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MAUSAM ◽  
2022 ◽  
Vol 53 (2) ◽  
pp. 153-164
Author(s):  
M. DAS GUPTA ◽  
S. R. H. RIZVI ◽  
A. K. MITRA

The near surface scatterometer wind data from the European remote sensing satellite ERS-2 of European space agency(ESA) became available at NCMRWF on real time basis since February 1997. An attempt has been made to assimilate this data in the global data assimilation system(GDAS) operational at NCMRWF after proper quality control to study its impact on the analysis as well as on medium range weather forecast over the tropics. For this purpose the GDAS was run for 15 days (27 May to 10 June 1998). The impact has been examined through circulation characteristics and various objective scores. The study revealed that with proper quality control the scatterometer wind data can be assimilated in real time basis, resulting in an overall improvement in performance of the analysis-forecast system.


2022 ◽  
Author(s):  
Stefan Möstl ◽  
Fabian Hoffmann ◽  
Jan-Niklas Hönemann ◽  
Jose Ramon Alvero-Cruz ◽  
Jörn Rittweger ◽  
...  

Aim. Pulse wave velocity independently predicts cardiovascular risk. Easy to use single cuff oscillometric methods are utilized in clinical practice to estimate pulse wave velocity. We applied the approach in master athletes to assess possible beneficial effects of lifelong exercise on vascular health. Furthermore, we compared single cuff measurements with a two-cuff method in another cohort. Methods. We obtained single cuff upper arm oscillometric measurements thrice in 129 master athletes aged 35 to 86 years and estimated pulse wave velocity using the ArcSolver algorithm. We applied the same method in 24 healthy persons aged 24 to 55 years participating in a head down tilt bedrest study. In the latter group, we also obtained direct pulse wave velocity measurements using a thigh cuff.Results. Estimated pulse velocity very highly correlated with age (R2 = 0.90) in master athletes. Estimated pulse wave velocity values were located on the same regression line like values obtained in participants of the head down tilt bed rest study. The modest correlation between estimated and measured PWV (r² 0.40; p<0.05) was attenuated after adjusting for age; the mean difference between pulse wave velocity measurements was 1 m/s.Conclusion. Estimated pulse wave velocity mainly reflects the entered age rather than true vascular properties and, therefore, failed detecting beneficial effects of life long exercise.Funding. The AGBRESA-Study was funded by the German Aerospace Center (DLR), the European Space Agency (ESA, contract number 4000113871/15/NL/PG) and the National Aeronautics and Space Administration (NASA, contract number 80JSC018P0078). Fabian Hoffmann received funding by the DLR and the German Federal Ministry of Economy and Technology, BMWi (50WB1816). SM, JT and JJ were supported by the Austrian Federal Ministry for Climate Action, Environment, Energy, Mobility, Innovation and Technology, BMK (SPACE4ALL Project, FFG No. 866761).


2022 ◽  
Vol 15 (1) ◽  
pp. 185-203
Author(s):  
Frithjof Ehlers ◽  
Thomas Flament ◽  
Alain Dabas ◽  
Dimitri Trapon ◽  
Adrien Lacour ◽  
...  

Abstract. The European Space Agency (ESA) Earth Explorer Mission Aeolus was launched in August 2018, carrying the first Doppler wind lidar in space. Its primary payload, the Atmospheric LAser Doppler INstrument (ALADIN), is an ultraviolet (UV) high-spectral-resolution lidar (HSRL) measuring atmospheric backscatter from air molecules and particles in two separate channels. The primary mission product is globally distributed line-of-sight wind profile observations in the troposphere and lower stratosphere. Atmospheric optical properties are provided as a spin-off product. Being an HSRL, Aeolus is able to independently measure the particle extinction coefficients, co-polarized particle backscatter coefficients and the co-polarized lidar ratio (the cross-polarized return signal is not measured). This way, the retrieval is independent of a priori lidar ratio information. The optical properties are retrieved using the standard correct algorithm (SCA), which is an algebraic inversion scheme and therefore sensitive to measurement noise. In this work, we reformulate the SCA into a physically constrained maximum-likelihood estimation (MLE) problem and demonstrate a predominantly positive impact and considerable noise suppression capabilities. These improvements originate from the use of all available information by the MLE in conjunction with the expected physical bounds concerning positivity and the expected range of the lidar ratio. To consolidate and to illustrate the improvements, the new MLE algorithm is evaluated against the SCA on end-to-end simulations of two homogeneous scenes and for real Aeolus data collocated with measurements by a ground-based lidar and the Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO) satellite. The largest improvements were seen in the retrieval precision of the extinction coefficients and lidar ratio ranging up to 1 order of magnitude or more in some cases due to effective noise dampening. In real data cases, the increased precision of MLE with respect to the SCA is demonstrated by increased horizontal homogeneity and better agreement with the ground truth, though proper uncertainty estimation of MLE results is challenged by the constraints, and the accuracy of MLE and SCA retrievals can depend on calibration errors, which have not been considered.


