| Home | [1–10] << 11 12 13 14 15 16 17 18 19 20 >> [21–30] |
|
| Records | |||||
|---|---|---|---|---|---|
| Author | Doumbia, E.H.T.; Liousse, C.; Keita, S.; Granier, L.; Granier, C.; Elvidge, C.D.; Elguindi, N.; Law, K. | ||||
| Title | Flaring emissions in Africa: Distribution, evolution and comparison with current inventories | Type | Journal Article | ||
| Year | 2019 | Publication  |
Atmospheric Environment | Abbreviated Journal | Atmospheric Environment |
| Volume | 199 | Issue | Pages | 423-434 | |
| Keywords | Remote Sensing | ||||
| Abstract | Flaring emissions are a major concern due to large uncertainties in the amount of chemical compounds released into the atmosphere and their evolution with time. A methodology based on DMSP (Defense Meteorological Satellite Program) nighttime light data combined with regional gas flaring volumes from National Oceanic and Atmospheric Administration's National Centers for Environmental Information (NOAA-NCEI) has been developed to estimate flaring emissions. This method is validated in Nigeria where individual field company data are available. The spatial distribution of CO2, CH4, NMVOCs, CO, OC, BC, SO2 and NOx is derived for the African continent for the period 1995–2010. A range of the emissions due to flaring is estimated based on the range of emission factors (EFs) for each chemical species. An average decrease in CO2 emissions of about 30% is found over Africa from 1995 to 2010, with Nigeria being the largest contributor to this reduction (up to 50%). Changes in the spatial distribution with time indicate local increases, particularly at offshore platforms, which are attributed to a lack of regulations as well as aging infrastructures in oil and gas fields. Comparisons with current inventories reveal differences in the location and magnitude of point source emissions. For chemical compounds such as NMVOCs and CH4, the ECLIPSE and EDGAR country-level values are considerably higher than the highest flaring emission estimated in this study for 2005. For species such as CO, OC, BC, SO2 and NOx, the emissions provided by the ECLIPSE and EDGAR inventories are generally within the same order of magnitude as the average values found in this study, with the exception of OC, BC and SO2 in which EDGAR provides much lower emissions. These discrepancies are likely due to either differences in the methodologies used to estimate the emissions, in the values of the emission factors considered, or in the definition of flaring sector. Our current estimations suggest that BC, CH4 and CO2 flaring emissions in Africa account for 1–15% (on average 7%), 0.5–8% (on average 2%) and 8–13% (on average 11%) of African total anthropogenic emissions, respectively. The contribution of flaring to African anthropogenic emissions varies widely among countries. For example, in Nigeria the average emissions due to flaring are estimated to be as high as 18% for BC, 10% for CH4 and 50% for CO2, which is significantly greater than the continental average and highlights the importance of emissions in flaring areas. |
||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | Editor | |||
| Language | Summary Language | Original Title | |||
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1352-2310 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | GFZ @ kyba @ | Serial | 2176 | ||
| Permanent link to this record | |||||
| Author | Johnson, R.S.; Zhang, J.; Hyer, E.J.; Miller, S.D.; Reid, J.S. | ||||
| Title | Preliminary investigations toward nighttime aerosol optical depth retrievals from the VIIRS Day/Night Band | Type | Journal Article | ||
| Year | 2013 | Publication |
Atmospheric Measurement Techniques | Abbreviated Journal | Atmos. Meas. Tech. |
| Volume | 6 | Issue | 5 | Pages | 1245-1255 |
| Keywords | VIIRS; remote sensing; Suomi NPP; aerosol; optical depth; AERONET; light pollution; measurements | ||||
