scholarly journals Efficient and Flexible Aggregation and Distribution of MODIS Atmospheric Products Based on Climate Analytics as a Service Framework

2021 ◽  
Vol 13 (17) ◽  
pp. 3541
Author(s):  
Jianyu Zheng ◽  
Xin Huang ◽  
Supriya Sangondimath ◽  
Jianwu Wang ◽  
Zhibo Zhang
Keyword(s):  
Vital Role ◽  
Parallel Execution ◽  
Observation System ◽  
Single Node ◽  
Spectral Bands ◽  
Service Oriented ◽  
Moderate Resolution ◽  
Level 3 ◽  
Earth Observation System ◽  
Moderate Resolution Imaging Spectroradiometer

MODIS (Moderate Resolution Imaging Spectroradiometer) is a key instrument onboard NASA’s Terra (launched in 1999) and Aqua (launched in 2002) satellite missions as part of the more extensive Earth Observation System (EOS). By measuring the reflection and emission by the Earth-Atmosphere system in 36 spectral bands from the visible to thermal infrared with near-daily global coverage and high-spatial-resolution (250 m ~ 1 km at nadir), MODIS is playing a vital role in developing validated, global, interactive Earth system models. MODIS products are processed into three levels, i.e., Level-1 (L1), Level-2 (L2) and Level-3 (L3). To shift the current static and “one-size-fits-all” data provision method of MODIS products, in this paper, we propose a service-oriented flexible and efficient MODIS aggregation framework. Using this framework, users only need to get aggregated MODIS L3 data based on their unique requirements and the aggregation can run in parallel to achieve a speedup. The experiments show that our aggregation results are almost identical to the current MODIS L3 products and our parallel execution with 8 computing nodes can work 88.63 times faster than a serial code execution on a single node.

scholarly journals Monthly-averaged maps of surface BRDF parameters in ten spectral bands for land and water masses

2018 ◽  
Author(s):  
Philippe Blanc ◽  
Benoit Gschwind ◽  
Lionel Ménard ◽  
Lucien Wald
Keyword(s):  
Original Data ◽  
Observation System ◽  
Creative Commons ◽  
Spectral Bands ◽  
The Usa ◽  
Moderate Resolution ◽  
Earth Observation System ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Bidirectional Reflectance Distribution

Abstract. The construction of worldwide maps of surface bidirectional reflectance distribution function (BRDF) parameters is presented. The original data stems from the National Aeronautics and Space Administration (NASA) of the USA which is making available maps of BRDF parameters that are derived from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument. The first parameter fiso describes the isotropic part of the BRDF while the two others fvol and fgeo describe the anisotropic part and are linked to the viewing and illuminating geometry. The original data has been averaged for each calendar month for the period 2004–2011 and a spatial completion of data was performed, especially in water-covered areas. The resulting complete maps are available in ten spectral bands: [459–479] nm, [545–565] nm, [620–670] nm, [400–700] nm, [841–876] nm, [1230–1250] nm, [1628–1652] nm, [2105–2155] nm, [250–5000] nm, [700–5000] nm, [250–5000] nm. The maps form a Global Earth Observation System of Systems (GEOSS) Data Collection of Open Resources for Everyone (Data-CORE) supporting the GEOSS Data Sharing Principles. They are referenced by the doi:10.23646/85d2cd5f-ccaa-482e-a4c9-b6e0c59d966c and available in NetCDF format under the Creative Commons license CC-BY.

scholarly journals Computationally Efficient Methods of Collocating Satellite, Aircraft, and Ground Observations

2009 ◽  
Vol 26 (8) ◽  
pp. 1585-1595 ◽  
Author(s):  
Frederick W. Nagle ◽  
Robert E. Holz
Keyword(s):  
Observation System ◽  
Computationally Efficient ◽  
Laptop Computer ◽  
Geometric Problem ◽  
Temporal Sampling ◽  
Wide Range ◽  
Moderate Resolution ◽  
Surface Measurements ◽  
Earth Observation System ◽  
Moderate Resolution Imaging Spectroradiometer

