The impact of vibrational Raman scattering of air on DOAS measurements of atmospheric trace gases

In remote sensing applications, such as differential optical absorption spectroscopy (DOAS), atmospheric scattering processes need to be considered. After inelastic scattering on N2 and O2 molecules, the scattered photons occur as additional intensity at a different wavelength, effectively leading to filling-in of both solar Fraunhofer lines and absorptions of atmospheric constituents. Measured spectra in passive DOAS applications are typically corrected for rotational Raman scattering (RRS), also called Ring effect, which represents the main contribution to inelastic scattering. In contrast to that, vibrational Raman scattering (VRS) of N2 and O2 has often been thought to be negligible, but also contributes. Consequences of VRS are red-shifted Fraunhofer structures in scattered light spectra and filling-in of Fraunhofer lines, additional to RRS. We describe how to calculate VRS correction spectra in analogy to the Ring spectrum. We discuss further the impact of VRS cross-sections for O2 and N2 on passive DOAS measurements. The relevance of VRS is shown for the first time in spectral evaluations of Multi-Axis DOAS data. This measurement data yields in agreement with calculated scattering cross-sections, that the observed VRS cross-section amounts to 2.2 ± 0.4% of the cross-section of RRS under tropospheric conditions. It is concluded, that this phenomenon has to be included in the spectral evaluation of weak absorbers as it reduces the measurement error significantly and can cause apparent differential optical depth of up to 2.5 × 10−4. Its influence on the spectral retrieval of IO, Glyoxal, water vapour and NO2 in the blue wavelength range is evaluated. For measurements with a large Ring signal a significant and systematic bias of NO2 dSCDs up to (−3.8 ± 0.4) × 1014 molec cm−2 at low elevation angles is observed if this effect is not considered

On the relative absorption strengths of water vapour in the blue wavelength range

In recent updates of the HITRAN water vapour H2O spectroscopic compilation covering the blue spectral region (here: 394–480 nm) significant changes for the absorption bands at 416 and 426 nm were reported. In order to investigate the consistency of the different cross-sections calculated from these compilations, H2O vapour column density ratios for different spectral intervals were retrieved from long-path and multi-axis differential optical absorption spectroscopy (DOAS) measurements. We observed a significant improvement of the DOAS evaluation when using the updated HITRAN water vapour absorption cross-sections for the calculation of the reference spectra. In particular the magnitudes of the residual spectra as well as the fit errors were reduced. However, we also found that the best match between measurement and model is reached when the absorption cross-section of groups of lines are scaled by factors ranging from 0.5 to 1.9, suggesting that the HITRAN water vapour absorption compilation still needs significant corrections. For this spectral region we present correction factors for HITRAN 2009, HITRAN 2012, HITEMP and BT2 derived from field measurements. Additionally, upper limits for water vapour absorption in the UV-A range from 330 to 390 nm are given

Retrieval interval mapping: a tool to visualize the impact of the spectral retrieval range on differential optical absorption spectroscopy evaluations

Remote sensing via differential optical absorption spectroscopy (DOAS) has become a standard technique to identify and quantify trace gases in the atmosphere. Due to the wide range of measurement conditions, atmospheric compositions and instruments used, a specific challenge of a DOAS retrieval is to optimize the retrieval parameters for each specific case and particular trace gas of interest. Of these parameters, the retrieval wavelength range is one of the most important ones. Although for many trace gases the overall dependence of common DOAS retrieval on the evaluation wavelength interval is known, a systematic approach for finding the optimal retrieval wavelength range and quantitative assessment is missing. Here we present a novel tool to visualize the effect of different evaluation wavelength ranges. It is based on mapping retrieved column densities in the retrieval wavelength space and thus visualizing the consequences of different choices of spectral retrieval ranges caused by slightly erroneous absorption cross sections, cross correlations and instrumental features. Based on the information gathered, an optimal retrieval wavelength range may be determined systematically

A new method for the identification of archaeological soils by their spectral signatures in the vis-NIR region

This paper introduces a statistical method to identify spectral signatures of buried archaeological remains and distinguish them from spectra of the background soil in the visible to near infrared region. The proposed method is based on the Principal Component Analysis (PCA). The difference between an archaeological spectrum and non-archaeological soil spectra is quantified by a so-called R value. R values larger than 1 indicate that the spectrum represents an archaeological material. The method is successfully applied to samples from five study sites in Italy and Hungary with special conditions. The reflection spectra are taken in a time-efficient way with a field spectrometer. The method works best if background non-archaeological soil spectra are gathered from the same area, around the targeted archaeological site. Also, it can work without such local background spectra (but with lower accuracy) using background spectra from existing spectral libraries. This indicates that the method can, in principle, be applied to any archaeological site which is spectrally distinct from its surroundings. The paper highlights that this method does not require high spectral resolution and thus has the advantage of using low spectral resolution spectrometers which can eventually be applied for continuous 2D imaging applications with high temporal resolution. Additional studies are needed to further improve the method and to investigate under which conditions it works well or only with limited accuracy

