GeoNEX: Earth observations from operational geostationary satellite systems

2020 ◽  
Author(s):  
Rama Nemani ◽  
Tsengdar Lee ◽  
Satya Kalluri ◽  
Kazuhito Ichii ◽  
Jong-Min Yeom
Keyword(s):  
High Frequency ◽  
Spectral Characteristics ◽  
Ocean Color ◽  
Geostationary Satellite ◽  
Data Sets ◽  
Satellite Systems ◽  
Earth Observations ◽  
Geostationary Satellites ◽  
Operational Decision Making ◽  
New Research

<p>The NASA Earth Exchange (NEX) team at Ames Research Center has embarked on a collaborative effort involving scientists from NASA, NOAA, JAXA/JMA, KMA/KARI exploring the feasibility of producing EOS-quality research products from operational geostationary satellite systems for climate monitoring. The latest generation of geostationary satellites (Himawari 8/9, GOES-16/17, Fengyun-4, GeoKompsat-2A) carry sensors that closely mimic the spatial and spectral characteristics of widely used polar-orbiting, global monitoring sensors such as MODIS and VIIRS. More importantly, they provide observations as frequently as 5-15 minutes. Data from various currently operating geostationary platforms provide a geo-ring of hyper-temporal, multispectral observations. Such high frequency observations, particularly when combined with data from polar orbiters, offer exciting possibilities for improving the retrieval of geophysical variables by overcoming cloud cover, enable studies of diurnally varying phenomena over land, in the atmosphere and the oceans, and help in operational decision-making in agriculture, hydrology and disaster management. Beyond the weather-focused geo-sensors, a number of new spectrometers are scheduled to be launched in the next five years in geostationary orbit to study atmospheric pollution (GEMS, TEMPO), ocean color (GOCI) and carbon cycling (GeoCARB). This talk will highlight new research, data sets, algorithms and computational platforms that utilize data from geostationary satellites to advance our ability to monitor the environment and create climate resiliency.</p>

scholarly journals Forty-three years of absolute gravity observations of the Fennoscandian postglacial rebound in Finland

2021 ◽  
Vol 95 (2) ◽  
Author(s):  
Mirjam Bilker-Koivula ◽  
Jaakko Mäkinen ◽  
Hannu Ruotsalainen ◽  
Jyri Näränen ◽  
Timo Saari
Keyword(s):  
Gravity Data ◽  
Gravity Change ◽  
Global Navigation Satellite Systems ◽  
Absolute Gravity ◽  
Data Sets ◽  
Postglacial Rebound ◽  
Land Uplift ◽  
Satellite Systems ◽  
Gravity Measurements ◽  
Global Navigation Satellite

AbstractPostglacial rebound in Fennoscandia causes striking trends in gravity measurements of the area. We present time series of absolute gravity data collected between 1976 and 2019 on 12 stations in Finland with different types of instruments. First, we determine the trends at each station and analyse the effect of the instrument types. We estimate, for example, an offset of 6.8 μgal for the JILAg-5 instrument with respect to the FG5-type instruments. Applying the offsets in the trend analysis strengthens the trends being in good agreement with the NKG2016LU_gdot model of gravity change. Trends of seven stations were found robust and were used to analyse the stabilization of the trends in time and to determine the relationship between gravity change rates and land uplift rates as measured with global navigation satellite systems (GNSS) as well as from the NKG2016LU_abs land uplift model. Trends calculated from combined and offset-corrected measurements of JILAg-5- and FG5-type instruments stabilized in 15 to 20 years and at some stations even faster. The trends of FG5-type instrument data alone stabilized generally within 10 years. The ratio between gravity change rates and vertical rates from different data sets yields values between − 0.206 ± 0.017 and − 0.227 ± 0.024 µGal/mm and axis intercept values between 0.248 ± 0.089 and 0.335 ± 0.136 µGal/yr. These values are larger than previous estimates for Fennoscandia.

scholarly journals A Mine of Information: Can Sports Analytics Provide Wisdom From Your Data?

2017 ◽  
Vol 12 (7) ◽  
pp. 851-855 ◽  
Author(s):  
Louis Passfield ◽  
James G. Hopker
Keyword(s):  
Web Sites ◽  
Large Data ◽  
Objective Evaluation ◽  
Large Data Sets ◽  
Data Sets ◽  
Competitive Strategies ◽  
Data Repositories ◽  
Sports Analytics ◽  
Sport And Exercise ◽  
New Research

This paper explores the notion that the availability and analysis of large data sets have the capacity to improve practice and change the nature of science in the sport and exercise setting. The increasing use of data and information technology in sport is giving rise to this change. Web sites hold large data repositories, and the development of wearable technology, mobile phone applications, and related instruments for monitoring physical activity, training, and competition provide large data sets of extensive and detailed measurements. Innovative approaches conceived to more fully exploit these large data sets could provide a basis for more objective evaluation of coaching strategies and new approaches to how science is conducted. An emerging discipline, sports analytics, could help overcome some of the challenges involved in obtaining knowledge and wisdom from these large data sets. Examples of where large data sets have been analyzed, to evaluate the career development of elite cyclists and to characterize and optimize the training load of well-trained runners, are discussed. Careful verification of large data sets is time consuming and imperative before useful conclusions can be drawn. Consequently, it is recommended that prospective studies be preferred over retrospective analyses of data. It is concluded that rigorous analysis of large data sets could enhance our knowledge in the sport and exercise sciences, inform competitive strategies, and allow innovative new research and findings.