Abstract The usefulness of measurements from satellite-borne instruments is enhanced if these measurements can be compared to measurements from other instruments mounted aboard the same or different satellite, with measurements from aircraft, or with ground measurements. The process of associating measurements from disparate instruments and platforms is referred to as collocation. In a few cases, two instruments mounted aboard the same spacecraft have been engineered to function in tandem, but commonly this is not the case. The collocation process may then become an awkward geometric problem of finding which of many observations within one dataset corresponds to an observation in another set, possibly from another platform. This paper presents methods that can be applied to a wide range of satellite, aircraft, and surface measurements that allow for efficient collocation with measurements having varying spatial and temporal sampling. Examples of applying the methods are presented that highlight the benefits of efficient collocation. This includes identifying the occurrence of simultaneous nadir observations (SNOs); collocation of sounder, imager, and active remotely sensed measurements on the NASA Earth Observation System (EOS); and collocation of the polar orbiting imager, sounder, and microwave measurements with geostationary observations. It is possible, using an inexpensive laptop computer, to collocate Moderate Resolution Imaging Spectroradiometer (MODIS) imager observations from the Aqua satellite with geostationary observations rapidly enough to deal with these measurements in real time, making either dataset, enhanced by the other, a potentially operational product. A “tool kit” is suggested consisting of computer procedures useful in collocation.

scholarly journals Quality Assessment of PROBA-V LAI, fAPAR and fCOVER Collection 300 m Products of Copernicus Global Land Service

2020 ◽  
Vol 12 (6) ◽  
pp. 1017 ◽  
Author(s):  
Beatriz Fuster ◽  
Jorge Sánchez-Zapero ◽  
Fernando Camacho ◽  
Vicente García-Santos ◽  
Aleixandre Verger ◽  
...  
Keyword(s):  
Quality Assessment ◽  
Accuracy Assessment ◽  
Observation System ◽  
Good Precision ◽  
Area Index ◽  
Global Land ◽  
Moderate Resolution ◽  
Earth Observation System ◽  
Temporal Profiles ◽  
Absorbed Photosynthetically Active Radiation

The Copernicus Global Land Service (CGLS) provides global time series of leaf area index (LAI), fraction of absorbed photosynthetically active radiation (fAPAR) and fraction of vegetation cover (fCOVER) data at a resolution of 300 m and a frequency of 10 days. We performed a quality assessment and validation of Version 1 Collection 300 m products that were consistent with the guidelines of the Land Product Validation (LPV) subgroup of the Committee on Earth Observation System (CEOS) Working Group on Calibration and Validation (WGCV). The spatiotemporal patterns of Collection 300 m V1 LAI, fAPAR and fCOVER products are consistent with CGLS Collection 1 km V1, Collection 1 km V2 and Moderate Resolution Imagery Spectroradiometer Collection 6 (MODIS C6) products. The Collection 300 m V1 products have good precision and smooth temporal profiles, and the interannual variations are consistent with similar satellite products. The accuracy assessment using ground measurements mainly over crops shows an overall root mean square deviation of 1.01 (44.3%) for LAI, 0.12 (22.2%) for fAPAR and 0.21 (42.6%) for fCOVER, with positive mean biases of 0.36 (15.5%), 0.05 (10.3%) and 0.16 (32.2%), respectively. The products meet the CGLS user accuracy requirements in 69.1%, 62.5% and 29.7% of the cases for LAI, fAPAR and fCOVER, respectively. The CGLS will continue the production of Collection 300 m V1 LAI, fAPAR and fCOVER beyond the end of the PROBA-V mission by using Sentinel-3 OLCI as input data.

scholarly journals Optimizing CALIPSO Saharan dust retrievals

2013 ◽  
Vol 13 (23) ◽  
pp. 12089-12106 ◽  
Author(s):  
V. Amiridis ◽  
U. Wandinger ◽  
E. Marinou ◽  
E. Giannakaki ◽  
A. Tsekeri ◽  
...  
Keyword(s):  
Northern Africa ◽  
Saharan Dust ◽  
Individual Level ◽  
Dust Extinction ◽  
Absolute Bias ◽  
Moderate Resolution ◽  
Level 3 ◽  
Lidar Ratio ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer

Abstract. We demonstrate improvements in CALIPSO (Cloud–Aerosol Lidar and Infrared Pathfinder Satellite Observations) dust extinction retrievals over northern Africa and Europe when corrections are applied regarding the Saharan dust lidar ratio assumption, the separation of the dust portion in detected dust mixtures, and the averaging scheme introduced in the Level 3 CALIPSO product. First, a universal, spatially constant lidar ratio of 58 sr instead of 40 sr is applied to individual Level 2 dust-related backscatter products. The resulting aerosol optical depths show an improvement compared with synchronous and collocated AERONET (Aerosol Robotic Network) measurements. An absolute bias of the order of −0.03 has been found, improving on the statistically significant biases of the order of −0.10 reported in the literature for the original CALIPSO product. When compared with the MODIS (Moderate-Resolution Imaging Spectroradiometer) collocated aerosol optical depth (AOD) product, the CALIPSO negative bias is even less for the lidar ratio of 58 sr. After introducing the new lidar ratio for the domain studied, we examine potential improvements to the climatological CALIPSO Level 3 extinction product: (1) by introducing a new methodology for the calculation of pure dust extinction from dust mixtures and (2) by applying an averaging scheme that includes zero extinction values for the nondust aerosol types detected. The scheme is applied at a horizontal spatial resolution of 1° × 1° for ease of comparison with the instantaneous and collocated dust extinction profiles simulated by the BSC-DREAM8b dust model. Comparisons show that the extinction profiles retrieved with the proposed methodology reproduce the well-known model biases per subregion examined. The very good agreement of the proposed CALIPSO extinction product with respect to AERONET, MODIS and the BSC-DREAM8b dust model makes this dataset an ideal candidate for the provision of an accurate and robust multiyear dust climatology over northern Africa and Europe.

scholarly journals Ten Years of TRMM/VIRS On-Orbit Calibrations and Multiyear Comparisons of VIRS and MODIS

2008 ◽  
Vol 25 (12) ◽  
pp. 2259-2270 ◽  
Author(s):  
Cheng-Hsuan Lyu ◽  
William L. Barnes
Keyword(s):  
Tropical Rainfall Measuring Mission ◽  
Radiometric Calibration ◽  
Successful Operation ◽  
Earth Observing System ◽  
Spectral Bands ◽  
Calibration Algorithm ◽  
Moderate Resolution ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Terra Modis ◽  
Phase Angles

Abstract After 10 years of successful operation of the Tropical Rainfall Measuring Mission (TRMM)/Visible Infrared Scanner (VIRS), based on sensor performance, the authors have reexamined the calibration algorithms and identified several ways to improve the current VIRS level-1B radiometric calibration software. This study examines the trends in VIRS on-orbit calibration results by using lunar measurements to enable separation of the solar diffuser degradation from that of the VIRS Earth-viewing sensor and by comparing the radiometric data with two nearly identical Moderate Resolution Imaging Spectroradiometer (MODIS) instruments on board the NASA Earth Observing System (EOS) Terra and Aqua satellites. For the VIRS, with spectral bands quite similar to several of the MODIS bands, the integrated lunar reflectance data were measured, from January 1998 to March 2007, at phase angles ranging from 0.94° to 121.8°. The authors present trending of the lunar data over periods of 4 yr (Aqua/MODIS), 6 yr (Terra/MODIS), and 10 yr (TRMM/VIRS) and use these observations to examine instrument radiometric stability. The VIRS-measured lunar irradiances are compared with the MODIS-measured lunar irradiances at phase angles around 54°–56°. With the upcoming modified VIRS level-1B version 7 calibration algorithm, the VIRS, along with MODIS, should provide better references for intercalibrating multiple Earth-observing sensors.

scholarly journals Characteristics of Thermal Front in the Tropical Waters of Eastern Indian Ocean

2019 ◽  
Vol 21 (1) ◽  
pp. 25
Author(s):  
Soni Rohima Daulay ◽  
Tengku Ersti Yulika Sari ◽  
Usman Usman ◽  
Romie Jhonnerie
Keyword(s):  
Indian Ocean ◽  
Tropical Indian Ocean ◽  
Thermal Front ◽  
Image Edge Detection ◽  
Moderate Resolution ◽  
Level 3 ◽  
Resolution Imaging ◽  
Image Edge ◽  
Spatio Temporal ◽  
Moderate Resolution Imaging Spectroradiometer

