Shipborne MAX-DOAS measurements for validation of TROPOMI NO2 products
Ping Wang, Ankie Piters, Jos van Geffen, Olaf Tuinder, Piet Stammes, and Stefan Kinne
Atmos. Meas. Tech., 13, 1413–1426, https://doi.org/10.5194/amt-13-1413-2020, 2020
The comparison of shipborne MAX-DOAS and TROPOMI NO2 products is important for the evaluation of the TROPOMI products. The ship cruises were mainly over remote oceans, thus we only measured background tropospheric NO2. Stratospheric NO2 was measured more accurately because there was almost no contamination from tropospheric NO2. We found that the TROPOMI stratospheric NO2 vertical column densities were slightly higher than the MAX-DOAS measurements.
Quality controls, bias, and seasonality of CO2 columns in the Boreal Forest with OCO-2, TCCON, and EM27/SUN measurements
Nicole Jacobs, William R. Simpson, Debra Wunch, Christopher W. O'Dell, Gregory B. Osterman, Frank Hase, Thomas Blumenstock, Qiansi Tu, Matthias Frey, Manvendra K. Dubey, Harrison A. Parker, Rigel Kivi, and Pauli Heikkinen
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2019-505,2020
Preprint under review for AMT (discussion: open, 0 comments)
The Boreal forest is the largest seasonally-varying biospheric carbon dioxide exchange region on Earth. This region is also undergoing amplified climate warming leading to concerns about the potential for altered regional carbon exchange. Satellite missions such as the orbiting carbon observer-2 (OCO-2) project can measure CO2 abundance over the Boreal forest, but need validation for assurance of accuracy. Therefore, we carried out ground-based validation of OCO-2 CO2 data at three locations.
Validation of tropospheric NO2 column measurements of GOME-2A and OMI using MAX-DOAS and direct sun network observations
Gaia Pinardi, Michel Van Roozendael, François Hendrick, Nicolas Theys, Nader Abuhassan, Alkiviadis Bais, Folkert Boersma, Alexander Cede, Jihyo Chong, Sebastian Donner, Theano Drosoglou, Udo Frieß, José Granville, Jay R. Herman, Henk Eskes, Robert Holla, Jari Hovila, Hitoshi Irie, Yugo Kanaya, Dimitris Karagkiozidis, Natalia Kouremeti, Jean-Christopher Lambert, Jianzhong Ma, Enno Peters, Ankie Piters, Oleg Postylyakov, Andreas Richter, Julia Remmers, Hisahiro Takashima, Martin Tiefengraber, Pieter Valks, Tim Vlemmix, Thomas Wagner, and Folkard Wittrock
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-76,2020
Preprint under review for AMT (discussion: open, 0 comments)
We validate several GOME-2 and OMI tropospheric NO2 products with 23 MAX-DOAS and 16 direct sun instruments distributed worldwide. We highlight large horizontal inhomogeneities at several sites affecting the validation results and we propose a method to quantify and correct for it. We show that the application of such correction reduces the satellite underestimation in almost all heterogeneous cases, but a negative bias remains over the MAX-DOAS + direct sun network ensemble for both satellites.
Testing the near-field Gaussian plume inversion flux quantification technique using unmanned aerial vehicle sampling
Adil Shah, Joseph R. Pitt, Hugo Ricketts, J. Brian Leen, Paul I. Williams, Khristopher Kabbabe, Martin W. Gallagher, and Grant Allen
Atmos. Meas. Tech., 13, 1467–1484, https://doi.org/10.5194/amt-13-1467-2020, 2020
Methane is a potent greenhouse gas, with large flux uncertainties from facility-scale sources, such as natural gas extraction infrastructure. A recently developed flux quantification method was successfully tested by flying an unmanned aerial vehicle (UAV) downwind of 22 controlled atmospheric methane releases. The UAVs were used to derive high-precision atmospheric methane measurements. The UAV methodology was successful in both detecting the release and providing a rough flux estimate.
