Terra MODIS band 2 electronic crosstalk: cause, impact, and mitigation

IEEE Trans. Geosci. Remote Sensing

Xiong

Madhavan

et al. 2014

The MODerate-resolution Imaging Spectroradiometer (MODIS) is one of the primary instruments in the NASA Earth Observing System (EOS). The first MODIS instrument was launched in December, 1999 on-board the Terra spacecraft. MODIS has 36 bands, covering a wavelength range from 0.4 µm to 14.4 µm. MODIS band 27 (6.72 µm) is a water vapor band, which is designed to be insensitive to Earth surface features. In recent Earth View (EV) images of Terra band 27, surface feature contamination is clearly seen and striping has become very pronounced. In this paper, it is shown that band 27 is impacted by electronic crosstalk from bands 28-30. An algorithm using a linear approximation is developed to correct the crosstalk effect. The crosstalk coefficients are derived from Terra MODIS lunar observations. They show that the crosstalk is strongly detector dependent and the crosstalk pattern has changed dramatically since launch. The crosstalk contributions are positive to the instrument response of band 27 early in the mission but became negative and much larger in magnitude at later stages of the mission for most detectors of the band. The algorithm is applied to both Black Body (BB) calibration and MODIS L1B products. With the crosstalk effect removed, the calibration coefficients of Terra MODIS band 27 derived from the BB show that the detector differences become smaller. With the algorithm applied to MODIS L1B products, the Earth surface features are significantly removed and the striping is substantially reduced in the images of the band. The approach developed in this report for removal of the electronic crosstalk effect can be applied to other MODIS bands if similar crosstalk behaviors occur.

Section: Crosstalk Correction Algorithmsmentioning

confidence: 99%

mentioning

confidence: 99%

See 1 more Smart Citation

Terra MODIS Band 27 Electronic Crosstalk Effect and Its Removal

IEEE Trans. Geosci. Remote Sensing

Xiong

Madhavan

et al. 2014

“…Nevertheless, it is both possible and essential to establish a relationship describing the crosstalk phenomena and subsequently prescribing its correction. As a first-order approximation, Sun et al [5,6,[15][16][17] …”

Section: Crosstalk Correction Algorithmmentioning

confidence: 99%

“…Especially in a clear scene with sharp edges, a ghost image can be distinctive and pronounced. The Moon in particular has been shown to be an excellent natural point-like target to exhibit this effect and has a similar radiance level as the Earth's surface, therefore, within the response range of the instrument, it enables an effective analysis [14][15][16][17]. From the regularly scheduled lunar observations, crosstalk effect in Aqua MODIS can be identified and its change over time can be quantified.…”

Section: Introductionmentioning

confidence: 99%

Electronic Crosstalk in Aqua MODIS Long-Wave Infrared Photovoltaic Bands

Wang

2016

Remote Sensing

Recent investigations have discovered that Terra MODerate-resolution Imaging Spectroradiometer (MODIS) long-wave infrared (LWIR) photovoltaic (PV) bands, bands 27-30, have strong crosstalk among themselves. The linear model developed to test the electronic crosstalk effect was instrumental in the first discovery of the effect in Terra MODIS band 27, and through subsequent investigations the model and the correction algorithm were tested further and established to be correct. It was shown that the correction algorithm successfully mitigated the anomalous features in the calibration coefficients as well as the severe striping and the long-term drift in the Earth view (EV) retrievals for the affected Terra bands. Here, the examination into Aqua MODIS using the established methodology confirms the existence of significant crosstalk contamination in its four LWIR PV, although the finding shows the overall effect to be of lesser degree. The crosstalk effect is characterized and the crosstalk correction coefficients are derived for all four Aqua LWIR PV bands via analysis of signal contamination in the lunar imagery. Sudden changes in the crosstalk contamination are clearly seen, as also in the Terra counterparts in previous investigations. These sudden changes are consistent with the sudden jumps observed in the linear calibration coefficients for many years, thus this latest finding provides an explanation to the long-standing but unexplained anomalies in the calibration coefficients of the four Aqua LWIR bands. It is also shown that the crosstalk contamination for these bands are of similar level for the two MODIS instruments in the early mission that can lead to as much as 2 K increase in brightness temperature for the affected bands, thus demonstrating significant impact on the science results already started at the early going. As Aqua MODIS is a legacy sensor, the crosstalk correction to its LWIR PV bands will be important to remove the impact of the crosstalk contamination from its calibration results and the associated science products.

Crosstalk Effect and Its Mitigation in Aqua MODIS Middle‐Wave Infrared Bands

Earth and Space Science

Guenther

Wang

2019

The MODerate‐resolution Imaging Spectroradiometer (MODIS) has 36 bands, among which 6, bands 20–25, are middle‐wave infrared (MWIR) bands, covering a wavelength range from approximately 3.750 to 4.515 μm. Significant crosstalk effect in Aqua MODIS MWIR bands was found prelaunch and confirmed on‐orbit early in the mission. In this paper, the crosstalk effect in these bands is carefully investigated and quantitatively characterized using the instrument's scheduled lunar observations. The crosstalk correction algorithm that we have developed in our previous work is applied to all levels including black body calibration and L1B EV retrievals to mitigate the crosstalk effect in the bands. We show significant crosstalk contaminations among all MWIR bands and also show that these bands have significant crosstalk contaminations from the shortwave infrared bands. We demonstrate that the crosstalk effect has significant impact on onboard black body calibration as well as on EV retrievals. For L1B EV retrievals, these crosstalk effects induce significant radiometric bias as well as strong striping. The radiometric bias is larger than 1.8 K for all detectors of the 4.47‐μm band (band 24) for typical scene. Aqua MODIS band 24 detector 1 is most strongly impacted by crosstalk and has a bias that may be as large as 10 K. The crosstalk correction successfully mitigates the striping in the EV images and improves the accuracy of the EV retrievals in the MWIR bands.