Earth Observing System (EOS) Aura Science Data Validation Plan

Executive Summary I. The Aura Mission The Aura satellite is scheduled to be launched in 2003 in a sun-synchronous polar orbit for a nominal mission of five years. The four Aura instruments are: the High Resolution Dynamics Limb Sounder (HIRDLS), measuring infrared emission profiles from high resolution atmospheric limb scans behind Aura; the Microwave Limb Sounder (MLS), obtaining limb emission profiles ahead of the satellite; the Ozone Monitoring Instrument (OMI), a nadir-viewing UV/VIS imaging spectrometer with high spatial resolution; the Tropospheric Emission Spectrometer (TES), a Fourier Transform infrared spectrometer measuring in both the nadir and the limb mode behind Aura. Section 2 of this document gives the Aura science goals, a description of the instruments and measurement characteristics. The top-level objectives are to resolve the following science questions: • Is the ozone layer changing as expected? • Do we understand the transport of gases within the stratosphere and between the stratosphere and troposphere? • What are the sources and distributions of tropospheric pollutants? • What are the roles of upper tropospheric water vapor, aerosols, and ozone in climate change? The main products from Aura will be: (4) aerosol optical thickness. (5) cloud information. (6) volcanic SO 2. Section 3 provides more details about these products and their expected uncertainties. II. Summary of Aura Plans for Pre-launch Activities Three major pre-launch activities that are necessary for successful (post-launch) validation of Aura products are: (1) Instrument calibration, (2) Algorithm testing, and (3) Compilation of spectroscopic data and other databases. These are discussed in section 4. II.1 Instrument Calibration Instrument calibration is closely tied to the continuing hardware development and testing of the Aura instruments. Each instrument will have detailed specific issues and schedules to follow. Pre-launch instrument and Project reviews and reports provide the means to assess the progress of the calibration plans that are briefly discussed (section 4.1). ii II.2 Algorithm Testing Pre-launch algorithm testing is discussed in section 4.2. The success of this testing directly impacts the quality of processed data after launch. Current test plans are summarized for each instrument team's algorithm. Where feasible, algorithms will be tested on data obtained by earlier satellite instruments. Algorithm mathematical approaches and some accuracy estimates are given in the Algorithm Theoretical Basis Documents. The Algorithm Working Group will guide some of the common activities (e.g., the use of a common model atmosphere for simulations and end-to-end testing), but much of the detailed …