InnFLUX – an open-source code for conventional and disjunct eddy covariance analysis of trace gas measurements: an urban test case
Marcus Striednig, Martin Graus, Tilmann D. Märk, and Thomas G. Karl
Atmos. Meas. Tech., 13, 1447–1465, https://doi.org/10.5194/amt-13-1447-2020, 2020
The current work summarizes a long-term effort to provide an open-source code for the analysis of turbulent fluctuations of trace gases in the atmosphere by eddy covariance and disjunct eddy covariance, with a special focus on reactive gases that participate in atmospheric chemistry. The performance of the code is successfully evaluated based on measurements of minute fluxes of non-methane volatile organic compounds into the urban atmosphere.
The 2018 fire season in North America as seen by TROPOMI: aerosol layer height intercomparisons and evaluation of model-derived plume heights
Debora Griffin, Christopher Sioris, Jack Chen, Nolan Dickson, Andrew Kovachik, Martin de Graaf, Swadhin Nanda, Pepijn Veefkind, Enrico Dammers, Chris A. McLinden, Paul Makar, and Ayodeji Akingunola
Atmos. Meas. Tech., 13, 1427–1445, https://doi.org/10.5194/amt-13-1427-2020, 2020
This study looks into validating the aerosol layer height product from the recently launched TROPOspheric Monitoring Instrument (TROPOMI) for forest fire plume through comparisons with two other satellite products, and interpreting differences due to the individual measurement techniques. These satellite observations are compared to predicted plume heights from Environment and Climate Change's air quality forecast model.
Shipborne MAX-DOAS measurements for validation of TROPOMI NO2 products
Ping Wang, Ankie Piters, Jos van Geffen, Olaf Tuinder, Piet Stammes, and Stefan Kinne
Atmos. Meas. Tech., 13, 1413–1426, https://doi.org/10.5194/amt-13-1413-2020, 2020
The comparison of shipborne MAX-DOAS and TROPOMI NO2 products is important for the evaluation of the TROPOMI products. The ship cruises were mainly over remote oceans, thus we only measured background tropospheric NO2. Stratospheric NO2 was measured more accurately because there was almost no contamination from tropospheric NO2. We found that the TROPOMI stratospheric NO2 vertical column densities were slightly higher than the MAX-DOAS measurements.
Quality controls, bias, and seasonality of CO2 columns in the Boreal Forest with OCO-2, TCCON, and EM27/SUN measurements
Nicole Jacobs, William R. Simpson, Debra Wunch, Christopher W. O'Dell, Gregory B. Osterman, Frank Hase, Thomas Blumenstock, Qiansi Tu, Matthias Frey, Manvendra K. Dubey, Harrison A. Parker, Rigel Kivi, and Pauli Heikkinen
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2019-505,2020
Preprint under review for AMT (discussion: open, 0 comments)
The Boreal forest is the largest seasonally-varying biospheric carbon dioxide exchange region on Earth. This region is also undergoing amplified climate warming leading to concerns about the potential for altered regional carbon exchange. Satellite missions such as the orbiting carbon observer-2 (OCO-2) project can measure CO2 abundance over the Boreal forest, but need validation for assurance of accuracy. Therefore, we carried out ground-based validation of OCO-2 CO2 data at three locations.
Evaluation of satellite-based aerosol datasets and the CAMS reanalysis over the ocean utilizing shipborne reference observations
Jonas Witthuhn, Anja Hünerbein, and Hartwig Deneke
Atmos. Meas. Tech., 13, 1387–1412, https://doi.org/10.5194/amt-13-1387-2020, 2020
Reliable reference measurements over ocean are essential for the evaluation and improvement of satellite- and model-based aerosol datasets. Here, a uniqe set of shipborne reference aerosol products obtained from Microtops sunphotometer and GUVis-3511 shadowband radiometer observations are compared to aerosol products from the MODIS and SEVIRI satellite sensors, and the CAMS reanalysis over the Atlantic Ocean. The present evaluation highlights the importance of an aerosol-type based analysis.
A Phase Separation Inlet for Droplets, Ice Residuals, and Interstitial Aerosols
Libby Koolik, Michael Roesch, Lesly J. Franco Deloya, Chuanyang Shen, A. Gannet Hallar, Ian B. McCubbin, and Daniel J. Cziczo
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2020-42,2020
Preprint under review for AMT (discussion: open, 0 comments)
The phaSe seParation Inlet for Droplets icE residuals and inteRstitial aerosols (SPIDER) combines an omni-directional inlet, a Large-Pumped Counterflow Virtual Impactor, a flow tube evaporation chamber, and a Pumped Counterflow Virtual Impactor to separate droplets, ice crystals, and interstitial aerosols for simultaneous sampling. This new inlet for studying mixed-phase clouds is described here, with laboratory verification tests and a deployment at a mountain-top research facility.