Precise carrier phase altimetry over lakes using dual-frequency reflected signals of the Global Navigation Satellite Systems (GNSS)

2021 ◽  
Author(s):  
Estel Cardellach ◽  
Weiqiang Li ◽  
Dallas Masters ◽  
Takayuki Yuasa ◽  
Franck Borde ◽  
...  
Keyword(s):  
Sea Ice ◽  
Carrier Phase ◽  
Radio Occultation ◽  
Global Navigation Satellite Systems ◽  
Data Sets ◽  
Dual Frequency ◽  
Effective Wavelength ◽  
Raw Data ◽  
Satellite Systems ◽  
Global Navigation Satellite

<p>Recently, different studies have shown evidence of signals transmitted by the Global Navigation Satellite Systems (GNSS), coherently reflected over some parts of the ocean, and received from cubesats. In particular, strong coherent scattering has been reported in regions with low water surface roughness as those near continental masses and in atolls. Over open ocean, few coherent signals were reported to be found, although the data sets were somewhat limited and certainly not exhaustive. The level of coherence in reflected GNSS signals depends on the roughness of the  surface (i.e. significant wave height and small scale ripples and waves induced by the wind), the viewing geometry (i.e. incidence angle, or equivalently, elevation angle of the GNSS satellite as seen from the point of reflection), propagation effects (namely ionospheric disturbances) and on the frequency (i.e. particular GNSS band, like L1/E1, L2 or L5/E5). These coherent measurements over ocean follow earlier evidence of coherent GNSS reflections over sea ice which date back to 2005, the time of UK-DMC mission. More recently, Sea Ice Thickness (SIT) retrievals have also been carried out with this technique, at an accuracy comparable to that of SMOS.</p><p>All the observations referred so far were done at a single frequency, L1/E1. So, there is an interest to explore the coherence at the other main GNSS bands, i.e. L2 and L5/E5 as well as to the widelane combinations between them (linear combinations of carrier-phase measurements, of longer effective wavelength). Spire Global radio occultation cubesats work at L1 and L2 frequency bands, and therefore provide unique dual-frequency raw data sets of reflected signals over open ocean, sea ice and inland water bodies. With these, it is possible to study the coherence of these targets at each of the bands and at their widelane combination, as well as the performance of altimetric retrievals at grazing angles of observation (very slant geometries, which facilitate coherence properties of the scattering). The dual-frequency observations can correct the ionospheric effects, and their widelane combinations, of longer effective wavelength, might expand the conditions for coherence. The fact that this new approach is fully compatible with small GNSS radio occultation payloads and missions, might represent a low cost source of precise altimetry to complement larger dedicated missions.</p><p>An ESA research study involving Spire Global and IEEC aims at studying this new potential altimetric technique. Raw data acquisitions from limb-looking antennas of Spire’s cubesat constellation were selected to be geographically and time collocated with ESA Sentinel 3A and 3B passes in order to compare the results of coherence and altimetry. For this study, the raw data at two frequencies, acquired at 6.2 Mbps, are shifted to intermediate frequencies and downloaded to the ground without any further processing. In-house software receivers are then applied to generate the reflected echoes or waveforms, and to track the phase of the carrier signals. Precise altimetry (a few cm in 20 ms integration) is then possible from these observables. The results of this activity will be shown, focusing on altimetric retrievals over large lakes.</p>

scholarly journals Reliability Evaluation of the Joint Observation of Cloud Top Height by FY-4A and HIMAWARI-8

2021 ◽  
Vol 13 (19) ◽  
pp. 3851
Author(s):  
Qinghui Li ◽  
Xuejin Sun ◽  
Xiaolei Wang
Keyword(s):  
Measurement Method ◽  
Satellite Observation ◽  
Geostationary Satellite ◽  
Cloud Type ◽  
Surface Type ◽  
Geostationary Satellites ◽  
Good Consistency ◽  
Passive Sensors ◽  
Cloud Optical Thickness ◽  
Important Measurement

