scholarly journals Ground-based visible spectroscopy of asteroids to support the development of an unsupervised Gaia asteroid taxonomy

2020 ◽  
Vol 642 ◽  
pp. A80
Author(s):  
A. Cellino ◽  
Ph. Bendjoya ◽  
M. Delbo’ ◽  
L. Galluccio ◽  
J. Gayon-Markt ◽  
...  
Keyword(s):  
Spectral Resolution ◽  
Spectroscopic Data ◽  
European Space Agency ◽  
Taxonomic Classification ◽  
Data Sets ◽  
Simulated Population ◽  
Low Resolution ◽  
Single Class ◽  
Space Agency ◽  
Rare Classes

Context. The Gaia mission of the European Space Agency is measuring reflectance spectra of a number to the order of 105 small Solar System objects. A first sample will be published in the Gaia Data Release scheduled for 2021. Aims. The aim of our work was to test the procedure developed to obtain taxonomic classifications for asteroids based only on Gaia spectroscopic data. Methods. We used asteroid spectra obtained using the DOLORES (Device Optimised for the LOw RESolution) instrument, a low-resolution spectrograph and camera installed at the Nasmyth B focus of the Telescopio Nazionale Galileo. Because these spectra have a higher spectral resolution than that typical of the Gaia spectra, we resampled them to more closely match the expected Gaia spectral resolution. We then developed a cloning algorithm to build a database of asteroid spectra belonging to a variety of taxonomic classes, starting from a set of 33 prototypes chosen from the 50 asteroids in our observing campaign. We used them to generate a simulated population of 10 000 representative asteroid spectra and employed them as the input to the algorithm for taxonomic classification developed to analyze Gaia asteroid spectra. Results. Using the simulated population of 10 000 representative asteroid spectra in the algorithm to be used to produce the Gaia asteroid taxonomy at the end of the mission, we found 12 distinct taxonomic classes. Two of them, with 53% of the sample, are dominant. At the other extreme are three classes each with <1% of the sample, and these consist of the previously known rare classes A, D/Ld, and V; 99.1% of the simulated population fall into a single class. Conclusions. We demonstrated the robustness of our algorithm for taxonomic classification by using a sample of simulated asteroid spectra fully representative of what is expected to be in the Gaia spectroscopic data catalogue for asteroids. Increasingly larger data sets will become available as soon as they are published in the future Gaia data releases, with the next one coming in 2021. This will be exploited to develop a correspondingly improved taxonomy, likely with minor tweaks to the algorithm described here, as suggested by the results of this preliminary analysis.

scholarly journals Six years of total ozone column measurements from SCIAMACHY nadir observations

2009 ◽  
Vol 2 (1) ◽  
pp. 87-98 ◽  
Author(s):  
C. Lerot ◽  
M. Van Roozendael ◽  
J. van Geffen ◽  
J. van Gent ◽  
C. Fayt ◽  
...  
Keyword(s):  
Cross Sections ◽  
Total Ozone ◽  
Large Scale ◽  
European Space Agency ◽  
Data Sets ◽  
Data Set ◽  
Ozone Data ◽  
Space Agency ◽  
German Aerospace ◽  
The Impact

Abstract. Total O3 columns have been retrieved from six years of SCIAMACHY nadir UV radiance measurements using SDOAS, an adaptation of the GDOAS algorithm previously developed at BIRA-IASB for the GOME instrument. GDOAS and SDOAS have been implemented by the German Aerospace Center (DLR) in the version 4 of the GOME Data Processor (GDP) and in version 3 of the SCIAMACHY Ground Processor (SGP), respectively. The processors are being run at the DLR processing centre on behalf of the European Space Agency (ESA). We first focus on the description of the SDOAS algorithm with particular attention to the impact of uncertainties on the reference O3 absorption cross-sections. Second, the resulting SCIAMACHY total ozone data set is globally evaluated through large-scale comparisons with results from GOME and OMI as well as with ground-based correlative measurements. The various total ozone data sets are found to agree within 2% on average. However, a negative trend of 0.2–0.4%/year has been identified in the SCIAMACHY O3 columns; this probably originates from instrumental degradation effects that have not yet been fully characterized.

