scholarly journals Estudo das máximas e mínimas colunas totais de NO2 sobre a região nordeste do Brasil

2018 ◽  
Vol 40 ◽  
pp. 174
Author(s):  
Paulo Antunes Dias Pereira Calado ◽  
Glauber Lopes Mariano ◽  
Ericka Voss Chagas Mariano
Keyword(s):  
Anthropogenic Sources ◽  
Data Series ◽  
Ozone Monitoring Instrument ◽  
High Concentration ◽  
Northeast Region ◽  
A Value ◽  
Maximum Value ◽  
Erdas Imagine ◽  
Ozone Monitoring ◽  
The City

Nitrogen dioxide (NO2) is a gas emitted from anthropogenic sources directly into the atmosphere, with the most relevant being automotive vehicles. In this work were used the  softwares Erdas Imagine, GRADS and R with data obtained from the NASA Geovanni platform (available at http://giovanni.gsfc.nasa.gov/giovanni/) from the Ozone Monitoring Instrument (OMI) sensor located on the satellite AURA. In the data series, averages, minimum and maximum were used to observe and identify the areas with the highest concentration of NO2 in the Northeast region and the behavior of the pollutant on the same region. Among the maximum values identified in each of the months, nine occurred in Bahia including the maximum value of the whole series in July in the region near Roda Velha in Bahia and has a value of 4.88E+15 1/cm2, the state with the lowest occurrence of high concentration values is Rio Grande do Norte, but the lowest mean (2.06E+15 1/cm2) and the lowest value (1.75E+15 1/cm2) occur in the region near the city of São Luís (Maranhão) at 2.06E+15 1/cm2.

scholarly journals Intercomparison of stratospheric nitrogen dioxide columns retrieved from ground-based DOAS and FTIR and satellite DOAS instruments over the subtropical Izana station

2016 ◽  
Vol 9 (9) ◽  
pp. 4471-4485 ◽  
Author(s):  
Cristina Robles-Gonzalez ◽  
Mónica Navarro-Comas ◽  
Olga Puentedura ◽  
Matthias Schneider ◽  
Frank Hase ◽  
...  
Keyword(s):  
Relative Difference ◽  
Field Of View ◽  
Atmospheric Composition ◽  
Optical Absorption Spectroscopy ◽  
Data Series ◽  
Composition Change ◽  
Ozone Monitoring Instrument ◽  
Vertical Column ◽  
Ozone Monitoring ◽  
Scanning Imaging

Abstract. A 13-year analysis (2000–2012) of the NO2 vertical column densities derived from ground-based (GB) instruments and satellites has been carried out over the Izaña NDACC (Network for the Detection of the Atmospheric Composition Change) subtropical site. Ground-based DOAS (differential optical absorption spectroscopy) and FTIR (Fourier transform infrared spectroscopy) instruments are intercompared to test mutual consistency and then used for validation of stratospheric NO2 from OMI (Ozone Monitoring Instrument) and SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY). The intercomparison has been carried out taking into account the various differences existing in instruments, namely temporal coincidence, collocation, sensitivity, field of view, etc. The paper highlights the importance of considering an “effective solar zenith angle” instead of the actual one when comparing direct-sun instruments with zenith sky ones for a proper photochemical correction. Results show that NO2 vertical column densities mean relative difference between FTIR and DOAS instruments is 2.8 ± 10.7 % for a.m. data. Both instruments properly reproduce the NO2 seasonal and the interannual variation. Mean relative difference of the stratospheric NO2 derived from OMI and DOAS is −0.2 ± 8.7 % and from OMI and FTIR is −1.6 ± 6.7 %. SCIAMACHY mean relative difference is of 3.7 ± 11.7 and −5.7 ± 11.0 % for DOAS and FTIR, respectively. Note that the days used for the intercomparison are not the same for all the pairs of instruments since it depends on the availability of data. The discrepancies are found to be seasonally dependent with largest differences in winter and excellent agreement in the spring months (AMJ). A preliminary analysis of NO2 trends has been carried out with the available data series. Results show increases in stratospheric NO2 columns in all instruments but larger values in those that are GB than that expected by nitrous oxide oxidation. The possible reasons for the discrepancy between instruments and the positive trends are discussed in the text.

