scholarly journals Continuing the MODIS Dark Target Aerosol Time Series with VIIRS

2020 ◽  
Vol 12 (2) ◽  
pp. 308 ◽  
Author(s):  
Virginia Sawyer ◽  
Robert C. Levy ◽  
Shana Mattoo ◽  
Geoff Cureton ◽  
Yingxi Shi ◽  
...  
Keyword(s):  
Near Infrared ◽  
Infrared Imaging ◽  
Retrieval Algorithm ◽  
Spatial And Temporal Variability ◽  
Imaging Spectrometer ◽  
Standard Data ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Infrared Wavelengths ◽  
Good Agreement

For reflected sunlight observed from space at visible and near-infrared wavelengths, particles suspended in Earth’s atmosphere provide contrast with vegetation or dark water at the surface. This is the physical motivation for the Dark Target (DT) aerosol retrieval algorithm developed for the Moderate Resolution Imaging Spectrometer (MODIS). To extend the data record of aerosol optical depth (AOD) beyond the expected 20-year lifespan of the MODIS sensors, DT must be adapted for other sensors. A version of the DT AOD retrieval for the Visible Infrared Imaging Radiometer Suite (VIIRS) on the Suomi-National Polar-Orbiting Partnership (SNPP) is now mature enough to be released as a standard data product, and includes some upgraded features from the MODIS version. Differences between MODIS Aqua and VIIRS SNPP lead to some inevitable disagreement between their respective AOD measurements, but the offset between the VIIRS SNPP and MODIS Aqua records is smaller than the offset between those of MODIS Aqua and MODIS Terra. The VIIRS SNPP retrieval shows good agreement with ground-based measurements. For most purposes, DT for VIIRS SNPP is consistent enough and in close enough agreement with MODIS to continue the record of satellite AOD. The reasons for the offset from MODIS Aqua, and its spatial and temporal variability, are investigated in this study.

scholarly journals The short life of the volcanic island New Late’iki (Tonga) analyzed by multi-sensor remote sensing data

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Simon Plank ◽  
Francesco Marchese ◽  
Nicola Genzano ◽  
Michael Nolde ◽  
Sandro Martinis
Keyword(s):  
Infrared Imaging ◽  
Rapid Change ◽  
Monitoring Network ◽  
Remote Sensing Data ◽  
Volcanic Island ◽  
Imaging Spectrometer ◽  
Remote Areas ◽  
Moderate Resolution ◽  
Satellite Sensors ◽  
Resolution Imaging

AbstractSatellite-based Earth observation plays a key role for monitoring volcanoes, especially those which are located in remote areas and which very often are not observed by a terrestrial monitoring network. In our study we jointly analyzed data from thermal (Moderate Resolution Imaging Spectrometer MODIS and Visible Infrared Imaging Radiometer Suite VIIRS), optical (Operational Land Imager and Multispectral Instrument) and synthetic aperture radar (SAR) (Sentinel-1 and TerraSAR-X) satellite sensors to investigate the mid-October 2019 surtseyan eruption at Late’iki Volcano, located on the Tonga Volcanic Arc. During the eruption, the remains of an older volcanic island formed in 1995 collapsed and a new volcanic island, called New Late’iki was formed. After the 12 days long lasting eruption, we observed a rapid change of the island’s shape and size, and an erosion of this newly formed volcanic island, which was reclaimed by the ocean two months after the eruption ceased. This fast erosion of New Late’iki Island is in strong contrast to the over 25 years long survival of the volcanic island formed in 1995.