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

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.

scholarly journals The Use of SAR Satellite Imagery to Measure Active Layer Moisture Contents in Arctic Alaska

1996 ◽  
Vol 27 (1-2) ◽  
pp. 25-38 ◽  
Author(s):  
D. L. Kane ◽  
L. D. Hinzman ◽  
Haofang Yu ◽  
D. J. Goering
Keyword(s):  
Surface Soil ◽  
European Space Agency ◽  
Data Sets ◽  
Near Surface ◽  
Moisture Contents ◽  
Space Agency ◽  
Arctic Alaska ◽  
Pixel Value ◽  
Sar Imagery ◽  
Measured Moisture Content

Synthetic aperture radar (SAR) has the potential for measuring near surface soil moisture contents for very large areas. The polar orbiting European Remote Sensing satellite (ERS-1) of the European Space Agency (ESA) has onboard an active C-band SAR sensor. We have analyzed SAR imagery over a small research watershed, Imnavait Creek, located in the northern foothills of the Brooks Range in Alaska, U.S.A. This watershed is treeless and completely underlain with permafrost. After geometrically and radiometrically correcting each pixel (25 m by 25 m) in the image, corrected pixel values were correlated with corresponding field moisture contents measured along transects in the watershed for two passes of the satellite. Coefficients of determination, r2, between the corrected pixel value and measured moisture content were 0.49 on June 12, 1993 and 0.53 on August 2, 1993; with the data sets combined the value was 0.50.

scholarly journals Tropospheric column amount of ozone retrieved from SCIAMACHY limb-nadir-matching observations

2013 ◽  
Vol 6 (4) ◽  
pp. 7811-7865 ◽  
Author(s):  
F. Ebojie ◽  
C. von Savigny ◽  
A. Ladstätter-Weißenmayer ◽  
A. Rozanov ◽  
M. Weber ◽  
...  
Keyword(s):  
Atmospheric Chemistry ◽  
Tropospheric Ozone ◽  
Weighting Function ◽  
European Space Agency ◽  
Optical Absorption Spectroscopy ◽  
Data Sets ◽  
Ozone Monitoring Instrument ◽  
Space Agency ◽  
Tropospheric O3 ◽  
Scanning Imaging

Abstract. Tropospheric ozone, O3, has two sources: transport from the stratosphere and photochemical production in the troposphere. It plays important roles in atmospheric chemistry and climate change. In this manuscript we describe the retrieval of tropospheric O3 columns from limb-nadir matching (LNM) observations of the SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY (SCIAMACHY) instrument, which flies as part of the payload onboard the European Space Agency (ESA) satellite Envisat. This retrieval technique is a residual approach that utilizes the subtraction of the stratospheric O3 columns, derived from the limb observations, from the total O3 columns, derived from the nadir observations. The technique requires accurate knowledge of the stratospheric O3 columns, the total O3 columns, tropopause height, and their associated errors. The stratospheric O3 columns were determined from the stratospheric O3 profile retrieved in the Hartley and Chappius bands, based on SCIAMACHY limb scattering measurements. The total O3 columns were also derived from SCIAMACHY measurements, in the nadir viewing mode using the Weighting Function Differential Optical Absorption Spectroscopy (WFDOAS) technique in the Huggins band. Comparisons of the tropospheric O3 columns from SCIAMACHY and collocated measurements from ozonesondes, in both hemispheres between January 2003 and December 2011 show agreement to within 2–5 DU (1 DU = 2.69 × 1016 molecules cm−2). Comparison of tropospheric O3 from SCIAMACHY with the results from ozonesondes, the Tropospheric Emission Spectrometer (TES), and the LNM method combining Ozone Monitoring Instrument (OMI) and Microwave Limb Sounder (MLS) data (hereinafter referred to as OMI/MLS), have been investigated. We find that all four retrieved data sets show agreement within the error bars and exhibit strong seasonal variation, which differs in amplitude. The spatial distribution of tropospheric ozone observed shows pollution plumes related to the release of precursors at the different seasons in both hemispheres.