scholarly journals Updated SAO OMI formaldehyde retrieval

2014 ◽  
Vol 7 (1) ◽  
pp. 1-31 ◽  
Author(s):  
G. González Abad ◽  
X. Liu ◽  
K. Chance ◽  
H. Wang ◽  
T. P. Kurosu ◽  
...  
Keyword(s):  
Theoretical Basis ◽  
Retrieval Algorithm ◽  
Reference Spectrum ◽  
Ozone Monitoring Instrument ◽  
High Concentration ◽  
Air Mass ◽  
Mass Factor ◽  
Ozone Monitoring ◽  
Collisional Complex ◽  
Level 2

Abstract. We present and discuss the Smithsonian Astrophysical Observatory (SAO) formaldehyde (H2CO) retrieval algorithm for the Ozone Monitoring Instrument (OMI) which is the operational retrieval for NASA OMI H2CO. The version of the algorithm described here includes relevant changes with respect to the operational one, including differences in the reference spectra for H2CO, the fit of O2-O2 collisional complex, updates in the high resolution solar reference spectrum, the use of a model reference sector over the remote Pacific Ocean to normalize the retrievals, an updated Air Mass Factor (AMF) calculation scheme, and the inclusion of scattering weights and vertical H2CO profile in the level 2 products. The theoretical basis of the retrieval is discussed in detail. Typical values for retrieved vertical columns are between 4 × 1015 and 4 × 1016 molecules cm−2 with typical fitting uncertainties ranging between 40% and 100%. In high concentration regions the errors are usually reduced to 30%. The detection limit is estimated at 3 × 1015 molecules cm−2. These updated retrievals are compared with previous ones.

scholarly journals Comparison of aerosol optical depths from the Ozone Monitoring Instrument (OMI) on Aura with results from airborne sunphotometry, other space and ground measurements during MILAGRO/INTEX-B

2009 ◽  
Vol 9 (2) ◽  
pp. 9961-10013 ◽  
Author(s):  
J. M. Livingston ◽  
J. Redemann ◽  
P. B. Russell ◽  
O. Torres ◽  
B. Veihelmann ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Mexico City ◽  
Optical Depth ◽  
Biomass Burning ◽  
Ozone Monitoring Instrument ◽  
Aerosol Model ◽  
Monitoring Instrument ◽  
Biomass Burning Aerosol ◽  
Ozone Monitoring ◽  
The City

Abstract. Airborne sunphotometer measurements are used to evaluate retrievals of extinction aerosol optical depth (AOD) from spatially coincident and temporally near-coincident measurements by the Ozone Monitoring Instrument (OMI) aboard the Aura satellite during the March 2006 Megacity Initiative-Local And Global Research Observations/Phase B of the Intercontinental Chemical Transport Experiment (MILAGRO/INTEX-B). The 14-channel NASA Ames Airborne Tracking Sunphotometer (AATS) flew on nine missions over the Gulf of Mexico and four in or near the Mexico City area. Retrievals of AOD from near-coincident AATS and OMI measurements are compared for three flights over the Gulf of Mexico for flight segments when the aircraft flew at altitudes 60–70 m a.s.l., and for one flight over Mexico City when the aircraft flew ~420–590 m a.g.l. OMI-measured top of atmosphere (TOA) reflectances are routinely inverted to yield aerosol products such as AOD and aerosol absorption optical depth (AAOD) using two different retrieval algorithms: a near-UV (OMAERUV) and a multiwavelength (OMAERO) technique. This study uses the archived Collection 3 data products from both algorithms. In particular, AATS and OMI AOD comparisons are presented for AATS data acquired in 20 OMAERUV retrieval pixels (15 over water) and 19 OMAERO pixels (also 15 over water). At least four pixels for one of the over-water coincidences and all pixels for the over-land case were cloud-free. Coincident AOD retrievals from 17 pixels of the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard Aqua are available for two of the over-water flights and are shown to agree with AATS AODs to within root mean square (RMS) differences of 0.00–0.06, depending on wavelength. Near-coincident ground-based AOD measurements from ground-based sun/sky radiometers operated as part of the Aerosol Robotic Network (AERONET) at three sites in and near Mexico City are also shown and are generally consistent with the AATS AODs (which exclude any AOD below the aircraft) both in magnitude and spectral dependence. The OMAERUV algorithm retrieves AODs corresponding to a non-absorbing aerosol model for all three over-water comparisons, whereas the OMAERO algorithm retrieves best-fit AODs corresponding to an absorbing biomass-burning aerosol model for two of the three over-water cases. For the four cloud-free pixels in one over-water coincidence (10 March), the OMAERUV retrievals underestimate the AATS AODs by ~0.20, which exceeds the expected retrieval uncertainty, but retrieved AODs agree with AATS values within uncertainties for the other two over-water events. When OMAERO retrieves AODs corresponding to a biomass-burning aerosol over water, the values significantly overestimate the AATS AODs (by up to 0.55). For the Mexico City coincidence, comparisons are presented for a non-urban region ~50–70 km northeast of the city and for a site near the center of the city. OMAERUV retrievals are consistent with AERONET AOD magnitudes for the non-urban site, but are nearly double the AATS and AERONET AODs (with differences of up to 0.29) in the center of the city. Corresponding OMAERO retrievals exceed the AATS and/or AERONET AODs by factors of 3 to 10.

