Lisa Huddleston, William Roeder, David Morabito, Larry D'Addario, Jennifer Morgan, Robert Barbré, Ryan Decker, Barry Geldzahler, Mark Seibert, Michael Miller
This paper provides an overview of ground based operational remote sensing activities that enable a broad range of missions at the Eastern Range (ER), which includes the National Aeronautics and Space Administration (NASA) Kennedy Space Center (KSC) and U.S. Air Force Cape Canaveral Air Force Station (CCAFS). Many types of sensors are in use by KSC and across the ER. We examine remote sensors for winds, lightning and electric fields, precipitation and storm hazards. These sensors provide data that are used in real-time to evaluate launch commit criteria during space launches, major ground processing operations in preparation for space launches, issuing weather warnings/watches/advisories to protect over 25,000 people and facilities worth over $20 billion, and routine weather forecasts. The data from these sensors are archived to focus NASA launch vehicle design studies, to develop forecast techniques, and for incident investigation. The wind sensors include the 50-MHz and 915-MHz Doppler Radar Wind Profilers (DRWP) and the Doppler capability of the weather surveillance radars. The atmospheric electricity sensors include lightning aloft detectors, cloud-to-ground lightning detectors, and surface electric field mills. The precipitation and storm hazards sensors include weather surveillance radars. Next, we discuss a new type of remote sensor that may lead to better tracking of near-Earth asteroids versus current capabilities. The Ka Band Objects Observation and Monitoring (KaBOOM) is a phased array of three 12 meter (m) antennas being built as a technology demonstration for a future radar system that could be used to track deep-space objects such as asteroids. Transmissions in the Ka band allow for wider bandwidth than at lower frequencies, but the signals are also far more susceptible to de-correlation from turbulence in the troposphere, as well as attenuation due to water vapor, which is plentiful in the Central Florida atmosphere. If successful, KaBOOM will have served as the pathfinder for a larger and more capable instrument that will enable tracking 15 m asteroids up to 72 million kilometers (km) away, about half the distance to the Sun and five times further than we can track today. Finally, we explore the use of Site Test Interferometers (STI) as atmospheric sensors. The STI antennas continually observe signals emitted by geostationary satellites and produce measurements of the phase difference between the received signals. STIs are usually located near existing or candidate antenna array sites to statistically characterize atmospheric phase delay fluctuation effects for the site. An STI measures the fluctuations in the difference of atmospheric delay from an extraterrestrial source to two or more points on the Earth. There is a three-element STI located at the KaBOOM site at KSC.
KEYWORDS: Monte Carlo methods, 3D modeling, Photons, Remote sensing, Atmospheric modeling, Shape analysis, 3D image processing, Water, Scattering, Reflectivity
This paper describes the results of modeling the water wave surface and underwater light field as influenced by water
waves using a Monte Carlo model (MCHSIM). Model and sensor data related to water column properties and benthic
properties that influence the light upwelled from below the water - as observed from a sensor looking from below or
above the water surface is presented. Synthetic image results using Monte Carlo techniques show the influence of water
waves upon subsurface shape factors and these factors can be used in shallow water remote sensing algorithms that are
based on underlying analytical models. The upwelling angular distribution of light is calculated from the model and
results shown for 490 nm. The upwelling and downwelling shape factors are shown from model runs which compare the
results with solar zenith angle for nadir viewing geometry, and for realistic water surface wave facets. It is clearly shown
that shape factors are strongly dependent upon not only viewing geometry and zenith angle of the sun, but also upon
water waves that can focus and defocus radiance entering a wind roughened water column and influence the shape
factors due to the scattering lobe effect. This paper presents results quantifying the magnitude of water effects upon the
upwelling and downwelling shape factors in a systematic and quantifiable manner at 490 nm and demonstrates the utility
of the model to assess the influence of water waves in a full 3-D Monte Carlo hyperspectral synthetic image cube model
that accounts for adjacency effects.
A sensitivity analysis of the irradiance reflectance calculated from the modified two-flow equations (Bostater, et al., and
Bostater et al, 2002) to various model inputs is addressed. The modified two-flow equation approximate of the radiative
transfer equation (RTE) with a collimated or specular component is used to calculate the sensitivity of the calculated
irradiance reflectance on the inclusion of solar zenith angle, wind speed, shape factors, chlorophyll-a concentration,
water depth, and bottom type.
