scholarly journals Full-azimuthal imaging-DOAS observations of NO<sub>2</sub> and O<sub>4</sub> during CINDI-2

2019 ◽  
Vol 12 (8) ◽  
pp. 4171-4190 ◽  
Author(s):  
Enno Peters ◽  
Mareike Ostendorf ◽  
Tim Bösch ◽  
André Seyler ◽  
Anja Schönhardt ◽  
...  
Keyword(s):  
Trace Gas ◽  
Optical Absorption Spectroscopy ◽  
Measuring Instruments ◽  
Azimuthal Distribution ◽  
Future Studies ◽  
Measurement Site ◽  
Atmospheric Observations ◽  
Relative Differences ◽  
Instrument Impact

Abstract. A novel imaging-DOAS (differential optical absorption spectroscopy) instrument IMPACT (Imaging MaPper for AtmospheriC observaTions) is presented combining full-azimuthal pointing (360∘) with a large vertical coverage (∼41∘). Complete panoramic scans are acquired at a temporal resolution of ∼15 min, enabling the retrieval of NO2 vertical profiles over the entire panorama around the measurement site. IMPACT showed excellent agreement (correlation >99 %) with coincident multiaxis DOAS (MAX-DOAS) measurements during the Second Cabauw Intercomparison of Nitrogen Dioxide measuring Instruments (CINDI-2) campaign. The temporal variability of NO2 slant columns within a typical MAX-DOAS vertical scanning sequence could be resolved and was as large as 20 % in a case study under good viewing conditions. The variation of corresponding profiles and surface concentrations was even larger (40 %). This variability is missed when retrieving trace gas profiles based on standard MAX-DOAS measurements. The azimuthal distribution of NO2 around the measurement site showed inhomogeneities (relative differences) up to 120 % (on average 35 %) on short timescales (individual panoramic scans). This is more than expected for the semirural location. We explain this behavior by the transport of pollution. Exploiting the instrument's advantages, the plume's trajectory during a prominent transport event could be reconstructed. Finally, the potential for retrieving information about the aerosol phase function from O4 slant columns along multiple almucantar scans of IMPACT is demonstrated, with promising results for future studies.

scholarly journals Full-azimuthal imaging-DOAS observations of NO<sub>2</sub> and O<sub>4</sub> during CINDI-2

2019 ◽  
Author(s):  
Enno Peters ◽  
Mareike Ostendorf ◽  
Tim Bösch ◽  
André Seyler ◽  
Anja Schönhardt ◽  
...  
Keyword(s):  
Temporal Variability ◽  
Trace Gas ◽  
Vertical Profiles ◽  
Azimuthal Distribution ◽  
Future Studies ◽  
Measurement Site ◽  
Short Time ◽  
Relative Differences ◽  
Instrument Impact

Abstract. A novel imaging-DOAS instrument (IMPACT) is presented combining full-azimuthal pointing (360°) with a large vertical coverage (~ 40°). Complete panoramic scans are acquired at a temporal resolution of ~ 15 minutes enabling the retrieval of NO2 vertical profiles over the entire panorama around the measurement site. IMPACT showed excellent agreement (correlation > 99 %) with coinciding MAX-DOAS measurements during the CINDI-2 campaign. The temporal variability of NO2 slant columns within a typical MAX-DOAS vertical scanning sequence could be resolved and was as large as 20 % in a case study under good viewing conditions. The variation of corresponding profiles and surface concentrations were even larger (40 %). This variability is missed when retrieving trace gas profiles based on standard MAX-DOAS measurements. The azimuthal distribution of NO2 around the measurement site showed inhomogeneities (relative differences) up to 120 % (on average 35 %) on short time scales (individual panoramic scans). This is more than expected taking into account the semi-rural location. One reason for this are transport events. Exploiting the instrument's advantages, the plume's trajectory during a prominent transport event could be reconstructed. Furthermore, the potential of retrieving information about the aerosol phase function from O4 slant columns along multiple almucantar scans of IMPACT is demonstrated, with promising results for future studies.

scholarly journals Intercomparison of MAX-DOAS vertical profile retrieval algorithms: studies on field data from the CINDI-2 campaign

