In the December 2006 severe forest fires raged in south east Australia. We used the OMI instrument to study the
transport of the aerosols emitted by these fires. On 14 December a freshly released plume was lofted by a passing
weather system to high altitudes in the atmosphere and was transported around the planet in 10 days. We used the OMI
cloud product to retrieve the altitude of the aerosol plume, 8-10km. We compare our findings to CALIPSO observations
of the same plume, which yields 11-14km. We performed radiative transfer calculations to investigate the sensitivity of
the OMI cloud algorithm to the plume altitude.
The detection and avoidance of external hazards is an important aspect of overall efforts to improve the safety of future
aircraft. Advanced sensor concepts may enhance the detection and quantification of risk due to external hazards. Such
sensors, when integrated into cockpit operations, may substantially improve vehicle safety. This paper will describe
research efforts to develop a simulation environment to evaluated advanced microwave sensor concepts such as airborne
bistatic radars utilizing multiple non-cooperative illuminators or emitters-of-opportunity to detect weather hazards, area
traffic, runway incursions, or other potential aircraft hazards.
We will present initial efforts to develop a flexible microwave sensor simulation and assessment tool. This tool will be
developed to assess the feasibility of various sensor concepts. Existing and potential future capability of the simulation
environment will be described. In addition, the results of the application of the simulation tool to a bistatic sensor
concept will be presented.
The Multi-angle Imaging SpectroRadiometer (MISR) has been acquiring global cloud and aerosol data from polar orbit
since February 2000. MISR acquires moderately high-resolution imagery at nine view angles from nadir to 70.5°, in four
visible/near-infrared spectral bands. Stereoscopic parallax, time lapse among the nine views, and the variation of
radiance with angle and wavelength enable retrieval of geometric cloud and aerosol plume heights, height-resolved
cloud-tracked winds, and aerosol optical depth and particle property information. Two instrument concepts based upon
MISR heritage are in development. The Cloud Motion Vector Camera, or WindCam, is a simplified version comprised
of a lightweight, compact, wide-angle camera to acquire multiangle stereo imagery at a single visible wavelength. A
constellation of three WindCam instruments in polar Earth orbit would obtain height-resolved cloud-motion winds with
daily global coverage, making it a low-cost complement to a spaceborne lidar wind measurement system. The
Multiangle SpectroPolarimetric Imager (MSPI) is aimed at aerosol and cloud microphysical properties, and is a
candidate for the National Research Council Decadal Survey's Aerosol-Cloud-Ecosystem (ACE) mission. MSPI
combines the capabilities of MISR with those of other aerosol sensors, extending the spectral coverage to the ultraviolet
and shortwave infrared and incorporating high-accuracy polarimetric imaging. Based on requirements for the nonimaging
Aerosol Polarimeter Sensor on NASA's Glory mission, a degree of linear polarization uncertainty of 0.5% is
specified within a subset of the MSPI bands. We are developing a polarization imaging approach using photoelastic
modulators (PEMs) to accomplish this objective.
The Ozone Monitoring Instrument (OMI) is first-of-its-kind hyperspectral instrument that employs two dimensional
UV-enhanced CCD's to measure radiation backscattered by the Earth's atmosphere from 270-500 nm at high spectral
resolution (0.45-0.63 nm), and with higher spatial resolution compared to the predecessor instruments (TOMS, SBUV,
GOME, and SCIAMACHY). OMI is a Dutch-Finnish contribution to the NASA EOS Aura satellite, which was
launched on 15 July 2004. The hyperspectral capability of OMI allows one to measure several trace gases in the
boundary layer (NO<sub>2</sub>, SO<sub>2</sub>, HCHO, BrO) at urban scale resolution. In addition, OMI continues the 28-year record of
data collected by the TOMS-series of instruments since Nov 1978, and SBUV-series of instruments since April 1970.
These products include ozone profile, total column ozone, tropospheric column ozone, volcanic SO<sub>2</sub>, and daily global
maps of UV-absorbing aerosols. In this paper we discuss recent results from OMI, focusing on OMI products related to
air quality over the Asian-Pacific region. OMI has the unique capability of seeing transport of dust and smoke above
clouds. Recent refinements to the algorithm are providing estimate of aerosol absorption, important for estimating the
solar radiation reaching the ground.
In 2006, we began a three-year project funded by the NASA Integrated Decisions Support program to develop a three-dimensional air quality system (3D-AQS). The focus of 3D-AQS is on the integration of aerosol-related NASA Earth Science Data into key air quality decision support systems used for air quality management, forecasting, and public health tracking. These will include the U.S. Environmental Protection Agency (EPA)'s Air Quality System/AirQuest and AIRNow, Infusing satellite Data into Environmental Applications (IDEA) product, U.S. Air Quality weblog (Smog Blog) and the Regional East Atmospheric Lidar Mesonet (REALM). The project will result in greater accessibility of satellite and lidar datasets that, when used in conjunction with the ground-based particulate matter monitors, will enable monitoring across horizontal and vertical dimensions. Monitoring in multiple dimensions will enhance the air quality community's ability to monitor and forecast the geospatial extent and transboundary transport of air pollutants, particularly fine particulate matter. This paper describes the concept of this multisensor system and gives current examples of the types of products that will result from it.
The column optical thickness of the atmospheric aerosol load is routinely retrieved using space borne measurements of the natural levels of upwelling shortwave radiation at the top of the atmosphere. The information content of the measurements includes contributions from several components of the earth-atmosphere system: the scattering and absorption processes of the molecular atmosphere (i.e., Rayleigh scattering and gas absorption), the scattering and absorption of aerosol particles, as well as the reflection from clouds and the underlying surface. The relative contribution from each component is a strong function of the wavelength of the incident radiation. Generally, the aerosol contribution is a very small fraction of the measurement. Therefore, as a part of the retrieval process, corrections for non-aerosol effects need to be applied to isolate the net aerosol effect.
GPS signals reflected from the ocean surface have been used in remote sensing applications to determine sea-state and wind speed. Studies show that, with rougher surfaces, GPS signal pulses scatter more, which creates weaker and wider pulses at the receiver. Based on this model, the correlation between soil moisture, topography, and GPS signals was studied using reflections off the ground. The data used for the study were gathered during two flights in 1998 and 2001 around Austin, Texas and Albuquerque, New Mexico and later processed at Langley Research Center. The power of the signals were analyzed and plotted over Digital Elevation Models (DEMs) and Landsat7 images (near- and mid-infrared bands) to interpret the correlation of signal behavior with topography. In addition, the received signal's conduct was correlated with soil moisture data obtained from the Department of Agriculture's Soil Climate Analysis Network (SCAN) sites at Prairie View (Texas) and Adams Ranch (New Mexico). The strengths of the reflected signals were observed larger near known bodies of water and farmlands where soil moisture levels are known to be high. In general, for flat lands, the power of the signals and soil moisture contents appeared to have a close-to-linear relationship. In addition, the received pulses widened when reflected over rapid-changing topography in Texas, but any relationship among these was not perceived in New Mexico. Further studies are needed to obtain a definite relationship among soil moisture and reflected signal strength and to introduce satellite position in the signal-topography study.