scholarly journals Updated Smithsonian Astrophysical Observatory Ozone Monitoring Instrument (SAO OMI) formaldehyde retrieval

2015 ◽  
Vol 8 (1) ◽  
pp. 19-32 ◽  
Author(s):  
G. González Abad ◽  
X. Liu ◽  
K. Chance ◽  
H. Wang ◽  
T. P. Kurosu ◽  
...  
Keyword(s):  
Temporal Stability ◽  
Cloud Fraction ◽  
Retrieval Algorithm ◽  
Reference Spectrum ◽  
Ozone Monitoring Instrument ◽  
High Concentration ◽  
Monitoring Instrument ◽  
Mass Factor ◽  
Ozone Monitoring ◽  
Level 2

Abstract. We present and discuss the Smithsonian Astrophysical Observatory (SAO) formaldehyde (H2CO) retrieval algorithm for the Ozone Monitoring Instrument (OMI) which is the operational retrieval for NASA OMI H2CO. The version of the algorithm described here includes relevant changes with respect to the operational one, including differences in the reference spectra for H2CO, the fit of O2–O2 collisional complex, updates in the high-resolution solar reference spectrum, the use of a model reference sector over the remote Pacific Ocean to normalize the retrievals, an updated air mass factor (AMF) calculation scheme, and the inclusion of scattering weights and vertical H2CO profile in the level 2 products. The setup of the retrieval is discussed in detail. We compare the results of the updated retrieval with the results from the previous SAO H2CO retrieval. The improvement in the slant column fit increases the temporal stability of the retrieval and slightly reduces the noise. The change in the AMF calculation has increased the AMFs by 20%, mainly due to the consideration of the radiative cloud fraction. Typical values for retrieved vertical columns are between 4 × 1015 and 4 × 1016 molecules cm−2, with typical fitting uncertainties ranging between 45 and 100%. In high-concentration regions the errors are usually reduced to 30%. The detection limit is estimated at 1 × 1016 molecules cm−2.

scholarly journals Comparison of aerosol optical depths from the Ozone Monitoring Instrument (OMI) on Aura with results from airborne sunphotometry, other space and ground measurements during MILAGRO/INTEX-B

2009 ◽  
Vol 9 (18) ◽  
pp. 6743-6765 ◽  
Author(s):  
J. M. Livingston ◽  
J. Redemann ◽  
P. B. Russell ◽  
O. Torres ◽  
B. Veihelmann ◽  
...  
Keyword(s):  
Gulf Of Mexico ◽  
Mexico City ◽  
Optical Depth ◽  
Biomass Burning ◽  
Ozone Monitoring Instrument ◽  
Aerosol Model ◽  
City Area ◽  
Biomass Burning Aerosol ◽  
Ozone Monitoring ◽  
The City