2020 ◽  
Author(s):  
Jan-Lukas Tirpitz ◽  
Udo Frieß ◽  
François Hendrick ◽  
Carlos Alberti ◽  
Marc Allaart ◽  
...  
Keyword(s):  
Lower Troposphere ◽  
Trace Gas ◽  
Optical Absorption Spectroscopy ◽  
Measuring Instruments ◽  
Visible Radiation ◽  
Radiation Spectra ◽  
Tropospheric Aerosol ◽  
Wide Range ◽  
Sun Photometer ◽  
Low Sensitivity

Abstract. Multi-AXis Differential Optical Absorption Spectroscopy (MAX-DOAS) is a well-established ground-based measurement technique for the detection of aerosols and trace gases particularly in the boundary layer and the lower troposphere: ultraviolet- and visible radiation spectra of skylight are analysed to obtain information on different atmospheric parameters, integrated over the light path from space to the instrument. An appropriate set of spectra recorded under different viewing geometries ("Multi-Axis") allows retrieval of tropospheric aerosol and trace gas vertical distributions by applying numerical inversion methods. The second Cabauw Intercomparison of Nitrogen Dioxide measuring Instruments (CINDI-2) took place in Cabauw (The Netherlands) in September 2016 with the aim of assessing the consistency of MAX-DOAS measurements of tropospheric species (NO2, HCHO, O3, HONO, CHOCHO and O4). This was achieved through the coordinated operation of 36 spectrometers operated by 24 groups from all over the world, together with a wide range of supporting reference observations (in situ analysers, balloon sondes, lidars, Long-Path DOAS, sun photometer and others). In the presented study, the retrieved CINDI-2 MAX-DOAS trace gas (NO2, HCHO) and aerosol vertical profiles of 15 participating groups using different inversion algorithms are compared and validated against the colocated supporting observations. The profiles were found to be in good qualitative agreement: most participants obtained the same features in the retrieved vertical trace gas and aerosol distributions, however sometimes at different altitudes and of different intensity. Under clear sky conditions, the root-mean-square differences of aerosol optical thicknesses, trace gas (NO2, HCHO) vertical columns and surface concentrations among the results of individual participants vary between 0.01–0.1, (1.5–15) x 1014 molec cm-2 and (0.3–8) x 1010 molec cm-3, respectively. For the comparison against supporting observations, these values increase to 0.02–0.2, (11–55) x 1014 molec cm-2 and (0.8–9) x 1010 molec cm-3. It is likely that a large part of this increase is caused by imperfect spatio-temporal overlap of the different observations. In contrast to what is often assumed, the MAX-DOAS vertically integrated extinction profiles and the sun photometer total aerosol optical thickness were found to not necessarily being comparable quantities, unless information on the real aerosol vertical distribution is available to account for the low sensitivity of MAX-DOAS observations at higher altitudes.

scholarly journals ArcGIS Urban: an application for plan assessment

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Ellen Soward ◽  
Jianling Li
Keyword(s):  
United States ◽  
The United States ◽  
Spatial Context ◽  
Future Studies ◽  
Planning Profession ◽  
Gis Tools ◽  
Comprehensive Plans ◽  
Near Future ◽  
The City

AbstractMost cities in the United States rely on zoning to address important planning-related issues within their jurisdictions. Planners often use GIS tools to analyze these issues in a spatial context. ESRI’s ArcGIS Urban software seeks to provide the planning profession with a GIS-based solution for various challenges, including zoning’s impacts on the built environment and housing capacity.This research explores the use of ArcGIS Urban for assessing the existing zoning and comprehensive plans in meeting the projected residential growth in the near future using the City of Arlington, Texas as a case study. The exploration provides examples and lessons for how ArcGIS Urban might be used by planners to accomplish their tasks and highlights the capabilities and limitations of ArcGIS Urban in its current stand. The paper is concluded with some suggestions for future studies.

scholarly journals The Potential of GRASP/GARRLiC Retrievals for Dust Aerosol Model Evaluation: Case Study during the PreTECT Campaign

2021 ◽  
Vol 13 (5) ◽  
pp. 873
Author(s):  
Dimitra Konsta ◽  
Alexandra Tsekeri ◽  
Stavros Solomos ◽  
Nikolaos Siomos ◽  
Anna Gialitaki ◽  
...  
Keyword(s):  
Model Evaluation ◽  
Dust Concentration ◽  
Saharan Dust ◽  
North Coast ◽  
Concentration Profiles ◽  
Future Studies ◽  
Aerosol Model ◽  
The North ◽  
Sun Photometer

