Terrestrial Observations Research Articles

Historical observation impact assessments for EUMETNET using the ALADIN/HU limited area model

Two historical Observing System Experiment (OSE) studies using the ALADIN limited area model and its assimilation system are described. The first study, using an OSE scenario that minimizes the impacts of observations through the lateral boundary conditions, demonstrated the importance of each assimilated terrestrial (radiosonde, aircraft, and wind profiler) observations on the analyses and short-range forecasts of the ALADIN/HU model and proved evidence, that the role of conventional observations cannot be even partly taken over by satellite measurements without degradation of the forecast quality. The second study demonstrated that the assimilation of radiosonde observations remains indispensable even with a progressively increasing amount of aircraft measurements.

Developing Prototype Simulants for Surface Materials and Morphology of Near Earth Asteroid 2016 HO3

There are a variety of applications for asteroid simulants in asteroid studies for science advances as well as technology maturation. For specific purpose, it usually requires purpose-specialized simulant. In this study, we designed and developed a set of prototype simulants as S-type asteroid surface materials analogue based on H, L, and LL ordinary chondrites’ mineralogy and terrestrial observations of near-earth asteroid 2016 HO3, which is the Chinese sample return mission target. These simulants are able to simulate morphology and reflectance characteristics of asteroid (469219) 2016 HO3 and, thus, to be used for engineering evaluation of the optical navigation system and the sampling device of the spacecraft during the mission phase. Meanwhile, these prototype simulants are easily to modify to reflect new findings on the asteroid surface when the spacecraft makes proximate observations.

The Generalization of the Periodic Table: The 'Periodic Table' of 'Dark Matter'

The Generalization of the Periodic Table: The 'Periodic Table' of 'Dark Matter'

Gravimetric geoid modeling from the combination of satellite gravity model, terrestrial and airborne gravity data: a case study in the mountainous area, Colorado

Constructing a high-precision and high-resolution gravimetric geoid model in the mountainous area is a quite challenging task because of the lack of terrestrial gravity observations, rough topography and the geological complexity. One way out is to use high-quality and well-distributed satellite and airborne gravity data to fill the gravity data gaps; thus, the proper combination of heterogeneous gravity datasets is critical. In a rough topographic area in Colorado, we computed a set of gravimetric geoid models based on different combination modes of satellite gravity models, terrestrial and airborne gravity data using the spectral combination method. The gravimetric geoid model obtained from the combination of satellite gravity model GOCO06S and terrestrial gravity data agrees with the GPS leveling measured geoid heights at 194 benchmarks in 5.8 cm in terms of the standard deviation of discrepancies, and the standard deviation reduces to 5.3 cm after including the GRAV-D airborne gravity data collected at ~ 6.2 km altitude into the data combination. The contributions of airborne gravity data to the signal and accuracy improvements of the geoid models were quantified for different spatial distribution and density of terrestrial gravity data. The results demonstrate that, although the airborne gravity survey was flown at a high altitude, the additions of airborne gravity data improved the accuracies of geoid models by 13.4%–19.8% in the mountainous area (elevations > 2000 m) and 12.7%–21% (elevations < 2000 m) in the moderate area in the cases of terrestrial gravity data spacings are larger than 15 km.

Comparative Analysis of Terrestrial and Satellite Observations of Photospheric Magnetic Field in an Appendix to Simulation of Parameters of Coronal Holes and Solar Wind

Data from observations of the photospheric magnetic field at a number of ground stations (STOP, WSO, GONG) and by the SDO/HMI satellite for 2014–2019 are examined in terms of the accuracy of the model calculations of the speed of calm solar wind and the areas of coronal holes obtained on their basis. A high positive correlation was found (R > 0.5) between the simulation results and satellite observations (ACE, SDO/AIA193) for separate time periods. The best results in the modeling of the speed of the calm solar wind are given by the data from the ground stations WSO and STOP (Kislovodsk Mountain Astronomical Station, 2014). The temporal variability of the empirical coefficients of the model used in the forecasts was determined.

The Relic Neutrino Composition as Seen from Earth

Being generated, the relic neutrino background contained equal fractions of electron $\nu_e$, muon $\nu_\mu$, and taon $\nu_\tau$ neutrinos. We show that the gravitational field of our Galaxy and other nearby cosmic objects changes this composition near the Solar System, enriching it with the heaviest neutrino $nu_3$. This mass state is almost free of the electron component (only $\sim 2\%$ of $\nu_e$) and contains more muon component than the tau one. As a result, the relic background becomes enriched with taon and particularly muon neutrinos. The electron relic neutrinos are the rarest for a terrestrial observer: instead of $1/3$, the relic background may contain only $\gtrsim 20\%$ of them.

