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Cox S.J.,SSAI Inc. | Stackhouse P.W.,NASA | Gupta S.K.,SSAI Inc. | Mikovitz J.C.,SSAI Inc. | Zhang T.,SSAI Inc.
AIP Conference Proceedings | Year: 2017

The NASA/GEWEX Surface Radiation Budget (SRB) project produces shortwave and longwave surface and top of atmosphere radiative fluxes for the 1983-near present time period. Spatial resolution is 1 degree. The current Release 3.0 (available at gewex-srb.larc.nasa.gov) uses the International Satellite Cloud Climatology Project (ISCCP) DX product for pixel level radiance and cloud information. This product is subsampled to 30 km. ISCCP is currently recalibrating and recomputing their entire data series, to be released as the H product, at 10km resolution. The ninefold increase in pixel number will allow SRB a higher resolution gridded product (e.g. 0.5 degree), as well as the production of pixel-level fluxes. Other key input improvements include a detailed aerosol history using the Max Planck Institute Aerosol Climatology (MAC), and temperature and moisture profiles from nnHIRS. © 2017 Author(s).


News Article | May 4, 2017
Site: www.prnewswire.com

AdExchanger's Managing Editor Ryan Joe received the silver award for his work separating fact from fiction when it comes to artificial intelligence, while Ms. Liyakasa, senior editor of AdExchanger, was bestowed the bronze award for her work articulating the motives and implications of server-side ad insertion (SSAI).  As more TV content is being consumed across platforms, SSAI is emerging as a key method for video publishers to mitigate ad blocking and boost video playback across devices. AdExchanger readers include marketers, advertising agencies, publishers, data providers and technology companies.  The company helps its audience understand the increasingly complicated marketing ecosystem through unrivaled news reporting and illuminating thought leadership from industry experts.  It also brings readers and major players together at several conferences throughout the year across the United States. "I am delighted that Ryan and Kelly have received this recognition for their great reporting work from the American Society for Business Publication Editors (ASBPE)," said Zach Rodgers, Executive Editor of AdExchanger.  "They are both top notch, dedicated editors with detailed technical knowledge of their beats." The ASBPE announced the winners at the Northeast Regional Azbee Awards Banquet last night in New York City.  The awards honor all types of publications including magazines, newspapers, newsletters, websites and digital media.  National winners will be announced on May 18 in St. Petersburg, Fla. About AdExchanger Founded in 2008, AdExchanger is an award-winning integrated media company – which includes publishing and three large industry events devoted to the data-driven, digital marketing space.  The company produces Industry Preview, which provides an exclusive look at the year ahead in digital marketing technology, as well as two bi-coastal, leading conferences in programmatic media, known as PROGRAMMATIC I/O.  For more information, visit www.adexchanger.com. To view the original version on PR Newswire, visit:http://www.prnewswire.com/news-releases/adexchanger-journalists-receive-2017-azbee-awards-of-excellence-300451580.html


Fernandez J.R.,NASA | Mertens C.J.,NASA | Bilitza D.,George Mason University | Xu X.,SSAI Inc. | And 2 more authors.
Advances in Space Research | Year: 2010

We present a new technique for improving ionospheric models of nighttime E-region electron densities under geomagnetic storm conditions using TIMED/SABER measurements of broadband 4.3 μm limb radiance. The response of E-region electron densities to geomagnetic activity is characterized by SABER-derived NO+(v) 4.3 μm Volume Emission Rates (VER). A storm-time E-region electron density correction factor is defined as the ratio of storm-enhanced NO+(v) VER to a quiet-time climatological average NO+(v) VER, which will be fit to a geomagnetic activity index in a future work. The purpose of this paper is to demonstrate the feasibility of our technique in two ways. One, we compare storm-to-quiet ratios of SABER-derived NO+(v) VER with storm-to-quiet ratios of electron densities measured by Incoherent Scatter Radar. Two, we demonstrate that NO+(v) VER can be parameterized by widely available geomagnetic activity indices. The storm-time correction derived from NO+(v) VER is applicable at high-latitudes. © 2010 COSPAR. Published by Elsevier Ltd. All rights reserved.


