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Surface soil moisture was retrieved globally by systematically correcting for the effects of vegetation and soil surface roughness. The retrieval is enabled by employing physical-models of radar forward scattering for individual vegetation types to account for vegetation scattering and absorption, and by constraining the surface roughness effect using time-series observations. The L-band SMAP multi-polarized...
We have concluded that before calculation of the AirMOSS project overall RMSE, not only the behavior and location of in-situ soil moisture probes need to be carefully evaluated but also the present error biases—associated with the in-situ probes, radar calibration, vegetation parameterization, forward model inaccuracy, and the inversion algorithm bias—need to be removed. Several measures have been...
The Chinese and French Space Agencies are jointly preparing an innovative mission, CFOSAT (China France Oceanography Satellite) devoted to the monitoring of the ocean surface and its related science and applications. This paper gives an overview of the scientific objectives, the mission and instrument characteristics, the expected data products and their performance.
We present in this paper the work done to test the synoptic capabilities of the GNSS-R interferometric technique as a means towards sea surface altimetry estimation, which is an integrated part of the assessment of the GEROS-ISS mission. For this purpose, a new software receiver has been developed and tested: SPIR. With the lessons learned after a first flight campaign, some system modifications were...
Improved soil moisture estimation, within a combined radar-radiometer framework, by using Joint-physics modeling is demonstrated and presented in this work. Detailed numerical simulation on bare, but rough surfaces, highlight how improved emission-scattering modeling, can outperform conventional approaches. Root-mean-squared error statistics show almost a factor of two improvement in soil permittivity...
In June 2015 the TRMM satellite came to its end. The 17+ year of mission data that it provided has proven a valuable asset to a variety of science communities. This 17+ year data set does not, however, stagnate with the end of the mission itself. NASA/JAXA intend to integrate the TRMM data set into the data suite of the GPM mission. This will ensure the creation of a consistent, intercalibrated, accurate...
We carried out the intensive observation for the GPM/DPR ground validation at Mt. Zao during 2014–2015 winter season, targeting the melting layer. For the better understanding of microphysics in the melting layer, we developed Ground-based Particle Image and Mass Measurement System (G-PIMMS). It can capture particle images by CCD cameras and measure particle weight by the electronic balance. G-PIMMSs...
High Frequency (HF) radar sounder has been employed for the Mars surface/subsurface exploration. To survey the seasonal water flows on Mars surface, which has been reported, the radar sounder echoes from dry surface or water flowing surface are numerically simulated, respectively. Simulation results show that the radar echoes from water flowing surface is significantly larger than the dry surface,...
With emphasis on physics-based techniques, a multi-objective optimization approach to combined radar-radiometer soil moisture estimation is presented in this work. Soil moisture estimation is demonstrated via application of this method to SMAP high resolution radar and coarse resolution radiometer data. Comparisons are then made with the SMAP baseline active-passive soil moisture output data product...
Interferometric Synthetic Aperture Radar (InSAR) methods provide high resolution maps of surface deformation applicable to many scientific, engineering and management studies. Modern spaceborne satellites provide long sequences of observations that we can reduce to many interferograms, which in turn provide the deformation histories of many points on the surface. Here we show how raw radar data, or...
In the radar imaging of the object above three-dimensional (3-D) ocean surface, the multipath scattering brings in artifacts which can be reckoned as the distorted and shifted replicas of the direct-path scatters. As it is the propagation delays that play an important role in the understanding of these artifacts, this paper proposes a probability model of the multipath delays for the scatters above...
Waveforms with low autocorrelation sidelobes are favorable to weak target detection and synthetic aperture radar (SAR) imaging. In this paper, we aim at solving the problem of designing waveforms with low autocorrelation sidelobes at specified intervals. Thus an amplitude optimization method (AOM) is proposed to minimize the weighted integrated sidelobe level (WISL) of the autocorrelation. By regarding...
The Soil Moisture Active Passive (SMAP) observatory was launched January 31, 2015, and its L-band radiometer and radar instruments became operational during April 2015. The SMAP radiometer has been operating flawlessly, however the radar transmitter ceased operation on July 7. This paper provides a summary of the calibration and validation of the SMAP instruments and the current quality assessment...
The Soil Moisture Active Passive (SMAP) mission launched on Jan 31, 2015. The mission employs L-band radar and radiometer measurements to estimate soil moisture with 4\% volumetric accuracy at a resolution of 10 km, and freeze-thaw state at a resolution of 1–3 km [1]. Immediately following launch, there was a three month instrument checkout period, followed by six months of level 1 (L1) calibration...
In statistical classification, such mixture models allow a formal approach to unsupervised clustering. Fitting mixture distributions can be handled by a wide variety of techniques. A standard method to fit finite mixture models to observed data is the Expectation-Maximization (EM) algorithm which is an iterative procedure which converges to a (local) maximum of the marginal a posteriori probability...
This paper investigates the capability of a miniaturized radar sensor developed for Micro Aerial Vehicles (MAVs) to cope with complex mission scenarios that involve integrating and satisfying either Synthetic Aperture Radar (SAR) or Interferometric SAR and navigation and Sense-and-Avoid (SAA) requirements. A radar sensor based on Frequency Modulated Continuous Wave (FMCW) technology developed by IMST...
SWIM is part of the CFOSAT satellite mission payload. It is designed for the measurement of directional ocean wave spectra. It is a Ku-band real-aperture radar with 6 rotating fan-beams pointing near nadir. The main characteristics of the instrument, data, products are presented in this paper, as well as performances estimated from simulations.
The most popular model-based decompositions (MBD) are reconsidered in the context of the estimation theory. It is shown that a large processing window is required to reduce the bias on the individual scattering contribution due the target scattering Reflection symmetry assumption. This limits the MBD efficiency in areas of non stationarity radar backscattering, such as urban areas. Eigenvector-based...
Dual-frequency precipitation radar (DPR) on board the GPM (Global Precipitation Measurement) core satellite has reflectivity measurements at two different frequency bands namely, Ku- and Ka- band. Dual-frequency ratio from these measurements has been used to perform rain type classification and melting region detection in the dual-frequency classification module in the current DPR level 2 algorithm...
Post-fire forest regeneration is crucial to both ecological studies and forest management. Three restoration treatments, namely natural regeneration (NR), artificial regeneration (AR), and artificial promotion (AP), were adopted in the Greater Hinggan Mountain area of China after a serious fire occurred on May 6, 1987. NR means recovering naturally without any intervention, AR comprises salvage logging...
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