scholarly journals Helioseismology from space, the SOHO project

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.

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

1995 ◽  
Vol 10 ◽  
pp. 291-293
Author(s):  
Martin C.E. Huber ◽  
Arne Pedersen ◽  
Claus Fröhlich
Keyword(s):  
Spatial Scales ◽  
Plasma Heating ◽  
European Space Agency ◽  
Three Dimensional ◽  
Plasma Boundary ◽  
Small Scale ◽  
Space Agency ◽  
Terrestrial Magnetosphere ◽  
Surrounding Space

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.

scholarly journals Merged SAGE II, Ozone_cci and OMPS ozone profile dataset and evaluation of ozone trends in the stratosphere

2017 ◽  
Vol 17 (20) ◽  
pp. 12533-12552 ◽  
Author(s):  
Viktoria F. Sofieva ◽  
Erkki Kyrölä ◽  
Marko Laine ◽  
Johanna Tamminen ◽  
Doug Degenstein ◽  
...  
Keyword(s):  
Climate Change ◽  
Stratospheric Ozone ◽  
European Space Agency ◽  
Space Agency ◽  
Ozone Profile ◽  
Ozone Trends ◽  
Stratospheric Cooling ◽  
The Individual ◽  
Good Agreement

Abstract. In this paper, we present a merged dataset of ozone profiles from several satellite instruments: SAGE II on ERBS, GOMOS, SCIAMACHY and MIPAS on Envisat, OSIRIS on Odin, ACE-FTS on SCISAT, and OMPS on Suomi-NPP. The merged dataset is created in the framework of the European Space Agency Climate Change Initiative (Ozone_cci) with the aim of analyzing stratospheric ozone trends. For the merged dataset, we used the latest versions of the original ozone datasets. The datasets from the individual instruments have been extensively validated and intercompared; only those datasets which are in good agreement, and do not exhibit significant drifts with respect to collocated ground-based observations and with respect to each other, are used for merging. The long-term SAGE–CCI–OMPS dataset is created by computation and merging of deseasonalized anomalies from individual instruments. The merged SAGE–CCI–OMPS dataset consists of deseasonalized anomalies of ozone in 10° latitude bands from 90° S to 90° N and from 10 to 50 km in steps of 1 km covering the period from October 1984 to July 2016. This newly created dataset is used for evaluating ozone trends in the stratosphere through multiple linear regression. Negative ozone trends in the upper stratosphere are observed before 1997 and positive trends are found after 1997. The upper stratospheric trends are statistically significant at midlatitudes and indicate ozone recovery, as expected from the decrease of stratospheric halogens that started in the middle of the 1990s and stratospheric cooling.

scholarly journals Merged SAGE II, Ozone_cci and OMPS ozone profiles dataset and evaluation of ozone trends in the stratosphere

2017 ◽  
Author(s):  
Viktoria F. Sofieva ◽  
Erkki Kyrölä ◽  
Marko Laine ◽  
Johanna Tamminen ◽  
Doug Degenstein ◽  
...  
Keyword(s):  
Climate Change ◽  
Linear Regression ◽  
Multiple Linear Regression ◽  
Stratospheric Ozone ◽  
European Space Agency ◽  
Space Agency ◽  
Ozone Trends ◽  
The Individual ◽  
Good Agreement

Abstract. In this paper, we present a merged dataset of ozone profiles from several satellite instruments: SAGE II on ERBS, GOMOS, SCIAMACHY and MIPAS on Envisat, OSIRIS on Odin, ACE-FTS on SCISAT, and OMPS on Suomi-NPP. The merged dataset is created in the framework of European Space Agency Climate Change Initiative (Ozone_cci) with the aim of analyzing stratospheric ozone trends. For the merged dataset, we used the latest versions of the original ozone datasets. The datasets from the individual instruments have been extensively validated and inter-compared; only those datasets, which are in good agreement and do not exhibit significant drifts with respect to collocated ground-based observations and with respect to each other, are used for merging. The long-term SAGE-CCI-OMPS dataset is created by computation and merging of deseasonalized anomalies from individual instruments. The merged SAGE-CCI-OMPS dataset consists of deseasonalized anomalies of ozone in 10° latitude bands from 90° S to 90° N and from 10 to 50 km in steps of 1 km covering the period from October 1984 to July 2016. This newly created dataset is used for evaluating ozone trends in the stratosphere through multiple linear regression. Negative ozone trends in the upper stratosphere are observed before 1997 and positive trends are found after 1997. The upper stratospheric trends are statistically significant at mid-latitudes in the upper stratosphere and indicate ozone recovery, as expected from the decrease of stratospheric halogens that started in the middle of the 1990s.

