This paper describes the contents of the 2016 edition of the HITRAN molecular spectroscopic compilation. The new edition replaces the previous HITRAN edition of 2012 and its updates during the intervening years. The HITRAN molecular absorption compilation is composed of five major components: the traditional line-by-line spectroscopic parameters required for high-resolution radiative-transfer codes, infrared absorption cross-sections for molecules not yet amenable to representation in a line-by-line form, collision-induced absorption data, aerosol indices of refraction, and general tables such as partition sums that apply globally to the data. The new HITRAN is greatly extended in terms of accuracy, spectral coverage, additional absorption phenomena, added line-shape formalisms, and validity. Moreover, molecules, isotopologues, and perturbing gases have been added that address the issues of atmospheres beyond the Earth. Of considerable note, experimental IR cross-sections for almost 300 additional molecules important in different areas of atmospheric science have been added to the database. The compilation can be accessed through www.hitran.org. Most of the HITRAN data have now been cast into an underlying relational database structure that offers many advantages over the long-standing sequential text-based structure. The new structure empowers the user in many ways. It enables the incorporation of an extended set of fundamental parameters per transition, sophisticated line-shape formalisms, easy user-defined output formats, and very convenient searching, filtering, and plotting of data. A powerful application programming interface making use of structured query language (SQL) features for higher-level applications of HITRAN is also provided.

/pdf/the-hitran-2008-molecular-spectroscopic-database-1ud8clpej3.pdf

The HITRAN 2008 molecular spectroscopic database

Changes in Atmospheric Constituents and in Radiative Forcing

A fast-Fourier-transform method of topography and interferometry is proposed. By computer processing of a noncontour type of fringe pattern, automatic discrimination is achieved between elevation and depression of the object or wave-front form, which has not been possible by the fringe-contour-generation techniques. The method has advantages over moire topography and conventional fringe-contour interferometry in both accuracy and sensitivity. Unlike fringe-scanning techniques, the method is easy to apply because it uses no moving components.

Fourier-transform method of fringe-pattern analysis for computer-based topography and interferometry

Secondary organic aerosol (SOA) accounts for a significant fraction of ambient tropospheric aerosol and a detailed knowledge of the formation, properties and transformation of SOA is therefore required to evaluate its impact on atmospheric processes, climate and human health. The chemical and physical processes associated with SOA formation are complex and varied, and, despite considerable progress in recent years, a quantitative and predictive understanding of SOA formation does not exist and therefore represents a major research challenge in atmospheric science. This review begins with an update on the current state of knowledge on the global SOA budget and is followed by an overview of the atmospheric degradation mechanisms for SOA precursors, gas-particle partitioning theory and the analytical techniques used to determine the chemical composition of SOA. A survey of recent laboratory, field and modeling studies is also presented. The following topical and emerging issues are highlighted and discussed in detail: molecular characterization of biogenic SOA constituents, condensed phase reactions and oligomerization, the interaction of atmospheric organic components with sulfuric acid, the chemical and photochemical processing of organics in the atmospheric aqueous phase, aerosol formation from real plant emissions, interaction of atmospheric organic components with water, thermodynamics and mixtures in atmospheric models. Finally, the major challenges ahead in laboratory, field and modeling studies of SOA are discussed and recommendations for future research directions are proposed.

/pdf/the-formation-properties-and-impact-of-secondary-organic-4x4th6v9ke.pdf

The formation, properties and impact of secondary organic aerosol: current and emerging issues

The talk with present the key results of the IPCC Working Group III 5th assessment report. Concluding four years of intense scientific collaboration by hundreds of authors from around the world, the report responds to the request of the world's governments for a comprehensive, objective and policy neutral assessment of the current scientific knowledge on mitigating climate change. The report has been extensively reviewed by experts and governments to ensure quality and comprehensiveness.

Climate change 2014 - Mitigation of climate change

Here we describe a new method for the quantification of a global NOx budget from image sequences of the GOME instrument on the ERS-2. The focus of this paper is on image processing techniques to separate tropospheric and stratospheric NO2-colums using normalized convolution with infinite impulse response filters (IIR) to interpolate gaps in the data and average the cloud coverage of the earth, the estimation the NO2 life time and the determination of regional NOx source strengths.