We use the Generalized Retrieval of Aerosol Surface Properties algorithm (GRASP) to compare with dust concentration profiles derived from the NMME-DREAM model for a specific dust episode. The GRASP algorithm provides the possibility of deriving columnar and vertically-resolved aerosol properties from a combination of lidar and sun-photometer observations. Herein, we apply GRASP for analysis of a Saharan dust outburst observed during the “PREparatory: does dust TriboElectrification affect our ClimaTe” campaign (PreTECT) that took place at the North coast of Crete, at the Finokalia ACTRIS station. GRASP provides column-averaged and vertically resolved microphysical and optical properties of the particles. The retrieved dust concentration profiles are compared with modeled concentration profiles derived from the NMME-DREAM dust model. To strengthen the results, we use dust concentration profiles from the POlarization-LIdar PHOtometer Networking method (POLIPHON). A strong underestimation of the maximum dust concentration is observed from the NMME-DREAM model. The reported differences between the retrievals and the model indicate a high potential of the GRASP algorithm for future studies of dust model evaluation.

scholarly journals Satellite monitoring of different vegetation types by differential optical absorption spectroscopy (DOAS) in the red spectral range

2007 ◽  
Vol 7 (1) ◽  
pp. 69-79 ◽  
Author(s):  
T. Wagner ◽  
S. Beirle ◽  
T. Deutschmann ◽  
M. Grzegorski ◽  
U. Platt
Keyword(s):  
Optical Absorption ◽  
Absorption Spectroscopy ◽  
Spectral Range ◽  
Near Infrared ◽  
Vegetation Type ◽  
Differential Optical Absorption Spectroscopy ◽  
Trace Gas ◽  
Satellite Monitoring ◽  
Optical Absorption Spectroscopy ◽  
Vegetation Types

Abstract. A new method for the satellite remote sensing of different types of vegetation and ocean colour is presented. In contrast to existing algorithms relying on the strong change of the reflectivity in the red and near infrared spectral region, our method analyses weak narrow-band (few nm) reflectance structures (i.e. "fingerprint" structures) of vegetation in the red spectral range. It is based on differential optical absorption spectroscopy (DOAS), which is usually applied for the analysis of atmospheric trace gas absorptions. Since the spectra of atmospheric absorption and vegetation reflectance are simultaneously included in the analysis, the effects of atmospheric absorptions are automatically corrected (in contrast to other algorithms). The inclusion of the vegetation spectra also significantly improves the results of the trace gas retrieval. The global maps of the results illustrate the seasonal cycles of different vegetation types. In addition to the vegetation distribution on land, they also show patterns of biological activity in the oceans. Our results indicate that improved sets of vegetation spectra might lead to more accurate and more specific identification of vegetation type in the future.

USING IDIOBLASTS TO GROUP LAURINOXYLON SPECIES: CASE STUDY FROM THE OLIGO-MIOCENE OF EUROPE

IAWA Journal ◽  
2016 ◽  
Vol 37 (3) ◽  
pp. 459-488 ◽  
Author(s):  
Dimitra Mantzouka ◽  
Vasileios Karakitsios ◽  
Jakub Sakala ◽  
Elisabeth A. Wheeler
Keyword(s):  
Fossil Wood ◽  
New Combination ◽  
The Czech Republic ◽  
Axial Parenchyma ◽  
Future Studies ◽  
Ray Parenchyma Cells ◽  
Type 3 ◽  
Of Greece