scholarly journals Long-term Preservation of Earth Observation Data and Knowledge in ESA through CASPAR

2009 ◽  
Vol 4 (3) ◽  
pp. 4-16 ◽  
Author(s):  
Sergio Albani ◽  
David Giaretta
Keyword(s):  
Performing Arts ◽  
Reference Model ◽  
European Space Agency ◽  
Earth Observation ◽  
Observation Data ◽  
Digital Information ◽  
The Earth ◽  
Space Agency ◽  
Long Term Preservation

ESA-ESRIN, the European Space Agency Centre for Earth Observation (EO), is the largest European EO data provider and operates as the reference European centre for EO payload data exploitation. EO Space Missions provide global coverage of the Earth across both space and time generating on a routine continuous basis huge amounts of data (from a variety of sensors) that need to be acquired, processed, elaborated, appraised and archived by dedicated systems. Long-term Preservation of these data and of the ability to discover, access and process them is a fundamental issue and a major challenge at programmatic, technological and operational levels.Moreover these data are essential for scientists needing broad series of data covering long time periods and from many sources. They are used for many types of investigations including ones of international importance such as the study of the Global Change and the Global Monitoring for Environment and Security (GMES) Program. Therefore it is of primary importance not only to guarantee easy accessibility of historical data but also to ensure users are able to understand and use them; in fact data interpretation can be even more complicated given the fact that scientists may not have (or may not have access to) the right knowledge to interpret these data correctly.To satisfy these requirements, the European Space Agency (ESA), in addition to other internal initiatives, is participating in several EU-funded projects such as CASPAR (Cultural, Artistic, and Scientific knowledge for Preservation, Access and Retrieval), which is building a framework to support the end-to-end preservation lifecycle for digital information, based on the OAIS reference model, with a strong focus on the preservation of the knowledge associated with data.In the CASPAR Project ESA plays the role of both user and infrastructure provider for one of the scientific testbeds, putting into effect dedicated scenarios with the aim of validating the CASPAR solutions in the Earth Science domain. The other testbeds are in the domains of Cultural Heritage and of Contemporary Performing Arts; together they provide a severe test of preservation tools and techniques.In the context of the current ESA overall strategies carried out in collaboration with European EO data owners/providers, entities and institutions which have the objective of guaranteeing long-term preservation of EO data and knowledge, this paper will focus on the ESA participation and contribution to the CASPAR Project, describing in detail the implementation of the ESA scientific testbed.

Investigation of the coronal heating through phase relation of solar activity indexes

2020 ◽  
Vol 37 ◽  
Author(s):  
K. J. Li ◽  
J. C. Xu ◽  
Z. Q. Yin ◽  
J. L. Xie ◽  
W. Feng
Keyword(s):  
Solar Wind ◽  
Solar Activity ◽  
Phase Relation ◽  
Large Scale ◽  
Solar Rotation ◽  
Rotation Period ◽  
Magnetic Activity ◽  
Coronal Heating ◽  
Small Scale