Abstract. Airborne sunphotometer measurements are used to evaluate retrievals of extinction aerosol optical depth (AOD) from spatially coincident and temporally near-coincident measurements by the Ozone Monitoring Instrument (OMI) aboard the Aura satellite during the March 2006 Megacity Initiative-Local And Global Research Observations/Phase B of the Intercontinental Chemical Transport Experiment (MILAGRO/INTEX-B). The 14-channel NASA Ames Airborne Tracking Sunphotometer (AATS) flew on nine missions over the Gulf of Mexico and four in or near the Mexico City area. Retrievals of AOD from near-coincident AATS and OMI measurements are compared for three flights over the Gulf of Mexico for flight segments when the aircraft flew at altitudes 60–70 m above sea level, and for one flight over the Mexico City area where the aircraft was restricted to altitudes ~320–800 m above ground level over the rural area and ~550–750 m over the city. OMI-measured top of atmosphere (TOA) reflectances are routinely inverted to yield aerosol products such as AOD and aerosol absorption optical depth (AAOD) using two different retrieval algorithms: a near-UV (OMAERUV) and a multiwavelength (OMAERO) technique. This study uses the archived Collection 3 data products from both algorithms. In particular, AATS and OMI AOD comparisons are presented for AATS data acquired in 20 OMAERUV retrieval pixels (15 over water) and 19 OMAERO pixels (also 15 over water). At least four pixels for one of the over-water coincidences and all pixels for the over-land case were cloud-free. Coincident AOD retrievals from 17 pixels of the Moderate Resolution Imaging Spectroradiometer (MODIS) aboard Aqua are available for two of the over-water flights and are shown to agree with AATS AODs to within root mean square (RMS) differences of 0.00–0.06, depending on wavelength. Near-coincident ground-based AOD measurements from ground-based sun/sky radiometers operated as part of the Aerosol Robotic Network (AERONET) at three sites in and near Mexico City are also shown and are generally consistent with the AATS AODs (which exclude any AOD below the aircraft) both in magnitude and spectral dependence. The OMAERUV algorithm retrieves AODs corresponding to a non-absorbing aerosol model for all three over-water comparisons whereas the OMAERO algorithm retrieves best-fit AODs corresponding to an absorbing biomass-burning aerosol model for two of the three over-water cases. For the four cloud-free pixels in one over-water coincidence (10 March), the OMAERUV retrievals underestimate the AATS AODs by ~0.20, which exceeds the expected retrieval uncertainty, but retrieved AODs agree with AATS values within uncertainties for the other two over-water events. When OMAERO retrieves AODs corresponding to a biomass-burning aerosol over water, the values significantly overestimate the AATS AODs (by up to 0.55). For the Mexico City coincidence, comparisons are presented for a non-urban region ~50–70 km northeast of the city and for a site near the center of the city. OMAERUV retrievals are consistent with AERONET AOD magnitudes for the non-urban site, but are nearly double the AATS and AERONET AODs (with differences of up to 0.29) in the center of the city. Corresponding OMAERO retrievals exceed the AATS and/or AERONET AODs by factors of 3 to 10.

scholarly journals Nitrogen dioxide stratospheric column at the subtropical NDACC station of Izaña from DOAS, FTIR and satellite instrumentation

2016 ◽  
Author(s):  
Cristina Robles-Gonzalez ◽  
Mónica Navarro-Comas ◽  
Olga Puentedura ◽  
Matthias Schneider ◽  
Frank Hase ◽  
...  
Keyword(s):  
Relative Difference ◽  
Field Of View ◽  
Atmospheric Composition ◽  
Optical Absorption Spectroscopy ◽  
Data Series ◽  
Composition Change ◽  
Ozone Monitoring Instrument ◽  
Vertical Column ◽  
Ozone Monitoring ◽  
Scanning Imaging

Abstract. A 13-years analysis (2000–2012) of the NO2 vertical column densities (VCD) derived from ground-based (GB) instruments and satellites has been carried out over the Izaña NDACC (Network for the Detection of the Atmospheric Composition Change) subtropical site. Ground-based DOAS (Differential Optical Absorption Spectroscopy) and FTIR (Fourier Transform InfraRed spectroscopy) instruments are intercompared to test mutual consistency and then use for validation of stratospheric NO2 from OMI (Ozone Monitoring Instrument) and SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY). The intercomparison has been carried out taking into account the various differences existing in instruments, namely temporal coincidence, collocation, sensitivity, field of view, etc. The paper highlights the importance of considering an "effective solar zenith angle" instead of the actual one when comparing direct sun instruments with zenith sky ones for a proper photochemical correction. Results show that NO2 vertical column densities mean relative difference between FTIR and DOAS instruments is 2.8 ± 10.7 % for AM data. Both instruments properly reproduce the NO2 seasonal and the interannual variation. Mean relative difference of the stratospheric NO2 derived from OMI and DOAS is −0.2 ± 8.7 % and from OMI and FTIR is −1.6 ± 6.7. SCIAMACHY mean relative difference is of 3.7 ± 11.7 % and −5.7 ± 11.0 % for DOAS and FTIR, respectively. Note that the days used for the intercomparison are not the same for all the pairs of instruments since it depends on the availability of data. The discrepancies are found to be seasonally dependent with largest differences in winter and excellent agreement in the spring months (AMJ). A preliminary analysis of NO2 trends has been carried out with the available data series. Results show positive values in all instruments but larger values on the ground-based than that expected by nitrous oxide oxidation. The possible reasons of the discrepancy between instruments and the positive trends are discussed in the text.

