Julie M. Nicely
A5090607923- Atmospheric and Environmental Gas Dynamics
- Atmospheric chemistry and aerosols
- Atmospheric Ozone and Climate
- Air Quality Monitoring and Forecasting
- Spectroscopy and Laser Applications
- Atmospheric aerosols and clouds
- Water Quality Monitoring and Analysis
- Laser Design and Applications
- Ocean Acidification Effects and Responses
- Catalytic Processes in Materials Science
- Methane Hydrates and Related Phenomena
- Ionosphere and magnetosphere dynamics
- Medical Imaging Techniques and Applications
- Advanced Optical Sensing Technologies
- Retinoids in leukemia and cellular processes
- Vehicle emissions and performance
- Meteorological Phenomena and Simulations
- Radiation Therapy and Dosimetry
- Estrogen and related hormone effects
- Remote Sensing and LiDAR Applications
- Astro and Planetary Science
- Free Radicals and Antioxidants
- Nuclear and radioactivity studies
- Hydrocarbon exploration and reservoir analysis
- Environmental Impact and Sustainability
Earth System Science Interdisciplinary Center
2019-2024
Goddard Space Flight Center
2016-2024
University of Maryland, College Park
2015-2024
Earth Resources Technology (United States)
2024
National Aeronautics and Space Administration
2023
University of Maryland, Baltimore County
2019
Systems Technology (United States)
2019
Universities Space Research Association
2017-2018
Science Systems and Applications (United States)
2018
Duke University
2015
The Goddard Earth Observing System composition forecast (GEOS-CF) system is a high-resolution (0.25°) global constituent prediction from NASA's Global Modeling and Assimilation Office (GMAO). GEOS-CF offers new tool for atmospheric chemistry research, with the goal to supplement broad range of space-based in-situ observations. expands on GEOS weather aerosol modeling by introducing GEOS-Chem module provide hindcasts 5-days forecasts constituents including ozone (O
The hydroxyl radical (OH) fuels tropospheric ozone production and governs the lifetime of methane many other gases. Existing methods to quantify global OH are limited annual global-to-hemispheric averages. Finer resolution is essential for isolating model deficiencies building process-level understanding. In situ observations from Atmospheric Tomography (ATom) mission demonstrate that remote tightly coupled loss formaldehyde (HCHO), a major hydrocarbon oxidation product. Synthesis this...
Abstract This article provides an overview of the NASA Atmospheric Tomography (ATom) mission and a summary selected scientific findings to date. ATom was airborne measurements modeling campaign aimed at characterizing composition chemistry troposphere over most remote regions Pacific, Southern, Atlantic, Arctic Oceans, examining impact anthropogenic natural emissions on global scale. These dominate chemical reactivity are exceptionally important for air quality climate. data provide in situ...
Abstract The Convective Transport of Active Species in the Tropics (CONTRAST) experiment was conducted from Guam (13.5°N, 144.8°E) during January–February 2014. Using NSF/NCAR Gulfstream V research aircraft, investigated photochemical environment over tropical western Pacific (TWP) warm pool, a region massive deep convection and major pathway for air to enter stratosphere Northern Hemisphere (NH) winter. new observations provide wealth information quantifying influence on vertical...
Abstract The oxidizing capacity of the troposphere is controlled primarily by abundance hydroxyl radical (OH). global mean concentration tropospheric OH, [OH] TROP (the burden OH in appropriate for calculating lifetime methane) inferred from measurements methyl chloroform has remained relatively constant during past several decades despite rising levels methane that should have led to a decline. Here we examine other factors may affected such as changing values stratospheric ozone, H 2 O,...
Abstract Earth's atmosphere oxidizes the greenhouse gas methane and other gases, thus determining their lifetimes oxidation products. Much of this occurs in remote, relatively clean free troposphere above planetary boundary layer, where chemistry is thought to be much simpler better understood than it urban regions or forests. The NASA airborne Atmospheric Tomography study (ATom) was designed produce cross sections detailed atmospheric composition remote over Pacific Atlantic Oceans during...
The hydroxyl radical (OH) fuels atmospheric chemical cycling as the main sink for methane and a driver of formation loss many air pollutants, but direct OH observations are sparse. We develop evaluate an observation-based proxy short-term, spatial variations in (Proxy
Abstract Formaldehyde (HCHO) directly affects the atmospheric oxidative capacity through its effects on HO x . In remote marine environments, such as tropical western Pacific (TWP), it is particularly important to understand processes controlling abundance of HCHO because model output from these regions used correct satellite retrievals HCHO. Here we have observations Convective Transport Active Species in Tropics (CONTRAST) field campaign, conducted during January and February 2014,...
Abstract The hydroxyl radical (OH) is the primary daytime oxidant in troposphere and provides main loss mechanism for many pollutants greenhouse gases, including methane (CH 4 ). Global mean tropospheric OH differs by as much 80% among various global models, reasons that are not well understood. We use neural networks (NNs), trained using archived output from eight chemical transport models (CTMs) participated Polar Study Aircraft, Remote Sensing, Surface Measurements Models, of Climate,...
Abstract. The hydroxyl radical (OH) is the primary atmospheric oxidant responsible for removing many important trace gases, including methane, from atmosphere. Although robust relationships between OH drivers and modes of climate variability have been shown, underlying mechanisms these modes, such as El Niño–Southern Oscillation (ENSO), not thoroughly investigated. Here, we use a chemical transport model to perform 38 year simulation chemistry, in conjunction with satellite observations,...
