Cooperative Institute for Research in Environmental Sciences

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Special Seminar: My career in land remote sensing: from little to big analysis of satellite terrestrial information

Special Seminar: My career in land remote sensing: from little to big analysis of satellite terrestrial information

Dr. David Roy's research interests include the development of remote sensing and advanced computing methods to map and characterize terrestrial change, global Petabyte volume satellite data processing and visualization, and the causes and consequences of land cover and land use change.

He is co-chair of the USGS NASA Landsat Science Team, and a member of the NASA MODIS land, NASA Land-Cover/Land-Use Change, and the GOFC-GOLD Fire Implementation science teams. He is chair of the US Land Processes (LP) Distributed Active Archive Center (DAAC) User Working Group (UWG) and a member of the NASA Earth Exchange (NEX) UWG. He has led research grants that total more than $12 million as principal investigator and more than $11 million as a co-investigator. He has an h-index >30 and his research has been cited >7000 times.

David has a Ph.D. from the Department of Geography, Cambridge University U.K. (1994), an M.Sc. in Remote Sensing and Image Processing from the Department of Meteorology, University of Edinburgh (1988), and a B.Sc. in Geophysics from the Department of Environmental Science, University of Lancaster (1987). He held post-doctoral research fellowships at the U.K. Natural Environment Research Council Unit for Thematic Information Systems, University of Reading, and at the Space Applications Institute, Joint Research Centre of the European Commission, Italy. Before moving to South Dakota State University, where he is a professor in the Geographic Information Science Center of Excellence, he was an associate research scientist in the Department of Geographical Sciences at the University of Maryland and led the MODIS Land Data Operational Product Evaluation group at NASA's Goddard Space Flight Center for eight years.

Abstract: Dr. Roy will talk about his research, where it has come from, and where it is going with an emphasis on the generation of consistent global long-term satellite data records and prospects for near real-time land surface monitoring, the emerging relevance of the commercial sector, and the need for advocacy for space agency continuity of satellite environmental remote sensing systems.

Cryospheric and Polar Processes Seminar: Dr. Albert Chen

Cryospheric and Polar Processes Seminar: Dr. Albert Chen

InSAR Remote Sensing: Principles and Applications to Greenland and Alaska

Dr. Albert Chen, Department of Gephysics, Standford University


Interferometric synthetic aperture radar (InSAR) is a technique for forming images of the Earth using data acquired by a spaceborne or airborne radar instrument. The complex phase of InSAR images can be used to measure Earth surface topography and deformation, while the secondorder phase statistics (coherence) can be related to temporal surface change and subsurface structure. After a brief overview of InSAR principles, error sources, and uncertainties, we present two applications of InSAR to cryosphere geophysics. First, we examine the use of InSAR coherence for studying snow accumulation rate in the dry-snow zone of the Greenland Ice Sheet.

We show a method for correcting decorrelation effects due to ionospheric inhomogeneity. We pose the estimation of accumulation rate from InSAR data as a nonlinear inverse problem, and compare our results with in-situ observations. Second, we use InSAR phase to study active layer thickness in regions of permafrost in Northern Alaska. We relate seasonal thaw subsidence measured by InSAR to active layer thickness, and use InSAR time series analysis to mitigate the effects of atmospheric noise.


Albert C. Chen was born in Columbus, Ohio and grew up in New York and Michigan. He received the B.S.E. degree from the University of Michigan, Ann Arbor, in 2006. He also received the M.S. and Ph.D. degrees in electrical engineering from Stanford University in 2008 and 2014, respectively. Currently, he is a postdoctoral scholar in the Department of Geophysics at Stanford University. Albert has also been an engineering intern with The Boeing Company and Visteon Corporation. His research interests range from interferometric synthetic aperture radar (InSAR), remote sensing, radar instrument design, and signal processing to cryosphere and near-surface geophysics. He is a member of AGU and IEEE, and has also served as teaching assistant for undergraduate and graduate courses in signal and image processing.

Analytical Chemistry Seminar: Ryan Davis

Analytical Chemistry Seminar: Ryan Davis

Jointly sponsored by the Department of Chemistry and Biochemistry, CIRES, and the Environmental Program

Novel Phase Transitions of Optically Levitated Microdroplets: Contacts and Glasses Relevant to the Atmosphere

Ryan Davis, University of Colorado

The phase state and water content of atmospheric particles influence the particle's size, optical properties and chemical reactivity with important but poorly constrained effects on air quality and climate.  One challenging problem is predicting the ambient conditions required to initiate a phase transformation of a particle from liquid to solid, particularly when consideration is given to multi-particle interactions as well as chemical composition of the liquid droplet.  One such example is the phenomenon of contact nucleation.  Presented here are the first direct observations of contact nucleation of crystalline ammonium sulfate using a recently developed long-working distance optical trap.  Insight is given to the mechanism behind contact nucleation.  The effect of amorphous or glassy phase states will also be discussed.


CIRES Fellows Room, Ekeley S274 1665 Central Campus Mall - 1665 Central Campus Mall, CIRES - University of Colorado