Redshift Anomaly on the Solar Disk as Multiple Interactions between Photons and Electrons

This paper analyses the center-to-limb problem of the Sun encountered in the solar lines by using for the first time the New Tired Light theory based on photons of light losing energy due to interaction with electrons. For this scope, a detailed geometrical orbital model on the scale was created in order to trace back all physical characteristics of the Earth orbiting the Sun for three days in the year 1946, when the redshift measurements were taken. This paper suggests that, since the space between the Sun and the Earth consists of a high exponential distribution of electrons, it works out as a medium for the photons of light. Indeed, in the line of sight of a terrestrial observer, the distance between the Sun and the Earth is greater at the limb than in the center, valid for each orbital position. Accordingly, the interactions between photons and electrons cause a slight difference in redshift along the entire solar disk, matching the observational data. An important factor is the definition of objective criteria for the radial velocity component of the solar granules, whose variable values refer, in turn, to existing observational data, crucial for the success of the study. The redshift anomaly on the solar disk has been repeatedly detected in many scientific researches but only a few attempts so far, mostly based on parametrized models, have been done to give a reliable explanation to the measurements.

Changes in urban green spaces’ value perception: A meta-analytic benefit transfer function for European cities

We estimate a meta-regression of the willingness to pay (WTP) for green spaces in European urban and peri-urban areas obtained from contingent valuation (CV) studies to construct a benefit transfer (BT) function. Compared to previous studies that estimated meta-regression for urban green spaces, we introduce two main novelties. Firstly, we focus exclusively on Europe to reduce the heterogeneity due to unobservable factors that affect the estimates and their transferability. Secondly, we use urban socio-economic indicators and land-use data derived from terrestrial observations as proxies for the supply and demand of ecosystem services at the local level, allowing interactions between these variables and the specific characteristics of the site valued. We demonstrate that both approaches improve the accuracy of the estimates and, hence, the validity of the transferred values.

The source-end method of remote sensing information quality enhancement and the physical basis of geoscience-photoelectric parameters connection

<p indent="0mm">The improvement of spatial information quality is the basis and goal of the quantitative development of high-resolution remote sensing. This paper presents a new method for improving the quality of the remote sensing information obtained from the source of an imaging system; this method also realizes the mutual conversion of the geoscience and optical parameters. By continuously adjusting the photoelectric parameters of the imaging sensor, it was possible to minimize the observation error of the terrestrial object observation image. By adjusting the photoelectric physical parameters of the instrument, the quality of the remote sensing information was improved. The image digital number (<italic>DN</italic>) value obtained by field calibration experiments was used to adjust the photoelectric parameters by using the correction model <italic>DN</italic>=<italic>kL</italic>+<italic>g</italic> of the ground object <italic>L</italic>. When the real fitting coefficient <italic>k</italic> approached 1, and the deviation <italic>g</italic> approached 0, the image<italic> DN</italic> value approached the real value <italic>L</italic> of the ground object. Furthermore, when <italic>k</italic> deviated from 1 and <italic>g</italic> from 0, the observation error increased, and the instrument degenerated. The deteriorated components of the instrument could be obtained using the photoelectric parametric decomposition equation, which can be used to verify the quality of the instrument and to improve the quality of spatial information. The new mechanism for measuring the load quality of the remote sensing imaging based on the geo-optoelectronic parameter conversion and penetration can overcome the technical bottleneck of non-correlation between the surface parameters and photoelectric parameters of the imaging system. This mechanism solves the difficulty involved in measuring the remote sensing imaging error equivalently from the source of the photoelectric imaging system. The theory and experiment proved that the mechanism was effective and feasible.