Image Sequence Analysis of Satellite NO2 Concentration Maps

The invention relates to a method and to a device for calibrating an optical resonator. The method comprises the following steps: generating light pulses of a known pulse frequency by means of a light-pulse generation unit; coupling the light pulses into the resonator (20); detecting light exiting the resonator (20) by means of a detection apparatus in order to generate a detection signal, wherein the detection apparatus is designed to generate the detection signal by means of a modulator as a signal modulated with a modulation frequency, wherein the modulation frequency is substantially equal to the pulse frequency of the generated light pulses or wherein the modulation frequency is substantially an integer multiple of the pulse frequency of the generated light pulses or wherein the pulse frequency of the generated light pulses is substantially an integer multiple of the modulation frequency; and calibrating the optical resonator (20) on the basis of the detection signal. The invention further relates to a use of the device according to the invention, to a use of a switchable detector or of an optical modulator, and to a computer program product.

Method and device for calibrating an optical resonator, use of the device, use of an optical modulator, and computer program product

Bei der Selbstreinigung der Atmosphare von Fremdstoffen, die durch menschliche, aber auch naturliche Aktivitaten in die Atmosphare gelangen, spielen sogenannte freie Radikale eine zentrale Rolle. Bereits in geringsten Spuren (ein Radikal auf 1013 Luftmolekule) entfalten sie ihre Wirkung. Diese extreme Seltenheit der Teilchen erklart auch, das Radikale — obwohl seit Jahrzehnten postuliert — erst in jungster Zeit durch neue physikalische Mesverfahren eindeutig in der Umgebungsluft nachgewiesen werden konnten.

https://www.onlinelibrary.wiley.com/doi/pdf/10.1002/phbl.19990550112

Freie Radikale — die treibende Kraft der Stoffumsetzungen in der Atmosphäre

. Monitoring of NO2 is in the interest of public health, because NO2 contributes to the decline of air quality in many urban regions. Its abundance can be a direct cause of asthmatic and cardiovascular diseases and plays a significant part in forming other pollutants such as ozone or particulate matter. Spectroscopic methods have proven to be reliable and of high selectivity by utilizing the characteristic spectral absorption signature of trace gasses such as NO2. However, they typically lack the spatio-temporal resolution required for real-time imaging measurements of NO2 emissions. We propose imaging measurements of NO2 in the visible spectral range using a novel instrument, an NO2 camera based on the principle of Gas Correlation Spectroscopy (GCS). For this purpose two gas cells (cuvettes) are placed in front of two camera modules. One gas cell is empty, while the other is filled with a high concentration of the target gas. The filled gas cell operates as a non-dispersive spectral filter to the incoming light, maintaining the two-dimensional imaging capability of the sensor arrays. NO2 images are generated on the basis of the signal ratio between the two images in the spectral window between 430 and 445 nm, where the NO2 absorption cross section is strongly structured. The capabilities and limits of the instrument are investigated in a numerical forward model. The predictions of this model are verified in a proof-of-concept measurement, in which the column densities in specially prepared reference cells were measured with the NO2 camera and a conventional DOAS instrument. Finally, results from measurements at a large power plant, the Groskraftwerk Mannheim (GKM), are presented. NO2 column densities of the plume emitted from a GKM chimney are quantified at a spatio-temporal resolution of 1/6 frames per second (FPS) and 0.92 m × 0.92 m. A detection limit of 1.89 · 1016 molec cm−2 was reached. An NO2 mass flux of Fm = (7.41 ± 4.23) kg h−1 was estimated on the basis of momentary wind speeds obtained from consecutive images. The camera results are verified by comparison to NO2 slant column densities obtained from elevation scans with a MAX-DOAS instrument. The instrument prototype is highly portable and cost-efficient at building costs of below 2,000 Euro.

/pdf/the-no-2-camera-based-on-gas-correlation-spectroscopy-10k97r8vu4.pdf

Ulrich Platt

Papers

Image Sequence Analysis of Satellite NO2 Concentration Maps

Method and device for calibrating an optical resonator, use of the device, use of an optical modulator, and computer program product

Freie Radikale — die treibende Kraft der Stoffumsetzungen in der Atmosphäre

The NO 2 camera based on Gas Correlation Spectroscopy

Part I. Phenol formation under atmospheric conditions