth with a high precision of ΔΩE < 10-8. It is possible to show that further improvement in accuracy could allow the observation of the metric frame dragging, produced by the Earth rotating mass (Lense-Thirring effect), as predicted by General Relativity. Furthermore, it can provide a local measurement of the Earth rotational rate with a sensitivity near to that provided by the international system IERS. The GINGER project is intending to take this level of sensitivity further and to improve the accuracy and the long-term stability. A monolithic structure similar to the G ring laser is not available for GINGER. Therefore the preliminary goal is the demonstration of the feasibility of a larger gyroscope structure, where the mechanical stability is obtained through an active control of the geometry. A prototype moderate size gyroscope (GP-2) has been set up in Pisa in order to test this active control of the ring geometry, while a second structure (GINGERino) has been installed inside the Gran Sasso underground laboratory in order to investigate the properties of a deep underground laboratory in view of an installation of a future GINGER apparatus. The preliminary data on these two latter instruments are presented.

The effect of the earth's rotation on ground water motion.

PubMed

Loáiciga, Hugo A

2007-01-01

The average pore velocity of ground water according to Darcy's law is a function of the fluid pressure gradient and the gravitational force (per unit volume of ground water) and of aquifer properties. There is also an acceleration exerted on ground water that arises from the Earth's rotation. The magnitude and direction of this rotation-induced force are determined in exact mathematical form in this article. It is calculated that the gravitational force is at least 300 times larger than the largest rotation-induced force anywhere on Earth, the latter force being maximal along the equator and approximately equal to 34 N/m(3) there. This compares with a gravitational force of approximately 10(4) N/m(3).

Development of a new model for short period ocean tidal variations of Earth rotation

NASA Astrophysics Data System (ADS)

Schuh, Harald

2015-08-01

Within project SPOT (Short Period Ocean Tidal variations in Earth rotation) we develop a new high frequency Earth rotation model based on empirical ocean tide models. The main purpose of the SPOT model is its application to space geodetic observations such as GNSS and VLBI.We consider an empirical ocean tide model, which does not require hydrodynamic ocean modeling to determine ocean tidal angular momentum. We use here the EOT11a model of Savcenko & Bosch (2012), which is extended for some additional minor tides (e.g. M1, J1, T2). As empirical tidal models do not provide ocean tidal currents, which are re- quired for the computation of oceanic relative angular momentum, we implement an approach first published by Ray (2001) to estimate ocean tidal current veloci- ties for all tides considered in the extended EOT11a model. The approach itself is tested by application to tidal heights from hydrodynamic ocean tide models, which also provide tidal current velocities. Based on the tidal heights and the associated current velocities the oceanic tidal angular momentum (OTAM) is calculated.For the computation of the related short period variation of Earth rotation, we have re-examined the Euler-Liouville equation for an elastic Earth model with a liquid core. The focus here is on the consistent calculation of the elastic Love num- bers and associated Earth model parameters, which are considered in the Euler- Liouville equation for diurnal and sub-diurnal periods in the frequency domain.

Co-Seismic Mass Displacement and its Effect on Earth's Rotation and Gravity

NASA Technical Reports Server (NTRS)

Chao, B. F.; Gross, R. S.

2004-01-01

Mantle processes often involve large-scale mass transport, ranging from mantle convection, tectonic motions, glacial isostatic adjustment, to tides, atmospheric and oceanic loadings, volcanism and seismicity. On very short time scale of less than an hour, co-seismic event, apart from the "shaking" that is the earthquake, leaves behind permanent (step-function-like) displacements in the crust and mantle. This redistribution of mass changes the Earth's inertia tensor (and hence Earth's rotation in both length-of-day and polar motion), and the gravity field. The question is whether these effects are large enough to be of any significance. In this paper we report updated calculation results based on Chao & Gross. The calculation uses the normal mode summation scheme, applied to over twenty thousand major earthquakes that occurred during 1976-2002, according to source mechanism solutions given by the Harvard Centroid Moment Tensor catalog. Compared to the truly large ones earlier in the century, the earthquakes we study are individually all too small to have left any discernible signature in geodetic records of Earth rotation or global gravity field. However, their collective effects continue to exhibit an extremely strong statistical tendencies, conspiring to decrease J2 and J22 while shortening LOD, resulting in a rounder and more compact Earth. Strong tendency is also seen in the earthquakes trying to "nudge" the Earth rotation pole towards approx. 140 deg.E, roughly opposite to the observed polar drift direction. Currently, the Gravity Recovery And Climate Experiment (GRACE) is measuring the time-variable gravity to high degree and order with unprecedented accuracy. Our results show that great earthquakes such as the 1960 Chilean or 1964 Alaskan events cause gravitational field changes that are large enough to be detected by GRACE.

Earth observing satellite: Understanding the Earth as a system

NASA Technical Reports Server (NTRS)

Soffen, Gerald

1990-01-01

There is now a plan for global studies which include two very large efforts. One is the International Geosphere/Biosphere Program (IGBP) sponsored by the International Council of Scientific Unions. The other initiative is Mission to Planet Earth, an unbrella program for doing three kinds of space missions. The major one is the Earth Observation Satellite (EOS). EOS is large polar orbiting satellites with heavy payloads. Two will be placed in orbit by NASA, one by the Japanese and one or two by ESA. The overall mission measurement objectives of EOS are summarized: (1) the global distribution of energy input to and energy output from the Earth; (2) the structure, state variables, composition, and dynamics of the atmosphere from the ground to the mesopause; (3) the physical and biological structure, state, composition, and dynamics of the land surface, including terrestrial and inland water ecosystems; (4) the rates, important sources and sinks, and key components and processes of the Earth's biogeochemical cycles; (5) the circulation, surface temperature, wind stress, sea state, and the biological activity of the oceans; (6) the extent, type, state, elevation, roughness, and dynamics of glaciers, ice sheets, snow and sea ice, and the liquid equivalent of snow in the global cryosphere; (7) the global rates, amounts, and distribution of precipitation; and (8) the dynamic motions of the Earth (geophysics) as a whole, including both rotational dynamics and the kinematic motions of the tectonic plates.

Earthquake triggering, Earth's rotation variations, Meton's cycle and torques acting on the Earth.

NASA Astrophysics Data System (ADS)

Ostrihansky, L.

2012-04-01

In contrast to unsuccessful searching (lasting over 150 years) of correlation of earthquakes with biweekly tides the author found correlation of earthquakes with sidereal 13.66 days Earth's rotation variations expressed as the length of a day (LOD) measured daily by the International Earth's Rotation Service. After short mention about earthquakes Denali Fault Alaska 3rd November 2002, M 7.9, triggered on LOD maximum and Great Sumatra earthquake 26th December 2004 triggered on LOD minimum and the full Moon, the main object of this paper are earthquakes of period 2010-VI. 2011: Haiti M 7.0 Jan. 12, 2010 on LOD minimum, Maule Chile M 8.8 Feb. 12, 2010 on LOD maximum, Sumatra and Andaman Sea region 6 earthquakes revealed from 7 on LOD minimum, New Zealand, Christchurch M 7.1 Sep. 9, 2010 on LOD minimum and Christchurch M 6.3 Feb. 21, 2011 on LOD maximum and Japan Near coast of Honshu M 9.1 March 11, 2011 on LOD minimum. I found that LOD minimums coincide with full or new Moon only twice in a year in solstices and also twice in the year with LOD maximums in equinoxes. To prove that determined coincidences of earthquakes and LOD extremes stated above are not accidental events, histograms were constructed of earthquake occurrence and their position on LOD graph deeply in the past, in some cases from the time the IERS started to measure the Earth's rotation variations in 1962. Evaluation of histograms and the Schuster's test has proven that maxima of earthquakes are triggered always in both Earth's rotation deceleration and acceleration. Backward overview of the past earthquakes revealed that the Great Sumatra earthquake Dec. 26, 2004 had its equivalent in the shape of LOD graph, full Moon position, character of aftershocks, 19 years ago in difference only one day of Dec. 27, 1985 M 6.6, proving that not only sidereal 13.66 days variations but also the 19 years Meton's cycle is the period of the earthquakes occurrence.

High-frequency Faraday rotation observations of the solar corona

NASA Astrophysics Data System (ADS)

Jensen, Elizabeth A.; Russell, Christopher T.

2008-10-01

This thesis, presented on January 31, 2007 under the supervision of Professor Christopher T. Russell, discusses the solar coronal magnetic field observations that can be obtained using the phenomenon of Faraday rotation. It was defended in the Department of Earth and Space Sciences at the University of California, Los Angeles (595 Charles E. Young, Dr. East, Los Angeles, CA 90095). A resume can be found at http://acs-consulting.com/.

New Estimates of Hydrological and Oceanic Excitations of Variations of Earth's Rotation, Geocenter and Gravitational Field

NASA Technical Reports Server (NTRS)

Chao, Benjamin F.; Chen, J. L.; Johnson, T.; Au, A. Y.

1998-01-01

Hydrological mass transport in the geophysical fluids of the atmosphere-hydrosphere-solid Earth surface system can excite Earth's rotational variations in both length-of-day and polar motion. These effects can be computed in terms of the hydrological angular momentum by proper integration of global meteorological data. We do so using the 40-year NCEP data and the 18-year NASA GEOS-1 data, where the precipitation and evapotranspiration budgets are computed via the water mass balance of the atmosphere based on Oki et al.'s (1995) algorithm. This hydrological mass redistribution will also cause geocenter motion and changes in Earth's gravitational field, which are similarly computed using the same data sets. Corresponding geodynamic effects due to the oceanic mass transports (i.e. oceanic angular momentum and ocean-induced geocenter/gravity changes) have also been computed in a similar manner. We here compare two independent sets of the result from: (1) non-steric ocean surface topography observations based on Topex/Poseidon, and (2) the model output of the mass field by the Parallel Ocean Climate Model. Finally, the hydrological and the oceanic time series are combined in an effort to better explain the observed non-atmospheric effects. The latter are obtained by subtracting the atmospheric angular momentum from Earth rotation observations, and the atmosphere- induced geocenter/gravity effects from corresponding geodetic observations, both using the above-mentioned atmospheric data sets.

A Potpourri of Near-Earth Asteroid Observations

NASA Astrophysics Data System (ADS)

Tholen, David J.; Ramanjooloo, Yudish; Fohring, Dora; Hung, Denise; Micheli, Marco

2016-10-01

Ongoing astrometric follow-up of near-Earth asteroids has yielded a variety of interesting results. In the limited space of a DPS abstract, three recently observed objects are worth mentioning.2008 HU4 is among the most accessible asteroids for a human space flight mission. We successfully recovered this object at a second opposition on 2016 April 26 despite the large ephemeris uncertainty. The small size of this asteroid makes it relatively easy to detect the departure from purely gravitational motion caused by solar radiation pressure, which can be used to estimate the density of the object. At the time of this writing, the object remains bright enough for additional observations, so we expect to improve on our five-sigma detection of a relatively low density (roughly similar to water, indicating a high porosity) between now and the DPS meeting.2016 HO3 is a newly-discovered co-orbital with the Earth. Our 2016 May 10-11 observations extended the observational arc by enough to permit backward extrapolation that led to prediscovery observations by Pan-STARRS in 2015, and then annually back to 2011, and ultimately to Sloan DSS observations in 2004. The 12-year arc is sufficient to examine the dynamical behavior of the object, which shows how it will remain in the vicinity of the Earth for decades, if not centuries. Our observations also revealed a rapid rotation (less than a half hour) with large brightness variation (in excess of 1 magnitude), which helps to explain why this object eluded discovery until this year.2011 YV62 is among the top 20 largest near-Earth asteroids with Earth impact solutions (in 2078 and 2080). At the time of this writing, the object is flagged as being "lost", but a re-examination of observations made in 2013 and 2015 finally yielded a successful recovery at a magnitude fainter than 24. We expect the new observations to eliminate the impact possibilities. The story behind this difficult recovery is fascinating.

Crew Earth Observations

NASA Technical Reports Server (NTRS)

Runco, Susan

2009-01-01

Crew Earth Observations (CEO) takes advantage of the crew in space to observe and photograph natural and human-made changes on Earth. The photographs record the Earth's surface changes over time, along with dynamic events such as storms, floods, fires and volcanic eruptions. These images provide researchers on Earth with key data to better understand the planet.

Earth System Dynamics: The Determination and Interpretation of the Global Angular Momentum Budget using the Earth Observing System. Revised

NASA Technical Reports Server (NTRS)

2003-01-01

The objective of this investigation has been to examine the mass and momentum exchange between the atmosphere, oceans, solid Earth, hydrosphere, and cryosphere. The investigation has focused on changes in the Earth's gravity field, its rotation rate, atmospheric and oceanic circulation, global sea level change, ice sheet change, and global ground water circulation observed by contemporary sensors and models. The primary component of the mass exchange is water. The geodetic observables provided by these satellite sensors are used to study the transport of water mass in the hydrological cycle from one component of the Earth to another, and they are also used to evaluate the accuracy of models. As such, the investigation is concerned with the overall global water cycle. This report provides a description of scientific, educational and programmatic activities conducted during the period July 1, 1999 through June 30,2000. Research has continued into measurements of time-varying gravity and its relationship to Earth rotation. Variability of angular momentum and the related excitation of polar motion and Earth rotation have been examined for the atmosphere and oceans at time-scales of weeks to several years. To assess the performance of hydrologic models, we have compared geodetic signals derived from them with those observed by satellites. One key component is the interannual mass variability of the oceans obtained by direct observations from altimetry after removing steric signals. Further studies have been conducted on the steric model to quantify its accuracy at global and basin-scales. The results suggest a significant loss of water mass from the Oceans to the land on time-scales longer than 1-year. These signals are not reproduced in any of the models, which have poorly determined interannual fresh water fluxes. Output from a coupled atmosphere-ocean model testing long-term climate change hypotheses has been compared to simulated errors from the Gravity Recovery and

Rotational Period Determination for 12 Near-Earth Asteroids

NASA Astrophysics Data System (ADS)

Monteiro, Filipe; Arcoverde, Plicida; Medeiros, Hissa; Rondon, Eduardo; Souza, Roberto; Rodrigues, Tersinha; Lazzaro, Daniela

2018-07-01

Rotational periods for 12 near-Earth asteroids (NEAs) were determined from lightcurves acquired at the Observatório Astronômico do Sertão de Itaparica (MPC Y28, OASI) between May 2016 and 2017 August.

Reference Frames in Earth Rotation Theories

NASA Astrophysics Data System (ADS)

Ferrándiz, José M.; Belda, Santiago; Heinkelmann, Robert; Getino, Juan; Schuh, Harald; Escapa, Alberto

2015-04-01

Nowadays the determination of the Earth Orientation Parameters (EOP) and the different Terrestrial Reference Frames (TRF) are not independent. The available theories of Earth rotation aims at providing the orientation of a certain reference system linked somehow to the Earth with respect to a given celestial system, considered as inertial. In the past years a considerable effort has been dedicated to the improvement of the TRF realizations, following the lines set up in the 1980's. However, the reference systems used in the derivation of the theories have been rather considered as something fully established, not deserving a special attention. In this contribution we review the definitions of the frames used in the main theoretical approaches, focusing on those used in the construction of IAU2000, and the extent to which their underlying hypotheses hold. The results are useful to determine the level of consistency of the predicted and determined EOP.

Influence of ocean tides on the diurnal and semidiurnal earth rotation variations from VLBI observations

NASA Astrophysics Data System (ADS)

Gubanov, V. S.; Kurdubov, S. L.

2015-05-01

The International astrogeodetic standard IERS Conventions (2010) contains a model of the diurnal and semidiurnal variations in Earth rotation parameters (ERPs), the pole coordinates and the Universal Time, arising from lunisolar tides in the world ocean. This model was constructed in the mid-1990s through a global analysis of Topex/Poseidon altimetry. The goal of this study is to try to estimate the parameters of this model by processing all the available VLBI observations on a global network of stations over the last 35 years performed within the framework of IVS (International VLBI Service) geodetic programs. The complexity of the problemlies in the fact that the sought-for corrections to the parameters of this model lie within 1 mm and, thus, are at the limit of their detectability by all currently available methods of ground-based positional measurements. This requires applying universal software packages with a high accuracy of reduction calculations and a well-developed system of controlling the simultaneous adjustment of observational data to analyze long series of VLBI observations. This study has been performed with the QUASAR software package developed at the Institute of Applied Astronomy of the Russian Academy of Sciences. Although the results obtained, on the whole, confirm a high accuracy of the basic model in the IERS Conventions (2010), statistically significant corrections that allow this model to be refined have been detected for some harmonics of the ERP variations.

Monitoring of Earth Rotation by VLBI

NASA Technical Reports Server (NTRS)

Ma., Chopo; Macmillan, D. S.

2000-01-01

Monitoring Earth rotation with Very Long Baseline Interferometry (VLBI) has unique potential because of direct access to the Celestial Reference System (CRF and Terrestrial Reference System (TRF) and the feasibility of re-analyzing the entire data set. While formal precision of better than 0.045 mas for pole and 0.002 ms for UT 1 has been seen in the best 24-hr data, the accuracy of the Earth Orientation Parameter (EOP) time series as a whole is subject to logistical, operational, analytical and conceptual constraints. The current issues related to the VLBI data set and the CORE program for greater time resolution such as analysis consistency, network jitter and reference frame stability will be discussed.

Observations of Heliospheric Faraday Rotation (FR) and Interplanetary Scintillation (IPS): Steps Towards Investigating Bz Propagation Between the Sun and the Earth

NASA Astrophysics Data System (ADS)

Bisi, Mario M.; Fallows, Richard A.; Sobey, Charlotte; Eftekhari, Tarraneh; Jensen, Elizabeth A.; Jackson, Bernard V.; Yu, Hsiu-Shan; Hick, P. Paul; Odstrcil, Dusan; Tokumaru, Munetoshi; Oyuki Chang, M. T.

2016-04-01

Space weather - analogous to terrestrial weather (describing the changing pressure, temperature, wind, and humidity conditions on Earth) - is essentially a description of the changes in velocity, density, magnetic field, high-energy particles, and radiation in the near-Earth space environment including the effects of such on the Earth. Space weather can be considered to have two main strands: (i) scientific research, and (ii) applications. The former is self-explanatory, but the latter covers operational aspects including forecasting. Understanding and forecasting space weather near the Earth is of critical importance to protecting our modern-day reliance on satellites, global-communications and navigation networks, high-altitude air travel (radiation concerns particularly on polar routes), long-distance power/oil/gas lines and piping, and for any future human exploration of space to list but a few. This includes both military and commercial considerations. Two ground-based radio-observing techniques that can add to and lead our understanding and forecasting of heliospheric space weather are those of interplanetary scintillation (IPS) and heliospheric Faraday rotation (FR). We present our latest progress using these two radio heliospheric-imaging remote-sensing techniques including the use of three-dimensional (3-D) modelling and reconstruction techniques using other, additional data as input to support and better-interpret individual case-study results.

Arecibo Radar Observations of Near-Earth Asteroids: A Study in Heterogeneity

NASA Technical Reports Server (NTRS)

Nolan, M. C.; Howell, E. S.; Margot J.-L.; Ostro, S. J; Benner, L. A. M.; Giorgini, J. D.; Campbell, D. B.

2002-01-01

Characterization of the rotation state and structure of near-Earth asteroids through radar observations using the Arecibo and Goldstone planetary radar systems shows the remarkable variety of these objects, and suggests variety of formation and modification mechanisms. Additional information is contained in the original extended abstract.

Excitation of the earth's rotational axis by recent glacial discharges

NASA Technical Reports Server (NTRS)

Gasperini, P.; Sabadini, R.; Yuen, D. A.

1986-01-01

The effects of present-day glacial discharges and the growth of the Antarctic ice sheet on exciting the earth's rotational axis are studied. Glacial forcing could cause a maximum change in J2 of about one-third of the observed amount, for the Maxwell rheology and for Burgers' body models with a long-term, lower-mantle viscosity greater than about 10 to the 23rd P. For transient rheologies the amount of excitation due to glacial melting decreases. Polar wander is not much excited by recent glacial melting for the various types of rheologies examined.

The Effects Of Earth’s Rotation On The Late Submarine Wake

DTIC Science & Technology

2017-12-01

had never before encountered. His practical knowledge and real-world experience were beneficial to not only this project, but to numerous other...rotation of the earth. Long-lived vortices were observed during these laboratory experiments , however both the vortices and wakes remained fairly...symmetric. In spite of this, Spedding 2 acknowledged that wakes and vortices in the ocean experience forcing not present in the laboratory and that real

Atmospheric effects on earth rotation and polar motion

NASA Technical Reports Server (NTRS)

Salstein, David A.

1988-01-01

The variability in the earth's rotation rate not due to known solid body tides is dominated on time scales of about four years and less by variations in global atmospheric angular momentum (M) as derived from the zonal wind distribution. Among features seen in the length of day record produced by atmospheric forcing are the strong seasonal cycle, quasi-periodic fluctuations around 40-50 days, and an interannual signal forced by a strong Pacific warming event known as the El Nino. Momentum variations associated with these time scales arise in different latitudinal regions. Furthermore, winds in the stratosphere make a particularly important contribution to seasonal variability. Other related topics discussed here are: (1) comparisons of the M series from wind fields produced at different weather centers; (2) the torques that dynamically link the atmosphere and earth; and (3) longer-term nonatmospheric effects that can be seen upon removal of the atmospheric signal.an interestigapplication for climatological purposes is the use of the historical earth rotation series as a proxy for atmospheric wind variability prior to the era of upper-air data. Lastly, results pertaining to the role of atmospheric pressure systems in exciting rapid polar motion are presented.

On the Long-Term "Hesitation Waltz" Between the Earth's Figure and Rotation Axes

NASA Astrophysics Data System (ADS)

Couhert, A.; Mercier, F.; Bizouard, C.

2017-12-01

The principal figure axis of the Earth refers to its axis of maximum inertia. In the absence of external torques, the latter should closely coincide with the rotation pole, when averaged over many years. However, because of tidal and non-tidal mass redistributions within the Earth system, the rotational axis executes a circular motion around the figure axis essentially at seasonal time scales. In between, it is not clear what happens at decadal time spans and how well the two axes are aligned. The long record of accurate Satellite Laser Ranging (SLR) observations to Lageos makes possible to directly measure the long time displacement of the figure axis with respect to the crust, through the determination of the degree 2 order 1 geopotential coefficients for the 34-year period 1983-2017. On the other hand, the pole coordinate time series (mainly from GNSS and VLBI data) yield the motion of the rotation pole with even a greater accuracy. This study is focused on the analysis of the long-term behavior of the two time series, as well as the derivation of possible explanations for their discrepancies.

International Space Station Earth Observations Working Group

NASA Technical Reports Server (NTRS)

Stefanov, William L.; Oikawa, Koki

2015-01-01

The multilateral Earth Observations Working Group (EOWG) was chartered in May 2012 in order to improve coordination and collaboration of Earth observing payloads, research, and applications on the International Space Station (ISS). The EOWG derives its authority from the ISS Program Science Forum, and a NASA representative serves as a permanent co-chair. A rotating co-chair position can be occupied by any of the international partners, following concurrence by the other partners; a JAXA representative is the current co-chair. Primary functions of the EOWG include, 1) the exchange of information on plans for payloads, from science and application objectives to instrument development, data collection, distribution and research; 2) recognition and facilitation of opportunities for international collaboration in order to optimize benefits from different instruments; and 3) provide a formal ISS Program interface for collection and application of remotely sensed data collected in response to natural disasters through the International Charter, Space and Major Disasters. Recent examples of EOWG activities include coordination of bilateral data sharing protocols between NASA and TsNIIMash for use of crew time and instruments in support of ATV5 reentry imaging activities; discussion of continued use and support of the Nightpod camera mount system by NASA and ESA; and review and revision of international partner contributions on Earth observations to the ISS Program Benefits to Humanity publication.

Measuring the earth's rotation and orientation with GPS

NASA Technical Reports Server (NTRS)

Freedman, Adam P.

1992-01-01

The possibilities for providing precise and frequent measurements of earth's orientation in space by using GPS technology are reviewed. In particular, attention is given to the concepts as polar motion and Universal Time, definition of reference frames for unambiguous measurements of earth's rotations, and data processing strategies. Some of the results achieved to date are examined, and it is shown that Universal Time changes can be measured using GPS with an accuracy of better than 100 microseconds over a few hours. Finally, future plans are discussed.

Near-Earth asteroids orbits using Gaia and ground-based observations

NASA Astrophysics Data System (ADS)

Bancelin, D.; Hestroffer, D.; Thuillot, W.

2011-05-01

Potentially Hazardous Asteroids (PHAs) are Near-Earth Asteroids caraterised by a Minimum Orbital Intersection Distance (MOID) with Earth less to 0.05 A.U and an absolute magnitude H<22. Those objects have sometimes a so significant close approach with Earth that they can be put on a chaotic orbit. This kind of orbit is very sensitive for exemple to the initial conditions, to the planetary theory used (for instance JPL's model versus IMCCE's model) or even to the numerical integrator used (Lie Series, Bulirsch-Stoer or Radau). New observations (optical, radar, flyby or satellite mission) can improve those orbits and reduce the uncertainties on the Keplerian elements.The Gaia mission is an astrometric mission that will be launched in 2012 and will observe a large number of Solar System Objects down to magnitude V≤20. During the 5-year mission, Gaia will continuously scan the sky with a specific strategy: objects will be observed from two lines of sight separated with a constant basic angle. Five constants already fixed determinate the nominal scanning law of Gaia: The inertial spin rate (1°/min) that describe the rotation of the spacecraft around an axis perpendicular to those of the two fields of view, the solar-aspect angle (45°) that is the angle between the Sun and the spacecraft rotation axis, the precession period (63.12 days) which is the precession of the spin axis around the Sun-Earth direction. Two other constants are still free parameters: the initial spin phase, and the initial precession angle that will be fixed at the start of the nominal science operations. These latter are constraint by scientific outcome (e.g. possibility of performing test of fundamental physics) together with operational requirements (downlink to Earth windows). Several sets of observations of specific NEOs will hence be provided according to the initial precession angle. The purpose here is to study the statistical impact of the initial precession angle on the error

Effect of observed micropolar motions on wave propagation in deep Earth minerals

NASA Astrophysics Data System (ADS)

Abreu, Rafael; Thomas, Christine; Durand, Stephanie

2018-03-01

We provide a method to compute the Cosserat couple modulus for a bridgmanite (MgSiO3 silicate perovskite) solid from frequency gaps observed in Raman experiments. To this aim, we apply micropolar theory which is a generalization of the classical linear elastic theory, where each particle has an intrinsic rotational degree of freedom, called micro-rotation and/or spin, and which depends on the so-called Cosserat couple modulus μc that characterizes the micropolar medium. We investigate both wave propagation and dispersion. The wave propagation simulations in both potassium nitrate (KNO3) and bridgmanite crystal leads to a faster elastic wave propagation as well as to an independent rotational field of motion, called optic mode, which is smaller in amplitude compared to the conventional rotational field. The dispersion analysis predicts that the optic mode only appears above a cutoff frequency, ωr , which has been observed in Raman experiments done at high pressures and temperatures on bridgmanite crystal. The comparison of the cutoff frequency observed in experiments and the micropolar theory enables us to compute for the first time the temperature and pressure dependency of the Cosserat couple modulus μc of bridgmanite. This study thus shows that the micropolar theory can explain particle motions observed in laboratory experiments that were before neglected and that can now be used to constrain the micropolar elastic constants of Earth's mantle like material. This pioneer work aims at encouraging the use of micropolar theory in future works on deep Earth's mantle material by providing Cosserat couple modulus that were not available before.

Properties of an Earth-like planet orbiting a Sun-like star: Earth observed by the EPOXI mission.

PubMed

Livengood, Timothy A; Deming, L Drake; A'hearn, Michael F; Charbonneau, David; Hewagama, Tilak; Lisse, Carey M; McFadden, Lucy A; Meadows, Victoria S; Robinson, Tyler D; Seager, Sara; Wellnitz, Dennis D

2011-11-01

NASA's EPOXI mission observed the disc-integrated Earth and Moon to test techniques for reconnoitering extrasolar terrestrial planets, using the Deep Impact flyby spacecraft to observe Earth at the beginning and end of Northern Hemisphere spring, 2008, from a range of ∼1/6 to 1/3 AU. These observations furnish high-precision and high-cadence empirical photometry and spectroscopy of Earth, suitable as "ground truth" for numerically simulating realistic observational scenarios for an Earth-like exoplanet with finite signal-to-noise ratio. Earth was observed at near-equatorial sub-spacecraft latitude on 18-19 March, 28-29 May, and 4-5 June (UT), in the range of 372-4540 nm wavelength with low visible resolving power (λ/Δλ=5-13) and moderate IR resolving power (λ/Δλ=215-730). Spectrophotometry in seven filters yields light curves at ∼372-948 nm filter-averaged wavelength, modulated by Earth's rotation with peak-to-peak amplitude of ≤20%. The spatially resolved Sun glint is a minor contributor to disc-integrated reflectance. Spectroscopy at 1100-4540 nm reveals gaseous water and carbon dioxide, with minor features of molecular oxygen, methane, and nitrous oxide. One-day changes in global cloud cover resulted in differences between the light curve beginning and end of ≤5%. The light curve of a lunar transit of Earth on 29 May is color-dependent due to the Moon's red spectrum partially occulting Earth's relatively blue spectrum. The "vegetation red edge" spectral contrast observed between two long-wavelength visible/near-IR bands is ambiguous, not clearly distinguishing between the verdant Earth diluted by cloud cover versus the desolate mineral regolith of the Moon. Spectrophotometry in at least one other comparison band at short wavelength is required to distinguish between Earth-like and Moon-like surfaces in reconnaissance observations. However, measurements at 850 nm alone, the high-reflectance side of the red edge, could be sufficient to

3D Orbit Visualization for Earth-Observing Missions

NASA Technical Reports Server (NTRS)

Jacob, Joseph C.; Plesea, Lucian; Chafin, Brian G.; Weiss, Barry H.

2011-01-01

This software visualizes orbit paths for the Orbiting Carbon Observatory (OCO), but was designed to be general and applicable to any Earth-observing mission. The software uses the Google Earth user interface to provide a visual mechanism to explore spacecraft orbit paths, ground footprint locations, and local cloud cover conditions. In addition, a drill-down capability allows for users to point and click on a particular observation frame to pop up ancillary information such as data product filenames and directory paths, latitude, longitude, time stamp, column-average dry air mole fraction of carbon dioxide, and solar zenith angle. This software can be integrated with the ground data system for any Earth-observing mission to automatically generate daily orbit path data products in Google Earth KML format. These KML data products can be directly loaded into the Google Earth application for interactive 3D visualization of the orbit paths for each mission day. Each time the application runs, the daily orbit paths are encapsulated in a KML file for each mission day since the last time the application ran. Alternatively, the daily KML for a specified mission day may be generated. The application automatically extracts the spacecraft position and ground footprint geometry as a function of time from a daily Level 1B data product created and archived by the mission s ground data system software. In addition, ancillary data, such as the column-averaged dry air mole fraction of carbon dioxide and solar zenith angle, are automatically extracted from a Level 2 mission data product. Zoom, pan, and rotate capability are provided through the standard Google Earth interface. Cloud cover is indicated with an image layer from the MODIS (Moderate Resolution Imaging Spectroradiometer) aboard the Aqua satellite, which is automatically retrieved from JPL s OnEarth Web service.

Trajectories of ballistic impact ejecta on a rotating Earth

NASA Technical Reports Server (NTRS)

Alvarez, W.

1994-01-01

On an airless, slowly rotating planetary body like the Moon, ejecta particles from an impact follow simple ballistic trajectories. If gaseous interactions in the fireball are ignored, ejecta particles follow elliptical orbits with the center of the planetary body at one focus until they encounter the surface at the point of reimpact. The partial elliptical orbit of the ejecta particle lies in a plane in inertial (galactic) coordinates. Because of the slow rotation rate (for example, 360 degrees/28 days for the Moon), the intersection of the orbital plane and the surface remains nearly a great circle during the flight time of the ejecta. For this reason, lunar rays, representing concentrations of ejecta with the same azimuth but different velocities and/or ejecta angles, lie essentially along great circles. Ejecta from airless but more rapidly rotating bodies will follow more complicated, curving trajectories when plotted in the coordinate frame of the rotating planet or viewed as rays on the planetary surface. The curvature of trajectories of ejecta particles can be treated as a manifestation of the Coriolis effect, with the particles being accelerated by Coriolis pseudoforces. However, it is more straightforward to calculate the elliptical orbit in inertial space and then determine how far the planet rotates beneath the orbiting ejecta particle before reimpact. The Earth's eastward rotation affects ballistic ejecta in two ways: (1) the eastward velocity component increases the velocity of eastbound ejecta and reduces the velocity of westbound ejecta; and (2) the Earth turns underneath inflight ejecta, so that although the latitude of reimpact is not changed, the longitude is displaced westward, with the displacement increasing as a function of the time the ejecta remains aloft.

Effects of Earth's rotation on the early differentiation of a terrestrial magma ocean

NASA Astrophysics Data System (ADS)

Maas, Christian; Hansen, Ulrich

2015-11-01

Similar to other terrestrial planets like Moon and Mars, Earth experienced a magma ocean period about 4.5 billion years ago. On Earth differentiation processes in the magma ocean set the initial conditions for core formation and mantle evolution. During the magma ocean period Earth was rotating significantly faster than today. Further, the viscosity of the magma was low, thus that planetary rotation potentially played an important role for differentiation. However, nearly all previous studies neglect rotational effects. All in all, our results suggest that planetary rotation plays an important role for magma ocean crystallization. We employ a 3-D numerical model to study crystal settling in a rotating and vigorously convecting early magma ocean. We show that crystal settling in a terrestrial magma ocean is crucially affected by latitude as well as by rotational strength and crystal density. Due to rotation an inhomogeneous accumulation of crystals during magma ocean solidification with a distinct crystal settling between pole and equator could occur. One could speculate that this may have potentially strong effects on the magma ocean solidification time and the early mantle composition. It could support the development of a basal magma ocean and the formation of anomalies at the core-mantle boundary in the equatorial region, reaching back to the time of magma ocean solidification.

Effects of dynamic long-period ocean tides on changes in earth's rotation rate

NASA Technical Reports Server (NTRS)

Nam, Young; Dickman, S. R.

1990-01-01

As a generalization of the zonal response coefficient first introduced by Agnew and Farrell (1978), the zonal response function kappa of the solid earth-ocean system is defined as the ratio, in the frequency domain, of the tidal change in earth's rotation rate to the tide-generating potential. Amplitudes and phases of kappa for the monthly, fortnightly, and nine-day lunar tides are estimated from 2 1/2 years of VLBI UT1 observations, corrected for atmospheric angular momentum effects using NMC wind and pressure series. Using the dynamic ocean tide model of Dickman (1988, 1989), amplitudes and phases of kappa for an elastic earth-ocean system are predicted. The predictions confirm earlier results which found that dynamic effects of the longer-period ocean tides reduce the amplitude of kappa by about 1 percent.

Earth Glint Observations Conducted During the Deep Impact Spacecraft Flyby

NASA Technical Reports Server (NTRS)

Barry, R. K.; Deming, L. D.; Robinson, T.; Hewagama, T.

2010-01-01

We describe observations of Earth conducted using the High Resolution Instrument (HRI) - a 0.3 m f/35 telescope - on the Deep Impact (DI) spacecraft during its recent flybys. Earth was observed on five occasions: 2008-Mar-18 18:18 UT, 2008-May-28 20:05 UT, 2008-Jun-4 16:57 UT, 2009-Mar-27 16:19 and 2009-Oct-4 09:37 UT. Each set of observations was conducted over a full 24-hour rotation of Earth and a total of thirteen NIR spectra were taken on two-hour intervals during each observing period. Photometry in the 450, SSO, 650 and 8S0 nm filters was taken every fifteen minutes and every hour for the 350, 750 and 950 nm filters. The spacecraft was located over the equator for the three sets of observations in 2008, while the 2009- Mar and 2009-Oct were taken over the north and south Polar Regions, respectively. Observations of calibrator stars Canopus and Achernar were conducted on multiple occasions through all filters. The observations detected a strong specular glint not necessarily associated with a body of water. We describe spectroscopic characterization of the glint and evidence for the possibility of detection of reflection from high cirrus clouds. We describe implications for observations of extrasolar planets.

Effect of the Earth's rotation on subduction processes

NASA Astrophysics Data System (ADS)

Levin, B. W.; Rodkin, M. V.; Sasorova, E. V.

2017-09-01

The role played by the Earth's rotation is very important in problems of physics of the atmosphere and ocean. The importance of inertia forces is traditionally estimated by the value of the Rossby number: if this parameter is small, the Coriolis force considerably affects the character of movements. In the case of convection in the Earth's mantle and movements of lithospheric plates, the Rossby number is quite small; therefore, the effect of the Coriolis force is reflected in the character of movements of the lithospheric plates. Analysis of statistical data on subduction zones verifies this suggestion.

VizieR Online Data Catalog: SMART97, rigid Earth rotation new solution (Bretagnon+ 1998)

NASA Astrophysics Data System (ADS)

Bretagnon, P.; Francou, G.; Rocher, P.; Simon, J. L.

1998-03-01

The Earth rotation solution SMART97 (Solution du Mouvement de l'Axe de Rotation de la Terre) is an analytical solution of the Earth rotation in the rigid case. It gives the expressions of precession-nutation and rotation of the Earth for the 3 Euler angles ψ, ω, φ as well as for the quantities p, ɛ, χ, and the sidereal time. For the axis of figure (fig), these 7 quantities are given in the dynamical system (dyn) and in the kinematical system (kin). SMART97 also gives the variables ψ and ω, in the dynamical system, for the differences (axis of figure - axis of rotation) (rot) and (axis of figure - axis of the angular momentum) (ang). The accuracy of the solution is better than 2.2 microarcseconds for all these variables over 20000 days, between 1968 and 2023. A program EXAMPLE (Fortran 77) is provided which makes use of the subroutine SMART97 which substitutes the time in the series of the solutions SMART97. (18 data files).

Determining the Ocean's Role on the Variable Gravity Field and Earth Rotation

NASA Technical Reports Server (NTRS)

Ponte, Rui M.; Frey, H. (Technical Monitor)

2000-01-01

A number of ocean models of different complexity have been used to study changes in the oceanic angular momentum (OAM) and mass fields and their relation to the variable Earth rotation and gravity field. Time scales examined range from seasonal to a few days. Results point to the importance of oceanic signals in driving polar motion, in particular the Chandler and annual wobbles. Results also show that oceanic signals have a measurable impact on length-of-day variations. Various circulation features and associated mass signals, including the North Pacific subtropical gyre, the equatorial currents, and the Antarctic Circumpolar Current play a significant role in oceanic angular momentum variability. The impact on OAM values of an optimization procedure that uses available data to constrain ocean model results was also tested for the first time. The optimization procedure yielded substantial changes, in OAM, related to adjustments in both motion and mass fields,as well as in the wind stress torques acting on the ocean. Constrained OAM values were found to yield noticeable improvements in the agreement with the observed Earth rotation parameters, particularly at the seasonal timescale.

Foucault and the rotation of the Earth

NASA Astrophysics Data System (ADS)

Sommeria, Joël

2017-11-01

In February 1851, Léon Foucault published in the Comptes rendus his famous pendulum experiment performed at the "Observatoire de Paris". This ended two centuries of quest for an experimental demonstration of Earth rotation. One month later, the experiment was reproduced at larger scale in the Panthéon and, as early as the summer of 1851, it was being repeated in many places across the world. The next year, Foucault invented the gyroscope to get a still more direct proof of Earth rotation. The theory relied on the masterpiece treatise of Laplace on celestial mechanics, published in 1805, which already contained the mathematical expression of the force that would be discovered by Gustave Coriolis 30 years later. The idea of a fictitious inertial force proposed by Coriolis prevailed by the end of 19th century, as it was conceptually simpler than Laplace's approach. The full theory of the Foucault pendulum, taking into account its unavoidable imperfections, was not obtained until three decades later by Kamerlingh Onnes, the future discoverer of liquid helium and superconductivity. Today, Foucault's exceptional creativity is still a source of inspiration for research and the promotion of science through experimental proofs widely available to the public.

Earth Observations

NASA Image and Video Library

2010-06-16

ISS024-E-006136 (16 June 2010) --- Polar mesospheric clouds, illuminated by an orbital sunrise, are featured in this image photographed by an Expedition 24 crew member on the International Space Station. Polar mesospheric, or noctilucent (?night shining?), clouds are observed from both Earth?s surface and in orbit by crew members aboard the space station. They are called night-shining clouds as they are usually seen at twilight. Following the setting of the sun below the horizon and darkening of Earth?s surface, these high clouds are still briefly illuminated by sunlight. Occasionally the ISS orbital track becomes nearly parallel to Earth?s day/night terminator for a time, allowing polar mesospheric clouds to be visible to the crew at times other than the usual twilight due to the space station altitude. This unusual photograph shows polar mesospheric clouds illuminated by the rising, rather than setting, sun at center right. Low clouds on the horizon appear yellow and orange, while higher clouds and aerosols are illuminated a brilliant white. Polar mesospheric clouds appear as light blue ribbons extending across the top of the image. These clouds typically occur at high latitudes of both the Northern and Southern Hemispheres, and at fairly high altitudes of 76?85 kilometers (near the boundary between the mesosphere and thermosphere atmospheric layers). The ISS was located over the Greek island of Kos in the Aegean Sea (near the southwestern coastline of Turkey) when the image was taken at approximately midnight local time. The orbital complex was tracking northeastward, nearly parallel to the terminator, making it possible to observe an apparent ?sunrise? located almost due north. A similar unusual alignment of the ISS orbit track, terminator position, and seasonal position of Earth?s orbit around the sun allowed for striking imagery of polar mesospheric clouds over the Southern Hemisphere earlier this year.

Estimating the Earth's geometry, rotation and gravity field using a multi-satellite SLR solution

NASA Astrophysics Data System (ADS)

Stefka, V.; Blossfeld, M.; Mueller, H.; Gerstl, M.; Panafidina, N.

2012-12-01

Satellite Laser Ranging (SLR) is the unique technique to determine station coordinates, Earth Orientation Parameter (EOP) and Stokes coefficients of the Earth's gravity field in one common adjustment. These parameters form the so called "three pillars" (Plag & Pearlman, 2009) of the Global Geodetic Observing System (GGOS). In its function as official analysis center of the International Laser Ranging Service (ILRS), DGFI is developing and maintaining software to process SLR observations called "DGFI Orbit and Geodetic parameter estimation Software" (DOGS). The software is used to analyze SLR observations and to compute multi-satellite solutions. To take benefit of different orbit performances (e.g. inclination and altitude), a solution using ten different spherical satellites (ETALON1/2, LAGEOS1/2, STELLA, STARLETTE, AJISAI, LARETS, LARES, BLITS) covering the period of 12 years of observations is computed. The satellites are relatively weighted using a variance component estimation (VCE). The obtained weights are analyzed w.r.t. the potential of the satellite to monitor changes in the Earths geometry, rotation and gravity field. The estimated parameters (station coordinates and EOP) are validated w.r.t. official time series of the IERS. The Stokes coefficients are compared to recent gravity field solutions.

Manifestations of the rotation and gravity of the Earth in high-energy physics experiments

NASA Astrophysics Data System (ADS)

Obukhov, Yuri N.; Silenko, Alexander J.; Teryaev, Oleg V.

2016-08-01

The inertial (due to rotation) and gravitational fields of the Earth affect the motion of an elementary particle and its spin dynamics. This influence is not negligible and should be taken into account in high-energy physics experiments. Earth's influence is manifest in perturbations in the particle motion, in an additional precession of the spin, and in a change of the constitutive tensor of the Maxwell electrodynamics. Bigger corrections are oscillatory, and their contributions average to zero. Other corrections due to the inhomogeneity of the inertial field are not oscillatory but they are very small and may be important only for the storage ring electric dipole moment experiments. Earth's gravity causes the Newton-like force, the reaction force provided by a focusing system, and additional torques acting on the spin. However, there are no observable indications of the electromagnetic effects due to Earth's gravity.

