Joint Discussion 6: Sun and Heliosphere - Challenges for Solar-Terrestrial Physics, Magneto-and Hydrodynamics

There is one astrophysical system, where the sites of a star’s mass loss can be localised and observed in detail, and where the behaviour of the resulting stellar wind in the star’s environment and around orbiting obstacles can be investigated in situ: it is the Sun, the heliosphere and the surroundings of planets — among the latter most prominently the terrestrial magnetosphere. Indeed, within a year or so a fleet of satellites equipped with sophisticated remote-sensing and in-situ instruments will make this astronomical paradigm, or more precisely, the solar-terrestrial system accessible to intensive, multi-disciplinary study.Four identical CLUSTER spacecraft, orbiting the Earth within the magnetosphere, the surrounding space and the particularly interesting plasma boundary layers will perform a three-dimensional in-situ study of plasma-heating, particle-acceleration and other small-scale plasma processes (Schmidt and Goldstein,1988). A number of other missions — some of them already in orbit, like GEOTAIL and WIND, some to be launched within one or two years, like INTERBALL and POLAR — will provide information about the Earth’s magnetosphere and the solar wind on larger spatial scales. These missions are described in a Brochure issued jointly by the European Space Agency, NASA, the Japanese Institute of Space and Astronomical Science and the Rssian Space Agency, which can be obtained from A. Pedersen at the above address.

Download Full-text

Helioseismology from space, the SOHO project

Symposium - International Astronomical Union ◽

10.1017/s007418090015867x ◽

1988 ◽

Vol 123 ◽

pp. 545-548

Author(s):

V. Domingo

Keyword(s):

Solar Wind ◽

Solar Corona ◽

European Space Agency ◽

Science Research ◽

Small Scale ◽

Heliospheric Observatory ◽

Space Agency ◽

Cluster A ◽

Physics Programme

As a cornerstone of its long term plan for space science research, the European Space Agency (ESA) is developing the Solar Terrestrial Physics Programme that consists of two parts: one, the Solar and Heliospheric Observatory (SOHO) for the study of the solar internal structure and the physics of the solar corona and the solar wind, and another, CLUSTER, a series of four spacecraft flying in formation to study small scale plasma phenomena in several regions of the magnetosphere and in the near Earth solar wind. The feasibility of the missions was demonstrated in Phase A studies carried out by industrial consortia under the supervision of ESA (1,2). According to the current plans an announcement of opportunity calling for instrument proposals will be issued by ESA during the first quarter of 1987. It is foreseen that the spacecraft will be launched by the end of 1994.

Download Full-text

A comparison between the two lobes of comet 67P/Churyumov–Gerasimenko based on D/H ratios in H2O measured with the Rosetta/ROSINA DFMS

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2482 ◽

2019 ◽

Vol 489 (4) ◽

pp. 4734-4740 ◽

Cited By ~ 4

Author(s):

Isaac R H G Schroeder ◽

Kathrin Altwegg ◽

Hans Balsiger ◽

Jean-Jacques Berthelier ◽

Michael R Combi ◽

...

Keyword(s):

Mass Spectrometer ◽

European Space Agency ◽

Cometary Nucleus ◽

The Other ◽

Appreciable Difference ◽

Space Agency ◽

Close Proximity ◽

Double Focusing ◽

Comet 67P

ABSTRACT The nucleus of the Jupiter-family comet 67P/Churyumov–Gerasimenko was discovered to be bi-lobate in shape when the European Space Agency spacecraft Rosetta first approached it in 2014 July. The bi-lobate structure of the cometary nucleus has led to much discussion regarding the possible manner of its formation and on how the composition of each lobe might compare with that of the other. During its two-year-long mission from 2014 to 2016, Rosetta remained in close proximity to 67P/Churyumov–Gerasimenko, studying its coma and nucleus in situ. Based on lobe-specific measurements of HDO and H2O performed with the ROSINA Double Focusing Mass Spectrometer (DFMS) on board Rosetta, the deuterium-to-hydrogen (D/H) ratios in water from the two lobes can be compared. No appreciable difference was observed, suggesting that both lobes formed in the same region and are homogeneous in their D/H ratios.