Wind G.,NASA | Wind G.,SSAI Inc. | Da Silva A.M.,NASA | Norris P.M.,NASA | And 2 more authors.
Geoscientific Model Development | Year: 2013

In this paper we describe a general procedure for calculating synthetic sensor radiances from variable output from a global atmospheric forecast model. In order to take proper account of the discrepancies between model resolution and sensor footprint, the algorithm takes explicit account of the model subgrid variability, in particular its description of the probability density function of total water (vapor and cloud condensate.) The simulated sensor radiances are then substituted into an operational remote sensing algorithm processing chain to produce a variety of remote sensing products that would normally be produced from actual sensor output. This output can then be used for a wide variety of purposes such as model parameter verification, remote sensing algorithm validation, testing of new retrieval methods and future sensor studies. We show a specific implementation using the GEOS-5 model, the MODIS instrument and the MODIS Adaptive Processing System (MODAPS) Data Collection 5.1 operational remote sensing cloud algorithm processing chain (including the cloud mask, cloud top properties and cloud optical and microphysical properties products). We focus on clouds because they are very important to model development and improvement. © Author(s) 2013.


Wind G.,NASA | Wind G.,SSAI Inc. | Platnick S.,NASA | King M.D.,University of Colorado at Boulder | And 6 more authors.
Journal of Applied Meteorology and Climatology | Year: 2010

Data Collection 5 processing for the Moderate Resolution Imaging Spectroradiometer (MODIS) on board the NASA Earth Observing System (EOS) Terra and Aqua spacecraft includes an algorithm for detecting multilayered clouds in daytime. The main objective of this algorithm is to detect multilayered cloud scenes, specifically optically thin ice cloud overlying a lower-level water cloud, that present difficulties for retrieving cloud effective radius using single-layer plane-parallel cloud models. The algorithm uses the MODIS 0.94-μm water vapor band along with CO 2 bands to obtain two above-cloud precipitable water retrievals, the difference of which, in conjunction with additional tests, provides a map of where multilayered clouds might potentially exist. The presence of a multilayered cloud results in a large difference in retrievals of above-cloud properties between the CO 2 and the 0.94-mm methods. In this paper the MODIS multilayered cloud algorithm is described, results of using the algorithm over example scenes are shown, and global statistics for multilayered clouds as observed by MODIS are discussed. A theoretical study of the algorithm behavior for simulated multilayered clouds is also given. Results are compared to two other comparable passive imager methods. A set of standard cloudy atmospheric profiles developed during the course of this investigation is also presented. The results lead to the conclusion that the MODIS multilayer cloud detection algorithm has some skill in identifying multilayered clouds with different thermodynamic phases. © 2010 American Meteorological Society.


Dong X.,University of North Dakota | Xi B.,University of North Dakota | Qiu S.,University of North Dakota | Minnis P.,NASA | And 2 more authors.
Journal of Geophysical Research: Atmospheres | Year: 2016

Retrievals of cloud microphysical properties based on passive satellite imagery are especially difficult over snow-covered surfaces because of the bright and cold surface. To help quantify their uncertainties, single-layered overcast liquid-phase Arctic stratus cloud microphysical properties retrieved by using the Clouds and the Earth's Radiant Energy System Edition 2 and Edition 4 (CERES Ed2 and Ed4) algorithms are compared with ground-based retrievals at the Atmospheric Radiation Measurement North Slope of Alaska (ARM NSA) site at Barrow, AK, during the period from March 2000 to December 2006. A total of 206 and 140 snow-free cases (Rsfc ≤ 0.3), and 108 and 106 snow cases (Rsfc > 0.3), respectively, were selected from Terra and Aqua satellite passes over the ARM NSA site. The CERES Ed4 and Ed2 optical depth (τ) and liquid water path (LWP) retrievals from both Terra and Aqua are almost identical and have excellent agreement with ARM retrievals under snow-free and snow conditions. In order to reach a radiation closure study for both the surface and top of atmosphere (TOA) radiation budgets, the ARM precision spectral pyranometer-measured surface albedos were adjusted (63.6% and 80% of the ARM surface albedos for snow-free and snow cases, respectively) to account for the water and land components of the domain of 30 km × 30 km. Most of the radiative transfer model calculated SW↓ sfc and SW↑ TOA fluxes by using ARM and CERES cloud retrievals and the domain mean albedos as input agree with the ARM and CERES flux observations within 10 W m−2 for both snow-free and snow conditions. Sensitivity studies show that the ARM LWP and re retrievals are less dependent on solar zenith angle (SZA), but all retrieved optical depths increase with SZA. ©2016. American Geophysical Union. All Rights Reserved.


