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The Mission Performance Working Group is a body composed of experts from EUMETSAT, NASA, ESA, NOAA and CNES. The group meets on a regular basis, and it is aiming at monitoring the Sentinel-6MF overall altimetry mission performance. The group assesses on mission and payload performance budgets, data products quality, algorithm development, new processor verification and validation performance, calibration and validation planning, as well as provides scientific support to the reprocessing calibration and validation, key mission instrument meetings and mission performance meetings. The MPWG activities are similar to those done by the MSEs as per previous Jason mission. In this presentation, the MPWG will share with the OSTST the latest calibration and validation findings including any mission scientific challenges. Moreover, we will present the scientific plans for Sentinel-6MF evolutions, and provide an estimated timeline for these evolutions to be available to the Sentinel-6MF user community.

A microwave range transponder has been operating at the CDN1 Cal/Val site on the mountains of Crete for about 6 years to calibrate international satellite radar altimeters at the Ku-band. This CDN1 transponder is part of the European Space Agency Permanent Facility for Altimetry Calibration (PFAC), and has been producing continuously as of 2015 a time series of range biases for Sentinel-3A, Sentinel-3B, Sentinel-6A, Jason-2, Jason-3 and CryoSat-2. A second range and sigma-0 transponder at a crossover location of Sentinel-6 “Michael Freilich” on the island of Gavdos is also operational as of 11-Oct-2021. This work presents a thorough examination of the transponder Cal/Val responses in an effort to understand and determine which factors are responsible for the observed changes in the Cal/Val results. Fourteen uncontrolled and three controlled sources of variations have been investigated. The latest calibration results for the Jason-3, the Copernicus Sentinel-3A and -3B, Sentinel-6A and the HY-2B radar altimeters will be described based on four sea-surface and two transponder Cal/Val sites of the PFAC in west Crete, Greece. Absolute biases for Jason-3, Sentinel-6A, Sentinel-3A, Sentinel-3B and HY-2B will be given using various techniques, infrastructure and settings.

The altimetry data record (1993-2022) has enabled the global mean sea level (GMSL) rise to be quantified. Not only is the sea level rising, but it is accelerating (Dieng et al., 2017; Nerem et al., 2018; Ablain et al. 2019) and understanding this acceleration is necessary both to support society’s response to climate change and to inform climate research on the sea level budget, greenhouse gas forcing and the Earth energy imbalance. Here we describe work on quantifying the uncertainty on the sea level climate data record, and identifying the uncertainty needed to provide new answers to the climate research questions. Work by Ablain et al. (2019) and updated in Guérou et al. (2022) at a global scale, has quantified GMSL rise as +3.3 mm/yr (90% confidence uncertainties 0.3 mm/yr) over 1993-2021. Its acceleration has been quantified at 0.12 ± 0.05 mm/yr². At local scales, (Prandi et al. 2021), the sea level is rising almost everywhere over the globe, at rates ranging between 0 and 6 mm/yr, with uncertainties ranging from 0.8 to 1.2 mm/yr depending on the location. The local sea level accelerations are ranging between -1 mm/yr² and +1 mm/yr² with uncertainties between 0.057 and 0.12 mm/yr² (Prandi et al., 2021). Here we present more recent work refining these uncertainty estimates through a metrological approach that propagates uncertainties, and error covariance structures, through the full processing chain of the altimeter measurement from the raw waveform to GMSL, using methods described in Mittaz et al. (2019). We review the assumptions in the derivation of the retracking model from the radar equation, consider error correlation structures in the corrections, and provide fresh consideration of the error covariance matrix, building on the earlier research. The work was developed in the ASELSU project funded by ESA. The project has also reviewed the climate science research questions to understand the need for improved altimeter observations. There are three major science questions that require accuracies greater than those currently achieved. These questions are the closure of the sea level budget, the detection and attribution of the signal in sea level that is forced by greenhouse gas emissions (GHG) and the estimate of the Earth energy imbalance (EEI). Dieng et al. 2017: https://doi.org/10.1002/joc.4996. Nerem et al. 2018: https://doi.org/10.1073/pnas.1717312115 Ablain et al 2019: https://doi.org/10.5194/essd-2019-10 Guérou et al. 2022: https://doi.org/10.5194/egusphere-2022-330 Prandi et al. 2021: https://doi.org/10.1038/s41597-020-00786-7 Mittaz et al. 2019: https://doi.org/10.1088/1681-7575/ab1705