Rapid locating of fire points from Formosat-2 high spatial resolution imagery: example of the 2007 California wildfire

2009 ◽  
Vol 18 (4) ◽  
pp. 415 ◽  
Author(s):  
Cheng-Chien Liu ◽  
An-Ming Wu ◽  
Sheng-Yun Yen ◽  
Chiung-Huei Huang
Keyword(s):  
Spatial Resolution ◽  
Near Infrared ◽  
High Spatial Resolution ◽  
Burned Area ◽  
Infrared Band ◽  
Imaging Spectrometer ◽  
Modis Image ◽  
Local Spatial Statistics ◽  
Moderate Resolution ◽  
Resolution Imaging

We report the rapid response of Formosat-2 to locate the fire points in the 2007 California wildfire. After examining the Moderate Resolution Imaging Spectrometer (MODIS) image taken and released on 23 October 2007, we used the agility of Formosat-2 to take high spatial resolution images of the wildfire front on its next overpass of the newly burned area. By calculating the local spatial statistics of the near-infrared band, fire points with a scale of a few metres can be accurately identified on the 2-m pan-sharpened Formosat-2 image. The present work suggests that the synergistic operation of MODIS and Formosat-2 would enable the rapid locating of fire points during wildfires.

scholarly journals A Long-Term Passive Microwave Snowoff Record for the Alaska Region 1988–2016

2020 ◽  
Vol 12 (1) ◽  
pp. 153
Author(s):  
Caleb G. Pan ◽  
Peter B. Kirchner ◽  
John S. Kimball ◽  
Jinyang Du
Keyword(s):  
Passive Microwave ◽  
Spatial And Temporal Variability ◽  
Permafrost Degradation ◽  
Imaging Spectrometer ◽  
Hydrologic Processes ◽  
Mapping System ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Boreal Landscapes

Snowoff (SO) date—defined as the last day of observed seasonal snow cover—is an important governor of ecologic and hydrologic processes across Alaska and Arctic-Boreal landscapes; however, our understanding and capacity for the monitoring of spatial and temporal variability in the SO date is still lacking. In this study, we present a 6.25 km spatially gridded passive microwave (PMW) SO data record, complimenting current Alaskan SO records from Moderate Resolution Imaging Spectrometer (MODIS) and Landsat, but extending the SO record an additional 13 years. The PMW SO record was validated against in situ snow depth observations and showed favorable accuracy (0.66–0.92 mean correlations; 2–10 day mean absolute errors) for the major climate regions of Alaska. The PMW SO results were also within 10 days of finer spatial scale SO observational records, including Interactive Multisensor Snow and Ice Mapping System (IMS), MODIS, and Landsat, for a majority (75%) of Alaska. However, the PMW record showed a general SO delay at higher elevations and across the Alaska North Slope, and earlier SO in the Alaska interior and southwest regions relative to the other SO records. Overall, we assign an uncertainty +/−11 days to the PMW SO. The PMW SO record benefits from the near-daily temporal fidelity of underlying brightness temperature (Tb) observations and reveals a mean regional trend in earlier SO timing (−0.39 days yr−1), while significant (p < 0.1) SO trend areas encompassed 11% of the Alaska domain and ranged from −0.11 days yr−1 to −1.31 days yr−1 over the 29-year satellite record. The observed SO dates also showed anomalous early SO dates during markedly warm years. Our results clarify the pattern and rate of SO changes across Alaska, which are interactive with global warming and contributing to widespread permafrost degradation, changes in regional hydrology, ecosystems, and associated services. Our results also provide a robust means for SO monitoring from satellite PMW observations with similar precision as more traditional and finer scale observations.

scholarly journals MISR empirical stray light corrections in high-contrast scenes

2015 ◽  
Vol 8 (7) ◽  
pp. 2927-2943 ◽  
Author(s):  
J. A. Limbacher ◽  
R. A. Kahn
Keyword(s):  
Near Infrared ◽  
Stray Light ◽  
Retrieval Algorithm ◽  
High Contrast ◽  
Validation Data ◽  
Modis Imagery ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Terra Satellite

