The Experts below are selected from a list of 6636 Experts worldwide ranked by ideXlab platform
R. V. Martin - One of the best experts on this subject based on the ideXlab platform.
-
stratosphere troposphere separation of nitrogen dioxide columns from the tempo geostationary Satellite Instrument
Atmospheric Measurement Techniques, 2018Co-Authors: R. V. Martin, E J Bucsela, Jeffrey A Geddes, C A Mclinden, D J M CunninghamAbstract:Separating the stratospheric and tropospheric contributions in Satellite retrievals of atmospheric NO 2 column abundance is a crucial step in the interpretation and application of the Satellite observations. A variety of stratosphere-troposphere separation algorithms have been developed for sun-synchronous Instruments in low Earth orbit (LEO) that benefit from global coverage, including broad clean regions with negligible tropospheric NO 2 compared to stratospheric NO 2 . These global sun-synchronous algorithms need to be evaluated and refined for forthcoming geostationary Instruments focused on continental regions, which lack this global context and require hourly estimates of the stratospheric column. Here we develop and assess a spatial filtering algorithm for the upcoming TEMPO geostationary Instrument that will target North America. Developments include using independent Satellite observations to identify likely locations of tropospheric enhancements, using independent LEO observations for spatial context, consideration of diurnally-varying partial fields of regard, and a filter based on stratospheric to tropospheric air mass factor ratios. We test the algorithm with LEO observations from the OMI Instrument with an afternoon overpass, and from the GOME-2 Instrument with a morning overpass. We compare our TEMPO field of regard algorithm against an identical global algorithm to investigate the penalty resulting from the limited spatial coverage in geostationary orbit, and find excellent agreement in the estimated mean daily tropospheric NO 2 column densities (R 2 = 0.999, slope = 1.009 for July and R 2 = 0.998, slope = 0.999 for January). The algorithm performs well even when only small parts of the continent are observed by TEMPO. The algorithm is challenged the most by east coast morning retrievals in the wintertime (e.g. R 2 = 0.995, slope = 1.038 at 1400 UTC). We find independent global low Earth observations (corrected for time of day) provide important context near the field-of-regard edges. We also test the performance of the TEMPO algorithm without these supporting global observations. Most of the continent is unaffected (R 2 = 0.924 and slope = 0.973 for July and R 2 = 0.996 and slope = 1.008 for January), with 90 % of the pixels having differences of less than ±0.2 x 1015 molecules cm −2 between the TEMPO tropospheric NO 2 column density and the global algorithm. For near-real-time retrieval, even a climatological estimate of the stratospheric NO 2 surrounding the field of regard would improve this agreement. In general, the additional penalty of a limited field of regard from TEMPO introduces no more error than normally expected in most global stratosphere-troposphere separation algorithms. Overall, we conclude that hourly near-real-time stratosphere-troposphere separation for the retrieval of NO 2 tropospheric column densities by the TEMPO geostationary Instrument is both feasible and robust, regardless of the diurnally-varying limited field of regard.
-
estimating ground level pm 2 5 in eastern china using aerosol optical depth determined from the goci Satellite Instrument
Atmospheric Chemistry and Physics, 2015Co-Authors: J. Xu, R. V. Martin, A. Van Donkelaar, M. Choi, Q. Zhang, G. Geng, L. Huang, Yuxuan WangAbstract:Abstract. We determine and interpret fine particulate matter (PM2.5) concentrations in eastern China for January to December 2013 at a horizontal resolution of 6 km from aerosol optical depth (AOD) retrieved from the Korean geostationary ocean color imager (GOCI) Satellite Instrument. We implement a set of filters to minimize cloud contamination in GOCI AOD. Evaluation of filtered GOCI AOD with AOD from the Aerosol Robotic Network (AERONET) indicates significant agreement with mean fractional bias (MFB) in Beijing of 6.7 % and northern Taiwan of −1.2 %. We use a global chemical transport model (GEOS-Chem) to relate the total column AOD to the near-surface PM2.5. The simulated PM2.5 / AOD ratio exhibits high consistency with ground-based measurements in Taiwan (MFB = −0.52 %) and Beijing (MFB = −8.0 %). We evaluate the Satellite-derived PM2.5 versus the ground-level PM2.5 in 2013 measured by the China Environmental Monitoring Center. Significant agreement is found between GOCI-derived PM2.5 and in situ observations in both annual averages (r2 = 0.66, N = 494) and monthly averages (relative RMSE = 18.3 %), indicating GOCI provides valuable data for air quality studies in Northeast Asia. The GEOS-Chem simulated chemical composition of GOCI-derived PM2.5 reveals that secondary inorganics (SO42-, NO3-, NH4+) and organic matter are the most significant components. Biofuel emissions in northern China for heating increase the concentration of organic matter in winter. The population-weighted GOCI-derived PM2.5 over eastern China for 2013 is 53.8 μg m−3, with 400 million residents in regions that exceed the Interim Target-1 of the World Health Organization.