The main payload of Sentinel-6 Michael Freilich is a dual-band (Ku and C) pulse-width limited radar altimeter, called Poseidon-4, that transmits pulses at a high pulse repetition frequency thus making the received echoes phase coherent and suitable for azimuth processing. Among the different unique characteristic of Poseidon-4, it is worth recalling that digital pulse range compression is performed on-board to transform the received chirp using a matched filter. Thus, a proper calibration approach has been developed, including both an internal and external calibration. In particular, this abstract presents the long-term monitoring of the internal calibration data for chirp replica and for attenuator that are processed on ground by ad-hoc tools provisioned by Aresys to ESA: • CAL1 INSTR: This mode measures the internal instrument transfer function in Ku band and in C band. The results of these measures can be taken into account at Digital compression level in the chirp replica(f) to optimize the impulse response of the instrument. • CAL ATT: Since amplification gain control knowledge directly impacts the σ0 measurements, an attenuation calibration is included in the design. This measures the top of the range impulse response within the full attenuation dynamic range that is then matched to a corresponding value on ground. The performance of Poseidon-4 altimeter is here presented by analysis of the long-term monitoring of the on-ground processed data from CAL1 INSTR and CAL ATT calibration sequences commanded on board. The analysis of such calibration data allows to verify that the instrument has reached the requirements and that it is maintaining the key performance over its life. Moreover, in-depth analysis of the calibration data revealed how the instrument depends on its temperature and on the orbit of the satellite.

The Sentinel. 6 satellite has a new platform, with a very different geometry from the preceding missions like Jason 1,2,3. The main difference is that the solar array panel is now fixed on the satellite body, and the satellite has a fixed attitude in the local orbital frame (with small rotations for geodetical pointing and ground velocity alignment). As a consequence the sun direction relative to the panels has important variations along one orbit. On Jason 3 the illumination of the solar array panels is always close to the normal direction : as a consequence the solar radiation pressure force produced by the panels has a well defined direction independent of the material coefficients. Also, the amplitude does not depend on the balance between the electrical energy production of the array and the material thermally absorbed part. This thermally absorbed part has no impact on the global force, due to a similar re-radiation on both surfaces of the panels. On Sentinel 6, this property does not hold anymore, and the standard modeling of the panel surfaces (with absorbed, diffuse and specular parts), with correction for the re-radiated part, does not lead to satisfactory results. Here, we analyze the solar array thermal behavior thanks to in flight information (temperatures variations along the orbit, for different sun orbital angle cases, and energy production of the array). A thermal model is constructed using thermal coefficients adjusted on these flight data (thermal capacity of the panels). An updated solar radiation pressure model is then constructed.

The Copernicus Polar Ice and Snow Topography Altimeter (CRISTAL) mission is one of six high-priority candidate missions (HPCMs) under consideration by the European Commission to enlarge the Copernicus Space Component. Together, the high-priority candidate missions fill gaps in the measurement capability of the existing Copernicus Space Component to address emerging and urgent user requirements in relation to monitoring anthropogenic CO2 emissions, polar environments, and land surfaces. The ambition is to enlarge the Copernicus Space Component with the high-priority candidate missions in the mid-2020s to provide enhanced continuity of services in synergy with the next generation of the existing Copernicus Sentinel missions. CRISTAL will carry a dual-frequency synthetic-aperture radar altimeter as its primary payload for measuring surface height and a passive microwave radiometer to support atmospheric corrections and surface-type classification. The altimeter will have interferometric capabilities at Ku-band for improved ground resolution and a second (non-interferometric) Ka-band frequency to provide information on snow layer properties. This paper outlines the user consultations that have supported expansion of the Copernicus Space Component to include the high-priority candidate missions, describes the primary and secondary objectives of the CRISTAL mission, identifies the key contributions the CRISTAL mission will make, and presents a concept – as far as it is already defined – for the mission payload.

The components of school satisfaction among eighth graders as measured by the Student Opinion Poll (SOP) and the relationships of these components with various achievement and ability scores were determined through factor analysis. Four components of school satisfaction were interpretable in meaningful terms: teacher student relationships, student peer relationships, subject matter difficulty, and subject matter interest. Knowledge of this four dimensional attitude space provided information about the achievement-attitude relationship which was contrary to previous findings in the area. For example, school satisfaction should be considered in terms of the specific components; schools should not attribute student satisfaction to personality alone; and, finally, certain components of school satisfaction are significantly related to achievement and ability and do significantly increase the multiple correlation between ability and achievement. Further research is needed to better define the nature of these school satisfaction components and to discover their antecedents. (Author/PR)

A study was designed to determine (1) differences in ethnic prejudice between 43 student teachers in early childhood education, 124 in elementary, and 195 in secondary; (2) how prejudice toward Negroes differs from that toward other ethnic groups; and (3) the relationship of ethnic prejudice to various student teaching behavior characteristics. Student teachers were given Bogardus' Ethnic Distance Scale and Hinckley's Attitude Toward the Negro Scale to measure prejudice and a semantic differential scale to assess eight characteristics of teaching (such as rigidity and conformity) hypothesized to be related to prejudice. Content analyses of supervisor reports provided information about each student's behavior with regard to 22 characteristics (e.g., enthusiasm, self-confidence, adaptability). Analysis of variance, t test, and correlational procedures were used to derive the findings. No significant differences were found between the three groups. Prejudice toward Negroes was found to be greater than toward other ethnic groups. Correlations indicated that students rated high on presentation-communication, enthusiasm, professional attitude, and sense of humor evidenced less prejudice than others, and those who had difficulty assuming responsibility and accepting constructive criticism evidenced significantly more prejudice than others. (JS)