Temuulen "Teki" Sankey

Teki_Sankey_x230
Teki Sankey

Assistant Research Professor

 ARD Building, Room 122
1298 S. Knoles Drive
Flagstaff, AZ 86011
Phone: 928-523-7098
E-mail: Temuulen.Sankey@nau.edu

Specialties

  • Remote sensing: multispectral satellite data and 3-dimensional lidar data
  • Geospatial analysis, geoinformatics, geostatistics, GIS
  • Unmanned aerial vehicle (UAV) image analysis and applications
  • Data fusion: spectral data and 3-dimensional point cloud data

Education

  • Ph.D, Land Resources and Environmental Sciences, Montana State University, 2006
  • MS, Land Resources and Environmental Sciences, Montana State University, 2001
  • BA, Foreign Language University, Ulaanbaatar, Mongolia, 1996

Current Vita

Research Interests 

My research focuses on geospatial data analysis and applications in coupled human-environment systems. I use satellite-borne multispectral data and airborne hyperspectral and 3-dimensional point cloud data in geospatial and environmental applications.  The ecosystems I have studied include: grassland-forest ecotones, aspen communities and pinyon-juniper woodlands of the intermountain USA, sagebrush steppe in the northern Great Basin and Columbia Plateau, USA, and grassland steppe and Siberian larch forests of northern Mongolia.

At a global scale, I study cropland distribution and changes over time as they relate to global food security concerns. As a part of the global cropland research, I advise a PhD student and a post-doctorate research scientist at NAU-USGS. You can read more about this project at: http://news.nau.edu/projects-cropland-map-of-the-world-to-be-most-detailed-ever/. In this study, I use continental scale Landsat and MODIS time-series data leveraging NAU’s computing cluster Monsoon.   

At a regional scale, I examine climate change effects on southwestern desert plant communities in collaboration with USGS and National Park Service scientists. This study also uses Landsat time-series data in combination with field-based, long-term vegetation monitoring data.

At a local scale, I currently have a Bureau of Reclamation-funded project to evaluate snow water equivalence and soil moisture response to restoration treatments in ponderosa pine forests in northern Arizona. I advise a PhD student and mentor an undergraduate student in this project. We use a combination of MODIS, Landsat, WorldView-2, and UAV-based high resolution images to examine spatial and temporal variability in snow distribution as impacted by restoration treatments. We expect the high resolution UAV-based data and WorldView-2 images to provide a strong bridge between point-based field measurements and moderate and coarse resolution satellite data. The UAV-based snow-on and snow-off 3-dimensional lidar data can provide high resolution estimates of snow accumulation and spatial patterns as impacted by restoration treatments.  

In many more local-scale studies, my lab group is excited to use our newly-acquired UAV, which was funded by NAU TRIF. The custom-engineered UAV has a unique capability to carry a large payload including a hyperspectral sensor, which images the Earth in over 350 spectral bands at 5 cm resolution, and a lidar scanner, which images the land surface and vegetation in 3-dimensions. The lidar’s cm-resolution, 3-dimensional mapping capability is valuable for a large range of science and engineering applications, spanning from engineering grade mapping of built and natural environments to detailed geologic mapping and inventory of forest biomass and carbon. The hyperspectral imagery is particularly valuable for detailed investigation related to soils, minerals, plants, and water.

Sankey Lab Group

You can read about people in my labhere.

