scholarly journals Ground-based FTIR measurements of CO from the Jungfraujoch: characterisation and comparison with <i>in situ</i> surface andMOPITT data

2003 ◽  
Vol 3 (5) ◽  
pp. 4857-4878 ◽  
Author(s):  
B. Barret ◽  
M. De Mazière ◽  
E. Mahieu
Keyword(s):  
Measurement Techniques ◽  
Vertical Profiles ◽  
Monthly Means ◽  
Positive Bias ◽  
Average Volume ◽  
Solar Absorption ◽  
Mixing Ratios ◽  
Significant Bias ◽  
Surface Measurements

Abstract. CO vertical profiles have been retrieved from solar absorption FTIR spectra recorded at the NDSC station of the Jungfraujoch (46.5° N, 8° E and 3580 m a.s.l.) for the period from January 1997 to May 2001. The characterisation of these profiles has been established by an information content analysis and an estimation of the error budgets. A partial validation of the profiles has been performed through comparisons with correlative measurements. The average volume mixing ratios (vmr) in the 3 km layer above the station have been compared with coincident surface measurements. The agreement between monthly means from both measurement techniques is very good, with a correlation coefficient of 0.87, and no significant bias observed. The FTIR total columns have also been compared to CO partial columns above 3580 m a.s.l. derived from the MOPITT (Measurement Of Pollution In The Troposphere) instrument for the period March 2000 to May 2001. Relative to the FTIR columns, the MOPITT partial columns exhibit a positive bias of 8±8% for daytime and of 4±7% for nighttime measurements.

scholarly journals Ground-based FTIR measurements of CO from the Jungfraujoch: characterisation and comparison with in situ surface and MOPITT data

2003 ◽  
Vol 3 (6) ◽  
pp. 2217-2223 ◽  
Author(s):  
B. Barret ◽  
M. De Mazière ◽  
E. Mahieu
Keyword(s):  
Measurement Techniques ◽  
Vertical Profiles ◽  
Monthly Means ◽  
Positive Bias ◽  
Average Volume ◽  
Solar Absorption ◽  
Mixing Ratios ◽  
Significant Bias ◽  
Surface Measurements

Abstract. CO vertical profiles have been retrieved from solar absorption FTIR spectra recorded at the NDSC station of the Jungfraujoch (46.5º N, 8º E and 3580 m a.s.l.) for the period from January 1997 to May 2001. The characterisation of these profiles has been established by an information content analysis and an estimation of the error budgets. A partial validation of the profiles has been performed through comparisons with correlative measurements. The average volume mixing ratios (vmr) in the 3 km layer above the station have been compared with coincident surface measurements. The agreement between monthly means from both measurement techniques is very good, with a correlation coefficient of 0.87, and no significant bias observed. The FTIR total columns have also been compared to CO partial columns above 3580 m a.s.l. derived from the MOPITT (Measurement Of Pollution In The Troposphere) instrument for the period March 2000 to May 2001. Relative to the FTIR columns, the MOPITT partial columns exhibit a positive bias of 8±8% for daytime and of 4±7% for nighttime measurements.

scholarly journals Vertical profiles of NO<sub>2</sub>, SO<sub>2</sub>, HONO, HCHO, CHOCHO, and aerosols derived from MAX-DOAS measurements at a rural site in the central-western North China Plain and their relation to emission sources and effects of regional transport

2018 ◽  
Author(s):  
Yang Wang ◽  
Steffen Dörner ◽  
Sebastian Donner ◽  
Sebastian Böhnke ◽  
Isabelle De Smedt ◽  
...  
Keyword(s):  
Trace Gases ◽  
Rural Site ◽  
Optical Absorption Spectroscopy ◽  
Vertical Profiles ◽  
Regional Transport ◽  
Near Surface ◽  
North West ◽  
Mixing Ratios ◽  
Chemistry Research

