scholarly journals Inter-comparison of MAX-DOAS measurements of tropospheric HONO slant column densities and vertical profiles during the CINDI-2 Campaign

2020 ◽  
Author(s):  
Yang Wang ◽  
Arnoud Apituley ◽  
Alkiviadis Bais ◽  
Steffen Beirle ◽  
Nuria Benavent ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Estimation Method ◽  
Optimal Estimation ◽  
Early Morning ◽  
Radiative Transfer Model ◽  
Measuring Instruments ◽  
Transfer Model ◽  
Vertical Profiles ◽  
Near Surface ◽  
Profile Inversion

Abstract. We present the inter-comparison of delta slant column densities (SCDs) and vertical profiles of nitrous acid (HONO) derived from measurements of different MAX-DOAS instruments and using different inversion algorithms during the Second Cabauw Inter-comparison campaign for Nitrogen Dioxide measuring Instruments (CINDI-2), in September 2016, at Cabauw, The Netherlands (51.97° N, 4.93° E). Systematic discrepancies of HONO delta SCDs are observed in the range of ±0.3 × 1015 molecules cm−2, which is half of the typical random discrepancy of 0.6 × 1015 molecules cm−2. For a typical high HONO delta SCD of 2 × 1015 molecules cm−2, the relative systematic and random discrepancies are about 15 % and 30 %, respectively. The inter-comparison of HONO profiles shows that both systematic and random discrepancies of HONO VCDs and near-surface volume mixing ratios (VMRs) are mostly in the range of ~ ±0.5 × 1015 molecules cm−2 and ~ ±0.1 ppb (typically ~ 20 %). Further we find that the discrepancies of the retrieved HONO profiles are dominated by discrepancies of the HONO delta SCDs. The profile retrievals only contribute to the discrepancies of the HONO profiles by ~ 5 %. However, some data sets with substantial larger discrepancies than the typical values indicate that inappropriate implementations of profile inversion algorithms and configurations of radiative transfer models in the profile retrievals can also be an important uncertainty source. In addition, estimations of measurement uncertainties of HONO dSCDs, which can significantly impact profile retrievals using the optimal estimation method, need to consider not only DOAS fit errors, but also atmospheric variability, especially for an instrument with a DOAS fit error lower than ~ 3 × 1015 molecules cm−2. The MAX-DOAS results during the CINDI-2 campaign indicate that the peak HONO levels (e.g. near-surface VMRs of ~ 0.4 ppb) often appeared in the early morning and below 0.2 km. The near-surface VMRs retrieved from the MAX-DOAS observations are compared with those measured using a co-located long-path DOAS instrument. The systematic differences are smaller than 0.15 ppb and 0.07 ppb during early morning and around noon, respectively. Since true HONO values at high altitudes are not known in the absence of real measurements, in order to evaluate the abilities of profile inversion algorithms to respond to different HONO profile shapes, we performed sensitivity studies using synthetic HONO delta SCDs simulated by a radiative transfer model with assumed HONO profiles. The tests indicate that the profile inversion algorithms based on the optimal estimation method with proper configurations can well reproduce the different HONO profile shapes. Therefore we conclude that the feature of HONO accumulated near the surface derived from MAX-DOAS measurements are expected to well represent the ambient HONO profiles.

scholarly journals Inter-comparison of MAX-DOAS measurements of tropospheric HONO slant column densities and vertical profiles during the CINDI-2 campaign

2020 ◽  
Vol 13 (9) ◽  
pp. 5087-5116 ◽  
Author(s):  
Yang Wang ◽  
Arnoud Apituley ◽  
Alkiviadis Bais ◽  
Steffen Beirle ◽  
Nuria Benavent ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Estimation Method ◽  
Optimal Estimation ◽  
Early Morning ◽  
Optical Absorption Spectroscopy ◽  
Data Sets ◽  
Vertical Profiles ◽  
Near Surface ◽  
Mixing Ratios ◽  
Profile Inversion

