An enhanced resolution brightness temperature product for future conical scanning microwave radiometers

An enhanced spatial resolution brightness temperature product is proposed for future conical scan microwave radiometers. The technique is developed for Copernicus Imaging Microwave Radiometer (CIMR) measurements that are simulated using the CIMR antenna pattern at the L-band and the measurement geometry proposed in the Phase A study led by Airbus. An inverse antenna pattern reconstruction method is proposed. Reconstructions are obtained using two CIMR configurations, namely, using measurements collected at L-band by the forward (FWD) scans only, and combining forward and backward (FWD+BWD) scans. Two spatial grids are adopted, namely, 3 km x 3 km and 36 km x 36 km. Simulation results, referred to synthetic and realistic reference brightness fields, demonstrate the soundness of the proposed scheme that provides brightness temperature fields reconstructed at a spatial resolution up to ~ 1.9 times finer than the measured field when using the FWD+BWD combination.The work of Claudio Estatico was supported in part by the Gruppo Nazionale di Calcolo Scientifico–Istituto Nazionale di Alta Matematica (GNCS-INDAM), Italy. This work has been produced for the European Space Agency (ESA) in the frame of the Copernicus Program as a partnership between ESA and the European Commission.Peer ReviewedPostprint (author's final draft

Remote sensing satellite image processing techniques for image classification: a comprehensive survey

This paper is a brief survey of advance technological aspects of Digital Image Processing which are applied to remote sensing images obtained from various satellite sensors. In remote sensing, the image processing techniques can be categories in to four main processing stages: Image preprocessing, Enhancement, Transformation and Classification. Image pre-processing is the initial processing which deals with correcting radiometric distortions, atmospheric distortion and geometric distortions present in the raw image data. Enhancement techniques are applied to preprocessed data in order to effectively display the image for visual interpretation. It includes techniques to effectively distinguish surface features for visual interpretation. Transformation aims to identify particular feature of earth’s surface and classification is a process of grouping the pixels, that produces effective thematic map of particular land use and land cover

Measurement and analysis of aerosols, cirrus-contrails, water vapor and temperature in the upper troposphere with the Jungfraujoch LIDAR system