The Group on Earth Observations and the Global Earth Observation System of Systems

NASA Astrophysics Data System (ADS)

Achache, J.

2006-05-01

The Group on Earth Observations (GEO) is leading a worldwide effort to build a Global Earth Observation System of Systems (GEOSS) over the next 10 years. The GEOSS vision, articulated in its 10-Year Implementation Plan, represents the consolidation of a global scientific and political consensus: the assessment of the state of the Earth requires continuous and coordinated observation of our planet at all scales. GEOSS aims to achieve comprehensive, coordinated and sustained observations of the Earth system in order to improve monitoring of the state of the Earth; increase understanding of Earth processes; and enhance prediction of the behaviour of the Earth system. After the World Summit on Sustainable Development in 2002 highlighted the urgent need for coordinated observations relating to the state of the Earth, GEO was established at the Third Earth Observation Summit in February 2005 and the GEOSS 10-Year Implementation Plan was endorsed. GEO currently involves 60 countries; the European Commission; and 43 international organizations and has begun implementation of the GEOSS 10-Year Implementation Plan. GEO programme activities cover nine societal benefit areas (Disasters; Health; Energy; Climate; Water; Weather; Ecosystems; Agriculture; Biodiversity) and five transverse or crosscutting elements (User Engagement; Architecture; Data Management; Capacity Building; Outreach). All these activities have as their final goal the establishment of the "system of systems" which will yield a broad range of basic societal benefits, including the reduction of loss of life and property from tsunamis, hurricanes, and other natural disasters; improved water resource and energy management; and improved understanding of environmental factors significant to public health. As a "system of systems", GEOSS will work with and build upon existing national, regional, and international systems to provide comprehensive, coordinated Earth observations from thousands of instruments worldwide

DSCOVR: A New Perspective for Earth Observations from Space. Synergism and Complementarity with Existing Platforms

NASA Astrophysics Data System (ADS)

Valero, F. P.

2011-12-01

The Sun-Earth Lagrange points L-1 and L-2 mark positions where the gravitational pull of the Earth and Sun precisely equals the centripetal force required to rotate with the Earth about the Sun with the same orbital period as the Earth. Therefore, a satellite maintained at one of these Lagrange points would keep the same relative position to the Sun and the Earth and be able to observe most points on the planet as the Earth rotates during the day. L-1 and L-2 are of particular interest because a satellite at either location can easily be maintained near the Sun-Earth line and views the entire daytime hemisphere from L-1 and the entire nighttime hemisphere from L-2. Since L-1 and L-2 are in the ecliptic plane, synoptic, high temporal-resolution observations would be obtained as every point on the planet, including both polar regions, transits from sunrise to sunset (L-1) or from sunset to sunrise (L-2). In summary, a pair of deep-space observatories, one at L-1 (daytime) and one at L-2 (nighttime), could acquire minute by minute climate quality data for essentially every point on Earth, all observations simultaneously for the whole planet. Such unique attributes are incorporated in the Deep Space Climate Observatory (DSCOVR) that will systematically observe climate drivers (radiation, aerosols, ozone, clouds, oxygen A-band) from L-1 in ways not possible but synergistically complementary with platforms in Low Earth Orbit (LEO) or Geostationary Earth Orbit (GEO). The combination of Solar Lagrange Points (located in the ecliptic plane) GEO (located in the equatorial plane) and LEO platforms would certainly provide a powerful observational tool as well as enriched data sets for Earth sciences. Such synergism is greatly enhanced when one considers the potential of utilizing LEO, GEO, and Lagrange point satellites as components of an integrated observational system. For example, satellites at L-1 and L-2 will view the Earth plus the Moon while simultaneously having in

Earth rotation and ENSO events: combined excitation of interannual LOD variations by multiscale atmospheric oscillations

NASA Astrophysics Data System (ADS)

Zheng, Dawei; Ding, Xiaoli; Zhou, Yonghong; Chen, Yongqi

2003-03-01

Time series of the length of day characterizing the rate of Earth rotation, the atmospheric angular momentum and the Southern Oscillation Index from 1962 to 2000 are used to reexamine the relationships between the ENSO events and the changes in the length of day, as well as the global atmospheric angular momentum. Particular attention is given to the different effects of the 1982-1983 and 1997-1998 ENSO events on the variations of Earth rotation. The combined effects of multiscale atmospheric oscillations (seasonal, quasi-biennial and ENSO time scales) on the anomalous variations of the interannual rates of Earth rotation are revealed in this paper by studying the wavelet spectra of the data series.

Overview of Japanese Earth observation programs

NASA Astrophysics Data System (ADS)

Shimoda, Haruhisa; Honda, Yoshiaki

2017-09-01

Five programs, i.e. ASTER, GOSAT, GCOM-W1, GPM and ALOS-2 are going on in Japanese Earth Observation programs. ASTER has lost its short wave infrared channels. AMSR-E stopped its operation, but it started its operation from Sep. 2012 with slow rotation speed. It finally stopped on December 2015. GCOM-W1 was launched on 18, May, 2012 and is operating well as well as GOSAT. ALOS (Advanced Land Observing Satellite) was successfully launched on 24th Jan. 2006. ALOS carries three instruments, i.e., PRISM (Panchromatic Remote Sensing Instrument for Stereo Mapping), AVNIR-2 (Advanced Visible and Near Infrared Radiometer), and PALSAR (Phased Array L band Synthetic Aperture Radar). Unfortunately, ALOS has stopped its operation on 22nd, April, 2011 by power loss. GOSAT (Greenhouse Gas Observation Satellite) was successfully launched on 29, January, 2009. GOSAT carries 2 instruments, i.e. a green house gas sensor (TANSO-FTS) and a cloud/aerosol imager (TANSO-CAI). The main sensor is a Fourier transform spectrometer (FTS) and covers 0.76 to 15 μm region with 0.2 to 0.5 cm-1 resolution. SMILES (Superconducting Millimeter wave Emission Spectrometer) was launched on September 2009 to ISS and started the observation, but stopped its operation on April 2010. GPM (Global Precipitation Mission) core satellite was launched on Feb. 2014. GPM is a joint project with NASA and carries two instruments. JAXA has developed DPR (Dual frequency Precipitation Radar) which is a follow on of PR on TRMM. ALOS F/O satellites are divided into two satellites, i.e. SAR and optical satellites. The first one of ALOS F/O is called ALOS 2 and carries L-band SAR. It was launched on May 2014. JAXA is planning to launch follow on of optical sensors. It is now called Advanced Optical Satellite and the planned launch date is fiscal 2019. Other future satellites are GCOM-C1 (ADEOS-2 follow on), GOSAT-2 and EarthCare. GCOM-C1 will be launched on 2017 and GOSAT-2 will be launched on fiscal 2018. Another project

The Goal of the IAU/IAG Joint Working Group on the Theory of Earth Rotation

NASA Technical Reports Server (NTRS)

Ferrandiz, J. M.; Gross, R. S.

2013-01-01

In 2012 the International Association of Geodesy (IAG) and the International Astronomical Union (IAU) initiated a process to establish a Joint Working Group (JWG) on theory of Earth rotation with the purpose of promoting the development of improved theories of the Earth rotation which reach the accuracy required to meet the needs of the near future as recommended by, e.g. GGOS, the Global Geodetic Observing System of the IAG. The JWG was approved by both organizations in April 2013 with the chairs being the two authors of this paper. Its structure comprises three Sub Working Groups (SWGs) addressing Precession/Nutation, Polar Motion and UT1, the Numerical Solutions and Validation, respectively. The SWGs should work in parallel for the sake of efficiency, but should keep consistency as an overall goal. This paper offers a view of the objectives and scope of the JWG and reports about its initial activities and plans.

Dynamics of rotationally fissioned asteroids: Source of observed small asteroid systems

NASA Astrophysics Data System (ADS)

Jacobson, Seth A.; Scheeres, Daniel J.

2011-07-01

We present a model of near-Earth asteroid (NEA) rotational fission and ensuing dynamics that describes the creation of synchronous binaries and all other observed NEA systems including: doubly synchronous binaries, high- e binaries, ternary systems, and contact binaries. Our model only presupposes the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect, "rubble pile" asteroid geophysics, and gravitational interactions. The YORP effect torques a "rubble pile" asteroid until the asteroid reaches its fission spin limit and the components enter orbit about each other (Scheeres, D.J. [2007]. Icarus 189, 370-385). Non-spherical gravitational potentials couple the spin states to the orbit state and chaotically drive the system towards the observed asteroid classes along two evolutionary tracks primarily distinguished by mass ratio. Related to this is a new binary process termed secondary fission - the secondary asteroid of the binary system is rotationally accelerated via gravitational torques until it fissions, thus creating a chaotic ternary system. The initially chaotic binary can be stabilized to create a synchronous binary by components of the fissioned secondary asteroid impacting the primary asteroid, solar gravitational perturbations, and mutual body tides. These results emphasize the importance of the initial component size distribution and configuration within the parent asteroid. NEAs may go through multiple binary cycles and many YORP-induced rotational fissions during their approximately 10 Myr lifetime in the inner Solar System. Rotational fission and the ensuing dynamics are responsible for all NEA systems including the most commonly observed synchronous binaries.

Co-Seismic Energy Changes Induced by Earthquakes on a Rotating, Gravitating Earth

NASA Technical Reports Server (NTRS)

Chao, Benjamin F.; Gross, Richard S.

2003-01-01

Besides operating its own energy budget, an earthquake acts as an agent transferring a much greater amount of energy among the Earth's rotation, elastic field, gravitational field and internal heat. We compute the co-seismic, globally integrated gravitational and rotation changes induced by some 20,000 large earthquakes that occurred in the last quarter century, according to Chao et al. (1995, GJI, 122,776- 783,784-789) and using the Harvard CMT catalog. The result confirms an extremely strong tendency for the earthquakes to decrease the global gravitational energy and to increase the spin energy. It is found that energy is being extracted from the Earth's gravitational field by the action of earthquakes at an average rate of about approx. 2 TeraW during the studied period, larger by far than the approx. 7 GigaW for the average rate of the earthquake-induced rotational energy increase and the approx. 5 GigaW for the seismic energy release. Based on energetics considerations and assuming the inability of the Earth to build up elastic energy continuously over time, it is argued that earthquakes, by converting gravitational energy, may make a significant contribution to the global hedflow.

Nystagmus responses in a group of normal humans during earth-horizontal axis rotation

NASA Technical Reports Server (NTRS)

Wall, Conrad, III; Furman, Joseph M. R.

1989-01-01

Horizontal eye movement responses to earth-horizontal yaw axis rotation were evaluated in 50 normal human subjects who were uniformly distributed in age (20-69 years) and each age group was then divided by gender. Subjects were rotated with eyes open in the dark, using clockwise and counter-clockwise 60 deg velocity trapezoids. The nystagmus slow component velocity is analyzed. It is shown that, despite large intersubject variability, parameters which describe earth-horizontal yaw axis responses are loosely interrelated, and some of them vary significantly with gender and age.

Gravitomagnetic Field of the Universe and Coriolis Force on the Rotating Earth

ERIC Educational Resources Information Center

Veto, B.

2011-01-01

The Machian effect of distant masses of the universe in the frame of reference of the rotating Earth is demonstrated using the gravitomagnetic approach of general relativity. This effect appears in the form of a gravitomagnetic Lorentz force acting on moving bodies on the Earth. The gravitomagnetic field of the universe--deduced from a simple…

The Unruh effect for eccentric uniformly rotating observers

NASA Astrophysics Data System (ADS)

Ramezani-Aval, H.

It is common to use Galilean rotational transformation (GRT) to investigate the Unruh effect for uniformly rotating observers. However, the rotating observer in this subject is an eccentric observer while GRT is only valid for centrally rotating observers. Thus, the reliability of the results of applying GRT to the study of the Unruh effect might be considered as questionable. In this work, the rotational analog of the Unruh effect is investigated by employing two relativistic rotational transformations corresponding to the eccentric rotating observer, and it is shown that in both cases, the detector response function is nonzero. It is also shown that although consecutive Lorentz transformations cannot give a frame within which the canonical construction can be carried out, the expectation value of particle number operator in canonical approach will be zero if we use modified Franklin transformation. These conclusions reinforce the claim that correspondence between vacuum states defined via canonical field theory and a detector is broken for rotating observers. Some previous conclusions are commented on and some controversies are also discussed.

Earth Observation

NASA Image and Video Library

2013-08-20

Earth observation taken during day pass by an Expedition 36 crew member on board the International Space Station (ISS). Per Twitter message: Looking southwest over northern Africa. Libya, Algeria, Niger.

The Rotational and Gravitational Effect of Earthquakes

NASA Technical Reports Server (NTRS)

Gross, Richard

2000-01-01

The static displacement field generated by an earthquake has the effect of rearranging the Earth's mass distribution and will consequently cause the Earth's rotation and gravitational field to change. Although the coseismic effect of earthquakes on the Earth's rotation and gravitational field have been modeled in the past, no unambiguous observations of this effect have yet been made. However, the Gravity Recovery And Climate Experiment (GRACE) satellite, which is scheduled to be launched in 2001, will measure time variations of the Earth's gravitational field to high degree and order with unprecedented accuracy. In this presentation, the modeled coseismic effect of earthquakes upon the Earth's gravitational field to degree and order 100 will be computed and compared to the expected accuracy of the GRACE measurements. In addition, the modeled second degree changes, corresponding to changes in the Earth's rotation, will be compared to length-of-day and polar motion excitation observations.

Measurement of the Earth's rotation: 720 BC to AD 2015

NASA Astrophysics Data System (ADS)

Stephenson, F. R.; Morrison, L. V.; Hohenkerk, C. Y.

2016-12-01

New compilations of records of ancient and medieval eclipses in the period 720 BC to AD 1600, and of lunar occultations of stars in AD 1600-2015, are analysed to investigate variations in the Earth's rate of rotation. It is found that the rate of rotation departs from uniformity, such that the change in the length of the mean solar day (lod) increases at an average rate of +1.8 ms per century. This is significantly less than the rate predicted on the basis of tidal friction, which is +2.3 ms per century. Besides this linear change in the lod, there are fluctuations about this trend on time scales of decades to centuries. A power spectral density analysis of fluctuations in the range 2-30 years follows a power law with exponent -1.3, and there is evidence of increased power at a period of 6 years. There is some indication of an oscillation in the lod with a period of roughly 1500 years. Our measurements of the Earth's rotation for the period 720 BC to AD 2015 set firm boundaries for future work on post-glacial rebound and core-mantle coupling which are invoked to explain the departures from tidal friction.

Determining the Ocean's Role on the Variable Gravity Field and Earth Rotation

NASA Technical Reports Server (NTRS)

Ponte, Rui M.

2000-01-01

Our three year investigation, carried out over the period 18-19 Nov 2000, focused on the study of the variability in ocean angular momentum and mass signals and their relation to the Earth's variable rotation and gravity field. This final report includes a summary description of our work and a list of related publications and presentations. One thrust of the investigation was to determine and interpret the changes in the ocean mass field, as they impact on the variable gravity field and Earth rotation. In this regard, the seasonal cycle in local vertically-integrated ocean mass was analyzed using two ocean models of different complexity: (1) the simple constant-density, coarse resolution model of Ponte; and (2) the fully stratified, eddy-resolving model of Semtner and Chervin. The dynamics and thermodynamics of the seasonal variability in ocean mass were examined in detail, as well as the methodologies to calculate those changes under different model formulations. Another thrust of the investigation was to examine signals in ocean angular momentum (OAM) in relation to Earth rotation changes. A number of efforts were undertaken in this regard. Sensitivity of the oceanic excitation to different assumptions about how the ocean is forced and how it dissipates its energy was explored.

Rotational seismology

USGS Publications Warehouse

Lee, William H K.

2016-01-01

Rotational seismology is an emerging study of all aspects of rotational motions induced by earthquakes, explosions, and ambient vibrations. It is of interest to several disciplines, including seismology, earthquake engineering, geodesy, and earth-based detection of Einstein’s gravitation waves.Rotational effects of seismic waves, together with rotations caused by soil–structure interaction, have been observed for centuries (e.g., rotated chimneys, monuments, and tombstones). Figure 1a shows the rotated monument to George Inglis observed after the 1897 Great Shillong earthquake. This monument had the form of an obelisk rising over 19 metres high from a 4 metre base. During the earthquake, the top part broke off and the remnant of some 6 metres rotated about 15° relative to the base. The study of rotational seismology began only recently when sensitive rotational sensors became available due to advances in aeronautical and astronomical instrumentations.

(abstract) Effect of Long Period Ocean Tides on the Earth's Rotation

NASA Technical Reports Server (NTRS)

Gross, R. S.; Chao, B. F.; Desai, S.

1996-01-01

The second-degree zonal tide raising potential, which is responsible for tidal changes in the Earth's rotation rate and length-of-day, is symmetric about the polar axis and hence can excite the Earth's polar motion only through its action upon nonaxisymmetric features of the Earth such as the oceans. Ocean tidal excitation of polar motion in the diurnal and semidiurnal tidal bands has been previously detected and extensively examined. Here, the detection of ocean tidal excitation of polar motion in the long-period tidal band, specifically at the Mf' (13.63-day) and Mf (13.66-day) tidal frequencies, is reported.

Earth Observation

NASA Image and Video Library

2011-08-02

ISS028-E-020276 (2 Aug. 2011) --- This photograph of polar mesospheric clouds was acquired at an altitude of just over 202 nautical miles (about 322 kilometers) in the evening hours (03:19:54 Greenwich Mean Time) on Aug. 2, 2011, as the International Space Station was passing over the English Channel. The nadir coordinates of the station were 49.1 degrees north latitude and 5.5 degrees west longitude. Polar mesospheric clouds (also known as noctilucent, or ?night-shining? clouds) are transient, upper atmospheric phenomena that are usually observed in the summer months at high latitudes (greater than 50 degrees) of both the Northern and Southern Hemispheres. They appear bright and cloudlike while in deep twilight. They are illuminated by sunlight when the lower layers of the atmosphere are in the darkness of Earth?s shadow. The horizon of Earth appears at the bottom of the image, with some layers of the lower atmosphere already illuminated by the rising sun. The higher, bluish-colored clouds look much like wispy cirrus clouds, which can be found as high as 60,000 feet (18 kilometers) in the atmosphere. However noctilucent clouds, as seen here, are observed in the mesosphere at altitudes of 250,000 to 280,000 feet (about 76 to 85 kilometers). Astronaut observations of polar mesospheric clouds over northern Europe in the summer are not uncommon.

Earth Observation

NASA Image and Video Library

2013-08-03

Earth observation taken during day pass by an Expedition 36 crew member on board the International Space Station (ISS). Per Twitter message: Perhaps a dandelion losing its seeds in the wind? Love clouds!

Changes in the earth's rotation by tectonic movements

NASA Astrophysics Data System (ADS)

Vermeersen, L. L. A.; Vlaar, N. J.

1993-01-01

We propose that lithospheric processes unrelated to postglacial rebound and taking place under nonisostatic conditions are able to induce nonnegligible influences on the earth's rotation. Examples of such processes are mountain building and erosion, foundering flexure of oceanic basins and lithospheric snapbacking resulting from detachment of subducting slabs. Lithospheric and crustal rheologies and intraplate stresses are the dominant factors in these mechanisms, contrary to the mantle rheologies which are assumed to dominate the process of postglacial rebound.

Lagrange Point Missions: the Key to Next-Generation Integrated Earth Observations. DSCOVR Innovation

NASA Astrophysics Data System (ADS)

Valero, F. P. J.

2016-12-01

From L-1 DSCOVR is capable of new, unique observations potentially conducive to a deeper scientific understanding of the Earth sciences. At L-1 and L-2 the net gravitational pull of the Earth and Sun equals the centripetal force required to orbit the Sun with the same period as the Earth. Satellites at or near L-1 and L-2 keep the same position relative to the Sun and the Earth. DSCOVR does not orbit the Earth but the Sun in synchronism with Earth, acts like a planetoid (orbits the Sun in the ecliptic plane) while acquiring integrated plus spatially and time resolved scientific data as Earth rotates around its axis. Because of the planet's axial tilt relative to the ecliptic plane, the Polar Regions are visible during local summer from L-1 and local winter from L-2 (Fig. 1). DSCOVR's synoptic and continuous observations solve most of the temporal and spatial limitations associated with low Earth (LEO) and Geostationary (GEO) orbits. Two observatories, one at L-1 (daytime) and one at L-2 (nighttime), would acquire minute-by-minute climate quality data for essentially every point on Earth. The integration of L-1, L-2, LEO, and GEO satellites plus the Moon offers new scientific tools and enriched data sets for Earth sciences. Lagrange points observatories are key to next-generation integrated Earth observations. For example, DSCOVR at L-1 views the Earth plus the Moon (a reference) and simultaneously, at one time or another, all LEO and GEO satellites. The L-1 and L-2 satellites would be the link between the Moon, LEO and GEO satellites while providing the data needed to build an integrated Earth observational system. The above properties are the bases for DSCOVR's innovation and scientific approach that systematically observes climate drivers (radiation, aerosols, ozone, clouds, water vapor, vegetation) from L-1 in a way not possible but synergistic with other satellites. Next step: more capable L-1 plus L-2 satellites. The way of the future.

Earth Observation

NASA Image and Video Library

2014-06-27

Earth Observation taken during a day pass by the Expedition 40 crew aboard the International Space Station (ISS). Part of Space Station Remote Manipulator System (SSRMS) is visible. Folder lists this as: the Middle East, Israel.

Radar Observations of Near-Earth Asteroids 2000 UG11 and 2000 UK11

NASA Technical Reports Server (NTRS)

Nolan, M. C.; Margot, J.-L.; Howell, E. S.; Benner, L. A. M.; Ostro, S. J.; Jurgens, R. F.; Giorgini, J. D.; Campbell, D. B.

2001-01-01

Two small near-Earth asteroids, 2000 UG11 and 2000 UK11 were observed using the Arecibo and Goldstone radars a week after their discovery. 2000 UK11 is a rapidly rotating (3 min) approximately 30 m solid body. 2000 UG11 is two bodies separated by at least 300 m Additional information is contained in the original extended abstract..

Earth Observation

NASA Image and Video Library

2014-09-01

Earth Observation taken during a night pass by the Expedition 40 crew aboard the International Space Station (ISS). Folder lists this as: New Zealand Aurora night pass. On crewmember's Flickr page - Look straight down into an aurora.

Earth Observation

NASA Image and Video Library

2014-06-12

Earth Observation taken during a day pass by the Expedition 40 crew aboard the International Space Station (ISS). Folder lists this as: Moon, Japan, Kamchatka with a wild cloud. Part of a solar array is also visible.

CARMENES input catalogue of M dwarfs. III. Rotation and activity from high-resolution spectroscopic observations

NASA Astrophysics Data System (ADS)

Jeffers, S. V.; Schöfer, P.; Lamert, A.; Reiners, A.; Montes, D.; Caballero, J. A.; Cortés-Contreras, M.; Marvin, C. J.; Passegger, V. M.; Zechmeister, M.; Quirrenbach, A.; Alonso-Floriano, F. J.; Amado, P. J.; Bauer, F. F.; Casal, E.; Alonso, E. Diez; Herrero, E.; Morales, J. C.; Mundt, R.; Ribas, I.; Sarmiento, L. F.

2018-06-01

CARMENES is a spectrograph for radial velocity surveys of M dwarfs with the aim of detecting Earth-mass planets orbiting in the habitable zones of their host stars. To ensure an optimal use of the CARMENES guaranteed time observations, in this paper we investigate the correlation of activity and rotation for approximately 2200 M dwarfs, ranging in spectral type from M0.0 V to M9.0 V. We present new high-resolution spectroscopic observations with FEROS, CAFE, and HRS of approximately 500 M dwarfs. For each new observation, we determined its radial velocity and measured its Hα activity index and its rotation velocity. Additionally, we have multiple observations of many stars to investigate if there are any radial velocity variations due to multiplicity. The results of our survey confirm that early-M dwarfs are Hα inactive with low rotational velocities and that late-M dwarfs are Hα active with very high rotational velocities. The results of this high-resolution analysis comprise the most extensive catalogue of rotation and activity in M dwarfs currently available. Based on observations made at the Calar Alto Observatory, Spain, the European Southern Observatory, La Silla, Chile and McDonald Observatory, USA.Tables A.1-A.3 are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/614/A76

Earth Observation

NASA Image and Video Library

2013-07-26

Earth observation taken during day pass by an Expedition 36 crew member on board the International Space Station (ISS). Per Twitter message: Never tire of finding shapes in the clouds! These look very botanical to me. Simply perfect.

Correction to “Changes in the Earth's rotation by tectonic movements”

NASA Astrophysics Data System (ADS)

Vermeersen, L. L. A.; Vlaar, N. J.

1993-06-01

Present-day true polar wander and the secular non-tidal acceleration of the earth are usually attributed to post-glacial rebound. In the models which relate this rebound to changes in rotation, the mantle is assumed to relax passively to the melted ice-loads. The lithosphere is usually modeled as a highly viscous upper layer in these models, having viscosities which exceed mantle viscosities by several orders of magnitude. We propose that lithospheric processes unrelated to post-glacial rebound and taking place under non-isostatic conditions are also able to induce non-negligible influences on the earth's rotation. Examples of such processes are mountain building and erosion, foundering flexure of oceanic basins and lithospheric snapbacking resulting from detachment of subducting slabs. Lithospheric and crustal rheologies and intraplate-stresses are the dominant factors in these mechanisms, contrary to the mantle rheologies which are assumed to dominate the process of post-glacial rebound.

Earth as an Extrasolar Planet: Earth Model Validation Using EPOXI Earth Observations

NASA Technical Reports Server (NTRS)

Robinson, Tyler D.; Meadows, Victoria S.; Crisp, David; Deming, Drake; A'Hearn, Michael F.; Charbonneau, David; Livengood, Timothy A.; Seager, Sara; Barry, Richard; Hearty, Thomas;

Earth as an Extrasolar Planet: Earth Model Validation Using EPOXI Earth Observations

NASA Astrophysics Data System (ADS)

Robinson, Tyler D.; Meadows, Victoria S.; Crisp, David; Deming, Drake; A'Hearn, Michael F.; Charbonneau, David; Livengood, Timothy A.; Seager, Sara; Barry, Richard K.; Hearty, Thomas; Hewagama, Tilak; Lisse, Carey M.; McFadden, Lucy A.; Wellnitz, Dennis D.

2011-06-01

The EPOXI Discovery Mission of Opportunity reused the Deep Impact flyby spacecraft to obtain spatially and temporally resolved visible photometric and moderate resolution near-infrared (NIR) spectroscopic observations of Earth. These remote observations provide a rigorous validation of whole-disk Earth model simulations used to better understand remotely detectable extrasolar planet characteristics. We have used these data to upgrade, correct, and validate the NASA Astrobiology Institute's Virtual Planetary Laboratory three-dimensional line-by-line, multiple-scattering spectral Earth model. This comprehensive model now includes specular reflectance from the ocean and explicitly includes atmospheric effects such as Rayleigh scattering, gas absorption, and temperature structure. We have used this model to generate spatially and temporally resolved synthetic spectra and images of Earth for the dates of EPOXI observation. Model parameters were varied to yield an optimum fit to the data. We found that a minimum spatial resolution of ∼100 pixels on the visible disk, and four categories of water clouds, which were defined by using observed cloud positions and optical thicknesses, were needed to yield acceptable fits. The validated model provides a simultaneous fit to Earth's lightcurve, absolute brightness, and spectral data, with a root-mean-square (RMS) error of typically less than 3% for the multiwavelength lightcurves and residuals of ∼10% for the absolute brightness throughout the visible and NIR spectral range. We have extended our validation into the mid-infrared by comparing the model to high spectral resolution observations of Earth from the Atmospheric Infrared Sounder, obtaining a fit with residuals of ∼7% and brightness temperature errors of less than 1 K in the atmospheric window. For the purpose of understanding the observable characteristics of the distant Earth at arbitrary viewing geometry and observing cadence, our validated forward model can be

Earth as an extrasolar planet: Earth model validation using EPOXI earth observations.

PubMed

Robinson, Tyler D; Meadows, Victoria S; Crisp, David; Deming, Drake; A'hearn, Michael F; Charbonneau, David; Livengood, Timothy A; Seager, Sara; Barry, Richard K; Hearty, Thomas; Hewagama, Tilak; Lisse, Carey M; McFadden, Lucy A; Wellnitz, Dennis D

2011-06-01

The EPOXI Discovery Mission of Opportunity reused the Deep Impact flyby spacecraft to obtain spatially and temporally resolved visible photometric and moderate resolution near-infrared (NIR) spectroscopic observations of Earth. These remote observations provide a rigorous validation of whole-disk Earth model simulations used to better understand remotely detectable extrasolar planet characteristics. We have used these data to upgrade, correct, and validate the NASA Astrobiology Institute's Virtual Planetary Laboratory three-dimensional line-by-line, multiple-scattering spectral Earth model. This comprehensive model now includes specular reflectance from the ocean and explicitly includes atmospheric effects such as Rayleigh scattering, gas absorption, and temperature structure. We have used this model to generate spatially and temporally resolved synthetic spectra and images of Earth for the dates of EPOXI observation. Model parameters were varied to yield an optimum fit to the data. We found that a minimum spatial resolution of ∼100 pixels on the visible disk, and four categories of water clouds, which were defined by using observed cloud positions and optical thicknesses, were needed to yield acceptable fits. The validated model provides a simultaneous fit to Earth's lightcurve, absolute brightness, and spectral data, with a root-mean-square (RMS) error of typically less than 3% for the multiwavelength lightcurves and residuals of ∼10% for the absolute brightness throughout the visible and NIR spectral range. We have extended our validation into the mid-infrared by comparing the model to high spectral resolution observations of Earth from the Atmospheric Infrared Sounder, obtaining a fit with residuals of ∼7% and brightness temperature errors of less than 1 K in the atmospheric window. For the purpose of understanding the observable characteristics of the distant Earth at arbitrary viewing geometry and observing cadence, our validated forward model can be

Earth as an Extrasolar Planet: Earth Model Validation Using EPOXI Earth Observations

PubMed Central

Meadows, Victoria S.; Crisp, David; Deming, Drake; A'Hearn, Michael F.; Charbonneau, David; Livengood, Timothy A.; Seager, Sara; Barry, Richard K.; Hearty, Thomas; Hewagama, Tilak; Lisse, Carey M.; McFadden, Lucy A.; Wellnitz, Dennis D.

2011-01-01

Abstract The EPOXI Discovery Mission of Opportunity reused the Deep Impact flyby spacecraft to obtain spatially and temporally resolved visible photometric and moderate resolution near-infrared (NIR) spectroscopic observations of Earth. These remote observations provide a rigorous validation of whole-disk Earth model simulations used to better understand remotely detectable extrasolar planet characteristics. We have used these data to upgrade, correct, and validate the NASA Astrobiology Institute's Virtual Planetary Laboratory three-dimensional line-by-line, multiple-scattering spectral Earth model. This comprehensive model now includes specular reflectance from the ocean and explicitly includes atmospheric effects such as Rayleigh scattering, gas absorption, and temperature structure. We have used this model to generate spatially and temporally resolved synthetic spectra and images of Earth for the dates of EPOXI observation. Model parameters were varied to yield an optimum fit to the data. We found that a minimum spatial resolution of ∼100 pixels on the visible disk, and four categories of water clouds, which were defined by using observed cloud positions and optical thicknesses, were needed to yield acceptable fits. The validated model provides a simultaneous fit to Earth's lightcurve, absolute brightness, and spectral data, with a root-mean-square (RMS) error of typically less than 3% for the multiwavelength lightcurves and residuals of ∼10% for the absolute brightness throughout the visible and NIR spectral range. We have extended our validation into the mid-infrared by comparing the model to high spectral resolution observations of Earth from the Atmospheric Infrared Sounder, obtaining a fit with residuals of ∼7% and brightness temperature errors of less than 1 K in the atmospheric window. For the purpose of understanding the observable characteristics of the distant Earth at arbitrary viewing geometry and observing cadence, our validated forward

Earth Observation

NASA Image and Video Library

2013-08-03

Earth observation taken during day pass by an Expedition 36 crew member on board the International Space Station (ISS). Per Twitter message: From southernmost point of orbit over the South Pacific- all clouds seemed to be leading to the South Pole.

Earth Observation

NASA Image and Video Library

2013-07-21

Earth observation taken during night pass by an Expedition 36 crew member on board the International Space Station (ISS). Per Twitter message this is labeled as : Tehran, Iran. Lights along the coast of the Caspian Sea visible through clouds. July 21.

Earth Observation

NASA Image and Video Library

2014-06-12

Earth Observation taken during a day pass by the Expedition 40 crew aboard the International Space Station (ISS). Folder lists this as: Moon, Japan, Kamchatka with a wild cloud. Part of the U.S. Lab and PMM are also visible.

Earth Observation

NASA Image and Video Library

2014-05-31

Earth Observation taken during a day pass by the Expedition 40 crew aboard the International Space Station (ISS). Folder lists this as: CEO - Arena de Sao Paolo. View used for Twitter message: Cloudy skies over São Paulo Brazil

Impact of orbit modeling on DORIS station position and Earth rotation estimates

NASA Astrophysics Data System (ADS)

Štěpánek, Petr; Rodriguez-Solano, Carlos Javier; Hugentobler, Urs; Filler, Vratislav

2014-04-01

The high precision of estimated station coordinates and Earth rotation parameters (ERP) obtained from satellite geodetic techniques is based on the precise determination of the satellite orbit. This paper focuses on the analysis of the impact of different orbit parameterizations on the accuracy of station coordinates and the ERPs derived from DORIS observations. In a series of experiments the DORIS data from the complete year 2011 were processed with different orbit model settings. First, the impact of precise modeling of the non-conservative forces on geodetic parameters was compared with results obtained with an empirical-stochastic modeling approach. Second, the temporal spacing of drag scaling parameters was tested. Third, the impact of estimating once-per-revolution harmonic accelerations in cross-track direction was analyzed. And fourth, two different approaches for solar radiation pressure (SRP) handling were compared, namely adjusting SRP scaling parameter or fixing it on pre-defined values. Our analyses confirm that the empirical-stochastic orbit modeling approach, which does not require satellite attitude information and macro models, results for most of the monitored station parameters in comparable accuracy as the dynamical model that employs precise non-conservative force modeling. However, the dynamical orbit model leads to a reduction of the RMS values for the estimated rotation pole coordinates by 17% for x-pole and 12% for y-pole. The experiments show that adjusting atmospheric drag scaling parameters each 30 min is appropriate for DORIS solutions. Moreover, it was shown that the adjustment of cross-track once-per-revolution empirical parameter increases the RMS of the estimated Earth rotation pole coordinates. With recent data it was however not possible to confirm the previously known high annual variation in the estimated geocenter z-translation series as well as its mitigation by fixing the SRP parameters on pre-defined values.

The rotation of the sun - Observations at Stanford

NASA Technical Reports Server (NTRS)

Scherrer, P. H.; Wilcox, J. M.; Svalgaard, L.

1980-01-01

Daily observations of the photospheric rotation rate using the Doppler effect have been made at the Stanford Solar Observatory since May 1976. These observations show no daily or long-period variations in the rotation rate that exceed the observational error of about 1%. The average rotation rate is the same as that of the sunspots and the large-scale magnetic field structures.

Galvanic vestibular stimulation combines with Earth-horizontal rotation in roll to induce the illusion of translation.

PubMed

Schneider, Erich; Bartl, Klaus; Glasauer, Stefan

2009-05-01

Human head rotation in roll around an earth-horizontal axis constitutes a vestibular stimulus that, by its rotational component, acts on the semicircular canals (SCC) and that, by its tilt of the gravity vector, also acts on the otoliths. Galvanic vestibular stimulation (GVS) is thought to resemble mainly a rotation in roll. A superposition of sinusoidal GVS with a natural earth-horizontal roll movement was therefore applied in order to cancel the rotation effects and to isolate the otolith activation. By self-adjusting the amplitude and phase of GVS, subjects were able to minimize their sensation of rotation and to generate the perception of a linear translation. The final adjustments are in the range of a model that predicts SCC activation during natural rotations and GVS. This indicates that the tilt-translation ambiguity of the otoliths is resolved by SCC-otolith interaction. It is concluded that GVS might be able to cancel rotations in roll and that the residual tilt of the gravitoinertial force is possibly interpreted as a linear translation.

Observations of Rotating Sunspots from TRACE

NASA Astrophysics Data System (ADS)

Brown, D. S.; Nightingale, R. W.; Alexander, D.; Schrijver, C. J.; Metcalf, T. R.; Shine, R. A.; Title, A. M.; Wolfson, C. J.

2003-09-01

Recent observations from TRACE in the photospheric white-light channel have shown sunspots that rotate up to 200° about their umbral centre over a period of 3 5 days. The corresponding loops in the coronal fan are often seen to twist and can erupt as flares. In an ongoing study, seven cases of rotating sunspots have been identified, two of which can be associated with sigmoid structures appearing in Yohkoh/SXT and six with events seen by GOES. This paper analyzes the rotation rates of the sunspots using TRACE white-light data. Observations from AR 9114 are presented in detail in the main text and a summary of the results for the remaining six sunspots is presented in Appendixes A F. Discussion of the key results, particularly common features, are presented, as well as possible mechanisms for sunspot rotation.

Ocean tide models for satellite geodesy and Earth rotation

NASA Technical Reports Server (NTRS)

Dickman, Steven R.

1991-01-01

A theory is presented which predicts tides in turbulent, self-gravitating, and loading oceans possessing linearized bottom friction, realistic bathymetry, and continents (at coastal boundaries no-flow conditions are imposed). The theory is phrased in terms of spherical harmonics, which allows the tide equations to be reduced to linear matrix equations. This approach also allows an ocean-wide mass conservation constraint to be applied. Solutions were obtained for 32 long and short period luni-solar tidal constituents (and the pole tide), including the tidal velocities in addition to the tide height. Calibrating the intensity of bottom friction produces reasonable phase lags for all constituents; however, tidal amplitudes compare well with those from observation and other theories only for long-period constituents. In the most recent stage of grant research, traditional theory (Liouville equations) for determining the effects of angular momentum exchange on Earth's rotation were extended to encompass high-frequency excitations (such as short-period tides).

Analysis of earth rotation solution from Starlette

NASA Technical Reports Server (NTRS)

Schutz, B. E.; Cheng, M. K.; Shum, C. K.; Eanes, R. J.; Tapley, B. D.

1989-01-01

Earth rotation parameter (ERP) solutions were derived from the Starlette orbit analysis during the Main MERIT Campaign, using a technique of a consider-covariance analysis to assess the effects of errors on the polar motion solutions. The polar motion solution was then improved through the simultaneous adjustment of some dynamical parameters representing identified dominant perturbing sources (such as the geopotential and ocean-tide coefficients) on the polar motion solutions. Finally, an improved ERP solution was derived using the gravity field model, PTCF1, described by Tapley et al. (1986). The accuracy of the Starlette ERP solution was assessed by a comparison with the LAGEOS-derived ERP solutions.

Earth Observations

NASA Image and Video Library

2014-11-18

ISS042E006751 (11/08/2014) --- Earth observation taken from the International Space Station of the coastline of the United Arab Emirates. The large wheel along the coast center left is "Jumeirah" Palm Island, with a conference center, hotels, recreation areas and a large marine zoo.

The rotational motion of an earth orbiting gyroscope according to the Einstein theory of general relativity

NASA Technical Reports Server (NTRS)

Hoots, F. R.; Fitzpatrick, P. M.

1979-01-01

The classical Poisson equations of rotational motion are used to study the attitude motions of an earth orbiting, rapidly spinning gyroscope perturbed by the effects of general relativity (Einstein theory). The center of mass of the gyroscope is assumed to move about a rotating oblate earth in an evolving elliptic orbit which includes all first-order oblateness effects produced by the earth. A method of averaging is used to obtain a transformation of variables, for the nonresonance case, which significantly simplifies the Poisson differential equations of motion of the gyroscope. Long-term solutions are obtained by an exact analytical integration of the simplified transformed equations. These solutions may be used to predict both the orientation of the gyroscope and the motion of its rotational angular momentum vector as viewed from its center of mass. The results are valid for all eccentricities and all inclinations not near the critical inclination.

NASDA's earth observation satellite data archive policy for the earth observation data and information system (EOIS)

NASA Technical Reports Server (NTRS)

Sobue, Shin-ichi; Yoshida, Fumiyoshi; Ochiai, Osamu

1996-01-01

NASDA's new Advanced Earth Observing Satellite (ADEOS) is scheduled for launch in August, 1996. ADEOS carries 8 sensors to observe earth environmental phenomena and sends their data to NASDA, NASA, and other foreign ground stations around the world. The downlink data bit rate for ADEOS is 126 MB/s and the total volume of data is about 100 GB per day. To archive and manage such a large quantity of data with high reliability and easy accessibility it was necessary to develop a new mass storage system with a catalogue information database using advanced database management technology. The data will be archived and maintained in the Master Data Storage Subsystem (MDSS) which is one subsystem in NASDA's new Earth Observation data and Information System (EOIS). The MDSS is based on a SONY ID1 digital tape robotics system. This paper provides an overview of the EOIS system, with a focus on the Master Data Storage Subsystem and the NASDA Earth Observation Center (EOC) archive policy for earth observation satellite data.

Earth Observation

NASA Image and Video Library

2011-06-27

ISS028-E-009979 (27 June 2011) --- The Massachusetts coastline is featured in this image photographed by an Expedition 28 crew member on the International Space Station. The Crew Earth Observations team at NASA Johnson Space Center sends specific ground targets for photography up to the station crew on a daily basis, but sometimes the crew takes imagery on their own of striking displays visible from orbit. One such display, often visible to the ISS crew due to their ability to look outwards at angles between 0 and 90 degrees, is sunglint on the waters of Earth. Sunglint is caused by sunlight reflecting off of a water surface?much as light reflects from a mirror?directly towards the observer. Roughness variations of the water surface scatter the light, blurring the reflection and producing the typical silvery sheen of the sunglint area. The point of maximum sunglint is centered within Cape Cod Bay, the body of water partially enclosed by the ?hook? of Cape Cod in Massachusetts (bottom). Cape Cod was formally designated a National Seashore in 1966. Sunglint off the water provides sharp contrast with the coastline and the nearby islands of Martha?s Vineyard and Nantucket (lower left), both popular destinations for tourists and summer residents. To the north, rocky Cape Ann extends out into the Atlantic Ocean; the border with New Hampshire is located approximately 30 kilometers up the coast. Further to the west, the eastern half of Long Island, New York is visible emerging from extensive cloud cover over the mid-Atlantic and Midwestern States. Persistent storm tracks had been contributing to record flooding along rivers in the Midwest at the time this image was taken in late June 2011. Thin blue layers of the atmosphere, contrasted against the darkness of space, are visible extending along the Earth?s curvature at top.

Contributions of high-altitude winds and atmospheric moment of inertia to the atmospheric angular momentum-earth rotation relationship

NASA Technical Reports Server (NTRS)

Taylor, H. A., Jr.; Mayr, H. G.; Kramer, L.

1985-01-01

For many years it has been recognized that recurrent modulations occur in the time series of the earth's rotation rate or, alternatively, the change in the length of the day (Delta-LOD). Studies relating Delta-LOD to global patterns of zonal winds have confirmed that the variability of atmospheric angular momentum (M) is of sufficient magnitude to account for a large portion of the gross periodicities observed in the earth rotation. The present investigation is concerned with the importance of the contributions of the moment of inertia and high-altitude winds to the angular momentum budget. On the basis of an analysis of the various factors, it is found that within the available data, contributions of high-altitude winds and atmospheric moment of inertia reach levels detectable in the atmospheric angular momentum budget. Nevertheless, for the period December 1978 to December 1979 these contributions are not sufficient to resolve the apparent short-term discrepancies which are evident between Delta-LOD and M.

USGEO Common Framework For Earth Observation Data

NASA Astrophysics Data System (ADS)

Walter, J.; de la Beaujardiere, J.; Bristol, S.

