Evaluation of EarthCARE Cloud Profiling Radar Doppler Velocity Measurements in Particle Sedimentation Regimes

Abstract The joint European Space Agency–Japan Aerospace Exploration Agency (ESA–JAXA) Earth Clouds, Aerosols and Radiation Explorer (EarthCARE) mission is scheduled for launch in 2016 and features the first atmospheric Cloud Profiling Radar (CPR) with Doppler capability in space. Here, the uncertainty of the CPR Doppler velocity measurements in cirrus clouds and large-scale precipitation areas is discussed. These regimes are characterized by weak vertical motion and relatively horizontally homogeneous conditions and thus represent optimum conditions for acquiring high-quality CPR Doppler measurements. A large dataset of radar reflectivity observations from ground-based radars is used to examine the homogeneity of the cloud fields at the horizontal scales of interest. In addition, a CPR instrument model that uses as input ground-based radar observations and outputs simulations of CPR Doppler measurements is described. The simulator accurately accounts for the beam geometry, nonuniform beam-filling, and signal integration effects, and it is applied to representative cases of cirrus cloud and stratiform precipitation. The simulated CPR Doppler velocities are compared against those derived from the ground-based radars. The unfolding of the CPR Doppler velocity is achieved using simple conditional rules and a smoothness requirement for the CPR Doppler measurements. The application of nonuniform beam-filling Doppler velocity bias-correction algorithms is found necessary even under these optimum conditions to reduce the CPR Doppler biases. Finally, the analysis indicates that a minimum along-track integration of 5000 m is needed to reduce the uncertainty in the CPR Doppler measurements to below 0.5 m s−1 and thus enable the detection of the melting layer and the characterization of the rain- and ice-layer Doppler velocities.

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Quantifying Horizontal and Vertical Movements in Ho Chi Minh City by Sentinel-1 Radar Interferometry

10.20944/preprints202012.0382.v1 ◽

2020 ◽

Author(s):

Dinh Ho Tong Minh ◽

Yen-Nhi NGO ◽

Thu Trang Lê ◽

Trung Chon Le ◽

Hong Son Bui ◽

...

Keyword(s):

Time Series ◽

Large Scale ◽

European Space Agency ◽

Ground Subsidence ◽

Ho Chi Minh City ◽

Vertical Movements ◽

Space Agency ◽

Permanent Scatterers ◽

The City ◽

East West

Ho Chi Minh City (HCMC), the most populous city and the economic center of Viet Nam, has faced ground subsidence in recent decades. This work aims at providing an unprecedented spatial extent coverage of the subsidence in HCMC in both horizontal and vertical components using Interferometric Synthetic Aperture Radar (InSAR) time series. For this purpose, an advanced InSAR technique PSDS (Permanent Scatterers and Distributed Scatterers) was applied to two big European Space Agency (ESA) Sentinel-1 datasets composed of 96 ascending and 202 descending images, acquired from 2014 to 2020 over HCMC area. A time series of 33 Cosmos SkyMED images was also used for comparison purpose. The combination of ascending and descending satellite passes allows the decomposition of the light of sight velocities into horizontal East-west and vertical components. By taking into account the presence of the horizontal East-west movement, our finding indicates that the precision of the decomposed vertical velocity can be improved up to 3 mm/year for Sentinel-1 data. The obtained results revealed that subsidence is most severe in areas along the Sai Gon river in the northwest-southeast axis and the southwest of the city with the maximum value up to 80 mm/year, consistent with findings in the literature. The magnitude of horizontal East-West velocities is relatively small and a large-scale westward motion can be observed in the northwest of the city at a rate of 2-5 mm/year. Together, these results reinforced the remarkable suitability of ESA's Sentinel-1 SAR for subsidence applications even for non-Europe countries such as Vietnam and Southeast Asia.

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Six years of total ozone column measurements from SCIAMACHY nadir observations

Atmospheric Measurement Techniques ◽

10.5194/amt-2-87-2009 ◽

2009 ◽

Vol 2 (1) ◽

pp. 87-98 ◽

Cited By ~ 39

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.

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Dayside Magnetopause Reconnection and Flux Transfer Events: BepiColombo Earth-Flyby

10.5194/egusphere-egu21-3424 ◽

2021 ◽

Author(s):

Wei-Jie Sun ◽

James Slavin ◽

Rumi Nakamura ◽

Daniel Heyner ◽

Johannes Mieth

Keyword(s):

