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After the successful launching of the SMOS satellite, the first continuous streams of data are being processed and carefully analyzed in the frame of the SMOS In-Orbit Commissioning phase. Results regarding instrument calibration parameters retrieval, both internal and external, and brightness temperature imaging are presented. Images of ocean, ice and land are given as examples.
In this paper we present a preliminary analysis of the radiometric performance of the three 1.4 GHz Noise Injection Radiometers of the SMOS satellite. We assess the radiometric resolution and stability of the receivers, and the similarity between their measurements. The units aim at measurements of a common antenna temperature, which determines the overall brightness temperature level of SMOS retrievals...
Soil roughness is known to be one important factor affecting the observations of the microwave emission from land surfaces. Natural surfaces show a random roughness profile but many agricultural fields show a tilled row structure with a predominant row direction. To quantify the significance of tillage direction on the emission from soils a series of measurements were carried out with an L-band radiometer...
The European Space Agency (ESA) Soil Moisture and Ocean Salinity (SMOS) mission will provide accurate global surface soil moisture estimates. However, due to technological limitations, the spatial resolution of SMOS observations is limited to 40-km. This resolution is adequate for many global applications, but restricts the use of the data in regional studies over land, where a resolution of 1-10...
In this paper we present a study of a numerical modeling approach based on the Finite Element Method (FEM) for the prediction of rough surface emission at L-band, including a comparison with other modeling approaches and experimental data. The numerical approach relies on the use of ANSYS' numerical computation software HFSS (High Frequency Structure Simulator), which in turn solves Maxwell's equations...
Aquarius is a combination L-band radiometer and scatterometer designed to map the salinity field at the ocean surface from space. It will be flown on the Aquarius/SAC-D mission, a partnership between the USA space agency (NASA) and Argentine space agency (CONAE). The mission is composed of two parts: (a) The Aquarius instrument being developed as part of NASA's Earth System Science Pathfinder (ESSP)...
Field experiment data sets that include coincident remote sensing measurements and in situ sampling will be valuable in the development and validation of the soil moisture algorithms of the NASA's future SMAP (Soil Moisture Active and Passive) mission. This paper presents an overview of the field experiment data collected from SGP99, SMEX02, CLASIC and SMAPVEX08 campaigns. Common in these campaigns...
The CAROLS, L band radiometer, is built and designed as a copy of EMIRAD II radiometer of DTU team. It is a Correlation radiometer with direct sampling and fully polarimetric (i.e 4 Stockes). It will be used in conjunction with other airborne instruments (in particular the C-Band scatterometer (STORM) and IEEEC GPS system, Infrared CIMEL radiometer and one visible camera), in coordination with in...
Our goal is to identify paths to the soil moisture performance objective (soil moisture at depths between 0-80 cm) for US Army and civilian use, and to identify and mitigate algorithm impediments to its potential performance. This work will also enable the Army to more accurately determine the National Polar-orbiting Operational Environmental Satellite System (NPOESS) Soil Moisture Environmental Data...
This work analyzes AMSR-E signatures collected in two sites of La Plata basin, in South America. Within the wide Chaco forest, an area close to Las Lomitas meteorological station was selected. Here the forest is uniform, but not very dense, with biomass values in the range 70-120 t/ha. After strong rain events, appreciable variations of polarization index at C and X band were observed. As expected,...
In the near future two dedicated soil moisture satellites will be launched (SMOS and SMAP), both carrying an L-band radiometer. It is well known that microwave soil moisture retrieval algorithms must account for the physical temperature of the emitting surface. One proposed approach is the use of temperature output from numerical weather prediction (NWP) models. A radiative transfer model, as implemented...
In this paper two algorithms able to generate maps of snow water equivalent and soil moisture content have been developed and implemented within the framework of an Italian project devoted to the civil protection from floods and landslides. The two algorithms are based on Artificial Neural Network techniques and have been first tested on two Italian areas, one an agricultural area in the Po valley...
This paper analyzes the L-band radiometric signatures collected over a Eucalyptus forest with moderate biomass, and compares the results with simulations of a theoretical model and a simple model. Due to the limited biomass and the thin litter layer, some sensitivity to variations of soil moisture is observed. Simulations of the theoretical model are in general agreement with measurements, with an...
Land emissivity is a key boundary condition particularly when used in Numerical Weather Prediction (NWP) models. The objective of this study is to develop a global land emissivity product using AMSR-E passive microwave data. This work investigates the impact of the difference in penetration depths between passive microwave and thermal temperatures on the retrieval of land emissivity. AMSR-E frequencies...
L-band radiometry is a technology that is able to provide physical information of the (sub) surface and the last forty years this unique feature has lead to numerous research studies. These studies were primarily focused on soil moisture retrieval from natural environments. However, the capacity of L-band Radiometry to provide us information about the subsurface of non natural environments, like man-made...
Modeling of snow emission at microwave frequencies is necessary in order to understand the relationships between the emitted brightness temperature and snowpack characteristics. Several empirical, semi-empirical and purely theoretical models for this purpose have been developed in recent years. This study compares the performance of two widely used semi-empirical models against experimental datasets...
A new microwave radiometric ocean surface emissivity model has been developed to support the analysis and design of the new airborne Hurricane Imaging Radiometer, HIRAD. This radiative transfer model extends current ocean surface emissivity capabilities to higher wind speeds and incidence angles. This model utilizes a variety of empirical data sources many of which were collected in hurricanes.
A combined multifactor hydrodynamic-electromagnetic model for ocean remote sensing is considered. We are focusing on microwave contributions from environmental factors: surface roughness, foam/whitecap, subsurface bubbles, and spray, and their joint impacts on ocean emissivity. This paper has presented a sketch of our numerical data related to L-band (1.4 GHz). In particular, we compute so-called...
Sea Surface Salinity (SSS) is a very important océanographie parameter that can be measured using L-band microwave radiometry. The measured brightness temperature measured over the ocean is influenced by the sea state that can even mask the salinity signature. Reflectometry using navigation signals (GNSS-R) has been proven to achieve sea state determination and has been proposed to be used to correct...
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