Public policy implications of accuracy assessment for fire and deforestation monitoring: Don�t forget the error bars
Irving
Foster
Brown, Woods Hole Research Center and the Federal University of Acre, fbrown@uol.com.br
(Presenting)
Deforestation and fire are two major inter-related driving forces for land cover change in Amazonia. Monitoring their occurrence has been a central focus of the LBA research agenda and of federal and state agencies within Brazil. Data from satellites (Landsat, NOAA-AVHRR, MODIS, GOES) have influenced public policy decisions on the percentage of forest reserves to be maintained on private properties and on the allocation of resources for controlling fires. Like all data, estimates of deforestation and fire events contain inherent uncertainty, which typically manifests itself when estimates are validated in field studies or subject to inter-comparison. The proliferation of accessible imagery, low-cost image processing, and qualified personnel has resulted in differing estimates of deforestation and fire events for the same geographic area. Such differences can lead to confusion among decision makers - be they small farmers or national government representatives - as to what is the �right� value. This confusion is due in part to the tendency of data producers to use excessive numbers of significant figures and to the predisposition of data users to accept estimates as the exact truth, rather than as indicators. The concept of inherent uncertainty has been successfully introduced to the lay public during election campaigns with regards to opinion polls. A similar educational effort could accompany the publication of deforestation and fire estimates, making explicit the uncertainty in these estimates (errors of commission/ omission, classification, and location). The alternative may be a loss of credibility of the remote sensing community when society is faced with multiple, discordant estimates of deforestation and fire events.
Submetido por Irving Foster Brown em 18-MAR-2004
Tema Cient�fico do LBA: LC (Mudan�as dos Usos da Terra e da Vegeta��o)