Kumar R, Mitchell DA, Steinhoff DF, Saide P, Kosovic B, Downey N, Blewitt D, Delle Monache L. Evaluating the Mobile Flux Plane (MFP) Method to Estimate Methane Emissions Using Large Eddy Simulations (LES). Journal of Geophysical Research: Atmospheres [Internet]. 2021;126 (5) :e2020JD032663. Publisher's VersionAbstract
Abstract This study evaluates the efficacy of the mobile flux plane (MFP) method to derive methane emissions from oil and gas production fields using a first-of-its-kind high-resolution methane concentration data set. Transport and dispersion of methane emissions from seven hypothetical well pads generated with an oil field emission simulator is simulated every second at 10 m resolution using the Weather Research and Forecasting (WRF) model in large eddy simulation mode. The time varying WRF-generated methane concentration data set is sampled by a simulated MFP system downwind of the seven well pads at five sampling distances of 50, 75, 100, 125, and 150 m. Several key findings highlight the significant variability in MFP emission rate estimates induced by atmospheric turbulence and variable source emission rates. Natural atmospheric turbulence alone was found to generate significant variability (33%–75%) in the MFP emission estimates with constant emission rates at the source location. It was also found that turbulent wind speed fluctuations over the duration of a transect can also affect MFP estimates up to about ±50% through convergence (divergence) that increases (decreases) methane concentrations, and by its effect on the assumption of steady winds over the duration of the transect. It was further found that the MFP method typically estimated about 19%–33% and 51%–75% of known site emission rates using the trapezoidal and Gaussian fit integration methods, respectively. Thus, methane concentrations would need to be measured to a much higher elevation to generate robust and accurate methane emission rate estimates.
Redemann J, Wood R, Zuidema P, Doherty SJ, Luna B, LeBlanc SE, Diamond MS, Shinozuka Y, Chang IY, Ueyama R, et al. An overview of the ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS) project: aerosol–cloud–radiation interactions in the southeast Atlantic basin. Atmospheric Chemistry and Physics [Internet]. 2021;21 (3) :1507–1563. Publisher's Version
Shinozuka Y, Saide PE, Ferrada GA, Burton SP, Ferrare R, Doherty SJ, Gordon H, Longo K, Mallet M, Feng Y, et al. Modeling the smoky troposphere of the southeast Atlantic: a comparison to ORACLES airborne observations from September of 2016. Atmospheric Chemistry and Physics [Internet]. 2020;20 (19) :11491–11526. Publisher's Version
Saide PE, Gao M, Lu Z, Goldberg DL, Streets DG, Woo J-H, Beyersdorf A, Corr CA, Thornhill KL, Anderson B, et al. Understanding and improving model representation of aerosol optical properties for a Chinese haze event measured during KORUS-AQ. Atmospheric Chemistry and Physics [Internet]. 2020;20 (11) :6455–6478. Publisher's Version
Choi S, Lamsal LN, Follette-Cook M, Joiner J, Krotkov NA, Swartz WH, Pickering KE, Loughner CP, Appel W, Pfister G, et al. Assessment of NO2 observations during DISCOVER-AQ and KORUS-AQ field campaigns. Atmospheric Measurement Techniques [Internet]. 2020;13 (5) :2523–2546. Publisher's Version
Lee S, Song CH, Han KM, Henze DK, Lee K, Yu J, Woo J-H, Jung J, Choi Y, Saide PE, et al. The impacts of uncertainties in emissions on aerosol data assimilation and short-term PM2.5 predictions in CMAQ v5.2.1 over East Asia. Geoscientific Model Development Discussions [Internet]. 2020;2020 :1–31. Publisher's Version
Choi M, Lim H, Kim J, Lee S, Eck TF, Holben BN, Garay MJ, Hyer EJ, Saide PE, Liu H. Validation, comparison, and integration of GOCI, AHI, MODIS, MISR, and VIIRS aerosol optical depth over East Asia during the 2016 KORUS-AQ campaign. Atmospheric Measurement Techniques [Internet]. 2019;12 (8) :4619–4641. Publisher's Version
Mallet M, Nabat P, Zuidema P, Redemann J, Sayer AM, Stengel M, Schmidt S, Cochrane S, Burton S, Ferrare R, et al. Simulation of the transport, vertical distribution, optical properties and radiative impact of smoke aerosols with the ALADIN regional climate model during the ORACLES-2016 and LASIC experiments. Atmospheric Chemistry and Physics [Internet]. 2019;19 (7) :4963–4990. Publisher's Version