Magnetic Field ◽

Large Scale ◽

European Space Agency ◽

Flux Rope ◽

Transfer Event ◽

Flux Transfer Events ◽

Space Agency ◽

Flux Ropes ◽

Flux Transfer ◽

Magnetospheric Multiscale Mission

BepiColombo is a joint mission of the European Space Agency (ESA) and the Japan Aerospace Exploration Agency (JAXA) to the planet Mercury. The BepiColombo mission consists of two spacecraft, which are the Mercury Planetary Orbiter (MPO) and Mercury Magnetospheric Orbiter (Mio). The mission made its first planetary flyby, which is the only Earth flyby, on 10 April 2020, during which several instruments collected measurements. In this study, we analyze MPO magnetometer (MAG) observations of Flux Transfer Events (FTEs) in the magnetosheath and the structure of the subsolar magnetopause near the &#160;flow stagnation point. The magnetosheath plasma beta was high with a value of ~ 8 and the interplanetary magnetic field (IMF) was southward with a clock angle that decreased from ~ 100 degrees to ~ 150 degrees. &#160;As the draped IMF became increasingly southward several of the flux transfer event (FTE)-type flux ropes were observed. These FTEs traveled southward indicating that the magnetopause X-line was located northward of the spacecraft, which is consistent with a dawnward tilt of the IMF. Most of the FTE-type flux ropes were in ion-scale, <10 s duration, suggesting that they were newly formed. Only one large-scale FTE-type flux rope, ~ 20 s, was observed. It was made up of two successive bipolar signatures in the normal magnetic field component, which is evidence of coalescence at a secondary reconnection site. Further analysis demonstrated that the dimensionless reconnection rate of the re-reconnection associated with the coalescence site was ~ 0.14. While this investigation was limited to the MPO MAG observations, it strongly supports a key feature of dayside reconnection discovered in the Magnetospheric Multiscale mission, the growth of FTE-type flux ropes through coalescence at secondary reconnection sites.

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Unveiling the faint ultraviolet Universe

Experimental Astronomy ◽

10.1007/s10686-021-09726-8 ◽

2021 ◽

Author(s):

A. Zanella ◽

C. Zanoni ◽

F. Arrigoni-Battaia ◽

A. Rubin ◽

A. F. Pala ◽

...

Keyword(s):

Globular Clusters ◽

Large Scale ◽

European Space Agency ◽

Large Scale Structures ◽

Space Agency ◽

James Webb Space Telescope ◽

Ram Pressure ◽

Infrared Wavelengths ◽

Scale Structures ◽

Integral Field Spectrograph

AbstractWith this paper we participate to the call for ideas issued by the European Space Agency to define the Science Program and plan for space missions from 2035 to 2050. In particular we present five science cases where major advancements can be achieved thanks to space-based spectroscopic observations at ultraviolet (UV) wavelengths. We discuss the possibility to (1) unveil the large-scale structures and cosmic web in emission at redshift $\lesssim 1.7$ ≲ 1.7 ; (2) study the exchange of baryons between galaxies and their surroundings to understand the contribution of the circumgalactic gas to the evolution and angular-momentum build-up of galaxies; (3) constrain the efficiency of ram-pressure stripping in removing gas from galaxies and its role in quenching star formation; (4) characterize the progenitor population of core-collapse supernovae to reveal the explosion mechanisms of stars; (5) target accreting white dwarfs in globular clusters to determine their evolution and fate. These science themes can be addressed thanks to UV (wavelength range $\lambda \sim 90 - 350$ λ ∼ 90 − 350 nm) observations carried out with a panoramic integral field spectrograph (field of view $\sim \!1 \times 1$ ∼ 1 × 1 arcmin2), and medium spectral (R = 4000) and spatial ($\sim \!1^{\prime \prime } - 3^{\prime \prime }$ ∼ 1 ′ ′ − 3 ′ ′ ) resolution. Such a UV-optimized instrument will be unique in the coming years, when most of the new large facilities such as the Extremely Large Telescope and the James Webb Space Telescope are optimized for infrared wavelengths.

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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.

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Detection capabilities of the Athena X-IFU for the warm-hot intergalactic medium using gamma-ray burst X-ray afterglows

Astronomy and Astrophysics ◽

10.1051/0004-6361/202037775 ◽

2020 ◽

Vol 642 ◽

pp. A24

Author(s):

Sarah Walsh ◽

Sheila McBreen ◽

Antonio Martin-Carrillo ◽

Thomas Dauser ◽

Nastasha Wijers ◽

...

Keyword(s):

Large Scale ◽

Intergalactic Medium ◽

Gamma Ray ◽

Statistical Significance ◽

European Space Agency ◽

Gamma Ray Burst ◽

X Ray ◽

Baryonic Density ◽

Space Agency ◽

High Statistical Significance

At low redshifts, the observed baryonic density falls far short of the total number of baryons predicted. Cosmological simulations suggest that these baryons reside in filamentary gas structures, known as the warm-hot intergalactic medium (WHIM). As a result of the high temperatures of these filaments, the matter is highly ionised such that it absorbs and emits far-UV and soft X-ray photons. Athena, the proposed European Space Agency X-ray observatory, aims to detect the “missing” baryons in the WHIM up to redshifts of z = 1 through absorption in active galactic nuclei and gamma-ray burst (GRB) afterglow spectra, allowing for the study of the evolution of these large-scale structures of the Universe. This work simulates WHIM filaments in the spectra of GRB X-ray afterglows with Athena using the SImulation of X-ray TElescopes framework. We investigate the feasibility of their detection with the X-IFU instrument, through O VII (E = 573 eV) and O VIII (E = 674 eV) absorption features, for a range of equivalent widths imprinted onto GRB afterglow spectra of observed starting fluxes ranging between 10−12 and 10−10 erg cm−2 s−1, in the 0.3−10 keV energy band. The analyses of X-IFU spectra by blind line search show that Athena will be able to detect O VII−O VIII absorption pairs with EWO VII > 0.13 eV and EWO VIII > 0.09 eV for afterglows with F > 2 × 10−11 erg cm−2 s−1. This allows for the detection of ≈ 45−137 O VII−O VIII absorbers during the four-year mission lifetime. The work shows that to obtain an O VII−O VIII detection of high statistical significance, the local hydrogen column density should be limited at NH < 8 × 1020 cm−2.