scholarly journals Effects of heatwaves on lake composition derived from satellite observations

2021 ◽  
Author(s):  
Marloes Penning de Vries ◽  
Suhyb Salama ◽  
Chris Mannaerts ◽  
Daphne van der Wal
Keyword(s):  
Climate Change ◽  
Water Quality ◽  
European Space Agency ◽  
Climate Change Impacts ◽  
Aquatic Organisms ◽  
Data Sets ◽  
Space Agency ◽  
Lake Temperature ◽  
Suitable Habitats ◽  
Projected Changes

&lt;p&gt;As a consequence of the ever-increasing global temperature, not only the air, and surface, but also lakes are warming up. This is expressed by steadily increasing base temperatures, but also in increases in the frequency and intensity of lake heatwaves. Land-based organisms may adapt to a changing climate by migrating to more suitable habitats, but this is usually not an option for lake-dwellers. Because many livelihoods depend on the ecosystem services of lakes, understanding the effects of heatwaves on lake composition form &amp;#160;an important input for the assessment of climate change impacts and design of adaptation strategies.&lt;/p&gt;&lt;p&gt;Using satellite data of lake temperature and water quality observations, we here investigate the effects of heatwaves on lake composition by studying the relationship between heatwaves and water quality variables of temperature, chlorophyll-a , colored dissolved organic matter, and suspended particulate matter . The latter can be used to infer effects of heat stress on health and populations of phyto- and zooplankton communities and higher aquatic organisms. Satellite-based data sets provided by the Climate Change Initiative of the European Space Agency, &amp;#160;CCI-Lakes (https://climate.esa.int/en/projects/lakes/) are&amp;#160; used in conjunction with the 2SeaColor model to determine depth-dependent attenuation coefficients and water quality variables.These data are complemented with and compared to data from Copernicus Global Land Services (https://land.copernicus.eu/global/products/).&amp;#160;&lt;/p&gt;&lt;p&gt;The co-occurrence of heatwaves and changes in lake composition is investigated using statistical tools, and the causality is examined by comparison with biophysical models. The results from this study are discussed in light of previously published projected changes in heatwave frequency and intensity.&lt;/p&gt;

scholarly journals First validation of Aeolus wind observations by airborne Doppler Wind Lidar measurements

2020 ◽  
Author(s):  
Benjamin Witschas ◽  
Christian Lemmerz ◽  
Alexander Geiß ◽  
Oliver Lux ◽  
Uwe Marksteiner ◽  
...  
Keyword(s):  
Early Stage ◽  
European Space Agency ◽  
Global Scale ◽  
Data Sets ◽  
Random Errors ◽  
Space Agency ◽  
Lidar Measurements ◽  
Wind Lidar ◽  
German Aerospace ◽  
First Time