A pushbroom sensor motion control system was developed for use in conjunction with a pulsed laser fan beam, streak tube camera, and a high speed low light level camera . The LIDAR and camera control system was tested to study the influence of water waves upon active-passive remote sensing systems and associated models that require pushbroom sensor motion. A pulsed laser fan beam signal at 532 nm was recorded using a streak tube camera and a (high speed, low light level, high quantum efficiency) digital CCD camera. Tests were conducted in 3 different water tanks, including 2 tanks with water waves (the longest wave tank or channel is 60 m long). Capillary waves, ~1 cm wavelength) were generated using an acoustic wave source generator. Streak tube camera and CCD images were collected in conjunction with a 532 nm pico-second short pulse laser. Images collected demonstrate the pulse stretching around submerged water
targets as well as the ability to discriminate water depth of submerged targets in shallow water types. In turbid water, the
pulsed layer backscatter structure showed a nearly random return as a function of depth if the signal was attenuated before reaching the bottom of the water column. The data collected indicated the motion control testing system can accommodate a variety of cameras and instruments in the lab and in the outdoor water wave channel. Data from these camera systems are being used to help validate analytical and Monte Carlo models of the water surface structure, and the
underwater light field structure (pulse stretching) as well as to validate other LIDAR applications used in bathymetric and hydrographic surveys of coastal waters and marine inlets for physical and biological (submerged vegetation) surveys.
The purpose of this paper is to present results of simulations of the Florida Tech UTC-M sea-breeze model with the addition of a simplified atmospheric downwelling radiation subroutine combined and a thermal inertia subroutine into the atmospheric planetary boundary layer model, in order to calculate time dependant heat flux boundary conditions at the air-land boundary that are derived from
satellite data from AVHRR and MODIS sensors. The improved UTC-M planetary boundary layer model with this thermal sub-model subroutine is used to demonstrate the use of thermal inertia to help estimate
heat fluxes at the land-air interface which in turn influences convergence and vertical fluxes near the bottom boundary, and which may affect mesoscale meteorological wind and seabreeze over complex
land-water margins. Additionally, message passage interface (MPI) parallelizing Fortran techniques were used to improve the computational time when the model grid was decreased down to 2 or 1 km cell when simulations where performed on the FIT supercomputer based on an IBM Beowulf Linux cluster. We present some results of the UTC-M simulations and associated results due to the influence of the
parameterization of the net surface radiation and thermal inertia using the spectral or wavelength (channel) specific data from MODIS and AVHRR satellite sensors.
Modeled hyperspectral reflectance signatures just above the water surface are obtained from an analytical radiative transport model applicable to shallow water types. Light transport within the water body is simulated using a fast, accurate radiative transfer model that calculates the light distribution in any layered media. A realistic water surface is synthesized using empirically-based statistical models of ocean surface waves. Images are displayed as 24 bit RGB images of the water surface using selected channels. The selected channels are centered at 480, 520 and 650 nm. Hyperspectral image cubes with two spatial and a third spectral dimension are shown to allow the detection of any optically unresolved features in the two-dimensional RGB image.
Modeled hyperspectral reflectance signatures just above the water surface are obtained from radiative transfer models to create synthetic images of the water surface. Images are displayed as 24 bit RGB images of the water surface using selected channel. Comparisons are made in this paper between a hyperspectral Monte Carlo and a hyperspectral layered analytical model of radiative transport applicable to shallow water types. Images at the selected wavelengths or channels centered at 490, 530 and 680 nm suggest the two models provide the same results when displayed as RGB images. The most sensitive parameters for generating realistic images are water depth and bottom reflectance in clean natural, optically shallow waters. The images clearly demonstrate the need importance of detailed and accurate water depths.