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Study of Galactic Cosmic-Ray Flux Modulation by Interplanetary Plasma Structures for the Evaluation of Space Instrument Performance and Space Weather Science Investigations

Atmosphere ◽

10.3390/atmos10120749 ◽

2019 ◽

Vol 10 (12) ◽

pp. 749 ◽

Cited By ~ 2

Author(s):

Catia Grimani ◽

Daniele Telloni ◽

Simone Benella ◽

Andrea Cesarini ◽

Michele Fabi ◽

...

Keyword(s):

Large Scale ◽

European Space Agency ◽

Cosmic Ray ◽

High Energy ◽

Interplanetary Coronal Mass Ejections ◽

Particle Detectors ◽

Space Agency ◽

Interplanetary Plasma ◽

Galactic Cosmic Ray ◽

Science Investigations

The role of high-energy particles in limiting the performance of on-board instruments was studied for the European Space Agency (ESA) Laser Interferometer Space Antenna (LISA) Pathfinder (LPF) and ESA/National Astronautics and Space Administration Solar Orbiter missions. Particle detectors (PD) placed on board the LPF spacecraft allowed for testing the reliability of pre-launch predictions of galactic cosmic-ray (GCR) energy spectra and for studying the modulation of proton and helium overall flux above 70 MeV n − 1 on a day-by-day basis. GCR flux variations up to approximately 15% in less than a month were observed with LPF orbiting around the Lagrange point L1 between 2016 and 2017. These variations appeared barely detected or undetected in neutron monitors. In this work the LPF data and contemporaneous observations carried out with the magnetic spectrometer AMS-02 experiment are considered to show the effects of GCR flux short-term variations with respect to monthly averaged measurements. Moreover, it is shown that subsequent large-scale interplanetary structures cause a continuous modulation of GCR fluxes. As a result, small Forbush decreases cannot be considered good proxies for the transit of interplanetary coronal mass ejections and for geomagnetic storm forecasting.

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Retieving antenna miss-pointing for vertical pointing cloud radar and correcting the introduced Doppler velocity errors in the measurements

10.5194/ems2021-293 ◽

2021 ◽

Author(s):

Lukas Pfitzenmaier ◽

Pavlos Kollias ◽

Ulrich Löhnert

Keyword(s):

Prediction Models ◽

Weather Prediction ◽

Convective Motion ◽

Doppler Velocity ◽

Velocity Measurements ◽

Wind Fields ◽

Satellite Mission ◽

Fall Velocity ◽

Particle Sedimentation ◽

Retrieval Technique

In the last decades, Doppler velocity measurements from zenith pointing radars have evolved to a standard radar variable. Measuring Doppler velocities allow estimating particle sedimentation or fall velocity of hydrometeors and thus offer key information to evaluate micro-physical parametrizations in numerical weather prediction models. In the future, the joint ESA-JAXA satellite mission EarthCARE features the first Doppler capable 94-GHz Cloud Profiling Radar (CPR), with enhanced sensitivity and improved resolution compared to the CloudSat CPR. These features, especially the Doppler velocity measurements, are expected to improve the CPR-based microphysical retrievals in clouds and precipitation and for the first time provide information about convective motion in clouds.To evaluate EarthCare CPR Doppler velocity from the ground, the Doppler velocity from five ground-based zenith pointing 94 GHz radar spread over Europa should be used in future. To increase the quality of the measured Doppler velocity the antenna miss-pointing has to be estimated. Unknown antenna miss-pointing is the main source of error in Doppler velocity measurements and can reach values on the same order as the fall velocity of pristine ice crystals. Knowing the angle of miss-pointing, the error in the measured Doppler velocity measurements can be corrected and the precision and quality improved. This is especially important for cases where Doppler velocity values are direct input for retrievals, which, e.g., employ multiple radar sensors with matching sampling(?) volumes.Within this work we will present a retrieval technique to identify the angle of antenna miss-pointing for ground-based radar profilers and correct the measured Doppler velocity values. The retrieval technique is a statistical method requiring the uncorrected Doppler velocity measurements and additional wind information from reanalysis or in parallel measuring sensors. Evaluation of the retrieval was done using different wind input data sets, e.g., ECMWF IFS wind fields or retrieved wind information from Radar scans. Also, the retrieval was used to correct the miss-pointing angles of two in parallel measuring zenith pointing radars and, therefore, correct the velocity errors in dual Doppler velocity field. &#160;

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