-
interpreting the ultraviolet aerosol index observed with the omi Satellite Instrument to understand absorption by organic aerosols implications for atmospheric oxidation and direct radiative effects
Atmospheric Chemistry and Physics, 2015Co-Authors: Melanie S Hammer, R. V. Martin, Aaron Van Donkelaar, V Buchard, Omar Torres, D A Ridley, Robert SpurrAbstract:Abstract. Satellite observations of the ultraviolet aerosol index (UVAI) are sensitive to absorption of solar radiation by aerosols; this absorption affects photolysis frequencies and radiative forcing. We develop a global simulation of the UVAI using the 3-D chemical transport model GEOS-Chem coupled with the Vector Linearized Discrete Ordinate Radiative Transfer model (VLIDORT). The simulation is applied to interpret UVAI observations from the Ozone Monitoring Instrument (OMI) for the year 2007. Simulated and observed values are highly consistent in regions where mineral dust dominates the UVAI, but a large negative bias (−0.32 to −0.97) exists between simulated and observed values in biomass burning regions. We determine effective optical properties for absorbing organic aerosol, known as brown carbon (BrC), and implement them into GEOS-Chem to better represent observed UVAI values over biomass burning regions. The inclusion of absorbing BrC decreases the mean bias between simulated and OMI UVAI values from −0.57 to −0.09 over West Africa in January, from −0.32 to +0.0002 over South Asia in April, from −0.97 to −0.22 over southern Africa in July, and from −0.50 to +0.33 over South America in September. The spectral dependence of absorption after including BrC in the model is broadly consistent with reported observations for biomass burning aerosol, with absorbing Angstrom exponent (AAE) values ranging from 2.9 in the ultraviolet (UV) to 1.3 across the UV–Near IR spectrum. We assess the effect of the additional UV absorption by BrC on atmospheric photochemistry by examining tropospheric hydroxyl radical (OH) concentrations in GEOS-Chem. The inclusion of BrC decreases OH by up to 30 % over South America in September, up to 20 % over southern Africa in July, and up to 15 % over other biomass burning regions. Global annual mean OH concentrations in GEOS-Chem decrease due to the presence of absorbing BrC, increasing the methyl chloroform lifetime from 5.62 to 5.68 years, thus reducing the bias against observed values. We calculate the direct radiative effect (DRE) of BrC using GEOS-Chem coupled with the radiative transfer model RRTMG (GC-RT). Treating organic aerosol as containing more strongly absorbing BrC changes the global annual mean all-sky top of atmosphere (TOA) DRE by +0.03 W m−2 and all-sky surface DRE by −0.08 W m−2. Regional changes of up to +0.3 W m−2 at TOA and down to −1.5 W m−2 at the surface are found over major biomass burning regions.