Impactite dykes in impact crater central uplifts: Insights from Negril crater, Mars

Negril crater is a 52 km complex crater located north of Syrtis Major, Mars. The central uplift of Negril crater is remarkably well-exposed and contains one of the best examples of dykes associated with a Martian crater. This study aims to characterize the dykes within the central uplift and determine if they are impactite dykes that formed as a part of the impact process or whether they are pre-existing mineral veins or volcanic dykes that were uplifted. This study also attempts to put the geology of the uplift into the proper stratigraphic context of the regional geology in the vicinity of Jezero crater. The uplift consists of two major geomorphologic units: the uplifted fractured and brecciated massive bedrock crosscut by linear ridges and dykes, and a dark-toned clast-rich to clast-poor unit that coats the central uplift and crater floor, interpreted as impact melt rock. The uplift is quite diverse with respect to its morphology and spectral characteristics, exhibiting bedrock with spectral signatures consistent with a low-calcium pyroxene, Fe/Mg-bearing phyllosilicates and a few occurrences of a plagioclase feldspar, dykes with an olivine-bearing signature, and additional Fe/Mg-bearing phyllosilicates associated with pervasive light-toned ridges and mounds. The ridges crosscut the impact melt rock and are consistent with impact-generated hydrothermal alteration. Two varieties of dykes occurring within the uplift that have a complex cross-cutting relationship, indicating they formed syngenetically with respect to each other. The morphology, orientation and composition of the dykes suggest they may represent impact melt dykes rather than pre-existing dykes that were uplifted. This interpretation is also based on comparisons made with terrestrial observations. Finally, the uplifted fractured bedrock is potentially related to the extensive Fe/Mg phyllosilicate-bearing basement units in the Nili Fossae region that may be related to the formation and evolution of the Isidis Basin.

Application of Robust Estimation Method for Establishing 3D Combined Terrestrial and GNSS Network: A case of a Quarry in Lang Son, Vietnam

Recently, in Vietnam, the detection of geodetic measurements that contain rough errors as well as such data processing method has been considered as a key step in geodetic data processing, especially for large geodetic networks with many different types of measurements like 3D - Global Navigation Satellite Systems (GNSS) network. On the other hand, mines in Vietnam often have complex terrains, so it is necessary to apply modern and flexible surveying methods in combination with ground and space measurements to build 3D coordinates control networks for management and exploitation to ensure sustainable development. Therefore, this research developed a Robust estimation method based on empirical weighting function for establishing 3D geodetic network combining terrestrial observation and GNSS vectors. The experiment on processing the combined network in Lang Son limestone quarry, Vietnam showed that the proposed method could be an effective solution for processing 3D terrestrial – GNSS geodetic network for mine surveying in Vietnam.

Stochastic Properties of Confidence Ellipsoids after Least Squares Adjustment, Derived from GUM Analysis and Monte Carlo Simulations

In this paper stochastic properties are discussed for the final results of the application of an innovative approach for uncertainty assessment for network computations, which can be characterized as two-step approach: As the first step, raw measuring data and all possible influencing factors were analyzed, applying uncertainty modeling in accordance with GUM (Guide to the Expression of Uncertainty in Measurement). As the second step, Monte Carlo (MC) simulations were set up for the complete processing chain, i.e., for simulating all input data and performing adjustment computations. The input datasets were generated by pseudo random numbers and pre-set probability distribution functions were considered for all these variables. The main extensions here are related to an analysis of the stochastic properties of the final results, which are point clouds for station coordinates. According to Cramer’s central limit theorem and Hagen’s elementary error theory, there are some justifications for why these coordinate variations follow a normal distribution. The applied statistical tests on the normal distribution confirmed this assumption. This result allows us to derive confidence ellipsoids out of these point clouds and to continue with our quality assessment and more detailed analysis of the results, similar to the procedures well-known in classical network theory. This approach and the check on normal distribution is applied to the local tie network of Metsähovi, Finland, where terrestrial geodetic observations are combined with Global Navigation Satellite System (GNSS) data.

Integration of airborne gravimetry data filtering into residual least-squares collocation: example from the 1\xa0cm geoid experiment

Low-pass filters are commonly used for the processing of airborne gravity observations. In this paper, for the first time, we include the resulting correlations consistently in the functional and stochastic model of residual least-squares collocation. We demonstrate the necessity of removing high-frequency noise from airborne gravity observations, and derive corresponding parameters for a Gaussian low-pass filter. Thereby, we intend an optimal combination of terrestrial and airborne gravity observations in the mountainous area of Colorado. We validate the combination in the frame of our participation in ‘the 1 cm geoid experiment’. This regional geoid modeling inter-comparison exercise allows the calculation of a reference solution, which is defined as the mean value of 13 independent height anomaly results in this area. Our result performs among the best and with 7.5 mm shows the lowest standard deviation to the reference. From internal validation we furthermore conclude that the input from airborne and terrestrial gravity observations is consistent in large parts of the target area, but not necessarily in the highly mountainous areas. Therefore, the relative weighting between these two data sets turns out to be a main driver for the final result, and is an important factor in explaining the remaining differences between various height anomaly results in this experiment.