| Abstract | A great need exists for reliable nighttime aerosol products at high spatial and temporal resolution. In this concept demonstration study, using Visible/Infrared Imager/Radiometer Suite (VIIRS) Day/Night Band (DNB) observations on the Suomi National Polar-orbiting Partnership (NPP) satellite, a new method is proposed for retrieving nighttime aerosol optical depth (τ) using the contrast between regions with and without artificial surface lights. Evaluation of the retrieved τ values against daytime AERONET data from before and after the overpass of the VIIRS satellite over the Cape Verde, Grand Forks, and Alta Floresta AERONET stations yields a coefficient of determination (r2) of 0.71. This study suggests that the VIIRS DNB has the potential to provide useful nighttime aerosol detection and property retrievals. | ||||
| Address | Department of Atmospheric Sciences, University of North Dakota, Grand Forks, ND, USA | ||||
| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | Editor | |||
| Language | Summary Language | Original Title | |||
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1867-8548 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | IDA @ john @ | Serial | 200 | ||
| Permanent link to this record | |||||
| Author | Zhang, J.; Jaker, S.L.; Reid, J.S.; Miller, S.D.; Solbrig, J.; Toth, T.D. | ||||
| Title | Characterization and application of artificial light sources for nighttime aerosol optical depth retrievals using the Visible Infrared Imager Radiometer Suite Day/Night Band | Type | Journal Article | ||
| Year | 2019 | Publication |
Atmospheric Measurement Techniques | Abbreviated Journal | Atmos. Meas. Tech. |
| Volume | 12 | Issue | 6 | Pages | 3209-3222 |
| Keywords | Remote Sensing | ||||
| Abstract | Using nighttime observations from Visible Infrared Imager Radiometer Suite (VIIRS) Day/Night band (DNB), the characteristics of artificial light sources are evaluated as functions of observation conditions, and incremental improvements are documented on nighttime aerosol retrievals using VIIRS DNB data on a regional scale. We find that the standard deviation of instantaneous radiance for a given artificial light source is strongly dependent upon the satellite viewing angle but is weakly dependent on lunar fraction and lunar angle. Retrieval of nighttime aerosol optical thickness (AOT) based on the novel use of these artificial light sources is demonstrated for three selected regions (United States, Middle East and India) during 2015. Reasonable agreement is found between nighttime AOTs from the VIIRS DNB and temporally adjacent daytime AOTs from the AErosol RObotic NETwork (AERONET) as well as from coincident nighttime AOT retrievals from the Cloud-Aerosol Lidar with Orthogonal Polarization (CALIOP), indicating the potential of this method to begin filling critical gaps in diurnal AOT information at both regional and global scales. Issues related to cloud, snow and ice contamination during the winter season, as well as data loss due to the misclassification of thick aerosol plumes as clouds, must be addressed to make the algorithm operationally robust. | ||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | Editor | |||
| Language | Summary Language | Original Title | |||
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1867-8548 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | GFZ @ kyba @ | Serial | 2583 | ||
| Permanent link to this record | |||||
| Author | Solbrig, J.E.; Miller, S.D.; Zhang, J.; Grasso, L.; Kliewer, A. | ||||
| Title | Assessing the stability of surface lights for use in retrievals of nocturnal atmospheric parameters | Type | Journal Article | ||
| Year | 2020 | Publication |
Atmospheric Measurement Techniques | Abbreviated Journal | Atmos. Meas. Tech. |
| Volume | 13 | Issue | 1 | Pages | 165-190 |
| Keywords | Remote Sensing | ||||
| Abstract | The detection and characterization of aerosols are inherently limited at night because the important information provided by visible spectrum observations is not available and infrared bands have limited sensitivity to aerosols. The VIIRS Day–Night Band (DNB) onboard the Suomi-NPP satellite is a first-of-its-kind calibrated sensor capable of collecting visible and near-infrared observations during both day and night. Multiple studies have suggested that anthropogenic light emissions such as those from cities and gas flares may be useable as light sources for the retrieval of atmospheric properties, including cloud and aerosol optical depth. However, their use in this capacity requires proper characterization of their intrinsic variation, which represents a source of