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Response of Hurricane Harvey's rainfall to anthropogenic aerosols: A sensitivity study based on spectral bin microphysics with simulated aerosolsSouri, Amir H.Choi, YunsooKodros, John K.Jung, JiaShpund, JacobPierce, Jeffrey R.Lynn, Barry H.Khain, AlexanderChance, KellyDOI: info:10.1016/j.atmosres.2020.104965v. 242104965
Souri, Amir H., Choi, Yunsoo, Kodros, John K., Jung, Jia, Shpund, Jacob, Pierce, Jeffrey R., Lynn, Barry H., Khain, Alexander, and Chance, Kelly. 2020. "Response of Hurricane Harvey's rainfall to anthropogenic aerosols: A sensitivity study based on spectral bin microphysics with simulated aerosols." Atmospheric Research 242:104965. https://doi.org/10.1016/j.atmosres.2020.104965
ID: 157461
Type: article
Authors: Souri, Amir H.; Choi, Yunsoo; Kodros, John K.; Jung, Jia; Shpund, Jacob; Pierce, Jeffrey R.; Lynn, Barry H.; Khain, Alexander; Chance, Kelly
Abstract: A number of human-induced elements contribute to influencing the intensity of tropical cyclones and prolonging their lifetime. Not only do ocean heat content, large-scale weather patterns, and surface properties affect the amount of release of energy, but the modulation from aerosol particles on cloud properties is also present. With Hurricane Harvey (2017) fairly isolated over Texas, there was a unique opportunity to study the indirect impact of aerosols on the amount of record-breaking rainfall over the greater Houston area. Due to the non-linear processes involved in clouds microstructure, aerosol properties and the variability associated with the atmospheric environment, the quantification of the response of storms to aerosols is complex. To this end, we first reproduce Harvey using the Weather Research and Forecasting (WRF) model coupled with a 3D-var assimilation framework that incorporates satellites, radio occultation, dropsondes, and surface measurements. We then study the aerosol indirect impacts using spectral bin microphysics in conjunction with aerosol properties simulated from the Goddard Earth Observing System (GEOS)-Chem TwO-Moment Aerosol Sectional (TOMAS) model leveraging online aerosol microphysics with anthropogenic emissions (SP) and without ones (SC). In the vicinity of Harvey's landfall, the number concentration of cloud condensation nuclei at 1% supersaturation using the anthropogenic emissions is found to be one order of magnitude (855 cm-3) larger than those simulated with only natural emissions (83 cm-3). We observed that a narrow plume of anthropogenic aerosols from western Texas was transported over the area at the moment when deep convection initiated, accelerating updrafts through releasing more latent heat, which in turn, resulted in an average enhancement of precipitation by 25 mm (~ 8%) over the greater Houston area. We observed a second peak at the right tail of the distribution of differences between experiments, which is an indication of the presence of more extreme rainfall over the area. As such, studies on the impact of aerosol emissions controls on exacerbating severe weather should be more encouraged.