Evaluation of satellite-based aerosol datasets and the CAMS reanalysis over the ocean utilizing shipborne reference observations
Jonas Witthuhn, Anja Hünerbein, and Hartwig Deneke
Atmos. Meas. Tech., 13, 1387–1412, https://doi.org/10.5194/amt-13-1387-2020, 2020
Reliable reference measurements over ocean are essential for the evaluation and improvement of satellite- and model-based aerosol datasets. Here, a uniqe set of shipborne reference aerosol products obtained from Microtops sunphotometer and GUVis-3511 shadowband radiometer observations are compared to aerosol products from the MODIS and SEVIRI satellite sensors, and the CAMS reanalysis over the Atlantic Ocean. The present evaluation highlights the importance of an aerosol-type based analysis.
A Phase Separation Inlet for Droplets, Ice Residuals, and Interstitial Aerosols
Libby Koolik, Michael Roesch, Lesly J. Franco Deloya, Chuanyang Shen, A. Gannet Hallar, Ian B. McCubbin, and Daniel J. Cziczo
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-42,2020
Preprint under review for AMT (discussion: open, 0 comments)
The phaSe seParation Inlet for Droplets icE residuals and inteRstitial aerosols (SPIDER) combines an omni-directional inlet, a Large-Pumped Counterflow Virtual Impactor, a flow tube evaporation chamber, and a Pumped Counterflow Virtual Impactor to separate droplets, ice crystals, and interstitial aerosols for simultaneous sampling. This new inlet for studying mixed-phase clouds is described here, with laboratory verification tests and a deployment at a mountain-top research facility.
Retrieval of eddy dissipation rate from derived equivalent vertical gust included in Aircraft Meteorological Data Relay (AMDAR)
Soo-Hyun Kim, Hye-Yeong Chun, Jung-Hoon Kim, Robert D. Sharman, and Matt Strahan
Atmos. Meas. Tech., 13, 1373–1385, https://doi.org/10.5194/amt-13-1373-2020, 2020
We retrieve the eddy dissipation rate (EDR) from the derived equivalent vertical gust included in the Aircraft Meteorological Data Relay data for more reliable and consistent observations of aviation turbulence globally with the single preferred EDR metric. We convert the DEVG to the EDR using two methods (lognormal mapping scheme and best-fit curve between EDR and DEVG), and the DEVG-derived EDRs are evaluated against in situ EDR data reported by US-operated carriers.
Evaluation of UV Aerosol Retrievals from an Ozone Lidar
Shi Kuang, Bo Wang, Michael J. Newchurch, Paula Tucker, Edwin W. Eloranta, Joseph P. Garcia, Ilya Razenkov, John T. Sullivan, Timothy A. Berkoff, Guillaume Gronoff, Liqiao Lei, Christoph J. Senff, Andrew O. Langford, Thierry Leblanc, and Vijay Natraj
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2020-40,2020
Preprint under review for AMT (discussion: open, 0 comments)
Ozone lidar is a state-of-art remote sensing instrument to measure atmospheric ozone concentration with high spatio-temporal resolution. In this study, we show that an ozone lidar can also provide reliably aerosol measurements with high resolution by using the collocated data taken by the ozone lidar and an aerosol lidar. This means that ozone lidars are capable of providing simultaneous ozone and aerosol measurements.
Retrieval of eddy dissipation rate from derived equivalent vertical gust included in Aircraft Meteorological Data Relay (AMDAR)
Soo-Hyun Kim, Hye-Yeong Chun, Jung-Hoon Kim, Robert D. Sharman, and Matt Strahan
Atmos. Meas. Tech., 13, 1373–1385, https://doi.org/10.5194/amt-13-1373-2020, 2020
We retrieve the eddy dissipation rate (EDR) from the derived equivalent vertical gust included in the Aircraft Meteorological Data Relay data for more reliable and consistent observations of aviation turbulence globally with the single preferred EDR metric. We convert the DEVG to the EDR using two methods (lognormal mapping scheme and best-fit curve between EDR and DEVG), and the DEVG-derived EDRs are evaluated against in situ EDR data reported by US-operated carriers.