GLOBE Observer Data: 2016-2019.

This technical report summarizes the GLOBE Observer data set from 1 April 2016 to 1 December 2019. GLOBE Observer is an ongoing NASA‐sponsored international citizen science project that is part of the larger Global Learning and Observations to Benefit the Environment (GLOBE) Program, which has been in operation since 1995. GLOBE Observer has the greatest number of participants and geographic coverage of the citizen science projects in the Earth Science Division at NASA. Participants use the GLOBE Observer mobile app (launched in 2016) to collect atmospheric, hydrologic, and terrestrial observations. The app connects participants to satellite observations from Aqua, Terra, CALIPSO, GOES, Himawari, and Meteosat. Thirty‐eight thousand participants have contributed 320,000 observations worldwide, including 1,000,000 georeferenced photographs. It would take an individual more than 13 years to replicate this effort. The GLOBE Observer app has substantially increased the spatial extent and sampling density of GLOBE measurements and more than doubled the number of measurements collected through the GLOBE Program. GLOBE Observer data are publicly available (at observer.globe.gov).

Can We Measure a COVID-19-Related Slowdown in Atmospheric CO2 Growth? Sensitivity of Total Carbon Column Observations

The COVID-19 pandemic is causing projected annual CO2 emission reductions up to −8% for 2020. This approximately matches the reductions required year on year to fulfill the Paris agreement. We pursue the question whether related atmospheric concentration changes may be detected by the Total Carbon Column Observing Network (TCCON), and brought into agreement with bottom-up emission-reduction estimates. We present a mathematical framework to derive annual growth rates from observed column-averaged carbon dioxide (XCO2) including uncertainties. The min–max range of TCCON growth rates for 2012–2019 was [2.00, 3.27] ppm/yr with a largest one-year increase of 1.07 ppm/yr for 2015/16 caused by El Niño. Uncertainties are 0.38 [0.28, 0.44] ppm/yr limited by synoptic variability, including a 0.05 ppm/yr contribution from single-measurement precision. TCCON growth rates are linked to a UK Met Office forecast of a COVID-19-related reduction of −0.32 ppm yr−2 in 2020 for Mauna Loa. The separation of TCCON-measured growth rates vs. the reference forecast (without COVID-19) is discussed in terms of detection delay. A 0.6 [0.4, 0.7]-yr delay is caused by the impact of synoptic variability on XCO2, including a ≈1-month contribution from single-measurement precision. A hindrance for the detection of the COVID-19-related growth rate reduction in 2020 is the ±0.57 ppm/yr uncertainty for the forecasted reference case (without COVID-19). Only assuming the ongoing growth rate reductions increasing year-on-year by −0.32 ppm yr−2 would allow a discrimination of TCCON measurements vs. the unperturbed forecast and its uncertainty—with a 2.4 [2.2, 2.5]-yr delay. Using no forecast but the max–min range of the TCCON-observed growth rates for discrimination only leads to a factor ≈2 longer delay. Therefore, the forecast uncertainties for annual growth rates must be reduced. This requires improved terrestrial ecosystem models and ocean observations to better quantify the land and ocean sinks dominating interannual variability.

Downward continuation of gravitational field quantities to an irregular surface by spectral weighting

In geophysical and geodetic studies, gravity inversion is typically performed such that observed gravity values are first continued downward onto a regular (planar, spherical or spheroidal) surface by solving an inverse integral transform, which originates from a classical solution to the first boundary-value problem in potential theory. A typical example is continuing gravity observed at the topographic surface down to the mean sea level (geoid). Nowadays, gravity-dedicated satellite missions and aerial gravimetry provide gravity data above the topographic surface in addition to classical terrestrial gravity observations. For specific purposes (such as gravity data combination and validation, or quasigeoid determination), satellite and aerial gravity observations have to be continued to the irregular topographic surface. In this study, we address this issue by formulating a functional model for a spectral downward continuation of selected gravitational field quantities to an irregular topographic surface. Moreover, we generalize this functional model to allow for transformation between different types of gravitational field quantities. In particular, we derive spectral weights for estimation of the disturbing potential or disturbing/anomalous gravity at the Earth’s surface by combining the first-, second- and third-order radial gradients of the disturbing potential (disturbing gradients). The correctness of the developed combined spectral estimator is verified in a closed-loop test based on synthetic satellite disturbing gradients. The combined spectral estimator is applied to simulated satellite disturbing gradients polluted by a realistic Gaussian noise. Results of the numerical experiments show that the combined spectral estimator puts the highest importance on the least polluted disturbing gradient, while the contribution of the least accurate disturbing gradient is negligible. An important advantage of this spectral combination method is that no matrix inversion with numerical instabilities requiring regularization is needed.