The impact of human activities on the global climate may lead to large disruptions of the economic, social and political status quo in the middle and long term. Understanding the dynamics of the Earth's climate is thus of paramount importance and one of the major scientific challenges of our time. The estimation of the relative contribution of the many components (interacting each other) of the Earth's climate system requires observation and continuous monitoring of various atmospheric physical and chemical parameters. Temperature, water vapor and greenhouse gases concentration, aerosol and clouds loads, and atmospheric dynamics are parameters of particular importance in this respect. The quantification of the anthropogenic influence on the dynamics of these above-mentioned parameters is of crucial importance nowadays but still affected by significant uncertainties. In the present context of these huge uncertainties in our understanding of how these different atmospheric compounds contribute to the radiative forcing, the research presented in this report is related to the following topics: Development of lidar-based remote sensing techniques for monitoring atmospheric compounds and processes Aerosols – cirrus – contrails optical properties up to the tropopause Water vapor mixing ratio and relative humidity estimation in the upper troposphere Temperature profiling in the upper troposphere-lower stratosphere Characterization of the long-range transported mineral aerosols (i.e. Saharan dust outbreaks) Planetary boundary layer-upper troposphere exchanges (i.e. August 2003 heatwave effect) In the above research frames, the development and application of measurement techniques for the monitoring of climate-change parameters, this work refers to the implementation of a multi-wavelength LIDAR1 system (JFJ - LIDAR)2 at the International Scientific Station of Jungfraujoch (ISSJ, 46°33' N, 7°59' E, at 3580 m ASL- above sea level). The JFJ3 station is situated above the planetary boundary layer (PBL) almost all year long and is located in a mountain pass linking the Swiss plateau to the North with the Rhone Valley to the South through the Aletsch glacier corridor. Measurements with the JFF-LIDAR system provide regular vertical and horizontal remote sensing of water vapor, temperature, and optical properties (backscatter and extinction coefficients) of aerosols, cirrus clouds and contrails in the upper troposphere (UT)4. The lidar system is based on the laser emission at 355, 532 and 1064 nm and on subsequent detection of both elastic (Mie) and inelastic (Raman) atmospheric backscatter light. The backscattering collected radiation is precisely: the elastic at 355, 532 and 1064 nm; the rotational-vibrational Raman radiation from nitrogen at ~ 387 nm, and from water vapor at ~ 407 nm as well as the pure rotational nitrogen/oxygen Raman excited at ~ 532 nm. The depolarization of the initially linearly polarized radiation was also detected at 532 nm and it was use to distinguish between water and ice contents in cirrus clouds, but also it may reveal long-range transported mineral aerosols such as Saharan dust. Profiles of backscatter and extinction coefficients of aerosols-cirrus-contrails, needed for estimation of the radiative balance of the atmosphere, are derived from elastic and Raman light scattering processes, or through a combination of both, using devoted algorithms and software developed within this research. Data gathered from routine measurements are statistically analyzed and interpreted in comparison with similar measurements obtained from colocated techniques. Optical and microphysical properties of a typical contrail were studied. The UT water vapor mixing ratio profiles are estimated from the ratio of ~ 407 nm and ~387 nm Raman radiation excited by 355 nm. Upon appropriate calibration, real time water vapor mixing ratio profiles derived from LIDAR measurements are found in good agreement with the closest radiosounding techniques, and co-located measurements such as the GPS5 and sun photometer based measurements. The water vapor profiles, combined with simultaneous temperature profiles taken from atmospheric models, radiosounding or, more realistically, based on the pure rotational Raman technique, were used for the estimation of relative humidity profiles which allow the identification of UT super-saturation regions. Air temperature profiles were obtained up to the lower stratosphere using the backscatter of pure rotational Raman radiation excited by 532 nm. These first results compare well to simultaneous regional radiosounding measurements, and follow standard atmospheric models. The pure rotational Raman backscatter was also used for determining absolute extinction and the lidar ratio for cirrus clouds. Based on the JFJ-LIDAR measurements, supported by co-located and regional measurements, the research presents also in detail two case studies related to climate problematic: The first concerns the tracking of a Saharan dust outbreak (SDO) and the derivation of its optical properties. The second study refers to the analysis of the evolution and consequences of the high altitudes planetary boundary layer (PBL)6 convection during the August 2003 heat - wave episode. The results presented within this research provide a promising basis for extending these JFJ-LIDAR observations from the upper troposphere into the stratosphere by using the existent astronomic telescope (~15 times increased sensitivity) and a new (~ 3 times more powerful) laser source. Consequently DIAL7 technique for measuring the stratospheric ozone will be developed and implemented in the near future at JFJ. Future challenges include also JFJ-LIDAR remote control operation and the ability of real time obtained atmospheric calibrated profiles (i.e. optical properties of aerosols-cirruscontrails, water vapor, temperature and ozone). --------------------1 LIDAR – LIght Detection And Ranging 2 JFJ-LIDAR is the acronym used here for Jungfraujoch multi-wavelength LIDAR system 3 JFJ is the abbreviation for Jungfraujoch 4 UT will be used as abbreviation for upper troposphere (from ~ 3600 m ASL to the tropopause atmospheric region) 5 GPS is the acronym for Global Positioning System 6 PBL - planetary boundary layer – its top is usually situated under the altitude of the JFJ station (i.e. 3600m ASL) 7 DIAL - is the acronym coming from DIfferential Absorption Lida

An Experimental and Numerical Study on the Heat Transfer Driven Dynamics and Control of Transient Variations in a Solar Reactor