Abstract. Soon after the launch of Aeolus on 22 August 2018, the first ever wind lidar in space developed by the European Space Agency (ESA) has been providing profiles of the component of the wind vector along the instrument's line-of-sight (LOS) on a global scale. In order to validate the quality of Aeolus wind observations, the German Aerospace Center (Deutsches Zentrum für Luft- und Raumfahrt e.V., DLR) recently performed two airborne campaigns over Central Europe deploying two different Doppler wind lidars (DWL) on-board the DLR Falcon aircraft. The first campaign – WindVal III – was conducted from 5 November 2018 until 5 December 2018 and thus, still within the commissioning phase of the Aeolus mission. The second campaign – AVATARE (Aeolus Validation Through Airborne Lidars in Europe) – was performed from 6 May 2019 until 6 June 2019. Both campaigns were flown out of the DLR site in Oberpfaffenhofen, Germany. All together, 10 satellite underflights with 19 flight legs covering more than 7500 km of Aeolus swaths were performed and used to validate the early stage wind data product of Aeolus by means of collocated airborne wind lidar observations for the first time. For both campaign data sets, the statistical comparison of Aeolus data and the data of the reference lidar (2-µm DWL) on-board the Falcon aircraft shows enhanced systematic and random errors compared with the bias and precision requirements defined for Aeolus. In particular, the systematic errors are determined to be 2.1 m/s (Rayleigh) and 2.3 m/s (Mie) for WindVal III and −4.6 m/s (Rayleigh) and −0.2 m/s (Mie) for AVATARE. The corresponding random errors are determined to be 4.0 m/s (Rayleigh) and 2.2 m/s (Mie) for WindVal III, and 4.4 m/s (Rayleigh) and 2.2 m/s (Mie) for AVATARE. Potential reasons for those errors are analyzed and discussed.

scholarly journals Six years of total ozone column measurements from SCIAMACHY nadir observations

2008 ◽  
Vol 1 (1) ◽  
pp. 249-279
Author(s):  
C. Lerot ◽  
M. Van Roozendael ◽  
J. van Geffen ◽  
J. van Gent ◽  
C. Fayt ◽  
...  
Keyword(s):  
Cross Sections ◽  
Total Ozone ◽  
Large Scale ◽  
European Space Agency ◽  
Data Sets ◽  
Data Set ◽  
Ozone Data ◽  
Space Agency ◽  
German Aerospace ◽  
The Impact

Abstract. Total O3 columns have been retrieved from six years of SCIAMACHY nadir UV radiance measurements using SDOAS, an adaptation of the GDOAS algorithm previously developed at BIRA-IASB for the GOME instrument. GDOAS and SDOAS have been implemented by the German Aerospace Center (DLR) in the version 4 of the GOME Data Processor (GDP) and in version 3 of the SCIAMACHY Ground Processor (SGP), respectively. The processors are being run at the DLR processing centre on behalf of the European Space Agency (ESA). We first focus on the description of the SDOAS algorithm with particular attention to the impact of uncertainties on the reference O3 absorption cross-sections. Second, the resulting SCIAMACHY total ozone data set is globally evaluated through large-scale comparisons with results from GOME and OMI as well as with ground-based correlative measurements. The various total ozone data sets are found to agree within 2% on average. However, a negative trend of 0.2–0.4%/year has been identified in the SCIAMACHY O3 columns; this probably originates from instrumental degradation effects that have not yet been fully characterized.

ESA’s Planetary Science Archive, updates since last year!

2020 ◽  
Author(s):  
Sébastien Besse ◽  
Isa Barbarisi ◽  
Guido de Marchi ◽  
Bruno Merin ◽  
Javier Arenas ◽  
...  
Keyword(s):  
Solar System ◽  
Geographical Information Systems ◽  
Scientific Community ◽  
European Space Agency ◽  
Planetary Science ◽  
Scientific Data ◽  
Geographical Information ◽  
Data Sets ◽  
Space Agency ◽  
Search Data

