On-orbit performance of the Earth Observing System Moderate Resolution Imaging Spectroradiometer; first year of data

The Moderate Resolution Imaging Spectroradiometer (MODIS) completed the first year of science data acquisition on February 24, 2000. The overall performance of the sensor and the on-board calibration systems for this first year have been very good. Several features of the performance lead to characteristics in the data set that merit special attention. These items are sometimes called data product caveats, and are described here. Uncertainty budgets for the 0.555-μm band, the 1.240-μm band and the 12.000-μm band are presented at several days throughout this first year. The uncertainty is estimated to be decreasing with time during this period, and to be near 1.8% in reflectance factor for 0.555 μm, 1.9% for the reflectance factor product for the 1.240 μm band, and 0.7% for the 12.000-μm band at nadir at the end of the first year. Degradation of the solar diffuser is 2.3% at 0.412 μm, known to an uncertainty of ±0.5%. Solar diffuser degradation for wavelengths longer that 0.5 μm is indistinguishable from the uncertainty in trend determination for the first year. Mirror side degradation at 0.412 μm is 6±0.5%, with a mirror side difference of an additional 3%. The performance present in the data at the end of year 1 provides significant encouragement that many improvements in our understanding of the Earth system performance can and will be based on MODIS data during the coming years.