Abstract. We present the inter-comparison of delta slant column densities (SCDs) and vertical profiles of nitrous acid (HONO) derived from measurements of different multi-axis differential optical absorption spectroscopy (MAX-DOAS) instruments and using different inversion algorithms during the Second Cabauw Inter-comparison campaign for Nitrogen Dioxide measuring Instruments (CINDI-2) in September 2016 at Cabauw, the Netherlands (51.97∘ N, 4.93∘ E). The HONO vertical profiles, vertical column densities (VCDs), and near-surface volume mixing ratios are compared between different MAX-DOAS instruments and profile inversion algorithms for the first time. Systematic and random discrepancies of the HONO results are derived from the comparisons of all data sets against their median values. Systematic discrepancies of HONO delta SCDs are observed in the range of ±0.3×1015 molec. cm−2, which is half of the typical random discrepancy of 0.6×1015 molec. cm−2. For a typical high HONO delta SCD of 2×1015 molec. cm−2, the relative systematic and random discrepancies are about 15 % and 30 %, respectively. The inter-comparison of HONO profiles shows that both systematic and random discrepancies of HONO VCDs and near-surface volume mixing ratios (VMRs) are mostly in the range of ∼±0.5×1014 molec. cm−2 and ∼±0.1 ppb (typically ∼20 %). Further we find that the discrepancies of the retrieved HONO profiles are dominated by discrepancies of the HONO delta SCDs. The profile retrievals only contribute to the discrepancies of the HONO profiles by ∼5 %. However, some data sets with substantially larger discrepancies than the typical values indicate that inappropriate implementations of profile inversion algorithms and configurations of radiative transfer models in the profile retrievals can also be an important uncertainty source. In addition, estimations of measurement uncertainties of HONO dSCDs, which can significantly impact profile retrievals using the optimal estimation method, need to consider not only DOAS fit errors, but also atmospheric variability, especially for an instrument with a DOAS fit error lower than ∼3×1014 molec. cm−2. The MAX-DOAS results during the CINDI-2 campaign indicate that the peak HONO levels (e.g. near-surface VMRs of ∼0.4 ppb) often appeared in the early morning and below 0.2 km. The near-surface VMRs retrieved from the MAX-DOAS observations are compared with those measured using a co-located long-path DOAS instrument. The systematic differences are smaller than 0.15 and 0.07 ppb during early morning and around noon, respectively. Since true HONO values at high altitudes are not known in the absence of real measurements, in order to evaluate the abilities of profile inversion algorithms to respond to different HONO profile shapes, we performed sensitivity studies using synthetic HONO delta SCDs simulated by a radiative transfer model with assumed HONO profiles. The tests indicate that the profile inversion algorithms based on the optimal estimation method with proper configurations can reproduce the different HONO profile shapes well. Therefore we conclude that the features of HONO accumulated near the surface derived from MAX-DOAS measurements are expected to represent the ambient HONO profiles well.

scholarly journals Vertical profile of tropospheric ozone derived from synergetic retrieval using three different wavelength ranges, UV, IR, and microwave: sensitivity study for satellite observation

2018 ◽  
Vol 11 (3) ◽  
pp. 1653-1668 ◽  
Author(s):  
Tomohiro O. Sato ◽  
Takao M. Sato ◽  
Hideo Sagawa ◽  
Katsuyuki Noguchi ◽  
Naoko Saitoh ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Tropospheric Ozone ◽  
Vertical Profile ◽  
Reduction Rate ◽  
Estimation Method ◽  
Optimal Estimation ◽  
Sensitivity Study ◽  
Maximum Sensitivity ◽  
Radiative Transfer Model ◽  
Transfer Model

Abstract. We performed a feasibility study of constraining the vertical profile of the tropospheric ozone by using a synergetic retrieval method on multiple spectra, i.e., ultraviolet (UV), thermal infrared (TIR), and microwave (MW) ranges, measured from space. This work provides, for the first time, a quantitative evaluation of the retrieval sensitivity of the tropospheric ozone by adding the MW measurement to the UV and TIR measurements. Two observation points in East Asia (one in an urban area and one in an ocean area) and two observation times (one during summer and one during winter) were assumed. Geometry of line of sight was nadir down-looking for the UV and TIR measurements, and limb sounding for the MW measurement. The retrieval sensitivities of the ozone profiles in the upper troposphere (UT), middle troposphere (MT), and lowermost troposphere (LMT) were estimated using the degree of freedom for signal (DFS), the pressure of maximum sensitivity, reduction rate of error from the a priori error, and the averaging kernel matrix, derived based on the optimal estimation method. The measurement noise levels were assumed to be the same as those for currently available instruments. The weighting functions for the UV, TIR, and MW ranges were calculated using the SCIATRAN radiative transfer model, the Line-By-Line Radiative Transfer Model (LBLRTM), and the Advanced Model for Atmospheric Terahertz Radiation Analysis and Simulation (AMATERASU), respectively. The DFS value was increased by approximately 96, 23, and 30 % by adding the MW measurements to the combination of UV and TIR measurements in the UT, MT, and LMT regions, respectively. The MW measurement increased the DFS value of the LMT ozone; nevertheless, the MW measurement alone has no sensitivity to the LMT ozone. The pressure of maximum sensitivity value for the LMT ozone was also increased by adding the MW measurement. These findings indicate that better information on LMT ozone can be obtained by adding constraints on the UT and MT ozone from the MW measurement. The results of this study are applicable to the upcoming air-quality monitoring missions, APOLLO, GMAP-Asia, and uvSCOPE.

