Quantitative Spectroscopy and Atmospheric Measurements

2007 ◽  
pp. 107-121 ◽  
Author(s):  
J. -M. Flaud ◽  
A. Perrin ◽  
B. Picquet-Varrault ◽  
A. Gratien ◽  
J. Orphal ◽  
...  
Keyword(s):  
Atmospheric Measurements ◽  
Quantitative Spectroscopy

Spectroscopy Fundamentals

2017 ◽  
Author(s):  
Kelly Chance ◽  
Randall V. Martin
Keyword(s):  
Vibrational Spectroscopy ◽  
Cross Sections ◽  
Nuclear Spin ◽  
Electronic Spectroscopy ◽  
Rotational Spectroscopy ◽  
Absorption Cross ◽  
Transfer Processes ◽  
Atmospheric Spectroscopy ◽  
Quantitative Spectroscopy ◽  
Broad Overview

This chapter provides a broad overview of the spectroscopic principles required in order to perform quantitative spectroscopy of atmospheres. It couples the details of atmospheric spectroscopy with the radiative transfer processes and also with the assessment of rotational, vibrational, and electronic spectroscopic measurements of atmospheres. The principles apply from line-resolved measurements (chiefly microwave through infrared) through ultraviolet and visible measurements employing absorption cross sections developed from individual transitions. The chapter introduces Einstein coefficients before in turn discussing rotational spectroscopy, vibrational spectroscopy, nuclear spin, and electronic spectroscopy.

scholarly journals Decadal increase in Arctic dimethylsulfide emission

2019 ◽  
Vol 116 (39) ◽  
pp. 19311-19317 ◽  
Author(s):  
Martí Galí ◽  
Emmanuel Devred ◽  
Marcel Babin ◽  
Maurice Levasseur
Keyword(s):  
Sea Ice ◽  
Radiative Forcing ◽  
Positive Trend ◽  
Aerosol Formation ◽  
Atmospheric Measurements ◽  
Sea Ice Extent ◽  
Phytoplankton Productivity ◽  
Physical Forcing ◽  
Ice Retreat ◽  
Aerosol Cloud Interactions

Dimethylsulfide (DMS), a gas produced by marine microbial food webs, promotes aerosol formation in pristine atmospheres, altering cloud radiative forcing and precipitation. Recent studies suggest that DMS controls aerosol formation in the summertime Arctic atmosphere and call for an assessment of pan-Arctic DMS emission (EDMS) in a context of dramatic ecosystem changes. Using a remote sensing algorithm, we show that summertime EDMS from ice-free waters increased at a mean rate of 13.3 ± 6.7 Gg S decade−1 (∼33% decade−1) north of 70°N between 1998 and 2016. This trend, mostly explained by the reduction in sea-ice extent, is consistent with independent atmospheric measurements showing an increasing trend of methane sulfonic acid, a DMS oxidation product. Extrapolation to an ice-free Arctic summer could imply a 2.4-fold (±1.2) increase in EDMS compared to present emission. However, unexpected regime shifts in Arctic geo- and ecosystems could result in future EDMS departure from the predicted range. Superimposed on the positive trend, EDMS shows substantial interannual changes and nonmonotonic multiyear trends, reflecting the interplay between physical forcing, ice retreat patterns, and phytoplankton productivity. Our results provide key constraints to determine whether increasing marine sulfur emissions, and resulting aerosol–cloud interactions, will moderate or accelerate Arctic warming in the context of sea-ice retreat and increasing low-level cloud cover.

scholarly journals On the vertical distribution of smoke in the Amazonian atmosphere during the dry season

2016 ◽  
Vol 16 (4) ◽  
pp. 2155-2174 ◽  
Author(s):  
Franco Marenco ◽  
Ben Johnson ◽  
Justin M. Langridge ◽  
Jane Mulcahy ◽  
Angela Benedetti ◽  
...  
Keyword(s):  
Vertical Structure ◽  
Atmospheric Measurements ◽  
Extinction Coefficients ◽  
Smoke Plumes ◽  
Model Predictions ◽  
Research Aircraft ◽  
The Vertical Distribution ◽  
Lidar Observations ◽  
Aerosol Extinction Coefficient ◽  
Assimilation System