This paper describes the radiative transfer of the sun’s electromagnetic energy utilizing a solution to the two-flow irradiance equations that generates fast and accurate estimates of light distributions in any layered media, such as water with depth dependent concentrations of water column constituents. The layered model is designed to generate synthetic water surface reflectance signatures and associated synthetic images, in the presence of depth dependent water constituents, various bottom types, and variable water depths. The layered model accounts for specular (collimated) irradiance below the water’s surface and utilizes boundary conditions that allow the absorption, backscatter, beam attenuation, and conversion (from specular irradiance to diffuse irradiance) coefficients to vary as a function of depth. In addition, the model allows one to compute the influences of submerged targets, bottom types or unique submerged targets or water column layers with defined by their reflectance signatures of unique absorption and backscatter characteristics. Model simulations are presented to demonstrate the utility of the model for development of remote sensing algorithms for use in coastal and marine water types.
The purpose of this paper is to present simulation results of a thermal sub-model developed for the Florida Tech UTC-M sea-breeze model. The insertion of this thermal radiative model into the atmospheric planetary boundary layer model, allows calculation of time dependant heat flux boundary conditions at the air-land boundary that are derived from satellite data such as AVHRR and MODIS. The improved UTC-M planetary boundary layer model with this thermal sub-model is used to demonstrate the use of thermal inertia to help estimate heat fluxes at the land-air interface which in turn influences convergence and vertical fluxes, which then affects mesoscale meteorological wind and convergence predictions. We present thermal radiative model simulations and associated results due to the influence of the parameterization of the net surface radiation and thermal inertia using wavelength or channel specific data from MODIS and AVHRR satellite sensors. Results are presented for cloudless sky conditions.
In this paper we conduct sensitivity analyses of the land surface boundary conditions and parameterizations in the UTC-M primitive equation atmospheric planetary boundary layer Seabreeze model. The boundary conditions for temperature of the ocean and land surface is based upon satellite derived AVHRR estimates over the water and coastal land margins. The sensitivity analysis of the boundary conditions as well as the heating and cooling rates in the planetary boundary layer model are also described. The model domain of interest is the region over the Space Coats of Central Florida. This reign is unique because of its complex coastal water-land margin and its close proximity to the Gulf Stream and Cape Canaveral. This model study demonstrates a method whereby the ocean surface and atmosphere is couple using remotely sensed data for predicting the coastal Seabreeze and associated convective convergence and expected cloud development in the planetary boundary layer.
This paper compares homogeneous analytical two-flow equation solutions to an improved iterative solution technique of the same differential equations that describe the transfer of irradiance in a layered medium such as water with depth dependent water constituents. The layered model is developed to be used in oceanic or atmospheric models in order to provide a detailed mechanism for the influence of irradiant energy in the heating rate of the medium. The layered model is designed to generate synthetic water surface reflectance signatures in the presence of depth dependent water constituents, various bottom types, and variable water depths. In addition, the model allows one to compute the influences of submerged targets or layers with unique reflectance signatures or unique absorption and backscatter characteristics.
A remote sensing reflectance model, which describes the transfer of irradiant light within a homogeneous water column has previously been used to simulate the nadir viewing reflectance just above or below the water surface by Bostater, et al. Wavelength dependent features in the water surface reflectance depend upon the nature of the down welling irradiance, bottom reflectance and the water absorption and backscatter coefficients. The latter are very important coefficients, and depend upon the constituents in water and both vary as a function of the water depth and wavelength in actual water bodies. This paper describes a preliminary approach for the analytical solution of the radiative transfer equations in a two-stream representation of the irradiance field with variable coefficients due to the depth dependent water concentrations of substances such as chlorophyl pigments, dissolved organic matter and suspended particulate matter. The analytical model formulation makes use of analytically based solutions to the 2-flow equations. However, in this paper we describe the use of the unique Cauchy boundary conditions previously used, along with a matrix solution to allow for the prediction of the synthetic water surface reflectance signatures within a nonhomogeneous medium. Observed reflectance signatures as well as model derived 'synthetic signatures' are processed using efficient algorithms which demonstrate the error induced using the layered matrix approach is much less than 1 percent when compared to the analytical homogeneous water column solution. The influence of vertical gradients of water constituents may be extremely important in remote sensing of coastal water constituents as well as in remote sensing of submerged targets and different bottom types such as corals, sea grasses and sand.
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