scholarly journals Vertical profile of tropospheric ozone derived from synergetic retrieval using three different wavelength ranges, UV, IR, and Microwave: sensitivity study for satellite observation

2017 ◽  
Author(s):  
Yasuko Kasai ◽  
Tomohiro O. Sato ◽  
Takao M. Sato ◽  
Hideo Sagawa ◽  
Katsuyuki Noguchi ◽  
...  
Keyword(s):  
Radiative Transfer ◽  
Vertical Profile ◽  
Estimation Method ◽  
Optimal Estimation ◽  
Satellite Observation ◽  
Sensitivity Study ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Retrieval Method ◽  
Advanced Model

Abstract. We performed a quantitative feasibility study of constraining the vertical profile of the amount of ozone in the troposphere by using a synergetic retrieval method on multiple spectra, i.e., ultraviolet (UV), thermal infrared (TIR) and microwave (MW) ranges, measured from space. Twenty atmospheric scenarios for East Asia in summer and winter seasons were assumed in this study. Geometry of line-of-sight was nadir down-looking for UV and TIR measurements, and limb-sounding for MW measurement. The sensitivities of retrieved ozone in the upper troposphere (UT), middle troposphere (MT) and lowermost troposphere (LMT) were estimated using values of the degree of freedom for signal (DFS), partial column error, and averaging kernel matrix, derived based on the optimal estimation method. The measurement noises were assumed at the same level as the currently available instruments. The weighting functions for the UV, TIR and MW ranges were calculated using the SCIATRAN radiative transfer model, the Line-By-Line Radiative Transfer Model, and the Advanced Model for Atmospheric Terahertz Radiation Analysis and Simulation, respectively. In the UT region, the DFS value was enhanced by about 200 % by adding the MW measurements to the combination of UV and TIR measurements. We found that the DFS value of the LMT ozone was increased by approximately 40 % by adding the MW measurements to the combination of UV and TIR measurements; nevertheless, the MW measurement alone has no sensitivity for the LMT ozone. Better information of the LMT ozone can be educed by adding constraints on the UT and MT ozone from the MW measurement. The results of this study will be implemented in the Japanese air-quality monitoring missions, APOLLO, GMAP-Asia and uvSCOPE.

scholarly journals BOREAS – a new MAX-DOAS profile retrieval algorithm for aerosols and trace gases

2018 ◽  
Vol 11 (12) ◽  
pp. 6833-6859 ◽  
Author(s):  
Tim Bösch ◽  
Vladimir Rozanov ◽  
Andreas Richter ◽  
Enno Peters ◽  
Alexei Rozanov ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Trace Gases ◽  
A Priori ◽  
Estimation Method ◽  
Optimal Estimation ◽  
Radiative Transfer Model ◽  
Retrieval Algorithm ◽  
Transfer Model ◽  
Night Time ◽  
Near Surface