2015-12-01

The United States Group on Earth Observations (USGEO) Data Management Working Group (DMWG) is an interagency body established by the White House Office of Science and Technology Policy (OSTP). The primary purpose of this group is to foster interagency cooperation and collaboration for improving the life cycle data management practices and interoperability of federally held earth observation data consistent with White House documents including the National Strategy for Civil Earth Observations, the National Plan for Civil Earth Observations, and the May 2013 Executive Order on Open Data (M-13-13). The members of the USGEO DMWG are working on developing a Common Framework for Earth Observation Data that consists of recommended standards and approaches for realizing these goals as well as improving the discoverability, accessibility, and usability of federally held earth observation data. These recommendations will also guide work being performed under the Big Earth Data Initiative (BEDI). This talk will summarize the Common Framework, the philosophy behind it, and next steps forward.

Earth Observation

NASA Image and Video Library

2014-09-01

Earth Observation taken during a night pass by the Expedition 40 crew aboard the International Space Station (ISS). Folder lists this as: New Zealand Aurora night pass. Docked Soyuz and Progress spacecraft are visible. On crewmember's Flickr page - The Moon, about to dive into a glowing ocean of green᥿9.

NASA's mission to planet Earth: Earth observing system

NASA Technical Reports Server (NTRS)

1993-01-01

The topics covered include the following: global climate change; radiation, clouds, and atmospheric water; the ocean; the troposphere - greenhouse gases; land cover and the water cycle; polar ice sheets and sea level; the stratosphere - ozone chemistry; volcanoes; the Earth Observing System (EOS) - how NASA will support studies of global climate change?; research and assessment - EOS Science Investigations; EOS Data and Information System (EOSDIS); EOS observations - instruments and spacecraft; a national international effort; and understanding the Earth System.

Semiconductor sensor for optically measuring polarization rotation of optical wavefronts using rare earth iron garnets

DOEpatents

Duncan, Paul G.

2002-01-01

Described are the design of a rare earth iron garnet sensor element, optical methods of interrogating the sensor element, methods of coupling the optical sensor element to a waveguide, and an optical and electrical processing system for monitoring the polarization rotation of a linearly polarized wavefront undergoing external modulation due to magnetic field or electrical current fluctuation. The sensor element uses the Faraday effect, an intrinsic property of certain rare-earth iron garnet materials, to rotate the polarization state of light in the presence of a magnetic field. The sensor element may be coated with a thin-film mirror to effectively double the optical path length, providing twice the sensitivity for a given field strength or temperature change. A semiconductor sensor system using a rare earth iron garnet sensor element is described.

Earth observing system: 1989 reference handbook

NASA Technical Reports Server (NTRS)

1989-01-01

NASA is studying a coordinated effort called the Mission to Planet Earth to understand global change. The goals are to understand the Earth as a system, and to determine those processes that contribute to the environmental balance, as well as those that may result in changes. The Earth Observing System (Eos) is the centerpiece of the program. Eos will create an integrated scientific observing system that will enable multidisciplinary study of the Earth including the atmosphere, oceans, land surface, polar regions, and solid Earth. Science goals, the Eos data and information system, experiments, measuring instruments, and interdisciplinary investigations are described.

Integration of the Rotation of an Earth-like Body as a Perturbed Spherical Rotor

NASA Astrophysics Data System (ADS)

Ferrer, Sebastián; Lara, Martin

2010-05-01

For rigid bodies close to a sphere, we propose an analytical solution that is free from elliptic integrals and functions, and can be fundamental for application to perturbed problems. After reordering the Hamiltonian as a perturbed spherical rotor, the Lie-series solution is generated up to an arbitrary order. Using the inertia parameters of different solar system bodies, the comparison of the approximate series solution with the exact analytical one shows that the precision reached with relatively low orders is at the same level of the observational accuracy for the Earth and Mars. Thus, for instance, the periodic errors of the mathematical solution are confined to the microarcsecond level with a simple second-order truncation for the Earth. On the contrary, higher orders are required for the mathematical solution to reach a precision at the expected level of accuracy of proposed new theories for the rotational dynamics of the Moon.

Moon-based Earth Observation for Large Scale Geoscience Phenomena

NASA Astrophysics Data System (ADS)

Guo, Huadong; Liu, Guang; Ding, Yixing

2016-07-01

The capability of Earth observation for large-global-scale natural phenomena needs to be improved and new observing platform are expected. We have studied the concept of Moon as an Earth observation in these years. Comparing with manmade satellite platform, Moon-based Earth observation can obtain multi-spherical, full-band, active and passive information,which is of following advantages: large observation range, variable view angle, long-term continuous observation, extra-long life cycle, with the characteristics of longevity ,consistency, integrity, stability and uniqueness. Moon-based Earth observation is suitable for monitoring the large scale geoscience phenomena including large scale atmosphere change, large scale ocean change,large scale land surface dynamic change,solid earth dynamic change,etc. For the purpose of establishing a Moon-based Earth observation platform, we already have a plan to study the five aspects as follows: mechanism and models of moon-based observing earth sciences macroscopic phenomena; sensors' parameters optimization and methods of moon-based Earth observation; site selection and environment of moon-based Earth observation; Moon-based Earth observation platform; and Moon-based Earth observation fundamental scientific framework.

Fast rotation of a subkilometer-sized near-Earth object 2011 XA{sub 3}

DOE Office of Scientific and Technical Information (OSTI.GOV)

Urakawa, Seitaro; Ohtsuka, Katsuhito; Abe, Shinsuke

2014-05-01

We present light curve observations and their multiband photometry for near-Earth object (NEO) 2011 XA{sub 3}. The light curve has shown a periodicity of 0.0304 ± 0.0003 days (= 43.8 ± 0.4 minutes). The fast rotation shows that 2011 XA{sub 3} is in a state of tension (i.e., a monolithic asteroid) and cannot be held together by self-gravitation. Moreover, the multiband photometric analysis indicates that the taxonomic class of 2011 XA{sub 3} is S-complex, or V-type. Its estimated effective diameter is 225 ± 97 m (S-complex) and 166 ± 63 m (V-type), respectively. Therefore, 2011 XA{sub 3} is a candidatemore » for the second-largest, fast-rotating, monolithic asteroid. Moreover, the orbital parameters of 2011 XA{sub 3} are apparently similar to those of NEO (3200) Phaethon, but F/B-type. We computed the orbital evolutions of 2011 XA{sub 3} and Phaethon. However, the results of the computation and distinct taxonomy indicate that neither of the asteroids is of common origin.« less

Observing the ExoEarth: Simulating the Retrieval of Exoplanet Parameters Using DSCOVR

NASA Astrophysics Data System (ADS)

Kane, S.; Cowan, N. B.; Domagal-Goldman, S. D.; Herman, J. R.; Robinson, T.; Stine, A.

2017-12-01

The field of exoplanets has rapidly expanded from detection to include exoplanet characterization. This has been enabled by developments such as the detection of terrestrial-sized planets and the use of transit spectroscopy to study exoplanet atmospheres. Studies of rocky planets are leading towards the direct imaging of exoplanets and the development of techniques to extract their intrinsic properties. The importance of properties such as rotation, albedo, and obliquity are significant since they inform planet formation theories and are key input parameters for Global Circulation Models used to determine surface conditions, including habitability. Thus, a complete characterization of exoplanets for understanding habitable climates requires the ability to measure these key planetary parameters. The retrieval of planetary rotation rates, albedos, and obliquities from highly undersampled imaging data can be honed using satellites designed to study the Earth's atmosphere. In this talk I will describe how the Deep Space Climate Observatory (DSCOVR) provides a unique opportunity to test such retrieval methods using data for the sunlit hemisphere of the Earth. Our methods use the high-resolution DSCOVR-EPIC images to simulate the Earth as an exoplanet, by deconvolving the images to match a variety of expected exoplanet mission requirements, and by comparing EPIC data with the cavity radiometer data from DSCOVR-NISTAR that views the Earth as a single pixel. Through this methodology, we are creating a grid of retrieval states as a function of image resolution, observing cadence, passband, etc. Our modeling of the DSCOVR data will provide an effective baseline from which to develop tools that can be applied to a variety of exoplanet imaging data.

Measurement of diurnal and semidiurnal rotational variations and tidal parameters of Earth

NASA Technical Reports Server (NTRS)

Herring, Thomas A.; Dong, Danan

1994-01-01

We discuss the determination of diurnal and semidiurnal variations in the rotation rate and the direction of rotation axis of Earth from the analysis of 8 years of very long baseline interferometry (VLBI) data. This analysis clearly show that these variations are largely periodic and tidally driven; that is, the periods of the variations correspond to the periods of the largest lunar and solar tides. For rotation rate variations, expressed in terms of changes in universal time (UT), the tidal lines with the largest observed signals are O1 (amplitude 23.5 microseconds in time (microseconds), period 25.82 solar hours); KL (18.9 microseconds, 23.93 hours); M2 (17.9 microseconds, 12.54 hours); and S2 (8.6 microseconds, 12.00 hours). For variations in the direction of the rotation axis (polar motion), significant signals exist in the retrograde semidiurnal band at the M2 and S2 tides (amplitudes 265 and 119 microarc seconds (microarc seconds, respectively); the prograde diurnal band at the O1, K1, and P1 tides (amplitudes 199, 152, and 60 microarc seconds, respectively); and the prograde semidiurnal band at the M2 and K2 tides (amplitudes 58 and 39 microarc seconds, respectively). Variations in the retrograde diurnal band are represented by corrections with previous estimates except that a previously noted discrepancy in the 13.66-day nutation (corresponding to the O1 tide) is largely removed in this new analysis. We estimate that the standard deviations of these estimates are 1.0 microseconds for the UT1 variations and 14-16 microarc seconds for the polar motion terms. These uncertainties correspond to surface displacements of approximately 0.5 mm. From the analysis of atmospheric angular momentum data we conclude that variations in UT1 excited by the atmosphere with subdaily periods are small (approximately 1 microsecond). We find that the average radial tidal displacements of the VLBI sites in the diurnal band are largely consistent with known deficiencies in current

Snow load effect on earth's rotation and gravitational field, 1979-1985

NASA Technical Reports Server (NTRS)

Chao, B. Fong; O'Connor, William P.; Chang, Alfred T. C.; Hall, Dorothy K.; Foster, James L.

1987-01-01

A global, monthly snow depth data set has been generated from the Nimbus 7 satellite observations using passive microwave remote-sensing techniques. Seven years of data, 1979-1985, are analyzed to compute the snow load effects on the earth's rotation and low-degree zonal gravitational field. The resultant time series show dominant seasonal cycles. The annual peak-to-peak variation in J2 is found to be 2.3 x 10 to the -10th, that in J3 to be 1.1 x 10 to the -10th, and believed to decrease rapidly for higher degrees. The corresponding change in the length of day is 41 micro-s. The annual wobble excitation is (4.9 marc sec, -109 deg) for the prograde motion component and (4.8 marc sec, -28 deg) for the retrograde motion component. The excitation power of the Chandler wobble due to the snow load is estimated to be about 25 dB less than the power needed to maintain the observed Chandler wobble.

Lunar-based Earth observation geometrical characteristics research

NASA Astrophysics Data System (ADS)

Ren, Yuanzhen; Liu, Guang; Ye, Hanlin; Guo, Huadong; Ding, Yixing; Chen, Zhaoning

2016-07-01

As is known to all, there are various platforms for carrying sensors to observe Earth, such as automobiles, aircrafts and satellites. Nowadays, we focus on a new platform, Moon, because of its longevity, stability and vast space. These advantages make it to be the next potential platform for observing Earth, enabling us to get the consistent and global measurements. In order to get a better understanding of lunar-based Earth observation, we discuss its geometrical characteristics. At present, there are no sensors on the Moon for observing Earth and we are not able to obtain a series of real experiment data. As a result, theoretical modeling and numerical calculation are used in this paper. At first, we construct an approximate geometrical model of lunar-based Earth observation, which assumes that Earth and Moon are spheres. Next, we calculate the position of Sun, Earth and Moon based on the JPL ephemeris. With the help of positions data and geometrical model, it is possible for us to decide the location of terminator and substellar points. However, in order to determine their precise position in the conventional terrestrial coordinate system, reference frames transformations are introduced as well. Besides, taking advantages of the relative positions of Sun, Earth and Moon, we get the total coverage of lunar-based Earth optical observation. Furthermore, we calculate a more precise coverage, considering placing sensors on different positions of Moon, which is influenced by its attitude parameters. In addition, different ephemeris data are compared in our research and little difference is found.

Observations and analysis of Alfvén wave phase mixing in the Earth's magnetosphere

NASA Astrophysics Data System (ADS)

Sarris, T. E.; Wright, A. N.; Li, X.

2009-03-01

Signatures of Alfvén wave phase mixing in the Earth's magnetosphere, observed as polarization rotation of a transverse, Pc5 magnetospheric pulsation, are presented and compared to theory. The polarization rotation occurred during a rare event of a dayside narrowband ULF magnetospheric pulsation that lasted for 5 consecutive days, from 24 to 30 November 1997; details of this event were reported by Sarris et al. (2009) through observations at geosynchronous orbit and on the ground. In this paper we investigate the polarization signatures of the pulsation by performing a detailed analysis of its transverse components as observed through hodogram plots. Density measurements from one of the Los Alamos National Laboratory (LANL) spacecraft which had its L shells closest to GOES-8 are used to calculate field line resonance frequencies at geosynchronous orbit; these frequency calculations show good agreement with the observed pulsations but also have a local time offset. For an instance of an observed polarization rotation we estimate the observed poloidal lifetime of the pulsation by the time taken for the poloidal and toroidal amplitudes to become equal, which we compare with the theoretical approximation to the poloidal lifetime, as calculated in a box model magnetosphere by Mann and Wright (1995). Density measurements from different LANL spacecraft at geosynchronous orbit and their varying L shells as derived from their varying local times are used to estimate a local gradient in the local Alfvén speed, which is then used in the calculation of the predicted poloidal lifetime. This is the first time that such polarization rotations are directly observed and compared with theoretical predictions.

Extreme-ultraviolet observations of global coronal wave rotation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Attrill, G. D. R.; Long, D. M.; Green, L. M.

2014-11-20

We present evidence of global coronal wave rotation in EUV data from SOHO/EIT, STEREO/EUVI, and SDO/AIA. The sense of rotation is found to be consistent with the helicity of the source region (clockwise for positive helicity, anticlockwise for negative helicity), with the source regions hosting sigmoidal structures. We also study two coronal wave events observed by SDO/AIA where no clear rotation (or sigmoid) is observed. The selected events show supporting evidence that they all originate with flux rope eruptions. We make comparisons across this set of observations (both with and without clear sigmoidal structures). On examining the magnetic configuration ofmore » the source regions, we find that the nonrotation events possess a quadrupolar magnetic configuration. The coronal waves that do show a rotation originate from bipolar source regions.« less

Observations of Near-Earth Asteroids at Abastumani Astrophysical Observatory

NASA Astrophysics Data System (ADS)

Krugly, Yurij; Ayvazyan, Vova; Inasaridze, Raguli; Zhuzhunadze, Vasili; Molotov, Igor; Voropaev, Victor; Rumyantsev, Vasilij; Baransky, Alexander

Over the past five years physical properties of near-Earth asteroids are investigated in the Kharadze Abastumani Astrophysical Observatory. The work was launched in the collaboration with Kharkiv Institute of Astronomy within the Memorandum on scientific cooperation between Ilia State University (Georgia) and V. N. Karazin Kharkiv National University (Ukraine) in 2011. In the framework of this study the regular observations of several dozen asteroids per year are carried out to determine the rotation periods, size and shape parameters of these celestial bodies. A broad international cooperation is involved in order to improve the efficiency of the study. Abastumani is included in the observatory network called the Gaia -FUN-SSO, which was created for the ground support of the ESA's Gaia space mission.

Effects of the observed J2 variations on the Earth's precession and nutation

NASA Astrophysics Data System (ADS)

Ferrándiz, José M.; Baenas, Tomás; Belda, Santiago

2016-04-01

The Earth's oblateness parameter J2 is closely related to the dynamical ellipticity H, which factorizes the main components of the precession and the different nutation terms. In most theoretical approaches to the Earth's rotation, with IAU2000 nutation theory among them, H is assumed to be constant. The precession model IAU2006 supposes H to have a conventional linear variation, based on the J2 time series derived mainly from satellite laser ranging (SLR) data for decades, which gives rise to an additional quadratic term of the precession in longitude and some corrections of the nutation terms. The time evolution of J2 is, however, too complex to be well approximated by a simple linear model. The effect of more general models including periodic terms and closer to the observed time series, although still unable to reproduce a significant part of the signal, has been seldom investigated. In this work we address the problem of deriving the effect of the observed J2 variations without resorting to such simplified models. The Hamiltonian approach to the Earth rotation is extended to allow the McCullagh's term of the potential to depend on a time-varying oblateness. An analytical solution is derived by means of a suitable perturbation method in the case of the time series provided by the Center for Space Research (CSR) of the University of Texas, which results in non-negligible contributions to the precession-nutation angles. The presentation focuses on the main effects on the longitude of the equator; a noticeable non-linear trend is superimposed to the linear main precession term, along with some periodic and decadal variations.

Observations from earth orbit and variability of the polar aurora on Jupiter

NASA Technical Reports Server (NTRS)

Clarke, J. T.; Moos, H. W.; Atreya, S. K.; Lane, A. L.

1980-01-01

Spatially resolved spectra of Jupiter taken with the International Ultraviolet Explorer satellite show enhanced emissions from the polar regions at H L-alpha (1216 A) and in the Lyman and Werner bands of H2 (1175-1650 A). Two types of variability in emission brightness have been observed in these aurorae: an increase in the observed emission as the auroral oval rotates with Jupiter's magnetic pole to face toward the earth and a general variation in brightness of more than an order of magnitude under nearly identical observing conditions. In addition, the spectral character of these aurorae (determined by the ratio of H L-alpha to H2 brightnesses) appears variable, indicating that the depth of penetration of the auroral particles is not constant.

The Earth Observing System

NASA Technical Reports Server (NTRS)

Shaffer, Lisa Robock

1992-01-01

The restructuring of the NASA Earth Observing System (EOS), designed to provide comprehensive long term observations from space of changes occurring on the Earth from natural and human causes in order to have a sound scientific basis for policy decisions on protection of the future, is reported. In response to several factors, the original program approved in the fiscal year 1991 budget was restructured and somewhat reduced in scope. The resulting program uses three different sized launch vehicles to put six different spacecraft in orbit in the first phase, followed by two replacement launches for each of five of the six satellites to maintain a long term observing capability to meet the needs of global climate change research and other science objectives. The EOS system, including the space observatories, the data and information system, and the interdisciplinary global change research effort, are approved and proceeding. Elements of EOS are already in place, such as the research investigations and initial data system capabilities. The flights of precursor satellite and Shuttle missions, the ongoing data analysis, and the evolutionary enhancements to the integrated Earth science data management capabilities are all important building blocks to the full EOS program.

An Algorithm for Converting Static Earth Sensor Measurements into Earth Observation Vectors

NASA Technical Reports Server (NTRS)

Harman, R.; Hashmall, Joseph A.; Sedlak, Joseph

2004-01-01

An algorithm has been developed that converts penetration angles reported by Static Earth Sensors (SESs) into Earth observation vectors. This algorithm allows compensation for variation in the horizon height including that caused by Earth oblateness. It also allows pitch and roll to be computed using any number (greater than 1) of simultaneous sensor penetration angles simplifying processing during periods of Sun and Moon interference. The algorithm computes body frame unit vectors through each SES cluster. It also computes GCI vectors from the spacecraft to the position on the Earth's limb where each cluster detects the Earth's limb. These body frame vectors are used as sensor observation vectors and the GCI vectors are used as reference vectors in an attitude solution. The attitude, with the unobservable yaw discarded, is iteratively refined to provide the Earth observation vector solution.

Earth's gravity gradient and eddy currents effects on the rotational dynamics of space debris objects: Envisat case study

NASA Astrophysics Data System (ADS)

Gómez, Natalia Ortiz; Walker, Scott J. I.

2015-08-01

The space debris population has grown rapidly over the last few decades with the consequent growth of impact risk between current objects in orbit. Active Debris Removal (ADR) has been recommended to be put into practice by several National Agencies in order to remove objects that pose the biggest risk for the space community. The most immediate target that is being considered for ADR by the European Space Agency is the Earth-observing satellite Envisat. In order to safely remove such a massive object from its orbit, a capturing process followed by a controlled reentry is necessary. However, current ADR methods that require physical contact with the target have limitations on the maximum angular momentum that can be absorbed and a de-tumbling phase prior to the capturing process may be required. Therefore, it is of utmost importance for the ADR mission design to be able to predict accurately how the target will be rotating at the time of capture. This article analyses two perturbations that affect an object in Low Earth Orbit (LEO), the Earth's gravity gradient and the eddy currents induced by the Earth's magnetic field. The gravity gradient is analysed using the equation of conservation of total energy and a graphical method is presented to understand the expected behaviour of any object under the effect of this perturbation. The eddy currents are also analysed by studying the total energy of the system. The induced torque and the characteristic time of decay are presented as a function of the object's magnetic tensor. In addition, simulations were carried out for the Envisat spacecraft including the gravity gradient perturbation as well as the eddy currents effect using the International Geomagnetic Reference Field IGRF-11 to model the Earth's magnetic field. These simulations show that the combined effect of these two perturbations is a plausible explanation for the rotational speed decay observed between April 2013 and September 2013.

Estimation of accuracy of earth-rotation parameters in different frequency bands

NASA Astrophysics Data System (ADS)

Vondrak, J.

1986-11-01

The accuracies of earth-rotation parameters as determined by five different observational techniques now available (i.e., optical astrometry /OA/, Doppler tracking of satellites /DTS/, satellite laser ranging /SLR/, very long-base interferometry /VLBI/ and lunar laser ranging /LLR/) are estimated. The differences between the individual techniques in all possible combinations, separated by appropriate filters into three frequency bands, were used to estimate the accuracies of the techniques for periods from 0 to 200 days, from 200 to 1000 days and longer than 1000 days. It is shown that for polar motion the most accurate results are obtained with VLBI anad SLR, especially in the short-period region; OA and DTS are less accurate, but with longer periods the differences in accuracy are less pronounced. The accuracies of UTI-UTC as determined by OA, VLBI and LLR are practically equivalent, the differences being less than 40 percent.

Reconnection at the earth's magnetopause - Magnetic field observations and flux transfer events

NASA Technical Reports Server (NTRS)

Russell, C. T.

1984-01-01

Theoretical models of plasma acceleration by magnetic-field-line reconnection at the earth magnetopause and the high-resolution three-dimensional plasma measurements obtained with the ISEE satellites are compared and illustrated with diagrams, graphs, drawings, and histograms. The history of reconnection theory and the results of early satellite observations are summarized; the thickness of the magnetopause current layer is discussed; problems in analyzing the polarization of current-layer rotation are considered; and the flux-transfer events responsible for periods of patchy reconnection are characterized in detail. The need for further observations and refinements of the theory to explain the initiation of reconnection and identify the mechanism determining whether it is patchy or steady-state is indicated.

The Sub-bureau for Atmospheric Angular Momentum of the International Earth Rotation Service - A meteorological data center with geodetic applications

NASA Technical Reports Server (NTRS)

Salstein, David A.; Kann, Deirdre M.; Miller, Alvin J.; Rosen, Richard D.

1993-01-01

By exchanging angular momentum with the solid portion of the earth, the atmosphere plays a vital role in exciting small but measurable changes in the rotation of our planet. Recognizing this relationship, the International Earth Rotation Service invited the U.S. National Meteorological Center to organize a Sub-bureau for Atmospheric Angular Momentum (SBAAM) for the purpose of collecting, distributing, archiving, and analyzing atmospheric parameters relevant to earth rotation/polar motion. These functions of wind and surface pressure are being computed with data from several of the world's weather services, and they are being widely applied to the research and operations of the geodetic community. The SBAAM began operating formally in October 1989, and this article highlights its development, operations, and significance.

Deep Space Earth Observations from DSCOVR

NASA Astrophysics Data System (ADS)

Marshak, A.; Herman, J.

2018-02-01

The Deep Space Climate Observatory (DSCOVR) at Sun-Earth L1 orbit observes the full sunlit disk of Earth. There are two Earth science instruments on board DSCOVR — EPIC and NISTAR. We discuss if EPIC and NISAR-like instruments can be used in Deep Space Gateway.

Project of a laser gyroscope to determine continuously the Earth's rotation.

NASA Astrophysics Data System (ADS)

Blinov, N. S.; Zharov, V. E.; Sazhin, M. V.; Fedoseev, E. N.; Vlasov, B. I.; Rusakov, V. K.

The Time Service of the Sternberg State Astronomical Institute together with specialists of VNIIFTRI began to work at the project of the laser gyroscope to determine continuously the Earth's rotation. It is assumed to measure both the high-frequency variations with periods of 100 - 1000 sec and the low-frequency variations with periods of a few days. It gives the opportunity to combine these data with the VLBI data.

1993 Earth Observing System reference handbook

NASA Technical Reports Server (NTRS)

Asrar, Ghassem (Editor); Dokken, David Jon (Editor)

1993-01-01

Mission to Planet Earth (MTPE) is a NASA-sponsored concept that uses space- and ground-based measurement systems to provide the scientific basis for understanding global change. The space-based components of MTPE will provide a constellation of satellites to monitor the Earth from space. Sustained observations will allow researchers to monitor climate variables overtime to determine trends; however, space-based monitoring alone is not sufficient. A comprehensive data and information system, a community of scientists performing research with the data acquired, and extensive ground campaigns are all important components. Brief descriptions of the various elements that comprise the overall mission are provided. The Earth Observing System (EOS) - a series of polar-orbiting and low-inclination satellites for long-term global observations of the land surface, biosphere, solid Earth, atmosphere, and oceans - is the centerpiece of MTPE. The elements comprising the EOS mission are described in detail.

Earth Observing System Covariance Realism Updates

NASA Technical Reports Server (NTRS)

Ojeda Romero, Juan A.; Miguel, Fred

2017-01-01

This presentation will be given at the International Earth Science Constellation Mission Operations Working Group meetings June 13-15, 2017 to discuss the Earth Observing System Covariance Realism updates.

Observing earth from Skylab

NASA Technical Reports Server (NTRS)

1975-01-01

Skylab technology and observations of earth resources are discussed. Special attention was given to application of Skylab data to mapmaking, geology/geodesy, water resources, oceanography, meteorology, and geography/ecology.

COMS normal operation for Earth Observation mission

NASA Astrophysics Data System (ADS)

Cho, Young-Min

2012-09-01

Communication Ocean Meteorological Satellite (COMS) for the hybrid mission of meteorological observation, ocean monitoring, and telecommunication service was launched onto Geostationary Earth Orbit on June 27, 2010 and it is currently under normal operation service since April 2011. The COMS is located on 128.2° East of the geostationary orbit. In order to perform the three missions, the COMS has 3 separate payloads, the meteorological imager (MI), the Geostationary Ocean Color Imager (GOCI), and the Ka-band antenna. Each payload is dedicated to one of the three missions, respectively. The MI and GOCI perform the Earth observation mission of meteorological observation and ocean monitoring, respectively. For this Earth observation mission the COMS requires daily mission commands from the satellite control ground station and daily mission is affected by the satellite control activities. For this reason daily mission planning is required. The Earth observation mission operation of COMS is described in aspects of mission operation characteristics and mission planning for the normal operation services of meteorological observation and ocean monitoring. And the first year normal operation results after the In-Orbit-Test (IOT) are investigated through statistical approach to provide the achieved COMS normal operation status for the Earth observation mission.

Ocean angular momentum signals in a climate model and implications for Earth rotation

NASA Astrophysics Data System (ADS)

Ponte, R. M.; Rajamony, J.; Gregory, J. M.

2002-03-01

Estimates of ocean angular momentum (OAM) provide an integrated measure of variability in ocean circulation and mass fields and can be directly related to observed changes in Earth rotation. We use output from a climate model to calculate 240 years of 3-monthly OAM values (two equatorial terms L1 and L2, related to polar motion or wobble, and axial term L3, related to length of day variations) representing the period 1860-2100. Control and forced runs permit the study of the effects of natural and anthropogenically forced climate variability on OAM. All OAM components exhibit a clear annual cycle, with large decadal modulations in amplitude, and also longer period fluctuations, all associated with natural climate variability in the model. Anthropogenically induced signals, inferred from the differences between forced and control runs, include an upward trend in L3, related to inhomogeneous ocean warming and increases in the transport of the Antarctic Circumpolar Current, and a significantly weaker seasonal cycle in L2 in the second half of the record, related primarily to changes in seasonal bottom pressure variability in the Southern Ocean and North Pacific. Variability in mass fields is in general more important to OAM signals than changes in circulation at the seasonal and longer periods analyzed. Relation of OAM signals to changes in surface atmospheric forcing are discussed. The important role of the oceans as an excitation source for the annual, Chandler and Markowitz wobbles, is confirmed. Natural climate variability in OAM and related excitation is likely to measurably affect the Earth rotation, but anthropogenically induced effects are comparatively weak.

The U.S. National Plan for Civil Earth Observations

NASA Astrophysics Data System (ADS)

Stryker, T.; Clavin, C.; Gallo, J.

2014-12-01

Globally, the United Sates Government is one of the largest providers of environmental and Earth-system data. As the nation's Earth observation capacity has grown, so have the complexity and challenges associated with managing Earth observation systems and related data holdings. In July 2014, the White House Office of Science and Technology Policy released the first-ever National Plan for Civil Earth Observations to address these challenges. The Plan provides a portfolio management-based framework for maximizing the value of Federal Earth observations. The Plan identifies Federal priorities for Earth observations and improved management of their data. Through routine assessments, expanding data management efforts, interagency planning, and international collaboration, OSTP and its partner agencies will seek ensure the continued provision of and access to key Earth observation data, which support a broad range of public services and research programs. The presenters will provide a detailed review of the components of the National Plan, its impacts across the Federal agencies involved in Earth observations, and associated efforts to enable interagency coordination.

Revised Atmospheric Angular Momentum Series Related to Earth's Variable Rotation under Consideration of Surface Topography

NASA Technical Reports Server (NTRS)

Zhou, Y. H.; Salstein, D. A.; Chen, J. L.

2006-01-01

The atmospheric angular momentum is closely related to variations in the Earth rotation. The atmospheric excitation function (AEF), or namely atmospheric effective angular momentum function, is introduced in studying the atmospheric excitation of the Earth's variable rotation. It may be separated into two portions, i.e, the "wind" terms due to the atmospheric motion relative to the mantle and the "pressure" terms due to the variations of atmospheric mass distribution evident through surface pressure changes. The AEF wind terms during the period of 1948-2004 are re-processed from the NCEP/NCAR (National Centers for Environmental Prediction-National Center for Atmospheric Research) reanalysis 6-hourly wind and pressure fields. Some previous calculations were approximate, in that the wind terms were integrated from an isobaric lower boundary of 1000 hPa. To consider the surface topography effect, however, the AEF is computed by integration using the winds from the Earth's surface to 10 hPa, the top atmospheric model level, instead of from 1000 hPa. For these two cases, only a minor difference, equivalent to approx. 0.004 milliseconds in length-of-day variation, exists with respect to the axial wind term. However, considerable differences, equivalent to 5-6 milliarcseconds in polar motion, are found regarding equatorial wind terms. We further compare the total equatorial AEF (with and without the topographic effect) with the polar motion excitation function (PMEF) during the period of 1980-2003. The equatorial AEF gets generally closer to the PMEF, and improved coherences are found between them when the topography effect is included. Keywords: Atmospheric angular momentum, Atmospheric excitation function, Earth rotation, Topography, Wind, Pressure.

Rotational-oscillational motions of the nonrigid Earth about the center of mass

NASA Astrophysics Data System (ADS)

Bondarenko, V. V.; Perepelkin, V. V.

2009-10-01

We use the model of a nearly axisymmetric viscoelastic rigid body to study perturbed rotational-oscillational motions of the Earth's pole. We point out that the Chandler component of oscillations is of celestial-mechanics nature and is caused by the gravitational-tidal actions of the Sun and the Moon. We analyze the pole oscillation excitation mechanism at a frequency close to the Chandler frequency and show that the undamped pole oscillations are caused by the resonance harmonic of the external perturbation at a frequency close to the free nutation frequency. We discuss whether it is possible to solve the problem of constructing a short-term forecast of the pole motion on the basis of a polynomial filter obtained by the least-squares method without taking into account small-scale oscillations caused by wide-band random factors of arbitrary physical nature. In the present paper, we perform numerical simulation of tidal inhomogeneities in the Earth's axial rotation. Attention is mainly paid to the analysis of day length variations on short time intervals with periods less than or equal to one year (interannual oscillations) and to their forecast.

The Earth Observation Technology Cluster

NASA Astrophysics Data System (ADS)

Aplin, P.; Boyd, D. S.; Danson, F. M.; Donoghue, D. N. M.; Ferrier, G.; Galiatsatos, N.; Marsh, A.; Pope, A.; Ramirez, F. A.; Tate, N. J.

2012-07-01

The Earth Observation Technology Cluster is a knowledge exchange initiative, promoting development, understanding and communication about innovative technology used in remote sensing of the terrestrial or land surface. This initiative provides an opportunity for presentation of novel developments from, and cross-fertilisation of ideas between, the many and diverse members of the terrestrial remote sensing community. The Earth Observation Technology Cluster involves a range of knowledge exchange activities, including organisation of technical events, delivery of educational materials, publication of scientific findings and development of a coherent terrestrial EO community. The initiative as a whole covers the full range of remote sensing operation, from new platform and sensor development, through image retrieval and analysis, to data applications and environmental modelling. However, certain topical and strategic themes have been selected for detailed investigation: (1) Unpiloted Aerial Vehicles, (2) Terrestrial Laser Scanning, (3) Field-Based Fourier Transform Infra-Red Spectroscopy, (4) Hypertemporal Image Analysis, and (5) Circumpolar and Cryospheric Application. This paper presents general activities and achievements of the Earth Observation Technology Cluster, and reviews state-of-the-art developments in the five specific thematic areas.

Axis of Eye Rotation Changes with Head-Pitch Orientation during Head Impulses about Earth-Vertical

PubMed Central

Schubert, Michael C.; Clendaniel, Richard A.; Carey, John P.; Della Santina, Charles C.; Minor, Lloyd B.; Zee, David S.

2006-01-01

The goal of this study was to assess how the axis of head rotation, Listing's law, and eye position influence the axis of eye rotation during brief, rapid head rotations. We specifically asked how the axis of eye rotation during the initial angular vestibuloocular reflex (VOR) changed when the pitch orientation of the head relative to Earth-vertical was varied, but the initial position of the eye in the orbit and the orientation of Listing's plane with respect to the head were fixed. We measured three-dimensional eye and head rotation axes in eight normal humans using the search coil technique during head-and-trunk (whole-body) and head-on-trunk (head-only) “impulses” about an Earth-vertical axis. The head was initially oriented at one of five pitch angles (30° nose down, 15° nose down, 0°, 15° nose up, 30° nose up). The fixation target was always aligned with the nasooccipital axis. Whole-body impulses were passive, unpredictable, manual, rotations with peak-amplitude of ∼20°, peak-velocity of ∼80°/s, and peak-acceleration of ∼1000°/s2. Head-only impulses were also passive, unpredictable, manual, rotations with peak-amplitude of ∼20°, peak-velocity of ∼150°/s, and peak-acceleration of ∼3000°/s2. During whole-body impulses, the axis of eye rotation tilted in the same direction, and by an amount proportional (0.51 ± 0.09), to the starting pitch head orientation (P < 0.05). This proportionality constant decreased slightly to 0.39 ± 0.08 (P < 0.05) during head-only impulses. Using the head-only impulse data, with the head pitched up, we showed that only 50% of the tilt in the axis of eye rotation could be predicted from vectorial summation of the gains (eye velocity/head velocity) obtained for rotations about the pure yaw and roll head axes. Thus, even when the orientation of Listing's plane and eye position in the orbit are fixed, the axis of eye rotation during the VOR reflects a compromise between the requirements of Listing's law and a

Earth Observation

NASA Image and Video Library

2016-04-20

ISS047e069406 (04/20/2016) ---Earth observation image taken by the Expedition 47 crew aboard the International Space Station. This is an oblique south-looking view of the main Bahama island chain. Cuba is across the entire top of the image, the Florida Peninsula on the right margin. In the Bahamas, the main Andros island is just distinguishable under cloud upper left of center. Under less cloud is the Abaco Islands in the foreground (middle of pic nearest camera left of center.)

Arecibo Radar Observations of Near-Earth Asteroids

NASA Astrophysics Data System (ADS)

Rivera-Valentin, Edgard G.; Taylor, Patrick A.; Virkki, Anne; Saran Bhiravarasu, Sriram; Venditti, Flaviane; Zambrano-Marin, Luisa Fernanda; Aponte-Hernandez, Betzaida

2017-10-01

The Arecibo S-Band (2.38 GHz, 12.6 cm; 1 MW) planetary radar system at the 305-m William E. Gordon Telescope in Arecibo, Puerto Rico is the most active, most powerful, and most sensitive planetary radar facility in the world. As such, Arecibo is vital for post-discovery characterization and orbital refinement of near-Earth asteroids. Since August 2016, the program has observed 100 near-Earth asteroids (NEAs), of which 38 are classified as potentially hazardous to Earth and 31 are compliant with the NASA Near-Earth Object Human Space Flight Accessible Targets Study (NHATS). Arecibo observations are critical for identifying NEAs that may be on a collision course with Earth in addition to providing detailed physical characterization of the objects themselves in terms of size, shape, spin, and surface properties, which are valuable for assessing impact mitigation strategies. Here, we will present a sampling of the asteroid zoo observed by Arecibo, including press-noted asteroids 2014 JO25 and the (163693) Atira binary system.

Connecting Earth observation to high-throughput biodiversity data.

PubMed

Bush, Alex; Sollmann, Rahel; Wilting, Andreas; Bohmann, Kristine; Cole, Beth; Balzter, Heiko; Martius, Christopher; Zlinszky, András; Calvignac-Spencer, Sébastien; Cobbold, Christina A; Dawson, Terence P; Emerson, Brent C; Ferrier, Simon; Gilbert, M Thomas P; Herold, Martin; Jones, Laurence; Leendertz, Fabian H; Matthews, Louise; Millington, James D A; Olson, John R; Ovaskainen, Otso; Raffaelli, Dave; Reeve, Richard; Rödel, Mark-Oliver; Rodgers, Torrey W; Snape, Stewart; Visseren-Hamakers, Ingrid; Vogler, Alfried P; White, Piran C L; Wooster, Martin J; Yu, Douglas W

2017-06-22

Understandably, given the fast pace of biodiversity loss, there is much interest in using Earth observation technology to track biodiversity, ecosystem functions and ecosystem services. However, because most biodiversity is invisible to Earth observation, indicators based on Earth observation could be misleading and reduce the effectiveness of nature conservation and even unintentionally decrease conservation effort. We describe an approach that combines automated recording devices, high-throughput DNA sequencing and modern ecological modelling to extract much more of the information available in Earth observation data. This approach is achievable now, offering efficient and near-real-time monitoring of management impacts on biodiversity and its functions and services.

Effects of Faraday Rotation Observed in Filter Magnetograph Data

NASA Technical Reports Server (NTRS)

Hagyard, Mona J.; Adams, Mitzi L.; Smith, J. E.; West, Edward A.

1999-01-01

In this paper we analyze the effects of Faraday rotation on the azimuth of the transverse magnetic field from observations taken with the Marshall Space Flight Center's vector magnetograph for a simple sunspot observed on June 9, 1985. Vector magnetograms were obtained over the wavelength interval of 170 mA redward of line center of the Fe I 5250.22 A spectral line to 170 mA to the blue, in steps of 10 mA. These data were analyzed to produce the variation of the azimuth as a function of wavelength at each pixel over the field of vi ew of the sunspot. At selected locations in the sunspot, curves of the observed variation of azimuth with wavelength were compared with model calculations for the amount of Faraday rotation of the azimuth. From these comparisons we derived the amount of rotation as functions of bo th the magnitude and inclination of the sunspot's field and deduced the ranges of these field values for which Faraday rotation presents a significant problem in observations taken near the center of a spectral line.

Juno Magnetometer Observations in the Earth's Magnetosphere

NASA Astrophysics Data System (ADS)

Connerney, J. E.; Oliversen, R. J.; Espley, J. R.; MacDowall, R. J.; Schnurr, R.; Sheppard, D.; Odom, J.; Lawton, P.; Murphy, S.; Joergensen, J. L.; Joergensen, P. S.; Merayo, J. M.; Denver, T.; Bloxham, J.; Smith, E. J.; Murphy, N.

2013-12-01

The Juno spacecraft enjoyed a close encounter with Earth on October 9, 2013, en route to Jupiter Orbit Insertion (JOI) on July 5, 2016. The Earth Flyby (EFB) provided a unique opportunity for the Juno particles and fields instruments to sample mission relevant environments and exercise operations anticipated for orbital operations at Jupiter, particularly the period of intense activity around perijove. The magnetic field investigation onboard Juno is equipped with two magnetometer sensor suites, located at 10 and 12 m from the spacecraft body at the end of one of the three solar panel wings. Each contains a vector fluxgate magnetometer (FGM) sensor and a pair of co-located non-magnetic star tracker camera heads which provide accurate attitude determination for the FGM sensors. This very capable magnetic observatory sampled the Earth's magnetic field at 64 vector samples/second throughout passage through the Earth's magnetosphere. We present observations of the Earth's magnetic field and magnetosphere obtained throughout the encounter and compare these observations with those of other Earth-orbiting assets, as available, and with particles and fields observations acquired by other Juno instruments operated during EFB.

Earth radiation balance and climate: Why the Moon is the wrong place to observe the Earth

NASA Astrophysics Data System (ADS)

Kandel, Robert S.

1994-06-01

Increasing 'greenhouse' gases in the Earth's atmosphere will perturb the Earth's radiation balance, forcing climate change over coming decades. Climate sensitivity depends critically on cloud-radiation feedback: its evaluation requires continual observation of changing patterns of Earth radiation balance and cloud cover. The Moon is the wrong place for such observations, with many disadvantages compared to an observation system combining platforms in low polar, intermediate-inclination and geostationary orbits. From the Moon, active observations are infeasible; thermal infrared observations require very large instruments to reach spatial resolutions obtained at much lower cost from geostationary or lower orbits. The Earth's polar zones are never well observed from the Moon; other zones are invisible more than half the time. The monthly illumination cycle leads to further bias in radiation budget determinations. The Earth will be a pretty sight from the Earth-side of the Moon, but serious Earth observations will be made elsewhere.

Assessment of the effect of three-dimensional mantle density heterogeneity on earth rotation in tidal frequencies.

PubMed

Liu, Lanbo; Chao, Benjamin F; Sun, Wenke; Kuang, Weijia

2016-11-01

In this paper we report the assessment of the effect of the three-dimensional (3D) density heterogeneity in the mantle on Earth Orientation Parameters (EOP) (i.e., the polar motion, or PM, and the length of day, or LOD) in the tidal frequencies. The 3D mantle density model is estimated based upon a global S-wave velocity tomography model (S16U6L8) and the mineralogical knowledge derived from laboratory experiment. The lateral density variation is referenced against the Preliminary Reference Earth Model (PREM). Using this approach the effects of the heterogeneous mantle density variation in all three tidal frequencies (zonal long periods, tesseral diurnal, and sectorial semidiurnal) are estimated in both PM and LOD. When compared with mass or density perturbations originated on the earth's surface such as the oceanic and barometric changes, the heterogeneous mantle only contributes less than 10% of the total variation in PM and LOD in tidal frequencies. Nevertheless, including the 3D variation of the density in the mantle into account explained a substantial portion of the discrepancy between the observed signals in PM and LOD extracted from the lump-sum values based on continuous space geodetic measurement campaigns (e.g., CONT94) and the computed contribution from ocean tides as predicted by tide models derived from satellite altimetry observations (e.g., TOPEX/Poseidon). In other word, the difference of the two, at all tidal frequencies (long-periods, diurnals, and semi-diurnals) contains contributions of the lateral density heterogeneity of the mantle. Study of the effect of mantle density heterogeneity effect on torque-free earth rotation may provide useful constraints to construct the Reference Earth Model (REM), which is the next major objective in global geophysics research beyond PREM.