Abstract. A Multi Axis Differential Optical Absorption Spectroscopy (MAX-DOAS) instrument was deployed in May and June 2016 at a monitoring station (37.18° N, 114.36° E) in the suburban area of Xingtai (one of the most polluted cities in China) during the Atmosphere-Aerosol-Boundary Layer-Cloud (A2BC) and Air chemistry Research In Asia (ARIAs) joint experiments to derive tropospheric vertical profiles of NO2, SO2, HONO, HCHO, CHOCHO and aerosols. Aerosol optical depths derived from MAX-DOAS were found to be consistent with collocated sun-photometer measurements. Also the derived near-surface aerosol extinction and HCHO mixing ratio agree well with coincident visibility meter and in situ HCHO measurements, with mean HCHO near-surface mixing ratios of ~ 3.5 ppb. Underestimates of MAX-DOAS results compared to in situ measurements of NO2 (~ 60 %), SO2 (~ 20 %) are found expectedly due to vertical and horizontal inhomogeneity of trace gases. Vertical profiles of aerosols and NO2, SO2 are reasonably consistent with those measured by a collocated Raman Lidar and aircraft spirals over the station. The deviations can be attributed to differences in sensitivity as a function of altitude and substantial horizontal gradients of pollutants. Aerosols, HCHO, and CHOCHO profiles typically extended to higher altitudes (with 75 % integrated column located below ~ 1.4 km) than did NO2, SO2, and HONO (with 75 % integrated column below ~ 0.5 km) under polluted condition. Lifted layers were systematically observed for all species, (except HONO), indicating accumulation, secondary formation, or long-range transport of the pollutants at higher altitudes. Maximum values routinely occurred in the morning for NO2, SO2, and HONO, but around noon for aerosols, HCHO, and CHOCHO, mainly dominated by photochemistry, characteristic upslope/downslope circulation and PBL dynamics. Significant day-to-day variations are found for all species due to the effect of regional transport and changes in synoptic pattern analysed with HYSPLIT trajectories. Low pollution was often observed for air masses from the north-west (behind cold fronts), and high pollution from the southern areas such as industrialized Wuan. The contribution of regional transport for the pollutants measured at the site during the observation period was estimated to be about 20 % to 30 % for trace gases, and about 50 % for aerosols. In addition, agricultural burning events impacted the day-to-day variations of HCHO, CHOCHO and aerosols.

scholarly journals A framework for comparing remotely sensed and in-situ CO<sub>2</sub> concentrations

2008 ◽  
Vol 8 (1) ◽  
pp. 1549-1588 ◽  
Author(s):  
R. Macatangay ◽  
T. Warneke ◽  
C. Gerbig ◽  
S. Körner ◽  
R. Ahmadov ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Transport Model ◽  
Remotely Sensed ◽  
Infrared Spectrometry ◽  
Remotely Sensed Data ◽  
Solar Absorption ◽  
Mixing Ratios ◽  
In Situ Data ◽  
Global Calibration

Abstract. A framework that allows validating CO2 column averaged volume mixing ratios (VMRs) retrieved from ground-based solar absorption measurements using Fourier transform infrared spectrometry (FTS) against measurements made in-situ (such as from aircrafts and tall towers) has been developed. Since in-situ measurements are done frequently and at high accuracy on the global calibration scale, linking this scale with FTS total column retrievals ultimately provides a calibration scale for remote sensing. FTS, tower and aircraft data were analyzed from measurements during the CarboEurope Regional Experiment Strategy (CERES) from May to June 2005 in Biscarrosse, France. Carbon dioxide VMRs from the MetAir Dimona aircraft, the TM3 global transport model and Observations of the Middle Stratosphere (OMS) balloon based experiments were combined and integrated to compare with FTS measurements. The comparison agrees fairly well with differences resulting from the spatial variability of CO2 around the FTS as measured by the aircraft. Additionally, the Stochastic Time Inverted Lagrangian Transport (STILT) model served as a "transfer standard" between the in-situ data measured at a co-located tower and the remotely sensed data from the FTS. The variability of carbon dioxide VMRs was modeled well by STILT with differences coming partly from uncertainties in the spatial variation of carbon dioxide.

scholarly journals In situ measurement of CO<sub>2</sub> and CH<sub>4</sub> from aircraft over northeast China and comparison with OCO-2 data

