Preliminary evaluation of S‐NPP VIIRS aerosol optical thickness

Hongqing, Liu; Remer, L. A.; Huang, Jingfeng; Huang, H. C.; Kondragunta, Shobha; László, István; Oo, M. M.; Jackson, John M.

doi:10.1002/2013jd020360

Cited by 116 publications

(124 citation statements)

References 59 publications

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“…According to suggestions from other research groups [16,22,24], data matching was performed with the following rules. First, the mean AOD was averaged when at least 20% of the pixels fell within the sampling box.…”

Section: Comparison and Verification Of Methodsmentioning

confidence: 99%

“…Sun photometer data acquired within 30 min of the satellite overpass times were collected from 2014 to 2016. The data provided by a sun photometer did not have the 550 nm channel, and AODs at 550 nm were calculated by linear interpolation at a log scale from two measurements with adjacent wavelengths [16]. To show how accurately the satellite AOD matched the evaluation datasets, the following metrics were applied.…”

Section: Comparison and Verification Of Methodsmentioning

confidence: 99%

“…This instrument is a scanning radiometer that can extend and improve upon the heritage of AVHRR and MODIS [16]. VIIRS aerosol retrieval is performed at the pixel level and produces aerosol products with a spatial resolution of 0.75 km [31].…”

Section: Viirs Datamentioning

confidence: 99%

“…VIIRS aerosol retrieval is performed at the pixel level and produces aerosol products with a spatial resolution of 0.75 km [31]. The product of this process, known as IP, is then aggregated and designated as an Environmental Data Record (EDR) reported at 6 km (8 × 8 pixels) resolution at nadir [16]. In this work, we evaluated VIIRS AOD550s at IP level.…”

Section: Viirs Datamentioning

confidence: 99%

“…AOD550s are the most important aerosol parameters used by models and other community-wide applications. Quality assurance is applied at IP levels, with the resulting flags indicating the confidence of the retrievals as described in detail in [16]. For the current study, a three-year (from 1 January 2014 to 31 December 2016) dataset of AOD from VIIRS IP with quality flag = 0 (good), was analyzed to evaluate the performance of VIIRS in Wuhan.…”

Section: Viirs Datamentioning

confidence: 99%

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Validation of VIIRS AOD through a Comparison with a Sun Photometer and MODIS AODs over Wuhan

et al. 2017

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Visible Infrared Imaging Radiometer Suite (VIIRS) is a next-generation polar-orbiting operational environmental sensor with a capability for global aerosol observations. A comprehensive validation of VIIRS products is significant for improving product quality, assessing environment quality for human life, and studying regional climate change. In this study, three-year (from 1 January 2014 to 31 December 2016) records of VIIRS Intermediate Product (IP) data and Moderate Resolution Imaging Spectroradiometer (MODIS) retrievals on aerosol optical depth (AOD) at 550 nm were evaluated by comparing them to ground sun photometer measurements over Wuhan. Results indicated that VIIRS IP retrievals were underestimated by 5% for the city. A comparison of VIIRS IP retrievals and ground sun photometer measurements showed a lower R 2 of 0.55 (0.79 for Terra-MODIS and 0.76 for Aqua-MODIS), with only 52% of retrievals falling within the expected error range established by MODIS over land (i.e., ±(0.05 + 0.15AOD)). Bias analyses with different Ångström exponents (AE) demonstrated that land aerosol model selection of the VIIRS retrieval over Wuhan was appropriate. However, the larger standard deviations (i.e., uncertainty) of VIIRS AODs than MODIS AODs could be attributed to the less robust retrieval algorithm. Monthly variations displayed largely underestimated AODs of VIIRS in winter, which could be caused by a large positive bias in surface reflectance estimation due to the sparse vegetation and greater surface brightness of Wuhan in this season. The spatial distribution of VIIRS and MODIS AOD observations revealed that the VIIRS IP AODs over high-pollution areas (AOD > 0.8) with sparse vegetation were underestimated by more than 20% in Wuhan, and 40% in several regions. Analysis of several clear rural areas (AOD < 0.2) with native vegetation indicated an overestimation of about 20% in the northeastern region of the city. These findings showed that the VIIRS IP AOD at 550 nm can provide a solid dataset with a high resolution (750 m) for quantitative scientific investigations and environmental monitoring over Wuhan. However, the performance of dark target algorithms in VIIRS was associated with aerosol types and ground vegetation conditions.