Abstract. Lidar observations of smoke aerosols have been analysed from six flights of the Facility for Airborne Atmospheric Measurements BAe-146 research aircraft over Brazil during the biomass burning season (September 2012). A large aerosol optical depth (AOD) was observed, typically ranging 0.4–0.9, along with a typical aerosol extinction coefficient of 100–400 Mm−1. The data highlight the persistent and widespread nature of the Amazonian haze, which had a consistent vertical structure, observed over a large distance ( ∼ 2200 km) during a period of 14 days. Aerosols were found near the surface; but the larger aerosol load was typically found in elevated layers that extended from 1–1.5 to 4–6 km. The measurements have been compared to model predictions with the Met Office Unified Model (MetUM) and the ECMWF-MACC model. The MetUM generally reproduced the vertical structure of the Amazonian haze observed with the lidar. The ECMWF-MACC model was also able to reproduce the general features of smoke plumes albeit with a small overestimation of the AOD. The models did not always capture localised features such as (i) smoke plumes originating from individual fires, and (ii) aerosols in the vicinity of clouds. In both these circumstances, peak extinction coefficients of the order of 1000–1500 Mm−1 and AODs as large as 1–1.8 were encountered, but these features were either underestimated or not captured in the model predictions. Smoke injection heights derived from the Global Fire Assimilation System (GFAS) for the region are compatible with the general height of the aerosol layers.

scholarly journals Verification of greenhouse gas emission reductions: the prospect of atmospheric monitoring in polluted areas

2011 ◽  
Vol 369 (1943) ◽  
pp. 1906-1924 ◽  
Author(s):  
Ingeborg Levin ◽  
Samuel Hammer ◽  
Elke Eichelmann ◽  
Felix R. Vogel
Keyword(s):  
Greenhouse Gas Emissions ◽  
Greenhouse Gas ◽  
Catchment Area ◽  
Greenhouse Gas Emission ◽  
Atmospheric Transport ◽  
Atmospheric Measurements ◽  
Transport Modelling ◽  
Gas Emissions ◽  
Atmospheric Transport Modelling

Independent verification of greenhouse gas emissions reporting is a legal requirement of the Kyoto Protocol, which has not yet been fully accomplished. Here, we show that dedicated long-term atmospheric measurements of greenhouse gases, such as carbon dioxide (CO 2 ) and methane (CH 4 ), continuously conducted at polluted sites can provide the necessary tool for this undertaking. From our measurements at the semi-polluted Heidelberg site in the upper Rhine Valley, we find that in the catchment area CH 4 emissions decreased on average by 32±6% from the second half of the 1990s until the first half of the 2000s, but the observed long-term trend of emissions is considerably smaller than that previously reported for southwest Germany. In contrast, regional fossil fuel CO 2 levels, estimated from high-precision 14 CO 2 observations, do not show any significant decreasing trend since 1986, in agreement with the reported emissions for this region. In order to provide accurate verification, these regional measurements would best be accompanied by adequate atmospheric transport modelling as required to precisely determine the relevant catchment area of the measurements. Furthermore, reliable reconciliation of reported emissions will only be possible if these are known at high spatial resolution in the catchment area of the observations. This information should principally be available in all countries that regularly report their greenhouse gas emissions to the United Nations Framework Convention on Climate Change.

Atmospheric measurements of aerosol precursor gases in the upper troposphere and lower stratosphere

1997 ◽  
Vol 28 ◽  
pp. S65-S66 ◽  
Author(s):  
F. Arnold ◽  
K.H. Wohlfrom ◽  
J. Schneider ◽  
M. Klemm ◽  
T. Stilp ◽  
...  
Keyword(s):  
Lower Stratosphere ◽  
Atmospheric Measurements ◽  
Upper Troposphere
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