2019 ◽  
Author(s):  
Xiaoyu Sun ◽  
Minzheng Duan ◽  
Yang Gao ◽  
Rui Han ◽  
Denghui Ji ◽  
...  
Keyword(s):  
Greenhouse Gases ◽  
Northeast China ◽  
In Situ Measurements ◽  
Vertical Profiles ◽  
Large Area ◽  
Mixing Ratios ◽  
Swir Band ◽  
Shortwave Infrared ◽  
The Vertical Distribution

Abstract. Several satellites have been launched to monitor the increasing concentrations of greenhouse gases, especially CO2 and CH4 in the atmosphere, through back-scattered hyperspectral radiance in the shortwave infrared (SWIR) band. The vertical profiles of greenhouse gases and aerosol could strongly affect the results from these instruments. To investigate the effects of the vertical distribution of CO2 on uncertainty in SWIR satellite retrieval results, we conducted observations of the vertical profiles of CO2, CH4, and aerosol particles at 0.6–7 km above sea level using a Beechcraft King Air 350ER in Jiansanjiang (46.77° N, 131.99° E), Heilongjiang province, Northeast China, on August 7–12, 2018. The profiles from this aircraft captured a decrease in CO2 from 2 km to the minimum altitude due to uptake from vegetation at the surface in summer. CH4 measurements showed an average 0.5 ppm increase from 2.0 to 0.6 km, which may result from emissions from the large area of paddy fields below, and a constant mole fraction between 1.951 and 1.976 ppm was recorded at 2 km and above. Comparison of CO2 profiles from a new version of the carbon cycle data assimilation system Tan-Tracker (v1), retrievals from OCO-2 and aircraft measurements was conducted. The results from OCO-2 and the assimilation model system Tan-Tracker captured the vertical structure of CO2 above 3 km, whereas below 3 km, the values from OCO-2 and Tan-Tracker model were lower than those from in situ measurements. Column-averaged CO2 volume mixing ratios calculated from in situ measurements showed biases of −2.39 ± 2.02 ppm and −0.61 ± 0.49 % compared to OCO-2 retrievals.

scholarly journals Halogen Occultation Experiment (HALOE) and balloon-borne in situ measurements of methane in stratosphere and their relation to the quasi-biennial oscillation (QBO)

2003 ◽  
Vol 3 (4) ◽  
pp. 1051-1062 ◽  
Author(s):  
P. K. Patra ◽  
S. Lal ◽  
S. Venkataramani ◽  
D. Chand
Keyword(s):  
Transport Model ◽  
Measurement Techniques ◽  
Vertical Profiles ◽  
Quasi Biennial Oscillation ◽  
Chemistry Transport Model ◽  
The Tropics ◽  
Biennial Oscillation ◽  
Good Agreement ◽  
Balloon Measurements

Abstract. Measurements of methane have been made from various observational platforms in the atmosphere. In this article, we have compared four high precision balloon-borne measurements from Hyderabad (17.5°N), India in the period of 1987 and 1998 with a part of HALOE/UARS global observations available since 1991. All the balloon measurements correspond to boreal spring (March and April) but belong to different years. A comparison shows fairly good agreement with each other. The gradient in CH4 profiles in the troposphere is controlled by the variation in vertical transport. The strongest effect of dynamical influence on methane vertical profiles is shown to be resulting from the dynamical quasi-biennial oscillation in the stratosphere, and that has been consistently derived from both the measurement techniques and chemistry-transport model simulations. It is observed that the QBO signal in CH4 anomaly exhibits interhemispheric asymmetry caused by the tropics to midlatitude circulation in the stratosphere. A mechanism is suggested to explain how and to what extent the methane vertical profiles over Hyderabad and higher latitudes could be modulated by the prevailing QBO winds in the tropics. We have also discussed how the same mechanism would affect ozone distribution in the stratosphere quite differently.

scholarly journals 1997–2007 CO trend at the high Alpine site Jungfraujoch: a comparison between NDIR surface in situ and FTIR remote sensing observations

2011 ◽  
Vol 11 (13) ◽  
pp. 6735-6748 ◽  
Author(s):  
B. Dils ◽  
J. Cui ◽  
S. Henne ◽  
E. Mahieu ◽  
M. Steinbacher ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Sea Level ◽  
Measurement Techniques ◽  
Surface Concentration ◽  
Infrared Spectrometry ◽  
Research Station ◽  
Strong Impact ◽  
Solar Absorption ◽  
Combining Data

