Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 3/1/2006
Publication Date: 6/9/2006
Citation: French, A.N., Schmugge, T., Ritchie, J.C., Hsu, A.Y., Jacob, F., Ogawa, K. Landcover changes over jornada, new mexico using aster thermal infrared emissivities. Meeting Abstract. p. 19-20. Interpretive Summary:
Technical Abstract: Remote sensing imaging techniques are needed by rangeland managers to help monitor the distribution and densities of vegetation. By providing them with periodic images, these managers could measure the amounts and quality of grazing land vegetation. They could also determine the extent of land degradation, encroachment of undesirable plants such as mesquite and the effectiveness of their restoration strategies. A remote sensing technique that may be very useful for these objectives is based on thermal infrared remote sensing and the estimation of land surface emissivity. The technique is quite different from the widely-known vegetation index approach, which combines visible with near infrared bands to produce indicators such as NDVI. In those instances, resulting images are indicative of green vegetation only and do not provide accurate measures of total vegetation, particularly in arid environments. The alternative emissivity approach provides vegetation density estimates regardless of its chlorophyll content. Land surface emissivity, a property of soils and the geometry of vegetation, is relatively low over bare dry soils—commonly 0.9 or less-- and increases to nearly 1.0 over thickly vegetated terrain regardless of plant color. The research presented shows first results from a three-year study from 2001-3 over the Jornada rangeland in southern New Mexico. Emissivities derived from the satellite sensor ASTER show coherent areas of decreased vegetation. Ground-based surveys at three sites confirm the inferred change. The research results will be important for rangeland management and governmental agencies concerned with mitigating drought in the US Southwest.