-
Estimating ground-level PM2.5 in Eastern China using aerosol optical depth determined from the GOCI Satellite Instrument
Atmospheric Chemistry and Physics Discussions, 2015Co-Authors: J. Xu, R. V. Martin, A. Van Donkelaar, M. Choi, Q. Zhang, G. Geng, Z. Ma, L. HuangAbstract:Abstract. We determine and interpret fine particulate matter (PM2.5) concentrations in East China for January to December 2013 at a horizontal resolution of 6 km from aerosol optical depth (AOD) retrieved from the Korean Geostationary Ocean Color Imager (GOCI) Satellite Instrument. We implement a set of filters to minimize cloud contamination in GOCI AOD. Evaluation of filtered GOCI AOD with AOD from the Aerosol Robotic Network (AERONET) indicates significant agreement with mean fractional bias (MFB) in Beijing of 6.7 % and northern Taiwan of −1.2 %. We use a global chemical transport model (GEOS-Chem) to relate the total column AOD to the near-surface PM2.5. The simulated PM2.5/AOD ratio exhibits high consistency with ground-based measurements (MFB = −0.52–8.0 %). We evaluate the Satellite-derived PM2.5 vs. the ground-level PM2.5 in 2013 measured by the China Environmental Monitoring Center. Significant agreement is found between GOCI-derived PM2.5 and in-situ observations in both annual averages (r = 0.81, N = 494) and monthly averages (MFB = 13.1 %), indicating GOCI provides valuable data for air quality studies in Northeast Asia. The GEOS-Chem simulated chemical speciation of GOCI-derived PM2.5 reveals that secondary inorganics (SO42−, NO3−, NH4+) and organic matter are the most significant components. Biofuel emissions in northern China for heating are responsible for an increase in the concentration of organic matter in winter. The population-weighted GOCI-derived PM2.5 over East China for 2013 is 53.8 μg m−3, threatening the health and life expectancy of its 600 million residents.
-
Assessing the Parameterization of Nitric Oxide Emissions By Lightning in a Chemical Transport Model with Nitric Acid Columns from the IASI Satellite Instrument
2014Co-Authors: Matthew J Cooper, R. V. Martin, Catherine Wespes, Pierrefrancois Coheur, Cathy Clerbaux, Lee T MurrayAbstract:Nitrogen oxides (NOx ≡ NO + NO2) in the free troposphere largely control the production of ozone (O3), an important greenhouse gas and atmospheric oxidant. As HNO3 is the dominant sink of tropospheric NOx, improved understanding of its production and loss mechanisms can help to better constrain NOx emissions, and in turn improve understanding of ozone production and its effect on climate. However, this understanding is inhibited by the scarcity of direct measurements of free tropospheric HNO3, particularly in the tropics. We interpret tropical tropospheric nitric acid columns from the IASI Satellite Instrument with a global chemical transport model (GEOS-Chem). Overall GEOS-Chem generally agrees with IASI, however we find that the simulation underestimates IASI nitric acid over Southeast Asia by a factor of two. The bias is confirmed by comparing the GEOS-Chem simulation with additional Satellite (HIRDLS, ACE-FTS) and aircraft (PEM-Tropics A and PEM-West B) observations of the middle and upper troposphere. We show that this bias can be explained by the parameterization of lightning NOx emissions, primarily from the misrepresentation of concentrated subgrid lightning NOx plumes. We tested a subgrid lightning plume parameterization and found that an additional 0.5 Tg N with an ozone production efficiency of 15 mol/mol would reduce the regional nitric acid bias from 92% to 6% without perturbing the rest of the tropics. Other sensitivity studies such as modified NOx yield per flash, increased altitude of lightning NOx emissions, or changes to convective mass flux or wet deposition of nitric acid required unrealistic changes to reduce the bias. This work demonstrates the importance of a comprehensive lightning parameterization to constraining NOx emissions.
Cathy Clerbaux - One of the best experts on this subject based on the ideXlab platform.
-
Tropospheric column ozone variability from space: results from the first multi-Instrument intercomparison .