Teaching

EES529: Applied Remote Sensing
GSP529: Applied Remote Sensing

Peer-Reviewed Publications

  • Sankey, T., B. Dickson, S. Sesnie, O. Wang, and L. Zachmann. 2014. WorldView-2 high resolution improves desert invasive plant detection. Photogrammetric Engineering and Remote Sensing (In Print)
  • Sankey, T., R. Shreshtha, J. Sankey, and S. Hardegree. 2013. Lidar-derived carbon estimates in woody encroachment. Journal of Geophysical Research 118: 1144-1155
  • Gould, S., N. Glenn, T. Sankey, and J. McNamara. 2013. Influence of a dense, low-height shrub species on the accuracy of a lidar-derived DEM. Photogrammetric Engineering and Remote Sensing 79: 421-431
  • Sankey, J., M. Germino, A. Hoover, and T. Sankey. 2012. Fire effects on the spatial patterning of soil properties in sagebrush steppe, USA: Meta-analysis. International Journal of Wildland Fires  doi:10.1071/WF11092
  • Turnbull, L., B. Wilcox, J. Belnap, S. Ravi, P. D’Odorico, D. Childers, W. Gwenzi, G. Okin, J. Wainwright, K. Caylor, and T. Sankey. 2012. Understanding the role of ecohydrological feedbacks in ecosystem-state change in drylands. Ecohydrology 5: 174-183
  • Mitchell, J., N. Glenn, T. Sankey, D. Derryberry, and M. Germino. 2012. Remote sensing of sagebrush canopy nitrogen.Remote Sensing of Environment 124: 217-223
  • Mitchell, J., Glenn, N., Sankey, T., Derryberry, D., Anderson, M., and R. Hruska. 2012. Spectroscopic detection of nitrogen concentrations in sagebrush. Remote Sensing Letters 3:285-294
  • Sankey, T.  2011. Decadal-scale aspen change detection using Landsat 5TM and lidar data. Applied Vegetation Science 2012: 84-98
  • Sankey, T. and N. Glenn. 2011. Landsat 5 TM and lidar fusion for sub-pixel juniper tree cover estimates. Photogrammetric Engineering and Remote Sensing 77 (12):1241-1248
  • Glenn, N., Spaete, L., Sankey, T., Derryberry, D., Hardegree, S., and J. Mitchell. 2011. Errors in LiDAR-derived shrub height and crown area on sloped terrain. Journal of Arid Environments 75 (4):377-382
  • Mitchell, J., Glenn, N., Sankey, T., Derryberry, D., Anderson, M., and R. Hruska. 2011. Small-footprint LiDAR estimations of sagebrush canopy characteristics. Photogrammetric Engineering and Remote Sensing 77(5): 521-530
  • Sankey, T.T., and P. Bond.  2011. LiDAR-based classifications of sagebrush communities. Rangeland Ecology and Management 64: 92-98.
  • Sankey, T.T., Glenn, N., Ehinger, S., Boehm, A., and S. Hardegree. 2010. Characterizing western juniper expansion via a fusion of Landsat 5 Thematic Mapper and lidar data. Rangeland Ecology and Management 63: 514-523
  • Spaete, L., Glenn, N., Derryberry, D., Sankey, T., and S. Hardegree. 2010. Vegetation and slope effects on accuracy of a LiDAR-derived DEM in the sagebrush steppe. Remote Sensing Letters 2 (4): 317-326
  • Theau, J., Sankey, T., and K. Weber. 2010. Multi-scale analysis of vegetation indices in a semi-arid environment. GIScience and Remote Sensing 42 (2):1-16
  • Weber, K., Sankey, T., and J. Theau. 2010. Local-scale validation of the surface observation gridding system dataset with in-situ weather observation in a semi-arid environment. International Journal of Remote Sensing 31: 4411-4422
  • Sankey, T., Sankey, J., Weber, K., and C. Montagne. 2009. Geospatial assessment of grazing regime shifts and socio-political changes in a Mongolian rangeland. Rangeland Ecology and Management 62: 522-530
  • Sankey, T.T. 2009. Regional assessment of aspen change and spatial variability at decadal time scales. Remote Sensing 1(4): 896-914
  • Sankey, T., and M. Germino. 2008. Assessment of juniper encroachment with the use of satellite imagery and geospatial data. Rangeland Ecology and Management 61: 412-418
  • Sankey, T. 2008. Learning from spatial variability: Aspen persistence in the Centennial Valley, Montana. Forest Ecology and Management 255: 1219-1225
  • Sankey, T., Moffet, C., and K. Weber. 2008. Post-fire recovery of sagebrush communities: Assessment using SPOT-5 and Very Large-Scale Aerial Imagery. Rangeland Ecology and Management 61: 598-604.
  • Sankey, T. 2008. Spatial patterns of Douglas-fir and aspen forest expansion. New Forests 35:45-55.
  • Sankey, T. 2007. Woody-herbaceous-livestock species interaction. Annals of Arid Zone 46(2):1-28
  • Sankey, T., Graumlich, L., Montagne, C., Lawrence, R., and J. Nielsen. 2006. Twentieth century forest-grassland ecotone shift in Montana under differing livestock grazing pressure. Forest Ecology and Management 234: 282-292
  • Sankey, T., Graumlich, L., Montagne, C., Lawrence, R., and J. Nielsen. 2006. Lower forest-grassland ecotones and 20th century livestock herbivory effects in northern Mongolia. Forest Ecology and Management 233: 36-44