The Geolocation model for lunar-based Earth observation

NASA Astrophysics Data System (ADS)

Ding, Yixing; Liu, Guang; Ren, Yuanzhen; Ye, Hanlin; Guo, Huadong; Lv, Mingyang

2016-07-01

In recent years, people are more and more aware of that the earth need to treated as an entirety, and consequently to be observed in a holistic, systematic and multi-scale view. However, the interaction mechanism between the Earth's inner layers and outer layers is still unclear. Therefore, we propose to observe the Earth's inner layers and outer layers instantaneously on the Moon which may be helpful to the studies in climatology, meteorology, seismology, etc. At present, the Moon has been proved to be an irreplaceable platform for Earth's outer layers observation. Meanwhile, some discussions have been made in lunar-based observation of the Earth's inner layers, but the geolocation model of lunar-based observation has not been specified yet. In this paper, we present a geolocation model based on transformation matrix. The model includes six coordinate systems: The telescope coordinate system, the lunar local coordinate system, the lunar-reference coordinate system, the selenocentric inertial coordinate system, the geocentric inertial coordinate system and the geo-reference coordinate system. The parameters, lncluding the position of the Sun, the Earth, the Moon, the libration and the attitude of the Earth, can be acquired from the Ephemeris. By giving an elevation angle and an azimuth angle of the lunar-based telescope, this model links the image pixel to the ground point uniquely.

EarthObserver: Bringing the world to your fingertips

NASA Astrophysics Data System (ADS)

Ryan, W. B.; Goodwillie, A. M.; Coplan, J.; Carbotte, S. M.; Arko, R. A.; Ferrini, V.; O'hara, S. H.; Chan, S.; Bonczkowski, J.; Nitsche, F. O.; Morton, J. J.; McLain, K.; Weissel, R.

2011-12-01

EarthObserver (http://www.earth-observer.org/), developed by the Lamont-Doherty Earth Observatory of Columbia University, brings a wealth of geoscience data to Apple iPad, iPhone and iPod Touch mobile devices. Built around an easy-to-use interface, EarthObserver allows users to explore and visualise a wide range of data sets superimposed upon a detailed base map of land elevations and ocean depths - tapping the screen will instantly return the height or depth at that point. A simple transparency function allows direct comparison of built-in content. Data sets include high-resolution coastal bathymetry of bays, sounds, estuaries, harbors and rivers; geological maps of the US states and world - tapping the screen displays the rock type, and full legends can be viewed; US Topo sheets; and, geophysical content including seafloor crustal age and sediment thickness, earthquake and volcano data, gravity and magnetic anomalies, and plate boundary descriptions. The names of physiographic features are automatically displayed. NASA Visible Earth images along with ocean temperature, salinity and productivity maps and precipitation information expose data sets of interest to the atmospheric, oceanic and biological communities. Natural hazard maps, population information and political boundaries allow users to explore impacts upon society. EarthObserver, so far downloaded by more than 55,000 users, offers myriad ways for educators at all levels to bring research-quality geoscience data into the learning environment, whether for use as an in-class illustration or for extensive exploration of earth sciences data. By using cutting-edge mobile app technology, EarthObserver boosts access to relevant earth science content. The EarthObserver base map is the Global Multi-Resolution Topography digital elevation model (GMRT; http://www.marine-geo.org/portals/gmrt/), also developed at LDEO and updated regularly. It provides land elevations with horizontal resolution as high as 10m for

Earth's rotation irregularities derived from UTIBLI by method of multi-composing of ordinates

NASA Astrophysics Data System (ADS)

Segan, S.; Damjanov, I.; Surlan, B.

Using the method of multi-composing of ordinates we have identified in Earth's rotation a long-periodic term with a period similar to the relaxation time of Chandler nutation. There was not enough information to assess its origin. We demonstrate that the method can be used even in the case when the data time span is comparable to the period of harmonic component.

Book Review: Precession, Nutation, and Wobble of the Earth

NASA Astrophysics Data System (ADS)

Sterken, Christiaan; Dehant, V.; Mathews, P. M.

2016-10-01

This great book describes and explains observational and computational aspects of three apparently tiny changes in the Earth's motion and orientation, viz., precession, nutation, and wobble. The three introductory chapters of this book present fundamental definitions, elementary geodetic theory, and celestial/terrestrial reference systems - including transformations between reference frames. The next chapter on observational techniques describes the principle of accurate measurements of the orientation of the Earth's axis, as obtained from measurements of extra-galactic radio sources using Very Long Baseline Interferometry and GPS observations. Chapter 5 handles precession and nutation of the rigid Earth (i.e., a celestial body that cannot, by definition, deform) and the subsequent chapter takes deformation into consideration, viz., the effect of a centrifugal force caused by a constant-rate rotation that causes the Earth's shape and structure to become ellipsoidal. Deformations caused by external solar-system bodies are discussed in terms of deformability parameters. The next three chapters handle additional complex deviations: non-rigid Earth and more general Earth models, anelastic Earth parameters, and the effects of the fluid layers (i.e., ocean and atmosphere) on Earth rotation. Chapter 10 complements Chapter 7 with refinements that take into account diverse small effects such as the effect of a thermal conductive layer at the top of the core, Core Mantle and Inner Boundary coupling effects on nutation, electromagnetic coupling, and so-called topographic coupling. Chapter 11 covers comparison of observation and theory, and tells us that the present-date precision of the nutation theory is at the level of milliarcseconds in the time domain, and of a tenth of a microsecond in the frequency domain (with some exceptions). This chapter is followed by a 25-page chapter of definitions of equator, equinox, celestial intermediate pole and origin, stellar angle

Value of Earth Observations: NASA Activities with Socioeconomic Analysis

NASA Astrophysics Data System (ADS)

Friedl, L.

2016-12-01

There is greater emphasis internationally on the social and economic benefits that organizations can derive from applications of Earth observations. A growing set of qualitative, anecdotal examples on the uses of Earth observations across a range of sectors can be complemented by the quantitative substantiation of the socioeconomic benefits. In turn, the expanding breadth of environmental data available and the awareness of their beneficial applications to inform decisions can support new products and services. To support these efforts, there are needs to develop impact assessments, populate the literature, and develop familiarity in the Earth science community with the terms, concepts and methods to assess impacts. Within NASA, the Earth Science Division's Applied Sciences Program has initiated and supported numerous activities in recent years to quantify the socioeconomic benefits from Earth observations applications and to build familiarity within the Earth science community. This paper will present an overview of measuring socioeconomic impacts of Earth observations and how the measures can be translated into a value of Earth observation information. It will address key terms, techniques, principles and applications of socioeconomic impact analyses. It will also discuss activities to support analytic techniques, expand the literature, and promote broader skills and capabilities.

Earth Observing System, Conclusions and Recommendations

NASA Technical Reports Server (NTRS)

1984-01-01

The following Earth Observing Systems (E.O.S.) recommendations were suggested: (1) a program must be initiated to ensure that present time series of Earth science data are maintained and continued. (2) A data system that provides easy, integrated, and complete access to past, present, and future data must be developed as soon as possible. (3) A long term research effort must be sustained to study and understand these time series of Earth observations. (4) The E.O.S. should be established as an information system to carry out those aspects of the above recommendations which go beyond existing and currently planned activities. (5) The scientific direction of the E.O.S. should be established and continued through an international scientific steering committee.

Earth rotation derived from occultation records

NASA Astrophysics Data System (ADS)

Sôma, Mitsuru; Tanikawa, Kiyotaka

2016-04-01

We determined the values of the Earth's rotation parameter, ΔT = T T - UT, around AD 500 after confirming that the value of the tidal acceleration, dot{n}, of the lunar motion remained unchanged during the period between ancient times and the present. For determining of ΔT, we used contemporaneous occultations of planets by the Moon. In general, occultation records are not useful. However, there are some records that give us a stringent condition for the range of ΔT. Records of the lunar occultations in AD 503 and AD 513 are such examples. In order to assure the usefulness of this occultation data, we used contemporaneous annular and total solar eclipses, which have not been used in the preceding work. This is the first work in which the lunar occultation data have been used as primary data to determine the value of ΔT together with auxiliary contemporaneous annular and total solar eclipses. Our ΔT value is less than a smoothed value (Stephenson 1997) by at least 450 s. The result is consistent with our earlier results obtained from solar eclipses.

A Dynamic Earth: 50 Years of Observations from Space

NASA Technical Reports Server (NTRS)

Evans, Cynthia A.

2013-01-01

Observations of the surface of the Earth began more than a half century ago with the earliest space missions. The global geopolitical environment at the beginning of the space age fueled advances in rocketry and human exploration, but also advances in remote sensing. At the same time that space-based Earth Observations were developing, global investments in infrastructure that were initiated after World War II accelerated large projects such as the construction of highways, the expansion of cities and suburbs, the damming of rivers, and the growth of big agriculture. These developments have transformed the Earth s surface at unprecedented rates. Today, we have a remarkable library of 50 years of observations of the Earth taken by satellite-based sensors and astronauts, and these images and observations provide insight into the workings of the Earth as a system. In addition, these observations record the footprints of human activities around the world, and illustrate how our activities contribute to the changing face of the Earth. Starting with the iconic "Blue Marble" image of the whole Earth taken by Apollo astronauts, we will review a timeline of observations of our planet as viewed from space.

The NASA Space Shuttle Earth Observations Office

NASA Technical Reports Server (NTRS)

Helfert, Michael R.; Wood, Charles A.

1989-01-01

The NASA Space Shuttle Earth Observations Office conducts astronaut training in earth observations, provides orbital documentation for acquisition of data and catalogs, and analyzes the astronaut handheld photography upon the return of Space Shuttle missions. This paper provides backgrounds on these functions and outlines the data constraints, organization, formats, and modes of access within the public domain.

Secular rotational motions and the mechanical structure of a dynamical viscoelastic earth

NASA Technical Reports Server (NTRS)

Yuen, D. A.; Sabadini, R.

1984-01-01

A survey is presented of analytical methods for computing the linear responses of the rotational axis of a layered viscoelastic earth to surface loading. Theoretical research in this area is first summarized, and the differences between the mechanical boundary conditions to be applied at the interface separating the upper and lower mantles for an adiabatically and chemically stratified mantle are discussed. Some examples of polar wander and secular variation of the spin rate from glacial excitation are presented for various types of chemical and viscosity stratifications. The effects of an artificial density jump at the base of the lithosphere in models are examined, and certain issues concerning the fluid tidal Love number for different types of density stratification are addressed. The meaning of effective plate thickness over geological time scales for rotational dynamics is discussed.

When the Earth's Inner Core Shuffles

NASA Astrophysics Data System (ADS)

Tkalcic, H.; Young, M. K.; Bodin, T.; Ngo, S.; Sambridge, M.

2011-12-01

Shuffling is a tribal dance recently adapted by teenagers as a street dance. In one of the most popular moves, the so-called "Running Man", a stomp forward on one foot, shifted without being lifted from the ground, is followed by a change of position backwards on the same foot. Here, we present strong observational evidence from a newly observed collection of earthquake doublets that the Earth's inner core "shuffles" exhibiting both prograde and retrograde rotation in the reference frame of the mantle. This discovery is significant on several levels. First, the observed pattern consists of intermittent intervals of quasi-locked and differentially rotating inner core with respect to the Earth's mantle. This means that the angular alignment of the inner core and mantle oscillates in time over the past five decades. Jolting temporal changes are revealed, indicating that during the excursions from the quasi-locked state, the Earth's inner core can rotate both faster and slower than the rest of the planet, thus exhibiting both eastward and westward rotation. According to our results, a short time interval (on the order of one to two years) is needed for the inner core to accelerate to a differential rotation rate of several degrees per year, and typically a slightly longer time is needed to decelerate down to a negligibly small differential rotation rate. These time scales are in agreement with experimental spin-up times obtained when the magnetic torque alone is used to accelerate the inner core. Second, when we integrate the rotation rate over different time intervals, it is possible to explain discrepancies between the body wave and normal modes results for the rate of the inner core differential rotation found by previous authors. We show that the integrated shift in angular alignment and average rotation rates (previously determined to be constant) in normal mode studies are much smaller that those for the body waves. The repeating earthquakes from the South

Fluid signatures of rotational discontinuities at Earth's magnetopause

NASA Technical Reports Server (NTRS)

Scudder, J. D.

1983-01-01

Fluid signatures in the MHD approximation at rotational discontinuities (RD) of finite width called rotational shear layers (RSL) are examined for general flow and magnetic geometries. Analytical and geometrical arguments illustrate that the fluid speed can either go up or down across an RSL for a fixed normal mass flux. The speed profile may or may not be monotonic depending on the boundary conditions. The flow velocity may or may not be field aligned or ""jetting'' as a result of traversing the RSL. In general, significant ""convection'' is expected in the layer. The observable signatures of (MHD) RSL's depend on 7 (boundary condition) parameters are (1) the mass density, (2 to 5) the incident normal and transverse components of the magnetic field and fluid velocity, (6) the angle epsilon between the incident tangential flow velocity and tangential magnetic field, and (7) the size of the magnetic angular rotation implemented by the layer delta phi.

Pull vs. Push: How OmniEarth Delivers Better Earth Observation Information to Subscribers

NASA Astrophysics Data System (ADS)

Fish, C.; Slagowski, S.; Dyrud, L.; Fentzke, J.; Hargis, B.; Steerman, M.

2015-04-01

Until very recently, the commercialization of Earth observation systems has largely occurred in two ways: either through the detuning of government satellites or the repurposing of NASA (or other science) data for commercial use. However, the convergence of cloud computing and low-cost satellites is enabling Earth observation companies to tailor observation data to specific markets. Now, underserved constituencies, such as agriculture and energy, can tap into Earth observation data that is provided at a cadence, resolution and cost that can have a real impact to their bottom line. To connect with these markets, OmniEarth fuses data from a variety of sources, synthesizes it into useful and valuable business information, and delivers it to customers via web or mobile interfaces. The "secret sauce" is no longer about having the highest resolution imagery, but rather it is about using that imagery - in conjunction with a number of other sources - to solve complex problems that require timely and contextual information about our dynamic and changing planet. OmniEarth improves subscribers' ability to visualize the world around them by enhancing their ability to see, analyze, and react to change in real time through a solutions-as-a-service platform.

Observation of the nearly diurnal resonance of the earth using a laser strainmeter

NASA Technical Reports Server (NTRS)

Levine, J.

1978-01-01

The response of the Earth to the diurnal and semidiurnal tidal excitations was studied. Results show that there is significant structure in the response of the earth to tidal excitations near one cycle/sidereal day. This structure agrees with the resonance behavior predicted from the calculations of the forced elasticgravitational response of an elliptical, rotating earth with a liquid outer core. The data is used to test for possible preferred frames and spatial anisotropies. Upper bounds on the parameterized post-Newtonian (PPN) parameters were examined.

Scientific Contributions to GEO Global Earth Observation Priorities

NASA Astrophysics Data System (ADS)

Friedl, L.; Ledrew, E.

2009-12-01

Numerous counties and non-governmental organizations have produced documents, held workshops, and published reports in the past decade that identify Earth observation needs to meet their particular objectives. The Group on Earth Observations (GEO) has conducted a review of these documents, workshops, and reports to identify the priority observations common to many societal benefit areas. GEO has made a concerted effort to include materials from a broad range of user types, including scientific researchers, resource managers, and policy makers. GEO has also sought an international breadth in the materials reviewed, including observation priorities from developing countries. The activity will help GEO optimize the observations in GEOSS that are most likely to provide societal benefits, and GEO members will use the results of this meta-analysis to support investment decisions. The Earth observations in GEOSS serve scientific research and applications endeavors. As a primary user of ground-based, airborne, in situ, and space-based observations of the Earth, the scientific community has a significant voice and vested interest in the observations offered through GEOSS. Furthermore, the science and technology community will have opportunities to identify critical scientific/technological advances needed to produce any observations that are needed yet not currently available. In this paper, we will discuss this GEO effort to identify Earth observations priorities. We will present initial findings for some societal benefit areas and the overall meta-analysis. We will also discuss possible roles for the science and technology community to contribute to those priorities, such as scientific advances needed to achieve the observations or to realize societal benefits from the observations.

A normal mode treatment of semi-diurnal body tides on an aspherical, rotating and anelastic Earth

NASA Astrophysics Data System (ADS)

Lau, Harriet C. P.; Yang, Hsin-Ying; Tromp, Jeroen; Mitrovica, Jerry X.; Latychev, Konstantin; Al-Attar, David

2015-08-01

Normal mode treatments of the Earth's body tide response were developed in the 1980s to account for the effects of Earth rotation, ellipticity, anelasticity and resonant excitation within the diurnal band. Recent space-geodetic measurements of the Earth's crustal displacement in response to luni-solar tidal forcings have revealed geographical variations that are indicative of aspherical deep mantle structure, thus providing a novel data set for constraining deep mantle elastic and density structure. In light of this, we make use of advances in seismic free oscillation literature to develop a new, generalized normal mode theory for the tidal response within the semi-diurnal and long-period tidal band. Our theory involves a perturbation method that permits an efficient calculation of the impact of aspherical structure on the tidal response. In addition, we introduce a normal mode treatment of anelasticity that is distinct from both earlier work in body tides and the approach adopted in free oscillation seismology. We present several simple numerical applications of the new theory. First, we compute the tidal response of a spherically symmetric, non-rotating, elastic and isotropic Earth model and demonstrate that our predictions match those based on standard Love number theory. Second, we compute perturbations to this response associated with mantle anelasticity and demonstrate that the usual set of seismic modes adopted for this purpose must be augmented by a family of relaxation modes to accurately capture the full effect of anelasticity on the body tide response. Finally, we explore aspherical effects including rotation and we benchmark results from several illustrative case studies of aspherical Earth structure against independent finite-volume numerical calculations of the semi-diurnal body tide response. These tests confirm the accuracy of the normal mode methodology to at least the level of numerical error in the finite-volume predictions. They also demonstrate

Earth Observing System (EOS) advanced altimetry

NASA Technical Reports Server (NTRS)

Parsons, C. L.; Walsh, E. J.

1988-01-01

In the post-TOPEX era, satellite radar altimeters will be developed with the capability of measuring the earth's surface topography over a wide swath of coverage, rather than just at the satellite's nadir. The identification of potential spacecraft flight missions in the future was studied. The best opportunity was found to be the Earth Observing System (EOS). It is felt that an instrument system that has a broad appeal to the earth sciences community stands a much better chance of being selected as an EOS instrument. Consequently, the Topography and Rain Radar Imager (TARRI) will be proposed as a system that has the capability to profile the Earth's topography regardless of the surface type. The horizontal and height resolutions of interest are obviously significantly different over land, ice, and water; but, the use of radar to provide an all-weather observation capability is applicable to the whole earth. The scientific guidance for the design and development of this instrument and the eventual scientific utilization of the data produced by the TARRI will be provided by seven science teams. The teams are formed around scientific disciplines and are titled: Geology/Geophysics, Hydrology/Rain, Oceanography, Ice/Snow, Geodesy/Orbit/Attitude, Cartography, and Surface Properties/Techniques.

International program for Earth observations

NASA Technical Reports Server (NTRS)

1990-01-01

During the 1990 summer session of the International Space University, graduate students of many different countries and with various academic backgrounds carried out a design project that focused on how to meet the most pressing environmental information requirements of the 1990's. The International Program for Earth Observations (IPEO) is the result of the students labor. The IPEO report examines the legal and institutional, scientific, engineering and systems, financial and economic, and market development approaches needed to improve international earth observations and information systems to deal with environmental issues of global importance. The IPEO scenario is based on the production of a group of lightweight satellites to be used in global remote sensing programs. The design and function of the satellite is described in detail.

Earth Observation

NASA Image and Video Library

2011-07-06

ISS028-E-014782 (6 July 2011) --- The Shoemaker (formerly Teague) Impact Structure, located in Western Australia in a drainage basin south of the Waldburg Range, presents an other-worldly appearance in this detailed photograph recorded from onboard the International Space Station on July 6. The Shoemaker impact site is approximately 30 kilometers in diameter, and is clearly defined by concentric ring structures formed in sedimentary rocks (brown to dark brown, image center) that were deformed by the impact event approximately 1630 million years ago, according to the Earth Impact Database. Several saline and ephemeral lakes?Nabberu, Teague, Shoemaker, and numerous smaller ponds?occupy the land surface between the concentric ring structures. Differences in color result from both water depth and suspended sediments, with some bright salt crusts visible around the edges of smaller ponds (image center The Teague Impact Structure was renamed Shoemaker in honor of the late Dr. Eugene M. Shoemaker, a pioneer in the field of impact crater studies and planetary geology, and founder of the Astrogeology Branch of the United States Geological Survey. The image was recorded with a digital still camera using a 200 mm lens, and is provided by the ISS Crew Earth Observations experiment and Image Science & Analysis Laboratory, Johnson Space Center.

Earth Observations

NASA Image and Video Library

2010-09-11

ISS024-E-014233 (11 Sept. 2010) --- A smoke plume near the northern Caspian Sea, Kazakhstan is featured in this image photographed by an Expedition 24 crew member on the International Space Station. This broad view of the north coast of the Caspian Sea shows a smoke plume (left) and two river deltas (bottom and lower right). The larger delta is that of the Volga River which appears prominently here in sunglint (light reflected off a water surface back towards the observer), and the smaller less prominent delta is that of the Ural River. Wide angle, oblique views ? taken looking outward at an angle, rather than straight down towards Earth ? such as this give an excellent impression of how crew members onboard the space station view Earth. For a sense of scale, the Caucasus Mts. (across the Caspian, top right) are approximately 1,100 kilometers to the southwest of the International Space Station?s nadir point location ? the point on Earth directly underneath the spacecraft ? at the time this image was taken. The smoke plume appears to be sourced in the dark-toned coastal marsh vegetation along the outer fringe of the Ural River delta, rather than in a city or at some oil storage facility. Although even small fires produce plumes that are long and bright and thus easily visible from space, the density of the smoke in this plume, and its 350-kilometer length across the entire north lobe of the Caspian Sea, suggest it was a significant fire. The smoke was thick enough nearer the source to cast shadows on the sea surface below. Lines mark three separate pulses of smoke, the most recent, nearest the source, extending directly south away from the coastline (lower left). With time, plumes become progressively more diffuse. The oldest pulse appears to be the thinnest, casting no obvious shadows (center left).

Adiabatic decay of internal solitons due to Earth's rotation within the framework of the Gardner-Ostrovsky equation

NASA Astrophysics Data System (ADS)

Obregon, Maria; Raj, Nawin; Stepanyants, Yury

2018-03-01

The adiabatic decay of different types of internal wave solitons caused by the Earth's rotation is studied within the framework of the Gardner-Ostrovsky equation. The governing equation describing such processes includes quadratic and cubic nonlinear terms, as well as the Boussinesq and Coriolis dispersions: (ut + c ux + α u ux + α1 u2 ux + β uxxx)x = γ u. It is shown that at the early stage of evolution solitons gradually decay under the influence of weak Earth's rotation described by the parameter γ. The characteristic decay time is derived for different types of solitons for positive and negative coefficients of cubic nonlinearity α1 (both signs of that parameter may occur in the oceans). The coefficient of quadratic nonlinearity α determines only a polarity of solitary wave when α1 < 0 or the asymmetry of solitary waves of opposite polarity when α1 > 0. It is found that the adiabatic theory describes well the decay of solitons having bell-shaped profiles. In contrast to that, large amplitude table-top solitons, which can exist when α1 is negative, are structurally unstable. Under the influence of Earth's rotation, they transfer first to the bell-shaped solitons, which decay then adiabatically. Estimates of the characteristic decay time of internal solitons are presented for the real oceanographic conditions.

Direct observation of students during clerkship rotations: a multiyear descriptive study.

PubMed

Howley, Lisa D; Wilson, William G

2004-03-01

To determine how often students report that they are observed while performing physical examinations and taking histories during clerkship rotations. From 1999-2001, 397 students at the University of Virginia School of Medicine were asked at the end of their third year to report the number of times they had been observed by a resident or faculty member while taking histories and performing physical examinations on six rotations. Three hundred and forty-five students (87%) returned the survey instrument; of these, 322 (81%) returned instruments with complete information. On average, the majority reported that they had never been observed by a faculty member while taking a history (51%), performing a focused physical examination (54%), or a complete physical examination (81%). The majority (60%) reported that they had never been observed by a resident while performing a complete physical examination. Faculty observations occurred most frequently during the four-week family medicine rotation and least frequently during the 12-week surgery rotation. The length of the clerkship rotation was inversely related to the number of reported observations, chi(2) (5, n = 295) = 127.85, p <.000. Although alternative assessments of clinical skills are becoming more common in medical education, faculty ratings based on direct observation are still prominent. The data in this study reflect that these observations may actually be occurring quite infrequently, if at all. Decreasing the evaluative weight of faculty and resident ratings during the clerkship rotation may be necessary. Otherwise, efforts should be made to increase the validity of these ratings.

Optical data communication for Earth observation satellite systems

NASA Astrophysics Data System (ADS)

Fischer, J.; Loecherbach, E.

1991-10-01

The current development status of optical communication engineering in comparison to the conventional microwave systems and the different configurations of the optical data communication for Earth observation satellite systems are described. An outlook to future optical communication satellite systems is given. During the last decade Earth observation became more and more important for the extension of the knowledge about our planet and the human influence on nature. Today pictures taken by satellites are used, for example, to discover mineral resources or to predict harvest, crops, climate, and environment variations and their influence on the population. A new and up to date application for Earth observation satellites can be the verification of disarmament arrangements and the control of crises areas. To solve these tasks a system of Earth observing satellites with sensors tailored to the envisaged mission is necessary. Besides these low Earth orbiting satellites, a global Earth observation system consists of at least two data relay satellites. The communication between the satellites will be established via Inter-Satellite Links (ISL) and Inter-Orbit Links (IOL). On these links, bitrates up to 1 Gbit/s must be taken into account. Due to the increasing scarcity of suitable frequencies, higher carrier frequencies must probably be considered, and possible interference with terrestrial radio relay systems are two main problems for a realization in microwave technique. One important step to tackle these problems is the use of optical frequencies for IOL's and ISL's.

Commercial Earth Observation

NASA Technical Reports Server (NTRS)

1995-01-01

Through the Earth Observation Commercial Applications Program (EOCAP) at Stennis Space Center, Applied Analysis, Inc. developed a new tool for analyzing remotely sensed data. The Applied Analysis Spectral Analytical Process (AASAP) detects or classifies objects smaller than a pixel and removes the background. This significantly enhances the discrimination among surface features in imagery. ERDAS, Inc. offers the system as a modular addition to its ERDAS IMAGINE software package for remote sensing applications. EOCAP is a government/industry cooperative program designed to encourage commercial applications of remote sensing. Projects can run three years or more and funding is shared by NASA and the private sector participant. Through the Earth Observation Commercial Applications Program (EOCAP), Ocean and Coastal Environmental Sensing (OCENS) developed SeaStation for marine users. SeaStation is a low-cost, portable, shipboard satellite groundstation integrated with vessel catch and product monitoring software. Linked to the Global Positioning System, SeaStation provides real time relationships between vessel position and data such as sea surface temperature, weather conditions and ice edge location. This allows the user to increase fishing productivity and improve vessel safety. EOCAP is a government/industry cooperative program designed to encourage commercial applications of remote sensing. Projects can run three years or more and funding is shared by NASA and the private sector participant.

Earth observation image data format

NASA Technical Reports Server (NTRS)

Sos, J. Y.

1976-01-01

A flexible format for computer compatable tape (CCT) containing multispectral earth observation sensor data is described. The driving functions which comprise the data format requirements are summarized and general data format guidelines are discussed.

Decreasing of axial angular momentum of oceanic both fluid continental masses and its contribution to non-tidal acceleration of rotation of the Earth

NASA Astrophysics Data System (ADS)

Barkin, Yu. V.

2009-04-01

Modeling constructions have shown, that a variation of geopotential coefficients, since the second harmonic, are determined basically by redistributions of fluid masses in the top shells of the Earth [1]. Only on a variation of coefficients of the first harmonic essential influence renders displacement of the centre of mass in the basic mantle reference system. By the similar redistribution of masses it is obviously possible to estimate a variation of the axial moment of inertia of the full Earth, including an atmosphere and ocean, on a value of variation of coefficient of the second zonal harmonic of geopotential: Ċ• C = 2˙J2•(3I) (I = 0.3307is a dimensionless polar moment of inertia of the Earth, C is the polar moment of inertia of the Earth). According to satellite observations ˙ J2 = (2.7 ± 0.4) × 10-11 1/yr[2] and, hence, we obtain an estimation Ċ•C = -(5.4 ± 0.8) × 10-11 1/yr. We use this value for an establishment of the new phenomenon - acceleration of return superrotation of fluids in western direction. For what we shall take advantage of known estimations of secular non-tidal acceleration of rotation of the rigid Earth: ˙?•? = (6.9± 1.2) × 10-11 1/yr (corresponding variation LOD makes -0.6 ± 0.1 ms/cy) [3] and variations of angular velocity of axial rotation of the Earth because of secular increase of a polar atmosphere angular moment: -0.56 ms/cy[4]. On Salstein's data for 1970 - 2002 a positive trend of polar component of the angular momentum really exists. Corresponding reduction of duration of day is characterized by velocity-0.525 ms/cy. First of the given values has been obtained by results of observations of solar eclipses over last 2500. And the second value has been obtained on the data on variations of specified component of the angular momentum for last 60 years. Thus, in present epoch an acceleration of superrotation of an atmosphere is observed. Which results in delay of rotation of the Earth with relative

The Common Framework for Earth Observation Data

NASA Astrophysics Data System (ADS)

Gallo, J.; Stryker, T. S.; Sherman, R.

2016-12-01

Each year, the Federal government records petabytes of data about our home planet. That massive amount of data in turn provides enormous benefits to society through weather reports, agricultural forecasts, air and water quality warnings, and countless other applications. To maximize the ease of transforming the data into useful information for research and for public services, the U.S. Group on Earth Observations released the first Common Framework for Earth Observation Data in March 2016. The Common Framework recommends practices for Federal agencies to adopt in order to improve the ability of all users to discover, access, and use Federal Earth observations data. The U.S. Government is committed to making data from civil Earth observation assets freely available to all users. Building on the Administration's commitment to promoting open data, open science, and open government, the Common Framework goes beyond removing financial barriers to data access, and attempts to minimize the technical impediments that limit data utility. While Earth observation systems typically collect data for a specific purpose, these data are often also useful in applications unforeseen during development of the systems. Managing and preserving these data with a common approach makes it easier for a wide range of users to find, evaluate, understand, and utilize the data, which in turn leads to the development of a wide range of innovative applications. The Common Framework provides Federal agencies with a recommended set of standards and practices to follow in order to achieve this goal. Federal agencies can follow these best practices as they develop new observing systems or modernize their existing collections of data. This presentation will give a brief on the context and content of the Common Framework, along with future directions for implementation and keeping its recommendations up-to-date with developing technology.

The rotation of the Sun: Observations at Stanford. [using the Doppler effect

NASA Technical Reports Server (NTRS)

Scherrer, J. M.; Wilcox, J. M.; Svalgaard, L.

1980-01-01

Daily observations of the photospheric rotation rate using the Doppler effect made at the Stanford Solar Observatory since May 1976 are analyzed. Results show that these observations show no daily or long period variations in the rotation rate that exceed the observational error of about one percent. The average rotation rate is the same as that of the sunspot and the large-scale magnetic field structures.

Earth Rotation Parameter Solutions using BDS and GPS Data from MEGX Network

NASA Astrophysics Data System (ADS)

Xu, Tianhe; Yu, Sumei; Li, Jiajing; He, Kaifei

2014-05-01

Earth rotation parameters (ERPs) are necessary parameters to achieve mutual transformation of the celestial reference frame and earth-fix reference frame. They are very important for satellite precise orbit determination (POD), high-precision space navigation and positioning. In this paper, the determination of ERPs including polar motion (PM), polar motion rate (PMR) and length of day (LOD) are presented using BDS and GPS data of June 2013 from MEGX network based on least square (LS) estimation with constraint condition. BDS and GPS data of 16 co-location stations from MEGX network are the first time used to estimate the ERPs. The results show that the RMSs of x and y component errors of PM and PM rate are about 0.9 mas, 1.0 mas, 0.2 mas/d and 0.3 mas/d respectively using BDS data. The RMS of LOD is about 0.03 ms/d using BDS data. The RMSs of x and y component errors of PM and PM rate are about 0.2 mas, 0.2 mas/d respectively using GPS data. The RMS of LOD is about 0.02 ms/d using GPS data. The optimal relative weight is determined by using variance component estimation when combining BDS and GPS data. The accuracy improvements of adding BDS data is between 8% to 20% for PM and PM rate. There is no obvious improvement in LOD when BDS data is involved. System biases between BDS and GPS are also resolved per station. They are very stable from day to day with the average accuracy of about 20 cm. Keywords: Earth rotation parameter; International GNSS Service; polar motion; length of day; least square with constraint condition Acknowledgments: This work was supported by Natural Science Foundation of China (41174008) and the Foundation for the Author of National Excellent Doctoral Dissertation of China (2007B51) .

Attitude Accuracy Study for the Earth Observing System (EOS) AM-1 Spacecraft

NASA Technical Reports Server (NTRS)

Lesikar, James D., II; Garrick, Joseph C.

1996-01-01

Earth Observing System (EOS) spacecraft will take measurements of the Earth's clouds, oceans, atmosphere, land, and radiation balance. These EOS spacecraft are part of the National Aeronautics and Space Administration's Mission to Planet Earth, and consist of several series of satellites, with each series specializing in a particular class of observations. This paper focuses on the EOS AM-1 spacecraft, which is the first of three satellites constituting the EOS AM series (morning equatorial crossing) and the initial spacecraft of the EOS program. EOS AM-1 has a stringent onboard attitude knowledge requirement, of 36/41/44 arc seconds (3 sigma) in yaw/roll/pitch, respectively. During normal mission operations, attitude is determined onboard using an extended Kalman sequential filter via measurements from two charge coupled device (CCD) star trackers, one Fine Sun Sensor, and an Inertial Rate Unit. The attitude determination error analysis system (ADEAS) was used to model the spacecraft and mission profile, and in a worst case scenario with only one star tracker in operation, the attitude uncertainty was 9.7/ll.5/12.2 arc seconds (3 sigma) in yaw/roll/pitch. The quoted result assumed the spacecraft was in nominal attitude, using only the 1-rotation per orbit motion of the spacecraft about the pitch axis for calibration of the gyro biases. Deviations from the nominal attitude would show greater attitude uncertainties, unless calibration maneuvers which roll and/or yaw the spacecraft have been performed. This permits computation of the gyro misalignments, and the attitude knowledge requirement would remain satisfied.

Optical MEMS for earth observation payloads

NASA Astrophysics Data System (ADS)

Rodrigues, B.; Lobb, D. R.; Freire, M.

2017-11-01

An ESA study has been taken by Lusospace Ltd and Surrey Satellite Techonoly Ltd (SSTL) into the use of optical Micro Eletro-Mechanical Systems (MEMS) for earth Observation. A review and analysis was undertaken of the Micro-Optical Electro-Mechanical Systems (MOEMS) available in the market with potential application in systems for Earth Observation. A summary of this review will be presented. Following the review two space-instrument design concepts were selected for more detailed analysis. The first was the use of a MEMS device to remove cloud from Earth images. The concept is potentially of interest for any mission using imaging spectrometers. A spectrometer concept was selected and detailed design aspects and benefits evaluated. The second concept developed uses MEMS devices to control the width of entrance slits of spectrometers, to provide variable spectral resolution. This paper will present a summary of the results of the study.

Lightcurve Analysis for Two Near-Earth Asteroids Eclipsed by the Earth's Shadow

NASA Astrophysics Data System (ADS)

Birtwhistle, Peter

2018-07-01

Photometry was obtained from Great Shefford Observatory of near-Earth asteroids 2012 XE54 in 2012 and 2016 VA in 2016 during close approaches. A superfast rotation period has been determined for 2012 XE54 and H-G magnitude system coefficients have been estimated for 2016 VA. While under observation, 2012 XE54 underwent a deep penumbral eclipse by the Earth's shadow and 2016 VA also experienced a total eclipse by the Earth's shadow. The dimming due to the eclipses is modeled taking into account solar limb darkening.

CONSTRUCTION OF AN EARTH MODEL: ANALYSIS OF EXOPLANET LIGHT CURVES AND MAPPING THE NEXT EARTH WITH THE NEW WORLDS OBSERVER

DOE Office of Scientific and Technical Information (OSTI.GOV)

Oakley, P. H. H.; Cash, W.

2009-08-01

The orbital light curve of a terrestrial exoplanet will likely contain valuable information about the surface and atmospheric features of the planet, both in its overall shape and hourly variations. We have constructed an empirically based code capable of simulating observations of the Earth from any orientation, at any time of year with continuously updated cloud and snow coverage with a New Worlds Observatory. By simulating these observations over a full orbital revolution at a distance of 10 pc we determine that the detection of an obliquity or seasonal terrain change is possible at low inclinations. In agreement with othermore » studies, a 4 m New Worlds Observer can accurately determine the rotation rate of the planet at a success rate from {approx}30% to 80% with only 5 days of observations depending on the signal to noise of the observations. We also attempt simple inversions of these diurnal light curves to sketch a map of the reflecting planet's surface features. This mapping technique is only successful with highly favorable systems and in particular requires that the cloud coverage must be lower than the Earth's average. Our test case of a 2 M {sub +} planet at 7 pc distance with low exo-zodiacal light and 25% cloud coverage produced crude, but successful results. Additionally, with these highly favorable systems NWO may be able to discern the presence of liquid surface water (or other smooth surfaces) though it requires a complex detection available only at crescent phases in high inclination systems.« less

Earth Observation

NASA Image and Video Library

2014-06-01

ISS040-E-006327 (1 June 2014) --- A portion of International Space Station solar array panels and Earth?s horizon are featured in this image photographed by an Expedition 40 crew member on the space station.

Analysis of Critical Earth Observation Priorities for Societal Benefit

NASA Astrophysics Data System (ADS)

Zell, E. R.; Huff, A. K.; Carpenter, A. T.; Friedl, L.

2011-12-01

To ensure that appropriate near real-time (NRT) and historical Earth observation data are available to benefit society and meet end-user needs, the Group on Earth Observations (GEO) sponsored a multi-disciplinary study to identify a set of critical and common Earth observations associated with 9 Societal Benefit Areas (SBAs): Agriculture, Biodiversity, Climate, Disasters, Ecosystems, Energy, Health, Water, and Weather. GEO is an intergovernmental organization working to improve the availability, access, and use of Earth observations to benefit society through a Global Earth Observation System of Systems (GEOSS). The study, overseen by the GEO User Interface Committee, focused on the "demand" side of Earth observation needs: which users need what types of data, and when? The methodology for the study was a meta-analysis of over 1,700 publicly available documents addressing Earth observation user priorities, under the guidance of expert advisors from around the world. The result was a ranking of 146 Earth observation parameters that are critical and common to multiple SBAs, based on an ensemble of 4 statistically robust methods. Within the results, key details emerged on NRT observations needed to serve a broad community of users. The NRT observation priorities include meteorological parameters, vegetation indices, land cover and soil property observations, water body and snow cover properties, and atmospheric composition. The results of the study and examples of NRT applications will be presented. The applications are as diverse as the list of priority parameters. For example, NRT meteorological and soil moisture information can support monitoring and forecasting for more than 25 infectious diseases, including epidemic diseases, such as malaria, and diseases of major concern in the U.S., such as Lyme disease. Quickly evolving events that impact forests, such as fires and insect outbreaks, can be monitored and forecasted with a combination of vegetation indices, fuel

Catalogs of Space Shuttle earth observations photography

NASA Technical Reports Server (NTRS)

Lulla, Kamlesh; Helfert, Michael

1990-01-01

A review is presented of postflight cataloging and indexing activities of mission data obtained from Space Shuttle earth observations photography. Each Space Shuttle mission acquires 1300-4400 photographs of the earth that are reviewed and interpreted by a team of photointerpreters and cataloging specialists. Every photograph's manual and electronic set of plots is compared for accuracy of its locational coordinates. This cataloging activity is a critical and principal part of postflight activity and ensures that the database is accurate, updated and consequently made meaningful for further utilization in the applications and research communities. A final product in the form of a Catalog of Space Shuttle Earth Observations Handheld Photography is published for users of this database.

Advanced Earth Observation System Instrumentation Study (aeosis)

NASA Technical Reports Server (NTRS)

White, R.; Grant, F.; Malchow, H.; Walker, B.

1975-01-01

Various types of measurements were studied for estimating the orbit and/or attitude of an Earth Observation Satellite. An investigation was made into the use of known ground targets in the earth sensor imagery, in combination with onboard star sightings and/or range and range rate measurements by ground tracking stations or tracking satellites (TDRSS), to estimate satellite attitude, orbital ephemeris, and gyro bias drift. Generalized measurement equations were derived for star measurements with a particular type of star tracker, and for landmark measurements with a multispectral scanner being proposed for an advanced Earth Observation Satellite. The use of infra-red horizon measurements to estimate the attitude and gyro bias drift of a geosynchronous satellite was explored.

Planet Within a Planet: Rotation of the Inner Core of Earth

PubMed

Su; Dziewonski; Jeanloz

1996-12-13

The time dependence of the orientation of Earth's inner core relative to the mantle was determined using a recently discovered 10-degree tilt in the axis of symmetry of the inner core's seismic-velocity anisotropy. Two methods of analyzing travel-time variations for rays traversing the inner core, on the basis of 29 years of data from the International Seismological Centre (1964-1992), reveal that the inner core appears to rotate about 3 degrees per year faster than the mantle. An anomalous variation in inner-core orientation from 1969 to 1973 coincides in time with a sudden change ("jerk") in the geomagnetic field.

Modeling the Conducting Stably-Stratified Layer of the Earth's Core

NASA Astrophysics Data System (ADS)

Petitdemange, L.; Philidet, J.; Gissinger, C.

2017-12-01

Observations of the Earth magnetic field as well as recent theoretical works tend to show that the Earth's outer liquid core is mostly comprised of a convective zone in which the Earth's magnetic field is generated - likely by dynamo action -, but also features a thin, stably stratified layer at the top of the core.We carry out direct numerical simulations by modeling this thin layer as an axisymmetric spherical Couette flow for a stably stratified fluid embedded in a dipolar magnetic field. The dynamo region is modeled by a conducting inner core rotating slightly faster than the insulating mantle due to magnetic torques acting on it, such that a weak differential rotation (low Rossby limit) can develop in the stably stratified layer.In the case of a non-stratified fluid, the combined action of the differential rotation and the magnetic field leads to the well known regime of `super-rotation', in which the fluid rotates faster than the inner core. Whereas in the classical case, this super-rotation is known to vanish in the magnetostrophic limit, we show here that the fluid stratification significantly extends the magnitude of the super-rotation, keeping this phenomenon relevant for the Earth core. Finally, we study how the shear layers generated by this new state might give birth to magnetohydrodynamic instabilities or waves impacting the secular variations or jerks of the Earth's magnetic field.

An Evolving Model for Capacity Building with Earth Observation Imagery

NASA Astrophysics Data System (ADS)

Sylak-Glassman, E. J.

2015-12-01

For the first forty years of Earth observation satellite imagery, all imagery was collected by civilian or military governmental satellites. Over this timeframe, countries without observation satellite capabilities had very limited access to Earth observation data or imagery. In response to the limited access to Earth observation systems, capacity building efforts were focused on satellite manufacturing. Wood and Weigel (2012) describe the evolution of satellite programs in developing countries with a technology ladder. A country moves up the ladder as they move from producing satellites with training services to building satellites locally. While the ladder model may be appropriate if the goal is to develop autonomous satellite manufacturing capability, in the realm of Earth observation, the goal is generally to derive societal benefit from the use of Earth observation-derived information. In this case, the model for developing Earth observation capacity is more appropriately described by a hub-and-spoke model in which the use of Earth observation imagery is the "hub," and the "spokes" describe the various paths to achieving that imagery: the building of a satellite (either independently or with assistance), the purchase of a satellite, participation in a constellation of satellites, and the use of freely available or purchased satellite imagery. We discuss the different capacity-building activities that are conducted in each of these pathways, such as the "Know-How Transfer and Training" program developed by Surrey Satellite Technology Ltd. , Earth observation imagery training courses run by SERVIR in developing countries, and the use of national or regional remote sensing centers (such as those in Morocco, Malaysia, and Kenya) to disseminate imagery and training. In addition, we explore the factors that determine through which "spoke" a country arrives at the ability to use Earth observation imagery, and discuss best practices for achieving the capability to use

Digest of NASA earth observation sensors

NASA Technical Reports Server (NTRS)

Drummond, R. R.