retrieval uncertainty. In this study we use 18 months of cloud-cleared VIIRS data collected over five selected geographic domains to assess the stability of anthropogenic light emissions and their response to varied satellite and lunar geometries. Time series are developed for each location in each domain for DNB radiance, four infrared channels, and satellite and lunar geometric variables, and spatially resolved correlation coefficients are computed between DNB radiance and each of the other variables. This analysis finds that while many emissive light sources are too unstable to be used reliably for atmospheric retrievals, some sources exhibit a sufficient stability (relative standard deviation <20 %). Additionally, we find that while the radiance variability of surrounding surfaces (i.e., unpopulated land and ocean) is largely dependent on lunar geometry, the anthropogenic light sources are more strongly correlated with satellite viewing geometry. Understanding the spatially resolved relationships between DNB radiance and other parameters is a necessary first step towards characterizing anthropogenic light emissions and establishes a framework for a model to describe variability in a more general sense. | ||||
| Address | |||||
| Corporate Author | Thesis | ||||
| Publisher | Place of Publication | Editor | |||
| Language | Summary Language | Original Title | |||
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1867-8548 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | GFZ @ kyba @ | Serial | 3005 | ||
| Permanent link to this record | |||||
| Author | McHardy, T.M.; Zhang, J.; Reid, J.S.; Miller, S.D.; Hyer, E.J.; Kuehn, R.E. | ||||
| Title | An improved method for retrieving nighttime aerosol optical thickness from the VIIRS Day/Night Band | Type | Journal Article | ||
| Year | 2015 | Publication |
Atmospheric Measurement Techniques Discussions | Abbreviated Journal | Atmos. Meas. Tech. Discuss. |
| Volume | 8 | Issue | 5 | Pages | 5147-5178 |
| Keywords | Remote Sensing; Suomi NPP; VIIRS; DNB; VIIRS DNB; aerosol optical thickness; AERONET; lidar; SEAC4RS | ||||
| Abstract | Using Visible/Infrared Imaging Radiometer Suite (VIIRS) Day/Night Band (DNB) data, a method, dubbed the “variance method”, is developed for retrieving nighttime aerosol optical thickness (τ) values through the examination of the dispersion of radiance values above an artificial light source. Based on the improvement of a previous algorithm, this updated method derives a semi-quantitative indicator of nighttime τ using artificial light sources. Nighttime τ retrievals from the newly developed method are inter-compared with an interpolated value from late afternoon and early morning ground observations from four AErosol RObotic NETwork (AERONET) sites as well as column-integrated τ from one High Spectral Resolution Lidar (HSRL) site at Huntsville, AL during the NASA Studies of Emissions and Atmospheric Composition, Clouds and Climate Coupling by Regional Surveys (SEAC4RS) campaign, providing full diel coverage. Sensitivity studies are performed to examine the effects of lunar illumination on VIIRS τ retrievals made via the variance method, revealing that lunar contamination may have a smaller impact than previously thought, however the small sample size of this study limits the conclusiveness thus far. VIIRS τ retrievals yield a coefficient of determination (r2) of 0.60 and a root-mean-squared-error (RMSE) of 0.18 when compared against straddling daytime-averaged AERONET τ values. Preliminary results suggest that artificial light sources can be used for estimating regional and global nighttime aerosol distributions in the future. | ||||
| Address | Department of Atmospheric Sciences, University of North Dakota, Grand Forks, ND, USA | ||||
| Corporate Author | Thesis | ||||
| Publisher | European Geosciences Union | Place of Publication | Editor | ||
| Language | English | Summary Language | English | Original Title | |
| Series Editor | Series Title | Abbreviated Series Title | |||
| Series Volume | Series Issue | Edition | |||
| ISSN | 1867-8610 | ISBN | Medium | ||
| Area | Expedition | Conference | |||
| Notes | Approved | no | |||
| Call Number | IDA @ john @ | Serial | 1182 | ||
| Permanent link to this record | |||||