Download Full-text

The Rosetta Mission to Primitive Bodies of the Solar System

Symposium - International Astronomical Union ◽

10.1017/s0074180900046660 ◽

1994 ◽

Vol 160 ◽

pp. 381-394

Author(s):

Yves Langevin

Keyword(s):

Remote Sensing ◽

Solar System ◽

European Space Agency ◽

Time Span ◽

Main Belt ◽

Space Agency ◽

Rosetta Mission ◽

One Year ◽

Definition Of

The European Space Agency (ESA) has selected Rosetta as the next cornerstone mission, to be launched in 2003. The goal is to perfom one or more fly-bys to main belt asteroids, followed by a rendez-vous with an active comet. Advanced in situ analysis, both in the coma and on the surfaces of the nucleus, will be possible, as well as monitoring by remote sensing instruments of the nucleus and of the inner coma for a time span of more than one year, until perihelion. This paper outlines the scientific and technological choices done in the definition of the mission.

Download Full-text

Evaluation of the Performance of SM2RAIN-Derived Rainfall Products over Brazil

Remote Sensing ◽

10.3390/rs11091113 ◽

2019 ◽

Vol 11 (9) ◽

pp. 1113 ◽

Cited By ~ 9

Author(s):

Franklin Paredes-Trejo ◽

Humberto Barbosa ◽

Carlos A. C. dos Santos

Keyword(s):

Soil Moisture ◽

Pearson Correlation ◽

European Space Agency ◽

Rainfall Events ◽

Error Components ◽

Space Agency ◽

Daily Scale ◽

Bioclimatic Conditions ◽

Heavy Rainfall Events

Microwave-based satellite soil moisture products enable an innovative way of estimating rainfall using soil moisture observations with a bottom-up approach based on the inversion of the soil water balance Equation (SM2RAIN). In this work, the SM2RAIN-CCI (SM2RAIN-ASCAT) rainfall data obtained from the inversion of the microwave-based satellite soil moisture (SM) observations derived from the European Space Agency (ESA) Climate Change Initiative (CCI) (from the Advanced SCATterometer (ASCAT) soil moisture data) were evaluated against in situ rainfall observations under different bioclimatic conditions in Brazil. The research V7 version of the Tropical Rainfall Measurement Mission Multi-satellite Precipitation Analysis (TRMM TMPA) was also used as a state-of-the-art rainfall product with an up-bottom approach. Comparisons were made at daily and 0.25° scales, during the time-span of 2007–2015. The SM2RAIN-CCI, SM2RAIN-ASCAT, and TRMM TMPA products showed relatively good Pearson correlation values (R) with the gauge-based observations, mainly in the Caatinga (CAAT) and Cerrado (CER) biomes (R median > 0.55). SM2RAIN-ASCAT largely underestimated rainfall across the country, particularly over the CAAT and CER biomes (bias median < −16.05%), while SM2RAIN-CCI is characterized by providing rainfall estimates with only a slight bias (bias median: −0.20%), and TRMM TMPA tended to overestimate the amount of rainfall (bias median: 7.82%). All products exhibited the highest values of unbiased root mean square error (ubRMSE) in winter (DJF) when heavy rainfall events tend to occur more frequently, whereas the lowest values are observed in summer (JJA) with light rainfall events. The SM2RAIN-based products showed larger contribution of systematic error components than random error components, while the opposite was observed for TRMM TMPA. In general, both SM2RAIN-based rainfall products can be effectively used for some operational purposes on a daily scale, such as water resources management and agriculture, whether the bias is previously adjusted.

Download Full-text

Combining ExoMars’ Ma_MISS and Drill data

10.5194/epsc2020-882 ◽

2020 ◽

Author(s):

Alessandro Frigeri ◽

Maria Cristina De Sanctis ◽

Francesca Altieri ◽

Simone De Angelis ◽

Marco Ferrari ◽

...