New horizons or a strategic mirage? Artist-led-distribution versus alliance strategy in the video game industry

In this paper we contribute to the debate between researchers who argue that the emergence of online distribution allows content producers in the creative industries to bypass powerful publishers and distributors, and other researchers who argue that this strategy cannot succeed without the complementary assets that these intermediaries provide. We use a case study of the Dutch Video Game Developer (DVGD) bringing to market an identical game using two different but comparable distribution channels as a quasi-experiment: in the first release DVGD used online distribution to reach consumers directly, whereas in the second it used an alliance with an established video game publisher. We find that, while the alliance required DVGD to share with the publisher a substantial fraction of the value appropriated by the game, the alliance strategy resulted in greater absolute financial performance and relative market performance compared to the self-publishing strategy. We conclude that the differences in performance can be traced back to specialized complementary assets required for successful commercialization

Emergence and Spread of ‘Unconferences’ as a New Temporary Organizational Form

Extant research mostly looks at the process of how temporary organizations proliferate within a single organization field. This study examines temporary organizations that emerge in one organizational field and are then introduced into other organizational fields. We argue that when this occurs, organizers must contend with the illegitimacy threat posed by temporary organizational forms that have long been institutionalized in the other fields. Organizers must decide whether they should accept the threat and retain the original form of the temporary organization, or whether they should modify the new temporary organizational form in order to make it more acceptable to audiences in other organizational fields. We argue that organizers will use legitimacy claims from the organizational field in which the temporary organization first emerged to mitigate the threat of illegitimacy. We further argue that the effectiveness of this strategy will depend on similarity in norms and beliefs between these fields: The more similar the organizational fields the more persuasive are the legitimacy claims, and the easier it is for the organizers to retain the form as it was first created; the more dissimilar are the organizational fields when it comes to norms and beliefs the harder it is for organizers to persuasively use these legitimacy claims, and the more organizers will have to modify the temporary organizational form to take account of audience expectations. We examine this using the case of the so called “unconferences”: an alternative conference form that emerged within the software development community at the start of the millennium in conjunction with the Web 2.0 movement. Our data comprises of 228 distinct unconferences between 2004 – when the unconference was first launched, and 2015. We examine the influence of organizational field dissimilarity of unconferences from the original field where it was first held, on the extent to which the pure unconference format is retained. We show that as adopters of the new form move away from the original organizational field, they are more likely to modify the original unconference form

Blame it on Hollywood: The Influence of Films on Paris as Product Location

This paper explores the way location myths conveyed through Hollywood movies influence consumer expectations, by looking at how the city of Paris is represented in motion pictures. We develop measures of the location image of Paris in a sample of Hollywood movies released between 1985 and 2011. These are used to examine the images of Paris held by American consumers who have never directly experienced the location. Our results show that Hollywood movies project specific location images and myths of Paris. More specifically, we show that these images fall into two distinct stereotypic patterns and are widely shared by consumers. Individuals who seek information on location from popular culture are shown to embrace and reproduce Paris myths. The study concludes that the cultural industries influence the cognitive consumption of location through the production and dissemination of meaning, via stories and fueled by perpetual myth making

A question of (mis)alignment: Innovation mandates and absorptive capacity routines

Research suggests that effective R&D requires the right combination ofinward-looking and outward-looking absorptive capacity routines. However, we do not have an adequate understanding of how these routines influence innovative output in R&D units with different mandates.In this paper, we argue that adopting an absorptive capacity routine would positively or negatively influence the R&D subsidiary’s innovative output, depending on whether the routine is aligned or misaligned with the subsidiary’s innovation mandate to ‘exploit’ existing knowledge or ‘explore’ new knowledge. We test this using data collected from a global packaged-software firm with 14 international R&D subsidiaries that implemented six major absorptive capacity routines in the period 2000-2010. Our research provides new insights for both scholars and practitioners in R&D management, by showing that balancing of absorptive capacity routines should be considered in light of innovation mandates of subsidiaries as well as the firm.Our analysis also provides insights on why decision-makers may still adopt misaligned routines