1972-01-01

A digest of technical characteristics of remote sensors and supporting technological experiments uniquely developed under NASA Applications Programs for Earth Observation Flight Missions is presented. Included are camera systems, sounders, interferometers, communications and experiments. In the text, these are grouped by types, such as television and photographic cameras, lasers and radars, radiometers, spectrometers, technology experiments, and transponder technology experiments. Coverage of the brief history of development extends from the first successful earth observation sensor aboard Explorer 7 in October, 1959, through the latest funded and flight-approved sensors under development as of October 1, 1972. A standard resume format is employed to normalize and mechanize the information presented.

ESA's Earth Observation Programmes in the Changing Anthropocene

NASA Astrophysics Data System (ADS)

Liebig, Volker

2016-07-01

The intervention will present ESA's Earth Observation programmes and their relevance to studying the anthropocene. ESA's Earth observation missions are mainly grouped into three categories: The Sentinel satellites in the context of the European Copernicus Programme, the scientific Earth Explorers and the meteorological missions. Developments, applications and scientific results for the different mission types will be addressed, along with overall trends and strategies. The Earth Explorers, who form the science and research element of ESA's Living Planet Programme, focus on the atmosphere, biosphere, hydrosphere, cryosphere and Earth's interior. The Earth Explorers also aim at learning more about the interactions between these components and the impact that human activity is having on natural Earth processes. The Sentinel missions provide accurate, timely, long term and uninterrupted data to provide key information services, improving the way the environment is managed, and helping to mitigate the effects of climate change. The operational Sentinel satellites can also be exploited for scientific studies of the anthropocene. In the anthropocene human activities affect the whole planet and space is a very efficient means to measure their impact, but for relevant endeavours to be successful they can only be carried out in international cooperation. ESA maintains long-standing partnerships with other space agencies and institutions worldwide. In running its Earth observation programmes, ESA responds to societal needs and challenges and to requirements resulting from political priorities set by decision makers. Activities related to Climate Change are a prime example. Within ESA's Climate Change Initiative, 13 Essential Climate Variables are constantly monitored to create a long-term record of key geophysical parameters.

Exoplanet dynamics. Asynchronous rotation of Earth-mass planets in the habitable zone of lower-mass stars.

PubMed

Leconte, Jérémy; Wu, Hanbo; Menou, Kristen; Murray, Norman

2015-02-06

Planets in the habitable zone of lower-mass stars are often assumed to be in a state of tidally synchronized rotation, which would considerably affect their putative habitability. Although thermal tides cause Venus to rotate retrogradely, simple scaling arguments tend to attribute this peculiarity to the massive Venusian atmosphere. Using a global climate model, we show that even a relatively thin atmosphere can drive terrestrial planets' rotation away from synchronicity. We derive a more realistic atmospheric tide model that predicts four asynchronous equilibrium spin states, two being stable, when the amplitude of the thermal tide exceeds a threshold that is met for habitable Earth-like planets with a 1-bar atmosphere around stars more massive than ~0.5 to 0.7 solar mass. Thus, many recently discovered terrestrial planets could exhibit asynchronous spin-orbit rotation, even with a thin atmosphere. Copyright © 2015, American Association for the Advancement of Science.

Development of the AuScope Australian Earth Observing System

NASA Astrophysics Data System (ADS)

Rawling, T.

2017-12-01

Advances in monitoring technology and significant investment in new national research initiatives, will provide significant new opportunities for delivery of novel geoscience data streams from across the Australian continent over the next decade. The AuScope Australian Earth Observing System (AEOS) is linking field and laboratory infrastructure across Australia to form a national sensor array focusing on the Solid Earth. As such AuScope is working with these programs to deploy observational infrastructure, including MT, passive seismic, and GNSS networks across the entire Australian Continent. Where possible the observational grid will be co-located with strategic basement drilling in areas of shallow cover and tied with national reflection seismic and sampling transects. This integrated suite of distributed earth observation and imaging sensors will provide unprecedented imaging fidelity of our crust, across all length and time scales, to fundamental and applied researchers in the earth, environmental and geospatial sciences. The AEOS will the Earth Science community's Square Kilometer Array (SKA) - a distributed telescope that looks INTO the earth rather than away from it - a 10 million SKA. The AEOS is strongly aligned with other community strategic initiatives including the UNCOVER research program as well as other National Collaborative Research Infrastructure programs such as the Terrestrial Environmental Research Network (TERN) and the Integrated Marine Observing System (IMOS) providing an interdisciplinary collaboration platform across the earth and environmental sciences. There is also very close alignment between AuScope and similar international programs such as EPOS, the USArray and EarthCube - potential collaborative linkages we are currently in the process of pursuing more fomally. The AuScope AEOS Infrastructure System is ultimately designed to enable the progressive construction, refinement and ongoing enrichment of a live, "FAIR" four

Development of a Torsional Seismometer for measuring the rotational oscillations of the Earth.

NASA Astrophysics Data System (ADS)

Madziwa-Nussino, T. G.; Cowsik, R.; Wagoner, K.

2008-12-01

The motivations for the development and characterization of instruments capable of recording the rotations associated with seismic activity and normal mode oscillations were detailed extensively at the 2006 Fall- meeting of the American Geophysical Union in 2006 and in a special workshop at USGS-Menlo Park in 2007. This paper describes the effort and progress we have made in building a new instrument to be used for such measurements. Our prototype has two basic subsystems; a torsional oscillator and an optical lever for angular measurements. The essential idea behind the design maybe briefly stated as follows: A mechanical torsional oscillator with a natural frequency significantly below the lowest normal mode frequencies will couple negligibly to the rotational motions of the earth, even though the housing of the oscillator is firmly fixed to the earth. A sensitive optical lever, fixed to the Earth, observing such a balance can therefore faithfully measure the rotational oscillations of the Earth. The challenges we face in this development are two-fold: (a) the development of a mechanical torsional oscillator with a low enough natural frequency ~10- 3Hz and the fabrication of an optical lever with an angular resolution better than ~10- 6rad·Hz-1/2; (b) to make the instrument robust and field-worthy for the study of near-field strong motions at frequencies higher than ~10-2Hz. The initial implemented design is as follows: the balance bob consists of a circular mirror of diameter ~ 40mm, with its normal in the horizontal plane. The mirror is mounted within an aluminum framework whose moment of inertia may be adjusted as required and also used for capacitive damping of unwanted torsional oscillations. The configuration has a mass of under 50g and a moment of inertia of ~150g·cm2 about the suspension axis. The suspension fiber is made of SS-304 alloy with a cross section of 7μm × 110μm and length ~5cm. The angular frequency of natural oscillations for this

NASA's future Earth observation plans

NASA Astrophysics Data System (ADS)

Neeck, Steven P.; Paules, Granville E.; McCuistion Ramesh, J. D.

2004-11-01

NASA's Science Mission Directorate, working with its domestic and international partners, provides accurate, objective scientific data and analysis to advance our understanding of Earth system processes. Learning more about these processes will enable improved prediction capability for climate, weather, and natural hazards. Earth interactions occur on a continuum of spatial and temporal scales ranging from short-term weather to long-term climate, and from local and regional to global. Quantitatively describing these changes means precisely measuring from space scores of biological and geophysical parameters globally. New missions that SMD will launch in the coming decade will complement the first series of the Earth Observing System. These next generation systematic measurement missions are being planned to extend or enhance the record of science-quality data necessary for understanding and predicting global change. These missions include the NPOESS Preparatory Project, Ocean Surface Topography Mission, Global Precipitation Measurement, Landsat Data Continuity Mission, and an aerosol polarimetry mission called Glory. New small explorer missions will make first of a kind Earth observations. The Orbiting Carbon Observatory will measure sources and sinks of carbon to help the Nation and the world formulate effective strategies to constrain the amount of this greenhouse gas in the atmosphere. Aquarius will measure ocean surface salinity which is key to ocean circulation in the North Atlantic that produces the current era's mild climate in northern Europe. HYDROS will measure soil moisture globally. Soil moisture is critical to agriculture and to managing fresh water resources. NASA continues to design, develop and launch the Nation's civilian operational environmental satellites, in both polar and geostationary orbits, by agreement with the National Oceanic and Atmospheric Administration (NOAA). NASA plans to develop an advanced atmospheric sounder, GIFTS, for

Galileo's Earth-Moon portrait

NASA Astrophysics Data System (ADS)

Simarski, Lynn Teo

Research reported at an AGU session on Galileo's Earth/Moon flyby refined the spacecraft's distinctive portrait of the Earth-Moon system. The Galileo team presented dramatic new views of the Earth and Moon taken last December. Andrew P. Ingersoll showed a color movie of the rotating Earth, made through spectral filters with which Galileo viewed the Earth almost continuously for 25 hours.Galileo also made finely tuned observations of vegetation and clouds, using three very closely spaced spectral wavelengths in the near-infrared, explained W. Reid Thompson. In the resulting images, Argentinian grassland and Brazilian rain forest are clearly distinguished, demonstrating the applicability of this technique for routine monitoring of deforestation, shifts in vegetation due to climate, and other phenomena. Thompson suggested that this capability could be used on the Earth Observing System. One of the spectral bands may also have potential for monitoring cloud condensation, as it appears to differentiate actively condensing, vapor-heavy clouds from higher and drier clouds.

NCAR Earth Observing Laboratory - An End-to-End Observational Science Enterprise

NASA Astrophysics Data System (ADS)

Rockwell, A.; Baeuerle, B.; Grubišić, V.; Hock, T. F.; Lee, W. C.; Ranson, J.; Stith, J. L.; Stossmeister, G.

2017-12-01

Researchers who want to understand and describe the Earth System require high-quality observations of the atmosphere, ocean, and biosphere. Making these observations not only requires capable research platforms and state-of-the-art instrumentation but also benefits from comprehensive in-field project management and data services. NCAR's Earth Observing Laboratory (EOL) is an end-to-end observational science enterprise that provides leadership in observational research to scientists from universities, U.S. government agencies, and NCAR. Deployment: EOL manages the majority of the NSF Lower Atmosphere Observing Facilities, which includes research aircraft, radars, lidars, profilers, and surface and sounding systems. This suite is designed to address a wide range of Earth system science - from microscale to climate process studies and from the planet's surface into the Upper Troposphere/Lower Stratosphere. EOL offers scientific, technical, operational, and logistics support to small and large field campaigns across the globe. Development: By working closely with the scientific community, EOL's engineering and scientific staff actively develop the next generation of observing facilities, staying abreast of emerging trends, technologies, and applications in order to improve our measurement capabilities. Through our Design and Fabrication Services, we also offer high-level engineering and technical expertise, mechanical design, and fabrication to the atmospheric research community. Data Services: EOL's platforms and instruments collect unique datasets that must be validated, archived, and made available to the research community. EOL's Data Management and Services deliver high-quality datasets and metadata in ways that are transparent, secure, and easily accessible. We are committed to the highest standard of data stewardship from collection to validation to archival. Discovery: EOL promotes curiosity about Earth science, and fosters advanced understanding of the

STS-43 Earth observation of a colorful sunrise

NASA Image and Video Library

1991-08-11

STS-43 Earth observation taken aboard Atlantis, Orbiter Vehicle (OV) 104, captures the Earth's limb at sunrise with unusual cloud patterns silhouetted by the sunlight and rising into the terminator lines.

Earth Observations taken by Expedition 44 crewmember

NASA Image and Video Library

2015-06-20

ISS044E002419 (06/20/2015) --- This Earth observation of Iran was taken by members of Expedition 44 on the International Space Station on June 20, 2015. Described as "Earth Art" it is the western shore of Lake Urmia near Gülmanxana, Iran (~36.6N, 45.3E).

The Accuracy of Radio Interferometric Measurements of Earth Rotation

NASA Technical Reports Server (NTRS)

Eubanks, T. M.; Steppe, J. A.; Spieth, M. A.

1985-01-01

The accuracy of very long base interferometry earth rotation (UT1) measurements is examined by intercomparing TEMPO and POLARIS data for 1982 and the first half of 1983. None of these data are simultaneous, and so a proper intercomparison requires accounting for the scatter introduced by the rapid, unpredictable, UT1 variations driven by exchanges of angular momentum with the atmosphere. A statistical model of these variations, based on meteorological estimates of the Atmospheric Angular Momentum is derived, and the optimal linear (Kalman) smoother for this model is constructed. The scatter between smoothed and independent raw data is consistent with the residual formal errors, which do not depend upon the actual scatter of the UT1 data. This represents the first time that an accurate prediction of the scatter between UT1 data sets were possible.

Rotational properties of the Maria asteroid family

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kim, M.-J.; Byun, Y.-I.; Choi, Y.-J.

2014-03-01

The Maria family is regarded as an old-type (∼3 ± 1 Gyr) asteroid family that has experienced substantial collisional and dynamical evolution in the main belt. It is located near the 3:1 Jupiter mean-motion resonance area that supplies near-Earth asteroids to the inner solar system. We carried out observations of Maria family asteroids during 134 nights from 2008 July to 2013 May and derived synodic rotational periods for 51 objects, including newly obtained periods of 34 asteroids. We found that there is a significant excess of fast and slow rotators in the observed rotation rate distribution. The one-sample Kolmogorov-Smirnov testmore » confirms that the spin rate distribution is not consistent with a Maxwellian at a 92% confidence level. From correlations among rotational periods, amplitudes of light curves, and sizes, we conclude that the rotational properties of Maria family asteroids have been changed considerably by non-gravitational forces such as the YORP effect. Using a light-curve inversion method, we successfully determined the pole orientations for 13 Maria members and found an excess of prograde versus retrograde spins with a ratio (N{sub p} /N{sub r} ) of 3. This implies that the retrograde rotators could have been ejected by the 3:1 resonance into the inner solar system since the formation of the Maria family. We estimate that approximately 37-75 Maria family asteroids larger than 1 km have entered near-Earth space every 100 Myr.« less

NASA's Earth Observing Data and Information System

NASA Technical Reports Server (NTRS)

Mitchell, Andrew E.; Behnke, Jeanne; Lowe, Dawn; Ramapriyan, H. K.

2009-01-01

NASA's Earth Observing System Data and Information System (EOSDIS) has been a central component of NASA Earth observation program for over 10 years. It is one of the largest civilian science information system in the US, performing ingest, archive and distribution of over 3 terabytes of data per day much of which is from NASA s flagship missions Terra, Aqua and Aura. The system supports a variety of science disciplines including polar processes, land cover change, radiation budget, and most especially global climate change. The EOSDIS data centers, collocated with centers of science discipline expertise, archive and distribute standard data products produced by science investigator-led processing systems. Key to the success of EOSDIS is the concept of core versus community requirements. EOSDIS supports a core set of services to meet specific NASA needs and relies on community-developed services to meet specific user needs. EOSDIS offers a metadata registry, ECHO (Earth Observing System Clearinghouse), through which the scientific community can easily discover and exchange NASA s Earth science data and services. Users can search, manage, and access the contents of ECHO s registries (data and services) through user-developed and community-tailored interfaces or clients. The ECHO framework has become the primary access point for cross-Data Center search-and-order of EOSDIS and other Earth Science data holdings archived at the EOSDIS data centers. ECHO s Warehouse Inventory Search Tool (WIST) is the primary web-based client for discovering and ordering cross-discipline data from the EOSDIS data centers. The architecture of the EOSDIS provides a platform for the publication, discovery, understanding and access to NASA s Earth Observation resources and allows for easy integration of new datasets. The EOSDIS also has developed several methods for incorporating socioeconomic data into its data collection. Over the years, we have developed several methods for determining

Tidal Locking Of The Earth

NASA Astrophysics Data System (ADS)

Koohafkan, Michael

2006-05-01

The Moon's orbit and spin period are nearly synchronized, or tidally locked. Could the Moon's orbit and the Earth's spin eventually synchronize as well? The Moon's gravitational pull on the Earth produces tides in our oceans, and tidal friction gradually lengthens our days. Less obvious gravitational interactions between the Earth and Moon may also have effects on Earth's spin. The Earth is slightly distorted into an egg-like shape, and the torque exerted by the Moon on our equatorial bulge slowly changes the tilt of our spin axis. How do effects such as these change as the Moon drifts away from Earth? I will examine gravitational interactions between Earth and Moon to learn how they contribute to the deceleration of the Earth's rotation. My goal is to determine the amount of time it would take for the Earth's rotational speed to decelerate until the period of a single rotation matches the period of the Moon's orbit around Earth -- when the Earth is ``tidally locked'' with the Moon. I aim to derive a general mathematical expression for the rotational deceleration of the Earth due to Moon's gravitational influences.

Earth Observation Satellites and Chinese Applications

NASA Astrophysics Data System (ADS)

Li, D.

In this talk existing and future Earth observation satellites are briefly described These satellites include meteorological satellites ocean satellites land resources satellites cartographic satellites and gravimetric satellites The Chinese government has paid and will pay more attention to and put more effort into enhancing Chinese earth observation satellite programs in the next fifteen years The utilization of these satellites will effectively help human beings to solve problems it faces in areas such as population natural resources and environment and natural hazards The author will emphasize the originality of the scientific and application aspects of the Chinese program in the field of Earth observations The main applications include early warning and prevention of forest fires flooding and drought disaster water and ocean ice disasters monitoring of landslides and urban subsidence investigation of land cover change and urban expansion as well as urban and rural planning The author introduces the most up-to-date technology used by Chinese scientists including fusion and integration of multi-sensor multi-platform optical and SAR data of remote sensing Most applications in China have obtained much support from related international organizations and universities around the world These applications in China are helpful for economic construction and the efficient improvement of living quality

Patterns in Crew-Initiated Photography of Earth from ISS - Is Earth Observation a Salutogenic Experience?

NASA Technical Reports Server (NTRS)

Robinson, Julie A.; Slack, Kelley; Olson, V.; Trenchard, M.; Willis, K.; Baskin, P.

2006-01-01

This viewgraph presentation asks the question "Is the observation of earth from the ISS a positive (salutogenic) experience for crew members?"All images are distributed to the public via the "Gateway to Astronaut Photography of Earth at http://eol.jsc.nasa.gov. The objectives of the study are (1) Mine the dataset of Earth Observation photography--What can it tell us about the importance of viewing the Earth as a positive experience for the crewmembers? (2) Quantify extent to which photography was self-initiated (not requested by scientists) (3) Identify patterns photography activities versus scientific requested photography.

Coseismic Excitation of the Earth's Polar Motion

NASA Technical Reports Server (NTRS)

Chao, B. F.; Gross, R. S.

2000-01-01

Apart from the "shaking" near the epicenter that is the earthquake, a seismic event creates a permanent field of dislocation in the entire Earth. This redistribution of mass changes (slightly) the Earth's inertia tensor; and the Earth's rotation will change in accordance with the conservation of angular momentum. Similar to this seismic excitation of Earth rotation variations, the same mass redistribution causes (slight) changes in the Earth's gravitational field expressible in terms of changes in the Stokes coefficients of its harmonic expansion. In this paper, we give a historical background of the subject and discuss the related physics; we then compute the geodynamic effects caused by earthquakes based on normal-mode summation scheme. The effects are computed using the centroid moment tensor (CMT) solutions for 15,814 major earthquakes from Jan., 1977, through Feb., 1999, as provided in the Harvard CMT catalog. The computational results further strengthens these findings and conclusions: (i) the strong tendency for earthquakes to make the Earth rounder and more compact (however slightly) continues; (ii) so does the trend in the seismic "nudging" of the rotation pole toward the general direction of approx. 140 E, roughly opposite to that of the observed polar drift, but two orders of magnitude smaller in drift speed.

Continuity of Earth Radiation Budget Observations

NASA Astrophysics Data System (ADS)

Loeb, N. G.; Su, W.; Wong, T.; Priestley, K.

2017-12-01

Earth's climate is determined by the exchange of radiant energy between the Sun, Earth and space. The absorbed solar radiation at the top-of-atmosphere (TOA) fuels the climate system, providing the energy required for atmospheric and oceanic motions. Earth's radiation budget (ERB) involves a balance between how much solar energy Earth absorbs and how much terrestrial thermal infrared radiation is emitted to space. Because of its critical role in climate, continuous monitoring of the ERB is necessary for improved understanding and prediction of climate variability and change. NASA's long history in observing the TOA ERB is acknowledged in the 2007 and 2013 reports of the IPCC (IPCC 2007, 2013), the 2007 NRC Decadal Survey (NRC 2007), and the GCOS implementation plan of the WMO (GCOS 2016). A key reason for NASA's success in this area is due to its support of the CERES Project and its predecessor, ERBE. During ERBE, the TOA ERB was observed using both scanner and nonscanner broadband instruments. The CERES project consists of six scanner instruments flying alongside high-resolution spectral imagers (MODIS, VIIRS) in morning and afternoon sun-synchronous orbits. In addition to extending the ERBE TOA radiation budget record, CERES also provides observations of Earth's surface radiation budget with unprecedented accuracy. Here we assess the likelihood of a measurement gap in the ERB record. We show that unless a follow-on ERB instrument to the last available CERES copy (FM6) is built and launched, there is a significant risk of a measurement gap in the ERB record by the mid-2020s. A gap is of concern not only because the ERB would not be monitored during the gap period but also because it would be exceedingly difficult to tie the records before and after the gap together with sufficient accuracy for climate analyses. While ERB instruments are highly stable temporally, they lack the absolute accuracy needed to bridge a gap. Consequently, there is a requirement that

New Observational Evidence of Active Asteroid P/2010 A2: Slow Rotation of the Largest Fragment

NASA Astrophysics Data System (ADS)

Kim, Yoonyoung; Ishiguro, Masateru; Lee, Myung Gyoon

2017-06-01

We report new observations of the active asteroid P/2010 A2 taken when it made its closest approach to Earth (1.06 au in 2017 January) after its first discovery in 2010. Despite a crucial role of the rotational period in clarifying its ejection mechanism, the rotational property of P/2010 A2 has not yet been studied due to the extreme faintness of this tiny object (∼120 m in diameter). Taking advantage of the best observing geometry since the discovery, we succeed in obtaining the rotational light curve of the largest fragment with Gemini/GMOS-N. We find that (1) the largest fragment has a double-peaked period of 11.36 ± 0.02 hr spinning much slower than its critical spin period; (2) the largest fragment is a highly elongated object (a/b ≥ 1.94) with an effective radius of {61.9}-9.2+16.8 m; (3) the size distribution of the ejecta follows a broken power law (the power indices of the cumulative size distributions of the dust and fragments are 2.5 ± 0.1 and 5.2 ± 0.1, respectively); (4) the mass ratio of the largest fragment to the total ejecta is around 0.8; and (5) the dust cloud morphology is in agreement with the anisotropic ejection model in Kim et al. These new characteristics of the ejecta obtained in this work are favorable to the impact shattering hypothesis.

The Breath of Planet Earth: Atmospheric Circulation. Assimilation of Surface Wind Observations

NASA Technical Reports Server (NTRS)

Atlas, Robert; Bloom, Stephen; Otterman, Joseph

2000-01-01

Differences in air pressure are a major cause of atmospheric circulation. Because heat excites the movement of atoms, warm temperatures cause, air molecules to expand. Because those molecules now occupy a larger space, the pressure that their weight exerts is decreased. Air from surrounding high-pressure areas is pushed toward the low-pressure areas, creating circulation. This process causes a major pattern of global atmosphere movement known as meridional circulation. In this form of convection, or vertical air movement, heated equatorial air rises and travels through the upper atmosphere toward higher latitudes. Air just above the equator heads toward the North Pole, and air just below the equator moves southward. This air movement fills the gap created where increased air pressure pushes down cold air. The ,cold air moves along the surface back toward the equator, replacing the air masses that rise there. Another influence on atmospheric. circulation is the Coriolis force. Because of the Earth's rotation, large-scale wind currents move in the direction of this axial spin around low-pressure areas. Wind rotates counterclockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere. just as the Earth's rotation affects airflow, so too does its surface. In the phenomenon of orographic lifting, elevated topographic features such as mountain ranges lift air as it moves up their surface.

ESA Earth Observation missions at the service of geoscience

NASA Astrophysics Data System (ADS)

Aschbacher, Josef

2017-04-01

The intervention will present ESA's Earth Observation programmes and their relevance to geoscience. ESA's Earth observation missions are mainly grouped into three categories: The Sentinel satellites in the context of the European Copernicus Programme, the scientific Earth Explorers and the meteorological missions. Developments, applications and scientific results for the different mission types will be addressed, along with overall trends and boundary conditions. The Earth Explorers, who form the science and research element of ESA's Living Planet Programme, focus on the atmosphere, biosphere, hydrosphere, cryosphere and Earth's interior. The Earth Explorers also aim at learning more about the interactions between these components and the impact that human activity is having on natural Earth processes. The Sentinel missions provide accurate, timely, long term and uninterrupted data to provide key information services, improving the way the environment is managed, and helping to mitigate the effects of climate change. The operational Sentinel satellites can also be exploited for scientific endeavours. Meteorological satellites help to predict the weather and feature the most mature application of Earth observation. Over the last four decades satellites have been radically improving the accuracy of weather forecasts by providing unique and indispensable input data to numerical computation models. In addition, Essential Climate Variables (ECV) are constantly monitored within ESA's Climate Change Initiative in order to create a long-term record of key geophysical parameters. All of these activities can only be carried out in international cooperation. Accordingly, ESA maintains long-standing partnerships with other space agencies and relevant institutions worldwide. In running its Earth observation programmes, ESA responds to societal needs and challenges as well as to requirements resulting from political priorities, such as the United Nations' Sustainable Development

High-Definition Television (HDTV) Images for Earth Observations and Earth Science Applications

NASA Technical Reports Server (NTRS)

Robinson, Julie A.; Holland, S. Douglas; Runco, Susan K.; Pitts, David E.; Whitehead, Victor S.; Andrefouet, Serge M.

2000-01-01

As part of Detailed Test Objective 700-17A, astronauts acquired Earth observation images from orbit using a high-definition television (HDTV) camcorder, Here we provide a summary of qualitative findings following completion of tests during missions STS (Space Transport System)-93 and STS-99. We compared HDTV imagery stills to images taken using payload bay video cameras, Hasselblad film camera, and electronic still camera. We also evaluated the potential for motion video observations of changes in sunlight and the use of multi-aspect viewing to image aerosols. Spatial resolution and color quality are far superior in HDTV images compared to National Television Systems Committee (NTSC) video images. Thus, HDTV provides the first viable option for video-based remote sensing observations of Earth from orbit. Although under ideal conditions, HDTV images have less spatial resolution than medium-format film cameras, such as the Hasselblad, under some conditions on orbit, the HDTV image acquired compared favorably with the Hasselblad. Of particular note was the quality of color reproduction in the HDTV images HDTV and electronic still camera (ESC) were not compared with matched fields of view, and so spatial resolution could not be compared for the two image types. However, the color reproduction of the HDTV stills was truer than colors in the ESC images. As HDTV becomes the operational video standard for Space Shuttle and Space Station, HDTV has great potential as a source of Earth-observation data. Planning for the conversion from NTSC to HDTV video standards should include planning for Earth data archiving and distribution.

Flexible Description and Adaptive Processing of Earth Observation Data through the BigEarth Platform

NASA Astrophysics Data System (ADS)

Gorgan, Dorian; Bacu, Victor; Stefanut, Teodor; Nandra, Cosmin; Mihon, Danut

2016-04-01

The Earth Observation data repositories extending periodically by several terabytes become a critical issue for organizations. The management of the storage capacity of such big datasets, accessing policy, data protection, searching, and complex processing require high costs that impose efficient solutions to balance the cost and value of data. Data can create value only when it is used, and the data protection has to be oriented toward allowing innovation that sometimes depends on creative people, which achieve unexpected valuable results through a flexible and adaptive manner. The users need to describe and experiment themselves different complex algorithms through analytics in order to valorize data. The analytics uses descriptive and predictive models to gain valuable knowledge and information from data analysis. Possible solutions for advanced processing of big Earth Observation data are given by the HPC platforms such as cloud. With platforms becoming more complex and heterogeneous, the developing of applications is even harder and the efficient mapping of these applications to a suitable and optimum platform, working on huge distributed data repositories, is challenging and complex as well, even by using specialized software services. From the user point of view, an optimum environment gives acceptable execution times, offers a high level of usability by hiding the complexity of computing infrastructure, and supports an open accessibility and control to application entities and functionality. The BigEarth platform [1] supports the entire flow of flexible description of processing by basic operators and adaptive execution over cloud infrastructure [2]. The basic modules of the pipeline such as the KEOPS [3] set of basic operators, the WorDeL language [4], the Planner for sequential and parallel processing, and the Executor through virtual machines, are detailed as the main components of the BigEarth platform [5]. The presentation exemplifies the development

NASA's Earth Observing System (EOS): Observing the Atmosphere, Land, Oceans, and Ice from Space

NASA Technical Reports Server (NTRS)

King, Michael D.

2004-01-01

The Earth Observing System (EOS) is a space-based observing system comprised of a series of satellite sensors by which scientists can monitor the Earth, a Data and Information System (EOSDIS) enabling researchers worldwide to access the satellite data, and an interdisciplinary science research program to interpret the satellite data. During this year, the last of the first series of EOS missions, Aura, was launched. Aura is designed exclusively to conduct research on the composition, chemistry, and dynamics of the Earth's upper and lower atmosphere, employing multiple instruments on a single spacecraft. Aura is the third in a series of major Earth observing satellites to study the environment and climate change and is part of NASA's Earth Science Enterprise. The first and second missions, Terra and Aqua, are designed to study the land, oceans, atmospheric constituents (aerosols, clouds, temperature, and water vapor), and the Earth's radiation budget. The other seven EOS spacecraft include satellites to study (i) land cover & land use change, (ii) solar irradiance and solar spectral variation, (iii) ice volume, (iv) ocean processes (vector wind and sea surface topography), and (v) vertical variations of clouds, water vapor, and aerosols up to and including the stratosphere. Aura's chemistry measurements will also follow up on measurements that began with NASA's Upper Atmosphere Research Satellite and continue the record of satellite ozone data collected from the TOMS missions. In this presentation I will describe how scientists are using EOS data to examine the health of the earth's atmosphere, including atmospheric chemistry, aerosol properties, and cloud properties, with a special but not exclusive look at the latest earth observing mission, Aura.

NASA's Earth Observing System (EOS): Observing the Atmosphere, Land, Oceans, and Ice from Space

NASA Technical Reports Server (NTRS)

King, Michael D.

2005-01-01

The Earth Observing System (EOS) is a space-based observing system comprised of a series of satellite sensors by whch scientists can monitor the Earth, a Data and Information System (EOSDIS) enabling researchers worldwide to access the satellite data, and an interdisciplinary science research program to interpret the satellite data. During this year, the last of the first series of EOS missions, Aura, was launched. Aura is designed exclusively to conduct research on the composition, chemistry, and dynamics of the Earth's upper and lower atmosphere, employing multiple instruments on a single spacecraft. Aura is the third in a series of major Earth observing satellites to study the environment and climate change and is part of NASA's Earth Science Enterprise. The first and second missions, Terra and Aqua, are designed to study the land, oceans, atmospheric constituents (aerosols, clouds, temperature, and water vapor), and the Earth's radiation budget. The other seven EOS spacecraft include satellites to study (i) land cover & land use change, (ii) solar irradiance and solar spectral variation, (iii) ice volume, (iv) ocean processes (vector wind and sea surface topography), and (v) vertical variations of clouds, water vapor, and aerosols up to and including the stratosphere. Aura's chemistry measurements will also follow up on measurements that began with NASA's Upper Atmosphere Research Satellite and continue the record of satellite ozone data collected from the TOMS missions. In this presentation I will describe how scientists are using EOS data to examine the health of the earth's atmosphere, including atmospheric chemistry, aerosol properties, and cloud properties, with a special look at the latest earth observing mission, Aura.

Observation duration analysis for Earth surface features from a Moon-based platform

NASA Astrophysics Data System (ADS)

Ye, Hanlin; Guo, Huadong; Liu, Guang; Ren, Yuanzhen

2018-07-01

Earth System Science is a discipline that performs holistic and comprehensive research on various components of the Earth. One of a key issue for the Earth monitoring and observation is to enhance the observation duration, the time intervals during which the Earth surface features can be observed by sensors. In this work, we propose to utilise the Moon as an Earth observation platform. Thanks to the long distance between the Earth and the Moon, and the vast space on the lunar surface which is suitable for sensor installation, this Earth observation platform could have large spatial coverage, long temporal duration, and could perform multi-layer detection of the Earth. The line of sight between a proposed Moon-based platform and the Earth will change with different lunar surface positions; therefore, in this work, the position of the lunar surface was divided into four regions, including one full observation region and three incomplete observation regions. As existing methods are not able to perform global-scale observations, a Boolean matrix method was established to calculate the necessary observation durations from a Moon-based platform. Based on Jet Propulsion Laboratory (JPL) ephemerides and Earth Orientation Parameters (EOP), a formula was developed to describe the geometrical relationship between the Moon-based platform and Earth surface features in the unified spatial coordinate system and the unified time system. In addition, we compared the observation geometries at different positions on the lunar surface and two parameters that are vital to observation duration calculations were considered. Finally, an analysis method was developed. We found that the observation duration of a given Earth surface feature shows little difference regardless of sensor position within the full observation region. However, the observation duration for sensors in the incomplete observation regions is reduced by at least half. In summary, our results demonstrate the suitability

Earth Observations from Space: The First 50 Years of Scientific Achievements

NASA Technical Reports Server (NTRS)

2008-01-01

Observing Earth from space over the past 50 years has fundamentally transformed the way people view our home planet. The image of the "blue marble" is taken for granted now, but it was revolutionary when taken in 1972 by the crew on Apollo 17. Since then the capability to look at Earth from space has grown increasingly sophisticated and has evolved from simple photographs to quantitative measurements of Earth properties such as temperature, concentrations of atmospheric trace gases, and the exact elevation of land and ocean. Imaging Earth from space has resulted in major scientific accomplishments; these observations have led to new discoveries, transformed the Earth sciences, opened new avenues of research, and provided important societal benefits by improving the predictability of Earth system processes. This report highlights the scientific achievements made possible by the first five decades of Earth satellite observations by space-faring nations. It follows on a recent report from the National Research Council (NRC) entitled Earth Science and Applications from Space: National Imperatives for the Next Decade and Beyond, also referred to as the "decadal survey." Recognizing the increasing need for space observations, the decadal survey identifies future directions and priorities for Earth observations from space. This companion report was requested by the National Aeronautics and Space Administration (NASA) to highlight, through selected examples, important past contributions of Earth observations from space to our current understanding of the planet.

Can earthquake source inversion benefit from rotational ground motion observations?

NASA Astrophysics Data System (ADS)

Igel, H.; Donner, S.; Reinwald, M.; Bernauer, M.; Wassermann, J. M.; Fichtner, A.

2015-12-01

With the prospects of instruments to observe rotational ground motions in a wide frequency and amplitude range in the near future we engage in the question how this type of ground motion observation can be used to solve seismic inverse problems. Here, we focus on the question, whether point or finite source inversions can benefit from additional observations of rotational motions. In an attempt to be fair we compare observations from a surface seismic network with N 3-component translational sensors (classic seismometers) with those obtained with N/2 6-component sensors (with additional colocated 3-component rotational motions). Thus we keep the overall number of traces constant. Synthetic seismograms are calculated for known point- or finite-source properties. The corresponding inverse problem is posed in a probabilistic way using the Shannon information content as a measure how the observations constrain the seismic source properties. The results show that with the 6-C subnetworks the source properties are not only equally well recovered (even that would be benefitial because of the substantially reduced logistics installing N/2 sensors) but statistically significant some source properties are almost always better resolved. We assume that this can be attributed to the fact the (in particular vertical) gradient information is contained in the additional rotational motion components. We compare these effects for strike-slip and normal-faulting type sources. Thus the answer to the question raised is a definite "yes". The challenge now is to demonstrate these effects on real data.

The Crew Earth Observations Experiment: Earth System Science from the ISS

NASA Technical Reports Server (NTRS)

Stefanov, William L.; Evans, Cynthia A.; Robinson, Julie A.; Wilkinson, M. Justin

2007-01-01

This viewgraph presentation reviews the use of Astronaut Photography (AP) as taken from the International Space Station (ISS) in Earth System Science (ESS). Included are slides showing basic remote sensing theory, data characteristics of astronaut photography, astronaut training and operations, crew Earth observations group, targeting sites and acquisition, cataloging and database, analysis and applications for ESS, image analysis of particular interest urban areas, megafans, deltas, coral reefs. There are examples of the photographs and the analysis.

Earth observation mission operation of COMS during in-orbit test

NASA Astrophysics Data System (ADS)

Cho, Young-Min

2011-11-01

Communication Ocean Meteorological Satellite (COMS) for the hybrid mission of meteorological observation, ocean monitoring, and telecommunication service was launched onto Geostationary Earth Orbit on June 27, 2010 and it is currently under normal operation service after the In-Orbit Test (IOT) phase. The COMS is located on 128.2° East of the geostationary orbit. In order to perform the three missions, the COMS has 3 separate payloads, the meteorological imager (MI), the Geostationary Ocean Color Imager (GOCI), and the Ka-band antenna. Each payload is dedicated to one of the three missions, respectively. The MI and GOCI perform the Earth observation mission of meteorological observation and ocean monitoring, respectively. During the IOT phase the functionality and the performance of many aspects of the COMS satellite and ground station have been checked through the Earth observation mission operation for the observation of the meteorological phenomenon over several areas of the Earth and the monitoring of marine environments around the Korean peninsula. The Earth observation mission operation of COMS during the IOT phase is introduced in terms of mission operation characteristics, mission planning, and mission operation results for the missions of meteorological observation and ocean monitoring, respectively.

Prediction of secular acceleration of axial rotation of Mars

NASA Astrophysics Data System (ADS)

Barkin, Yu. V.

2009-04-01

Secular motion of the Earth pole and non-tidal acceleration of its diurnal rotation have obtained rather precise explanation with the help of simple one-point model of the directed transport of fluid masses from a southern hemisphere in northern hemisphere with the general direction, given by geocentric axis OP directed to pole P with coordinates 700N, 10403 E[1]. The another generalized model represents a system of two material points with masses m2 and m1, located on surface of the Earth at poles of geocentric axis OP. Masses are linearly changed in the time with velocities [2]: ṁ2 = 0.179 × 1015kg/yrand ṁ1 = 0.043 × 1015kg/yr. A reduction of fluid masses of the appropriate thin spherical layer of the Earth correspond to secular increasing of masses of model points. The specified model has allowed to explain values of fundamental geodynamic parameters observably and determined during decades: a direction and velocity of drift of a pole of the Earth; value of non-tidal acceleration of axial rotation; to explain a secular variations of coefficients of the second, third, fourth, sixth and eighth zonal harmonics of a geopotential; coefficients of secular changes of a surface of ocean for the last approximately 150 years; a direction of secular drift of a geocenter and other planetary phenomena [3]. The role of the angular momentum of redistributed masses of the Earth in rotation of the Earth appeared not essential at the given stage of researches. On the essence the offered model has semi-empirical character as it bases on values of velocities of change of masses of points and the given position of axis OP. For their determination and estimations the part of the observant data was used, and other parameters were designed under analytical formulas. The obtained results have precisely confirmed competency and affectivity of geodynamic model [4] about existence of secular drift of a liquid core along radial direction OP with velocity about 2.6 cm/yr in the

Determination of Earth rotation by the combination of data from different space geodetic systems

NASA Technical Reports Server (NTRS)

Archinal, Brent Allen

1987-01-01

Formerly, Earth Rotation Parameters (ERP), i.e., polar motion and UTI-UTC values, have been determined using data from only one observational system at a time, or by the combination of parameters previously obtained in such determinations. The question arises as to whether a simultaneous solution using data from several sources would provide an improved determination of such parameters. To pursue this reasoning, fifteen days of observations have been simulated using realistic networks of Lunar Laser Ranging (LLR), Satellite Laser Ranging (SLR) to Lageos, and Very Long Baseline Interferometry (VLBI) stations. A comparison has been done of the accuracy and precision of the ERP obtained from: (1) the individual system solutions, (2) the weighted means of those values, (3) all of the data by means of the combination of the normal equations obtained in 1, and (4) a grand solution with all the data. These simulations show that solutions done by the normal equation combination and grand solution methods provide the best or nearly the best ERP for all the periods considered, but that weighted mean solutions provide nearly the same accuracy and precision. VLBI solutions also provide similar accuracies.

Reference earth orbital research and applications investigations (blue book). Volume 4: Earth observations

NASA Technical Reports Server (NTRS)

1971-01-01

The earth observations capability of the space station and space shuttle program definition is discussed. The stress in the functional program element has been to update the sensor specifications and to shift some of the emphasis from sensors to experiments to be done aboard the facility. The earth observations facility will include provisions for data acquisition, sensor control and display, data analysis, and maintenance and repair. The facility is research and development in nature with a potential for operational applications.

Observations of Planet Crossing Asteroids

NASA Technical Reports Server (NTRS)

Tholen, David J.; Whiteley, Robert J.; Lambert, Joy; Connelley, Michael; Salyk, Colette

2002-01-01

The goals of this research were the physical and dynamical characterization of planet crossing asteroids (Earth crossers, Mars crossers, Centaurs, and Pluto crossers, meaning trans-Neptunian objects), including colorimetry, rotational studies, and astrometry. Highlights are listed as follows: 1) Produced one doctoral dissertation (R. J. Whiteley, A Compositional and Dynamical Survey of the Near-Earth Asteroids). A key result is the fraction of Q-type asteroids among the near-Earth population was found to be about one-third; 2) Had prediscovery image showing the binary nature of trans-Neptunian object 1998 WW31, which is the first TNO to have a satellite found in orbit around it; 3) Discovery of shortest known rotation period for any asteroid (2000 D08, rotation period 78 seconds); it is just one of several fast-rotating small asteroids observed during the course of this project; 4) Discovery of a Centaur asteroid (1998 QM107) with, at the time, the smallest known orbital eccentricity among the Centaurs (0.13) and nearly in a 1:1 resonance with Uranus (semimajor axis of 19.9 AU); 5) Discovery of Apollo-type asteroid 1999 OW3, with a surprisingly bright absolute magnitude of 14.6 (estimated diameter of 4.6 km), brightest Apollo found in that calendar year; 6) Discovery of Aten-type asteroid 2000 SG344, which has the highest cumulative Earth impact probability among the near-Earth asteroids and a very Earth-similar orbit; 7) Instrumental in repairing the orbit of a numbered near-Earth asteroid for which prediscovery observations had been mis-attributed to it (2000 VN2); 8) Second-opposition recovery of 30-meter diameter Apollo-type asteroid 1998 KY26 in early 2002 when it was at a favorable magnitude of 24.8; 9) Primary contributor of astrometric observations of the CONTOUR fragments to the CONTOUR project following the failure of the spacecraft s kick motor; and 10) Development of orbit and ephemeris computation code that handles short observational arcs

Observation and integrated Earth-system science: A roadmap for 2016-2025

NASA Astrophysics Data System (ADS)

Simmons, Adrian; Fellous, Jean-Louis; Ramaswamy, Venkatachalam; Trenberth, Kevin; Asrar, Ghassem; Balmaseda, Magdalena; Burrows, John P.; Ciais, Philippe; Drinkwater, Mark; Friedlingstein, Pierre; Gobron, Nadine; Guilyardi, Eric; Halpern, David; Heimann, Martin; Johannessen, Johnny; Levelt, Pieternel F.; Lopez-Baeza, Ernesto; Penner, Joyce; Scholes, Robert; Shepherd, Ted

2016-05-01

This report is the response to a request by the Committee on Space Research of the International Council for Science to prepare a roadmap on observation and integrated Earth-system science for the coming ten years. Its focus is on the combined use of observations and modelling to address the functioning, predictability and projected evolution of interacting components of the Earth system on timescales out to a century or so. It discusses how observations support integrated Earth-system science and its applications, and identifies planned enhancements to the contributing observing systems and other requirements for observations and their processing. All types of observation are considered, but emphasis is placed on those made from space. The origins and development of the integrated view of the Earth system are outlined, noting the interactions between the main components that lead to requirements for integrated science and modelling, and for the observations that guide and support them. What constitutes an Earth-system model is discussed. Summaries are given of key cycles within the Earth system. The nature of Earth observation and the arrangements for international coordination essential for effective operation of global observing systems are introduced. Instances are given of present types of observation, what is already on the roadmap for 2016-2025 and some of the issues to be faced. Observations that are organised on a systematic basis and observations that are made for process understanding and model development, or other research or demonstration purposes, are covered. Specific accounts are given for many of the variables of the Earth system. The current status and prospects for Earth-system modelling are summarized. The evolution towards applying Earth-system models for environmental monitoring and prediction as well as for climate simulation and projection is outlined. General aspects of the improvement of models, whether through refining the

Competing Structural Instabilities in the Ruddlesden–Popper Derivatives HRTiO 4 (R = Rare Earths): Oxygen Octahedral Rotations Inducing Noncentrosymmetricity and Layer Sliding Retaining Centrosymmetricity

DOE PAGES

Sen Gupta, Arnab; Akamatsu, Hirofumi; Brown, Forrest G.; ...