Antimatter as macroscopic dark matter

Antimatter macroscopic dark matter (macros) refers to a generic class of antimatter dark matter candidates that interact with ordinary matter primarily through annihilation with large cross-sections. A combination of terrestrial, astrophysical, and cosmological observations constrain a portion of the anti-macro parameter space. However, a large region of the parameter space remains unconstrained, most notably for nuclear-dense objects.

DETERMINATION OF SURFACE ROUGHNESS PARAMETER THROUGH AERIAL IMAGES IN WIND POWER PLANT INSTALLATION

The surface roughness parameter is an important parameter in the installation of a wind energy power plant and it varies depending on the dimensions and the distribution of the roughness elements on the land. Before the installation roughness maps indicate roughness of the surface has to be drawn. In today's applications, these maps are drawn approximately by WAsP software using the information obtained from the terrestrial observations belongs to experts. But this application is costly and time consuming and the assessment is based on limited land observations. In this study the surface roughness parameter is determined by digital image processing techniques from the digital images taken over aerial field. Thus it gives the opportunity to consider whole power plant surface into account with lower cost and time requirements over the traditional methods. Images used in the study are obtained from the Map General Command and MATLAB software platform is used. The study is based on the determination of the closure rates on the land by image segmentation method such as OTSU algorithm, fuzzy c-means and k-means algorithms. In order to evaluate the consistency of the results images are evaluated with ERDAS software. Obtained results showed the effectiveness of the study.

In situ evidence of thermally induced rock breakdown widespread on Bennu\u2019s surface

Rock breakdown due to diurnal thermal cycling has been hypothesized to drive boulder degradation and regolith production on airless bodies. Numerous studies have invoked its importance in driving landscape evolution, yet morphological features produced by thermal fracture processes have never been definitively observed on an airless body, or any surface where other weathering mechanisms may be ruled out. The Origins, Spectral Interpretation, Resource Identification, and Security–Regolith Explorer (OSIRIS-REx) mission provides an opportunity to search for evidence of thermal breakdown and assess its significance on asteroid surfaces. Here we show boulder morphologies observed on Bennu that are consistent with terrestrial observations and models of fatigue-driven exfoliation and demonstrate how crack propagation via thermal stress can lead to their development. The rate and expression of this process will vary with asteroid composition and location, influencing how different bodies evolve and their apparent relative surface ages from space weathering and cratering records.

History of On-Board Equipment Improvement for GNSS-A Observation With Focus on Observation Frequency

The Global Navigation Satellite System-Acoustic ranging combination technique (GNSS-A) is a seafloor geodetic technique that enables precise global seafloor positioning to detect subseafloor geophysical phenomena. The technique requires a sea surface observation platform that combines GNSS positioning and acoustic ranging. Currently, a survey vessel is used as the platform, which entails substantial financial and human resources costs, which makes increasing observation frequency difficult. It is possible to detect long-term average seafloor movement at the centimeter level, but it is difficult to detect short-term variation due to the insufficiency of observation frequency. The terrestrial GNSS observation network has detected temporal changes in crustal deformation fields. These precise observations provide useful information on the megathrust seismogenic zone. To detect such phenomena on the seafloor, the temporal resolution of the GNSS-A observation needs to be improved. Advances in vessel equipment technology are crucial for increasing observation frequency. In this paper, we review the historical development of the Japan Coast Guard’s GNSS-A observation system, focusing on technological developments of on-board equipment installed on a sea surface platform, and explain how such improvements have increased observation frequency over time. In the present, ranging frequency has improved from 40-60 s to 15-20 s by the introduction of the multiple ranging system, resulting in more frequent observations up to 5 times per year for an individual site.