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Remote Sensing of Land Surfaces

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3D Global Vegetation legend

      Download the full resolution (1km) map here (TIF, 67MB) and map legend here. An error map can be downloaded here (TIF, 43KB).

Project Description

This website presents the research projects of Dr. Marc Simard, Senior Scientist at the Jet Propulsion Laboratory. The overall objective is to combine radar and lidar remote sensing to characterize the forested landscapes in 3D. The science products generated by Simard and collaborators have four main components:

  1. Global scale mapping of canopy height and biomass at 1km spatial resolution.
  2. Improving Shuttle Radar Topography Mission (SRTM) elevation dataset using ICESat's Geoscience Laser Altimeter System (GLAS).
  3. High spatial resolution mapping of canopy height and biomass using polarimeteric synthetic aperture radar interferometry (polinSAR) and LiDAR.
  4. Mapping of mangrove forests canopy height, biomass, productivity and assessment of vulnerability to anthropogenic activity and sea level change.

These projects are funded through the NASA MEaSUREs (1,2), Terrestrial Ecology (3) and Land Cover Land Use Change (LCLUC) (4) programs.

The recent availability of global scale datasets such as SRTM, MODIS, Landsat, and ICESat/GLAS enable scientists to map the entire Earth's land surface with unprecedented details.

ICESat/GLAS measurements are spatially sparse measurements that provide, nonetheless, valuable information about ground elevation as well as canopy structure. Thus GLAS can be used to complete datasets, to produce global maps of canopy height. The combination of ICESat/GLAS and SRTM has been fruitful. Since mangrove forests grow around sea level, SRTM provide a first estimate of forest height (interferometric phase center) which can be calibrated with field and GLAS data. We produced maps of mangrove canopy height and biomass in several regions of the World. More details here.

To obtain high spatial resolution 3D maps, we use airborne radar and lidar sensors, in particular, UAVSAR and LVIS. In this case, our research aims at developing polarimetric synthetic aperture radar interferometry (polinSAR) for repeat-pass systems. That is, using a single radar antenna flown at least twice over a same site. This configuration is poised by the so-called temporal decorrelation that can significantly reduce interferometric coherence. Temporal decorrelation is due to short and long term changes in the target properties resulting from wind, precipitation, vegetation growth, etc. Simard, Hensley and Dubayah designed a UAVSAR flight campaign to measure the impact of temporal decorrelation on the repeat-pass interferometric signal. UAVSAR flew several sites with a variety of vegetation types:

  1. The Laurentides Wildlife Reserve, Québec, Canada (Boreal)
  2. The Hubbard Brook/Bartett forests, New Hampshire (Temperate)
  3. The Howland experimental forest, Maine (Temperate)
  4. The King's Canyon National Park, California (Temperate)
  5. La Selva experimental forest, Costa Rica (Tropical)
  6. Osa Peninsula, Costa Rica (Tropical)

Active Remote Sensing Super Sites

The goal of these Super Sites is to provide researchers with sufficient remote sensing and field datasets to develop algorithms, calibrate and validate their results, and compare results with other researchers. In the frameworks of 3D land mapping, the Super Sites will be specialized in radar and lidar (i.e. active) remote sensing. Lets start with one Super Site, the Laurentides Wildlife Reserve (Réserve Faunique des Laurentides), Québec, Canada. The Reserve offers a range of characteristics such as an elevational gradient with forests ranging from temperate to boreal forest, a large range of elevations (~1000m) and slopes, 2 National Parks, one experimental forest (Forêt Montmorency, U. Laval) and large areas of lumber and fire activity, ideal for change mapping. Since 2009, several airborne sensor flew over the Reserve: UAVSAR (2009), LVIS (2009), DBSAR (2010), SIMPL (2010) and spaceborne data was acquired with ALOS/PALSAR and TanDEM-X. This website will be updated with more Super Sites later.

Funding for Simard's projects provided by NASA's Terrestrial Ecology, MEaSUREs and Land Cover Land Use Change (LCLUC) programs.

Using this website

The first page shows a Google Map overlay of a 10km spatial resolution version of the Global Map of Canopy Height and the error estimated from ICESat/GLAS individual shots. You can access the original datasets (1km resolution) by clicking below the Google Map interface. These products are described in Simard et al., 2011.