2018Co-Authors: Audrey Gaudel, Cathy Clerbaux, Owen Cooper, Valérie Thouret, Brice Barret, Anne Boynard, John Burrows, Guanyu Huang, Brian Kerridge, Barry LatterAbstract:Tropospheric ozone is a pollutant detrimental to human health and crop and ecosystem productivity. Tropospheric ozone is also the third most important greenhouse gas (after CO2 and methane), responsible for ~17% of global radiative forcing since 1750. However, the lack of a comprehensive global ozone monitoring network means that ozone’s radiative forcing must be estimated by chemistry-climate models with a large error bars of ± 50% due to model uncertainties (0.40 ± 0.20 W m-2, according to the fifth IPCC assessment report). Improvements to this estimate require an accurate observation- based quantification of the present-day tropospheric ozone burden (TOB), and greater confidence in chemistry-climate model estimates of TOB in pre-industrial times. TOB is the total mass (Tg) of ozone in the troposphere, calculated by summing all of the tropospheric column ozone (TCO) values at every point on Earth. Presently there is one published observation-based estimate of TOB, which comes from the OMI/MLS Satellite Instruments on NASA’s Aura Satellite. Recently, four new Satellite products have been developed for measuring TCO and TOB, with two based on the OMI Satellite Instrument and two based on the IASI Satellite Instrument. The first intercomparison of these products will soon be published as a component of the Tropospheric Ozone Assessment Report (TOAR). While all five products show the same general tropospheric ozone features across the globe, they differ in absolute TCO quantities and they also differ in terms of decadal trends. The next step is to evaluate all products against the exact same set of in situ ozone observations to gauge the performance of each product in different regions of the world. We will present preliminary results from this evaluation which relies on daily IAGOS commercial aircraft profiles above Frankfurt, Germany and weekly NOAA GMD ozonesonde profiles above Hilo, Hawaii; Trinidad Head, California; and Boulder, Colorado.
-
Assessing the Parameterization of Nitric Oxide Emissions By Lightning in a Chemical Transport Model with Nitric Acid Columns from the IASI Satellite Instrument
2014Co-Authors: Matthew J Cooper, R. V. Martin, Catherine Wespes, Pierrefrancois Coheur, Cathy Clerbaux, Lee T MurrayAbstract:Nitrogen oxides (NOx ≡ NO + NO2) in the free troposphere largely control the production of ozone (O3), an important greenhouse gas and atmospheric oxidant. As HNO3 is the dominant sink of tropospheric NOx, improved understanding of its production and loss mechanisms can help to better constrain NOx emissions, and in turn improve understanding of ozone production and its effect on climate. However, this understanding is inhibited by the scarcity of direct measurements of free tropospheric HNO3, particularly in the tropics. We interpret tropical tropospheric nitric acid columns from the IASI Satellite Instrument with a global chemical transport model (GEOS-Chem). Overall GEOS-Chem generally agrees with IASI, however we find that the simulation underestimates IASI nitric acid over Southeast Asia by a factor of two. The bias is confirmed by comparing the GEOS-Chem simulation with additional Satellite (HIRDLS, ACE-FTS) and aircraft (PEM-Tropics A and PEM-West B) observations of the middle and upper troposphere. We show that this bias can be explained by the parameterization of lightning NOx emissions, primarily from the misrepresentation of concentrated subgrid lightning NOx plumes. We tested a subgrid lightning plume parameterization and found that an additional 0.5 Tg N with an ozone production efficiency of 15 mol/mol would reduce the regional nitric acid bias from 92% to 6% without perturbing the rest of the tropics. Other sensitivity studies such as modified NOx yield per flash, increased altitude of lightning NOx emissions, or changes to convective mass flux or wet deposition of nitric acid required unrealistic changes to reduce the bias. This work demonstrates the importance of a comprehensive lightning parameterization to constraining NOx emissions.
-
tropospheric nitric acid columns from the iasi Satellite Instrument interpreted with a chemical transport model implications for parameterizations of nitric oxide production by lightning
Journal of Geophysical Research, 2014Co-Authors: Matthew J Cooper, R. V. Martin, Catherine Wespes, Pierrefrancois Coheur, Cathy Clerbaux, Lee T MurrayAbstract:This paper interprets tropical tropospheric nitric acid columns from the Infrared Atmospheric Sounding Interferometer (IASI) Satellite Instrument with a global chemical transport model (GEOS-Chem). GEOS-Chem and IASI columns generally agree over the tropical ocean to within 10%. However, the GEOS-Chem simulation underestimates IASI nitric acid over Southeast Asia by a factor of 2. The regional nitric acid bias is confirmed by comparing the GEOS-Chem simulation with additional Satellite (High Resolution Dynamics Limb Sounder, Atmospheric Chemistry Experiment Fourier Transform Spectrometer) and aircraft (Pacific Exploratory Mission (PEM)-Tropics A and PEM-West B) observations of the middle and upper troposphere. This bias appears to be driven by the lightning NOx parameterization, both in terms of the magnitude of the NOx source and the ozone production efficiency of concentrated lightning NOx plumes. We tested a subgrid lightning plume parameterization and found that an ozone production efficiency of 15 mol/mol in lightning plumes over Southeast Asia in conjunction with an additional 0.5 Tg N would reduce the regional nitric acid bias from 92% to 6% without perturbing the rest of the tropics. Other sensitivity studies such as modified NOx yield per flash, increased altitude of lightning NOx emissions, decreased convective mass flux, or increased scavenging of nitric acid required unrealistic changes to reduce the bias.