Author(s):  
M. Benchelha ◽  
F. Benzha ◽  
H. Rhinane ◽  
A. Zilali

Abstract. Wetlands are considered as sensitive ecosystems exposed and threatened by climate change and the urbanization of natural environments. In the purpose of managing these sensitive areas and conservatizing their biodiversity, remote sensing is an efficient way to track environmental variables over large areas as wetlands. However, when it comes to the study of hydrologic dynamics, high temporal and spatial resolutions are essential. Since the access to optical satellite imagery is restrictive because of the large cloud cover that masks the ground, radar sensors that are working in the microwave field, are particularly suited to the characterization of hydrological dynamics due to the sensitivity of their measurements in the presence of water, regardless of the vegetation in place. Recently, radar remote sensing has experienced a real revolution with the launch of the Sentinel-1A satellite in 2014, followed by its twin Sentinel-1B two years later by the European Space Agency as part of the Copernicus program. These sensors acquire C-band data (λ = 5.6 cm) with a temporal resolution of 12 days by satellite and their distribution is open and free. This article aims to assess the potential of Sentinel A1 SAR data for wetland mapping in the city of Benslimane (Central Morocco). The first part is explaining the methodology for mapping water surfaces. We identified a confusion of the C-band radar response of water surfaces and that of certain bare soils. We then showed that the VH polarization is the most suitable for the mapping of water surfaces, comparing four methods of detecting areas in water. It. The second part is discussing the use of unsupervised methods without a priori data demonstrating that the methods taking into account the spatial neighborhood give better results. Temporal filtering has been developed and has made it possible to improve detection and to overcome confusion between bare soil and permanent water surfaces. Water surfaces larger than 0.5 ha are at 80% detected. Classification was performed using the SVM (Support Vector Machine) algorithm. This latter information was then implemented into the thematic map derived from SPOT-4 images to obtain the final weltands map.


Author(s):  
Christian Siemes ◽  
Stephen Maddox ◽  
Olivier Carraz ◽  
Trevor Cross ◽  
Steven George ◽  
...  

AbstractCold Atom technology has undergone rapid development in recent years and has been demonstrated in space in the form of cold atom scientific experiments and technology demonstrators, but has so far not been used as the fundamental sensor technology in a science mission. The European Space Agency therefore funded a 7-month project to define the CASPA-ADM mission concept, which serves to demonstrate cold-atom interferometer (CAI) accelerometer technology in space. To make the mission concept useful beyond the technology demonstration, it aims at providing observations of thermosphere mass density in the altitude region of 300–400 km, which is presently not well covered with observations by other missions. The goal for the accuracy of the thermosphere density observations is 1% of the signal, which will enable the study of gas–surface interactions as well as the observation of atmospheric waves. To reach this accuracy, the CAI accelerometer is complemented with a neutral mass spectrometer, ram wind sensor, and a star sensor. The neutral mass spectrometer data is considered valuable on its own since the last measurements of atmospheric composition and temperature in the targeted altitude range date back to 1980s. A multi-frequency GNSS receiver provides not only precise positions, but also thermosphere density observations with a lower resolution along the orbit, which can be used to validate the CAI accelerometer measurements. In this paper, we provide an overview of the mission concept and its objectives, the orbit selection, and derive first requirements for the scientific payload.


2022 ◽  
Vol 14 (4) ◽  
pp. 58-66
Author(s):  
Aleksandr Kozyukov ◽  
N. Gamzatov ◽  
Sergey Grechanyy ◽  
Konstantin Zolnikov ◽  
I. Strukov ◽  
...  

The analysis of information on the stability of the electronic component base (ECB) in the development of radio-electronic equipment (REE) of spacecraft (spacecraft) is an important and urgent task. The paper considers the main components of the approaches of foreign organizations developing radio space technology to ensure its radiation resistance. The design approaches of Thales Alenia Space, Airbus Defense and Space, and the European Space Agency are presented. The article outlines the main directions for optimizing the procedures for the preliminary selection of ECB, which consist in ensuring the required resistance of REE SC at the ECB level with ensuring the reliability of data on durability, in minimizing the costs of applying resistance enhancement measures (through the use of a promising ECB with increased resistance characteristics), to replace ECB.


Author(s):  
Martin Azkarate ◽  
Levin Gerdes ◽  
Tim Wiese ◽  
Martin Zwick ◽  
Marco Pagnamenta ◽  
...  