2016-12-06

We report the discovery of noncentrosymmetry in the family of HRTiO 4 (R = Eu, Gd, Dy) layered oxides possessing a Ruddlesden-Popper derivative structure, by second harmonic generation and synchrotron x-ray diffraction with the support of density functional theory calculations. These oxides were previously thought to possess inversion symmetry. Here, inversion symmetry is broken by oxygen octahedral rotations, a mechanism that is not active in simple perovskites. We discover a competition between oxygen octahedral rotations and sliding of the octahedral perovskite blocks at the OH layers. For the smaller rare earth ions, R = Eu, Gd, Dy, which favor themore » octahedral rotations, noncentrosymmetry is present but the sliding at the OH layer is absent. For the larger rare earth ions, R = Nd and Sm, the octahe-dral rotations are absent, but sliding of the octahedral blocks at the OH layer is present, likely to optimize the hydrogen bond length arising from the directional nature of these bonds in the crystal structure. The study reveals a new mechanism for inducing noncentrosymmetry in layered oxides, and chemical-structural effects related to rare earth ion size and hydrogen bonding that can turn this mechanism on and off. In conclusion, we construct a complete phase diagram of temperature versus rare earth ionic radius for the HRTiO 4 family.« less

Competing Structural Instabilities in the Ruddlesden–Popper Derivatives HRTiO 4 (R = Rare Earths): Oxygen Octahedral Rotations Inducing Noncentrosymmetricity and Layer Sliding Retaining Centrosymmetricity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Sen Gupta, Arnab; Akamatsu, Hirofumi; Brown, Forrest G.

We report the discovery of noncentrosymmetry in the family of HRTiO 4 (R = Eu, Gd, Dy) layered oxides possessing a Ruddlesden-Popper derivative structure, by second harmonic generation and synchrotron x-ray diffraction with the support of density functional theory calculations. These oxides were previously thought to possess inversion symmetry. Here, inversion symmetry is broken by oxygen octahedral rotations, a mechanism that is not active in simple perovskites. We discover a competition between oxygen octahedral rotations and sliding of the octahedral perovskite blocks at the OH layers. For the smaller rare earth ions, R = Eu, Gd, Dy, which favor themore » octahedral rotations, noncentrosymmetry is present but the sliding at the OH layer is absent. For the larger rare earth ions, R = Nd and Sm, the octahe-dral rotations are absent, but sliding of the octahedral blocks at the OH layer is present, likely to optimize the hydrogen bond length arising from the directional nature of these bonds in the crystal structure. The study reveals a new mechanism for inducing noncentrosymmetry in layered oxides, and chemical-structural effects related to rare earth ion size and hydrogen bonding that can turn this mechanism on and off. In conclusion, we construct a complete phase diagram of temperature versus rare earth ionic radius for the HRTiO 4 family.« less

Probable Rotation States of Rocket Bodies in Low Earth Orbit

NASA Astrophysics Data System (ADS)

Ojakangas, G.; Anz-Meador, P.; Cowardin, H.

2012-09-01

cannot cause precession periods shorter than a week, or more likely, months. Thus forced precession is probably not observable over observation campaigns spanning a few days or less. Spin-orbit resonances are likely for low rotation rates approaching the mean motion, possibly causing large deviations between the symmetry axis and the geocentric direction. An expression for the eddy current torque on an arbitrarily rotating cylinder, hitherto not available in the literature, is presented here. Numerical integrations of the equations of motion for a cylindrical RB in LEO with arbitrary initial conditions and subject to eddy current and gravity gradient torques as well as prescribed internal dissipation are in progress. Acknowledgements: This work was produced under NASA contract NNJ05HI05.

Policy Document on Earth Observation for Urban Planning and Management: State of the Art and Recommendations for Application of Earth Observation in Urban Planning

NASA Technical Reports Server (NTRS)

Nichol, Janet; King, Bruce; Xiaoli, Ding; Dowman, Ian; Quattrochi, Dale; Ehlers, Manfred

2007-01-01

A policy document on earth observation for urban planning and management resulting from a workshop held in Hong Kong in November 2006 is presented. The aim of the workshop was to provide a forum for researchers and scientists specializing in earth observation to interact with practitioners working in different aspects of city planning, in a complex and dynamic city, Hong Kong. A summary of the current state of the art, limitations, and recommendations for the use of earth observation in urban areas is presented here as a policy document.

Priorities to Advance Monitoring of Ecosystem Services Using Earth Observation.

PubMed

Cord, Anna F; Brauman, Kate A; Chaplin-Kramer, Rebecca; Huth, Andreas; Ziv, Guy; Seppelt, Ralf

2017-06-01

Managing ecosystem services in the context of global sustainability policies requires reliable monitoring mechanisms. While satellite Earth observation offers great promise to support this need, significant challenges remain in quantifying connections between ecosystem functions, ecosystem services, and human well-being benefits. Here, we provide a framework showing how Earth observation together with socioeconomic information and model-based analysis can support assessments of ecosystem service supply, demand, and benefit, and illustrate this for three services. We argue that the full potential of Earth observation is not yet realized in ecosystem service studies. To provide guidance for priority setting and to spur research in this area, we propose five priorities to advance the capabilities of Earth observation-based monitoring of ecosystem services. Copyright © 2017 Elsevier Ltd. All rights reserved.

Earth Observations

NASA Image and Video Library

2010-09-09

ISS024-E-014071 (9 Sept. 2010) --- This striking panoramic view of the southwestern USA and Pacific Ocean is an oblique image photographed by an Expedition 24 crew member looking outwards at an angle from the International Space Station (ISS). While most unmanned orbital satellites view Earth from a nadir perspective?in other words, collecting data with a ?straight down? viewing geometry?crew members onboard the space station can acquire imagery at a wide range of viewing angles using handheld digital cameras. The ISS nadir point (the point on Earth?s surface directly below the spacecraft) was located in northwestern Arizona, approximately 260 kilometers to the east-southeast, when this image was taken. The image includes parts of the States of Arizona, Nevada, Utah, and California together with a small segment of the Baja California, Mexico coastline at center left. Several landmarks and physiographic features are readily visible. The Las Vegas, NV metropolitan area appears as a gray region adjacent to the Spring Mountains and Sheep Range (both covered by white clouds). The Grand Canyon, located on the Colorado Plateau in Arizona, is visible (lower left) to the east of Las Vegas with the blue waters of Lake Mead in between. The image also includes the Mojave Desert, stretching north from the Salton Sea (left) to the Sierra Nevada mountain range. The Sierra Nevada range is roughly 640 kilometers long (north-south) and forms the boundary between the Central Valley of California and the adjacent Basin and Range. The Basin and Range is so called due to the pattern of long linear valleys separated by parallel linear mountain ranges ? this landscape, formed by extension and thinning of Earth?s crust, is particularly visible at right.

The role of GPS in precise earth observation

NASA Technical Reports Server (NTRS)

Yunck, Thomas P.; Lindal, Gunnar F.; Liu, Chao-Han

1988-01-01

The potential of the Global Positioning System (GPS) for precise earth observation is evaluated. It is projected that soon GPS will be utilized to track remote-sensing satellites with subdecimeter accuracy. The first will be Topex/Poseidon, a US/French ocean altimetry mission to be launched in 1991. In addition, it is suggested that developments planned for future platforms may push orbit accuracy near 1 cm within a decade. GPS receivers on some platforms will track the signals down to the earth limb to observe occultation by intervening media. This will provide comprehensive information on global temperature and climate and help detect the possible onset of a greenhouse effect. It is also projected that dual-frequency observations will be used to trace the flow of energy across earth systems through detection of ionospheric gravity waves, and to map the structure of the ionosphere by computer tomography.

Copernicus Earth observation programme

NASA Astrophysics Data System (ADS)

Žlebir, Silvo

European Earth observation program Copernicus is an EU-wide programme that integrates satellite data, in-situ data and modeling to provide user-focused information services to support policymakers, researchers, businesses and citizens. Land monitoring service and Emergency service are fully operational already, Atmosphere monitoring service and Marine environment monitoring service are preoperational and will become fully operational in the following year, while Climate change service and Security service are in an earlier development phase. New series of a number of dedicated satellite missions will be launched in the following years, operated by the European Space Agency and EUMETSAT, starting with Sentinel 1A satellite early this year. Ground based, air-borne and sea-borne in-situ data are provided by different international networks and organizations, EU member states networks etc. European Union is devoting a particular attention to secure a sustainable long-term operational provision of the services. Copernicus is also stated as a European Union’s most important contribution to Global Earth Observation System of Systems (GEOSS). The status and the recent development of the Copernicus programme will be presented, together with its future perspective. As Copernicus services have already demonstrated their usability and effectiveness, some interesting cases of their deployment will be presented. Copernicus free and open data policy, supported by a recently adopted EU legislative act, will also be presented.

Observing Coronal Mass Ejections from the Sun-Earth L5 Point

NASA Astrophysics Data System (ADS)

Gopalswamy, N.; Davila, J. M.; St Cyr, O. C.

2013-12-01

Coronal mass ejections (CMEs) are the most energetic phenomenon in the heliosphere and are known to be responsible for severe space weather. Most of the current knowledge on CMEs accumulated over the past few decades has been derived from observations made from the Sun-Earth line, which is not the ideal vantage point to observe Earth-affecting CMEs (Gopalswamy et al., 2011a,b). The STEREO mission viewed CMEs from points away from the Sun-Earth line and demonstrated the importance of such observations in understanding the three-dimensional structure of CMEs and their true kinematics. In this paper, we show that it is advantageous to observe CMEs from the Sun-Earth L5 point in studying CMEs that affect Earth. In particular, these observations are important in identifying that part of the CME that is likely to arrive at Earth. L5 observations are critical for several aspects of CME studies such as: (i) they can also provide near-Sun space speed of CMEs, which is an important input for modeling Earth-arriving CMEs, (ii) backside and frontside CMEs can be readily distinguished even without inner coronal imagers, and (iii) preceding CMEs in the path of Earth-affecting CMEs can be identified for a better estimate of the travel time, which may not be possible from the Sun-Earth line. We also discuss how the L5 vantage point compares with the Sun-Earth L4 point for observing Earth-affecting CMEs. References Gopalswamy, N., Davila, J. M., St. Cyr, O. C., Sittler, E. C., Auchère, F., Duvall, T. L., Hoeksema, J. T., Maksimovic, M., MacDowall, R. J., Szabo, A., Collier, M. R. (2011a), Earth-Affecting Solar Causes Observatory (EASCO): A potential International Living with a Star Mission from Sun-Earth L5 JASTP 73, 658-663, DOI: 10.1016/j.jastp.2011.01.013 Gopalswamy, N., Davila, J. M., Auchère, F., Schou, J., Korendyke, C. M. Shih, A., Johnston, J. C., MacDowall, R. J., Maksimovic, M., Sittler, E., et al. (2011b), Earth-Affecting Solar Causes Observatory (EASCO): a mission at

Origin of the Earth's Electromagnetic Field Based on the Pulsating Mantle Hypothesis (PMH)

NASA Astrophysics Data System (ADS)

Gholibeigian, Hassan

2017-11-01

In PMH, the Earth's Inner Core's Dislocation (ICD) and Outer Core's Bulge (OCB) phenomena are generated by unbalanced gravitational fields of the Sun and Moon on the Earth. Distance between the Earth's center and inner core's center varies permanently in magnitude and direction inside two hemispheres. Geometrical loci of the inner core's center has the shape of back and force spiral cone in each hemisphere. In other words, the inner core is rotating fast in the outer core inverse of the Earth's rotation a round per day. This mechanism speed up the processes inside the core and generates a Large Scale Forced Convection System (LSFCS) inverse of the Earth's rotation in the core. The LSFCS is the origin of the Earth's electromagnetic field. The LSFCS generates huge mass transfer and momentum of inertia inside the Earth too. The inner core's axis which is the Earth's electromagnetic axis doesn't cross the Earth's geophysical axis and rotates around it per day. The mechanism of this LSFCS has diurnal, monthly and yearly cycles. These cycles are sources of the Earth's electromagnetic field variability. Direction of the variable Earth's magnetic field lines from the South Pole (hemisphere) to the sky and 146 seconds/years apparent solar day length variations can be two observable factors for this mechanism. This dynamic system may occurred inside the other planets like the Sun and the Jupiter.

The Group on Earth Observations (GEO) through 2025

NASA Astrophysics Data System (ADS)

Ryan, Barbara; Cripe, Douglas

Ministers from the Group on Earth Observations (GEO) Member governments, meeting in Geneva, Switzerland in January 2014, unanimously renewed the mandate of GEO through 2025. Through a Ministerial Declaration, they reconfirmed that GEO’s guiding principles of collaboration in leveraging national, regional and global investments and in developing and coordinating strategies to achieve full and open access to Earth observations data and information in order to support timely and knowledge-based decision-making - are catalysts for improving the quality of life of people around the world, advancing global sustainability, and preserving the planet and its biodiversity. GEO Ministers acknowledged and valued the contributions of GEO Member governments and invited all remaining Member States of the United Nations to consider joining GEO. The Ministers also encouraged all Members to strengthen national GEO arrangements, and - of particular interest to COSPAR - they highlighted the unique contributions of Participating Organizations. In this regard, ten more organizations saw their applications approved by Plenary and joined the ranks along with COSPAR to become a Participating Organization in GEO, bringing the current total to 77. Building on the efforts of a Post-2015 Working Group, in which COSPAR participated, Ministers provided additional guidance for GEO and the evolution of its Global Earth Observation System of System (GEOSS) through 2025. Five key areas of activities for the next decade include the following: 1.) Advocating for the value of Earth observations and the need to continue improving Earth observation worldwide; 2.) Urging the adoption and implementation of data sharing principles globally; 3.) Advancing the development of the GEOSS information system for the benefit of users; 4.) Developing a comprehensive interdisciplinary knowledge base defining and documenting observations needed for all disciplines and facilitate availability and accessibility of

Correlations Between Variations in Solar EUV and Soft X-Ray Irradiance and Photoelectron Energy Spectra Observed on Mars and Earth

NASA Technical Reports Server (NTRS)

Peterson, W. K.; Brain, D. A.; Mitchell, D. L.; Bailey, S. M.; Chamberlin, P. C.

2013-01-01

Solar extreme ultraviolet (EUV; 10-120 nm) and soft X-ray (XUV; 0-10 nm) radiation are major heat sources for the Mars thermosphere as well as the primary source of ionization that creates the ionosphere. In investigations of Mars thermospheric chemistry and dynamics, solar irradiance models are used to account for variations in this radiation. Because of limited proxies, irradiance models do a poor job of tracking the significant variations in irradiance intensity in the EUV and XUV ranges over solar rotation time scales when the Mars-Sun-Earth angle is large. Recent results from Earth observations show that variations in photoelectron energy spectra are useful monitors of EUV and XUV irradiance variability. Here we investigate photoelectron energy spectra observed by the Mars Global Surveyor (MGS) Electron Reflectometer (ER) and the FAST satellite during the interval in 2005 when Earth, Mars, and the Sun were aligned. The Earth photoelectron data in selected bands correlate well with calculations based on 1 nm resolution observations above 27 nm supplemented by broadband observations and a solar model in the 0-27 nm range. At Mars, we find that instrumental and orbital limitations to the identifications of photoelectron energy spectra in MGS/ER data preclude their use as a monitor of solar EUV and XUV variability. However, observations with higher temporal and energy resolution obtained at lower altitudes on Mars might allow the separation of the solar wind and ionospheric components of electron energy spectra so that they could be used as reliable monitors of variations in solar EUV and XUV irradiance than the time shifted, Earth-based, F(10.7) index currently used.

Correlations between variations in solar EUV and soft X-ray irradiance and photoelectron energy spectra observed on Mars and Earth

NASA Astrophysics Data System (ADS)

Peterson, W. K.; Brain, D. A.; Mitchell, D. L.; Bailey, S. M.; Chamberlin, P. C.

2013-11-01

extreme ultraviolet (EUV; 10-120 nm) and soft X-ray (XUV; 0-10 nm) radiation are major heat sources for the Mars thermosphere as well as the primary source of ionization that creates the ionosphere. In investigations of Mars thermospheric chemistry and dynamics, solar irradiance models are used to account for variations in this radiation. Because of limited proxies, irradiance models do a poor job of tracking the significant variations in irradiance intensity in the EUV and XUV ranges over solar rotation time scales when the Mars-Sun-Earth angle is large. Recent results from Earth observations show that variations in photoelectron energy spectra are useful monitors of EUV and XUV irradiance variability. Here we investigate photoelectron energy spectra observed by the Mars Global Surveyor (MGS) Electron Reflectometer (ER) and the FAST satellite during the interval in 2005 when Earth, Mars, and the Sun were aligned. The Earth photoelectron data in selected bands correlate well with calculations based on 1 nm resolution observations above 27 nm supplemented by broadband observations and a solar model in the 0-27 nm range. At Mars, we find that instrumental and orbital limitations to the identifications of photoelectron energy spectra in MGS/ER data preclude their use as a monitor of solar EUV and XUV variability. However, observations with higher temporal and energy resolution obtained at lower altitudes on Mars might allow the separation of the solar wind and ionospheric components of electron energy spectra so that they could be used as reliable monitors of variations in solar EUV and XUV irradiance than the time shifted, Earth-based, F10.7 index currently used.

Earth Observation

NASA Image and Video Library

2014-07-19

ISS040-E-070424 (19 July 2014) --- One of the Expedition 40 crew members aboard the Earth-orbiting International Space Station recorded this July 19 image of wildfires which are plaguing the Northwest and causing widespread destruction. The orbital outpost was flying 223 nautical miles above Earth at the time of the photo. Lightning has been given as the cause of the Ochoco Complex fires in the Ochoco National Forest in central Oregon. The complex has gotten larger since this photo was taken.

Understanding USGS user needs and Earth observing data use for decision making

NASA Astrophysics Data System (ADS)

Wu, Z.

2016-12-01

US Geological Survey (USGS) initiated the Requirements, Capabilities and Analysis for Earth Observations (RCA-EO) project in the Land Remote Sensing (LRS) program, collaborating with the National Oceanic and Atmospheric Administration (NOAA) to jointly develop the supporting information infrastructure - The Earth Observation Requirements Evaluation Systems (EORES). RCA-EO enables us to collect information on current data products and projects across the USGS and evaluate the impacts of Earth observation data from all sources, including spaceborne, airborne, and ground-based platforms. EORES allows users to query, filter, and analyze usage and impacts of Earth observation data at different organizational level within the bureau. We engaged over 500 subject matter experts and evaluated more than 1000 different Earth observing data sources and products. RCA-EO provides a comprehensive way to evaluate impacts of Earth observing data on USGS mission areas and programs through the survey of 345 key USGS products and services. We paid special attention to user feedback about Earth observing data to inform decision making on improving user satisfaction. We believe the approach and philosophy of RCA-EO can be applied in much broader scope to derive comprehensive knowledge of Earth observing systems impacts and usage and inform data products development and remote sensing technology innovation.

Autonomous aerial observations to extend and complement the Earth Observing System: a science-driven systems-oriented approach

NASA Astrophysics Data System (ADS)

Sandford, Stephen P.; Harrison, F. W.; Langford, John; Johnson, James W.; Qualls, Garry; Emmitt, David; Jones, W. Linwood; Shugart, Herman H., Jr.

2004-12-01

The current Earth observing capability depends primarily on spacecraft missions and ground-based networks to provide the critical on-going observations necessary for improved understanding of the Earth system. Aircraft missions play an important role in process studies but are limited to relatively short-duration flights. Suborbital observations have contributed to global environmental knowledge by providing in-depth, high-resolution observations that space-based and in-situ systems are challenged to provide; however, the limitations of aerial platforms - e.g., limited observing envelope, restrictions associated with crew safety and high cost of operations have restricted the suborbital program to a supporting role. For over a decade, it has been recognized that autonomous aerial observations could potentially be important. Advances in several technologies now enable autonomous aerial observation systems (AAOS) that can provide fundamentally new observational capability for Earth science and applications and thus lead scientists and engineers to rethink how suborbital assets can best contribute to Earth system science. Properly developed and integrated, these technologies will enable new Earth science and operational mission scenarios with long term persistence, higher-spatial and higher-temporal resolution at lower cost than space or ground based approaches. This paper presents the results of a science driven, systems oriented study of broad Earth science measurement needs. These needs identify aerial mission scenarios that complement and extend the current Earth Observing System. These aerial missions are analogous to space missions in their complexity and potential for providing significant data sets for Earth scientists. Mission classes are identified and presented based on science driven measurement needs in atmospheric, ocean and land studies. Also presented is a nominal concept of operations for an AAOS: an innovative set of suborbital assets that

Rapid Ice-Sheet Changes and Mechanical Coupling to Solid-Earth/Sea-Level and Space Geodetic Observation

NASA Astrophysics Data System (ADS)

Adhikari, S.; Ivins, E. R.; Larour, E. Y.

2015-12-01

Perturbations in gravitational and rotational potentials caused by climate driven mass redistribution on the earth's surface, such as ice sheet melting and terrestrial water storage, affect the spatiotemporal variability in global and regional sea level. Here we present a numerically accurate, computationally efficient, high-resolution model for sea level. Unlike contemporary models that are based on spherical-harmonic formulation, the model can operate efficiently in a flexible embedded finite-element mesh system, thus capturing the physics operating at km-scale yet capable of simulating geophysical quantities that are inherently of global scale with minimal computational cost. One obvious application is to compute evolution of sea level fingerprints and associated geodetic and astronomical observables (e.g., geoid height, gravity anomaly, solid-earth deformation, polar motion, and geocentric motion) as a companion to a numerical 3-D thermo-mechanical ice sheet simulation, thus capturing global signatures of climate driven mass redistribution. We evaluate some important time-varying signatures of GRACE inferred ice sheet mass balance and continental hydrological budget; for example, we identify dominant sources of ongoing sea-level change at the selected tide gauge stations, and explain the relative contribution of different sources to the observed polar drift. We also report our progress on ice-sheet/solid-earth/sea-level model coupling efforts toward realistic simulation of Pine Island Glacier over the past several hundred years.

NASA's Earth Observations of the Global Environment

NASA Technical Reports Server (NTRS)

King, Michael D.

2005-01-01

A birds eye view of the Earth from afar and up close reveals the power and magnificence of the Earth and juxtaposes the simultaneous impacts and powerlessness of humankind. The NASA Electronic Theater presents Earth science observations and visualizations in an historical perspective. Fly in from outer space to Africa and Cape Town. See the latest spectacular images from NASA & NOAA remote sensing missions like Meteosat, TRMM, Landsat 7, and Terra, which will be visualized and explained in the context of global change. See visualizations of global data sets currently available from Earth orbiting satellites, including the Earth at night with its city lights, aerosols from biomass burning in the Middle East and Africa, and retreat of the glaciers on Mt. Kilimanjaro. See the dynamics of vegetation growth and decay over Africa over 17 years. New visualization tools allow us to roam & zoom through massive global mosaic images including Landsat and Terra tours of Africa and South America, showing land use and land cover change from Bolivian highlands. Spectacular new visualizations of the global atmosphere & oceans are shown. See massive dust storms sweeping across Africa and across the Atlantic to the Caribbean and Amazon basin. See ocean vortexes and currents that bring up the nutrients to feed tiny phytoplankton and draw the fish, pant whales and fisher- man. See how the ocean blooms in response to these currents and El Nino/La Nifia. We will illustrate these and other topics with a dynamic theater-style presentation, along with animations of satellite launch deployments and orbital mapping to highlight aspects of Earth observations from space.

Propagation Velocity of Solid Earth Tides

NASA Astrophysics Data System (ADS)

Pathak, S.

2017-12-01

One of the significant considerations in most of the geodetic investigations is to take into account the outcome of Solid Earth tides on the location and its consequent impact on the time series of coordinates. In this research work, the propagation velocity resulting from the Solid Earth tides between the Indian stations is computed. Mean daily coordinates for the stations have been computed by applying static precise point positioning technique for a day. The computed coordinates are used as an input for computing the tidal displacements at the stations by Gravity method along three directions at 1-minute interval for 24 hours. Further the baseline distances are computed between four Indian stations. Computation of the propagation velocity for Solid Earth tides can be done by the virtue of study of the concurrent effect of it in-between the stations of identified baseline distance along with the time consumed by the tides for reaching from one station to another. The propagation velocity helps in distinguishing the impact at any station if the consequence at a known station for a specific time-period is known. Thus, with the knowledge of propagation velocity, the spatial and temporal effects of solid earth tides can be estimated with respect to a known station. As theoretically explained, the tides generated are due to the position of celestial bodies rotating about Earth. So the need of study is to observe the correlation of propagation velocity with the rotation speed of the Earth. The propagation velocity of Solid Earth tides comes out to be in the range of 440-470 m/s. This velocity comes out to be in a good agreement with the Earth's rotation speed.

Observation of the Earth liquid core resonance by extensometers

NASA Astrophysics Data System (ADS)

Bán, Dóra; Mentes, Gyula

2016-04-01

The axis of the fluid outer core of the Earth and the rotation axis of the mantle do not coincide therefore restoring forces are set up at the core-mantle boundary which try to realign the two axes causing a resonance effect. In celestial reference system it is called the "Free Core Nutation" (FCN), which can be characterized by a period of 432 days while in the Earth reference system it is called the "Nearly Diurnal Free Wobble" (NDFW). The frequency of this phenomenon is near to the diurnal tidal frequencies, especially to P1 and K1 waves. Due to its resonance effect this phenomenon can be detected also by quartz tube extensometers suitable for Earth tides recording. In this study data series measured in several extensometric stations were used to reveal the presence of the FCN resonance. In the Pannonian Basin there are five observatories where extensometric measurements were carried out in different lengths of time. Four stations in Hungary: Sopronbánfalva Geodynamical Observatory (2000-2014), Budapest Mátyáshegy Gravity and Geodynamic Observatory (2005-2012), Pécs uranium mine (1991-1999), Bakonya, near to Pécs (2004-2005) and in Slovakia: Vyhne Earth Tide Observatory (2001-2013). Identical instrumentation in different observatories provides the opportunity to compare measurements with various topography, geology and environmental parameters. The results are also compared to values inferred from extensometric measurements in other stations.

Livingstone Model-Based Diagnosis of Earth Observing One Infusion Experiment

NASA Technical Reports Server (NTRS)

Hayden, Sandra C.; Sweet, Adam J.; Christa, Scott E.

2004-01-01

The Earth Observing One satellite, launched in November 2000, is an active earth science observation platform. This paper reports on the progress of an infusion experiment in which the Livingstone 2 Model-Based Diagnostic engine is deployed on Earth Observing One, demonstrating the capability to monitor the nominal operation of the spacecraft under command of an on-board planner, and demonstrating on-board diagnosis of spacecraft failures. Design and development of the experiment, specification and validation of diagnostic scenarios, characterization of performance results and benefits of the model- based approach are presented.

Improving the Interoperability and Usability of NASA Earth Observation Data

NASA Astrophysics Data System (ADS)

Walter, J.; Berrick, S. W.; Murphy, K. J.; Mitchell, A. E.; Tilmes, C.

2014-12-01

NASA's Earth Science Data and Information System Project (ESDIS) is charged with managing, maintaining, and evolving NASA's Earth Observing System Data and Information System (EOSDIS) and is responsible for processing, archiving, and distributing NASA Earth Science data. The system supports a multitude of missions and serves diverse science research and other user communities. While NASA has made, and continues to make, great strides in the discoverability and accessibility of its earth observation data holdings, issues associated with data interoperability and usability still present significant challenges to realizing the full scientific and societal benefits of these data. This concern has been articulated by multiple government agencies, both U.S. and international, as well as other non-governmental organizations around the world. Among these is the White House Office of Science and Technology Policy who, in response, has launched the Big Earth Data Initiative and the Climate Data Initiative to address these concerns for U.S. government agencies. This presentation will describe NASA's approach for addressing data interoperability and usability issues with our earth observation data.

Observation of the Earth by radar

NASA Technical Reports Server (NTRS)

Elachi, C.

1982-01-01

Techniques and applications of radar observation from Earth satellites are discussed. Images processing and analysis of these images are discussed. Also discussed is radar imaging from aircraft. Uses of this data include ocean wave analysis, surface water evaluation, and topographic analysis.

Value of Earth Observation for Risk Mitigation

NASA Astrophysics Data System (ADS)

Pearlman, F.; Shapiro, C. D.; Grasso, M.; Pearlman, J.; Adkins, J. E.; Pindilli, E.; Geppi, D.

2017-12-01

Societal benefits flowing from Earth observation are intuitively obvious as we use the information to assess natural hazards (such as storm tracks), water resources (such as flooding and droughts in coastal and riverine systems), ecosystem vitality and other dynamics that impact the health and economic well being of our population. The most powerful confirmation of these benefits would come from quantifying the impact and showing direct quantitative links in the value chain from data to decisions. However, our ability to identify and quantify those benefits is challenging. The impact of geospatial data on these types of decisions is not well characterized and assigning a true value to the observations on a broad scale across disciplines still remains to be done in a systematic way. This presentation provides the outcomes of a workshop held in October 2017 as a side event of the GEO Plenary that addressed research on economic methodologies for quantification of impacts. To achieve practical outputs during the meeting, the workshop focused on the use and value of Earth observations in risk mitigation including: ecosystem impacts, weather events, and other natural and manmade hazards. Case studies on approaches were discussed and will be part of this presentation. The presentation will also include the exchange of lessons learned and a discussion of gaps in the current understanding of the use and value of earth observation information for risk mitigation.

Determining the Ocean's Role on the Variable Gravity Field on Earth Rotation

NASA Technical Reports Server (NTRS)

Ponte, Rui M.

1999-01-01

A number of ocean models of different complexity have been used to study changes in the oceanic mass field and angular momentum and their relation to the variable Earth rotation and gravity field. Time scales examined range from seasonal to a few days. Results point to the importance of oceanic signals in driving polar motion, in particular the Chandler and annual wobbles. Results also show that oceanic signals have a measurable impact on length-of-day variations. Various circulation features and associated mass signals, including the North Pacific subtropical gyre, the equatorial currents, and the Antarctic Circumpolar Current play a significant role in oceanic angular momentum variability.

Probable Rotation States of Rocket Bodies in Low Earth Orbit

NASA Technical Reports Server (NTRS)

Ojakangas, Gregory W.; Anz-Meador, P.; Cowardin, H.

2012-01-01

In order for Active Debris Removal to be accomplished, it is critically important to understand the probable rotation states of orbiting, spent rocket bodies. As compared to the question of characterizing small unresolved debris, in this problem there are several advantages: (1) objects are of known size, mass, shape and color, (2) they have typically been in orbit for a known period of time, (3) they are large enough that resolved images may be obtainable for verification of predicted orientation, and (4) the dynamical problem is simplified to first order by largely cylindrical symmetry. It is also nearly certain for realistic rocket bodies that internal friction is appreciable in the case where residual liquid or, to a lesser degree, unconsolidated solid fuels exist. Equations of motion have been developed for this problem in which internal friction as well as torques due to solar radiation, magnetic induction, and gravitational gradient are included. In the case of pure cylindrical symmetry, the results are compared to analytical predictions patterned after the standard approach for analysis of symmetrical tops. This is possible because solar radiation and gravitational torques may be treated as conservative. Agreement between results of both methods ensures their mutual validity. For monotone symmetric cylinders, solar radiation torque vanishes if the center of mass resides at the geometric center of the object. Results indicate that in the absence of solar radiation effects, rotation states tend toward an equilibrium configuration in which rotation is about the axis of maximum inertia, with the axis of minimum inertia directed toward the center of the earth. Solar radiation torque introduces a modification to this orientation. The equilibrium state is asymptotically approached within a characteristic timescale given by a simple ratio of relevant characterizing parameters for the body in question. Light curves are simulated for the expected asymptotic final

Rotation Period Determination for 5143 Heracles

NASA Astrophysics Data System (ADS)

Pilcher, Frederick; Briggs, John W.; Franco, Lorenzo; Inasaridze, Raguli Ya.; Krugly, Yurij N.; Molotiv, Igor E.; Klinglesmith, Daniel A., III; Pollock, Joe; Pravec, Petr

2012-07-01

The Earth crossing minor planet 5143 Heracles made in late 2011 its closest approach to Earth since discovery. A consortium of observers found a synodic rotation period near 2.706 hours and amplitude increasing from 0.08 ±0.02 magnitudes at phase angle 20 degrees to 0.18 ±0.03 magnitudes at phase angle 87 degrees, with 3 unequal maxima and minima per cycle. Magnitude parameters H = 14.10 ±0.04 and G = 0.08 ±0.02 are found, and the color index V-R = 0.42 ±0.07. For an asteroid of taxonomic class Q, a suggested albedo pv = 0.20 ±0.05 yields estimated diameter D = 4.5 ±0.7 km. Three possible binary events were recorded, but these are insufficient for binary detection to be secure. Retrograde rotation is suggested.

Coronal Hole Facing Earth

NASA Image and Video Library

2018-05-08

An extensive equatorial coronal hole has rotated so that it is now facing Earth (May 2-4, 2018). The dark coronal hole extends about halfway across the solar disk. It was observed in a wavelength of extreme ultraviolet light. This magnetically open area is streaming solar wind (i.e., a stream of charged particles released from the sun) into space. When Earth enters a solar wind stream and the stream interacts with our magnetosphere, we often experience nice displays of aurora. Videos are available at https://photojournal.jpl.nasa.gov/catalog/PIA00624

Coronal Hole Facing Earth

NASA Image and Video Library

2018-05-15

An extensive equatorial coronal hole has rotated so that it is now facing Earth (May 2-4, 2018). The dark coronal hole extends about halfway across the solar disk. It was observed in a wavelength of extreme ultraviolet light. This magnetically open area is streaming solar wind (i.e., a stream of charged particles released from the sun) into space. When Earth enters a solar wind stream and the stream interacts with our magnetosphere, we often experience nice displays of aurora. https://photojournal.jpl.nasa.gov/catalog/PIA00577

INTEGRATED EARTH OBSERVATIONS: APPLICATION TO AIR QUALITY AND HUMAN HEALTH

EPA Science Inventory

In February 2005, ministers from 60 countries and the European Commission met in Brussels, Belgium to endorse the 10-year plan for a Global Earth Observation System of Systems(GEOSS) prepared by the Group on Earth Observations (GEO), a partnership of nations and international org...

Looking at Earth observation impacts with fresh eyes: a Landsat example

NASA Astrophysics Data System (ADS)

Wu, Zhuoting; Snyder, Greg; Quirk, Bruce; Stensaas, Greg; Vadnais, Carolyn; Babcock, Michael; Dale, Erin; Doucette, Peter

2016-05-01

The U. S. Geological Survey (USGS) initiated the Requirements, Capabilities and Analysis for Earth Observations (RCA-EO) activity in the Land Remote Sensing (LRS) program to provide a structured approach to collect, store, maintain, and analyze user requirements and Earth observing system capabilities information. RCA-EO enables the collection of information on current key Earth observation products, services, and projects, and to evaluate them at different organizational levels within an agency, in terms of how reliant they are on Earth observation data from all sources, including spaceborne, airborne, and ground-based platforms. Within the USGS, RCA-EO has engaged over 500 subject matter experts in this assessment, and evaluated the impacts of more than 1000 different Earth observing data sources on 345 key USGS products and services. This paper summarizes Landsat impacts at various levels of the organizational structure of the USGS and highlights the feedback of the subject matter experts regarding Landsat data and Landsat-derived products. This feedback is expected to inform future Landsat mission decision making. The RCA-EO approach can be applied in a much broader scope to derive comprehensive knowledge of Earth observing system usage and impacts, to inform product and service development and remote sensing technology innovation beyond the USGS.

Near-Earth asteroids: Observer alert network and physical observations

NASA Technical Reports Server (NTRS)

Davis, Donald R.; Chapman, Clark R.

1992-01-01

This project strives to obtain physical observations on newly discovered Near-Earth Objects (NEO's) in order to provide fundamental data needed to assess the resources available in the population. The goal is acquiring data on all objects brighter than magnitude V= 17.0. To accomplish this, an electronic mail alert and observer information service that informs observers around the world as to the status of physical observations on currently observable NEO's was established. Such data is also acquired ourselves through a cooperative program with European colleagues that uses telescopes on La Palma to obtain spectra of NEO's and through observations made from a local telescope on Tumamoc Hill. This latter telescope has the advantage that large amounts of observing time are available, so that whenever a new NEO's discovered, we can be assured of getting time to observe it.

Impacts of Earth rotation parameters on GNSS ultra-rapid orbit prediction: Derivation and real-time correction

NASA Astrophysics Data System (ADS)

Wang, Qianxin; Hu, Chao; Xu, Tianhe; Chang, Guobin; Hernández Moraleda, Alberto

2017-12-01

Analysis centers (ACs) for global navigation satellite systems (GNSSs) cannot accurately obtain real-time Earth rotation parameters (ERPs). Thus, the prediction of ultra-rapid orbits in the international terrestrial reference system (ITRS) has to utilize the predicted ERPs issued by the International Earth Rotation and Reference Systems Service (IERS) or the International GNSS Service (IGS). In this study, the accuracy of ERPs predicted by IERS and IGS is analyzed. The error of the ERPs predicted for one day can reach 0.15 mas and 0.053 ms in polar motion and UT1-UTC direction, respectively. Then, the impact of ERP errors on ultra-rapid orbit prediction by GNSS is studied. The methods for orbit integration and frame transformation in orbit prediction with introduced ERP errors dominate the accuracy of the predicted orbit. Experimental results show that the transformation from the geocentric celestial references system (GCRS) to ITRS exerts the strongest effect on the accuracy of the predicted ultra-rapid orbit. To obtain the most accurate predicted ultra-rapid orbit, a corresponding real-time orbit correction method is developed. First, orbits without ERP-related errors are predicted on the basis of ITRS observed part of ultra-rapid orbit for use as reference. Then, the corresponding predicted orbit is transformed from GCRS to ITRS to adjust for the predicted ERPs. Finally, the corrected ERPs with error slopes are re-introduced to correct the predicted orbit in ITRS. To validate the proposed method, three experimental schemes are designed: function extrapolation, simulation experiments, and experiments with predicted ultra-rapid orbits and international GNSS Monitoring and Assessment System (iGMAS) products. Experimental results show that using the proposed correction method with IERS products considerably improved the accuracy of ultra-rapid orbit prediction (except the geosynchronous BeiDou orbits). The accuracy of orbit prediction is enhanced by at least 50

New Earth Observation Capabilities For The Commercial Sector

NASA Technical Reports Server (NTRS)

Stefanov, William L.

2017-01-01

Earth observation data collected from orbital remote sensing systems are becoming increasingly critical to the short- and long-term operations of many commercial industries including agriculture, energy exploration, environmental management, transportation, and urban planning and operations. In this panel, I will present an overview of current and planned NASA remote sensing systems for Earth observation with relevance to commercial and industrial applications. Special emphasis will be given to the International Space Station (ISS) as a platform for both commercial technology demonstration/development and operational data collection through the ISS National Laboratory.

Venus - Atmospheric rotation.

NASA Technical Reports Server (NTRS)

Scott, A. H.; Reese, E. J.

1972-01-01

Photographs of Venus taken in ultraviolet light from Sept. 29, 1963, to May 29, 1971, indicate a general planet-wide circulation in the upper atmosphere of that planet having velocities which varied with time from -87 to -127m/sec at the equator. Positional measurements on 67 pairs of photographs which show the recurrence of similar patterns after intervals of one to three rotations suggest an asymmetric bimodal distribution of these velocities. The ultraviolet markings appear to be randomly distributed and quite ephemeral in nature, rarely enduring in a recognizable pattern for more than 20 days and usually much less. Attention is directed to an apparent but fictitious mean sidereal rotation period of approximately 4.06 days derived from observations which are made at a single station and span many months or years. Under such conditions this fictitious value for the rotation period is produced by the commensurability of the one-day period of earth and the assumed four-day period of the atmosphere of Venus.

Earth Observation

NASA Image and Video Library

2014-07-19

ISS040-E-070412 (19 July 2014) --- One of the Expedition 40 crew members aboard the Earth-orbiting International Space Station recorded this July 19 panorama featuring wildfires which are plaguing the Northwest and causing widespread destruction. (Note: south is at the top of the frame). The orbital outpost was flying 223 nautical miles above Earth at the time of the photo. Parts of Oregon and Washington are included in the scene. Mt. Jefferson, Three Sisters and Mt. St. Helens are all snow-capped and visible in the photo, and the Columbia River can also be delineated.

Earth observation

NASA Image and Video Library

2014-09-04

ISS040-E-129950 (4 Sept. 2014) --- In this photograph. taken by one of the Expedition 40 crew members aboard the Earth-orbiting International Space Station, the orange spot located in the very center is the sun, which appears to be sitting on Earth's limb. At far right, a small bright spot is believed to be a reflection from somewhere in the camera system or something on the orbital outpost. When the photographed was exposed, the orbital outpost was flying at an altutude of 226 nautical miles above a point near French Polynesia in the Pacific Ocean.

Sensing Planet Earth - Chalmers' MOOCs on Earth observation

NASA Astrophysics Data System (ADS)

Hobiger, Thomas; Stöhr, Christian; Murtagh, Donal; Forkman, Peter; Galle, Bo; Mellquist, Johan; Soja, Maciej; Berg, Anders; Carvajal, Gisela; Eriksson, Leif; Haas, Rüdiger

2016-04-01

An increasing number of universities around the globe produce and conduct Massive Open Online Courses (MOOCs). In the beginning of 2016, Chalmers University of Technology ran two MOOCs on the topic of Earth observations on the edX platform. Both four week long courses were at introductory level and covered topics related to solid Earth, atmosphere, biosphere, hydrosphere and cryosphere. It was discussed how one can measure and trace global change and use remote sensing tools for disaster monitoring. Research has attempted to assess the learners' motivations to participate in MOOCs, but there is a need for further case studies about motivations, opportunities and challenges for teachers engaging in MOOC development. In our presentation, we are going to report about the experiences gained from both the MOOC production and the actual course run from the instructors' perspective. After brief introduction to MOOCs in general and at Chalmers in particular, we share experiences and challenges of developing lecture and assessment material, the video production and coordination efforts between and within different actors involved in the production process. Further, we reflect upon the actual run of the course including course statistics and feedback from the learners. We discuss issues such as learner activation and engagement with the material, teacher-learner and student-student interaction as well as the scalability of different learning activities. Finally, we will present our lessons-learned and conclusions on the applicability of MOOCs in the field of Earth science teaching.

