TRACKING THE PROGRESS OF A COASTAL SALTMARSH MITIGATION PROJECT USING A 10-YEAR DATASETOF HIGH RESOLUTION DIGITAL MULTI-SPECTRAL IMAGERY

摘要

Near-anniversary-date ADAR (Airborne Data Acquistion and Registration)rnmultispectral image data were acquired over Sweetwater Marsh in San Diego, CArnbetween 1991-2000.rnImage frames from each flight date were registered to a network adjusted referencernimage and mosaicked with lm pixel resolution. Regression models were developedrnfrom pseudo-invariant features common to all flight dates and the mosaics werernradiometrically normalized with the reference image. NDVI and spatial variance ofrnNDVI values were derived from the normalized NIR and red bands and used asrnsimple metrics to determine whether the trajectory of the constructed marsh wasrnapproaching the target state of the surrounding natural marshes.rnThe results indicate that NDVI for the restoration marsh sites was higher thanrnadjacent urban areas for all dates but consistently lower than the target naturalrnmarshes. The mitigation marsh also had higher spatial variability of NDVI valuesrnthan the natural marsh indicating a higher degree of patchiness.rnA real-time kinematic GPS survey was used to locate a random selection of points inrnthe natural and restored marsh areas to determine the qualitative differences. Thernconstructed marsh was characterized by 50-90% bare soil and low plant speciesrndiversity. The natural marsh exceeded 90% vegetative cover and had higher plantrnspecies diversity.