It is well known that the measurement of cloud top height (CTH) is important, and a geostationary satellite is an important measurement method. However, it is difficult for a single geostationary satellite to observe the global CTH, so joint observation by multiple satellites is imperative. We used both active and passive sensors to evaluate the reliability of joint observation of geostationary satellites, which includes consistency and accuracy. We analyzed the error of CTH of FY-4A and HIMAWARI-8 and the consistency between the two satellites and conducted research on the problem of missing measurement (Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO) has CTH data, but FY-4A/HIMAWARI-8 does not) of the two satellites. The results show that FY-4A and HIMAWARI-8 have good consistency and can be jointly observed, but the measurement of CTH of FY-4A and HIMAWARI-8 has large errors, and the error of FY-4A is greater than that of HIMAWIRI-8. The error of CTH is affected by the CTH, cloud optical thickness (COT) and cloud type, and the consistency between the two satellites is mainly affected by the cloud type. FY-4A and HIMAWARI-8 have the problem of missing measurement. The missing rate of HIMAWARI-8 is greater than that of FY-4A, and the missing rate is not affected by the CTH, COT and surface type. Therefore, although FY-4A and HIMAWARI-8 have good consistency, the error of CTH and the problem of missing measurement still limit the reliability of their joint observation.

scholarly journals Observation and a numerical study of gravity waves during tropical cyclone Ivan~(2008)

2013 ◽  
Vol 13 (4) ◽  
pp. 10757-10807 ◽  
Author(s):  
F. Chane Ming ◽  
C. Ibrahim ◽  
S. Jolivet ◽  
P. Keckhut ◽  
Y.-A. Liou ◽  
...  
Keyword(s):  
Tropical Cyclone ◽  
Gravity Waves ◽  
High Frequency ◽  
Lower Stratosphere ◽  
Numerical Study ◽  
Wide Spectrum ◽  
Spectral Characteristics ◽  
Background Wind ◽  
Quasi Biennial Oscillation ◽  
North East

Abstract. Activity and spectral characteristics of gravity-waves (GWs) are analyzed during tropical cyclone (TC) Ivan (2008) in the troposphere and lower stratosphere using radiosonde and GPS radio occultation data, ECMWF outputs and simulations of French numerical model Meso-NH with vertical resolution varying between 150 m near the surface and 500 m in the lower stratosphere. Conventional methods for GW analysis and signal and image processing tools provide information on a wide spectrum of GWs with horizontal wavelengths of 40–1800 km and short vertical wavelengths of 0.6–10 km respectively and periods of 20 min–2 days. MesoNH model, initialized with Aladin-Réunion analyses, produces realistic and detailed description of TC dynamics, GWs, variability of the tropospheric and stratospheric background wind and TC rainband characteristics at different stages of TC Ivan. In particular a dominant eastward propagating TC-related quasi-inertia GW is present during intensification of TC Ivan with horizontal and vertical wavelengths of 400–600 km and 1.5–3.5 km respectively during intensification. A wavenumber-1 vortex Rossby wave is identified as a source of this medium-scale mode while short-scale modes located at north-east and south-east of the TC could be attributed to strong localized convection in spiral bands resulting from wavenumber-2 vortex Rossby waves. Meso-NH simulations also reveal high-frequency GWs with horizontal wavelengths of 20–80 km near the TC eye and high-frequency GWs-related clouds behind TC Ivan. In addition, GWs produced during landfall are likely to strongly contribute to background wind in the middle and upper troposphere as well as the stratospheric quasi-biennial oscillation.

A shielded and robust LTCC BGA-interconnect for Ka-band satellite flight hardware

2012 ◽  
Vol 2012 (CICMT) ◽  
pp. 000082-000087
Author(s):  
Tobias Klein ◽  
Carsten Günner ◽  
Reinhard Kulke
Keyword(s):  
High Frequency ◽  
High Importance ◽  
Ka Band ◽  
Small Systems ◽  
Satellite Systems ◽  
Modular Concept ◽  
High Frequency Operation ◽  
Flight Hardware ◽  
Interconnect Technology

The complexity of today's satellite systems is ever-growing and system weight and size of the subcomponents are becoming even more critical as the number of channels increases. A possible solution for achieving small systems, while maintaining reliability, is the use of the LTCC process. The so-called Keramis technology is a modular concept, where a number of small, hermetically sealed LTCC modules are connected on a carrier substrate. For these systems, the interconnect technology that connects the different LTCCs is of high importance. This paper presents a novel BGA interconnect for high frequency operation up to 40 GHz.