This study aims to elucidate spatio-temporal variability of the thermal front in the eastern tropical Indian Ocean of the western Sumatera. The research was conducted during November 2017- February 2018. The Single Image Edge Detection (SIED) was applied to daily sea surface temperature (SST) data of 2016 of the level-3 Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) for the detection of thermal front. The number of the thermal front events during 2016 were 167 days. The distribution and frequency of thermal front mostly found in January, i.e. 23 days with SST mean of 30.3ºC. Whereas the lowest distribution appeared in November and the lowest frequency observed in September, i.e. 6 days with the SST mean of 29.1ºC. The highest temperature range of thermal front is between 31.4-32.0ºC and the lowest ranged between 26.4-29.3ºC. The occurrences of thermal front were commonly found in the open ocean. The highest frequency occurred in January and the lowest took place in September with the longest duration of 3 days.

scholarly journals Evaluation of Terra-MODIS C6 and C6.1 Aerosol Products against Beijing, XiangHe, and Xinglong AERONET Sites in China during 2004-2014

2019 ◽  
Vol 11 (5) ◽  
pp. 486 ◽  
Author(s):  
Muhammad Bilal ◽  
Majid Nazeer ◽  
Janet Nichol ◽  
Zhongfeng Qiu ◽  
Lunche Wang ◽  
...  
Keyword(s):  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Deep Blue ◽  
Moderate Resolution ◽  
Level 3 ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Terra Modis ◽  
Level 2 ◽  
Better Than

In this study, Terra-MODIS (Moderate Resolution Imaging Spectroradiometer) Collections 6 and 6.1 (C6 & C6.1) aerosol optical depth (AOD) retrievals with the recommended high-quality flag (QF = 3) were retrieved from Dark-Target (DT), Deep-Blue (DB) and merged DT and DB (DTB) level–2 AOD products for verification against Aerosol Robotic Network (AERONET) Version 3 Level 2.0 AOD data obtained from 2004–2014 for three sites located in the Beijing-Tianjin-Hebei (BTH) region. These are: Beijing, located over mixed bright urban surfaces, XiangHe located over suburban surfaces, and Xinglong located over hilly and vegetated surfaces. The AOD retrievals were also validated over different land-cover types defined by static monthly NDVI (Normalized Difference Vegetation Index) values obtained from the Terra-MODIS level-3 product (MOD13A3). These include non-vegetated surfaces (NVS, NDVI < 0.2), partially vegetated surfaces (PVS, 0.2 ≤ NDVI ≤ 0.3), moderately vegetated surfaces (MVS, 0.3 < NDVI < 0.5) and densely vegetated surfaces (DVS, NDVI ≥ 0.5). Results show that the DT, DB, and DTB-collocated retrievals achieve a high correlation coefficient of ~ 0.90–0.97, 0.89–0.95, and 0.86–0.95, respectively, with AERONET AOD. The DT C6 and C6.1 collocated retrievals were comparable at XiangHe and Xinglong, whereas at Beijing, the percentage of collocated retrievals within the expected error (↔EE) increased from 21.4% to 35.5%, the root mean square error (RMSE) decreased from 0.37 to 0.24, and the relative percent mean error (RPME) decreased from 49% to 27%. These results suggest significant relative improvement in the DT C6.1 product. The percentage of DB-collocated AOD retrievals ↔EE was greater than 70% at Beijing and Xinglong, whereas less than 66% was observed at XiangHe. Similar to DT AOD, DTB AOD retrievals performed well at XiangHe and Xinglong compared with Beijing. Regionally, DB C6 and C6.1-collocated retrievals performed better than DT and DTB in terms of good quality retrievals and relatively small errors. For diverse vegetated surfaces, DT-collocated retrievals reported small errors and good quality retrievals only for NVS and DVS, whereas larger errors were reported for PVS. MVS. DB contains good quality AOD retrievals over PVS, MVS, and DVS compared with NVS. DTB C6.1 collocated retrievals were better than C6 over NVS, PVS, and DVS. C6.1 is substantially improved overall, compared with C6 at local and regional scales, and over diverse vegetated surfaces.

