A5001876813- Atmospheric aerosols and clouds
- Atmospheric and Environmental Gas Dynamics
- Atmospheric Ozone and Climate
- Atmospheric chemistry and aerosols
- Arctic and Antarctic ice dynamics
- Calibration and Measurement Techniques
- Meteorological Phenomena and Simulations
- Cryospheric studies and observations
- Climate variability and models
- Solar Radiation and Photovoltaics
- Oceanographic and Atmospheric Processes
- Methane Hydrates and Related Phenomena
- Climate change and permafrost
- Marine and coastal ecosystems
- Earthquake Detection and Analysis
- Radiative Heat Transfer Studies
- Urban Heat Island Mitigation
- Ocean Acidification Effects and Responses
- Remote Sensing and LiDAR Applications
- Impact of Light on Environment and Health
- Graphite, nuclear technology, radiation studies
- Image Enhancement Techniques
- Computer Graphics and Visualization Techniques
- Digital Radiography and Breast Imaging
- Video Surveillance and Tracking Methods
Goddard Institute for Space Studies
2019-2024
Langley Research Center
2005-2021
Science Systems and Applications (United States)
2008-2016
Anhui Institute of Optics and Fine Mechanics
2016
Science and Technology Corporation (United States)
2013
Analytical Services & Materials (United States)
2002-2010
Support Systems Associates (United States)
2010
Scripps Institution of Oceanography
1999-2001
University of California, San Diego
1999-2000
University of Alaska Fairbanks
1992-1995
Seven models for computing underwater radiances and irradiances by numerical solution of the radiative transfer equation are compared. The applied to several problems drawn from optical oceanography. include highly absorbing scattering waters, molecules particulates, stratified water, atmospheric effects, surface-wave bottom Raman scattering. provide consistent output, with errors (resulting Monte Carlo statistical fluctuations) in computed that seldom larger, usually smaller, than...
The Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission will provide a calibration laboratory in orbit for the purpose of accurately measuring attributing climate change. CLARREO measurements establish new change benchmarks with high absolute radiometric accuracy statistical confidence across wide range essential variables. CLARREO's inherently be verified traceable on to Système Internationale (SI) units. established by critical assessing changes Earth system model...
The Edition 2 (Ed2) cloud property retrieval algorithm system was upgraded and applied to the MODerate-resolution Imaging Spectroradiometer (MODIS) data for Clouds Earth's Radiant Energy System (CERES) 4 (Ed4) products. New calibrations solar channels use of 1.24-μm channel optical depth (COD) over snow improve daytime consistency between Terra Aqua MODIS retrievals. Use additional spectral revised logic enhanced cloud-top phase accuracy. A new ice crystal reflectance model a CO <sub...
Measurements at a sea platform show that the ocean surface albedo is highly variable and sensitive to four physical parameters: solar zenith angle, wind speed, transmission by atmospheric cloud/aerosol, chlorophyll concentration. Using validated coupled ocean‐atmosphere radiative transfer model, an look up table created in terms of these important parameters. A code read also provided; it gives spectral albedos for range oceanic conditions specified user. The result fast accurate...
We have applied the discrete-ordinate method to solve radiative-transfer problem pertaining a system consisting of two strata with different indices refraction. The refraction and reflection at interface are taken into account. relevant changes (as compared standard constant index throughout medium) in formulation solution equation, including proper application boundary conditions, described. Appropriate quadrature points (streams) weights chosen for interface-continuity relations. Examples...
We present results from Phase I of the Continual Intercomparison Radiation Codes (CIRC), intended as an evolving and regularly updated reference source for evaluation radiative transfer (RT) codes used in global climate models other atmospheric applications. CIRC differs previous intercomparisons that it relies on observationally validated catalog cases. The seven baseline cases, five cloud free two with overcast liquid clouds, are built around observations by Atmospheric Measurements...
The Clouds and Earth's Radiant Energy System (CERES) has been monitoring clouds radiation since 2000 using algorithms developed before 2002 for CERES Edition 2 (Ed2) products. To improve cloud amount accuracy, 4 (Ed4) applies revised input data to Terra Aqua MODerate-resolution Imaging Spectroradiometer (MODIS) radiances. Ed4 mask uses 5-7 additional channels, new models clear-sky ocean snow/ice-surface radiances, MODIS calibrations. Mean daytime nighttime amounts exceed their Ed2...
Using the computationally efficient discrete-ordinate method, we present an analytical solution for radiative transfer in coupled atmosphere-ocean system with a rough air-water interface. The theoretical formulations of equation and are described. effects surface roughness on radiation field atmosphere ocean studied compared satellite measurements. results show that has significant upwelling downwelling ocean. As wind speed increases, angular domain sunglint broadens, albedo decreases,...
A simple yet accurate parameterization of spectral and broadband ocean surface albedo has been developed. To facilitate the its applications, is parameterized for direct diffuse incident radiation separately, then each them further divided into two components: contributions from water, respectively. The four components are independent other, hence, altering one will not affect others. Such a designed scheme flexible any future update. Users can simply replace adopted empirical formulations...