Several specimens of Lauraceae fossil wood from the Cenozoic of Greece (southern part of Lesbos), the Czech Republic (Kadaň-Zadní Vrch Hill and Jáchymov), and Hungary (Ipolytarnóc) were studied. When considering whether they belonged to the speciose fossil wood genus Laurinoxylon, we reviewed the literature and data from InsideWood on fossil and modern woods. As a result, we propose criteria for excluding a fossil Lauraceae wood from Laurinoxylon and list the species that should be excluded from this genus. The criteria (filters) proposed to exclude a genus from having relationships with Laurinoxylon are: A. Axial parenchyma features: A1. Marginal axial parenchyma, A2. Aliform to aliform-confluent paratracheal parenchyma. B. Ray features: B1. Rays higher than 1 mm, B2. Exclusively homocellular rays, B3. Rays more than 5 cells wide, B4. Rays storied. C. Porosity features: Ring-porous. D. Idioblasts: Absence of idioblasts. Based on the distribution of idioblasts, we recognize four groups in Laurinoxylon (Type 1 - with idioblasts associated only with ray parenchyma cells, Type 2a - with idioblasts associated with both ray and axial parenchyma, Type 2b - with idioblasts associated both with rays and present among the fibres, and Type 3 - with idioblasts associated with ray and axial parenchyma and also among the fibres) and list the extant genera with features of those groups. Such grouping helps with interpreting the relationships of fossil lauraceous woods with extant genera. We discuss the Oligocene–Miocene European species that belong to these Laurinoxylon groups, noting that some warrant reassignment to different genera or even families. Future studies are needed to determine whether new genera should be established to accommodate these species. We propose the new combination Cinnamomoxylon variabile (Privé-Gill & Pelletier) Mantzouka, Karakitsios, Sakala & Wheeler.

scholarly journals Chemical Incident Analysis Involving Storage of Fertilizer Product

2021 ◽  
Vol 38 (1) ◽  
Author(s):  
Rogerio De Medeiros Tocantins ◽  
Bettina Tomio Heckert ◽  
Rafael Salum de Oliveira ◽  
Hélio João Coelho ◽  
Gisele Chibinski Parabocz ◽  
...  
Keyword(s):  
Chemical Reaction ◽  
Water Bodies ◽  
Reaction Products ◽  
Future Studies ◽  
Adjacent Water ◽  
Forensic Engineering ◽  
Fertilizer Material ◽  
The City ◽  
Incident Analysis

A forensic engineering analyses of a chemical incident is presented that was classified as a self-sustaining decomposition (SSD) event, which occurred in a load of 10,000 tons of NK 21-00-21 fertilizer bulk stored inside a warehouse in the city of São Francisco do Sul in Brazil. The chemical reaction developed within the fertilizer mass and took several days to be controlled, resulting in the evacuation of thousands of residents. The water used to fight against the reaction, after having contact with the load of fertilizer material, promoted changes in adjacent water bodies, causing the death of animals (fish, crustaceans, and amphibians). The smoke from the chemical reaction products damaged the incident’s surrounding vegetation. Large SSD events are rare, with an average worldwide frequency of one every three years. Therefore, in addition to presenting a case study of this type of phenomenon, the main objective of this work is to discuss the causes that led to SSD reaction at this event, evaluate its consequences, and motivate future studies.

scholarly journals Intercomparison of four different in-situ techniques for ambient formaldehyde measurements in urban air

2005 ◽  
Vol 5 (3) ◽  
pp. 2897-2945 ◽  
Author(s):  
C. Hak ◽  
I. Pundt ◽  
C. Kern ◽  
U. Platt ◽  
J. Dommen ◽  
...  
Keyword(s):  
Regression Line ◽  
Ambient Air ◽  
Urban Site ◽  
Optical Absorption Spectroscopy ◽  
Measuring Instruments ◽  
Chromatographic Technique ◽  
In Situ Techniques ◽  
Time Period ◽  
The Individual

Abstract. Results from an intercomparison of several currently used in-situ techniques for the measurement of atmospheric formaldehyde (CH2O) are presented. The measurements were carried out at Bresso, an urban site in the periphery of Milan (Italy) as part of the FORMAT-I field campaign. Eight instruments were employed by six independent research groups using four different techniques: Differential Optical Absorption Spectroscopy (DOAS), Fourier Transform Infra Red (FTIR) interferometry, the fluorimetric Hantzsch reaction technique (five instruments) and a chromatographic technique employing C18-DNPH-cartridges (2,4-dinitrophenylhydrazine). White type multi-reflection systems were employed for the optical techniques in order to avoid spatial CH2O gradients and ensure the sampling of nearly the same air mass by all instruments. Between 23 and 31 July 2002, up to 13 ppbv of CH2O were observed. The concentrations lay well above the detection limits of all instruments. The formaldehyde concentrations determined with DOAS, FTIR and the Hantzsch instruments were found to agree within ±11%, with the exception of one Hantzsch instrument, which gave systematically higher values. The two hour integrated samples by DNPH yielded up to 25% lower concentrations than the data of the continuously measuring instruments averaged over the same time period. The consistency between the DOAS and the Hantzsch method was better than during previous intercomparisons in ambient air with slopes of the regression line not significantly differing from one. The differences between the individual Hantzsch instruments could be attributed in part to the calibration standards used. Possible systematic errors of the methods are discussed.