Keyword(s):

Mechanical Properties ◽

Water Content ◽

Large Scale ◽

Mechanical Response ◽

European Space Agency ◽

Volcanic Rocks ◽

Space Agency ◽

Geophysical Imaging

The ExoMars Rover and Surface Platform planned for launch in 2022 is a large international cooperation between the European Space Agency and Roscosmos with a scientific contribution from NASA.&#160; Thales Alenia Space is the ExoMars mission industrial prime contractor.&#160; Besides sensors and instruments characterizing the surface at large scale, the ExoMars&#8217; rover Rosalind Franklin payload features some experiments devoted specifically to the characterization of the first few meters of the Martian subsurface. These experiments are particularly critical for the main ExoMars objective of detecting traces of present or past life forms on Mars, which may have been preserved within the shallow Martian underground [1]. Rosalind Franklin will be able to perform both non-invasive geophysical imaging of the underground [2] and subsurface in situ measurements thanks to the Drill unit installed on the rover. The Drill has been developed by Leonardo and its purposes are 1) to collect core samples to be analyzed in the Analytical Laboratory Drawer (ALD) onboard the Rover and 2) to drive the miniaturized spectrometer Ma_MISS within the borehole.&#160;&#160;&#160; Ma_MISS (Mars Multispectral Imager for Subsurface Studies, [3]) will collect mineralogic measurements from the rocks exposed into the borehole created by the Drill with a spatial resolution of 120 &#956;m down to 2 meters into the Martian subsurface. Rocks are composed of grains of minerals, and their reaction to an applied stress is related to the mechanical behavior of the minerals that compose the rock itself. The mechanical properties of a mineral depend mainly on the strength of the chemical bonds, the orientation of crystals, and the number of impurities in the crystal lattice. In this context, the integration of Ma_MISS measurements and drill telemetry are of great importance.&#160; The mechanical properties of rocks coupled with their mineralogic composition provide a rich source of information to characterize the nature of rocks being explored by ExoMars rover&#8217;s drilling activity. Within our study, we are starting to collect telemetry recorded during the Drill unit tests on several samples ranging from sedimentary to volcanic rocks with varying degrees of weathering and water content.&#160; In this first phase of the study, we focused our attention on the variation of torque and penetration speed between different samples, which have been found to be indicative of a particular type of rock or group of rocks and their water content.&#160;&#160; We are planning to analyze the same rocks with the Ma_MISS breadboard creating the link between the mineralogy and the mechanical response of the Drill.&#160;&#160;&#160;&#160;&#160;&#160; This will put the base for a more comprehensive and rich characterization of the in situ subsurface observation by Rosalind Franklin planned at Oxia Planum, Mars in 2023.&#160; &#160; Acknowledgments: We thank the European Space Agency (ESA) for developing the ExoMars Project, ROSCOSMOS and Thales Alenia Space for rover development, and Italian Space Agency (ASI) for funding the Ma_MISS experiment (ASI-INAF contract n.2017-48-H.0 for ExoMars MA_MISS phase E/science). &#160; References [1] Vago et al., 2017. Astrobiology, 17 6-7. [2] Ciarletti et al., 2017. Astrobiology, 17 6-7. [3] De Sanctis et al., 2017. Astrobiology, 17 6-7.

Download Full-text

On the accuracy of integrated water vapor observations and the potential for mitigating electromagnetic path delay error in InSAR

Atmospheric Measurement Techniques ◽

10.5194/amt-5-1015-2012 ◽

2012 ◽

Vol 5 (5) ◽

pp. 1015-1030 ◽

Cited By ~ 21

Author(s):

D. Cimini ◽

N. Pierdicca ◽

E. Pichelli ◽

R. Ferretti ◽

V. Mattioli ◽

...

Keyword(s):

Water Vapor ◽

Numerical Models ◽

European Space Agency ◽

Path Delay ◽

Gps Receivers ◽

Transmission Errors ◽

Vapor Sensing ◽

Space Agency ◽

Microwave Radiometers

Abstract. A field campaign was carried out in the framework of the Mitigation of Electromagnetic Transmission errors induced by Atmospheric Water Vapour Effects (METAWAVE) project sponsored by the European Space Agency (ESA) to investigate the accuracy of currently available sources of atmospheric columnar integrated water vapor measurements. The METAWAVE campaign took place in Rome, Italy, for the 2-week period from 19 September to 4 October 2008. The collected dataset includes observations from ground-based microwave radiometers and Global Positioning System (GPS) receivers, from meteorological numerical model analysis and predictions, from balloon-borne in-situ radiosoundings, as well as from spaceborne infrared radiometers. These different sources of integrated water vapor (IWV) observations have been analyzed and compared to quantify the accuracy and investigate the potential for mitigating IWV-related electromagnetic path delay errors in Interferometric Synthetic Aperture Radar (InSAR) imaging. The results, which include a triple collocation analysis accounting for errors inherently present in every IWV measurements, are valid not only to InSAR but also to any other application involving water vapor sensing. The present analysis concludes that the requirements for mitigating the effects of turbulent water vapor component into InSAR are significantly higher than the accuracy of the instruments analyzed here. Nonetheless, information on the IWV vertical stratification from satellite observations, numerical models, and GPS receivers may provide valuable aid to suppress the long spatial wavelength (>20 km) component of the atmospheric delay, and thus significantly improve the performances of InSAR phase unwrapping techniques.