Abstract The coronal heating problem is a long-standing perplexing issue. In this study, 13 solar activity indexes are used to investigate their phase relation with the sunspot number (SSN). Only three of them are found to statistically significantly lag the SSN (large-scale magnetic activity) by about one solar rotation period; the three indexes are total solar irradiance (TSI), the modified coronal index, and the solar wind velocity; the former two indexes may represent the long-term variation of energy quantity of the heated photosphere and corona, respectively. The Mount Wilson Sunspot Index (MWSI) and the Magnetic Plage Strength Index (MPSI), which reflect the large- and small-scale magnetic field activities, respectively, are also utilised to investigate their phase relations with the three indexes. The three indexes are found to be much more intimately related to MPSI than to MWSI, and MWSI statistically significantly leads TSI by about one rotation period. The heated corona is found to pulse perfectly in step with the small-scale magnetic activity rather than the large-scale magnetic activity; furthermore, combined with observations, our statistical evidence should thus attribute coronal heating firmly to small-scale magnetic activity phenomena, such as spicules, micro-flares, nano-flares, and others. The photosphere and the corona are synchronously heated, which should seemingly prefer magnetic reconnection heating to wave heating. In the long term, such a coronal heating way is inferred effective. Statistically, it is also small-scale magnetic activity phenomena that produce TSI enhancement. Coronal heating and solar wind acceleration are found to be synchronous, as standard models require.

Towards a cooperation between the arts, space science research and the European Space Agency – Preliminary findings of the ESA Topical Team Arts and Sciences (ETTAS)

2014 ◽  
Vol 105 (1) ◽  
pp. 181-191
Author(s):  
Sarah Jane Pell ◽  
Anna Barbara Imhof ◽  
Christian Waldvogel ◽  
J. Michelle Kotler ◽  
Marko Peljhan
Keyword(s):  
European Space Agency ◽  
Science Research ◽  
Space Science ◽  
Arts And Sciences ◽  
Space Agency ◽  
The Arts

ESA CCI and C3S Soil Moisture: latest product updates and climate assessments

2020 ◽  
Author(s):  
Wouter Dorigo ◽  
Wolfgang Preimesberger ◽  
Adam Pasik ◽  
Alexander Gruber ◽  
Leander Moesinger ◽  
...  
Keyword(s):  
Climate Change ◽  
Soil Moisture ◽  
European Space Agency ◽  
Climate Data ◽  
Change Initiative ◽  
Space Agency ◽  
Data Store ◽  
Climate Data Record ◽  
Level 2

<p>As part of the European Space Agency (ESA) Climate Change Initiative (CCI) a more than 40 year long climate data record (CDR) is produced by systematically combining Level-2 datasets from separate missions. Combining multiple level 2 datasets into a single consistent long-term product combines the advantages of individual missions and allows deriving a harmonised long-term record with optimal spatial and temporal coverage. The current version of ESA CCI Soil Moisture includes a PASSIVE (radiometer-based) dataset covering the period 1978 to 2019, an ACTIVE (scatterometer-based) product covering the period 1991-2019 and a COMBINED product (1978-2019). </p><p>The European Commission’s Copernicus Climate Changes Service (C3S) uses the ESA CCI soil moisture algorithm to produce similar climate data records from near-real-time Level-2 data streams.  These products are continuously extended within 10 days after data acquisition and instantaneously made available through the C3S Climate Data Store. In addition to a daily product, monthly aggregates as well as a dekadal (10-days) products are produced.</p><p>In this presentation we give an overview of the latest developments of the ESA CCI and C3S Soil Moisture datasets, which include the integration of SMAP and various algorithmic updates, and use the datasets to assess the hydrological conditions of 2019 with respect to a 30-year historical baseline.</p><p>The development of the ESA CCI products has been supported by ESA’s Climate Change Initiative for Soil Moisture (Contract No. 4000104814/11/I-NB and 4000112226/14/I-NB). The Copernicus Climate Change Service (C3S) soil moisture product is funded by the Copernicus Climate Change Service implemented by ECMWF through C3S 312b Lot 7 Soil Moisture service.</p>

scholarly journals First observations of magnetic holes deep within the coma of a comet

2018 ◽  
Vol 618 ◽  
pp. A114 ◽  
Author(s):  
F. Plaschke ◽  
T. Karlsson ◽  
C. Götz ◽  
C. Möstl ◽  
I. Richter ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Solar Wind ◽  
Field Strength ◽  
Magnetic Field Strength ◽  
European Space Agency ◽  
Time Frame ◽  
Fluxgate Magnetometer ◽  
Space Agency ◽  
First Time ◽  
Comet 67P