Abstract. We present a new MAX-DOAS profiling algorithm for aerosols and trace gases, BOREAS, which utilizes an iterative solution method including Tikhonov regularization and the optimal estimation technique. The aerosol profile retrieval is based on a novel approach in which the absorption depth of O4 is directly used in order to retrieve extinction coefficient profiles instead of the commonly used perturbation theory method. The retrieval of trace gases is done with the frequently used optimal estimation method but significant improvements are presented on how to deal with wrongly weighted a priori constraints and for scenarios in which the a priori profile is inaccurate. Performance tests are separated into two parts. First, we address the general sensitivity of the retrieval to the example of synthetic data calculated with the radiative transfer model SCIATRAN. In the second part of the study, we demonstrate BOREAS profiling accuracy by validating the results with the help of ancillary measurements carried out during the CINDI-2 campaign in Cabauw, the Netherlands, in 2016. The synthetic sensitivity tests indicate that the regularization between measurement and a priori constraints is insufficient when knowledge of the true state of the atmosphere is poor. We demonstrate a priori pre-scaling and extensive regularization tests as a tool for the optimization of retrieved profiles. The comparison of retrieval results with in situ, ceilometer, NO2 lidar, sonde and long-path DOAS measurements during the CINDI-2 campaign always shows high correlations with coefficients greater than 0.75. The largest differences can be found in the morning hours, when the planetary boundary layer is not yet fully developed and the concentration of trace gases and aerosol, as a result of a low night-time boundary layer having formed, is focused in a shallow, near-surface layer.

scholarly journals Validating the MYSTIC three-dimensional radiative transfer model with observations from the complex topography of Arizona's Meteor Crater

2010 ◽  
Vol 10 (5) ◽  
pp. 13373-13405 ◽  
Author(s):  
B. Mayer ◽  
S. W. Hoch ◽  
C. D. Whiteman
Keyword(s):  
Monte Carlo ◽  
Radiative Transfer ◽  
Three Dimensional ◽  
Longwave Radiation ◽  
Horizontal Resolution ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Deep Basin ◽  
Near Surface ◽  
Radiation Fields

Abstract. The MYSTIC three-dimensional Monte-Carlo radiative transfer model has been extended to simulate solar and thermal irradiances with a rigorous consideration of topography. Forward as well as backward Monte Carlo simulations are possible for arbitrarily oriented surfaces and we demonstrate that the backward Monte Carlo technique is superior to the forward method for applications involving topography, by greatly reducing the computational demands. MYSTIC is used to simulate the short- and longwave radiation fields during a clear day and night in and around Arizona's Meteor Crater, a bowl-shaped, 165-m-deep basin with a diameter of 1200 m. The simulations are made over a 4 by 4 km domain using a 10-m horizontal resolution digital elevation model and meteorological input data collected during the METCRAX (Meteor Crater Experiment) field experiment in 2006. Irradiance (or radiative flux) measurements at multiple locations inside the crater are then used to evaluate the simulations. MYSTIC is shown to realistically model the complex interactions between topography and the radiative field, resolving the effects of terrain shading, terrain exposure, and longwave surface emissions. The effects of surface temperature variations and of temperature stratification within the crater atmosphere on the near-surface longwave irradiance are then evaluated with additional simulations.

scholarly journals Improved estimate of global dust radiative forcing using a coupled chemical transport-radiative transfer model

2013 ◽  
Vol 13 (1) ◽  
pp. 2415-2456 ◽  
Author(s):  
L. Zhang ◽  
Q. B. Li ◽  
Y. Gu ◽  
K. N. Liou ◽  
B. Meland
Keyword(s):  
Radiative Transfer ◽  
Vertical Profile ◽  
Radiative Forcing ◽  
Chemical Transport ◽  
Dust Particles ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Vertical Profiles ◽  
Dust Source ◽  
Source Regions

Abstract. Atmospheric mineral dust particles exert significant direct radiative forcings and are critical drivers of climate change. Here, we use the GEOS-Chem global three-dimensional chemical transport model (3-D CTM) coupled online with the Fu-Liou-Gu (FLG) radiative transfer model (RTM) to investigate the dust radiative forcing and heating rates based on different dust vertical profiles. The coupled calculations using a realistic dust vertical profile simulated by GEOS-Chem minimize the physical inconsistencies between 3-D CTM aerosol fields and the RTM. The use of GEOS-Chem simulated aerosol optical depth (AOD) vertical profiles as opposed to the FLG prescribed AOD vertical profiles leads to greater and more spatially heterogeneous changes in estimated radiative forcing and heating rate produced by dust. Both changes can be attributed to a different vertical structure between dust and non-dust source regions. Values of the dust AOD are much larger in the middle troposphere, though smaller at the surface when the GEOS-Chem simulated AOD vertical profile is used, which leads to a much stronger heating rate in the middle troposphere. Compared to FLG vertical profile, the use of GEOS-Chem vertical profile reduces the solar radiative forcing effect by about 0.2–0.25 W m−2 and the Infrared (IR) radiative forcing over the African and Asia dust source regions by about 0.1–0.2 W m−2. Differences in the solar radiative forcing at the surface between using the GEOS-Chem vertical profile and the FLG vertical profile are most significant over the Gobi desert with a value of about 1.1 W m−2. The radiative forcing effect of dust particles is more pronounced at the surface over the Sahara and Gobi deserts by using FLG vertical profile, while it is less significant over the downwind area of Eastern Asia.