An inversion of NOx and non-methane volatile organic compound (NMVOC) emissions using satellite observations during the KORUS-AQ campaign and implications for surface ozone over East AsiaSouri, Amir H.Nowlan, Caroline R.González Abad, GonzaloZhu, LeiBlake, Donald R.Fried, AlanWeinheimer, Andrew J.Wisthaler, ArminWoo, Jung-HunZhang, QiangMiller, Christopher E. ChanLiu, XiongChance, KellyDOI: info:10.5194/acp-20-9837-2020v. 209837–9854
Souri, Amir H., Nowlan, Caroline R., González Abad, Gonzalo, Zhu, Lei, Blake, Donald R., Fried, Alan, Weinheimer, Andrew J., Wisthaler, Armin, Woo, Jung-Hun, Zhang, Qiang, Miller, Christopher E. Chan, Liu, Xiong, and Chance, Kelly. 2020. "An inversion of NOx and non-methane volatile organic compound (NMVOC) emissions using satellite observations during the KORUS-AQ campaign and implications for surface ozone over East Asia." Atmospheric Chemistry & Physics 20:9837– 9854. https://doi.org/10.5194/acp-20-9837-2020
ID: 158080
Type: article
Authors: Souri, Amir H.; Nowlan, Caroline R.; González Abad, Gonzalo; Zhu, Lei; Blake, Donald R.; Fried, Alan; Weinheimer, Andrew J.; Wisthaler, Armin; Woo, Jung-Hun; Zhang, Qiang; Miller, Christopher E. Chan; Liu, Xiong; Chance, Kelly
Abstract: The absence of up-to-date emissions has been a major impediment to accurately simulating aspects of atmospheric chemistry and to precisely quantifying the impact of changes in emissions on air pollution. Hence, a nonlinear joint analytical inversion (Gauss-Newton method) of both volatile organic compounds (VOCs) and nitrogen oxide (NOx) emissions is made by exploiting the Smithsonian Astrophysical Observatory (SAO) Ozone Mapping and Profiler Suite Nadir Mapper (OMPS-NM) formaldehyde (HCHO) and the National Aeronautics and Space Administration (NASA) Ozone Monitoring Instrument (OMI) tropospheric nitrogen dioxide (NO2) columns during the Korea-United States Air Quality (KORUS-AQ) campaign over East Asia in May-June 2016. Effects of the chemical feedback of NOx and VOCs on both NO2 and HCHO are implicitly included by iteratively optimizing the inversion. Emission uncertainties are greatly narrowed (averaging kernels > 0.8, which is the mathematical presentation of the partition of information gained from the satellite observations with respect to the prior knowledge) over medium- to high-emitting areas such as cities and dense vegetation. The prior amount of total NOx emissions is mainly dictated by values reported in the MIX-Asia 2010 inventory. After the inversion we conclude that there is a decline in emissions (before, after, change) for China (87.94±44.09 Gg d-1, 68.00±15.94 Gg d-1, -23 %), North China Plain (NCP) (27.96±13.49 Gg d-1, 19.05±2.50 Gg d-1, -32 %), Pearl River Delta (PRD) (4.23±1.78 Gg d-1, 2.70±0.32 Gg d-1, -36 %), Yangtze River Delta (YRD) (9.84±4.68 Gg d-1, 5.77±0.51 Gg d-1, -41 %), Taiwan (1.26±0.57 Gg d-1, 0.97±0.33 Gg d-1, -23 %), and Malaysia (2.89±2.77 Gg d-1, 2.25±1.34 Gg d-1, -22 %), all of which have effectively implemented various stringent regulations. In contrast, South Korea (2.71±1.34 Gg d-1, 2.95±0.58 Gg d-1, +9 %) and Japan (3.53±1.71 Gg d-1, 3.96±1.04 Gg d-1, +12 %) are experiencing an increase in NOx emissions, potentially due to an increased number of diesel vehicles and new thermal power plants. We revisit the well-documented positive bias (by a factor of 2 to 3) of MEGAN v2.1 (Model of Emissions of Gases and Aerosols from Nature) in terms of biogenic VOC emissions in the tropics. The inversion, however, suggests a larger growth of VOCs (mainly anthropogenic) over NCP (25 %) than previously reported (6 %) relative to 2010. The spatial variation in both the magnitude and sign of NOx and VOC emissions results in nonlinear responses of ozone production and loss. Due to a simultaneous decrease and increase in NOx/VOC over NCP and YRD, we observe a ∼53 % reduction in the ratio of the chemical loss of NOx (LNOx) to the chemical loss of ROx (RO2+HO2) over the surface transitioning toward NOx-sensitive regimes, which in turn reduces and increases the afternoon chemical loss and production of ozone through NO2+OH (-0.42 ppbv h-1)/HO2 (and RO2)+NO (+0.31 ppbv h-1). Conversely, a combined decrease in NOx and VOC emissions in Taiwan, Malaysia, and southern China suppresses the formation of ozone. Simulations using the updated emissions indicate increases in maximum daily 8 h average (MDA8) surface ozone over China (0.62 ppbv), NCP (4.56 ppbv), and YRD (5.25 ppbv), suggesting that emission control strategies on VOCs should be prioritized to curb ozone production rates in these regions. Taiwan, Malaysia, and PRD stand out as regions undergoing lower MDA8 ozone levels resulting from the NOx reductions occurring predominantly in NOx-sensitive regimes.