Utilizing Earth Observations for Societal Issues

NASA Technical Reports Server (NTRS)

Habib, Shahid

2010-01-01

Over the last four decades a tremendous progress has been made in the Earth science space-based remote sensing observations, technologies and algorithms. Such advancements have improved the predictability by providing lead-time and accuracy of forecast in weather, climate, natural hazards, and natural resources. It has further reduced or bounded the overall uncertainties by partially improving our understanding of planet Earth as an integrated system that is governed by non-linear and chaotic behavior. Many countries such as the US, European Community, Japan, China, Russia, India has and others have invested billions of dollars in developing and launching space-based assets in the low earth (LEO) and geostationary (GEO) orbits. However, the wealth of this scientific knowledge that has potential of extracting monumental socio-economic benefits from such large investments have been slow in reaching the public and decision makers. For instance, there are a number of areas such as water resources and availability, energy forecasting, aviation safety, agricultural competitiveness, disaster management, air quality and public health, which can directly take advantage. Nevertheless, we all live in a global economy that depends on access to the best available Earth Science information for all inhabitants of this planet. This presentation discusses a process to transition Earth science data and products for societal needs including NASA's experience in achieving such objectives. It is important to mention that there are many challenges and issues that pertain to a number of areas such as: (1) difficulties in making a speedy transition of data and information from observations and models to relevant Decision Support Systems (DSS) or tools, (2) data and models inter-operability issues, (3) limitations of spatial, spectral and temporal resolution, (4) communication limitations as dictated by the availability of image processing and data compression techniques. Additionally, the

Conceptual Research of Lunar-based Earth Observation for Polar Glacier Motion

NASA Astrophysics Data System (ADS)

Ruan, Zhixing; Liu, Guang; Ding, Yixing

2016-07-01

The ice flow velocity of glaciers is important for estimating the polar ice sheet mass balance, and it is of great significance for studies into rising sea level under the background of global warming. However so far the long-term and global measurements of these macro-scale motion processes of the polar glaciers have hardly been achieved by Earth Observation (EO) technique from the ground, aircraft or satellites in space. This paper, facing the demand for space technology for large-scale global environmental change observation,especially the changes of polar glaciers, and proposes a new concept involving setting up sensors on the lunar surface and using the Moon as a platform for Earth observation, transmitting the data back to Earth. Lunar-based Earth observation, which enables the Earth's large-scale, continuous, long-term dynamic motions to be measured, is expected to provide a new solution to the problems mentioned above. According to the pattern and characteristics of polar glaciers motion, we will propose a comprehensive investigation of Lunar-based Earth observation with synthetic aperture radar (SAR). Via theoretical modeling and experimental simulation inversion, intensive studies of Lunar-based Earth observation for the glacier motions in the polar regions will be implemented, including the InSAR basics theory, observation modes of InSAR and optimization methods of their key parameters. It will be of a great help to creatively expand the EO technique system from space. In addition, they will contribute to establishing the theoretical foundation for the realization of the global, long-term and continuous observation for the glacier motion phenomena in the Antarctic and the Arctic.

Correction and update to 'The earth's C21 and S21 gravity coefficients and the rotation of the core'

NASA Technical Reports Server (NTRS)

Wahr, John

1990-01-01

Wahr (1987) used satellite constraints on C21 and S21 (the spherical harmonic coefficients of the earth's external gravitational potential) to infer certain properties of the core and core/mantle boundary. It is shown here, contrary to the claim by Wahr, that it is not possible to use C21 and S21 to placed bounds on the core's products of inertia. As a result, Wahr's constraints on the l = 2, m = 1 components of the core/mantle boundary topography and on the angular orientation of the inner core with respect to the earth's rotation vector are not justified. On the other hand, Wahr's conclusions about the time-averaged torque between the core and mantle and the resulting implications for the l = 2, m = 1 components of fluid pressure at the top of the core can be strengthened. Wahr's conclusions about the mean rotational flow in the core are unaltered.

The space shuttle payload planning working groups. Volume 7: Earth observations

NASA Technical Reports Server (NTRS)

1973-01-01

The findings of the Earth Observations working group of the space shuttle payload planning activity are presented. The objectives of the Earth Observation experiments are: (1) establishment of quantitative relationships between observable parameters and geophysical variables, (2) development, test, calibration, and evaluation of eventual flight instruments in experimental space flight missions, (3) demonstration of the operational utility of specific observation concepts or techniques as information inputs needed for taking actions, and (4) deployment of prototype and follow-on operational Earth Observation systems. The basic payload capability, mission duration, launch sites, inclinations, and payload limitations are defined.

Data base on physical observations of near-Earth asteroids and establishment of a network to coordinate observations of newly discovered near-Earth asteroids

NASA Technical Reports Server (NTRS)

Davis, D. R.; Chapman, C. R.; Campins, H.

1990-01-01

This program consists of two tasks: (1) development of a data base of physical observations of near-earth asteroids and establishment of a network to coordinate observations of newly discovered earth-approaching asteroids; and (2) a simulation of the surface of low-activity comets. Significant progress was made on task one and, and task two was completed during the period covered by this progress report.

Observation and integrated Earth-system science: A roadmap for 2016–2025

DOE Office of Scientific and Technical Information (OSTI.GOV)

Simmons, Adrian; Fellous, Jean-Louis; Ramaswamy, V.

This report is the response to a request by the Committee on Space Research of the International Council for Science to prepare a roadmap on observation and integrated Earth-system science for the coming ten years. Its focus is on the combined use of observations and modelling to address the functioning, predictability and projected evolution of interacting components of the Earth system on timescales out to a century or so. It discusses how observations support integrated Earth-system science and its applications, and identifies planned enhancements to the contributing observing systems and other requirements for observations and their processing. All types ofmore » observation are considered, but emphasis is placed on those made from space. The origins and development of the integrated view of the Earth system are outlined, noting the interactions between the main components that lead to requirements for integrated science and modelling, and for the observations that guide and support them. What constitutes an Earth-system model is discussed. Summaries are given of key cycles within the Earth system. The nature of Earth observation and the arrangements for international coordination essential for effective operation of global observing systems are introduced. Instances are given of present types of observation, what is already on the roadmap for 2016–2025 and some of the issues to be faced. Observations that are organized on a systematic basis and observations that are made for process understanding and model development, or other research or demonstration purposes, are covered. Specific accounts are given for many of the variables of the Earth system. The current status and prospects for Earth-system modelling are summarized. The evolution towards applying Earth-system models for environmental monitoring and prediction as well as for climate simulation and projection is outlined. General aspects of the improvement of models, whether through refining the

Copernicus: a quantum leap in Earth Observation

NASA Astrophysics Data System (ADS)

Aschbacher, Josef

2015-04-01

Copernicus is the most ambitious, most comprehensive Earth observation system world-wide. It aims at giving decision-makers better information to act upon, at global, continental, national and regional level. The European Union (EU) leads the overall programme, while the European Space Agency (ESA) coordinates the space component. Similar to meteorology, satellite data is combined with data from airborne and ground sensors to provide a holistic view of the state of the planet. All these data are fed into a range of thematic information services designed to benefit the environment and to support policy-makers and other stakeholders to make decisions, coordinate policy areas, and formulate strategies relating to the environment. Moreover, the data will also be used for predicting future climate trends. Never has such a comprehensive Earth-observation based system been in place before. It will be fully integrated into an informed decision making process, thus enabling economic and social benefits through better access to information globally. A key feature of Copernicus is the free and open data policy of the Sentinel satellite data. This will enable that Earth observation based information enters completely new domains of daily life. High quality, regularly updated satellite observations become available for basically everyone. To ensure universal access new ground segment and data access concepts need to be developed. As more data are made available, better decisions can made, more business will be created and science and research can be achieved through the upcoming Sentinel data.

Sensor requirements for Earth and planetary observations

NASA Technical Reports Server (NTRS)

Chahine, Moustafa T.

1990-01-01

Future generations of Earth and planetary remote sensing instruments will require extensive developments of new long-wave and very long-wave infrared detectors. The upcoming NASA Earth Observing System (EOS) will carry a suite of instruments to monitor a wide range of atmospheric and surface parameters with an unprecedented degree of accuracy for a period of 10 to 15 years. These instruments will observe Earth over a wide spectral range extending from the visible to nearly 17 micrometers with a moderate to high spectral and spacial resolution. In addition to expected improvements in communication bandwidth and both ground and on-board computing power, these new sensor systems will need large two-dimensional detector arrays. Such arrays exist for visible wavelengths and, to a lesser extent, for short wavelength infrared systems. The most dramatic need is for new Long Wavelength Infrared (LWIR) and Very Long Wavelength Infrared (VLWIR) detector technologies that are compatible with area array readout devices and can operate in the temperature range supported by long life, low power refrigerators. A scientific need for radiometric and calibration accuracies approaching 1 percent translates into a requirement for detectors with excellent linearity, stability and insensitivity to operating conditions and space radiation. Current examples of the kind of scientific missions these new thermal IR detectors would enhance in the future include instruments for Earth science such as Orbital Volcanological Observations (OVO), Atmospheric Infrared Sounder (AIRS), Moderate Resolution Imaging Spectrometer (MODIS), and Spectroscopy in the Atmosphere using Far Infrared Emission (SAFIRE). Planetary exploration missions such as Cassini also provide examples of instrument concepts that could be enhanced by new IR detector technologies.

The Earth Observing System Terra Mission

NASA Technical Reports Server (NTRS)

Kaufman, Yoram J.

2000-01-01

Langley's remarkable solar and lunar spectra collected from Mt. Whitney inspired Arrhenius to develop the first quantitative climate model in 1896. After the launch in Dec. 16 1999, NASA's Earth Observing AM Satellite (EOS-Terra) will repeat Langley's experiment, but for the entire planet, thus pioneering a wide array of calibrated spectral observations from space of the Earth System. Conceived in response to real environmental problems, EOS-Terra, in conjunction with other international satellite efforts, will fill a major gap in current efforts by providing quantitative global data sets with a resolution smaller than 1 km on the physical, chemical and biological elements of the earth system. Thus, like Langley's data, EOS-Terra can revolutionize climate research by inspiring a new generation of climate system models and enable us to assess the human impact on the environment. In the talk I shall review the historical perspective of the Terra mission and the key new elements of the mission. We expect to have some first images that demonstrate the most innovative capability from EOS Terra: MODIS - 1.37 microns cirrus channel; 250 m daily cover for clouds and vegetation change; 7 solar channels for land and aerosol; new fire channels; Chlorophyll fluorescence; MISR - 9 multi angle views of clouds and vegetation; MOPITT - Global CO maps and CH4 maps; ASTER - Thermal channels for geological studies with 15-90 m resolution.

The early Earth Observing System reference handbook: Earth Science and Applications Division missions, 1990-1997

NASA Technical Reports Server (NTRS)

1990-01-01

Prior to the launch of the Earth Observing System (EOS) series, NASA will launch and operate a wide variety of new earth science satellites and instruments, as well as undertake several efforts collecting and using the data from existing and planned satellites from other agencies and nations. These initiatives will augment the knowledge base gained from ongoing Earth Science and Applications Division (ESAD) programs. This volume describes three sets of ESAD activities -- ongoing exploitation of operational satellite data, research missions with upcoming launches between now and the first launch of EOS, and candidate earth probes.

The Operations Security Concept for Future ESA Earth Observation Missions

NASA Astrophysics Data System (ADS)

Fischer, D.; Bargellini, P.; Merri, M.

2008-08-01

Next-generation European earth observation missions will play a critical role in public safety and security infrastructures. This makes it necessary for ESA to protect the communication infrastructure of these missions in order to guarantee their service availability. In this paper, we discuss the development process for a generic earth observation security concept. This concept has been developed as part of a GMES Flight Operation Segment security study with the objective to analyse and select a number of high level security requirements for the missions. Further, we studied the impact of an implementation for these requirements on the operational infrastructure of current earth observation missions.

Earth Science Observations from the International Space Station: An Overview (Invited)

NASA Astrophysics Data System (ADS)

Kaye, J. A.

2013-12-01

The International Space Station (ISS) provides a unique and valuable platform for observing the Earth. With its mid-inclination (~51 degree) orbit, it provides the opportunity to view most of the Earth, with data acquisition possible over a full range of local times, in an orbit that nicely complements the polar sun-synchronous orbits used for much of space-based Earth observation, and can draw on a heritage of mid-inclination observations from both free flying satellites and the Space Shuttle program. The ISS, including its component observing modules supplied by NASA's international partners, can provide needed resources and viewing opportunities by a broad range of Earth-viewing scientific instruments. In this talk, the overall picture of Earth viewing from ISS will be presented, with examples from a range of past, current, and projected sensors being shared; talks on the ISS implementation for a subset of current and projected payload will be presented in individual talks presented by their their respective teams.

Earth Observation

NASA Image and Video Library

2010-08-23

ISS024-E-016042 (23 Aug. 2010) --- This night time view captured by one of the Expedition 24 crew members aboard the International Space Station some 220 miles above Earth is looking southward from central Romania over the Aegean Sea toward Greece and it includes Thessaloniki (near center), the larger bright mass of Athens (left center), and the Macedonian capital of Skopje (lower right). Center point coordinates of the area pictured are 46.4 degrees north latitude and 25.5 degrees east longitude. The picture was taken in August and was physically brought back to Earth on a disk with the return of the Expedition 25 crew in November 2010.

Rigidly rotating zero-angular-momentum observer surfaces in the Kerr spacetime

NASA Astrophysics Data System (ADS)

Frolov, Andrei V.; Frolov, Valeri P.

2014-12-01

A stationary observer in the Kerr spacetime has zero angular momentum if their angular velocity ω has a particular value, which depends on the position of the observer. Worldlines of such zero-angular-momentum observers (ZAMOs) with the same value of the angular velocity ω form a three-dimensional surface, which has the property that the Killing vectors generating time translation and rotation are tangent to it. We call such a surface a rigidly rotating ZAMO surface. This definition allows for a natural generalization to the surfaces inside the black hole, where ZAMO trajectories formally become spacelike. A general property of such a surface is that there exist linear combinations of the Killing vectors with constant coefficients which make them orthogonal on it. In this paper we discuss properties of the rigidly rotating ZAMO surfaces both outside and inside the black hole and the relevance of these objects to a couple of interesting physical problems.

Earth observation taken by the Expedition 43 crew

NASA Image and Video Library

2015-04-26

ISS043E142265 (04/26/2015) --- NASA astronaut Scott Kelly on the International Space Station Apr.26, 2015 tweeted this image out of an Earth observation as part of his Space Geo contest "name this location" with this remark and clue: "This frozen body of water is the world's oldest (25 million years) and deepest basin on Earth. Name it!"

Spectrally resolved interferometric observations of α Cephei and physical modeling of fast rotating stars

NASA Astrophysics Data System (ADS)

Delaa, O.; Zorec, J.; Domiciano de Souza, A.; Mourard, D.; Perraut, K.; Stee, Ph.; Frémat, Y.; Monnier, J.; Kraus, S.; Che, X.; Bério, Ph.; Bonneau, D.; Clausse, J. M.; Challouf, M.; Ligi, R.; Meilland, A.; Nardetto, N.; Spang, A.; McAlister, H.; ten Brummelaar, T.; Sturmann, J.; Sturmann, L.; Turner, N.; Farrington, C.; Goldfinger, P. J.

2013-07-01

Context. When a given observational quantity depends on several stellar physical parameters, it is generally very difficult to obtain observational constraints for each of them individually. Therefore, we studied under which conditions constraints for some individual parameters can be achieved for fast rotators, knowing that their geometry is modified by the rapid rotation which causes a non-uniform surface brightness distribution. Aims: We aim to study the sensitivity of interferometric observables on the position angle of the rotation axis (PA) of a rapidly rotating star, and whether other physical parameters can influence the determination of PA, and also the influence of the surface differential rotation on the determination of the β exponent in the gravity darkening law that enters the interpretation of interferometric observations, using α Cep as a test star. Methods: We used differential phases obtained from observations carried out in the Hα absorption line of α Cep with the VEGA/CHARA interferometer at high spectral resolution, R = 30 000 to study the kinematics in the atmosphere of the star. Results: We studied the influence of the gravity darkening effect (GDE) on the determination of the PA of the rotation axis of α Cep and determined its value, PA = -157-10°+17°. We conclude that the GDE has a weak influence on the dispersed phases. We showed that the surface differential rotation can have a rather strong influence on the determination of the gravity darkening exponent. A new method of determining the inclination angle of the stellar rotational axis is suggested. We conclude that differential phases obtained with spectro-interferometry carried out on the Hα line can in principle lead to an estimate of the stellar inclination angle i. However, to determine both i and the differential rotation parameter α, lines free from the Stark effect and that have collision-dominated source functions are to be preferred.

EOS Reference Handbook 1999: A Guide to NASA's Earth Science Enterprise and the Earth Observing System

NASA Technical Reports Server (NTRS)

King, M. D. (Editor); Greenstone, R. (Editor)

2000-01-01

The content of this handbook includes Earth Science Enterprise; The Earth Observing System; EOS Data and Information System (EOSDIS); Data and Information Policy; Pathfinder Data Sets; Earth Science Information Partners and the Working Prototype-Federation; EOS Data Quality: Calibration and Validation; Education Programs; International Cooperation; Interagency Coordination; Mission Elements; EOS Instruments; EOS Interdisciplinary Science Investigations; and Points-of-Contact.

Developing methods of determining unknown roational periods of asteroids via observations of (3122) Florence by the Harvard Observing Project

NASA Astrophysics Data System (ADS)

Abrams, Natasha Sarah; Bieryla, Allyson; Gomez, Sebastian; Huang, Jane; Lewis, John; Todd, Zoe; Alam, Munazza; Carmichael, Theron; Garrison, Lehman H.; Weaver, Ian; Chen, Chen; McGruder, Chima; Medina, Amber

2018-06-01

(3122) Florence is an asteroid that made the headlines with its close approach to Earth in late 2017. It is one of the biggest and brightest near-Earth asteroids that has been discovered and it has recently been found to have two moons. By observing the light reflected off an asteroid, we can measure its brightness over time and determine the rotational period of the asteroid. An asteroid’s rotational period can reveal information about its physical characteristics, such as its shape, and further our knowledge about processes that contribute to asteroid rotation in general. The Harvard Observing Project (HOP) is an initiative that allows undergraduates to learn about observational astronomy and take part in formal data collection and analysis. Over the course of the fall 2017 semester, HOP obtained four multi-hour, continuous observations in the R-band of the asteroid using the Harvard University 16-inch Clay Telescope. In our analysis, we reduced the images and performed astrometry and photometry on the data. The asteroid’s light curve was produced using AstroImageJ and we used the Python package gatspy to determine its rotational period. We found the rotational period to be 2.22 hours +/- 0.25, which agrees with the known rotational period of 2.3580 hours +/- 0.0002. This spring 2018 semester we are applying our methods to data collected on asteroids with unknown rotational periods and plan to present our findings.

Earth Observations: Experiences from Various Communication Strategies

NASA Astrophysics Data System (ADS)

Lilja Bye, Bente

2015-04-01

With Earth observations and the Group of Earth Observations as the common thread, a variety of communication strategies have been applied showcasing the use of Earth observations in geosciences such as climate change, natural hazards, hydrology and more. Based on the experiences from these communication strategies, using communication channels ranging from popular articles in established media, video production, event-based material and social media, lessons have been learned both with respect to the need of capacity, skills, networks, and resources. In general it is not difficult to mobilize geoscientists willing to spend some time on outreach activities. Time for preparing and training is however scarce among scientists. In addition, resources to cover the various aspects of professional science outreach is far from abundant. Among the challenges is the connection between the scientific networks and media channels. Social media competence and capacity are also issues that needs to be addressed more explicitly and efficiently. An overview of the experiences from several types of outreach activities will be given along with some input on possible steps towards improved communication strategies. Steady development of science communication strategies continuously integrating trainging of scientists in use of new outreach tools such as web technology and social innovations for more efficient use of limited resources will remain an issue for the scientific community.

Rotational Dynamics of Inactive Satellites as a Result of the YORP Effect

NASA Astrophysics Data System (ADS)

Albuja, Antonella A.

Observations of inactive satellites in Earth orbit show that these objects are generally rotating, some with very fast rotation rates. In addition, observations indicate that the rotation rate at which defunct satellites spin tends to evolve over time. However, the cause for this behavior is unknown. The observed secular change in the spin rate and spin axis orientation of asteroids is known to be caused by the Yarkovsky-O'Keefe-Radzievskii-Paddack (YORP) effect, which results in a torque that is created from reflected thermal energy and sunlight from the surface of an asteroid. This thesis explores the effect of YORP on defunct satellites in Earth orbit and offers this as a potential cause for the observed rotation states of inactive satellites. In this work, several different satellite models are developed to represent inactive satellites in Geostationary Earth Orbit (GEO). The evolution of the spin rate and obliquity for each satellite is then explored using Euler's equations of motion as well as spin and year averaged dynamics. This results in the dynamics being analyzed to understand the secular changes that occur, as well as the variations that result from short period terms over the course of a year. Some of the model satellites have asymmetric geometries, leading to the classical YORP effect as originally formulated for asteroids. One model satellite is geometrically symmetric, but relies on mass distribution asymmetry to generate the YORP effect. Because the YORP effect is directly dependent on geometric, optical and thermal properties of the satellite, varying these parameters can lead to different long-term rotational behavior. A sensitivity study is done by varying these parameters and analyzing its effect on the long-term dynamics of a satellite. Additionally, available observation data of inactive GEO satellites are used to estimate the YORP torque acting on those bodies. A comparison between this torque and the expected torque on a defunct satellite

Crew Earth Observations: Twelve Years of Documenting Earth from the International Space Station

NASA Technical Reports Server (NTRS)

Evans, Cynthia A.; Stefanov, William L.; Willis, Kimberley; Runco, Susan; Wilkinson, M. Justin; Dawson, Melissa; Trenchard, Michael

2012-01-01

The Crew Earth Observations (CEO) payload was one of the initial experiments aboard the International Space Station, and has been continuously collecting data about the Earth since Expedition 1. The design of the experiment is simple: using state-of-the-art camera equipment, astronauts collect imagery of the Earth's surface over defined regions of scientific interest and also document dynamic events such as storms systems, floods, wild fires and volcanic eruptions. To date, CEO has provided roughly 600,000 images of Earth, capturing views of features and processes on land, the oceans, and the atmosphere. CEO data are less rigorously constrained than other remote sensing data, but the volume of data, and the unique attributes of the imagery provide a rich and understandable view of the Earth that is difficult to achieve from the classic remote sensing platforms. In addition, the length-of-record of the imagery dataset, especially when combined with astronaut photography from other NASA and Russian missions starting in the early 1960s, provides a valuable record of changes on the surface of the Earth over 50 years. This time period coincides with the rapid growth of human settlements and human infrastructure.

Quantifying Atmospheric Moist Processes from Earth Observations. Really?

NASA Astrophysics Data System (ADS)

Shepson, P. B.; Cambaliza, M. O. L.; Salmon, O. E.; Heimburger, A. M. F.; Davis, K. J.; Lauvaux, T.; McGowan, L. E.; Miles, N.; Richardson, S.; Sarmiento, D. P.; Hardesty, M.; Karion, A.; Sweeney, C.; Iraci, L. T.; Hillyard, P. W.; Podolske, J. R.; Gurney, K. R.; Patarasuk, R.; Razlivanov, I. N.; Song, Y.; O'Keeffe, D.; Turnbull, J. C.; Vimont, I.; Whetstone, J. R.; Possolo, A.; Prasad, K.; Lopez-Coto, I.

2014-12-01

The amount of water in the Earth's atmosphere is tiny compared to all other sources of water on our planet, fresh or otherwise. However, this tiny amount of water is fundamental to most aspects of human life. The tiny amount of water that cycles from the Earth's surface, through condensation into clouds in the atmosphere returning as precipitation falling is not only natures way of delivering fresh water to land-locked human societies but it also exerts a fundamental control on our climate system producing the most important feedbacks in the system. The representation of these processes in Earth system models contain many errors that produce well now biases in the hydrological cycle. Surprisingly the parameterizations of these important processes are not well validated with observations. Part of the reason for this situation stems from the fact that process evaluation is difficult to achieve on the global scale since it has commonly been assumed that the static observations available from snap-shots of individual parameters contain little information on processes. One of the successes of the A-Train has been the development of multi-parameter analysis based on the multi-sensor data produced by the satellite constellation. This has led to new insights on how water cycles through the Earth's atmosphere. Examples of these insights will be highlighted. It will be described how the rain formation process has been observed and how this has been used to constrain this process in models, with a huge impact. How these observations are beginning to reveal insights on deep convection and examples of the use these observations applied to models will also be highlighted as will the effects of aerosol on clouds on radiation.

Quantifying Atmospheric Moist Processes from Earth Observations. Really?

NASA Astrophysics Data System (ADS)

Stephens, G. L.

2015-12-01

The amount of water in the Earth's atmosphere is tiny compared to all other sources of water on our planet, fresh or otherwise. However, this tiny amount of water is fundamental to most aspects of human life. The tiny amount of water that cycles from the Earth's surface, through condensation into clouds in the atmosphere returning as precipitation falling is not only natures way of delivering fresh water to land-locked human societies but it also exerts a fundamental control on our climate system producing the most important feedbacks in the system. The representation of these processes in Earth system models contain many errors that produce well now biases in the hydrological cycle. Surprisingly the parameterizations of these important processes are not well validated with observations. Part of the reason for this situation stems from the fact that process evaluation is difficult to achieve on the global scale since it has commonly been assumed that the static observations available from snap-shots of individual parameters contain little information on processes. One of the successes of the A-Train has been the development of multi-parameter analysis based on the multi-sensor data produced by the satellite constellation. This has led to new insights on how water cycles through the Earth's atmosphere. Examples of these insights will be highlighted. It will be described how the rain formation process has been observed and how this has been used to constrain this process in models, with a huge impact. How these observations are beginning to reveal insights on deep convection and examples of the use these observations applied to models will also be highlighted as will the effects of aerosol on clouds on radiation.

Earth Observation

NASA Image and Video Library

2014-07-19

ISS040-E-070439 (19 July 2014) --- One of the Expedition 40 crew members aboard the Earth-orbiting International Space Station recorded this July 19 image of wildfires which are plaguing the Northwest and causing widespread destruction. The orbital outpost was flying 223 nautical miles above a point on Earth located at 48.0 degrees north latitude and 116.9 degrees west longitude when the image was exposed. The state of Washington is especially affected by the fires, many of which have been blamed on lightning. This particular fire was part of the Carlton Complex Fire, located near the city of Brewster in north central Washington. The reservoir visible near the center of the image is Banks Lake.

Earth Observations taken by Expedition 47 Crewmember.

NASA Image and Video Library

2016-03-26

ISS047e022293 (03/26/2016) --- This Earth Observation image from the International Space Station is of a large extinct volcano in the lower southwest African Brukkaros Mountain in the country of Namibia.

Valley Fever: Earth Observations for Risk Reduction

NASA Astrophysics Data System (ADS)

Sprigg, W. A.

2012-12-01

Advances in satellite Earth observation systems, numerical weather prediction, and dust storm modeling yield new tools for public health warnings, advisories and epidemiology of illnesses associated with airborne desert dust. Valley Fever, endemic from California through the US/Mexico border region into Central and South America, is triggered by inhalation of soil-dwelling fungal spores. The path from fungal growth to airborne threat depends on environmental conditions observable from satellite. And space-based sensors provide initial conditions for dust storm forecasts and baselines for the epidemiology of Valley Fever and other dust-borne aggravation of respiratory and cardiovascular disease. A new Pan-American Center for the World Meteorological Organization Sand and Dust Storm Warning Advisory and Assessment System creates an opportunity to advance Earth science applications in public health.

STS-59 crewmembers in training for onboard Earth observations

NASA Technical Reports Server (NTRS)

1993-01-01

The six astronauts in training for the STS-59 mission are shown onboard Earth observations tips by Justin Wilkinson (standing, foreground) of the Space Shuttle Earth Observations Project (SSEOP) group. Astronaut Sidney M. Gutierrez, mission commander, is at center on the left side of the table. Others, left to right, are Astronauts Kevin P. Chilton, pilot; Jerome (Jay) Apt and Michael R.U. (Rich) Clifford, both mission specialists; Linda M. Godwin, payload commander; and Thomas D. Jones, mission specialist.

Deuterium on Venus: Observations from Earth

NASA Technical Reports Server (NTRS)

Lutz, Barry L.; Debergh, C.; Bezard, B.; Owen, T.; Crisp, D.; Maillard, J.-P.

1991-01-01

In view of the importance of the deuterium-to-hydrogen ratio in understanding the evolutionary scenario of planetary atmospheres and its relationship to understanding the evolution of our own Earth, we undertook a series of observations designed to resolve previous observational conflicts. We observed the dark side of Venus in the 2.3 micron spectral region in search of both H2O and HDO, which would provide us with the D/H ratio in Venus' atmosphere. We identified a large number of molecular lines in the region, belonging to both molecules, and, using synthetic spectral techniques, obtained mixing ratios of 34 plus or minus 10 ppm and 1.3 plus or minus 0.2 ppm for H2O and HDO, respectively. These mixing ratios yield a D/H ratio for Venus of D/H equals 1.9 plus or minus 0.6 times 10 (exp 12) and 120 plus or minus 40 times the telluric ratio. Although the detailed interpretation is difficult, our observations confirm that the Pioneer Venus Orbiter results and establish that indeed Venus had a period in its early history in which it was very wet, perhaps not unlike the early wet period that seems to have been present on Mars, and that, in contrast to Earth, lost much of its water over geologic time.

Rotational Seismology: AGU Session, Working Group, and Website

USGS Publications Warehouse

Lee, William H.K.; Igel, Heiner; Todorovska, Maria I.; Evans, John R.

2007-01-01

. Igel, W.H.K. Lee, and M. Todorovska during the 2006 AGU Fall Meeting. The goal of this session was to discuss rotational sensors, observations, modeling, theoretical aspects, and potential applications of rotational ground motions. The session was accompanied by the inauguration of an International Working Group on Rotational Seismology (IWGoRS) which aims to promote investigations of all aspects of rotational motions in seismology and their implications for related fields such as earthquake engineering, geodesy, strong-motion seismology, and tectonics, as well as to share experience, data, software, and results in an open Web-based environment. The primary goal of this article is to make the Earth Science Community aware of the emergence of the field of rotational seismology.

Korea Earth Observation Satellite Program

NASA Astrophysics Data System (ADS)

Baek, Myung-Jin; Kim, Zeen-Chul

via Korea Aerospace Research Institute (KARI) as the prime contractor in the area of Korea earth observation satellite program to enhance Korea's space program development capability. In this paper, Korea's on-going and future earth observation satellite programs are introduced: KOMPSAT- 1 (Korea Multi Purpose Satellite-1), KOMPSAT-2 and Communication, Broadcasting and Meteorological Satellite (CBMS) program. KOMPSAT-1 satellite successfully launched in December 1999 with Taurus launch vehicle. Since launch, KOMPSAT-1 is downlinking images of Korea Peninsular every day. Until now, KOMPSAT-1 has been operated more than 2 and half years without any major hardware malfunction for the mission operation. KOMPSAT-1 payload has 6.6m panchromatic spatial resolution at 685 km on-orbit and the spacecraft bus had NASA TOMS-EP (Total Ozone Mapping Spectrometer-Earth Probe) spacecraft bus heritage designed and built by TRW, U.S.A.KOMPSAT-1 program was international co-development program between KARI and TRW funded by Korean Government. be launched in 2004. Main mission objective is to provide geo-information products based on the multi-spectral high resolution sensor called Multi-Spectral Camera (MSC) which will provide 1m panchromatic and 4m multi-spectral high resolution images. ELOP of Israel is the prime contractor of the MSC payload system and KARI is the total system prime contractor including spacecraft bus development and ground segment. KARI also has the contract with Astrium of Europe for the purpose of technical consultation and hardware procurement. Based on the experience throughout KOMPSAT-1 and KOMPSAT-2 space system development, Korea is expecting to establish the infrastructure of developing satellite system. Currently, KOMPSAT-2 program is in the critical design stage. are scheduled to launch in 2008 and in 2014, respectively. The mission of CBMS consists of two areas. One is of space technology test for the communications mission, and the other is of a real

Turbulent convection in liquid metal with and without rotation

PubMed Central

King, Eric M.; Aurnou, Jonathan M.

2013-01-01

The magnetic fields of Earth and other planets are generated by turbulent, rotating convection in liquid metal. Liquid metals are peculiar in that they diffuse heat more readily than momentum, quantified by their small Prandtl numbers, . Most analog models of planetary dynamos, however, use moderate fluids, and the systematic influence of reducing is not well understood. We perform rotating Rayleigh–Bénard convection experiments in the liquid metal gallium over a range of nondimensional buoyancy forcing and rotation periods (E). Our primary diagnostic is the efficiency of convective heat transfer . In general, we find that the convective behavior of liquid metal differs substantially from that of moderate fluids, such as water. In particular, a transition between rotationally constrained and weakly rotating turbulent states is identified, and this transition differs substantially from that observed in moderate fluids. This difference, we hypothesize, may explain the different classes of magnetic fields observed on the Gas and Ice Giant planets, whose dynamo regions consist of and fluids, respectively. PMID:23569262

Automating the Processing of Earth Observation Data

NASA Technical Reports Server (NTRS)

Golden, Keith; Pang, Wan-Lin; Nemani, Ramakrishna; Votava, Petr

2003-01-01

NASA s vision for Earth science is to build a "sensor web": an adaptive array of heterogeneous satellites and other sensors that will track important events, such as storms, and provide real-time information about the state of the Earth to a wide variety of customers. Achieving this vision will require automation not only in the scheduling of the observations but also in the processing of the resulting data. To address this need, we are developing a planner-based agent to automatically generate and execute data-flow programs to produce the requested data products.

The Earth Observing System Terra Mission

NASA Technical Reports Server (NTRS)

Kaufman, Yoram J.; Einaudi, Franco (Technical Monitor)

2000-01-01

Langley's remarkable solar and lunar spectra collected from Mt. Whitney inspired Arrhenius to develop the first quantitative climate model in 1896. After the launch in Dec. 16 1999, NASA's Earth Observing AM Satellite (EOS-Terra) will repeat Langley's experiment, but for the entire planet, thus pioneering a wide array of calibrated spectral observations from space of the Earth System. Conceived in response to real environmental problems, EOS-Terra, in conjunction with other international satellite efforts, will fill a major gap in current efforts by providing quantitative global data sets with a resolution better than 1 km on the physical, chemical and biological elements of the earth system. Thus, like Langley's data, EOS-Terra can revolutionize climate research by inspiring a new generation of climate system models and enable us to assess the human impact on the environment. In the talk I shall review the historical perspective of the Terra mission and the key new elements of the mission. We expect to have first images that demonstrate the most innovative capability from EOS Terra 5 instruments: MODIS - 1.37 micron cirrus cloud channel; 250m daily coverage for clouds and vegetation change; 7 solar channels for land and aerosol studies; new fire channels; Chlorophyll fluorescence; MISR - first 9 multi angle views of clouds and vegetation; MOPITT - first global CO maps and C114 maps; ASTER - Thermal channels for geological studies with 15-90 m resolution.

Benchmark Comparison of Cloud Analytics Methods Applied to Earth Observations

NASA Technical Reports Server (NTRS)

Lynnes, Chris; Little, Mike; Huang, Thomas; Jacob, Joseph; Yang, Phil; Kuo, Kwo-Sen

2016-01-01

Cloud computing has the potential to bring high performance computing capabilities to the average science researcher. However, in order to take full advantage of cloud capabilities, the science data used in the analysis must often be reorganized. This typically involves sharding the data across multiple nodes to enable relatively fine-grained parallelism. This can be either via cloud-based file systems or cloud-enabled databases such as Cassandra, Rasdaman or SciDB. Since storing an extra copy of data leads to increased cost and data management complexity, NASA is interested in determining the benefits and costs of various cloud analytics methods for real Earth Observation cases. Accordingly, NASA's Earth Science Technology Office and Earth Science Data and Information Systems project have teamed with cloud analytics practitioners to run a benchmark comparison on cloud analytics methods using the same input data and analysis algorithms. We have particularly looked at analysis algorithms that work over long time series, because these are particularly intractable for many Earth Observation datasets which typically store data with one or just a few time steps per file. This post will present side-by-side cost and performance results for several common Earth observation analysis operations.

A review of earth observation using mobile personal communication devices

NASA Astrophysics Data System (ADS)

Ferster, Colin J.; Coops, Nicholas C.

2013-02-01

Earth observation using mobile personal communication devices (MPCDs) is a recent advance with considerable promise for acquiring important and timely measurements. Globally, over 5 billion people have access to mobile phones, with an increasing proportion having access to smartphones with capabilities such as a camera, microphone, global positioning system (GPS), data storage, and networked data transfer. Scientists can view these devices as embedded sensors with the potential to take measurements of the Earth's surface and processes. To advance the state of Earth observation using MPCDs, scientists need to consider terms and concepts, from a broad range of disciplines including citizen science, image analysis, and computer vision. In this paper, as a result of our literature review, we identify a number of considerations for Earth observation using MPCDs such as methods of field collection, collecting measurements over broad areas, errors and biases, data processing, and accessibility of data. Developing effective frameworks for mobile data collection with public participation and strategies for minimizing bias, in combination with advancements in image processing techniques, will offer opportunities to collect Earth sensing data across a range of scales and perspectives, complimenting airborne and spaceborne remote sensing measurements.

Benchmark Comparison of Cloud Analytics Methods Applied to Earth Observations

NASA Astrophysics Data System (ADS)

Lynnes, C.; Little, M. M.; Huang, T.; Jacob, J. C.; Yang, C. P.; Kuo, K. S.

2016-12-01

Cloud computing has the potential to bring high performance computing capabilities to the average science researcher. However, in order to take full advantage of cloud capabilities, the science data used in the analysis must often be reorganized. This typically involves sharding the data across multiple nodes to enable relatively fine-grained parallelism. This can be either via cloud-based filesystems or cloud-enabled databases such as Cassandra, Rasdaman or SciDB. Since storing an extra copy of data leads to increased cost and data management complexity, NASA is interested in determining the benefits and costs of various cloud analytics methods for real Earth Observation cases. Accordingly, NASA's Earth Science Technology Office and Earth Science Data and Information Systems project have teamed with cloud analytics practitioners to run a benchmark comparison on cloud analytics methods using the same input data and analysis algorithms. We have particularly looked at analysis algorithms that work over long time series, because these are particularly intractable for many Earth Observation datasets which typically store data with one or just a few time steps per file. This post will present side-by-side cost and performance results for several common Earth observation analysis operations.

Numerical Simulations of Lightcurves of Non-principal Axis Rotators

NASA Astrophysics Data System (ADS)

Mueller, Beatrice E. A.; Samarasinha, N. H.

2012-10-01

Theory predicts that most short-period comets should be in non-principal axis (NPA) rotational states (Jewitt 1997) due to torques caused by outgassing from the nuclei. However the fraction that is currently observed to be in such a state is small (less than 15%; Samarasinha et al 2004, and references therein). This suggests that NPA states naturally occurring as a consequence of cometary jetting are more rapidly damped because comets are structurally far weaker than has been assumed. However, there is a serious question whether this discrepancy is real or an artifact of interpreting lightcurve observations. We will present initial results of our numerical simulation of the observational manifestation of lightcurves over the range of possible NPA rotation states and determine the effects of observing geometry, signal-to-noise, and sampling. References: Jewitt, D. 1997. Cometary Rotation: An Overview. Earth, Moon, and Planets 79, 35-53. Samarasinha, N.H., B.E.A. Mueller, M.J.S. Belton,L. Jorda 2004. Rotation of Cometary Nuclei. In Comets II, pp. 281-299.

Patterns in Crew-Initiated Photography of Earth from ISS - Is Earth Observation a Salutogenic Experience?

NASA Technical Reports Server (NTRS)

Robinson, Julie A.; Slack, Kelley J.; Olson, Valerie A.; Trenchard, Mike; Willis, Kim; Baskin, Pam; Ritsher, Jennifer Boyd

2006-01-01

To provide for the well-being of crewmembers on future exploration missions, understanding how space station crewmembers handle the inherently stressful isolation and confinement during long-duration missions is important. A recent retrospective survey of previously flown astronauts found that the most commonly reported psychologically enriching aspects of spaceflight had to do with their Perceptions of Earth. Crewmembers onboard the International Space Station (ISS) photograph Earth through the station windows. Some of these photographs are in response to requests from scientists on the ground through the Crew Earth Observations (CEO) payload. Other photographs taken by crewmembers have not been in response to these formal requests. The automatically recorded data from the camera provides a dataset that can be used to test hypotheses about factors correlated with self-initiated crewmember photography. The present study used objective in-flight data to corroborate the previous questionnaire finding and to further investigate the nature of voluntary Earth-Observation activity. We examined the distribution of photographs with respect to time, crew, and subject matter. We also determined whether the frequency fluctuated in conjunction with major mission events such as vehicle dockings, and extra-vehicular activities (EVAs, or spacewalks), relative to the norm for the relevant crew. We also examined the influence of geographic and temporal patterns on frequency of Earth photography activities. We tested the hypotheses that there would be peak photography intensity over locations of personal interest, and on weekends. From December 2001 through October 2005 (Expeditions 4-11) crewmembers took 144,180 photographs of Earth with time and date automatically recorded by the camera. Of the time-stamped photographs, 84.5% were crew-initiated, and not in response to CEO requests. Preliminary analysis indicated some phasing in patterns of photography during the course of a

Precession, Nutation and Wobble of the Earth

NASA Astrophysics Data System (ADS)

Dehant, V.; Mathews, P. M.

2015-04-01

Covering both astronomical and geophysical perspectives, this book describes changes in the Earth's orientation, specifically precession and nutation, and how they are observed and computed in terms of tidal forcing and models of the Earth's interior. Following an introduction to key concepts and elementary geodetic theory, the book describes how precise measurements of the Earth's orientation are made using observations of extra-galactic radio-sources by Very Long Baseline Interferometry techniques. It demonstrates how models are used to accurately pinpoint the location and orientation of the Earth with reference to the stars and how to determine variations in its rotation speed. A theoretical framework is also presented that describes the role played by the structure and properties of the Earth's deep interior. Incorporating suggestions for future developments in nutation theory for the next generation models, this book is ideal for advanced-level students and researche! rs in solid Earth geophysics, planetary science and astronomy.

"New Space Explosion" and Earth Observing System Capabilities

NASA Astrophysics Data System (ADS)

Stensaas, G. L.; Casey, K.; Snyder, G. I.; Christopherson, J.

2017-12-01

This presentation will describe recent developments in spaceborne remote sensing, including introduction to some of the increasing number of new firms entering the market, along with new systems and successes from established players, as well as industry consolidation reactions to these developments from communities of users. The information in this presentation will include inputs from the results of the Joint Agency Commercial Imagery Evaluation (JACIE) 2017 Civil Commercial Imagery Evaluation Workshop and the use of the US Geological Survey's Requirements Capabilities and Analysis for Earth Observation (RCA-EO) centralized Earth observing systems database and how system performance parameters are used with user science applications requirements.

Observation of plasma rotation driven by static nonaxisymmetric magnetic fields in a tokamak.

PubMed

Garofalo, A M; Burrell, K H; DeBoo, J C; deGrassie, J S; Jackson, G L; Lanctot, M; Reimerdes, H; Schaffer, M J; Solomon, W M; Strait, E J

2008-11-07

We present the first evidence for the existence of a neoclassical toroidal rotation driven in a direction counter to the plasma current by nonaxisymmetric, nonresonant magnetic fields. At high beta and with large injected neutral beam momentum, the nonresonant field torque slows down the plasma toward the neoclassical "offset" rotation rate. With small injected neutral beam momentum, the toroidal rotation is accelerated toward the offset rotation, with resulting improvement in the global energy confinement time. The observed magnitude, direction, and radial profile of the offset rotation are consistent with neoclassical theory predictions.

