The NASA Earth Observing System Simulators Suite (NEOS3) is a modular framework of forward simulations tools for remote sensing of Earth’s Atmosphere from space. It was initiated as the Instrument Simulator Suite for Atmospheric
Remote Sensing (ISSARS) under the NASA Advanced Information Systems Technology (AIST) program of the Earth
Science Technology Office (ESTO) to enable science users to perform simulations based on advanced atmospheric and
simple land surface models, and to rapidly integrate in a broad framework any experimental or innovative tools that they
may have developed in this context. The name was changed to NEOS3 when the project was expanded to include more advanced modeling tools for the surface contributions, accounting for scattering and emission properties of layered
surface (e.g., soil moisture, vegetation, snow and ice, subsurface layers). NEOS3 relies on a web-based graphic user
interface, and a three-stage processing strategy to generate simulated measurements. The user has full control over a
wide range of customizations both in terms of a priori assumptions and in terms of specific solvers or models used to
calculate the measured signals.This presentation will demonstrate the general architecture, the configuration procedures
and illustrate some sample products and the fundamental interface requirements for modules candidate for integration.
KEYWORDS: Surface roughness, Reflectivity, Dielectric polarization, Data modeling, Monte Carlo methods, Soil science, Polarization, Correlation function, 3D modeling, L band
Soil moisture is an important parameter for hydrological and climatic investigations. Future satellite missions with L-band passive microwave radiometers will significantly increase the capability of monitoring Earth's soil moisture globally. Understanding the effects of surface roughness on microwave emission and developing quantitative bare surface soil moisture retrieval algorithms is one of the essential components in many applications of geophysical properties in the complex earth terrain by microwave remote sensing. In this study, we explore the use of the Integral Equation Model (IEM) for modeling microwave emission. This model was validated using a three-dimensional Monte Carlo model. The results indicate that the IEM model can be used to simulate the surface emission quite well for a wide range of surface roughness conditions with high confidence. Several important characteristics of the effects of surface roughness on radiometer emission signals at L-band 1.4 GHz that have not been adequately addressed in the current semi-empirical surface effective reflectivity models are demonstrated by using IEM simulated data. Using an IEM simulated database for a wide range of surface soil moisture and roughness properties, we developed a parameterized surface effective reflectivity model with three typically used correlation functions.
Broadband electromagnetic induction (EMI) methods are promising in the detection and discrimination of subsurface metallic targets. We compute EMI responses from conducting and permeable spheroids by using a field expansion method which is based on the separation of variables in spheroidal coordinates. In addition to an exact formulation which utilizes the vector spheroidal wavefunctions inside the spheroid, we also develop an approximate theory known as the small penetration-depth approximation (SPA). For general permeability, SPA is applicable at high frequency and compliments the exact formulation which breaks down at high frequency. However, when the permeability of the spheroid is large enough, the SPA yields an accurate broadband response. Numerical results for the far-field frequency responses from prolate and oblate spheroids are presented. By neglecting mutual interactions between the spheroids, we also study the broadband EMI response from a collection of spheroids that are randomly oriented and have different sizes.
We have found that highly efficient waveform recall is possible in coherent transient systems in which the storage is optically thick. Coherent transients may be used in a variety of information storage and processing applications with advantages over traditional electronic methods. However, it is believed that a serious problem in application of photon echoes in practical systems is the relatively low efficiency of the process. We show in our numerical studies that waveform recall efficiencies greater than unity can be achieved in absorbing media with appropriate choice of absorption length and brief pulse area, even for very weak data pulses. We also present our preliminary experimental results in Barium vapor in which efficiencies of 50% were obtained for both the stimulated and two-pulse photon echoes.
In a dense medium, the particles do not scatter independently. The effects of correlated scattering become important, and the spatial correlations of particles have to be included [1-5]. These have been verified in controlled laboratory experiments [3,4]. Propagation and scattering in dense media have been studied with the quasicrystalline approximation [2], and the quasicrystalline approximation with coherent potential for the first moment of the field [1] and the correlated ladder approximation for the second moment of the field [6]. The dense medium radiative transfer theory has also been developed from these approximations to study multiple scattering effects in dense media [6-8]. We have recently extended the results to medium to high frequencies and included the effects of Mie scattering from correlated scatterers of multiple sizes [9]. As a function of frequency, scattering first increases rapidly in the Rayleigh regime, then starts to level off at the Mie scattering regime. Comparisons have been made with experimental data of snow.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.