Abstract. We diagnose the potential causes for the Multi-angle Imaging SpectroRadiometer's (MISR) persistent high aerosol optical depth (AOD) bias at low AOD with the aid of coincident MODerate-resolution Imaging Spectroradiometer (MODIS) imagery from NASA's Terra satellite. Stray light in the MISR instrument is responsible for a large portion of the high AOD bias in high-contrast scenes, such as broken-cloud scenes that are quite common over ocean. Discrepancies among MODIS and MISR nadir-viewing blue, green, red, and near-infrared images are used to optimize seven parameters individually for each wavelength, along with a background reflectance modulation term that is modeled separately, to represent the observed features. Independent surface-based AOD measurements from the AErosol RObotic NETwork (AERONET) and the Marine Aerosol Network (MAN) are compared with MISR research aerosol retrieval algorithm (RA) AOD retrievals for 1118 coincidences to validate the corrections when applied to the nadir and off-nadir cameras. With these corrections, plus the baseline RA corrections and enhanced cloud screening applied, the median AOD bias for all data in the mid-visible (green, 558 nm) band decreases from 0.006 (0.020 for the MISR standard algorithm (SA)) to 0.000, and the RMSE decreases by 5 % (27 % compared to the SA). For AOD558 nm < 0.10, which includes about half the validation data, 68th percentile absolute AOD558 nm errors for the RA have dropped from 0.022 (0.034 for the SA) to < 0.02 (~ 0.018).

scholarly journals MODIS observed increase in duration and spatial extent of sediment plumes in Greenland fjords

2013 ◽  
Vol 7 (6) ◽  
pp. 6101-6141 ◽  
Author(s):  
B. Hudson ◽  
I. Overeem ◽  
D. McGrath ◽  
J. P. M. Syvitski ◽  
A. Mikkelsen ◽  
...  
Keyword(s):  
Greenland Ice Sheet ◽  
Sediment Concentration ◽  
Spatial Extent ◽  
Retrieval Algorithm ◽  
River Plumes ◽  
Imaging Spectrometer ◽  
Complex Processes ◽  
Meltwater Runoff ◽  
Moderate Resolution ◽  
Resolution Imaging

Abstract. We test the hypothesis that increased meltwater runoff from the Greenland Ice Sheet (GrIS) has elevated the suspended sediment concentration (SSC) of six river plumes in three fjords in southwest Greenland. A~SSC retrieval algorithm was developed using the largest in situ SSC dataset for Greenland known and applied to all cloud free NASA Moderate Resolution Imaging Spectrometer (MODIS) reflectance values in the Terra image archive (2000 to 2012). Melt-season mean plume SSC has not increased as anticipated, with the exception of one river. However, positive statistically significant trends involving metrics that described the duration and the spatial extent of river plumes were observed in many locations. Zones of sediment concentration > 50 mg L−1 expanded in three river plumes, with potential consequences for biological productivity. The high SSC cores of river plumes (> 250 mg L−1) expanded in one-third of study locations. When data from study rivers was aggregated, higher volumes of runoff were associated with higher melt-season mean plume SSC values, but this relationship did not hold for individual rivers. High spatial variability between proximal plumes highlights the complex processes operating in Greenland's glacio-fluvial-fjord systems.

Impact of aerosol on air temperature in Baghdad

2017 ◽  
Vol 2 (6) ◽  
Author(s):  
Yaseen Kadhim Abbas Al-Timimi ◽  
Ali Challob Khraibet
Keyword(s):  
Temperature Variation ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Air Temperature ◽  
Strong Correlation ◽  
Imaging Spectrometer ◽  
Moderate Resolution ◽  
Resolution Imaging

Aerosol Optical Depth (AOD) is the measure of aerosol distributed with a Column of air from earth’s surface to the top of atmosphere, in this study, temperature variation of aerosol optical depth (AOD) in Baghdad was analyzed Moderate Resolution Imaging Spectrometer (MODIS) from Terra and its relationship with temperature for the period 2003 – 2015 were examined. The highest values for mean seasonal AOD were observed in spring and summer and the maximum AOD values ranged from 0.50 to 0.58 by contrast minimum AOD values ranging from 0.30 to 0.41 were found in winter and autumn. Results of study also showed that the temperature (max., min., mean air temperature and DTR) have a strong correlation with AOD (0.82, 0.83, 0.82 and 0.65) respectively.