Corrigendum to 'Revisiting the effectiveness of HCHO/NO2 ratios for inferring ozone sensitivity to its precursors using high resolution airborne remote sensing observations in a high ozone episode during the KORUS-AQ campaign' [Atmos. Environ. 224 117341]Souri, Amir H.Nowlan, Caroline R.Wolfe, Glenn M.Lamsal, Lok N.Chan Miller, Christopher E.González Abad, GonzaloJanz, Scott J.Fried, AlanBlake, Donald R.Weinheimer, Andrew J.Diskin, Glenn S.Liu, XiongChance, KellyDOI: info:10.1016/j.atmosenv.2020.117792v. 240117792
Souri, Amir H., Nowlan, Caroline R., Wolfe, Glenn M., Lamsal, Lok N., Chan Miller, Christopher E., González Abad, Gonzalo, Janz, Scott J., Fried, Alan, Blake, Donald R., Weinheimer, Andrew J., Diskin, Glenn S., Liu, Xiong, and Chance, Kelly. 2020. "Corrigendum to "Revisiting the effectiveness of HCHO/NO2 ratios for inferring ozone sensitivity to its precursors using high resolution airborne remote sensing observations in a high ozone episode during the KORUS-AQ campaign" [Atmos. Environ. 224 117341]." Atmospheric Environment 240:117792. https://doi.org/10.1016/j.atmosenv.2020.117792
ID: 157460
Type: article
Authors: Souri, Amir H.; Nowlan, Caroline R.; Wolfe, Glenn M.; Lamsal, Lok N.; Chan Miller, Christopher E.; González Abad, Gonzalo; Janz, Scott J.; Fried, Alan; Blake, Donald R.; Weinheimer, Andrew J.; Diskin, Glenn S.; Liu, Xiong; Chance, Kelly
Abstract: The authors regret both Fig. S2 and Fig. S3 were inadvertently used a wrong day (06/10 instead of 06/09 due to a difference in the UTC vs local times) for plotting the NASA's LaRC box model output. The new figure shows that both F0AM and LaRC models are in a strong degree of agreement (<10%) suggesting that the non-linear ozone chemistry over Seoul can be reasonably represented by both models. This correction does not impact the conclusion drawn from this study. We thank James H. Crawford for pointing us at the bug.
Quantifying the Impact of Excess Moisture From Transpiration From Crops on an Extreme Heat Wave Event in the Midwestern U.S.: A Top-Down Constraint From Moderate Resolution Imaging Spectroradiometer Water Vapor RetrievalSouri, Amir H.Wang, HuiqunGonzález Abad, GonzaloLiu, XiongChance, KellyDOI: info:10.1029/2019JD031941v. 125e31941
Souri, Amir H., Wang, Huiqun, González Abad, Gonzalo, Liu, Xiong, and Chance, Kelly. 2020. "Quantifying the Impact of Excess Moisture From Transpiration From Crops on an Extreme Heat Wave Event in the Midwestern U.S.: A Top-Down Constraint From Moderate Resolution Imaging Spectroradiometer Water Vapor Retrieval." Journal of Geophysical Research (Atmospheres) 125:e31941. https://doi.org/10.1029/2019JD031941
ID: 157311
Type: article
Authors: Souri, Amir H.; Wang, Huiqun; González Abad, Gonzalo; Liu, Xiong; Chance, Kelly
Abstract: The primary focus of this study is to understand the contribution from excess moisture from crop transpiration to the severity of a heat wave episode that hit the Midwestern U.S. from 16 to 20 July 2011. To elucidate this, we first provide an optimal estimate of the transpiration water vapor flux using satellite total column water vapor retrievals whose accuracy and precision are characterized using independent observations. The posterior transpiration flux is estimated using a local ensemble transform Kalman filter that employs a mesoscale weather model as the forward model. The new estimation suggests that the prior values of transpiration flux from crops are biased high by 15%. We further use the constrained flux to examine the sensitivity of meteorology to the contributions from crops. Over the agricultural areas during daytime, elevated moisture (up to 40%) from crops not only increases humidity (thus the heat index) but also provides a positive radiative forcing by increasing downward longwave radiation (13 ± 4 W m-2) that results in even higher surface air temperature (+0.4 °C). Consequently, we find that the elevated moisture generally provides positive feedback to aggravate the heat wave, with daytime enhancements of heat index by as large as 3.3 ± 0.8 °C. Due to a strong diurnal cycle in the transpiration, the feedback tends to be stronger in the afternoon (up to 5 °C) and weaker at night. Results offer a potential basis for designing mitigation strategies for the effect of transpiration from agriculture in the future, in addition to improving the estimation of canopy transpiration.