Orbital, Rotational, and Climatic Interactions

NASA Technical Reports Server (NTRS)

Bills, Bruce G. (Editor)

1992-01-01

The report of an international meeting on the topic of Orbital, Rotational, and Climatic Interactions, which was held 9-11 Jul. 1991 at the Johns Hopkins University is presented. The meeting was attended by 22 researchers working on various aspects of orbital and rotational dynamics, paleoclimate data analysis and modeling, solid-Earth deformation studies, and paleomagnetic analyses. The primary objective of the workshop was to arrive at a better understanding of the interactions between the orbital, rotational, and climatic variations of the Earth. This report contains a brief introduction and 14 contributed papers which cover most of the topics discussed at the meeting.

Interleaved Observation Execution and Rescheduling on Earth Observing Systems

NASA Technical Reports Server (NTRS)

Khatib, Lina; Frank, Jeremy; Smith, David; Morris, Robert; Dungan, Jennifer

2003-01-01

Observation scheduling for Earth orbiting satellites solves the following problem: given a set of requests for images of the Earth, a set of instruments for acquiring those images distributed on a collecting of orbiting satellites, and a set of temporal and resource constraints, generate a set of assignments of instruments and viewing times to those requests that satisfy those constraints. Observation scheduling is often construed as a constrained optimization problem with the objective of maximizing the overall utility of the science data acquired. The utility of an image is typically based on the intrinsic importance of acquiring it (for example, its importance in meeting a mission or science campaign objective) as well as the expected value of the data given current viewing conditions (for example, if the image is occluded by clouds, its value is usually diminished). Currently, science observation scheduling for Earth Observing Systems is done on the ground, for periods covering a day or more. Schedules are uplinked to the satellites and are executed rigorously. An alternative to this scenario is to do some of the decision-making about what images are to be acquired on-board. The principal argument for this capability is that the desirability of making an observation can change dynamically, because of changes in meteorological conditions (e.g. cloud cover), unforeseen events such as fires, floods, or volcanic eruptions, or un-expected changes in satellite or ground station capability. Furthermore, since satellites can only communicate with the ground between 5% to 10% of the time, it may be infeasible to make the desired changes to the schedule on the ground, and uplink the revisions in time for the on-board system to execute them. Examples of scenarios that motivate an on-board capability for revising schedules include the following. First, if a desired visual scene is completely obscured by clouds, then there is little point in taking it. In this case

BingEO: Enable Distributed Earth Observation Data for Environmental Research

NASA Astrophysics Data System (ADS)

Wu, H.; Yang, C.; Xu, Y.

2010-12-01

Our planet is facing great environmental challenges including global climate change, environmental vulnerability, extreme poverty, and a shortage of clean cheap energy. To address these problems, scientists are developing various models to analysis, forecast, simulate various geospatial phenomena to support critical decision making. These models not only challenge our computing technology, but also challenge us to feed huge demands of earth observation data. Through various policies and programs, open and free sharing of earth observation data are advocated in earth science. Currently, thousands of data sources are freely available online through open standards such as Web Map Service (WMS), Web Feature Service (WFS) and Web Coverage Service (WCS). Seamless sharing and access to these resources call for a spatial Cyberinfrastructure (CI) to enable the use of spatial data for the advancement of related applied sciences including environmental research. Based on Microsoft Bing Search Engine and Bing Map, a seamlessly integrated and visual tool is under development to bridge the gap between researchers/educators and earth observation data providers. With this tool, earth science researchers/educators can easily and visually find the best data sets for their research and education. The tool includes a registry and its related supporting module at server-side and an integrated portal as its client. The proposed portal, Bing Earth Observation (BingEO), is based on Bing Search and Bing Map to: 1) Use Bing Search to discover Web Map Services (WMS) resources available over the internet; 2) Develop and maintain a registry to manage all the available WMS resources and constantly monitor their service quality; 3) Allow users to manually register data services; 4) Provide a Bing Maps-based Web application to visualize the data on a high-quality and easy-to-manipulate map platform and enable users to select the best data layers online. Given the amount of observation data

Aspiring to Spectral Ignorance in Earth Observation

NASA Astrophysics Data System (ADS)

Oliver, S. A.

2016-12-01

Enabling robust, defensible and integrated decision making in the Era of Big Earth Data requires the fusion of data from multiple and diverse sensor platforms and networks. While the application of standardised global grid systems provides a common spatial analytics framework that facilitates the computationally efficient and statistically valid integration and analysis of these various data sources across multiple scales, there remains the challenge of sensor equivalency; particularly when combining data from different earth observation satellite sensors (e.g. combining Landsat and Sentinel-2 observations). To realise the vision of a sensor ignorant analytics platform for earth observation we require automation of spectral matching across the available sensors. Ultimately, the aim is to remove the requirement for the user to possess any sensor knowledge in order to undertake analysis. This paper introduces the concept of spectral equivalence and proposes a methodology through which equivalent bands may be sourced from a set of potential target sensors through application of equivalence metrics and thresholds. A number of parameters can be used to determine whether a pair of spectra are equivalent for the purposes of analysis. A baseline set of thresholds for these parameters and how to apply them systematically to enable relation of spectral bands amongst numerous different sensors is proposed. The base unit for comparison in this work is the relative spectral response. From this input, determination of a what may constitute equivalence can be related by a user, based on their own conceptualisation of equivalence.

Application of precise altimetry to the study of precise leveling of the sea surface, the Earth's gravity field, and the rotation of the Earth

NASA Technical Reports Server (NTRS)

Segawa, J.; Ganeko, Y.; Sasaki, M.; Mori, T.; Ooe, M.; Nakagawa, I.; Ishii, H.; Hagiwara, Y.

1991-01-01

Our program includes five research items: (1) determination of a precision geoid and gravity anomaly field; (2) precise leveling and detection of tidal changes of the sea surface and study of the role of the tide in the global energy exchange; (3) oceanic effect on the Earth's rotation and polar motion; (4) geological and geophysical interpretation of the altimetry gravity field; and (5) evaluation of the effectiveness of local tracking of TOPEX/POSEIDON by use of a laser tracker.

Observing rotation and deformation of sea ice with synthetic aperture radar

NASA Technical Reports Server (NTRS)

Vesecky, J. F.; Samadani, R.; Daida, J. M.; Smith, M. P.; Bracewell, R. N.

1987-01-01

The ESA's ERS-1 satellite will carry SARs over the polar regions; an important component in the use of these data is an automated scheme for the extraction of sea ice velocity fields from a sequence of SAR images of the same geographical region. The image pyramid area-correlation hierarchical method is noted to be vulnerable to uncertainties for sea ice rotations greater than 10-15 deg between SAR observations. Rotation-invariant methods can successfully track isolated floes in the marginal ice zone. Hu's (1962) invariant moments are also worth considering as a possible basis for rotation-invariant tracking methods. Feature tracking is inherently robust for tracking rotating sea ice, but is limited when features are floe-lead boundaries. A variety of techniques appears neccessary.

Observations of Intrinsic Rotation Reversal Hysteresis in Alcator C-Mod Plasmas

NASA Astrophysics Data System (ADS)

Cao, Norman; Rice, John; White, Anne; Baek, Seung; Chilenski, Mark; Creely, Alexander; Ennever, Paul; Hubbard, Amanda; Hughes, Jerry; Irby, Jim; Rodriguez-Fernandez, Pablo; Reinke, Matthew; Diamond, Patrick; Alcator C-Mod Team

2016-10-01

Intrinsic core toroidal rotation in Alcator C-Mod L-mode plasmas has been observed to spontaneously reverse direction when the normalized collisionality ν*, evaluated at the profile minimum, passes through a critical value around 0.4. In Ohmic plasmas, the low density linear Ohmic confinement regime exhibits co-current toroidal rotation, and the higher density saturated Ohmic confinement regime exhibits counter-current rotation. The reversal manifests a hysteresis loop in ν*, where the critical collisionalities for the forward and reverse transitions differ by 10-15%. There appears to be memory associated with the rotation state, since reversals which do not begin from fully saturated rotation states do not manifest this hysteresis. In addition, high-k PCI fluctuation ``wings'' (kθρs up to 1) at low density and high current appear only in the co-current rotation state, while density peaking and ``non-local'' heat transport behavior do not appear to change significantly with the rotation state. Results from fluctuation measurements and preliminary transport and stability analyses will also be presented. This work is supported by the US DOE under Grant DE-FC02-99ER54512 (C-Mod).

Earth Observing Scanning Polarimeter (EOSP), phase B

NASA Technical Reports Server (NTRS)

1990-01-01

Evaluations performed during a Phase B study directed towards defining an optimal design for the Earth Observing Scanning Polarimeter (EOSP) instrument is summarized. An overview of the experiment approach is included which provides a summary of the scientific objectives, the background of the measurement approach, and the measurement method. In the instrumentation section, details of the design are discussed starting with the key instrument features required to accomplish the scientific objectives and a system characterization in terms of the Stokes vector/Mueller matrix formalism. This is followed by a detailing of the instrument design concept, the design of the individual elements of the system, the predicted performance, and a summary of appropriate instrument testing and calibration. The selected design makes use of key features of predecessor polarimeters and is fully compatible with the Earth Observing System spacecraft requirements.

Earth Observation from Space: Competition or Cooperation?

DTIC Science & Technology

1992-04-01

or remote sensing from space (2). Earth observations or remote sensing includes all forms of observation by sensors borne by a space object including...3). The capabilities of remote sensing are as varied as the sensors that are built and put in orbit, but =- • I •1 capabilities fall into two...adversary or ally. For example, the ability of one nation to observe and study another through space-borne sensors permits strategic assessment of a

Earth Observation

NASA Image and Video Library

2014-06-07

ISS040-E-008174 (7 June 2014) --- Layers of Earth's atmosphere, brightly colored as the sun rises, are featured in this image photographed by an Expedition 40 crew member on the International Space Station.

Earth observations from space: History, promise, and reality. Executive summary

NASA Technical Reports Server (NTRS)

1995-01-01

In this report the Committee on Earth Studies (CES), a standing committee of the Space Studies Board (SSB) within the National Research Council (NRC), reviews the recent history (nominally from 1981 to 1995) of the U.S. earth observations programs that serve civilian needs. The principal observations programs examined are those of NASA and the National Oceanic and Atmospheric Administration (NOAA). The Air Force' s Defense Meteorological Satellite Program (DMSP) is discussed, but only from the perspective of its relationship to civil needs and the planned merger with the NOAA polar-orbiting system. The report also reviews the interfaces between the earth observations satellite programs and the major national and international environmental monitoring and research programs. The monitoring and research programs discussed are the U.S. Global Change Research Program (USGCRP), the International Geosphere-Biosphere Program (IGBP), the World Climate Research Program (WCRP), related international scientific campaigns, and operational programs for the sharing and application of environmental data. The purpose of this report is to provide a broad historical review and commentary based on the views of the CES members, with particular emphasis on tracing the lengthy record of advisory committee recommendations. Any individual topic could be the subject of an extended report in its own right. Indeed, extensive further reviews are already under way to that end. If the CES has succeeded in the task it has undertaken. This report will serve as a useful starting point for any such more intensive study. The report is divided into eight chapters: ( I ) an introduction, (2) the evolution of the MTPE, (3) its relationship to the USGCRP, (4) applications of earth observations data, (5) the role that smaller satellites can play in research and operational remote sensing, (6) earth system modeling and information systems, (7) a number of associated activities that contribute to the MTPE

STS-45 Earth observation of the Aurora Australis or Southern Lights

NASA Image and Video Library

1992-04-02

STS-45 Earth observation taken onboard Atlantis, Orbiter Vehicle (OV) 104, is of the Aurora Australis or Southern Lights. The green appearing auroral activity engulfs the thin blue line on the Earth's limb. Aurorae were observed and photographed throughout the STS-45 nine-day mission.

STS-45 Earth observation of the Aurora Australis or Southern Lights

NASA Technical Reports Server (NTRS)

1992-01-01

STS-45 Earth observation taken onboard Atlantis, Orbiter Vehicle (OV) 104, is of the Aurora Australis or Southern Lights. The green appearing auroral activity engulfs the thin blue line on the Earth's limb. Aurorae were observed and photographed throughout the STS-45 nine-day mission.

Global Partnership in Global Earth Observations

NASA Astrophysics Data System (ADS)

Smirnov, A.; Obersteiner, M.

2007-12-01

The emergence of a global partnership on earth observations will crucially drive the configuration of future observing systems and consequently shape how socio-economic benefits are generated. In this paper we take a game-theoretical approach to model cooperation on building global earth observation systems. We consider several societies whose economies are subject to shocks mimicking major natural disasters. Economies operate optimally and lead to the best possible expected value for the social welfares in the future. In order to increase its welfare even more society can make a decision to invest into a global alerting system which lowers the risk of disasters. We start our investigation from a single-society case and show conditions under which benefits of such investment can be reaped. The propensity to invest increases with economic affluence and degree of vulnerability to natural disasters. We find that for poor and/or less vulnerable countries it is better to forbear from investment. If to consider a situation of multiple societies a strategic gaming situation emerges motivated by the fact that every society will benefit from a global system regardless of whether they invested or not. Our analysis of possible equilibrium solutions shows that similar to the formation of trading blocks (e.g. EU, NAFTA) only in the case of similar societies we will observe cooperation behavior (when all invest) and otherwise we will observe free-riding. This insight, that we might face a prisoners dilemma problem in the formation of a GEOSS, has important implications for the GEO process.

Spanish Earth Observation Satellite System

NASA Astrophysics Data System (ADS)

Borges, A.; Cerezo, F.; Fernandez, M.; Lomba, J.; Lopez, M.; Moreno, J.; Neira, A.; Quintana, C.; Torres, J.; Trigo, R.; Urena, J.; Vega, E.; Vez, E.

2010-12-01

The Spanish Ministry of Industry, Tourism and Trade (MITyC) and the Ministry of Defense (MoD) signed an agreement in 2007 for the development of a "Spanish Earth Observation Satellite System" based, in first instance, on two satellites: a high resolution optical satellite, called SEOSAT/Ingenio, and a radar satellite based on SAR technology, called SEOSAR/Paz. SEOSAT/Ingenio is managed by MITyC through the Centre for the Development of Industrial Technology (CDTI), with technical and contractual support from the European Space Agency (ESA). HISDESA T together with the Spanish Instituto Nacional de Técnica Aeroespacial (INTA, National Institute for Aerospace Technology) will be responsible for the in-orbit operation and the commercial operation of both satellites, and for the technical management of SEOSAR/Paz on behalf of the MoD. In both cases EADS CASA Espacio (ECE) is the prime contractor leading the industrial consortia. The ground segment development will be assigned to a Spanish consortium. This system is the most important contribution of Spain to the European Programme Global Monitoring for Environment and Security, GMES. This paper presents the Spanish Earth Observation Satellite System focusing on SEOSA T/Ingenio Programme and with special emphasis in the potential contribution to the ESA Third Party Missions Programme and to the Global Monitoring for Environment and Security initiative (GMES) Data Access.

The Earth Phenomena Observing System: Intelligent Autonomy for Satellite Operations

NASA Technical Reports Server (NTRS)

Ricard, Michael; Abramson, Mark; Carter, David; Kolitz, Stephan

2003-01-01

Earth monitoring systems of the future may include large numbers of inexpensive small satellites, tasked in a coordinated fashion to observe both long term and transient targets. For best performance, a tool which helps operators optimally assign targets to satellites will be required. We present the design of algorithms developed for real-time optimized autonomous planning of large numbers of small single-sensor Earth observation satellites. The algorithms will reduce requirements on the human operators of such a system of satellites, ensure good utilization of system resources, and provide the capability to dynamically respond to temporal terrestrial phenomena. Our initial real-time system model consists of approximately 100 satellites and large number of points of interest on Earth (e.g., hurricanes, volcanoes, and forest fires) with the objective to maximize the total science value of observations over time. Several options for calculating the science value of observations include the following: 1) total observation time, 2) number of observations, and the 3) quality (a function of e.g., sensor type, range, slant angle) of the observations. An integrated approach using integer programming, optimization and astrodynamics is used to calculate optimized observation and sensor tasking plans.

Earth Observation

NASA Image and Video Library

2014-06-02

ISS040-E-006817 (2 June 2014) --- Intersecting the thin line of Earth's atmosphere, International Space Station solar array wings are featured in this image photographed by an Expedition 40 crew member on the International Space Station.

Gravitational Core-Mantle Coupling and the Acceleration of the Earth

NASA Technical Reports Server (NTRS)

Rubincam, David Parry; Smith, David E. (Technical Monitor)

2001-01-01

Gravitational core-mantle coupling may be the cause of the observed variable acceleration of the Earth's rotation on the 1000 year timescale. The idea is that density inhomogeneities which randomly come and go in the liquid outer core gravitationally attract density inhomogeneities in the mantle and crust, torquing the mantle and changing its rotation state. The corresponding torque by the mantle on the core may also explain the westward drift of the magnetic field of 0.2 deg per year. Gravitational core-mantle coupling would stochastically affect the rate of change of the Earth's obliquity by just a few per cent. Its contribution to polar wander would only be about 0.5% the presently observed rate. Tidal friction is slowing down the rotation of the Earth, overwhelming a smaller positive acceleration from postglacial rebound. Coupling between the liquid outer core of the Earth and the mantle has long been a suspected reason for changes in the length-of-day. The present investigation focuses on the gravitational coupling between the density anomalies in the convecting liquid outer core and those in the mantle and crust as a possible cause for the observed nonsecular acceleration on the millenial timescale. The basic idea is as follows. There are density inhomogeneities caused by blobs circulating in the outer core like the blobs in a lava lamp; thus the outer core's gravitational field is not featureless. Moreover, these blobs will form and dissipate somewhat randomly. Thus there will be a time variability to the fields. These density inhomogeneities will gravitationally attract the density anomalies in the mantle.

Planning for the Global Earth Observation System of Systems (GEOSS)

USGS Publications Warehouse

Christian, E.

2005-01-01

The Group on Earth Observations was established to promote comprehensive, coordinated, and sustained Earth observations. Its mandate is to implement the Global Earth Observation System of Systems (GEOSS) in accord with the GEOSS 10-Year Implementation Plan and Reference Document. During the months over which the GEOSS Implementation Plan was developed, many issues surfaced and were addressed. This article discusses several of the more interesting or challenging of those issues-e.g. fitting in with existing organizations and securing stable funding - some of which have yet to be resolved fully as of this writing. Despite the relatively short period over which the Implementation Plan had to be developed, there is a good chance that the work undertaken will be influential for decades to come. ?? 2005 Elsevier Ltd. All rights reserved.

Geodetic Earth Observation

NASA Astrophysics Data System (ADS)

Rothacher, Markus

2017-04-01

Mankind is constantly threatened by a variety of natural disasters and global change phenomena. In order to be able to better predict and assess these catastrophic and disastrous events a continuous observation and monitoring of the causative Earth processes is a necessity. These processes may happen in time scales from extremely short (earthquakes, volcano eruptions, land slides, ...) to very long (melting of ice sheets, sea level change, plate tectonics, ...). Appropriate monitoring and early warning systems must allow, therefore, the detection and quantification of catastrophic events in (near) real-time on the one hand and the reliable identification of barely noticeable, but crucial long-term trends (e.g., sea level rise) on the other hand. The Global Geodetic Observing System (GGOS), established by the International Association of Geodesy (IAG) in 2003, already now contributes in a multitude of ways to meet this challenge, e.g., by providing a highly accurate and stable global reference frame, without which the measurement of a sea level rise of 2-3 mm/y would not be possible; by measuring displacements in near real-time and deformations over decades that offer valuable clues to plate tectonics, earthquake processes, tsunamis, volcanos, land slides, and glaciers dynamics; by observing the mass loss of ice sheets with gravity satellite missions; and by estimating essential variables such as the amount of water vapor in the troposphere relevant for weather predictions and climate and the content of free electrons in the ionosphere crucial for space weather.

Defunct Satellites, Rotation Rates and the YORP Effect

NASA Astrophysics Data System (ADS)

Albuja, A.; Scheeres, D.

2013-09-01

With the increasing number of defunct satellites and associated space debris found in orbit, it is important to understand the dynamics governing the motion of these bodies. Orbit perturbations are coupled with the body's attitude dynamics; therefore it is necessary to have an understanding of attitude dynamics for accurate predictions of debris orbits. Additionally, it is important to have a clear idea of the rotational dynamics of such objects for removal and mitigation purposes. The Yarkovsky-O'Keefe-Raszvieskii-Paddack (YORP) effect has been well studied and credited for the observed secular change in angular velocity of various asteroids. The YORP effect arises due to sunlight being either absorbed and re-emitted as energy or being directly reflected, creating a net downward force on the body's surface. As a result of both of these factors, an overall torque is created on the body yielding a change in the rotational dynamics. While YORP has been extensively studied for asteroids, it has yet to be systematically applied to objects in Earth orbit such as space debris. This paper analyzes the effects of YORP on the obliquity and angular velocity of defunct satellites and other pieces of debris found in Earth orbit. The rotational dynamics are first averaged over the rotational period and next over the orbital period of the Earth, about which the debris is assumed to be orbiting. Using these averaged dynamics, long-term predictions of the evolution of both angular velocity and obliquity are made. In the analysis simulation results are compared to published observational data for defunct satellites. The observed rotation periods of the satellites are used to compute how much torque would be required to obtain such a period only due to YORP. These required torques are compared to the torques that we predict to be acting on these satellites. As an example of what we will present, consider the GEO satellite Gorizont-11. The normalized inferred coefficient for the

CEOS Committee on Earth Observations Satellites Consolidated Report, 1992

NASA Technical Reports Server (NTRS)

1992-01-01

A concise overview of the committee on Earth Observations Satellites (CEOS) and its Working Groups, covering the history and purpose of the Committee and its accomplishments to date are provided. The report will be updated annually before each Plenary meeting, and as developments in the Working Groups warrant. The committee on Earth Observations Satellites (originally named the International Earth Observations Satellite committee, IEOS) was treated in 1984, in response to a recommendation from the Economic Summit of Industrialized Nations Working Group on Growth, Technology, and Employment's Panel of Experts on Satellite Remote Sensing. This group recognized the multidisciplinary nature of satellite Earth observations, and the value of coordinating across all proposed missions. Thus, CEOS combined the previously existing groups for coordination on Ocean Remote-Sensing Satellites (CORSS) and coordination on Land Remote-Sensing Satellites (CLRSS), and established a broad framework for coordination across all spaceborne Earth observations missions. The first three LEOS Plenary meetings focused on treating and guiding the Working Groups deemed necessary to carry out the objectives of the CEOS members. After the third meeting, it was agreed that a more active orientation was required by the Plenary, and additional issues were brought before the group at the fourth meeting. At the fifth Plenary, international scientific programs and relevant intergovernmental organizations accepted invitations and participated as affiliate members of CEOS. This enabled progress toward integrating satellite data users' requirements into the CEOS process. Data exchange principles for global change research were also adopted. An interim CEOS Plenary meeting was held in April 1992, in preparation for the United Nations Conference on Environment and Development (UNCED). Brief encapsulations of the Plenary sessions immediately follow the Terms of Reference that govern the activities of CEOS as

Earth Observation

NASA Image and Video Library

2013-05-19

ISS036-E-002224 (21 May 2013) --- The sun is captured in a "starburst" mode over Earth's horizon by one of the Expedition 36 crew members as the orbital outpost was above a point in southwestern Minnesota on May 21, 2013.

On the tidal effects in the motion of earth satellites and the love parameters of the earth

NASA Technical Reports Server (NTRS)

Musen, P.; Estes, R.

1972-01-01

The tidal effects in the motion of artificial satellites are studied to determine the elastic properties of the earth as they are observed from extraterrestrial space. Considering Love numbers, the disturbing potential is obtained as the analytical continuation of the tidal potential from the surface of the earth into-outer space, with parameters which characterize the earth's elastic response to tidal attraction by the moon and the sun. It is concluded that the tidal effects represent a superposition of a large number of periodic terms, and the rotation of the lunar orbital plane produces a term of 18 years period in tidal perturbations of the ascending node of the satellite's orbit.

Fortnightly Ocean Tides, Earth Rotation, and Mantle Anelasticity

NASA Technical Reports Server (NTRS)

Ray, Richard; Egbert, Gary

2012-01-01

The fortnightly Mf ocean tide is the largest of the long-period tides (periods between 1 week and 18.6 years), but Mf is still very small, generally 2 cm or less. All long-period tides are thought to be near equilibrium with the astronomical tidal potential, with an almost pure zonal structure. However, several lines of evidence point to Mf having a significant dynamic response to forcing. We use a combination of numerical modeling, satellite altimetry, and observations of polar motion to determine the Mf ocean tide and to place constraints on certain global properties, such as angular momentum. Polar motion provides the only constraints on Mf tidal currents. With a model of the Mf ocean tide in hand, we use it to remove the effects of the ocean from estimates of fortnightly variations in length-of-day. The latter is dominated by the earth's body tide, but a small residual allows us to place new constraints on the anelasticity of the earth's mantle. The result gives the first experimental confirmation of theoretical predictions made by Wahr and Bergen in 1986.

Planning and Scheduling for Fleets of Earth Observing Satellites

NASA Technical Reports Server (NTRS)

Frank, Jeremy; Jonsson, Ari; Morris, Robert; Smith, David E.; Norvig, Peter (Technical Monitor)

2001-01-01

We address the problem of scheduling observations for a collection of earth observing satellites. This scheduling task is a difficult optimization problem, potentially involving many satellites, hundreds of requests, constraints on when and how to service each request, and resources such as instruments, recording devices, transmitters, and ground stations. High-fidelity models are required to ensure the validity of schedules; at the same time, the size and complexity of the problem makes it unlikely that systematic optimization search methods will be able to solve them in a reasonable time. This paper presents a constraint-based approach to solving the Earth Observing Satellites (EOS) scheduling problem, and proposes a stochastic heuristic search method for solving it.

Four dimensional studies in earth space

NASA Technical Reports Server (NTRS)

Mather, R. S.

1972-01-01

A system of reference which is directly related to observations, is proposed for four-dimensional studies in earth space. Global control network and polar wandering are defined. The determination of variations in the earth's gravitational field with time also forms part of such a system. Techniques are outlined for the unique definition of the motion of the geocenter, and the changes in the location of the axis of rotation of an instantaneous earth model, in relation to values at some epoch of reference. The instantaneous system referred to is directly related to a fundamental equation in geodynamics. The reference system defined would provide an unambiguous frame for long period studies in earth space, provided the scale of the space were specified.

Deformations and Rotational Ground Motions Inferred from Downhole Vertical Array Observations

NASA Astrophysics Data System (ADS)

Graizer, V.

2017-12-01

Only few direct reliable measurements of rotational component of strong earthquake ground motions are obtained so far. In the meantime, high quality data recorded at downhole vertical arrays during a number of earthquakes provide an opportunity to calculate deformations based on the differences in ground motions recorded simultaneously at different depths. More than twenty high resolution strong motion downhole vertical arrays were installed in California with primary goal to study site response of different geologic structures to strong motion. Deformation or simple shear strain with the rate γ is the combination of pure shear strain with the rate γ/2 and rotation with the rate of α=γ/2. Deformations and rotations were inferred from downhole array records of the Mw 6.0 Parkfield 2004, the Mw 7.2 Sierra El Mayor (Mexico) 2010, the Mw 6.5 Ferndale area in N. California 2010 and the two smaller earthquakes in California. Highest amplitude of rotation of 0.60E-03 rad was observed at the Eureka array corresponding to ground velocity of 35 cm/s, and highest rotation rate of 0.55E-02 rad/s associated with the S-wave was observed at a close epicentral distance of 4.3 km from the ML 4.2 event in Southern California at the La Cienega array. Large magnitude Sierra El Mayor earthquake produced long duration rotational motions of up to 1.5E-04 rad and 2.05E-03 rad/s associated with shear and surface waves at the El Centro array at closest fault distance of 33.4km. Rotational motions of such levels, especially tilting can have significant effect on structures. High dynamic range well synchronized and properly oriented instrumentation is necessary for reliable calculation of rotations from vertical array data. Data from the dense Treasure Island array near San Francisco demonstrate consistent change of shape of rotational motion with depth and material. In the frequency range of 1-15 Hz Fourier amplitude spectrum of vertical ground velocity is similar to the scaled tilt

Transforming Water Management: an Emerging Promise of Integrated Earth Observations

NASA Astrophysics Data System (ADS)

Lawford, R. G.

2011-12-01

Throughout its history, civilization has relied on technology to facilitate many of its advances. New innovations and technologies have often provided strategic advantages that have led to transformations in institutions, economies and ultimately societies. Observational and information technologies are leading to significant developments in the water sector. After a brief introduction tracing the role of observational technologies in the areas of hydrology and water cycle science, this talk explores the existing and potential contributions of remote sensing data in water resource management around the world. In particular, it outlines the steps being undertaken by the Group on Earth Observations (GEO) and its Water Task to facilitate capacity building efforts in water management using Earth Observations in Asia, Africa and Latin and Caribbean America. Success stories on the benefits of using Earth Observations and applying GEO principles are provided. While GEO and its capacity building efforts are contributing to the transformation of water management through interoperability, data sharing, and capacity building, the full potential of these contributions has not been fully realized because impediments and challenges still remain.

A comprehensive study on rotation reversal in KSTAR: experimental observations and modelling

NASA Astrophysics Data System (ADS)

Na, D. H.; Na, Yong-Su; Angioni, C.; Yang, S. M.; Kwon, J. M.; Jhang, Hogun; Camenen, Y.; Lee, S. G.; Shi, Y. J.; Ko, W. H.; Lee, J. A.; Hahm, T. S.; KSTAR Team

2017-12-01

Dedicated experiments have been performed in KSTAR Ohmic plasmas to investigate the detailed physics of the rotation reversal phenomena. Here we adapt the more general definition of rotation reversal, a large change of the intrinsic toroidal rotation gradient produced by minor changes in the control parameters (Camenen et al 2017 Plasma Phys. Control. Fusion 59 034001), which is commonly observed in KSTAR regardless of the operating conditions. The two main phenomenological features of the rotation reversal are the normalized toroidal rotation gradient ({{u}\\prime} ) change in the gradient region and the existence of an anchor point. For the KSTAR Ohmic plasma database including the experiment results up to the 2016 experimental campaign, both features were investigated. First, the observations show that the locations of the gradient and the anchor point region are dependent on {{q}95} . Second, a strong dependence of {{u}\\prime} on {νeff} is clearly observed in the gradient region, whereas the dependence on R/{{L}{{Ti}}} , R/{{L}{{Te}}} , and R/{{L}{{ne}}} is unclear considering the usual variation of the normalized gradient length in KSTAR. The experimental observations were compared against several theoretical models. The rotation reversal might not occur due to the transition of the dominant turbulence from the trapped electron mode to the ion temperature gradient mode or the neoclassical equilibrium effect in KSTAR. Instead, it seems that the profile shearing effects associated with a finite ballooning tilting well reproduce the experimental observations of both the gradient region and the anchor point; the difference seems to be related to the magnetic shear and the q value. Further analysis implies that the increase of {{u}\\prime} in the gradient region with the increase of the collisionality would occur when the reduction of the momentum diffusivity is comparatively larger than the reduction of the residual stress. It is supported by the perturbative

Enhancing Earth Observation Capacity in the Himalayan Region

NASA Astrophysics Data System (ADS)

Shrestha, B. R.

2012-12-01

Earth observations bear special significance in the Himalayan Region owing to the fact that routine data collections are often hampered by highly inaccessible terrain and harsh climatic conditions. The ongoing rapid environmental changes have further emphasized its relevance and use for informed decision-making. The International Center for Integrated Mountain Development (ICIMOD), with a regional mandate is promoting the use of earth observations in line with the GEOSS societal benefit areas. ICIMOD has a proven track record to utilize earth observations notably in the areas of understanding glaciers and snow dynamics, disaster risk preparedness and emergency response, carbon estimation for community forestry user groups, land cover change assessment, agriculture monitoring and food security analysis among others. This paper presents the challenges and lessons learned as a part of capacity building of ICIMOD to utilize earth observations with the primary objectives to empower its member countries and foster regional cooperation. As a part of capacity building, ICIMOD continues to make its efforts to augment as a regional resource center on earth observation and geospatial applications for sustainable mountain development. Capacity building possesses multitude of challenges in the region: the complex geo-political reality with differentiated capacities of member states, poorer institutional and technical infrastructure; addressing the needs for multiple user and target groups; integration with different thematic disciplines; and high resources intensity and sustainability. A capacity building framework was developed based on detailed needs assessment with a regional approach and strategy to enhance capability of ICIMOD and its network of national partners. A specialized one-week training course and curriculum have been designed for different thematic areas to impart knowledge and skills that include development practitioners, professionals, researchers and

Earth Observations taken by Expedition 34 crewmember

NASA Image and Video Library

2013-02-14

ISS034-E-48455 (14 Feb. 2013) --- Looking out at Earth?s surface from the International Space Station (ISS), astronauts and cosmonauts frequently observe sunglint highlighting both ocean and inland water surfaces. The Atlantic Ocean, including Cape Cod Bay and Buzzards Bay, along the coastlines of Massachusetts and Rhode Island, has a burnished, mirror-like appearance in this image. This is due to sunlight reflected off the water surface back towards the station crew member who took the photo. The peak reflection point is towards the right side of the image, lending the waters of Long Island Sound and the upper Massachusetts coastline an even brighter appearance. Sunglint also illuminates the surface waters of Chesapeake Bay, located over 400 kilometers (250 miles) to the southwest of the tip of Long Island. This suggests that the Sun was low on the horizon due to the observed extent of the sunglint effect. The time of image acquisition, approximately 4:26 p.m. Eastern Standard Time, was about one hour before local sunset. There is little in this image to indicate that the region was still recovering from a major winter storm that dropped almost one meter (three feet) of snow over much of the northeastern USA less than a week earlier. The high viewing angle from the space station also allows Earth?s curvature, or limb, to be seen; blue atmospheric layers gradually fade into the darkness of space across the top part of the image. Low clouds near Cape Cod, Long Island, and further down the Atlantic coastline cast shadows over the water surfaces, reducing the sunglint in some areas.

The Rotation of M Dwarfs Observed by the Apache Point Galactic Evolution Experiment

NASA Astrophysics Data System (ADS)

Gilhool, Steven H.; Blake, Cullen H.; Terrien, Ryan C.; Bender, Chad; Mahadevan, Suvrath; Deshpande, Rohit

2018-01-01

We present the results of a spectroscopic analysis of rotational velocities in 714 M-dwarf stars observed by the SDSS-III Apache Point Galactic Evolution Experiment (APOGEE) survey. We use a template-fitting technique to estimate v\\sin i while simultaneously estimating {log}g, [{{M}}/{{H}}], and {T}{eff}. We conservatively estimate that our detection limit is 8 km s‑1. We compare our results to M-dwarf rotation studies in the literature based on both spectroscopic and photometric measurements. Like other authors, we find an increase in the fraction of rapid rotators with decreasing stellar temperature, exemplified by a sharp increase in rotation near the M4 transition to fully convective stellar interiors, which is consistent with the hypothesis that fully convective stars are unable to shed angular momentum as efficiently as those with radiative cores. We compare a sample of targets observed both by APOGEE and the MEarth transiting planet survey and find no cases where the measured v\\sin i and rotation period are physically inconsistent, requiring \\sin i> 1. We compare our spectroscopic results to the fraction of rotators inferred from photometric surveys and find that while the results are broadly consistent, the photometric surveys exhibit a smaller fraction of rotators beyond the M4 transition by a factor of ∼2. We discuss possible reasons for this discrepancy. Given our detection limit, our results are consistent with a bimodal distribution in rotation that is seen in photometric surveys.

Value of Earth Observations: Key principles and techniques of socioeconomic benefits analysis (Invited)

NASA Astrophysics Data System (ADS)

Friedl, L.; Macauley, M.; Bernknopf, R.

2013-12-01

Internationally, multiple organizations are placing greater emphasis on the societal benefits that governments, businesses, and NGOs can derive from applications of Earth-observing satellite observations, research, and models. A growing set of qualitative, anecdotal examples on the uses of Earth observations across a range of sectors can be complemented by the quantitative substantiation of the socioeconomic benefits. In turn, the expanding breadth of environmental data available and the awareness of their beneficial applications to inform decisions can support new products and services by companies, agencies, and civil society. There are, however, significant efforts needed to bridge the Earth sciences and social and economic sciences fields to build capacity, develop case studies, and refine analytic techniques in quantifying socioeconomic benefits from the use of Earth observations. Some government programs, such as the NASA Earth Science Division's Applied Sciences Program have initiated activities in recent years to quantify the socioeconomic benefits from applications of Earth observations research, and to develop multidisciplinary models for organizations' decision-making activities. A community of practice has conducted workshops, developed impact analysis reports, published a book, developed a primer, and pursued other activities to advance analytic methodologies and build capacity. This paper will present an overview of measuring socioeconomic impacts of Earth observations and how the measures can be translated into a value of Earth observation information. It will address key terms, techniques, principles and applications of socioeconomic impact analyses. It will also discuss activities to pursue a research agenda on analytic techniques, develop a body of knowledge, and promote broader skills and capabilities.

Fireball flickering: the case for indirect measurement of meteoroid rotation rates

NASA Astrophysics Data System (ADS)

Beech, Martin; Brown, Peter

2000-08-01

Data collected during the Meteorite Observation and Recovery Program (MORP) indicate that 4% of bright fireballs show a periodic variation or flickering in brightness. The observed flickering frequencies vary from a few Hz to as high as 500 Hz. We interpret the flickering phenomenon in terms of meteoroid rotation. The MORP data does not reveal any apparent correlation between the flickering frequency and the properties of the meteoroid or the atmospheric flow conditions under which ablation is taking place. It is argued that the most likely cause of the flickering phenomenon is the rotational modulation of the cross-section area presented by the meteoroid to the on-coming airflow. A study is made of the Peekskill fireball and it is concluded that the meteoroid was spun-up during its long flight through the Earth's atmosphere, and that its initial brake up was due to rotational bursting. We also argue that the Peekskill event provides the best observational evidence that the flickering phenomenon is truly related to the rotation rate of the impinging meteoroid. We find that the observed rotation rates of the MORP fireballs are clustered just below the allowed limit set by rotational bursting, but argue that this is due to an observational selection effect that mitigates against the detection of low-frequency flickering.

Earth observing system - Concepts and implementation strategy

NASA Technical Reports Server (NTRS)

Hartle, R. E.

1986-01-01

The concepts of an Earth Observing System (EOS), an information system being developed by the EOS Science and Mission Requirements Working Group for international use and planned to begin in the 1990s, are discussed. The EOS is designed to study the factors that control the earth's hydrologic cycle, biochemical cycles, and climatologic processes by combining the measurements from remote sensing instruments, in situ measurement devices, and a data and information system. Three EOS platforms are planned to be launched into low, polar, sun-synchronous orbits during the Space Station's Initial Operating Configuration, one to be provided by ESA and two by the United States.

US data policy for Earth observation from space

NASA Technical Reports Server (NTRS)

Shaffer, Lisa Robock

1992-01-01

Distribution of data from U.S. Earth observations satellites is subject to different data policies and regulations depending on whether the systems in question are operational or experimental. Specific laws, regulations, and policies are in place for the distribution of satellite data from the National Oceanic and Atmospheric Administration (NOAA) operational environmental satellites and from NASA experimental systems. There is a government wide policy for exchange of data for global change research. For the Earth Observing System (EOS) and its international partner programs, a set of data exchange principles is nearing completion. The debate over the future of the LANDSAT program in the U.S. will impact policy for the programs, but the outcome of the debate is not yet known.

Earth’s Rotational Deceleration: Determination of Tidal Friction Independent of Timescales

NASA Astrophysics Data System (ADS)

Deines, Steven D.; Williams, Carol A.

2016-04-01

This paper determines Earth's rotational deceleration without relying on atomic or ephemeris timescales. Earth's rotation defines the civil time standard called Universal Time (UT). Our previous paper did not examine tidal friction in depth when analyzing the timescale divergence between UT and International Atomic Time (TAI). We examine all available paleontological fossils and deposits for the direct measurements of Earth's past rotation rates, because that record includes all contributing effects. We examine paleontological reports that date Earth's rotation rate using corals, bivalves, brachiopods, rhythmites, and stromatolites. Contributions that vary Earth's moment of inertia, such as continental plate drifts, coastline changes, ice age formations, and viscous glacial rebounds, are superimposed with the secular deceleration. The average deceleration of Earth's rotation rate from all available fossil data is found to be (5.969 ± 1.762) × 10-7 rad yr-2. Our value is 99.8% of the total rotational deceleration determined by Christodoulidis et al., who used artificial satellite data, and our value is 96.6% of the expected tidal friction value obtained by Stephenson and Morrison. Taking the derivative of conserved angular momentum, the predicted lunar orbital deceleration caused by the average rotational deceleration corresponds closely to lunar models. When evaluating the significant time gaps between UT and TAI, Earth's rotational deceleration is a minor contributing factor. Also, the secular deceleration rate is necessary to correctly date ancient astronomical events. We strongly encourage that more ocean paleontological evidence be found to supplement the record to separate the many periodic variations embedded in these data.

Earth Observation

NASA Image and Video Library

2013-07-04

ISS036-E-015342 (4 July 2013) --- A number of Quebec, Canada wildfires southeast of James Bay were recorded as part of a series of photographs taken and downlinked to Earth on July 4 by the Expedition 36 crew members aboard the International Space Station.

Earth Observation

NASA Image and Video Library

2013-07-04

ISS036-E-015335 (4 July 2013) --- A number of Quebec, Canada wildfires southeast of James Bay were recorded as part of a series of photographs taken and downlinked to Earth on July 4 by the Expedition 36 crew members aboard the International Space Station.

Inner Core Rotation from Geomagnetic Westward Drift and a Stationary Spherical Vortex in Earth's Core

NASA Technical Reports Server (NTRS)

Voorhies, Coerte V.

1998-01-01

The idea that geomagnetic westward drift indicates convective leveling of the planetary momentum gradient within Earth's core is pursued in search of a differentially rotating mean state, upon which various oscillations and secular effects might be superimposed. The desired state conforms to roughly spherical boundary conditions, minimizes dissipative interference with convective cooling in the bulk of the core, yet may aid core cooling by depositing heat in the uppermost core and lower mantle. The variational calculus of stationary dissipation applied to a spherical vortex within the core yields an interesting differential rotation profile, akin to spherical Couette flow bounded by thin Hartmann layers. Four boundary conditions are required. To concentrate shear induced dissipation near the core-mantle boundary, these are taken to be: (i) no-slip at the core-mantle interface; (ii) geomagnetically estimated bulk westward flow at the base of the core-mantle boundary layer; (iii) no-slip at the inner-outer core interface; and, to describe magnetic locking of the inner core to the deep outer core; (iv) hydrodynamically stress-free at the inner-outer core boundary. By boldly assuming the axial core angular momentum anomaly to be zero, the super-rotation of the inner core relative to the mantle is calculated to be at most 1.5 deg./yr.

Inner Core Rotation from Geomagnetic Westward Drift and a Stationary Spherical Vortex in Earth's Core

NASA Technical Reports Server (NTRS)

Voorhies, C. V.

1999-01-01

The idea that geomagnetic westward drift indicates convective leveling of the planetary momentum gradient within Earth's core is pursued in search of a differentially rotating mean state, upon which various oscillations and secular effects might be superimposed. The desired state conforms to roughly spherical boundary conditions, minimizes dissipative interference with convective cooling in the bulk of the core, yet may aide core cooling by depositing heat in the uppermost core and lower mantle. The variational calculus of stationary dissipation applied to a spherical vortex within the core yields an interesting differential rotation profile akin to spherical Couette flow bounded by thin Hartmann layers. Four boundary conditions are required. To concentrate shear induced dissipation near the core-mantle boundary, these are taken to be: (i) no-slip at the core-mantle interface; (ii) geomagnetically estimated bulk westward flow at the base of the core-mantle boundary layer; (iii) no-slip at the inner-outer core interface; and, to describe magnetic locking of the inner core to the deep outer core, (iv) hydrodynamically stress-free at the inner-outer core boundary. By boldly assuming the axial core angular momentum anomaly to be zero, the super-rotation of the inner core is calculated to be at most 1.5 degrees per year.

Observations on Rotating Cavitation and Cavitation Surge from the Development of the Fastrac Engine Turbopump

NASA Technical Reports Server (NTRS)

Zoladz, Thomas F.