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Articles 1 - 9 of 9

Full-Text Articles in Physical Sciences and Mathematics

Receiver-Initiated Handshaking Mac Based On Traffic Estimation For Underwater Sensor Networks, Yuan Dong, Lina Pu, Yu Luo, Zheng Peng, Haining Mo, Yun Meng, Yi Zhao, Yuzhi Zhang Nov 2018

Receiver-Initiated Handshaking Mac Based On Traffic Estimation For Underwater Sensor Networks, Yuan Dong, Lina Pu, Yu Luo, Zheng Peng, Haining Mo, Yun Meng, Yi Zhao, Yuzhi Zhang

Publications and Research

In underwater sensor networks (UWSNs), the unique characteristics of acoustic channels have posed great challenges for the design of medium access control (MAC) protocols. The long propagation delay problem has been widely explored in recent literature. However,the long preamble problem with acoustic modems revealed in real experiments brings new challenges to underwater MAC design. The overhead of control messages in handshaking-based protocols becomes significant due to the long preamble in underwater acoustic modems. To address this problem, we advocate the receiver-initiated handshaking method with parallel reservation to improve the handshaking efficiency. Despite some existing works along this direction, the data …


Nasa Maa (Murep Aerospace Academy) Stem Project At York College: Ensuring Future Stem Pipeline, Nazrul I. Khandaker, Shuayb Siddique, Matthew Khargie, Brandon Dhanraj, Zachary A. Sanichar, Mildred M. Selby, Chabenauth Ramnauth, Theresa Deepan, Yougeeta Singh, Krishna Mahabir, Sashi Singh, Omadevi Singh Nov 2018

Nasa Maa (Murep Aerospace Academy) Stem Project At York College: Ensuring Future Stem Pipeline, Nazrul I. Khandaker, Shuayb Siddique, Matthew Khargie, Brandon Dhanraj, Zachary A. Sanichar, Mildred M. Selby, Chabenauth Ramnauth, Theresa Deepan, Yougeeta Singh, Krishna Mahabir, Sashi Singh, Omadevi Singh

Publications and Research

Our ongoing K1-12 NASA-supported STEM activities has served over 5000 children since 2015, largely from groups that are undeserved and underrepresented in the sciences. These STEM activities have been successfully delivered for several years and include earth science, meteorite geology, rocketry, aerodynamics, star gazing, EV3 Mindstorm robotics, basic coding exercises, wind tunnel, 3D-printing, etc., conducted largely through our present MAA (MUREP Aerospace Academy) Project. Corporate funding from the Con Edison and National Grid ensures additional STEM dissemination to the students during the summer operation. Significant positive component of the MAA program is the availability and willingness of the former student …


Observed Differences Between Near-Surface Air And Skin Temperatures Using Satellite And Ground-Based Data, Satya Prakash, Farjana Shati, Hamidreza Norouzi, Reginald Blake Sep 2018

Observed Differences Between Near-Surface Air And Skin Temperatures Using Satellite And Ground-Based Data, Satya Prakash, Farjana Shati, Hamidreza Norouzi, Reginald Blake

Publications and Research

Accurate estimates of long-term land surface temperature (Ts) and near-surface air temperature (Ta) at finer spatio-temporal resolutions are crucial for surface energy budget studies, for environmental applications, for land surface model data assimilation, and for climate change assessment and its associated impacts. The Atmospheric Infrared Sounder (AIRS) and Moderate Resolution Imaging Spectroradiometer (MODIS) sensors onboard the Aqua satellite provide a unique opportunity to estimate both temperatures twice daily at the global scale. In this study, differences between Ta and Ts were assessed locally over regions of North America from 2009 to 2013 …


Impacts Of Climate Extremes On Terrestrial Productivity, Suhua Wei Sep 2018

Impacts Of Climate Extremes On Terrestrial Productivity, Suhua Wei

Dissertations, Theses, and Capstone Projects

Terrestrial biosphere absorbs approximately 28% of anthropogenic CO2 emissions. This terrestrial carbon sink might become saturated in a future climate regime. To explore the issues associated with this topic, an accurate estimate of gross primary production (GPP) of global terrestrial ecosystems is needed. A major uncertainty in modeling global terrestrial GPP is the parameter of light use efficiency (LUE). Most LUE estimates in global models are satellite-based and coarsely measured with emphasis on environmental variables. Others are from eddy covariance towers with much greater spatial and temporal data quality and emphasis on mechanistic processes, but in a limited number …


Quantifying The Effects Of Wind Regimes And Temperature On Surface Melt Over The Antarctic Peninsula (1982–2017) Through Modeling, Remote Sensing And In-Situ Data, Rajashree Datta Sep 2018

Quantifying The Effects Of Wind Regimes And Temperature On Surface Melt Over The Antarctic Peninsula (1982–2017) Through Modeling, Remote Sensing And In-Situ Data, Rajashree Datta

Dissertations, Theses, and Capstone Projects

Surface melting over the Antarctic Peninsula (AP) plays a crucial role for the stability of ice shelves and dynamics of grounded ice, hence modulating the mass balance in a region of the world which is particularly sensitive to increasing surface temperatures. Understanding the processes that drive melting using surface energy and mass balance models is fundamental to improving estimates of current and future surface melting and associated sea level rise through ice-shelf collapse. This is even more important in view of the specific challenges presented by how circulation patterns over the topographically-complex Antarctic Peninsula, especially foehn winds, impact surface melt. …


