Characterization of the South Atlantic Anomaly

Nasuddin, Khairul Afifi; Abdullah, Mardina; Hamid, Nurul Shazana Abdul

doi:10.5194/npg-2018-51

Cited by 1 publication

(1 citation statement)

References 23 publications

(29 reference statements)

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“…Typically, the SAA is situated at an altitude of 200 km to 800 km over the Earth's surface (Nasuddin et al, 2018). A significant increase of dark signal levels in the region of the SAA has been observed on the CCDs of the Hubble Space Telescope which is operated at an altitude of 540 km (Kimble et al, 2000).…”

Section: Dark Current Signals and Anomaliesmentioning

confidence: 99%

Characterization of dark current signal measurements of the ACCDs used on-board the Aeolus satellite

Weiler¹,

Kanitz²,

Wernham³

et al. 2020

Preprint

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Abstract. Already shortly after the successful launch of the European Space Agency satellite Aeolus in August 2018, it turned out that dark current signal anomalies of single pixels (so-called hot pixels) on the Accumulation-Charge-Coupled Devices (ACCDs) of the Aeolus detectors detrimentally impact the quality of the aerosol and wind products potentially leading to wind errors of up to 4 m/s. This paper provides a detailed characterization of the hot pixels which occurred during the first one and a half years in orbit. The hot pixels are classified according to their characteristics to discuss their impact on wind measurements. Furthermore, mitigation approaches for the wind retrieval are presented and potential root causes for the hot pixel occurrence are discussed. The analysis of the dark current signal anomalies reveals a large variety of anomalies ranging from pixels with Random Telegraph Signal (RTS)-like characteristics to pixels with sporadic shifts in the median dark current signal. Moreover, the results indicate that the number of hot pixels has almost linearly increased during the observing period between 2018-09-02 until 2020-05-20 with 6 % of the ACCD pixels affected in total at the end of the period leading to 9.5 % at the end of mission lifetime. This work introduces dedicated instrument calibration modes and ground processors which allowed for a correction shortly after a hot pixel occurrence. The achieved performance with this approach avoids risky adjustments to the inflight hardware operation. It is demonstrated that the success of the correction scheme varies depending on the characteristics of each hot pixel itself. With the herein presented categorization, it is shown that multi-level RTS pixels with high fluctuation are the biggest challenge for the hot pixel correction scheme. Despite a detailed analysis in this framework, no conclusion could be drawn about the root cause of the hot pixel issue.

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Section: Dark Current Signals and Anomaliesmentioning

confidence: 99%