Kumar R, Delle Monache L, Bresch J, Saide PE, Tang Y, Liu Z, da Silva AM, Alessandrini S, Pfister G, Edwards D, et al. Toward Improving Short-Term Predictions of Fine Particulate Matter Over the United States Via Assimilation of Satellite Aerosol Optical Depth Retrievals. Journal of Geophysical Research: Atmospheres [Internet]. 2019;124 (5) :2753-2773. Publisher's VersionAbstract
Abstract This study develops a new approach to improve simulations of the particulate matter of aerodynamic diameter smaller than 2.5 μm (PM2.5) in the Community Multiscale Air Quality (CMAQ) model via assimilation of Moderate Resolution Imaging Spectroradiometer (MODIS) aerosol optical depth (AOD) retrievals using the Gridpoint Statistical Interpolation (GSI) system. In contrast to previous studies that only consider errors due to transport, our computation of the background error covariance matrix incorporates uncertainties in anthropogenic emissions. To understand the impact of this approach, three experiments (one background and two assimilations) are performed over the contiguous United States (CONUS) from 15 July to 14 August 2014. The background CMAQ experiment significantly underestimates both the MODIS AOD and surface PM2.5 levels. MODIS AOD assimilation pushes both the CMAQ AOD and surface PM2.5 distributions toward the observed distributions, but CMAQ still underestimates the observations. Averaged over CONUS, the two assimilation experiments with and without including the anthropogenic emission uncertainties improve the correlation coefficient between the model and independent observations of PM2.5 by  67% and  48%, respectively, and reduces the mean bias by  38% and  10%, respectively. The assimilation improves the model performance everywhere over CONUS, except the New York and Wisconsin, where CMAQ overestimates the observed PM2.5 during nighttime after assimilation likely because of overcorrection of aerosol mass concentrations by the AOD assimilation. Future work should incorporate uncertainties in other processes (biomass burning and biogenic emissions, deposition, chemistry, transport, and boundary conditions) to further enhance the value of assimilating spaceborne AOD retrievals.
Goldberg DL, Saide PE, Lamsal LN, de Foy B, Lu Z, Woo J-H, Kim Y, Kim J, Gao M, Carmichael G, et al. A top-down assessment using OMI NO2 suggests an underestimate in the NOx emissions inventory in Seoul, South Korea, during KORUS-AQ. Atmospheric Chemistry and Physics [Internet]. 2019;19 (3) :1801–1818. Publisher's Version
Abdi-Oskouei M, Pfister G, Flocke F, Sobhani N, Saide P, Fried A, Richter D, Weibring P, Walega J, Carmichael G. Impacts of physical parameterization on prediction of ethane concentrations for oil and gas emissions in WRF-Chem. Atmospheric Chemistry and Physics [Internet]. 2018;18 (23) :16863–16883. Publisher's Version
Mallet M, Nabat P, Zuidema P, Redemann J, Sayer AM, Stengel M, Schmidt S, Cochrane S, Burton S, Ferrare R, et al. Simulation of the transport, vertical distribution, optical properties and radiative impact of smoke aerosols with the ALADIN regional climate model during the ORACLES-2016 and LASIC experiments. Atmospheric Chemistry and Physics Discussions [Internet]. 2018;2018 :1–49. Publisher's Version
Lennartson EM, WANG J, Gu J, Castro Garcia L, Ge C, Gao M, Choi M, Saide PE, Carmichael GR, Kim J, et al. Diurnal variation of aerosol optical depth and PM2.5 in South Korea: a synthesis from AERONET, satellite (GOCI), KORUS-AQ observation, and the WRF-Chem model. Atmospheric Chemistry and Physics [Internet]. 2018;18 (20) :15125–15144. Publisher's Version
Saide PE, Steinhoff DF, Kosovic B, Weil J, Downey N, Blewitt D, Hanna SR, Delle Monache L. Evaluating Methods To Estimate Methane Emissions from Oil and Gas Production Facilities Using LES Simulations. Environmental Science & Technology [Internet]. 2018;52 (19) :11206-11214. Publisher's Version
Diamond MS, Dobracki A, Freitag S, Small Griswold JD, Heikkila A, Howell SG, Kacarab ME, Podolske JR, Saide PE, Wood R. Time-dependent entrainment of smoke presents an observational challenge for assessing aerosol–cloud interactions over the southeast Atlantic Ocean. Atmospheric Chemistry and Physics [Internet]. 2018;18 (19) :14623–14636. Publisher's Version