Climate-Informed Environmental Inflows To Revive A Drying Lake Facing Meteorological And Anthropogenic Droughts, Aneseh Alborzi, Ali Mirchi, Hamed Moftakhari, Iman Mallakpour, Sara Alian, Ali Nazemi, Elmira Hassanzadeh, Omid Mazdiyasni, Samaneh Ashraf, Kaveh Madani, Hamid Norouzi, Marzi Azarderakhsh, Ali Mehran, Mojtaba Sadegh, Andrea Castelletti, Amir Aghakouchak Jul 2018

Climate-Informed Environmental Inflows To Revive A Drying Lake Facing Meteorological And Anthropogenic Droughts, Aneseh Alborzi, Ali Mirchi, Hamed Moftakhari, Iman Mallakpour, Sara Alian, Ali Nazemi, Elmira Hassanzadeh, Omid Mazdiyasni, Samaneh Ashraf, Kaveh Madani, Hamid Norouzi, Marzi Azarderakhsh, Ali Mehran, Mojtaba Sadegh, Andrea Castelletti, Amir Aghakouchak

Publications and Research

The rapid shrinkage of Lake Urmia, one of the world's largest saline lakes located in northwestern Iran, is a tragic wake-up call to revisit the principles of water resources management based on the socio-economic and environmental dimensions of sustainable development. The overarching goal of this paper is to set a framework for deriving dynamic, climate-informed environmental inflows for drying lakes considering both meteorological/climatic and anthropogenic conditions. We report on the compounding effects of meteorological drought and unsustainable water resource management that contributed to Lake Urmia's contemporary environmental catastrophe. Using rich datasets of hydrologic attributes, water demands and withdrawals, as well …


Numerical Study Of The Interplay Between Thermo-Topographic Slope Flow And Synoptic Flow On Canopy Transport Processes, Xiyan Xu, Chuixiang Yi, Leonardo Montagnani, Eric Kutter May 2018

Numerical Study Of The Interplay Between Thermo-Topographic Slope Flow And Synoptic Flow On Canopy Transport Processes, Xiyan Xu, Chuixiang Yi, Leonardo Montagnani, Eric Kutter

Publications and Research

Canopy flow resulting from interaction between thermo-topographic slope flow and large-scale synoptic flow is very complicated and has been poorly understood. We apply a Reynolds-averaged Navier-Stokes (RANS) turbulence model to investigate how the interactions between local flow and synoptic winds affect CO2 movement in the canopy layer at the Renon site in the Italian Alps. Since the RANS simulations are compared to the data measured by multiple-tower experiments conducted during CarboEurope-IP advection campaigns (ADVEX) at Renon, our study can be viewed as a case study of a relatively common wooded slope. The thermal condition in the canopy is directly …


Estimation Of Consistent Global Microwave Land Surface Emissivity From Amsr-E And Amsr2 Observations, Satya Prakash, Hamidreza Norouzi, Marzi Azarderakhsh, Reginald Blake, Catherine Prigent, Reza Khanbilvardi Apr 2018

Estimation Of Consistent Global Microwave Land Surface Emissivity From Amsr-E And Amsr2 Observations, Satya Prakash, Hamidreza Norouzi, Marzi Azarderakhsh, Reginald Blake, Catherine Prigent, Reza Khanbilvardi

Publications and Research

Accurate estimation of passive microwave land surface emissivity (LSE) is crucial for numerical weather prediction model data assimilation, for microwave retrievals of land precipitation and atmospheric profiles, and for better understanding of land surface and sub-surface characteristics. In this study, global instantaneous LSE is estimated for the 9-year period from the Advanced Microwave Scanning Radiometer - Earth Observing System (AMSR-E) and for the 5-year period from the Advanced Microwave Scanning Radiometer - 2 (AMSR2) sensors. Estimates of LSE from both sensors were obtained by using an updated algorithm that minimizes the discrepancy between the differences in penetration depths from microwave …


Convective Transport Of Tropical Marine Boundary Layer Species Into The Upper Troposphere And Relation To Species Lifetime: In Situ Measurements And Global Model Simulation, Sofia M. Chelpon Jan 2018

Convective Transport Of Tropical Marine Boundary Layer Species Into The Upper Troposphere And Relation To Species Lifetime: In Situ Measurements And Global Model Simulation, Sofia M. Chelpon

Dissertations and Theses

This study investigates the influence of tropical deep convection on distribution of trace gasses in the tropical upper troposphere (UT) using data from the Convective Transport of Active Species in the Tropics (CONTRAST) Experiment conducted over the tropical western Pacific during January and February of 2014. Fifty-five chemical species measured during the CONTRAST campaign are analyzed with lifetimes ranging from less than a day to several years. The vertical profiles of these species suggest that they fall into three main groups delineated by their lifetime: 1) very long-lived trace gases demonstrating a nearly constant vertical structure, 2) intermediate lifetime species …