&lt;p&gt;&lt;strong&gt;Abstract&lt;/strong&gt;&lt;/p&gt; &lt;p&gt;With new missions being selected, missions moving to post-operations, and missions starting their journey to various targets in the Solar System, the European Space Agency&amp;#8217;s Planetary Science Archive [1] (http://psa.esa.int) (PSA) is in constant evolution to support the needs of the projects and of the scientific community.&lt;/p&gt; &lt;p&gt;&lt;strong&gt;What happened since last year?&lt;/strong&gt;&lt;/p&gt; &lt;p&gt;The past year has been good for the European Space Agency (ESA) Solar System missions and the PSA, with the successful flyby of Earth by the BepiColombo mission to Mercury. The ExoMars 2016 mission is performing nominally and is quickly delivering numerous scientific observations. As is common for ESA missions, access to the data is protected and reserved to members of the science team for the first months of the mission. Once the products are ready to go public, the PSA performs a scientific peer-review to ensure that the products to be made public are of excellent quality for all future users.&lt;/p&gt; &lt;p&gt;During the first half of 2020, the PSA has successfully peer-reviewed the CaSSIS and NOMAD observations. Those products are now being made public on a systematic basis once the proprietary period elapses (generally between 6 and 12 months).&lt;/p&gt; &lt;p&gt;Early in 2020, filters to search data with geometrical values (i.e., longitude, phase angle, slant distance, etc.) were enabled. For now this service works for Mars Express and Rosetta, but will be soon extended to other missions.&lt;/p&gt; &lt;p&gt;One of the main new services provided to the scientific community in 2020 is the Guest Storage Facility (GSF), which allows users to archive derived products. Products such as geological maps, Digital Terrains Models, new calibrated files, and others can be stored in the GSF in the format most used by the users. Contact us to preserve your science!&lt;/p&gt; &lt;p&gt;Finally, by the end of 2020 users of the PSA will have access to new services based on Geographical Information Systems.&lt;/p&gt; &lt;p&gt;&lt;strong&gt;You can contribute to the PSA!&lt;/strong&gt;&lt;/p&gt; &lt;p&gt;At the PSA we constantly interact with our users to ensure that our services are in line with the expectations and needs of the community. We encourage feedback from community scientists through:&lt;/p&gt; &lt;ul&gt; &lt;li&gt;PSA Users Group: A group of scientific experts advising the PSA on strategic development;&lt;/li&gt; &lt;li&gt;Direct interactions: Scientists from the PSA are available and eager to receive your comments and suggestions;&lt;/li&gt; &lt;li&gt;ESA missions: If you are part of a mission archiving its data at the PSA, tell us how your data should best be searched and used.&lt;/li&gt; &lt;/ul&gt; &lt;p&gt;&lt;strong&gt;Acknowledgement&lt;/strong&gt;&lt;/p&gt; &lt;p&gt;The authors are very grateful to all the people who have contributed over the last 17 years to ESA's Planetary Science Archive. We are also thankful to ESA&amp;#8217;s teams who are operating the missions and to the instrument science teams who are generating and delivering scientific calibrated products to the archive.&lt;/p&gt; &lt;p&gt;&lt;strong&gt;References&lt;/strong&gt;&lt;/p&gt; &lt;p&gt;[1] Besse, S. et al. (2017) Planetary and Space Science, 10.1016/j.pss.2017.07.013, ESA's Planetary Science Archive: Preserve and present reliable scientific data sets.&lt;/p&gt;

scholarly journals The Herschel Point Source Catalogue

2015 ◽  
Vol 11 (S315) ◽  
Author(s):  
G. Marton ◽  
B. Schulz ◽  
B. Altieri ◽  
L. Calzoletti ◽  
Cs. Kiss ◽  
...  
Keyword(s):  
Point Source ◽  
Broad Band ◽  
European Space Agency ◽  
Far Infrared ◽  
Data Sets ◽  
Space Observatory ◽  
Space Agency ◽  
Photometric Observations ◽  
Parallel Mode ◽  
Source Extraction

AbstractThe Herschel Space Observatory was the fourth cornerstone mission in the European Space Agency (ESA) science programme with excellent broad band imaging capabilities in the sub-mm and far-infrared part of the spectrum. Although the spacecraft finished its observations in 2013, it left a large legacy dataset that is far from having been fully scrutinised and still has a large potential for new scientific discoveries. This is specifically true for the photometric observations of the PACS and SPIRE instruments. Some source catalogues have already been produced by individual observing programs, but there are many observations that risk to remain unexplored. To maximise the science return of the SPIRE and PACS data sets, we are in the process of building the Herschel Point Source Catalogue (HPSC) from all primary and parallel mode observations. Our homogeneous source extraction enables a systematic and unbiased comparison of sensitivity across the different Herschel fields that single programs will generally not be able to provide. The catalogue will be made available online through archives like the Herschel Science Archive (HSA), the Infrared Science Archive (IRSA), and the Strasbourg Astronomical Data Center (CDS).