2022 ◽  
Vol 2161 (1) ◽  
pp. 012037
Author(s):  
Abhijit Banerjee ◽  
Rina Bhattacharya

Abstract The very inquisition of the humanity always remains about its parent star of this planetary system. Scientists across the world are always egger to investigate the details of the phenomenon of the solar flares and coronal mass ejections (CMEs). There are some fundamental mysteries related to the solar coronal heating along with the acceleration of the solar wind and energetic particles. In this context we have discussed on the solar radio signal data obtained from the Parker Solar Probe (PSP) mission of National Aeronautics and Space Administration (NASA), USA in course of its journey towards the Sun and the very recent data of Solar and Heliospheric Observatory (SOHO) space probe of European Space Agency (ESA) and NASA. In this work the simultaneous and periodical analysis of the data from the SOHO and PSP will light into the delicate features of the near and far Earth observations on the solar coronal mass ejections related dynamics and that reveals some interesting facts in relation to the solar magnetic field.


2022 ◽  
Vol 964 (1) ◽  
pp. 012007
Author(s):  
Hoang Phi Phung ◽  
Lam Dao Nguyen ◽  
Nguyen Van Anh Vu ◽  
Nguyen Kim Thanh ◽  
Le Van Trung

Abstract Rice is one of the main agricultural crops and plays an important role in food security. Therefore, it is essential to propose a method for monitoring the distribution of rice yield. Radar remote sensing data sources provide a sustainable solution for rice monitoring challenges in the countries located in the tropical monsoon region like Vietnam. The SAR (Synthetic Aperture Radar) remote sensing data from the Sentinel-1 satellite provided by the European Space Agency (ESA) is free of charge, has a large coverage and high spatial-temporal resolution. In this paper, rice growing areas in the An Giang province of Vietnam Mekong Delta were analyzed, which demonstrates the potential applications of multi-temporal data and proposes a method to estimate rice yield for agricultural management. The analysis results showed that in 2018 the Winter-Spring rice crop has the highest yield, and the Autumn-Winter crop has the lowest yield. Accurate and timely estimation of rice yield and production can provide important information in terms of spatial distribution and seasonal yield for government and decision-makers in policy making related to import and export.


2021 ◽  
Vol 14 (12) ◽  
pp. 7975-7998
Author(s):  
Bianca Maria Dinelli ◽  
Piera Raspollini ◽  
Marco Gai ◽  
Luca Sgheri ◽  
Marco Ridolfi ◽  
...  

Abstract. The observations acquired during the full mission of the Michelson Interferometer for Passive Atmospheric Sounding (MIPAS) instrument, aboard the European Space Agency Environmental Satellite (Envisat), have been analysed with version 8.22 of the Optimised Retrieval Model (ORM), originally developed as the scientific prototype of the ESA level-2 processor for MIPAS observations. The results of the analyses have been included into the MIPAS level-2 version 8 (level2-v8) database containing atmospheric fields of pressure, temperature, and volume mixing ratio (VMR) of MIPAS main targets H2O, O3, HNO3, CH4, N2O, and NO2, along with the minor gases CFC-11, ClONO2, N2O5, CFC-12, COF2, CCl4, CF4, HCFC-22, C2H2, CH3Cl, COCl2, C2H6, OCS, and HDO. The database covers all the measurements acquired by MIPAS in the nominal measurement mode of the full resolution (FR) part of the mission (from July 2002 to March 2004) and all the observation modes of the optimised resolution (OR) part (from January 2005 to April 2012). The number of species included in the MIPAS level2-v8 dataset makes it of particular importance for the studies of stratospheric chemistry. The database is considered by ESA the final release of the MIPAS level-2 products. The ORM algorithm is operated at the vertical grid coincident to the tangent altitudes of the observations or to a subset of them, spanning (in the nominal mode) the altitude range from 6 to 68 km in the FR phase and from 6 to 70 km in the OR period. In the latitude domain, FR profiles are spaced by about 4.7∘, while the OR profiles are spaced by about 3.7∘. For each retrieved species, the auxiliary data and the retrieval choices are described. Each product is characterised in terms of the retrieval error, spatial resolution, and “useful” vertical range in both phases of the MIPAS mission. These depend on the characteristics of the measurements (spectral and vertical resolution of the measurements), the retrieval choices (number of spectral points included in the analyses, number of altitudes included in the vertical retrieval grid), and the information content of the measurements for each trace species. For temperature, water vapour, ozone, and nitric acid, the number of degrees of freedom is significantly larger in the OR phase than in the FR one, mainly due to the finer vertical measurement grid. In the FR phase, some trace species are characterised by a smaller retrieval error with respect to the OR phase, mainly due to the larger number of spectral points used in the analyses, along with the reduced vertical resolution. The way of handling possible caveats (negative VMR, vertical grid representation) is discussed. The quality of the retrieved profiles is assessed through four criteria, two providing information on the successful convergence of the retrieval iterations, one on the capability of the retrieval to reproduce the measurements, and one on the presence of outliers. An easy way to identify and filter the problematic profiles with the information contained in the output files is provided. MIPAS level2-v8 data are available to the scientific community through the ESA portal (https://doi.org/10.5270/EN1-c8hgqx4).


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