-
CO measurements from the ACE-FTS Satellite Instrument: data analysis and validation using ground-based, airborne and spaceborne observations
Atmospheric Chemistry and Physics, 2008Co-Authors: Cathy Clerbaux, Solene Turquety, Maya George, K. A. Walker, B. Barret, P. Bernath, C. Boone, T. Borsdorff, Jean-pierre Cammas, Valéry CatoireAbstract:The Atmospheric Chemistry Experiment (ACE) mission was launched in August 2003 to sound the atmosphere by solar occultation. Carbon monoxide (CO), a good tracer of pollution plumes and atmospheric dynamics, is one of the key species provided by the primary Instrument, the ACE-Fourier Transform Spectrometer (ACE-FTS). This Instrument performs measurements in both the CO 1-0 and 2-0 ro-vibrational bands, from which vertically resolved CO concentration profiles are retrieved, from the mid-troposphere to the thermosphere. This paper presents an updated description of the ACE-FTS version 2.2 CO data product, along with a comprehensive validation of these profiles using available observations (February 2004 to December 2006). We have compared the CO partial columns with ground-based measurements using Fourier transform infrared spectroscopy and millimeter wave radiometry, and the volume mixing ratio profiles with airborne (both high-altitude balloon flight and airplane) observations. CO Satellite observations provided by nadir-looking Instruments (MOPITT and TES) as well as limb-viewing remote sensors (MIPAS, SMR and MLS) were also compared with the ACE-FTS CO products. We show that the ACE-FTS measurements provide CO profiles with small retrieval errors (better than 5% from the upper troposphere to 40 km, and better than 10% above). These observations agree well with the correlative measurements, considering the rather loose coincidence criteria in some cases. Based on the validation exercise we assess the following uncertainties to the ACE-FTS measurement data: better than 15% in the upper troposphere (8–12 km), than 30% in the lower stratosphere (12–30 km), and than 25% from 30 to 100 km.
H M Worden - One of the best experts on this subject based on the ideXlab platform.
-
ch 4 and co distributions over tropical fires during october 2006 as observed by the aura tes Satellite Instrument and modeled by geos chem
Atmospheric Chemistry and Physics, 2013Co-Authors: John Worden, K W Bowman, K. Wecht, Christian Frankenberg, Matthew J. Alvarado, Eric A. Kort, Susan S. Kulawik, Vivienne H. Payne, H M WordenAbstract:Abstract. Tropical fires represent a highly uncertain source of atmospheric methane (CH 4 ) because of the variability of fire emissions and the dependency of the fire CH 4 emission factors (g kg −1 dry matter burned) on fuel type and combustion phase. In this paper we use new observations of CH 4 and CO in the free troposphere from the Aura Tropospheric Emission Sounder (TES) Satellite Instrument to place constraints on the role of tropical fire emissions versus microbial production (e.g. in wetlands and livestock) during the (October) 2006 El Nino, a time of significant fire emissions from Indonesia. We first compare the global CH 4 distributions from TES using the GEOS-Chem model. We find a mean bias between the observations and model of 26.3 ppb CH 4 that is independent of latitude between 50° S and 80° N, consistent with previous validation studies of TES CH 4 retrievals using aircraft measurements. The slope of the distribution of CH 4 versus CO as observed by TES and modeled by GEOS-Chem is consistent (within the TES observation error) for air parcels over the Indonesian peat fires, South America, and Africa. The CH 4 and CO distributions are correlated between R = 0.42 and R = 0.46, with these correlations primarily limited by the TES random error. Over Indonesia, the observed slope of 0.13 (ppb ppb −1 ) ±0.01, as compared to a modeled slope of 0.153 (ppb ppb −1 ) ±0.005 and an emission ratio used within the GEOS-Chem model of approximately 0.11 (ppb ppb −1 ), indicates that most of the observed methane enhancement originated from the fire. Slopes of 0.47 (ppb ppb −1 ) ±0.04 and 0.44 (ppb ppb −1 ) ±0.03 over South America and Africa show that the methane in the observed air parcels primarily came from microbial-generated emissions. Sensitivity studies using GEOS-Chem show that part of the observed correlation for the Indonesian observations and most of the observed correlations over South America and Africa are a result of transport and mixing of the fire and nearby microbial-generated emissions into the observed air parcels. Differences between observed and modeled CH 4 distributions over South America and southern Africa indicate that the magnitude of the methane emissions for this time period are inconsistent with observations even if the relative distribution of fire versus biotic emissions are consistent. This study shows the potential for estimation of CH 4 emissions over tropical regions using joint Satellite observations of CH 4 and CO.