Estimating Relative and Absolute Sea Level Rise at Ny-Ålesundwith satellite altimetry and in-situ observations

2021 ◽  
Author(s):  
Stefano Vignudelli ◽  
Francesco De Biasio
Keyword(s):  
Climate Change ◽  
Sea Level Rise ◽  
Sea Level ◽  
Satellite Altimetry ◽  
Adriatic Sea ◽  
Tide Gauge ◽  
European Space Agency ◽  
Data Sets ◽  
Space Agency ◽  
Along Track

&lt;p&gt;Consistent and long-term satellite-based data-sets to study climate-scale variations of sea level globally and in the coastal zone are available nowadays. Two altimetry data-sets were recently produced: the first one is generated by the European Space Agency&amp;#8217;s (ESA) Sea Level Climate Change Initiative (SL_CCI) over a grid of 0.25 x 0.25 degrees, merging and homogenizing the various available satellite altimetry missions. The second one is a climate-oriented altimeter sea level product that started in the framework of the European Copernicus Climate Change Service (C3S), and is now released as daily-means over a grid of 0.25 x 0.25 degrees, covering the global ocean since 1993 to present. Both reach in the Arctic the latitude of 81.5 N degrees. Therefore, these new altimetry products cover the coastal area surrounding Ny-&amp;#197;lesund (Svalbard Islands, Norway), where a tide gauge station is active since 1976. Near the Svalbard coasts also the along track surface elevations of the CryoSat-2 mission are made available through the European Space Agency&amp;#8217;s Grid Processing on Demand (G-POD) for Earth Observation Applications facility.&lt;/p&gt;&lt;p&gt;In this study, we compare sea level measurements from the Ny-&amp;#197;lesund tide gauge with the climate-oriented altimeter sea level gridded products (SL_CCI and C3S) and with the along track data from the only CryoSat-2 mission. This study has three objectives: 1) to assess the performances of the gridded data moving from offshore to near coasts; 2) to explore how the synergy with along track high resolution CryoSat-2 data might help to detail the sea ice impact on the observation of relative and absolute sea level rise around Svalbard; 3) to verify if the differences between satellite altimetry and tide gauges can be used as a proxy of vertical ground movement in the study area by adopting the approaches elaborated in Vignudelli et al. [2018] and De Biasio et al. [2020] that can be validated with ground vertical displacements estimated using Global Positioning System (GPS) data from the stations close to Ny-&amp;#197;lesund.&lt;/p&gt;&lt;p&gt;&amp;#160;&lt;/p&gt;&lt;p&gt;REFERENCES&lt;/p&gt;&lt;p&gt;Vignudelli, S., De Biasio, F., Scozzari, A. Zecchetto, S., and Papa, A. (2019): Sea Level Trends and Variability in the Adriatic Sea and Around Venice, Proceedings of the International Review Workshop on Satellite Altimetry Cal/Val Activities and Applications, 23-26 April 2018, Chania, Crete, Greece. DOI:10.1007/1345_2018_51&lt;/p&gt;&lt;p&gt;De Biasio, F.; Baldin, G.; Vignudelli, S. Revisiting Vertical Land Motion and Sea Level Trends in the Northeastern Adriatic Sea Using Satellite Altimetry and Tide Gauge Data. J. Mar. Sci. Eng. 2020, 8, 949. DOI:10.3390/jmse8110949&lt;/p&gt;

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