The markers indicate the super sites (one for now). You can access the Super Sites webpage by clicking the marker. On the Super Site page, you can choose to show several datasets. The information related to these appears at the bottom. In the case of LVIS and UAVSAR data, please click on the swath to see the information related to that swath. Within the bottom frame, you can also download your favorite dataset. ICESAT/GLAS shots are clustered at coarse scale. Zooming allow you to see individual shots. At fine scale, the transparent circle at the location of the ICESAT/GLAS shot represents the scale of a 70m footprint. Several datasets are also accessible in KML or ASCII format beside their respective buttons.

Let us know

In order to obtain updates about new datasets and products over the Super Sites, please send an email to the Principal Investigator Dr. Marc Simard.

Selected Publications

Simard, M., Pinto, N., Fisher, J., Baccini, A., (2011), "Mapping forest canopy height globally with spaceborne lidar", Journal of Geophysical Research, VOL. 116, G04021, 12 PP., 2011, doi:10.1029/2011JG001708

Fatoyinbo, T.E. and Simard, M. (2011), "Mapping of Africa's mangrove forest extent, height and biomass with ICEsat/GLAS and SRTM data fusion", International Journal of Remote Sensing, in print

Swatantran, A., Dubayah, R., Goetz, S., Hofton, M., Betts, M., Sun, M., Doran,P., Simard, M., Holmes,R. (2011), "Mapping Migratory Bird Habitat Quality using Remote Sensing Data Fusion". Public Library of Science, eISSN-1932-6203.

Victor H. Rivera-Monroy, Robert R. Twilley, Stephen E. Davis, III, Daniel L. Childers, Marc Simard, Randolph Chambers, Rudolf Jaffe, Joseph N. Boyer, David T. Rudnick, Keqi Zhang, Edward Castaneda-Moya, Sharon Ewe, Rene M. Price, Carlos Coronado-Molina, Michael Ross, Thomas J. Smith, III, Beatrice Michot, Ehab Meselhe, William Nuttle, Tiffany Troxler, and Gregory, (2010), "The Role of the Everglades Mangrove Ecotone Region (EMER) in Regulating Nutrient Cycling and Wetland Productivity in South Florida" , Special issue of Critical Reviews in Environmental Science and Technology, 41(S1):1-37

Lavalle, M. and Simard, M. (2010), "Time-varying volume coherence in polarimetric SAR interferometry", IEEE Transactions on Geoscience and Remote Sensing, In print.

Simard M, Fatoyinbo T.E., Pinto N (2009), "Mangrove Canopy 3D Structure and Ecosystem Productivity Using Active Remote Sensing", book chapter In Remote Sensing of Coastal environments, Taylor and Francis Group LLC, Yeqiao Wang ed.

Fatoyinbo, T. E., M. Simard, R. A. Washington-Allen, and H. H. Shugart, "Landscape-scale extent, height, biomass, and carbon estimation of Mozambique's mangrove forests with Landsat ETM+ and Shuttle Radar Topography Mission elevation data", J. Geophys. Res., 113, G02S06, 2008, doi:10.1029/2007JG000551

Zhang K., Simard M., Ross M., Rivera-Monroy V. H., Houle P., Ruiz P., Twilley R. R., Whelan K., "Airborne Laser Scanning Quantification of Disturbances from Hurricanes and Lightning Strikes to Mangrove Forests in Everglades National Park, USA." Sensors. 2008; 8(4):2262-2292.

Simard, M., Rivera-Monroy, V.H., José Ernesto Mancera-Pineda, Castaneda-Moya, E.,Twilley, R., "A Systematic Method for 3D Mapping of Mangrove Forests Based on Shuttle Radar Topography Mission Elevation Data, ICESat/GLAS Waveforms and Field Data: Application to CiĆ©naga Grande de Santa Marta, Colombia," Remote Sensing of the Environment, Vol. 112/5, pp. 2131-2144, doi:10.1016/j.rse.2007.10.012. 2008.

M. Simard, K. Zhang, V. H. Rivera-Monroy, M. Ross, P. Ruiz, E. Castañeda-Moya, E. Twilley, E. Rodriguez., "Mapping Height and Biomass of Mangrove Forests in the Everglades National Park with SRTM Elevation Data", Photogrammetric Engineering & Remote Sensing, Vol. 72, No. 3, March 2006, pp. 299-311.