scholarly journals Observed HIRS and MODIS High-Cloud Frequencies in the 2000s

2019 ◽  
Vol 58 (11) ◽  
pp. 2469-2478
Author(s):  
Richard A. Frey ◽  
W. Paul Menzel
Keyword(s):  
Cloud Detection ◽  
High Cloud ◽  
Clear Sky ◽  
Spectral Bands ◽  
Moderate Resolution ◽  
Summer Maximum ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Cloud Parameter ◽  
Cloud Top Pressure

AbstractThis paper compares the cloud parameter data records derived from High Resolution Infrared Radiation Sounder (HIRS) and Moderate Resolution Imaging Spectroradiometer (MODIS) measurements from the years 2003 through 2013. Cloud-top pressure (CTP) and effective emissivity (εf; cloud emissivity multiplied by cloud fraction) are derived using the 15-μm spectral bands in the CO2 absorption band and implementing the CO2-slicing technique; the approach is robust for high semitransparent clouds but weak for low clouds with little thermal contrast from clear-sky radiances. The high-cloud (HiCld; with CTP less than 440 hPa) seasonal cycles of HIRS and MODIS observations are found to be in sync, but the HIRS frequency of detection is about 10% higher than that of MODIS (which is attributed to a lower threshold for cloud detection in the HIRS CO2 bands). Differences are largest during nighttime and at the beginning of the time series (2003–06). Both show Northern Hemisphere (NH) and Southern Hemisphere (SH) seasonal HiClds are out of phase and both agree within 2% on NH–SH HiCld differences. During the summer, maximum HiCld frequency averages 5% more in the NH.

scholarly journals Evaluation of JAXA Himawari-8-AHI Level-3 Aerosol Products over Eastern China

Atmosphere ◽  
2019 ◽  
Vol 10 (4) ◽  
pp. 215 ◽  
Author(s):  
Ding Li ◽  
Kai Qin ◽  
Lixin Wu ◽  
Jian Xu ◽  
Husi Letu ◽  
...  
Keyword(s):  
Eastern China ◽  
Retrieval Algorithm ◽  
High Temporal Resolution ◽  
Aerosol Model ◽  
Significant Difference ◽  
Moderate Resolution ◽  
Level 3 ◽  
Resolution Imaging ◽  
Moderate Resolution Imaging Spectroradiometer ◽  
Land Surfaces

A novel geostationary satellite, the H8/AHI (Himawari-8/Advanced Himawari Imager), greatly improved the scan times per day covering East Asia, and the operational products have been stably provided for a period of time. Currently, atmospheric aerosol pollution is a major concern in China. H8/AHI aerosol products with a high temporal resolution are helpful for real-time monitoring of subtle aerosol variation. However, the H8/AHI aerosol optical thickness (AOT) product has been updated three times since its launch, and the evaluation of this dataset is currently rare. In order to validate its accuracy, this study compared the H8/AHI Level-3 (L3) hourly AOT products of all versions with measurements obtained from eleven sunphotometer sites located in eastern China from 2015 to 2018. Moderate Resolution Imaging Spectroradiometer (MODIS) Collection 6 AOT products from the same period were also used for inter-comparison. Although the H8/AHI AOT retrievals in version 010 show a moderate agreement with ground-based observations (correlation coefficient (R): 0.66–0.85), and the time series analysis shows that it can effectively monitor hourly variation, it suffers from an obvious underestimation of 0.3 compared to ground-based and MODIS observations. After the retrieval algorithm updated the predefined aerosol model, the overall underestimation of AHI AOTs was solved (version 010 slope: 0.43–0.62, version 030 slope: 0.75–1.02), and the AOTs in version 030 show a high agreement with observations from ten sites (R: 0.73–0.91). In addition, the surface reflectance dataset derived from the minimum reflectivity model in version 010 is inaccurate in parts of eastern China, for both “bright” and “dark” land surfaces, which leads to the overestimation of the AOT values under low aerosol loads at the Beijing and Xianghe sites. After the update of the surface dataset in version 030, this phenomenon was alleviated, resulting in no significant difference in scatterplots under different surface conditions. The AOTs of H8/AHI version 030 show a significant improvement compared to the previous two versions, but the spatial distribution of AHI is still different from MODIS AOT products due to the differences in sensors and algorithms. Therefore, although the evaluation in this study demonstrates the effectiveness of H8/AHI AOT products for aerosol monitoring at fine temporal resolutions, the performance of H8/AHI AOT products needs further study by considering more conditions.

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