Evaluation of UV Aerosol Retrievals from an Ozone Lidar
Shi Kuang, Bo Wang, Michael J. Newchurch, Paula Tucker, Edwin W. Eloranta, Joseph P. Garcia, Ilya Razenkov, John T. Sullivan, Timothy A. Berkoff, Guillaume Gronoff, Liqiao Lei, Christoph J. Senff, Andrew O. Langford, Thierry Leblanc, and Vijay Natraj
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-40,2020
Preprint under review for AMT (discussion: open, 0 comments)
Ozone lidar is a state-of-art remote sensing instrument to measure atmospheric ozone concentration with high spatio-temporal resolution. In this study, we show that an ozone lidar can also provide reliably aerosol measurements with high resolution by using the collocated data taken by the ozone lidar and an aerosol lidar. This means that ozone lidars are capable of providing simultaneous ozone and aerosol measurements.
Simultaneous leaf-level measurement of trace gas emissions and photosynthesis with a portable photosynthesis system
Mj Riches, Daniel Lee, and Delphine K. Farmer
Atmos. Meas. Tech. Discuss., https://doi.org/10.5194/amt-2020-45,2020
Preprint under review for AMT (discussion: open, 0 comments)
This manuscript presents a thorough characterization of a leaf emission sampling technique, coupling a portable photosynthesis system with different trace gas analyzers. We further provide several case studies using both online and offline gas analyzers to measure different types of leaf emissions. We further highlight both the capabilities and pitfalls of this method.
Simultaneous leaf-level measurement of trace gas emissions and photosynthesis with a portable photosynthesis system
Mj Riches, Daniel Lee, and Delphine K. Farmer
Atmos. Meas. Tech. Discuss., https//doi.org/10.5194/amt-2020-45,2020
Preprint under review for AMT (discussion: open, 0 comments)
This manuscript presents a thorough characterization of a leaf emission sampling technique, coupling a portable photosynthesis system with different trace gas analyzers. We further provide several case studies using both online and offline gas analyzers to measure different types of leaf emissions. We further highlight both the capabilities and pitfalls of this method.
The limited-angle projection data of an object, in some practical applications of computed tomography (CT), are obtained due to the restriction of scanning condition.
In these situations, since the projection data are incomplete, some limited-angle artifacts will be presented near the edges of reconstructed image using some classical reconstruction algorithms, such as filtered backprojection (FBP).
The reconstructed image can be fine approximated by sparse coefficients under a proper wavelet tight frame, and the quality of reconstructed image can be improved by an available prior image. To deal with limited-angle CT reconstruction problem, we propose a minimization model that is based on wavelet tight frame and a prior image, and perform this minimization problem efficiently
by iteratively minimizing separately. Moreover, we show that each bounded sequence, which is generated by our method, converges to a critical or a stationary point. The experimental results indicate that our algorithm can efficiently suppress artifacts and noise and preserve the edges of reconstructed image, what's more, the introduced prior image will not miss the important information that is not included in the prior image.
Restoration of images contaminated by multiplicative noise (also
known as speckle noise) is a key issue in coherent image
processing. Notice that images under consideration are often highly compressible in certain suitably chosen
transform domains. By exploring this intrinsic feature embedded in images, this paper introduces a variational restoration model
for multiplicative noise reduction that consists of a term
reflecting the observed image and multiplicative noise, a quadratic
term measuring the closeness of the underlying image in a transform
domain to a sparse vector, and a sparse regularizer for removing
multiplicative noise. Being different from popular existing models
which focus on pursuing convexity, the proposed sparsity-aware model
may be nonconvex depending on the conditions of the parameters of
the model for achieving the optimal denoising performance. An algorithm for finding a critical point of the objective function of the model is developed based on coupled fixed-point equations expressed in terms of the proximity operator of functions that appear in the objective function. Convergence analysis of the algorithm is provided.
Experimental results are shown to demonstrate that the proposed iterative algorithm is sensitive to some initializations for obtaining the best restoration results. We observe that the proposed method with SAR-BM3D filtering images as initial estimates can remarkably outperform several state-of-art methods in terms of the
quality of the restored images.