Wind G.,NASA | Wind G.,SSAI Inc. | Silva A.M.D.,NASA | Norris P.M.,NASA | And 5 more authors.
Geoscientific Model Development | Year: 2016

The Multi-sensor Cloud Retrieval Simulator (MCRS) produces a "simulated radiance" product from any high-resolution general circulation model with interactive aerosol as if a specific sensor such as the Moderate Resolution Imaging Spectroradiometer (MODIS) were viewing a combination of the atmospheric column and land-ocean surface at a specific location. Previously the MCRS code only included contributions from atmosphere and clouds in its radiance calculations and did not incorporate properties of aerosols. In this paper we added a new aerosol properties module to the MCRS code that allows users to insert a mixture of up to 15 different aerosol species in any of 36 vertical layers.This new MCRS code is now known as MCARS (Multi-sensor Cloud and Aerosol Retrieval Simulator). Inclusion of an aerosol module into MCARS not only allows for extensive, tightly controlled testing of various aspects of satellite operational cloud and aerosol properties retrieval algorithms, but also provides a platform for comparing cloud and aerosol models against satellite measurements. This kind of two-way platform can improve the efficacy of model parameterizations of measured satellite radiances, allowing the assessment of model skill consistently with the retrieval algorithm. The MCARS code provides dynamic controls for appearance of cloud and aerosol layers. Thereby detailed quantitative studies of the impacts of various atmospheric components can be controlled.In this paper we illustrate the operation of MCARS by deriving simulated radiances from various data field output by the Goddard Earth Observing System version 5 (GEOS-5) model. The model aerosol fields are prepared for translation to simulated radiance using the same model subgrid variability parameterizations as are used for cloud and atmospheric properties profiles, namely the ICA technique. After MCARS computes modeled sensor radiances equivalent to their observed counterparts, these radiances are presented as input to operational remote-sensing algorithms.Specifically, the MCARS-computed radiances are input into the processing chain used to produce the MODIS Data Collection 6 aerosol product (M{O/Y}D04). The M{O/Y}D04 product is of course normally produced from M{O/Y}D021KM MODIS Level-1B radiance product directly acquired by the MODIS instrument. MCARS matches the format and metadata of a M{O/Y}D021KM product. The resulting MCARS output can be directly provided to MODAPS (MODIS Adaptive Processing System) as input to various operational atmospheric retrieval algorithms. Thus the operational algorithms can be tested directly without needing to make any software changes to accommodate an alternative input source.We show direct application of this synthetic product in analysis of the performance of the MOD04 operational algorithm. We use biomass-burning case studies over Amazonia employed in a recent Working Group on Numerical Experimentation (WGNE)-sponsored study of aerosol impacts on numerical weather prediction (Freitas et al., 2015). We demonstrate that a known low bias in retrieved MODIS aerosol optical depth appears to be due to a disconnect between actual column relative humidity and the value assumed by the MODIS aerosol product. © 2016 Author(s).


Mast J.,SSAI Inc. | Mlynczak M.G.,NASA | Hunt L.A.,SSAI Inc. | Marshall B.T.,G and A Technical Software | And 4 more authors.
Geophysical Research Letters | Year: 2013

Absolute concentrations (cm-3) of highly vibrationally excited hydroxyl (OH) are derived from measurements of the volume emission rate of the ε = 9 + 8 states of the OH radical made by the SABER instrument on the TIMED satellite. SABER has exceptionally sensitive measurement precision that corresponds to an ability to detect changes in volume emission rate on the order of ~5 excited OH molecules per cm3. Peak zonal annual mean concentrations observed by SABER exceed 1000 cm-3 at night and 225 cm-3 during the day. Measurements since 2002 show an apparent altitude-dependent variation of the night OH(ε = 9 + 8) concentrations with the 11 year solar cycle, with concentrations decreasing below ~ 95 km from 2002 to 2008. These observations provide a global database for evaluating photochemical model computations of OH abundance, reaction kinetics, and rates and mechanisms responsible for maintaining vibrationally excited OH in the mesopause region. Key Points First measured absolute global concentrations of OH(9+8) in mesopause region Long term measurements give evidence of solar cycle variability of OH(v) Pertinent to photochemical models and measurement of reaction kinetics ©2013. American Geophysical Union. All Rights Reserved.