Abstract. Within the atmospheric research community, there is a strong interest in integrated datasets, combining data from several instrumentations. This integration is complicated by the different characteristics of the datasets, inherent to the measurement techniques. Here we have compared two carbon monoxide time series (1997 till 2007) acquired at the high-Alpine research station Jungfraujoch (3580 m above sea level), with two well-established measurement techniques, namely in situ surface concentration measurements using Non-Dispersive Infrared Absorption technology (NDIR), and ground-based remote sensing measurements using solar absorption Fourier Transform Infrared spectrometry (FTIR). The profile information available in the FTIR signal allowed us to extract an independent layer with a top height of 7.18 km above sea level, appropriate for comparison with our in situ measurements. We show that, even if both techniques are able to measure free troposphere CO concentrations, the datasets exhibit marked differences in their overall trends (−3.21 ± 0.03 ppb year−1 for NDIR vs. −0.8 ± 0.4 ppb year−1 for FTIR). Removing measurements that are polluted by uprising boundary layer air has a strong impact on the NDIR trend (now −2.62 ± 0.03 ppb year−1), but its difference with FTIR remains significant. Using the LAGRANTO trajectory model, we show that both measurement techniques are influenced by different source regions and therefore are likely subject to exhibit significant differences in their overall trend behaviour. However the observation that the NDIR-FTIR trend difference is as significant before as after 2001 is at odds with available emission databases which claim a significant Asian CO increase after 2001 only.

scholarly journals Diagnostics of the Tropical Tropopause Layer from in-situ observations and CCM data

2009 ◽  
Vol 9 (3) ◽  
pp. 11659-11698
Author(s):  
E. Palazzi ◽  
F. Fierli ◽  
F. Cairo ◽  
C. Cagnazzo ◽  
G. Di Donfrancesco ◽  
...  
Keyword(s):  
Vertical Structure ◽  
Climate Model ◽  
Joint Analysis ◽  
Vertical Profiles ◽  
Transport Barrier ◽  
Tropical Tropopause Layer ◽  
Mixing Ratios ◽  
Tropical Tropopause ◽  
Scatter Plots

Abstract. A suite of diagnostics is applied to in-situ aircraft measurements and one Chemistry-Climate Model (CCM) data to characterize the vertical structure of the Tropical Tropopause Layer (TTL). The diagnostics are based on the vertical tracers profiles, relative vertical tracers gradients, and tracer-tracer relationships in the tropical Upper Troposphere/Lower Stratosphere (UT/LS), using tropopause coordinates. Observations come from the four tropical campaigns performed from 1998 to 2006 with the research aircraft Geophysica and have been directly compared to the output of the ECHAM5/MESSy CCM. The model vertical resolution in the TTL allows for appropriate comparison with high-resolution aircraft observations and the diagnostics used highlight common TTL features between the model and the observational data. The analysis of the vertical profiles of water vapour, ozone, and nitrous oxide, in both the observations and the model, shows that concentration mixing ratios exhibit a strong gradient change across the tropical tropopause, due to the role of this latter as a transport barrier and that transition between the tropospheric and stratospheric regimes occurs within a finite layer. The use of relative vertical ozone gradients, in addition to the vertical profiles, helps to highlight the region where this transition occurs and allows to give an estimate of its thickness. The analysis of the CO-O3 and H2O-O3 scatter plots and of the Probability Distribution Function (PDF) of the H2O-O3 pair completes this picture as it allows to better distinguish tropospheric and stratospheric regimes that can be identified, first, by their differing chemical composition. The joint analysis and comparison of observed and modelled data allows us to evaluate the capability of the model in reproducing the observed vertical structure of the TTL and its variability, and also to assess whether observations from particular regions on a monthly timescale can be representative of the fine scale mean structure of the Tropical Tropopause Layer.

scholarly journals Development of a balloon-borne instrument for CO<sub>2</sub> vertical profile observations in the troposphere