University of Minnesota M.S.M.E. thesis.July 2019. Major: Mechanical Engineering. Advisor: Nesrin Ozalp. 1 computer file (PDF); xiv, 156 pages.There is a major challenge in utilization of concentrating solar power for stable energy conversion processes due to fluctuating nature of available irradiation. This challenge can be handled by development of a robust control system that is capable of absorbing fluctuations in the sun’s irradiance without significantly changing the flow dynamics. In this thesis, a heat transfer driven model predictive control system is developed for advanced control of changes in solar flux by implementing a heat exchanger coupled variable aperture mechanism to capture spilled radiation. Experimental testing of the system was performed using a new 10 kWe xenon arc high flux solar simulator which was fully characterized in this thesis. Experimental results showed that the aperture mechanism can maintain the temperature of the reactor within ± 5 °C under severe radiation fluctuations during a cloudy day. Therefore, the aperture mechanism is a promising alternative to current traditional temperature control methods

Development of the Jungfraujoch multiwavelength lidar system for continuous observations of the aerosol optical properties in the free troposphere

Climate changes and global warming are generally associated with the enhanced greenhouse effect, but aerosols can induce a cooling effect and thus regionally mask this warming effect. Unfortunately, the strong variability both in space and in time of the aerosols and thus the difficulty to characterize their global basic properties induce large uncertainties in the predictions of the numerical models. Those uncertainties are as high as the absolute level of the enhanced greenhouse forcing. To solve this problem it is necessary to improve the set of well-calibrated instruments (both in situ and remote sensing) with the ability to measure the changes in stratospheric and tropospheric aerosols amounts and their radiative properties, changes in atmospheric water vapor and temperature distributions, and changes in clouds cover and cloud radiative properties. The quantity used to assess the importance of one compound (greenhouse gases, aerosols) to the variation of the radiative budget of the Earth is the radiative forcing. One of those forcings is the direct aerosol radiative forcing and it depends on the optical depths and the upscatter fraction of the aerosols. Those two parameters depend on the chemical composition and size distribution of the aerosols. Thus the key parameters of this radiative forcing are the chemical composition through its refractive index and the size distribution of the aerosols. This thesis deals with the design and the implementation of one multi-wavelength lidar system at the Jungfraujoch Alpine Research Station (Alt. 3580m asl). This lidar system is a combination of one standard backscatter lidar and one Raman lidar. Its design have been supported by a ray tracing analysis of the receiver part. The laser transmitter is based on a tripled Nd:YAG laser and the backscattered light is collected by one Newtonian telescope for the tropospheric measurements and by one Cassegrain telescope for the future stratospheric measurements. The received wavelengths for each telescope include three elastically scattered wavelengths (355, 532 and 1064nm), two spontaneous Raman signals from nitrogen (387 and 607nm) and one spontaneous Raman signal from the water vapor (408nm). The optical signals received by each of the telescopes are separated spectrally by two filter polychromators. They are build up around a set of beamsplitters and custom design thin band pass filters with high out-of-band rejection. On the visible channel, the adds of a Wollaston prism separates the parallel polarized backscattered signal (532(p)nm) of the perpendicular polarized one (532(c)nm). Photomultiplier tubes perform the detection of the signals for the UV and visible wavelengths and by Si-avalanche photodiodes for the near-infrared signal. The acquisition of the signals is performed by seven transient recorders in analog and in photon counting modes. Within the frame of the EARLINET (European Aerosol Research Lidar Network), hardware and software intercomparisons have been done. The software intercomparison has been divided into the validation of the elastic algorithm and the Raman algorithm. Those intercomparisons of the inversions of the lidar signals have been performed using synthetic data for a number of situations of different complexity. The hardware intercomparison have been achieved with the mobile micro-lidar of the Observatoire Cantonal de Neuchâtel. The present lidar system provides independent aerosol extinction and backscatter profiles, depolarization ratio and water vapor mixing ratio up to the tropopause. Their uncertainties could be smaller than 20% and thus make possible the retrieval of the microphysical aerosol parameters like the volume concentration distribution and the mean and integral parameters of the particle size distribution, (effective radius, total surface-area concentration, total volume concentration and number concentration of particles). This retrieval is performed by one algorithm of the Institute of Mathematic of the University of Postdam based on the hybrid regularization method. The first results of the retrieval of the volume concentration distribution with three backscatter (355, 532 and 1064nm) and one extinction (355nm) profiles has demonstrated promising results. Future upgrades of the system will add ozone concentration and temperature profile up to the stratopause