Pagaran J.,University of Bremen | Weber M.,University of Bremen | DeLand M.T.,Inc SSAI | Floyd L.E.,Interferometrics Inc. | Burrows J.P.,University of Bremen
Solar Physics | Year: 2011

Regular solar spectral irradiance (SSI) observations from space that simultaneously cover the UV, visible (vis), and the near-IR (NIR) spectral region began with SCIAMACHY aboard ENVISAT in August 2002. Up to now, these direct observations cover less than a decade. In order for these SSI measurements to be useful in assessing the role of the Sun in climate change, records covering more than an eleven-year solar cycle are required. By using our recently developed empirical SCIA proxy model, we reconstruct daily SSI values over several decades by using solar proxies scaled to short-term SCIAMACHY solar irradiance observations to describe decadal irradiance changes. These calculations are compared to existing solar data: the UV data from SUSIM/UARS, from the DeLand & Cebula satellite composite, and the SIP model (S2K+VUV2002); and UV-vis-IR data from the NRLSSI and SATIRE models, and SIM/SORCE measurements. The mean SSI of the latter models show good agreement (less than 5%) in the vis regions over three decades while larger disagreements (10 - 20%) are found in the UV and IR regions. Between minima and maxima of Solar Cycles 21, 22, and 23, the inferred SSI variability from the SCIA proxy is intermediate between SATIRE and NRLSSI in the UV. While the DeLand & Cebula composite provide the highest variability between solar minimum and maximum, the SIP/Solar2000 and NRLSSI models show minimum variability, which may be due to the use of a single proxy in the modeling of the irradiances. In the vis-IR spectral region, the SCIA proxy model reports lower values in the changes from solar maximum to minimum, which may be attributed to overestimations of the sunspot proxy used in modeling the SCIAMACHY irradiances. The fairly short timeseries of SIM/SORCE shows a steeper decreasing (increasing) trend in the UV (vis) than the other data during the descending phase of Solar Cycle 23. Though considered to be only provisional, the opposite trend seen in the visible SIM data challenges the validity of proxy-based linear extrapolation commonly used in reconstructing past irradiances. © 2011 Springer Science+Business Media B.V.


Markham B.L.,NASA | Haque M.O.,Eros | Barsi J.A.,SSAI Inc. | Micijevic E.,Eros | And 4 more authors.
IEEE Transactions on Geoscience and Remote Sensing | Year: 2012

The Landsat-7 ETM+ sensor has been operating on orbit for more than 12 years, and characterizations of its performance have been ongoing over this period. In general, the radiometric performance of the instrument has been remarkably stable: 1) noise performance has degraded by 2% or less overall, with a few detectors displaying step changes in noise of 2% or less; 2) coherent noise frequencies and magnitudes have generally been stable, though the within-scan amplitude variation of the 20 kHz noise in bands 1 and 8 disappeared with the failure of the scan line corrector and a new similar frequency noise (now about 18 kHz) has appeared in two detectors in band 5 and increased in magnitude with time; 3) bias stability has been better than 0.25 DN out of a normal value of 15 DN in high gain; 4) relative gains, the differences in response between the detectors in the band, have generally changed by 0.1% or less over the mission, with the exception of a few detectors with a step response change of 1% or less; and 5) gain stability averaged across all detectors in a band, which is related to the stability of the absolute calibration, has been more stable than the techniques used to measure it. Due to the inability to confirm changes in the gain (beyond a few detectors that have been corrected back to the band average), ETM+ reflective band data continues to be calibrated with the prelaunch measured gains. In the worst case, some bands may have changed as much as 2% in uncompensated absolute calibration over the 12 years. © 2012 IEEE.

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