Improving the Antinoise Ability of DNNs via a Bio-Inspired Noise Adaptive Activation Function Rand Softplus

2019 ◽  
Vol 31 (6) ◽  
pp. 1215-1233 ◽  
Author(s):  
Yunhua Chen ◽  
Yingchao Mai ◽  
Jinsheng Xiao ◽  
Ling Zhang
Keyword(s):  
Facial Expression ◽  
Learning Community ◽  
Activation Function ◽  
The Other ◽  
Data Sets ◽  
Expression Recognition ◽  
Activation Functions ◽  
Response Process ◽  
Catching Up ◽  
New Research

Although deep neural networks (DNNs) have led to many remarkable results in cognitive tasks, they are still far from catching up with human-level cognition in antinoise capability. New research indicates how brittle and susceptible current models are to small variations in data distribution. In this letter, we study the stochasticity-resistance character of biological neurons by simulating the input-output response process of a leaky integrate-and-fire (LIF) neuron model and proposed a novel activation function, rand softplus (RSP), to model the response process. In RSP, a scale factor [Formula: see text] is employed to mimic the stochasticity-adaptability of biological neurons, thereby enabling the antinoise capability of a DNN to be improved by the novel activation function. We validated the performance of RSP with a 19-layer residual network (ResNet) and a 19-layer visual geometry group (VGG) on facial expression recognition data sets and compared it with other popular activation functions, such as rectified linear units (ReLU), softplus, leaky ReLU (LReLU), exponential linear unit (ELU), and noisy softplus (NSP). The experimental results show that RSP is applied to VGG-19 or ResNet-19, and the average recognition accuracy under five different noise levels exceeds the other functions on both of the two facial expression data sets; in other words, RSP outperforms the other activation functions in noise resistance. Compared with the application in ResNet-19, the application of RSP in VGG-19 can improve a network's antinoise performance to a greater extent. In addition, RSP is easier to train compared to NSP because it has only one parameter to be calculated automatically according to the input data. Therefore, this work provides the deep learning community with a novel activation function that can better deal with overfitting problems.

Kappa (κ) in the 2011 Great East Japan Earthquake

2020 ◽  
Vol 14 (06) ◽  
pp. 2050024
Author(s):  
Zhengru Tao ◽  
Xinyan Wang ◽  
Baihui Zhu ◽  
Tao Shang
Keyword(s):  
High Frequency ◽  
Site Response ◽  
Epicentral Distance ◽  
Soft Soil ◽  
Statistical Significance ◽  
Great East Japan Earthquake ◽  
Propagation Path ◽  
Data Sets ◽  
Borehole Data ◽  
Nonlinear Site Response

Kappa ([Formula: see text]) describes the amplitude decay of acceleration Fourier spectrum at high frequencies. Using the records of K-NET and KiK-net stations during the mainshock of the 2011 Great East Japan Earthquake, we examine if the typical measurement method of [Formula: see text] can be extended to this size of event and how propagation path and site condition affect [Formula: see text]. The strength of the linear relationship between epicentral distance and [Formula: see text] is the most apparent in the KiK-net borehole data; for other data sets, the statistical significance of the best-fitting logarithmic model is more tenuous. Our study on site effects reveals that high-frequency amplitudes diminish about 20% at soft soil stations than they do at hard rock stations. The effect on high-frequency filters is around diminution in most cases. And, the effect of nonlinear site response on [Formula: see text] values can be observed.

scholarly journals Defining research priorities in dystonia

Neurology ◽  
2020 ◽  
Vol 94 (12) ◽  
pp. 526-537 ◽  
Author(s):  
Codrin Lungu ◽  
Laurie Ozelius ◽  
David Standaert ◽  
Mark Hallett ◽  
Beth-Anne Sieber ◽  
...  
Keyword(s):  
Research Priorities ◽  
Large Data ◽  
Therapeutic Interventions ◽  
Research Progress ◽  
Data Sets ◽  
Cellular Mechanisms ◽  
Research Technology ◽  
Current State ◽  
History Of ◽  
New Research

ObjectiveDystonia is a complex movement disorder. Research progress has been difficult, particularly in developing widely effective therapies. This is a review of the current state of knowledge, research gaps, and proposed research priorities.MethodsThe NIH convened leaders in the field for a 2-day workshop. The participants addressed the natural history of the disease, the underlying etiology, the pathophysiology, relevant research technologies, research resources, and therapeutic approaches and attempted to prioritize dystonia research recommendations.ResultsThe heterogeneity of dystonia poses challenges to research and therapy development. Much can be learned from specific genetic subtypes, and the disorder can be conceptualized along clinical, etiology, and pathophysiology axes. Advances in research technology and pooled resources can accelerate progress. Although etiologically based therapies would be optimal, a focus on circuit abnormalities can provide a convergent common target for symptomatic therapies across dystonia subtypes. The discussions have been integrated into a comprehensive review of all aspects of dystonia.ConclusionOverall research priorities include the generation and integration of high-quality phenotypic and genotypic data, reproducing key features in cellular and animal models, both of basic cellular mechanisms and phenotypes, leveraging new research technologies, and targeting circuit-level dysfunction with therapeutic interventions. Collaboration is necessary both for collection of large data sets and integration of different research methods.

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