Algorithm Development for Vegetation Change Detection and Environmental Monitoring

Louis A. Scuderi1, Amy Ellwein2, Enrique Montano3 and Richard P. Watson4, Center for Rapid Environmental Assessment and Terrain Evaluation (CREATE)

University of New Mexico, Albuquerque, NM, 87131, USA(1tree@unm.edu, 2ellwein@unm.edu, 3tresmont@unm.edu, 4rwatson@unm.edu)

CREATE has been involved in monitoring efforts that focus on the assessment of environmental conditions that lead to vegetation change in arid and semi-arid ecosystems. In this work we have developed approaches that augment existing MODIS algorithms, imagery, and analysis products such that they can be used in combination with ancillary data and models from other sources. These activities are crosscutting with a goal of integration of NASA Earth science products into decision tools for resource management.

In arid and semi-arid regions, such as the American Southwest, vegetation is susceptible to periodic droughts that may last many years. Even in good years precipitation in these environments is characterized by high spatial variability. CREATE is participating in efforts to quantify the variability of precipitation and vegetative response over timescales ranging from days to decades and over spatial scales ranging from an individual MODIS resolution cell to entire drainage basins. This information is used to provide assessments of the impact of meteorological variability on arid and semi-arid ecosystems. As a baseline for all of our studies, CREATE is participating in an effort that focuses on estimation of the daily evapotranspirative flux (ET) across the state of New Mexico (illustrated to right). The goal of the work is to produce daily ET maps for input into the New Mexico Decision Support System for Hydrologic Modeling And Prediction (HMAP) and for assessment of vegetation response to meteorological variability.

CREATE is working with the US Bureau of Land Management (BLM) to augment their Vegetative Monitoring & Analysis Program (VMAP) which is used to monitor rangeland health and to assess and evaluate forage yields, vegetative production, ground cover, plant frequency density and disturbance. A limitation of VMAP is that its large set of ground-based observations is infrequently updated and hence VMAP is not responsive to change on short time scales. By providing information on short-term local vegetation response as derived from MODIS imagery and by scaling this data to VMAP resolution, ecosystem change can be examined at a finer temporal scale than has previously been possible and the limiting factors of precipitation and moisture availability more fully understood. Derivative products from this work provide valuable information to ranchers and farmers who are reliant on weather, rainfall, and vegetation information to make critical economic decisions.

Research on the response of vegetation to short and long-term weather variability offers insight into environmental processes that are not apparent in larger global scale analyses, and provides information valuable to the application of EOS data to issues of national importance. The southwest United States has experienced significant and extensive drought since the mid-1990. In response, many areas have experienced vegetation die off and/or invasion by non-native species. CREATE is using MODIS data and modified algorithms to document the effects of meteorological variability and long-term climate change and to assess the implications of this change on local, regional and continental-scale ecological, economic and social systems (illustrated to left).

MODIS May 31, 2002 (Terra)

Band 1 Band 2 Band 3

Band 4 Band 5 Band 6

Brassica tournefortiiSahara mustardMojave Desert, California and

Arizona, USA. Parker Dune study area outlined in red.

Rapid Invasion of the Parker Dunes by Brassica tournefortii since 2000

Native Species Early-stage

Full CoverMid-stage

Sahara mustard is native to semi-arid and arid deserts of North Africa and the Middle East, as well as Mediterranean lands of southern Europe in habitats similar to those it now occupies in North America. The plant apparently was first collected in North America in 1927. Sahara mustard probably was introduced with date palms brought from the Middle East in the early 1900’s with the development of the date industry in the Coachella Valley. During rains, a sticky gel forms over the seed case that permits seeds to disperse long distances by adhering to animals. The rapid spread of Brassica tournefortii through the Sonoran Desert, with first occurrences along roadsides, may be related to its ability to adhere to automobiles during rare periods of wet weather. In the Parker Dunes area Brassica appeared in 2000. We are mapping the advance of this invasive species with MODIS.