scholarly journals Estudo da erosão no Seridó paraibano como indicador do processo de desertificação: Juazeirinho, Paraíba (Study of erosion in Seridó paraibano as an indicator of desertification: Juazeirinho, Paraíba)

2019 ◽  
Vol 12 (3) ◽  
pp. 876
Author(s):  
Edinete Maria de Oliveira Maria De Oliveira ◽  
Vanice Selva
Keyword(s):  
Anthropogenic Activities ◽  
Environmental Conservation ◽  
Natural Process ◽  
Northeast Region ◽  
Erosion Risk ◽  
A Value ◽  
Severe Erosion ◽  
The City ◽  
Natural Media ◽  
Anthropic Action

O estudo da erosão em regiões semiáridas, principalmente quando o solo e a vegetação tornam-se vulneráveis por meio de atividades antrópicas, sem que haja conservação do ambiente explorado, indica que além do processo erosivo natural, o ambiente erodido pode sofrer um processo de desertificação. Diante desse contexto foi possível observar e analisar a erosão, a vulnerabilidade e os riscos na região do Seridó paraibano, especialmente no município de Juazeirinho, por apresentar uma fisiografia de Caatinga, solo arenoso e baixa pluviosidade, além de apresentar econômica e socialmente, explorações de minérios, sobretudo, da rocha caulim. As proposições metodológicas colocadas no trabalho, às coletas feitas in loco e a ferramenta do SIG contribuiu para apontar indicadores de riscos à erosão tanto do processo natural quanto o antropogênico. Os resultados apontaram uma vulnerabilidade natural média e alta para a região estudada, devido às instabilidades pluviométricas e a condições geomorfológicas da área. O processo erosivo pela ação antrópica mostrou um alto e severo risco à erosão, consequentemente deixando o ambiente propicio à desertificação em que se constatou um valor de 217.686,12km², (46,56%) da área do município, praticamente a metade do mesmo, gerando, portanto, uma preocupação grave pelo empobrecimento do solo e da cobertura vegetal nativa.    A B S T R A C TThe study of erosion in semiarid regions, especially when the soil and vegetation become vulnerable through anthropogenic activities without environmental conservation explored, indicates that besides the natural erosive process, the eroded environment can suffer a process of desertification. In this context it was possible to observe and analyses the erosion, the vulnerability and risks in the Northeast region of Brazil, especially in the municipality of Juazeirinho by presenting a physiography of Caatinga, sandy soil and low rainfall, as well as present economic and socially, holdings of ores, especially, caulim rock. The methodological propositions placed on the work, the collections made on the spot and the GIS tool contributed to point indicators of risks erosion of both the natural process as anthropogenic. The results showed a natural medium and high vulnerability to the region studied, due to rainfall and geomorphologic conditions instability of the area. The erosive process by anthropic action showed a high and severe erosion risk, consequently leaving the environment propitious to desertification in which if found in a value of 217,686.12 Km ², (46.56%) the area of the city, practically half of the same, generating thus a serious concern by the impoverishment of soil and vegetation cover.Keywords: Erosion, vulnerability, Risks, Process of desertification, Mapping.  

A Selection of Bandung City Travel Route Using The FLOYD-WARSHALL Algorithm

2020 ◽  
Vol 12 (7) ◽  
Author(s):  
Muhammad Ghifari Arfananda ◽  
◽  
Surya Michrandi Nasution ◽  
Casi Setianingsih ◽  
◽  
...  
Keyword(s):  
Traffic Congestion ◽  
Rapid Development ◽  
Route Selection ◽  
Tourist Attractions ◽  
Tourist Destinations ◽  
A Value ◽  
Distance Data ◽  
Simple Additive Weighting ◽  
The City ◽  
Selection Of

The rapid development of information and technology, the city of Bandung tourism has also increased. However, tourists who visit the city of Bandung have problems with a limited time when visiting Bandung tourist attractions. Traffic congestion, distance, and the number of tourist destinations are the problems for tourists travel. The optimal route selection is the solution for those problems. Congestion and distance data are processed using the Simple Additive Weighting (SAW) method. Route selection uses the Floyd-Warshall Algorithm. In this study, the selection of the best route gets the smallest weight with a value of 5.127 from the Algorithm process. Based on testing, from two to five tourist attractions get an average calculation time of 3 to 5 seconds. This application is expected to provide optimal solutions for tourists in the selection of tourist travel routes.

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