Accelerated iterative solvers for the solution of electromagnetic scattering and wave propagation propagation problems

The aim of this work is to contribute to the development of accelerated iterative methods for the solution of electromagnetic scattering and wave propagation problems. In spite of recent advances in computer science, there are great demands for efficient and accurate techniques for the analysis of electromagnetic problems. This is due to the increase of the electrical size of electromagnetic problems and a large amount of design and analytical work dependent on simulation tools. This dissertation concentrates on the use of iterative techniques, which are expedited by appropriate acceleration methods, to accurately solve electromagnetic problems. There are four main contributions attributed to this dissertation. The first two contributions focus on the development of stationary iterative methods while the other two focus on the use of Krylov iterative methods. The contributions are summarised as follows: • The modified multilevel fast multipole method is proposed to accelerate the performance of stationary iterative solvers. The proposed method is combined with the buffered block forward backward method and the overlapping domain decomposition method for the solution of perfectly conducting three dimensional scattering problems. The proposed method is more efficient than the standard multilevel fast multipole method when applied to stationary iterative solvers. • The modified improvement step is proposed to improve the convergence rate of stationary iterative solvers. The proposed method is applied for the solution of random rough surface scattering problems. Simulation results suggest that the proposed algorithm requires significantly fewer iterations to achieve a desired accuracy as compared to the conventional improvement step. • The comparison between the volume integral equation and the surface integral equation is presented for the solution of two dimensional indoor wave propagation problems. The linear systems resulting from the discretisation of the integral equations are solved using Krylov iterative solvers. Both approaches are expedited by appropriate acceleration techniques, the fast Fourier transform for the volumetric approach and the fast far field approximation for the surface approach. The volumetric approach demonstrates a better convergence rate than the surface approach. • A novel algorithm is proposed to compute wideband results of three dimensional forward scattering problems. The proposed algorithm is a combination of Krylov iterative solvers, the fast Fourier transform and the asymptotic waveform evaluation technique. The proposed method is more efficient to compute the wideband results than the conventional method which separately computes the results at individual frequency points

2D TSVD to enhance the resolution of radiometer data

A reconstruction technique based on the two-dimensional truncated singular value decomposition (TSVD) is first presented to enhance the spatial resolution of radiometer earth observation (EO) measurements. The technique is physically based on the assumption that the antenna gain function is separable. This hypothesis allows implementing a very computer time effective TSVD-based resolution enhancement technique. Experiments undertaken on a data set of both simulated and real two-dimensional radiometer measurements show a) the accurancy of the proposed approach, b) its robustness against the additive noise level, c) its effectiveness in terms of processing time

Six Decades of Flight Research: An Annotated Bibliography of Technical Publications of NASA Dryden Flight Research Center, 1946-2006

Titles, authors, report numbers, and abstracts are given for nearly 2900 unclassified and unrestricted technical reports and papers published from September 1946 to December 2006 by the NASA Dryden Flight Research Center and its predecessor organizations. These technical reports and papers describe and give the results of 60 years of flight research performed by the NACA and NASA, from the X-1 and other early X-airplanes, to the X-15, Space Shuttle, X-29 Forward Swept Wing, X-31, and X-43 aircraft. Some of the other research airplanes tested were the D-558, phase 1 and 2; M-2, HL-10 and X-24 lifting bodies; Digital Fly-By-Wire and Supercritical Wing F-8; XB-70; YF-12; AFTI F-111 TACT and MAW; F-15 HiDEC; F-18 High Alpha Research Vehicle, F-18 Systems Research Aircraft and the NASA Landing Systems Research aircraft. The citations of reports and papers are listed in chronological order, with author and aircraft indices. In addition, in the appendices, citations of 270 contractor reports, more than 200 UCLA Flight System Research Center reports, nearly 200 Tech Briefs, 30 Dryden Historical Publications, and over 30 videotapes are included