A multiple-stream radiative transfer scheme for sea ice suitable GCM applications is introduced. The algorithm explicitly considers the refraction at air-ice and air-water interfaces multiple scattering by inclusions entrapped in ice, such as brine pockets air bubbles. integrated volumes are derived from physical properties (salinity, density temperature) based on phase equilibrium relationships. Thus, optical represented a function of its properties, which used input variables computations....
A coupled one‐dimensional multilayer and multistream radiative transfer model has been developed applied to the study of interactions in atmosphere, sea ice, ocean system. The consistent solution equation this system automatically takes into account refraction reflection at air‐ice interface allows flexibility choice stream numbers. solar radiation spectrum (0.25 μm‐4.0 μm) is divided 24 spectral bands adequately for gaseous absorption atmosphere. effects ice property changes, including...
Abstract Studying aerosols over ocean is one goal of the Multiangle Imaging Spectroradiometer (MISR) and other spaceborne imaging systems. But top-of-atmosphere equivalent reflectance typically falls in range 0.03 to 0.12 at midvisible wavelengths can be below 0.01 near-infrared, when an optically thin aerosol layer viewed a dark surface. Special attention must given radiometric calibration if optical thickness, any information about particle microphysical properties, are reliably retrieved...
A fast and accurate principal component-based radiative transfer model in the solar spectral region (PCRTM-SOLAR) has been developed. The algorithm is capable of simulating reflected spectra both clear sky cloudy atmospheric conditions. Multiple scattering beam by multilayer clouds aerosols are calculated using a discrete ordinate scheme. PCRTM-SOLAR can be trained to simulate top-of-atmosphere radiance or reflectance with resolution ranging from 1 cm-1 few nanometers. Broadband radiances...
A coupled atmosphere–ocean radiative transfer model has been applied to analyze a full year of broadband solar irradiances (up and down) measured over an ocean site 25 km east the coast Virginia in Atlantic. The treats absorption scattering by layers for both atmosphere explicitly consistently. Key input parameters (aerosol optical depth, wind speed, total precipitable water) are also from situ measurements. Having more observations specify properties than ocean, better model–observation...
Relatively little work on cloud shadow detection has been published and many of these papers deal with restricted geometries. Here, arbitrary viewing illumination conditions are considered. A means is provided to extend more treatments removal the general case.
The bidirectional reflectance anisotropy in Advanced Very High Resolution Radiometer (AVHRR) Channel 1 and 2 spectral regions for snow- ice-covered surfaces was investigated using a comprehensive radiative transfer model the coupled atmosphere, snow, ice, ocean system. has been developed to include surface roughness effects. importance of scattering characteristics snow sea ice these is presented. modeled anisotropic factor, however, shows less sensitivity aerosol loading soot contamination...
One of the Climate Absolute Radiance and Refractivity Observatory (CLARREO) mission objectives is to provide a high accuracy calibration standard on orbit enable inter-calibration existing sensors. In order perform an accurate imaging radiometers, such as VIIRS, one must take into account instrument sensitivity polarization incoming light. Even if established or known orbit, knowledge state reflected light required make relevant radiometric corrections. case when coincident polarimetric...
Abstract. Climate warming has a stronger impact on Arctic climate and sea ice cover (SIC) decline than previously thought. Better understanding characterization of the relationship between clouds implications for surface radiation is key to improving our confidence in projections. Here we analyze ice, cloud phase over Arctic, defined as north 60° N, using active- passive-sensor satellite observations from three different datasets. We find that all datasets agree climatology seasonal...
Spectral measurements of biologically relevant radiation at McMurdo Station, Antarctica reveal ultraviolet (UV) irradiance levels 305 nm in October exceeding by a factor between 3 and 6 “normal” values expected for undepleted ozone levels. This enhancement is directly related to the depletion. The column abundance stratospheric derived from these was as low 145 Dobson Units (DU) October, 1990. more than 2 lower value solstice, 100 DU less 1988. dose rate damage DNA molecule based on Setlow's...
Abstract This study aims to create observation‐based cloud radiative kernel (CRK) datasets and evaluate them by direct comparison of CRK the CRK‐derived feedback datasets. Based on International Satellite Cloud Climatology Project (ISCCP) H datasets, we calculate CRKs (called ISCCP‐FH or FH CRKs) as 2D joint function/histogram optical depth top pressure for shortwave (SW), longwave (LW), their sum, Net, at atmosphere (TOA), well as, first time, surface (SFC) in (ATM). With fraction change...
[1] The radiative kernel approach provides a simple way to separate the response different climate parameters and decompose feedback into components. Using CERES/MODIS/Geostationary data, we calculated analyzed solar spectral reflectance kernels for various on zonal, regional, global spatial scales. linearity is tested. Errors in due nonlinearity can vary strongly depending parameter, wavelength, surface, elevation; they are large some absorption bands but negligible most conditions. used...