Download Full-text

The International Soil Moisture Network: serving Earth system science for over a decade

10.5194/hess-2021-2 ◽

2021 ◽

Author(s):

Wouter Dorigo ◽

Irene Himmelbauer ◽

Daniel Aberer ◽

Lukas Schremmer ◽

Ivana Petrakovic ◽

...

Keyword(s):

Quality Control ◽

Soil Moisture ◽

European Space Agency ◽

Data Repository ◽

Reference Database ◽

Data Sets ◽

Scientific Publications ◽

Data Set ◽

Space Agency

Abstract. In 2009, the International Soil Moisture Network (ISMN) was initiated as a community effort, funded by the European Space Agency, to serve as a centralised data hosting facility for globally available in situ soil moisture measurements (Dorigo et al., 2011a, b). The ISMN brings together in situ soil moisture measurements collected and freely shared by a multitude of organisations, harmonizes them in terms of units and sampling rates, applies advanced quality control, and stores them in a database. Users can freely retrieve the data from this database through an online web portal (https://ismn.earth). Meanwhile, the ISMN has evolved into the primary in situ soil moisture reference database worldwide, as evidenced by more than 3000 active users and over 1000 scientific publications referencing the data sets provided by the network. As of December 2020, the ISMN now contains data of 65 networks and 2678 stations located all over the globe, with a time period spanning from 1952 to present.The number of networks and stations covered by the ISMN is still growing and many of the data sets contained in the database continue to be updated. The main scope of this paper is to inform readers about the evolution of the ISMN over the past decade,including a description of network and data set updates and quality control procedures. A comprehensive review of existing literature making use of ISMN data is also provided in order to identify current limitations in functionality and data usage, and to shape priorities for the next decade of operations of this unique community-based data repository.

Download Full-text

The AQUI Soil Moisture Network for Satellite Microwave Remote Sensing Validation in South-Western France

Remote Sensing ◽

10.3390/rs10111839 ◽

2018 ◽

Vol 10 (11) ◽

pp. 1839 ◽

Cited By ~ 5

Author(s):

A. Al-Yaari ◽

S. Dayau ◽

C. Chipeaux ◽

C. Aluome ◽

A. Kruszewski ◽

...

Keyword(s):

Remote Sensing ◽

Soil Moisture ◽

Agricultural Research ◽

Pearson Correlation ◽

European Space Agency ◽

Microwave Remote Sensing ◽

Climate Conditions ◽

Space Agency ◽

Satellite Microwave

Global soil moisture (SM) products are currently available thanks to microwave remote sensing techniques. Validation of these satellite-based SM products over different vegetation and climate conditions is a crucial step. INRA (National Institute of Agricultural Research) has set up the AQUI SM and soil temperature in situ network (composed of three main sites Bouron, Bilos, and Hermitage), over a flat area of dense pine forests, in South-Western France (the Bordeaux–Aquitaine region) to validate the Soil Moisture and Ocean salinity (SMOS) satellite SM products. SMOS was launched in 2009 by the European Space Agency (ESA). The aims of this study are to present the AQUI network and to evaluate the SMOS SM product (in the new SMOS-IC version) along with other microwave SM products such as the active ASCAT (Advanced Scatterometer) and the ESA combined (passive and active) CCI (Climate Change Initiative) SM retrievals. A first comparison, using Pearson correlation, Bias, RMSE (Root Mean Square Error), and Un biased RMSE (ubRMSE) scores, between the 0–5 cm AQUI network and ASCAT, CCI, and SMOS SM products was conducted. In general all the three products were able to reproduce the annual cycle of the AQUI in situ observations. CCI and ASCAT had best and similar correlations (R~0.72) over the Bouron and Bilos sites. All had comparable correlations over the Hermitage sites with overall average values of 0.74, 0.68, and 0.69 for CCI, SMOS-IC, and ASCAT, respectively. Considering anomalies, correlation values decreased for all products with best ability to capture day to day variations obtained by ASCAT. CCI (followed by SMOS-IC) had the best ubRMSE values (mostly < 0.04 m3/m3) over most of the stations. Although the region is highly impacted by radio frequency interferences, SMOS-IC followed correctly the in situ SM dynamics. All the three remotely-sensed SM products (except SMOS-IC over some stations) overestimated the AQUI in situ SM observations. These results demonstrate that the AQUI network is likely to be well-suited for satellite microwave remote sensing evaluations/validations.