scholarly journals The Successive-Order-of-Interaction Radiative Transfer Model. Part II: Model Performance and Applications

2006 ◽  
Vol 45 (10) ◽  
pp. 1403-1413 ◽  
Author(s):  
Christopher W. O’Dell ◽  
Andrew K. Heidinger ◽  
Thomas Greenwald ◽  
Peter Bauer ◽  
Ralf Bennartz
Keyword(s):  
Radiative Transfer ◽  
Data Assimilation ◽  
Weather Prediction ◽  
Model Performance ◽  
Optimal Estimation ◽  
Radiative Transfer Model ◽  
Transfer Model ◽  
Computationally Efficient ◽  
Wide Range ◽  
Infrared Wavelengths

Abstract Radiative transfer models for scattering atmospheres that are accurate yet computationally efficient are required for many applications, such as data assimilation in numerical weather prediction. The successive-order-of-interaction (SOI) model is shown to satisfy these demands under a wide range of conditions. In particular, the model has an accuracy typically much better than 1 K for most microwave and submillimeter cases in precipitating atmospheres. Its speed is found to be comparable to or faster than the commonly used though less accurate Eddington model. An adjoint has been written for the model, and so Jacobian sensitivities can be quickly calculated. In addition to a conventional error assessment, the correlation between errors in different microwave channels is also characterized. These factors combine to make the SOI model an appealing candidate for many demanding applications, including data assimilation and optimal estimation, from microwave to thermal infrared wavelengths.

scholarly journals Parameterizing radiative transfer to convert MAX-DOAS dSCDs into near-surface box-averaged mixing ratios

2013 ◽  
Vol 6 (6) ◽  
pp. 1521-1532 ◽  
Author(s):  
R. Sinreich ◽  
A. Merten ◽  
L. Molina ◽  
R. Volkamer
Keyword(s):  
Boundary Layer ◽  
Radiative Transfer ◽  
Mexico City ◽  
Vertical Gradient ◽  
Radiative Transfer Model ◽  
Optical Absorption Spectroscopy ◽  
Transfer Model ◽  
Model Calculations ◽  
Near Surface ◽  
Mixing Ratios

Abstract. We present a novel parameterization method to convert multi-axis differential optical absorption spectroscopy (MAX-DOAS) differential slant column densities (dSCDs) into near-surface box-averaged volume mixing ratios. The approach is applicable inside the planetary boundary layer under conditions with significant aerosol load, and builds on the increased sensitivity of MAX-DOAS near the instrument altitude. It parameterizes radiative transfer model calculations and significantly reduces the computational effort, while retrieving ~ 1 degree of freedom. The biggest benefit of this method is that the retrieval of an aerosol profile, which usually is necessary for deriving a trace gas concentration from MAX-DOAS dSCDs, is not needed. The method is applied to NO2 MAX-DOAS dSCDs recorded during the Mexico City Metropolitan Area 2006 (MCMA-2006) measurement campaign. The retrieved volume mixing ratios of two elevation angles (1° and 3°) are compared to volume mixing ratios measured by two long-path (LP)-DOAS instruments located at the same site. Measurements are found to agree well during times when vertical mixing is expected to be strong. However, inhomogeneities in the air mass above Mexico City can be detected by exploiting the different horizontal and vertical dimensions probed by the MAX-DOAS and LP-DOAS instruments. In particular, a vertical gradient in NO2 close to the ground can be observed in the afternoon, and is attributed to reduced mixing coupled with near-surface emission inside street canyons. The existence of a vertical gradient in the lower 250 m during parts of the day shows the general challenge of sampling the boundary layer in a representative way, and emphasizes the need of vertically resolved measurements.

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