scholarly journals Real-Time Detection of Daytime and Night-Time Fire Hotspots from Geostationary Satellites

2021 ◽  
Vol 13 (9) ◽  
pp. 1627
Author(s):  
Chermelle B. Engel ◽  
Simon D. Jones ◽  
Karin J. Reinke
Keyword(s):  
Real Time ◽  
Infrared Imaging ◽  
Night Time ◽  
Clear Link ◽  
Radiative Power ◽  
Biogeographical Region ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Fire Radiative Power

This paper introduces an enhanced version of the Biogeographical Region and Individual Geostationary HHMMSS Threshold (BRIGHT) algorithm. The algorithm runs in real-time and operates over 24 h to include both daytime and night-time detections. The algorithm was executed and tested on 12 months of Himawari-8 data from 1 April 2019 to 31 March 2020, for every valid 10-min observation. The resulting hotspots were compared to those from the Visible Infrared Imaging Radiometer Suite (VIIRS) and the Moderate Resolution Imaging Spectroradiometer (MODIS). The modified BRIGHT hotspots matched with fire detections in VIIRS 96% and MODIS 95% of the time. The number of VIIRS and MODIS hotspots with matches in the coincident modified BRIGHT dataset was lower (at 33% and 46%, respectively). This paper demonstrates a clear link between the number of VIIRS and MODIS hotspots with matches and the minimum fire radiative power considered.

scholarly journals Global and regional evaluation of over-land spectral aerosol optical depth retrievals from SeaWiFS

2012 ◽  
Vol 5 (2) ◽  
pp. 2169-2220 ◽  
Author(s):  
A. M. Sayer ◽  
N. C. Hsu ◽  
C. Bettenhausen ◽  
M.-J. Jeong ◽  
B. N. Holben ◽  
...  
Keyword(s):  
North America ◽  
Aerosol Optical Depth ◽  
Optical Depth ◽  
Field Of View ◽  
Wide Field ◽  
Imaging Spectrometer ◽  
Wide Field Of View ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Multiangle Imaging

Abstract. This study evaluates a new spectral aerosol optical depth (AOD) dataset derived from Sea-viewing Wide Field-of-view Sensor (SeaWiFS) measurements over land. First, the data are validated against Aerosol Robotic Network (AERONET) direct-sun AOD measurements, and found to compare well on a global basis. If only data with the highest quality flag are used, the correlation is 0.86 and 72% of matchups fall within an expected absolute uncertainty of 0.05 + 20% (for the wavelength of 550 nm). The quality is similar at other wavelengths and stable over the 13-yr (1997–2010) mission length. Performance tends to be better over vegetated, low-lying terrain with typical AOD of 0.3 or less, such as found over much of North America and Eurasia. Performance tends to be poorer for low-AOD conditions near backscattering geometries, where SeaWiFS overestimates AOD, or optically-thick cases of absorbing aerosol, where SeaWiFS tends to underestimate AOD. Second, the SeaWiFS data are compared with midvisible AOD derived from the Moderate Resolution Imaging Spectrometer (MODIS) and Multiangle Imaging Spectroradiometer (MISR). All instruments show similar spatial and seasonal distributions of AOD, although there are regional and seasonal offsets between them. At locations where AERONET data are available, these offsets are largely consistent with the known validation characteristics of each dataset. With the results of this study in mind, the SeaWiFS over-land AOD record is suitable for quantitative scientific use.

scholarly journals Using Moderate Resolution Imaging Spectrometer (MODIS) to calibrate advanced very high resolution radiometer reflectance channels

2002 ◽  
Vol 107 (D23) ◽  
pp. AAC 11-1-AAC 11-10 ◽  
Author(s):  
Andrew K. Heidinger ◽  
Changyong Cao ◽  
Jerry T. Sullivan
Keyword(s):  
High Resolution ◽  
Imaging Spectrometer ◽  
Moderate Resolution ◽  
Resolution Imaging ◽  
Very High
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