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Articles 1 - 8 of 8
Full-Text Articles in Atmospheric Sciences
Global Validation Of Columnar Water Vapor Derived From Eos Modis-Maiac Algorithm Against The Ground-Based Aeronet Observations, Vitor S. Martins, Alexei Lyapustin, Yujie Wang, David M. Giles, Alexander Smirnov, Ilya Slutsker, Sergey Korkin
Global Validation Of Columnar Water Vapor Derived From Eos Modis-Maiac Algorithm Against The Ground-Based Aeronet Observations, Vitor S. Martins, Alexei Lyapustin, Yujie Wang, David M. Giles, Alexander Smirnov, Ilya Slutsker, Sergey Korkin
Vitor Martins
The water vapor is a relevant greenhouse gas in the Earth's climate system, and satellite products become one of the most effective way to characterize and monitor the columnar water vapor (CWV) content at global scale. Recently, a new product (MCD19) was released as part of MODIS (Moderate Resolution Imaging Spectroradiometer) Collection 6 (C6). This operational product from Multi-Angle Implementation for Atmospheric Correction (MAIAC) algorithm includes a high 1 km resolution CWV retrievals. This study presents the first global validation of MAIAC C6 CWV obtained from MODIS MCD19A2 product. This evaluation was performed using Aerosol Robotic Network (AERONET) observations at …
Validation Of High‐Resolution Maiac Aerosol Product Over South America, Vitor S. Martins, Alexei Lyapustin, Lino A.S. De Carvalho, Claudio C.F. Barbosa, Evlyn M.L.M. Novo
Validation Of High‐Resolution Maiac Aerosol Product Over South America, Vitor S. Martins, Alexei Lyapustin, Lino A.S. De Carvalho, Claudio C.F. Barbosa, Evlyn M.L.M. Novo
Vitor Martins
Moderate Resolution Imaging Spectroradiometer (MODIS) algorithm that combines time series approach and image processing to derive surface reflectance and atmosphere products, such as aerosol optical depth (AOD) and columnar water vapor (CWV). The quality assessment of MAIAC AOD at 1 km resolution is still lacking across South America. In the present study, critical assessment of MAIAC AOD550 was performed using ground‐truth data from 19 Aerosol Robotic Network (AERONET) sites over South America. Additionally, we validated the MAIAC CWV retrievals using the same AERONET sites. In general, MAIAC AOD Terra/Aqua retrievals show high agreement with ground‐based measurements, with a correlation coefficient …
Seasonal And Interannual Assessment Of Cloud Cover And Atmospheric Constituents Across The Amazon (2000–2015): Insights For Remote Sensing And Climate Analysis, Vitor S. Martins, Evlyn M.L.M. Novo, Alexei Lyapustin, Luiz E.O.C. Aragão, Saulo R. Freitas, Claudio C.F. Barbosa
Seasonal And Interannual Assessment Of Cloud Cover And Atmospheric Constituents Across The Amazon (2000–2015): Insights For Remote Sensing And Climate Analysis, Vitor S. Martins, Evlyn M.L.M. Novo, Alexei Lyapustin, Luiz E.O.C. Aragão, Saulo R. Freitas, Claudio C.F. Barbosa
Vitor Martins
The quantitative assessment of cloud cover and atmospheric constituents improves our ability to exploit the climate feedback into the Amazon basin. In the 21st century, three droughts have already occurred in the Amazonia (e.g. 2005, 2010, 2015), inducing regional changes in the seasonal patterns of atmospheric constituents. In addition to climate, the atmospheric dynamic and attenuation properties are long-term challenges for satellite-based remote sensing of this ecosystem: high cloudiness, abundant water vapor content and biomass burning season. Therefore, while climatology analysis supports the understanding of atmospheric variability and trends, it also offers valuable insights for remote sensing applications. In this …
Ionospheric Signatures Of Acoustic Waves Generated By Transient Tropospheric Forcing, M. D. Zettergren, J. B. Snively
Ionospheric Signatures Of Acoustic Waves Generated By Transient Tropospheric Forcing, M. D. Zettergren, J. B. Snively
Matthew David Zettergren
Acoustic waves generated by tropospheric sources may attain significant amplitudes in the thermosphere and overlying ionosphere. Although they are weak precursors to gravity waves in the mesosphere below, acoustic waves may achieve temperature and vertical wind perturbations on the order of approximately tens of Kelvin and m/s throughout the E and F regions. Their perturbations to total electron content are predicted to be detectable by groundbased radar and GPS receivers; they also drive field-aligned currents that may be detectable in situ via magnetometers. Although transient and short lived, ionospheric signatures of acoustic waves may provide new and quantitative insight into …