-
ozone co correlations determined by the tes Satellite Instrument in continental outflow regions
Geophysical Research Letters, 2006Co-Authors: Lin Zhang, Daniel J Jacob, K W Bowman, Jennifer A Logan, Solene Turquety, R C Hudman, Qinbin Li, R Beer, H M WordenAbstract:0.4– 1.0 mol mol � 1 and consistent with ICARTT data. The GEOS-Chem model reproduces the O3-CO enhancement ratios observed in continental outflow, but model correlations are stronger and more extensive. We show that the discrepancy can be explained by spectral measurement errors in the TES data. These errors will decrease in future data releases, which should enable TES to provide better information on O3-CO correlations. Citation: Zhang, L., et al. (2006), Ozone-CO correlations determined by the TES Satellite Instrument in continental outflow regions, Geophys. Res. Lett., 33, L18804, doi:10.1029/2006GL026399.
Daniel J Jacob - One of the best experts on this subject based on the ideXlab platform.
-
spatial distribution and temporal trend of ozone pollution inchina observed with the omi Satellite Instrument 2005 2017
Atmospheric Chemistry and Physics, 2018Co-Authors: Lu Shen, Daniel J Jacob, Guanyu Huang, Ke Li, Hong LiaoAbstract:Abstract. We use data from the new China Ministry of Ecology and Environment (MEE) network to show that OMI Satellite observations of tropospheric ozone can successfully map the distribution of surface ozone pollution in China and the frequency of high-ozone episodes. After subtracting the Pacific background, OMI ozone enhancements over China can quantify mean summer afternoon surface ozone with a precision of 10.7 ppb and a spatial correlation coefficient R =0.73. Day-to-day correlations between OMI and the MEE ozone data are statistically significant but limited by noise in the individual OMI retrievals. OMI shows significantly higher values on surface ozone episode days (>82 ppb). An extreme value model can successfully predict the probability of surface ozone episodes from the daily OMI data. The 2005–2017 OMI record shows a 0.67 ppb a −1 increase in mean summer afternoon ozone in eastern China and an increasing frequency of ozone pollution episodes particularly in the north.