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Section: Comparison and Verification Of Methodsmentioning

confidence: 99%

Section: Comparison and Verification Of Methodsmentioning

confidence: 99%

Section: Viirs Datamentioning

confidence: 99%

Section: Viirs Datamentioning

confidence: 99%

Section: Viirs Datamentioning

confidence: 99%

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Validation of VIIRS AOD through a Comparison with a Sun Photometer and MODIS AODs over Wuhan

et al. 2017

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S-NPP VIIRS thermal emissive bands on-orbit calibration and performance

Efremova

McIntire

Moyer

et al. 2014

J. Geophys. Res. Atmos.

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Presented is an assessment of the on-orbit radiometric performance of the thermal emissive bands (TEB) of the Suomi National Polar-orbiting Partnership (S-NPP) Visible Infrared Imaging Radiometer Suite (VIIRS) instrument based on data from the first 2 years of operations-from 20 January 2012 to 20 January 2014. The VIIRS TEB are calibrated on orbit using a V-grooved blackbody (BB) as a radiance source. Performance characteristics trended over the life of the mission include the F factor-a measure of the gain change of the TEB detectors; the Noise Equivalent differential Temperature (NEdT)-a measure of the detector noise; and the detector offset and nonlinear terms trended at the quarterly performed BB warm-up cool-down cycles. We find that the BB temperature is well controlled and stable within the 30 mK requirement. The F factor trends are very stable and showing little degradation (within 0.8%). The offsets and nonlinearity terms are also without noticeable drifts. NEdT is stable and does not show any trend. Other TEB radiometric calibration-related activities discussed include the on-orbit assessment of the response versus scan-angle functions and an approach to improve the M13 low-gain calibration using onboard lunar measurements. We conclude that all the assessed parameters comply with the requirements, and the TEB provide radiometric measurements with the required accuracy.

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CALIPSO inferred most probable heights of global dust and smoke layers

et al. 2015

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The vertical location of aerosol layers is critical for determining predominance of aerosol radiative and microphysical effects in aerosol-cloud-precipitation-climate interaction. The spaceborne lidar system, the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observations (CALIPSO), provides an unprecedented opportunity to observe vertical distributions of global aerosol layers. In this study we examine the most probable height (MPH) of dust and smoke layers, which are calculated either from aerosol occurrence frequency (OF) in vertical feature mask or aerosol extinction profile. The study focuses on six high-aerosol-loading regions where aerosols are of great interest in a range of scientific topics: Saharan Air Layer (SAL) over Tropical Atlantic, West African Monsoon region (WAM), Southeast Atlantic Ocean (SAO), Southeast Asia (SEA) and South China Sea, Amazon (AMZ), and Northwestern Pacific (NWP). The analysis revealed interesting spatial and seasonal variability of different vertical mixture features over these regions: seasonal migration of dust layers over SAL, separation and mixture of dust and smoke layers over WAM and NWP, and smoke layer above clouds over SAO, SEA, and AMZ. Results also indicated that the OF-based MPH tends to be much higher than the aerosol optical depth (AOD)-based MPH, owing to the predominating near-surface sources. Within the same vertical resolution grid of CALIPSO, aerosols are found with higher OF at higher levels but AOD tends to increase toward lower levels, because most aerosol sources are near the surface and the aerosol layers transported to high altitudes are generally much more diluted over larger spatial domain than those near the surface.

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Preliminary evaluation of S‐NPP VIIRS aerosol optical thickness

Cited by 116 publications

References 59 publications

Validation of VIIRS AOD through a Comparison with a Sun Photometer and MODIS AODs over Wuhan

Validation of VIIRS AOD through a Comparison with a Sun Photometer and MODIS AODs over Wuhan

S-NPP VIIRS thermal emissive bands on-orbit calibration and performance

CALIPSO inferred most probable heights of global dust and smoke layers

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