Revisiting the effectiveness of HCHO/NO2 ratios for inferring ozone sensitivity to its precursors using high resolution airborne remote sensing observations in a high ozone episode during the KORUS-AQ campaignSouri, Amir HosseinNowlan, Caroline R.Wolfe, Glenn M.Lamsal, Lok N.Chan Miller, Christopher E.Abad, Gonzalo GonzálezJanz, Scott J.Fried, AlanBlake, Donald R.Weinheimer, Andrew J.Diskin, Glenn S.Liu, XiongChance, KellyDOI: info:10.1016/j.atmosenv.2020.117341v. 224117341
Souri, Amir Hossein, Nowlan, Caroline R., Wolfe, Glenn M., Lamsal, Lok N., Chan Miller, Christopher E., Abad, Gonzalo González, Janz, Scott J., Fried, Alan, Blake, Donald R., Weinheimer, Andrew J., Diskin, Glenn S., Liu, Xiong, and Chance, Kelly. 2020. "Revisiting the effectiveness of HCHO/NO2 ratios for inferring ozone sensitivity to its precursors using high resolution airborne remote sensing observations in a high ozone episode during the KORUS-AQ campaign." Atmospheric Environment 224:117341. https://doi.org/10.1016/j.atmosenv.2020.117341
ID: 156335
Type: article
Authors: Souri, Amir Hossein; Nowlan, Caroline R.; Wolfe, Glenn M.; Lamsal, Lok N.; Chan Miller, Christopher E.; Abad, Gonzalo González; Janz, Scott J.; Fried, Alan; Blake, Donald R.; Weinheimer, Andrew J.; Diskin, Glenn S.; Liu, Xiong; Chance, Kelly
Abstract: The nonlinear chemical processes involved in ozone production (P(O3)) have necessitated using proxy indicators to convey information about the primary dependence of P(O3) on volatile organic compounds (VOCs) or nitrogen oxides (NOx). In particular, the ratio of remotely sensed columns of formaldehyde (HCHO) to nitrogen dioxide (NO2) has been widely used for studying O3 sensitivity. Previous studies found that the errors in retrievals and the incoherent relationship between the column and the near-surface concentrations are a barrier in applying the ratio in a robust way. In addition to these obstacles, we provide calculational- observational evidence, using an ensemble of 0-D photochemical box models constrained by DC-8 aircraft measurements on an ozone event during the Korea-United States Air Quality (KORUS-AQ) campaign over Seoul, to demonstrate the chemical feedback of NO2 on the formation of HCHO is a controlling factor for the transition line between NOx-sensitive and NOx-saturated regimes. A fixed value (~2.7) of the ratio of the chemical loss of NOx (LNOx) to the chemical loss of HO2+RO2 (LROx) perceptibly differentiates the regimes. Following this value, data points with a ratio of HCHO/NO2 less than 1 can be safely classified as NOx-saturated regime, whereas points with ratios between 1 and 4 fall into one or the other regime. We attribute this mainly to the HCHO-NO2 chemical relationship causing the transition line to occur at larger (smaller) HCHO/NO2 ratios in VOC-rich (VOC-poor) environments. We then redefine the transition line to LNOx/LROx~2.7 that accounts for the HCHO-NO2 chemical relationship leading to HCHO = 3.7 × (NO2 - 1.14 × 1016 molec.cm-2). Although the revised formula is locally calibrated (i.e., requires for readjustment for other regions), its mathematical format removes the need for having a wide range of thresholds used in HCHO/NO2 ratios that is a result of the chemical feedback. Therefore, to be able to properly take the chemical feedback into consideration, the use of HCHO = a × (NO2 - b) formula should be preferred to the ratio in future works. We then use the Geostationary Trace gas and Aerosol Sensor Optimization (GeoTASO) airborne instrument to study O3 sensitivity in Seoul. The unprecedented spatial (250 × 250 m2) and temporal (~every 2 h) resolutions of HCHO and NO2 observations form the sensor enhance our understanding of P(O3) in Seoul; rather than providing a crude label for the entire city, more in-depth variabilities in chemical regimes are observed that should be able to inform mitigation strategies correspondingly.