scholarly journals A Case Study of Chinese Students’ and IEP Faculty Perceptions of a Creativity and Critical Thinking Course

2019 ◽  
Vol 9 (3) ◽  
pp. 34 ◽  
Author(s):  
James Badger
Keyword(s):  
Critical Thinking ◽  
International Students ◽  
Faculty Perceptions ◽  
Chinese Students ◽  
Intensive English ◽  
Future Studies ◽  
Effective Strategies ◽  
Intensive English Programs ◽  
Analytic Skills

The attention to fostering learners&rsquo; critical thinking and creativity skills in secondary school and college students is growing in Western and non-Western countries. This study investigated the integration of a creativity and critical thinking course in an Intensive English Programs (IEP) to determine how the same course may contribute to international students&rsquo; linguistic skills and analytic abilities in preparation for college. Perry&rsquo;s (1970) conceptual framework was adopted to analyze Chinese students&rsquo; views of problems presented in a creativity and critical thinking course, and how the same knowledge related to the Chinese students&rsquo; prior educational experiences as well as connect to their future studies. IEP faculty and administrator&rsquo;s perceptions provided an additional perspective into the purpose and learning outcomes of the same course. Findings from this research address a gap in the literature that seeks effective strategies and models for IEPs to foster international students&rsquo; analytic skills in preparation for college studies.

scholarly journals Developing and evaluating national severity distributions for use in Burden of Disease studies: a case study of cancers in Scotland

2019 ◽  
Vol 4 (3) ◽  
Author(s):  
Grant Wyper ◽  
Ian Grant ◽  
Eilidh Fletcher ◽  
Gerry McCartney ◽  
Diane Stockton
Keyword(s):  
Burden Of Disease ◽  
Weighted Average ◽  
Systematic Bias ◽  
Specific Data ◽  
Tract Cancer ◽  
Disability Weights ◽  
Cancer Types ◽  
Relative Differences ◽  
The Impact

BackgroundIncreasingly Burden of Disease (BOD) measures are being used to influence policy decisions because they summarise health loss in an equitable manner. An important part of producing non-fatal BOD estimates are severity distributions (SDs). The Global Burden of Disease (GBD) study use the same SDs across countries due to a lack of available data. Aim To develop and assess the impact of national SDs compared with GBD worldwide severity distributions for 21 cancer types. MethodsPatient-level records from the Scottish Cancer Registry for 21 cancers were obtained and linked to death registrations. We estimated prevalent cancer cases for 2016 and assigned each case to one of four phases (diagnosis and treatment; controlled; metastatic; and terminal) using GBD 2016 study definitions. SDs were calculated by considering relative proportions. The impact of choice of SDs was evaluated by comparing relative differences between weighted-average disability weights (DW) derived using GBD 2016 worldwide SDs with those derived from Scottish SDs. ResultsFor the majority of cancers the most prevalent phase was the controlled phase, which contributed a higher proportion than the combined proportion from the other three phases across all cancers except mesothelioma. Differences in the composition of severity meant that most point-estimates of Scottish severity proportions were out-with the 95% uncertainty intervals. These differences resulted in overestimates of weighted-average DWs based on GBD 2016 worldwide SDs (17 out of 21 cancer types). The largest relative overestimates were for gallbladder and biliary tract cancer, oesophageal cancer and pancreatic cancer (71%, 32% and 31% higher respectively). ConclusionThese findings illustrate a systematic bias introduced by using worldwide SDs. Current non-fatal BOD estimates should not be interpreted too precisely when comparing populations when they rely on data inputs from other countries. It is essential to ensure that any estimates are based upon country-specific data as far as possible.

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