2019 ◽  
Author(s):  
Mai Ouchi ◽  
Yutaka Matsumi ◽  
Tomoki Nakayama ◽  
Kensaku Shimizu ◽  
Takehiko Sawada ◽  
...  
Keyword(s):  
Field Experiments ◽  
Co2 Concentration ◽  
Observation System ◽  
Vertical Profiles ◽  
Mixing Ratios ◽  
The Difference ◽  
Carbon Dioxide Co2 ◽  
First Time ◽  
Aircraft Data

Abstract. A novel, practical observation system for measuring tropospheric carbon dioxide (CO2) concentrations using a non-dispersive infrared analyzer carried by a small helium-filled balloon (CO2 sonde), has been developed for the first time. Onboard calibrations, using CO2 standard gases, is possible to measure the vertical profiles of atmospheric CO2 accurately with a 240–400 m altitude resolution. The standard deviations (1σ) of the measured mixing ratios in the laboratory experiments using a vacuum chamber at a temperature of 298 K were approximately 0.6 ppm at 1010 hPa and 1.2 ppm at 250 hPa. Compared with in situ aircraft data, although the difference up to the altitude of 7 km was 0.6 ± 1.2 ppm, this bias and difference were within the precision of the CO2 sonde. In field experiments, the CO2 sonde detected an increase in CO2 concentration in an urban area and a decrease in a forested area near the surface. The CO2 sonde was shown to be a useful instrument for observing and monitoring the vertical profiles of CO2 concentration in the troposphere.

scholarly journals 1997–2007 CO trend at the high Alpine site Jungfraujoch: a comparison between NDIR surface in situ and FTIR remote sensing observations

2011 ◽  
Vol 11 (3) ◽  
pp. 8977-9017
Author(s):  
B. Dils ◽  
J. Cui ◽  
S. Henne ◽  
E. Mahieu ◽  
M. Steinbacher ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Measurement Techniques ◽  
Surface Concentration ◽  
Infrared Spectrometry ◽  
Research Station ◽  
Solar Absorption ◽  
Combining Data ◽  
Alpine Research ◽  
Different Characteristics

Abstract. Within the atmospheric research community, there is a strong interest in integrated datasets, combining data from several instrumentations. This integration is complicated by the different characteristics of the datasets, inherent to the measurement techniques. Here we have compared two carbon monoxide time series (1997 till 2007) acquired at the high-Alpine research station Jungfraujoch, with two well-established measurement techniques, namely in situ surface concentration measurements using Non-Dispersive Infrared Absorption technology (NDIR), and ground-based remote sensing measurements using solar absorption Fourier Transform Infrared spectrometry (FTIR). We show that, even if both techniques are able to measure free troposphere CO concentrations, the datasets are influenced by different source regions and therefore are subject to exhibit significant differences in their overall trend behaviour.

scholarly journals High resolution vertical distributions of NO<sub>3</sub> and N<sub>2</sub>O<sub>5</sub> through the nocturnal boundary layer

2007 ◽  
Vol 7 (1) ◽  
pp. 139-149 ◽  
Author(s):  
S. S. Brown ◽  
W. P. Dubé ◽  
H. D. Osthoff ◽  
D. E. Wolfe ◽  
W. M. Angevine ◽  
...  
Keyword(s):  
High Resolution ◽  
Nitrogen Oxides ◽  
Nocturnal Boundary Layer ◽  
Vertical Profiles ◽  
Surface Layers ◽  
Mixing Depth ◽  
Near Surface ◽  
Mixing Ratios ◽  
Vertical Distributions

Abstract. The shallow mixing depth and vertical stratification of the lowest levels of the atmosphere at night has implications for the chemistry of nitrogen oxides emitted from the surface. Here we report vertical profiles of NO3, N2O5 and O3 measured from in-situ instruments on a movable carriage on a 300 m tower. The study offers high-resolution (<1 m) vertical distributions of both NO3 and N2O5 and shows that the nocturnal mixing ratios of these compounds vary widely over short vertical distance scales (10 m or less). Furthermore, there are systematic differences in the steady state lifetimes of NO3 and N2O5 and in the partitioning among nitrogen oxides between different near-surface layers. These differences imply that NO3 and N2O5 occupy distinct chemical regimes as a function of altitude, potentially serving as sinks for nitrogen oxides and O3 near the surface but as reservoirs of NOx and O3 aloft.

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