Download Full-text

16O/18O ratio in water in the coma of comet 67P/Churyumov-Gerasimenko measured with the Rosetta/ROSINA double-focusing mass spectrometer

Astronomy and Astrophysics ◽

10.1051/0004-6361/201833806 ◽

2019 ◽

Vol 630 ◽

pp. A29 ◽

Cited By ~ 8

Author(s):

Isaac R. H. G. Schroeder I ◽

Kathrin Altwegg ◽

Hans Balsiger ◽

Jean-Jacques Berthelier ◽

Johan De Keyser ◽

...

Keyword(s):

Solar System ◽

Mass Spectrometer ◽

European Space Agency ◽

Space Agency ◽

Close Proximity ◽

Terrestrial Water ◽

Double Focusing ◽

Comet 67P ◽

Almost Continuous

The European Space Agency spacecraft Rosetta accompanied the Jupiter-family comet 67P/Churyumov-Gerasimenko for over 2 yr along its trajectory through the inner solar system. Between 2014 and 2016, it performed almost continuous in situ measurements of the comet’s gaseous atmosphere in close proximity to its nucleus. In this study, the 16O/18O ratio of H2O in the coma of 67P/Churyumov-Gerasimenko, as measured by the ROSINA DFMS mass spectrometer onboard Rosetta, was determined from the ratio of H216O/H218O and 16OH/18OH. The value of 445 ± 35 represents an ~11% enrichment of 18O compared with the terrestrial ratio of 498.7 ± 0.1. This cometary value is consistent with the comet containing primordial water, in accordance with leading self-shielding models. These models predict primordial water to be between 5 and 20% enriched in heavier oxygen isotopes compared to terrestrial water.

Download Full-text

Cross Sensor Simulation of Tomographic SAR Stacks

Remote Sensing ◽

10.3390/rs11182099 ◽

2019 ◽

Vol 11 (18) ◽

pp. 2099 ◽

Cited By ~ 1

Author(s):

Mauro Mariotti d’Alessandro ◽

Stefano Tebaldini

Keyword(s):

European Space Agency ◽

Three Dimensional ◽

Original Data ◽

Central Frequency ◽

Tropical Regions ◽

Space Agency ◽

Simulated System ◽

Good Proxy ◽

The Relationship ◽

Resolution Cell

This paper presents an algorithm for simulating tomographic synthetic aperture radar (SAR) data based on another stack actually gathered by a real acquisition system. Through the procedure here proposed, the simulated system can be evaluated according to its capability to image complex natural media rather than reference point targets. This feature is particularly important whenever the biophysical properties of the target of interest must be preserved and cannot be easily modeled. The system to be simulated may be different from the original one concerning resolution, off-nadir angles, bandwidth and central frequency. The algorithm here proposed handles these differences by properly taking into account the wavenumbers of the target illuminated by the real survey and requested by the simulated one. The complex images constituting the synthetic stack are associated with the effective vertical interferometric wavenumber peculiar of the geometry to be simulated, regardless of the original data. Furthermore, the three-dimensional resolution cell of the simulated tomographic system is consistent with the simulated geometry concerning size and spatial orientation. These two latter features cannot be guaranteed by simply filtering the original stack. The simulator here proposed has been used to simulate the tomographic stack expected from the forthcoming European Space Agency (ESA) BIOMASS mission. The relationship between baseline distribution and 3D focusing capability was explored; special attention has been paid to the robustness of tomographic power at being a good proxy for the above ground biomass in tropical regions.

Download Full-text