Burton SP, Hostetler CA, Cook AL, Hair JW, Seaman ST, Scola S, Harper DB, Smith JA, Fenn MA, Ferrare RA, et al. Calibration of a high spectral resolution lidar using a Michelson interferometer, with data examples from ORACLES. Appl. Opt. [Internet]. 2018;57 (21) :6061–6075. Publisher's VersionAbstract
The NASA Langley airborne second-generation High Spectral Resolution Lidar (HSRL-2) uses a density-tuned field-widened Michelson interferometer to implement the HSRL technique at 355&\#x00A0;nm. The Michelson interferometer optically separates the received backscattered light between two channels, one of which is dominated by molecular backscattering, while the other contains most of the light backscattered by particles. This interferometer achieves high and stable contrast ratio, defined as the ratio of particulate backscatter signal received by the two channels. We show that a high and stable contrast ratio is critical for precise and accurate backscatter and extinction retrievals. Here, we present retrieval equations that take into account the incomplete separation of particulate and molecular backscatter in the measurement channels. We also show how the accuracy of the contrast ratio assessment propagates to error in the optical properties. For both backscattering and extinction, larger errors are produced by underestimates of the contrast ratio (compared to overestimates), more extreme aerosol loading, and&\#x2014;most critically&\#x2014;smaller true contrast ratios. We show example results from HSRL-2 aboard the NASA ER-2 aircraft from the 2016 ORACLES field campaign in the southeast Atlantic, off the coast of Africa, during the biomass burning season. We include a case study where smoke aerosol in two adjacent altitude layers showed opposite differences in extinction- and backscatter-related &\#x00C5;ngstr&\#x00F6;m exponents and a reversal of the lidar ratio spectral dependence, signatures which are shown to be consistent with a relatively modest difference in smoke particle size.
Gao M, Carmichael GR, Wang Y, Saide PE, Liu Z, Xin J, Shan Y, Wang Z. Chemical and Meteorological Feedbacks in the Formation of Intense Haze Events. In: Bouarar I, Wang X, Brasseur GP Air Pollution in Eastern Asia: An Integrated Perspective. Cham: Springer International Publishing ; 2017. pp. 437–452. Publisher's VersionAbstract
Intense haze events in China provide ideal opportunities to study meteorological and chemical feedbacks due to extremely high aerosol loadings. In this chapter, an online coupled meteorology-chemistry model, WRF-Chem, is applied to simulate impacts of aerosol feedbacks on meteorology and air quality during the January 2010 haze event over the North China Plain (NCP). The results show that the model reasonably reproduces well most meteorological, chemical and optical variables. Aerosols during this haze event can reduce surface downward shortwave radiation by 25.7% and planetary boundary layer height by 14.9%. Due to aerosol feedbacks, PM2.5 concentrations in urban Beijing increase by 11.2% at 14:00. The severe haze also enhances cloud droplet number concentrations, which can further affect cloud chemistry. These results indicate that aerosol feedbacks in the NCP, especially in urban regions, are important and should be considered when develop air pollution control and climate mitigation strategies.
Gao M, Saide PE, Xin J, Wang Y, Liu Z, Wang Y, Wang Z, Pagowski M, Guttikunda SK, Carmichael GR. Estimates of Health Impacts and Radiative Forcing in Winter Haze in Eastern China through Constraints of Surface PM2.5 Predictions. Environmental Science & Technology [Internet]. 2017;51 (4) :2178-2185. Publisher's Version
Saide PE, Thompson G, Eidhammer T, da Silva AM, Pierce RB, Carmichael GR. Assessment of biomass burning smoke influence on environmental conditions for multiyear tornado outbreaks by combining aerosol-aware microphysics and fire emission constraints. Journal of Geophysical Research: Atmospheres [Internet]. 2016;121 (17) :10,294–10,311. Publisher's Version
Gao M, Carmichael GR, Saide PE, Lu Z, Yu M, Streets DG, Wang Z. Response of winter fine particulate matter concentrations to emission and meteorology changes in North China. Atmospheric Chemistry and Physics [Internet]. 2016;16 (18) :11837–11851. Publisher's Version