Book Chapters

 Conference Papers, Presentations & Posters

  • Sankey, T. 2014.Predicting snow water equivalence and soil moisture in restored ponderosa pine forests using satellite data. Interstate Stream Commission. Annual Meeting, April 4, Albuquerque, NM.
  • Sankey, T., R. Shrestha, J. Sankey, S. Hardegree, and E. Strand. 2013. Lidar-derived estimate and uncertainty of carbon sink in successional phases of woody encroachment. 12th Biennial Conference of Science and Management on the Colorado Plateau, Sept. 16-19, Northern Arizona University, Flagstaff, AZ.
  • Sankey, T., and S. Hardegree. 2011. Geospatial assessment of decadal scale juniper encroachment into sagebrush steppe. Chapman Conference, Sun Valley, ID
  • Glenn, N., J. Mitchell, L. Spaete, T. Sankey, R. Shrestha, and S. Hardegree. 2011. Modeling semi-arid low-height vegetation with airborne LiDAR. Paper presented at 34th International Symposium on Remote Sensing of Environment. 10-15 April 2011. Sydney, Australia.
  • Mitchell, J., N. Glenn, T. Sankey, M. Anderson, and R. Hruska. 2011. Hyperspectral remote sensing of sagebrush canopy nitrogen. 34th International Symposium on Remote Sensing of Environment. April 2011. Sydney, Australia.
  • Sankey, T., R. Shrestha, J. Sankey, and S. Hardegree. 2011. Lidar-derived carbon estimates in encroaching juniper woodlands. American Geophysical Union. 5-9 December 2011. San Francisco, CA.
  • Spaete, L., J. Mitchell, N. Glenn, R. Shrestha, T. Sankey, J. Murgoitio, S. Gould, T. Leedy, and S. Hardegree. 2011. Vegetation cover and volume estimates in semi-arid rangelands using LiDAR and hyperspectral data. American Geophysical Union. 5-9 December 2011. San Francisco, CA.
  • Glenn, N., J. Mitchell, L. Spaete, T. Sankey, R. Shrestha, and S. Hardegree. 2010. Modeling low-height vegetation with airborne LiDAR. American Geophysical Union. 13-17 December 2010. San Francisco, CA.
  • Sankey, T., N. Glenn, R. Shrestha, and S. Hardegree. 2010. Fine-scale characterization of juniper expansion via lidar data and fusion with Landsat 5 TM. American Geophysical Union. 13-17 December 2010. San Francisco, CA.
  • Mitchell, J., N. Glenn, T. Sankey, D. Derryberry, M. Anderson, and R. Hruska. 2010. Spectroscopic detection of Nitrogen concentrations in sagebrush: Applications in Hyperspectral Remote Sensing. Idaho Section of the Society of Rangeland Management, Winter Meeting. 10-12 November 2012. Idaho Falls, ID.
  • Mitchell, J., N. Glenn, T. Sankey, and D. Derryberry. 2009. LiDAR canopy height measurements in a sagebrush steppe ecosystem. Silvilaser Conference. October, 2010. College Station, Texas.
  • Sankey, T., K. Weber, J. Sankey, and C. Montagne. 2008. Changes in pastoral use and their effects on rangeland productivity. International Conference in Commemoration of the 35th Anniversary of Diplomatic Relations Between Mongolia and Canada - Contemporary Mongolia “Transitions, Development and Social Transformations” November 14-17, Vancouver, B.C., Canada.