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The significant role dust aerosols play in the earth's climate system and microbial nutrition cycles have lead to increased efforts of employing remote sensing to monitor their genesis, transport and deposition. This contribution extends earlier approaches of using Bayesian hierarchical models to extract dust activity from multi-spectral MSG-SEVIRI measurements by focusing on the signal-to-noise ratio...
A novel technique for removal of scalloping in ScanSAR images is proposed. Scalloping artifact is modeled by gain and offset parameters exhibiting periodic variations as function of azimuth time. In proposed technique, Kalman filter is used to find minimum mean square error estimates of gain and offset parameters are found out for each azimuth position in a sub-swath. The range samples at a certain...
A novel technique for despeckling of synthetic aperture radar (SAR) is proposed. A predefined number of overlapping subsets of pixels are selected from SAR image. Each subset is comprised of pixels selected from uniformly distributed locations. The subsets of pixels are elected in such a way that at least 20% of pixels in any subset should be different from pixels in any other subset. By considering...
This paper discusses the effect of superimposed-Fast Fourier Transforms on synthetic aperture radar (SAR) image formation. In a Fourier Transform, the band-limited property in measured signals causes relatively high sidelobes, which tends to corrupt the “target” or “Image” detected. One technique to reduce side-lobes is windowing; nonetheless, this will also have a broadening effect on the main-lobe...
This paper proposes a novel speckle reduction method that combines an advanced statistical distribution with spatial contextual information for SAR data. The method for despeckling is based on a Markov random field (MRF) that integrates a K-distribution for the SAR data statistics and a Gauss-MRF model for the spatial context. These two pieces of information are combined based on weighted summation...
A new suite of instruments to estimate atmospheric ozone by measuring scattered solar irradiance began operating in January 2012. The measurements will be used to continue existing records of atmospheric ozone profiles as part of the NOAA Joint Polar Satellite System. This paper presents preliminary evaluations of these new products.
Both the imagery and VCM validation efforts required extensive coordination with users and other validation teams, along with the validation effort itself. Therefore the validation efforts from the very beginning included both the work necessary to validate the products as well as efficient mechanisms to communicate with external dependent communities.
The Ocean Color CAL/VAL team is evaluating the VIIRS bio-optical products for real-time operations. VIIRS ocean data are being processed using standard government algorithms, and channel calibration and product validation evaluation activities are ongoing. A network of 27 global “Golden Regions” has been established to evaluate and validate bio-optical products. Satellite inter-comparison for data...
This paper reports on the recent status of the validation program for the Suomi National Polar-orbiting Partnership (NPP) Cross-track Infrared Microwave Sounding Suite (CrIMSS), a hyperspectral infrared sounding system designed for providing high resolution atmospheric vertical temperature and moisture profile (AVTP and AVMP) environmental data records (EDRs). CrIMSS EDR validation activities, currently...
This paper reports on systematic height offsets that have been observed in TanDEM-X by evaluating a large number of digital elevation model (DEM) acquisitions. Besides the expected instrument and baseline offsets, which are compensated in the calibration chain, two unexpected external error sources have been identified that apply to any formation flying bistatic SAR interferometer. The first contribution...
Azimuth ambiguities affect the interferometric performance of SAR systems, causing a bias in the interferometric phase and a modulation of the interferometric coherence, as also visible in some TanDEM-X interferograms. This paper provides an explanation for this phenomenon and derives the analytical expressions for the phase bias and the coherence, resorting to the interferogram statistics for jointly...
The TanDEM-X mission based on two satellites provides a radar interferometer in space with the goal to derive a global Digital Elevation Model (DEM) with never achieved quality for a global coverage: a global DEM with a relative height accuracy of 2m and 10m absolute. In order to achieve this mission goal, the distance between both satellites, the so called baseline has to be known extreme precisely...
The cooperative nature of the TanDEM-X mission bistatic operation allows the periodically exchange of information between transmitter and receiver over the SAR acquisition. With the information gathered during the synchronization (sync) events it is possible to perform the phase and time referencing necessary for the calibration of the bistatic SAR image. However, given that transmitter and receiver...
We present results from the LORAMbis bistatic VHF/UHF-band SAR experiment conducted in September 2010. The SAR flights were performed with the French SETHI system and the Swedish LORA system installed in two aircraft. Frequency band was 222–460 MHz and polarization was HH. Results from two tests sites (Kvarn and Remningstorp, both in southern Sweden) show that forest clutter generally decreases for...
Airborne bistatic SAR data have been collected at VHF- and UHF-band to investigate clutter suppression in forested and urban areas. The synchronization between the SAR systems is accomplished using the 1-PPS signal provided by the GPS system. The same signal is also used as input to a disciplined 10 MHz master oscillator integrated in both radar systems to maintain sufficient phase stability. Images...
The interpolation-based Polar Format Algorithm (PFA) can be used in bistatic Synthetic Aperture Radar (SAR) image processing while suffering from heavy interpolation computation load and complicated space-dependent resolution. To decrease computation load, this paper presents a nonlinear trajectory-based PFA, in which sensors are designed to fly on conical surface to avoid range interpolation. Due...
Spatial synchronization and its importance in the imaging performance of bistatic synthetic aperture radar (SAR) systems has been explored in several recent studies. In this paper, attitude measurement errors (AME) are studied in the context of motion measurement errors (MME) since the transmitting and receiving antennas are attached to rigid bodies that undergo both translational and rotational motion...
The acquisition of Synthetic Aperture Radar (SAR) data in a bistatic forward-looking configuration offers many new capabilities for a broad spectrum of remote sensing applications. A radar system in an aircraft could image the runway during the landing approach to improve landing safety, particularly in poor visibility conditions. First experiments and imaging results demonstrate the feasibility of...
Both CloudSat and TRMM/PR data are utilized to characterize the cloud-precipitation system globally and several analysis methods are proposed in this paper: combined contoured frequency by altitude diagram (CFAD), combined echo area, and size/height/strength diagram. The global map of CFAD (10 × 10 degree boxes) shows good correspondence with the conventional climate classification and also the diurnal...
In this study, a TRMM_based temporal analysis of precipitation (2000 to 2010), at the watershed scale, was conducted in the pursuit of understanding annual and seasonal precipitation trends relatively to major conversion patterns in the Brazilian savanna biome. It could be observed a significant difference in terms of mean precipitation between conservation scenarios and, mostly important, smaller...
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