Dynamics Of Density Cavities Generated By Frictional Heating: Formation, Distortion, And Instability, M. D. Zettergren, J. L. Semeter, H. Dahlgren
Dynamics Of Density Cavities Generated By Frictional Heating: Formation, Distortion, And Instability, M. D. Zettergren, J. L. Semeter, H. Dahlgren
Matthew David Zettergren
A simulation study of the generation and evolution of mesoscale density cavities in the polar ionosphere is conducted using a time-dependent, nonlinear, quasi-electrostatic model. The model demonstrates that density cavities, generated by frictional heating, can form in as little as 90 s due to strong electric fields of ∼120 mV/m, which are sometimes observed near auroral zone and polar cap arcs. Asymmetric density cavity features and strong plasma density gradients perpendicular to the geomagnetic field are naturally generated as a consequence of the strong convection and finite extent of the auroral feature. The walls of the auroral density cavities are …
Nonlinear Ionospheric Responses To Large-Amplitude Infrasonic-Acoustic Waves Generated By Undersea Earthquakes, M. D. Zettergren, J. B. Snively, A. Komjathy, O. P. Verkhoglyadova
Nonlinear Ionospheric Responses To Large-Amplitude Infrasonic-Acoustic Waves Generated By Undersea Earthquakes, M. D. Zettergren, J. B. Snively, A. Komjathy, O. P. Verkhoglyadova
Matthew David Zettergren
Numerical models of ionospheric coupling with the neutral atmosphere are used to investigate perturbations of plasma density, vertically integrated total electron content (TEC), neutral velocity, and neutral temperature associated with large-amplitude acoustic waves generated by the initial ocean surface displacements from strong undersea earthquakes. A simplified source model for the 2011 Tohoku earthquake is constructed from estimates of initial ocean surface responses to approximate the vertical motions over realistic spatial and temporal scales. Resulting TEC perturbations from modeling case studies appear consistent with observational data, reproducing pronounced TEC depletions which are shown to be a consequence of the impacts of …
Measuring The Seeds Of Ion Outflow: Auroral Sounding Rocket Observations Of Low-Altitude Ion Heating And Circulation, P. A. Fernandes, K. A. Lynch, M. Zettergren, D. L. Hampton, T. A. Bekkeng, Et Al.
Measuring The Seeds Of Ion Outflow: Auroral Sounding Rocket Observations Of Low-Altitude Ion Heating And Circulation, P. A. Fernandes, K. A. Lynch, M. Zettergren, D. L. Hampton, T. A. Bekkeng, Et Al.
Matthew David Zettergren
We present an analysis of in situ measurements from the MICA (Magnetosphere-Ionosphere Coupling in the Alfvén Resonator) nightside auroral sounding rocket with comparisons to a multifluid ionospheric model. MICA made observations at altitudes below 325 km of the thermal ion kinetic particle distributions that are the origins of ion outflow. Late flight, in the vicinity of an auroral arc, we observe frictional processes controlling the ion temperature. Upflow of these cold ions is attributed to either the ambipolar field resulting from the heated electrons or possibly to ion-neutral collisions. We measure convection away from the arc (poleward) and downflows of …
Urban Flow And Small Unmanned Aerial System Operations In The Built Environment, Kevin A. Adkins
Urban Flow And Small Unmanned Aerial System Operations In The Built Environment, Kevin A. Adkins
Kevin A. Adkins, PhD
The Federal Aviation Administration (FAA) has put forth a set of regulations (Part 107) that govern small unmanned aerial system (sUAS) operations. These regulations restrict unmanned aircraft (UA) from flying over people and their operation to within visual line of sight (VLOS). However, as new applications for unmanned aerial systems (UAS) are discovered, their capabilities improve, and regulations evolve, there is an increasing desire to undertake urban operations, such as urban air mobility, package delivery, infrastructure inspection, and surveillance. This built environment poses new weather hazards that include enhanced wind shear and turbulence. The smaller physical dimensions, lower mass and …