The Rosetta spacecraft of the European Space Agency made ground-breaking observations of comet 67P/Churyumov-Gerasimenko and of its cometary environment. We search for magnetic holes in that environment, i.e., significant depressions in the magnetic field strength, measured by the Rosetta fluxgate Magnetometer (MAG) in April and May 2015. In that time frame of two months, we identified 23 magnetic holes. The cometary activity was intermediate and increasing because Rosetta was on the inbound leg toward the Sun. While in April solar wind protons were still observed by Rosetta near the comet, in May these protons were already mostly replaced by heavy cometary ions. Magnetic holes have frequently been observed in the solar wind. We find, for the first time, that magnetic holes exist in the cometary environment even when solar wind protons are almost absent. Some of the properties of the magnetic holes are comparable to those of solar wind holes; they are associated with density enhancements, sometimes associated with co-located current sheets and fast solar wind streams, and are of similar scales. However, particularly in May, the magnetic holes near the comet appear to be more processed, featuring shifted density enhancements and, sometimes, bipolar signatures in magnetic field strength rather than simple depressions. The magnetic holes are of global size with respect to the coma. However, at the comet, they are compressed owing to magnetic field pile-up and draping so that they change in shape. There, the magnetic holes become of comparable size to heavy cometary ion gyroradii, potentially enabling kinetic interactions.

SOHO Science Opportunities

1994 ◽  
Vol 144 ◽  
pp. 609-613
Author(s):  
B. Fleck ◽  
V. Domingo ◽  
A. I. Poland
Keyword(s):  
Solar Wind ◽  
Joint Venture ◽  
Space Science ◽  
Solar Interior ◽  
Physical Processes ◽  
Heliospheric Observatory ◽  
Structure And Dynamics ◽  
Science Programme ◽  
Insight Into

AbstractThe space-based Solar and Heliospheric Observatory (SOHO) is a joint venture of ESA and NASA within the frame of the Solar Terrestrial Science Programme (STSP), the first ”Cornerstone“ of ESA’s long-term programme ”Space Science — Horizon 2000“. The principal scientific objectives of the SOHO mission are: a) a better understanding of the structure and dynamics of the solar interior using techniques of helioseismology, and b) a better insight into the physical processes that form and heat the Sun’s corona, maintain it and give rise to its acceleration into the solar wind. To achieve these goals, SOHO carries a payload consisting of 12 sets of complementary instruments which are briefly described here.

scholarly journals Radiometric accuracy and stability of sentinel-1A determined using point targets

2018 ◽  
Vol 10 (5-6) ◽  
pp. 538-546 ◽  
Author(s):  
Kersten Schmidt ◽  
Núria Tous Ramon ◽  
Marco Schwerdt
Keyword(s):  
European Space Agency ◽  
High Elevation ◽  
Calibration Factor ◽  
Synthetic Aperture ◽  
Absolute Calibration ◽  
Long Term Stability ◽  
Space Agency ◽  
Imaging Mode ◽  
German Aerospace

ABSTRACTSentinel-1A is a space-borne synthetic aperture radar (SAR) system developed in the frame of the Copernicus Program. The German Aerospace Center supported the radiometric and polarimetric calibration of Sentinel-1A by the analysis of point target responses of several acquisitions considering different modes, beams, and polarization channels. An elevation dependent bias, which had not been properly predicted by the used antenna model, was found for all investigated modes. Offsets of up to 2 dB were determined during the SAR instrument calibration phase, in particular, for low and high elevation angles. Therefore, in order to correct these elevation biases, a radiometric refinement was carried out by European Space Agency in November 2015. After that, Sentinel-1A radiometric accuracy and long-term stability were analyzed over a period of 1.5 years. For this period, the absolute calibration factor and the channel imbalance were determined for the main imaging mode. Moreover, a slight drift of the derived calibration factor was observed starting from July 2016. At the same time an anomaly was detected in the front-end affecting several transmit and receive modules in one tile. The radiometric behavior of Sentinel-1A should therefore be monitored for a longer period of time, especially to detect potential degradation effects of the SAR instrument.

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