MODIS instrument operation and calibration improvements

Xiong, Xiaoxiong; Angal, Amit; Madhavan, Sriharsha; Link, Daniel; Geng, Xu; Wenny, Brian N.; Wu, Aisheng; Chen, Hongda; Salomonson, V. V.

doi:10.1109/igarss.2014.6946693

Cited by 4 publications

(2 citation statements)

References 7 publications

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“…One may be concerned that the trend may be caused by systematic errors, particularly the aging thermal sensor and the drift in the overpass time over years. First, the change in MODIS response for thermal bands can be taken into account by scheduled on-orbit calibration using an onboard blackbody [Xiong et al, 2014], Journal of Geophysical Research: Atmospheres 10.1002/2015JD024354 whose temperature has exhibited excellent long-term stability since 2000: the drift was less than 0.04 K over 14 years [Xiong et al, 2014].…”

Section: Systematic Errorsmentioning

confidence: 99%

Time series decomposition of remotely sensed land surface temperature and investigation of trends and seasonal variations in surface urban heat islands

et al. 2016

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Previous time series methods have difficulties in simultaneous characterization of seasonal, gradual, and abrupt changes of remotely sensed land surface temperature (LST). This study proposed a model to decompose LST time series into trend, seasonal, and noise components. The trend component indicates long-term climate change and land development and is described as a piecewise linear function with iterative breakpoint detection. The seasonal component illustrates annual insolation variations and is modeled as a sinusoidal function on the detrended data. This model is able to separate the seasonal variation in LST from the long-term (including gradual and abrupt) change. Model application to nighttime Moderate Resolution Imaging Spectroradiometer (MODIS)/LST time series during 2000-2012 over Beijing yielded an overall root-mean-square error of 1.62 K between the combination of the decomposed trend and seasonal components and the actual MODIS/LSTs. LST decreased (~À0.086 K/yr, p < 0.1) in 53% of the study area, whereas it increased with breakpoints in 2009 (~0.084 K/yr before and~0.245 K/yr after 2009) between the fifth and sixth ring roads. The decreasing trend was stronger over croplands than over urban lands (p < 0.05), resulting in an increasing trend in surface urban heat island intensity (SUHII, 0.022 ± 0.006 K/yr). This was mainly attributed to the trends in urban-rural differences in rainfall and albedo. The SUHII demonstrated a concave seasonal variation primarily due to the seasonal variations of urban-rural differences in temperature cooling rate (related to canyon structure, vegetation, and soil moisture) and surface heat dissipation (affected by humidity and wind).

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Section: Systematic Errorsmentioning

confidence: 99%

Time series decomposition of remotely sensed land surface temperature and investigation of trends and seasonal variations in surface urban heat islands

et al. 2016

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“…Near-monthly roll maneuvers allow the moon to be viewed through the instrument space view (SV) port. Measurement of the moon provides an alternate source of calibration for the RSB [4][5][6][7][8][9][10].…”

Section: On-orbit Calibration Activitiesmentioning

confidence: 99%

Status of MODIS spatial and spectral characterization and performance

2016

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Since launch, both Terra and Aqua MODIS instruments have continued to operate and make measurements of the earth's top of atmospheric (TOA) radiances and reflectance. MODIS collects data in 36 spectral bands covering wavelengths from 0.41 to 14.4 m. These spectral bands and detectors are located on four focal plane assemblies (FPAs). MODIS on-board calibrators (OBC) include a spectro-radiometric calibration assembly (SRCA), which was designed to characterize and monitor sensor spatial and spectral performance, such as onorbit changes in the band-to-band registration (BBR), modulation transfer function (MTF), spectral band center wavelengths (CW) and bandwidths (BW). In this paper, we provide a status update of MODIS spatial and spectral characterization and performance, following a brief description of SRCA functions and on-orbit calibration activities. Sensor spatial and spectral performance parameters derived from SRCA measurements are introduced and discussed. Results show that on-orbit spatial performance has been very stable for both Terra and Aqua MODIS instruments. The large BBR shifts in Aqua MODIS, an issue identified pre-launch, have remained the same over its entire mission. On-orbit changes in CW and BW are less than 0.5 nm and 1 nm, respectively, for most VIS/NIR spectral bands of both instruments.

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