HR: 1330h
AN: H23B-05    [Abstracts]
TI: EFFECT OF SCALING TRANSFER BETWEEN EVAPOTRANPIRATION MAPS DERIVED FROM LANDSAT7 AND MODIS IMAGES
AU: * Hong, S
EM: hong@nmt.edu
AF: New Mexico Tech, P.O.BOX 3097, SOCORRO, NM 87801 United States
AU: Hendrickx, J M
EM: hendrick@nmt.edu
AF: New Mexico Tech, P.O.BOX 3097, SOCORRO, NM 87801 United States
AU: Borchers, B
EM: borchers@nmt.edu
AF: New Mexico Tech, P.O.BOX 3097, SOCORRO, NM 87801 United States
AB: Remotely sensed images of the Earth's surface provide information about the spatial distribution of evapotranspiration. Since, the spatial resolution of evapotranspiration predictions depends on the sensor type; scaling transfer between images of different scales needs to be investigated. The objective of this study is to investigate the effect of the scaling transfer between evapotranspiration maps derived from Landsat7 and MODIS images. In this study, the Surface Energy Balance Algorithm for Land (SEBAL) was used to derive evapotranspiration maps from Landsat7 Thematic Mapper (TM) and Moderate Resolution Imaging Spectroradiometer (MODIS) images. LandSat7 has a spatial resolution of 60 m, MODIS of 1000 m. Two up-scaling procedures are evaluated. The first consists of averaging 60 by 60 m LandSat pixels of radiances to obtain 1000 by 1000 m pixels at the MODIS scale before SEBAL is applied. The second consists of first applying SEBAL and then to average evapotranspiration rates from 60 m to 1000 m spatial resolution. The averaging process (aggregation) will include calculating arithmetic and geometric means. In the down-scaling process (MODIS scale to LandSat scale), a 16 days earlier or later LandSat image will be used to characterize the fine scale variability within the large MODIS pixels. Two down-scaling procedures are evaluated. The first consists of down-scaling the original MODIS radiance data; the second of down-scaling the evapotranspiration maps at MODIS scale. The results of this study show that up- and down-scaled ET maps over the Middle Rio Grande Basin show a relatively good agreement with evapotranspiration maps directly derived from LandSat and MODIS images.
DE: 1800 HYDROLOGY
DE: 1818 Evapotranspiration
SC: Hydrology [H]
MN: 2005 Joint Assembly