Five decades observing Earth's atmospheric trace gases using ultraviolet and visible backscatter solar radiation from spaceGonzalez Abad, GonzaloSouri, Amir HosseinBak, JuseonChance, KellyFlynn, Lawrence E.Krotkov, Nickolay A.Lamsal, LokLi, CanLiu, XiongChan Miller, ChristopherNowlan, Caroline R.Suleiman, RaidWang, HuiqunDOI: info:10.1016/j.jqsrt.2019.04.030v. 238106478
Gonzalez Abad, Gonzalo, Souri, Amir Hossein, Bak, Juseon, Chance, Kelly, Flynn, Lawrence E., Krotkov, Nickolay A., Lamsal, Lok, Li, Can, Liu, Xiong, Chan Miller, Christopher, Nowlan, Caroline R., Suleiman, Raid, and Wang, Huiqun. 2019. "Five decades observing Earth's atmospheric trace gases using ultraviolet and visible backscatter solar radiation from space." Journal of Quantitative Spectroscopy and Radiative Transfer 238:106478. https://doi.org/10.1016/j.jqsrt.2019.04.030
ID: 154602
Type: article
Authors: Gonzalez Abad, Gonzalo; Souri, Amir Hossein; Bak, Juseon; Chance, Kelly; Flynn, Lawrence E.; Krotkov, Nickolay A.; Lamsal, Lok; Li, Can; Liu, Xiong; Chan Miller, Christopher; Nowlan, Caroline R.; Suleiman, Raid; Wang, Huiqun
Abstract: Over the last five decades, Earth's atmosphere has been extensively monitored from space using different spectral ranges. Early efforts were directed at improving weather forecasts with the first meteorological satellites launched in the 1960s. Soon thereafter, the intersection between weather, climate and atmospheric chemistry led to the observation of atmospheric composition from space. During the 1970s the Nimbus satellite program started regular monitoring of ozone integrated columns and water vapor profiles using the Backscatter Ultraviolet Spectrometer, the Infrared Interferometer Spectrometer and the Satellite Infrared Spectrometer instruments. Five decades after these pioneer efforts, continuous progress in instrument design, and retrieval techniques allow researchers to monitor tropospheric concentrations of a wide range of species with implications for air quality, climate and weather. The time line of historic, present and future space-borne instruments measuring ultraviolet and visible backscattered solar radiation designed to quantify atmospheric trace gases is presented. We describe the instruments technological evolution and the basic concepts of retrieval theory. We include a review of algorithms developed for ozone, nitrogen dioxide, sulfur dioxide, formaldehyde, bromine monoxide, water vapor and glyoxal, a selection of studies using these algorithms, the challenges they face and how these challenges can be addressed. The paper ends by providing insights on the opportunities that new instruments will bring to the atmospheric chemistry, weather and air quality communities and how to address the pressing need for long-term, inter-calibrated data records necessary to monitor the response of the atmosphere to rapidly changing ecosystems.