-
nitrogen oxides in the global upper troposphere interpreting cloud sliced no 2 observations from the omi Satellite Instrument
Atmospheric Chemistry and Physics, 2018Co-Authors: Daniel J Jacob, Lee T Murray, Eloise A. Marais, Sungyeon Choi, Joanna Joiner, Ronald C. Cohen, Steffen Beirle, Maria Belmonterivas, Luke SchiferlAbstract:Abstract. Nitrogen oxides ( NO x ≡ NO + NO 2 ) in the upper troposphere (UT) have a large impact on global tropospheric ozone and OH (the main atmospheric oxidant). New cloud-sliced observations of UT NO2 at 450–280 hPa ( ∼6 –9 km) from the Ozone Monitoring Instrument (OMI) produced by NASA and the Royal Netherlands Meteorological Institute (KNMI) provide global coverage to test our understanding of the factors controlling UT NOx . We find that these products offer useful information when averaged over coarse scales ( 20 ∘ × 32 ∘ , seasonal), and that the NASA product is more consistent with aircraft observations of UT NO2 . Correlation with Lightning Imaging Sensor (LIS) and Optical Transient Detector (OTD) Satellite observations of lightning flash frequencies suggests that lightning is the dominant source of NOx to the upper troposphere except for extratropical latitudes in winter. The NO2 background in the absence of lightning is 10–20 pptv. We infer a global mean NOx yield of 280±80 moles per lightning flash, with no significant difference between the tropics and midlatitudes, and a global lightning NOx source of 5.9±1.7 Tg N a −1 . There is indication that the NOx yield per flash increases with lightning flash footprint and with flash energy.
-
Nitrogen oxides in the global upper troposphere: interpreting cloud-sliced NO<sub>2</sub> observations from the OMI Satellite Instrument
2018Co-Authors: Eloise A. Marais, Daniel J Jacob, Lee T Murray, Sungyeon Choi, Joanna Joiner, Maria Belmonte-rivas, Ronald C. Cohen, Steffen Beirle, Luke Schiferl, Viral ShahAbstract:<p><strong>Abstract.</strong> Nitrogen oxides (NO<sub>x</sub>&#8201;&#8801;&#8201;NO&#8201;+&#8201;NO<sub>2</sub>) in the upper troposphere (UT) have a large impact on global tropospheric ozone and OH (the main atmospheric oxidant). New cloud-sliced observations of UT NO<sub>2</sub> at 450&#8211;280&#8201;hPa (~&#8201;6&#8211;9&#8201;km) from the OMI Satellite Instrument produced by NASA and KNMI provide global coverage to test our understanding of the factors controlling UT NO<sub>x</sub>. We find that these products offer useful information when averaged over coarse scales (20&#176;&#8201;&#215;&#8201;32&#176;, seasonal), and that the NASA product is more consistent with aircraft observations of UT NO<sub>2</sub>. Correlation with LIS/OTD Satellite observations of lightning flash frequencies shows that lightning is the dominant source of NO<sub>x</sub> to the upper troposphere except for extratropical latitudes in winter. We infer a global mean NO<sub>x</sub> yield of 280 moles per lightning flash, with no significant difference between the tropics and mid-latitudes, and a global lightning NO<sub>x</sub> source of 5.6&#8201;Tg&#8201;N&#8201;a<sup>&#8722;1</sup>. There is indication that the NO<sub>x</sub> yield per flash increases with lightning flash footprint and with flash energy.</p>
-
hotspot of glyoxal over the pearl river delta seen from the omi Satellite Instrument implications for emissions of aromatic hydrocarbons
Atmospheric Chemistry and Physics, 2016Co-Authors: Christopher Chan Miller, Daniel J Jacob, Gonzalo Gonzalez Abad, K ChanceAbstract:Abstract. The Pearl River delta (PRD) is a densely populated hub of industrial activity located in southern China. OMI (Ozone Monitoring Instrument) Satellite observations reveal a large hotspot of glyoxal (CHOCHO) over the PRD that is almost twice as large as any other in Asia. Formaldehyde (HCHO) and NO2 observed by OMI are also high in the PRD but no more than in other urban/industrial areas of China. The CHOCHO hotspot over the PRD can be explained by industrial paint and solvent emissions of aromatic volatile organic compounds (VOCs), with toluene being a dominant contributor. By contrast, HCHO in the PRD originates mostly from VOCs emitted by combustion (principally vehicles). By applying a plume transport model to wind-segregated OMI data, we show that the CHOCHO and HCHO enhancements over the PRD observed by OMI are consistent with current VOC emission inventories. Prior work using CHOCHO retrievals from the SCIAMACHY Satellite Instrument suggested that emission inventories for aromatic VOCs in the PRD were too low by a factor of 10–20; we attribute this result in part to bias in the SCIAMACHY data and in part to underestimated CHOCHO yields from oxidation of aromatics. Our work points to the importance of better understanding CHOCHO yields from the oxidation of aromatics in order to interpret space-based CHOCHO observations in polluted environments.
-
Hotspot of Glyoxal Over the Pearl River Delta Seen from the OMI Satellite Instrument: Implications for Emissions of Aromatic Hydrocarbons
2016Co-Authors: Christopher Chan Miller, Daniel J Jacob, Gonzalo González Abad, Kelly ChanceAbstract:<p><strong>Abstract.</strong> The Pearl River Delta (PRD) is a densely populated hub of industrial activity located in southern China. OMI Satellite observations reveal a large hotspot of glyoxal (CHOCHO) over the PRD that is almost twice as large as any other in Asia. Formaldehyde (HCHO) and NO<sub>2</sub> observed by OMI are also high in the PRD but no more than in other urban/industrial areas of China. The CHOCHO hotspot in the PRD can be explained by industrial paint and solvent emissions of aromatic volatile organic compounds (VOCs), with toluene being a dominant contributor. By contrast, HCHO in the PRD originates mostly from VOCs emitted by combustion (principally vehicles). By applying a plume transport model to wind-segregated OMI data, we show that the CHOCHO and HCHO enhancements over the PRD observed by OMI are consistent with current VOC emission inventories. Prior work using CHOCHO retrievals from the SCIAMACHY Satellite Instrument suggested that aromatic VOC emissions in the PRD were too low by a factor of 10-20; we attribute this result in part to bias in the SCIAMACHY data and in part to underestimated CHOCHO yields from oxidation of aromatics. Our work points to the importance of better understanding CHOCHO yields from the oxidation of aromatics in order to interpret CHOCHO observations from space.</p>
Seiji Kato - One of the best experts on this subject based on the ideXlab platform.
-
toward optimal closure of the earth s top of atmosphere radiation budget
Journal of Climate, 2009Co-Authors: Norman G Loeb, Bruce A Wielicki, David R Doelling, Louis G Smith, Dennis F Keyes, Seiji Kato, Natividad Manalosmith, Takmeng WongAbstract:Abstract Despite recent improvements in Satellite Instrument calibration and the algorithms used to determine reflected solar (SW) and emitted thermal (LW) top-of-atmosphere (TOA) radiative fluxes, a sizeable imbalance persists in the average global net radiation at the TOA from Satellite observations. This imbalance is problematic in applications that use earth radiation budget (ERB) data for climate model evaluation, estimate the earth’s annual global mean energy budget, and in studies that infer meridional heat transports. This study provides a detailed error analysis of TOA fluxes based on the latest generation of Clouds and the Earth’s Radiant Energy System (CERES) gridded monthly mean data products [the monthly TOA/surface averages geostationary (SRBAVG-GEO)] and uses an objective constrainment algorithm to adjust SW and LW TOA fluxes within their range of uncertainty to remove the inconsistency between average global net TOA flux and heat storage in the earth–atmosphere system. The 5-yr global mean...
-
top of atmosphere direct radiative effect of aerosols over the tropical oceans from the clouds and the earth s radiant energy system ceres Satellite Instrument
Journal of Climate, 2002Co-Authors: Norman G Loeb, Seiji KatoAbstract:Abstract Nine months of the Clouds and the Earth's Radiant Energy System (CERES)/Tropical Rainfall Measuring Mission (TRMM) broadband fluxes combined with the TRMM visible infrared scanner (VIRS) high-resolution imager measurements are used to estimate the daily average direct radiative effect of aerosols for clear-sky conditions over the tropical oceans. On average, aerosols have a cooling effect over the Tropics of 4.6 ± 1 W m–2. The magnitude is ≈2 W m–2 smaller over the southern tropical oceans than it is over northern tropical oceans. The direct effect derived from CERES is highly correlated with coincident aerosol optical depth (τ) retrievals inferred from 0.63-μm VIRS radiances (correlation coefficient of 0.96). The slope of the regression line is ≈−32 W m–2 τ–1 over the equatorial Pacific Ocean, but changes both regionally and seasonally, depending on the aerosol characteristics. Near sources of biomass burning and desert dust, the aerosol direct effect reaches −25 to −30 W m–2. The direct effect ...