Abstract Air parcels with mixing ratios of high O 3 and low H 2 (HOLW) are common features in the tropical western Pacific (TWP) mid-troposphere (300–700 hPa). Here, using data collected during aircraft sampling TWP winter 2014, we find strong, positive correlations multiple biomass burning tracers these HOLW structures. Ozone levels structures about a factor three larger than background. Models, satellite observations used to show fires Africa Southeast Asia dominant source that results...
Abstract We quantify the stratospheric injection of brominated very short‐lived substances (VSLS) based on aircraft observations acquired in winter 2014 above Tropical Western Pacific during CONvective TRansport Active Species Tropics (CONTRAST) and Airborne TRopopause EXperiment (ATTREX) campaigns. The overall contribution VSLS to bromine was determined be 5.0 ± 2.1 ppt, agreement with 5 3 ppt estimate provided World Meteorological Organization (WMO) Ozone Assessment report (WMO 2014), but...
Abstract. The hydroxyl radical (OH) plays critical roles within the troposphere, such as determining lifetime of methane (CH4), yet is challenging to model due its fast cycling and dependence on a multitude sources sinks. As result, reasons for variations in OH resulting (τCH4), both between models time, are difficult diagnose. We apply neural network (NN) approach address this issue group that participated Chemistry-Climate Model Initiative (CCMI). Analysis historical specified dynamics...
Abstract. The hydroxyl radical (OH) reacts with thousands of chemical species in the atmosphere, initiating their removal and reaction sequences that produce ozone, secondary aerosols, gas-phase acids. OH reactivity, which is inverse lifetime, influences abundance ability to cleanse atmosphere. NASA Atmospheric Tomography (ATom) campaign used instruments on DC-8 aircraft measure reactivity more than 100 trace species. ATom presented a unique opportunity test completeness calculated from...
Abstract Despite its importance for the global oxidative capacity, spatially resolved trends and variability of hydroxyl radical (OH) are poorly constrained. We demonstrate utility a tropospheric column OH (TCOH) product, created from machine learning satellite proxy data, in determining spatial tropical over oceans during September through November. While increases domain‐wide by 2.1%/decade 2005–2019, we find significant heterogeneity regional trends, with decreases some areas 2.5%/decade....
Abstract. Formaldehyde (HCHO) in the atmosphere is an intermediate product from oxidation of methane and non-methane volatile organic compounds. In remote marine regions, HCHO variability closely related to atmospheric capacity, modeled these regions usually added as a global satellite background. Thus, it important understand validate levels over oceans. Here we intercompare three retrievals total columns Ozone Monitoring Instrument Smithsonian Astrophysical Observatory (OMI SAO (v004))...
Abstract Hydroxyl radical (OH) is the main daytime oxidant in troposphere and determines atmospheric lifetimes of many compounds. We use aircraft measurements O 3 , H 2 O, NO, other species from Convective Transport Active Species Tropics (CONTRAST) field campaign, which occurred tropical western Pacific (TWP) during January–February 2014, to constrain a photochemical box model estimate concentrations OH throughout troposphere. find that tropospheric column (OH COL ) inferred CONTRAST...
Abstract Many Chemistry‐Climate Models (CCMs) include a simplified treatment of brominated very short‐lived (VSL Br ) species by assuming CH 3 as surrogate for VSL . However, neglecting comprehensive in CCMs may yield an unrealistic representation the associated impacts. Here, we use Community Atmospheric Model with Chemistry (CAM‐Chem) CCM to quantify tropospheric and stratospheric changes between various chemical approaches increasing degrees complexity (i.e., surrogate, explicit, full)....
Abstract. Formaldehyde (HCHO) in the atmosphere is an intermediate product from oxidation of methane and non-methane volatile organic compounds. In remote marine regions, HCHO variability closely related to atmospheric capacity modeled these regions usually added as a global satellite background. Thus, it important understand validate levels over oceans. Here we intercompare three retrievals total columns (OMI-SAO (v004), OMPS-NPP SAO, OMI BIRA) them against situ observations NASA...
The hydroxyl radical (OH) is the dominant tropospheric oxidant and therefore responsible for setting lifetime of several key atmospheric constituents, including methane. Despite its importance, however, there are no global in situ or remote sensing networks that directly observe this species. Methyl chloroform (MCF) inversions, often used to infer interannual variability trends OH, only provide information at hemispheric scales have become less reliable as MCF concentrations decline. This...
Earth and Space Science Open Archive This preprint has been submitted to is under consideration at Journal of Advances in Modeling Systems (JAMES). ESSOAr a venue for early communication or feedback before peer review. Data may be preliminary.Learn more about preprints preprintOpen AccessYou are viewing the latest version by default [v1]Description NASA GEOS Composition Forecast System GEOS-CF v1.0AuthorsChristoph A.KelleriDK. EmmaKnowlandBryan NDuncanJunhuaLiuDaniel...
Abstract. We present a methodology that uses gradient-boosted regression trees (a machine learning technique) and full-chemistry simulation (i.e., training dataset) from chemistry–climate model (CCM) to efficiently generate parameterization of tropospheric hydroxyl radical (OH) is function chemical, dynamical, solar irradiance variables. This surrogate OH designed be integrated into CCM allow for computationally efficient nonlinear feedbacks between constituents have loss by reaction with as...
Abstract. Despite its importance in controlling the abundance of methane (CH4) and a myriad other tropospheric species, hydroxyl radical (OH) is poorly constrained due to large spatial heterogeneity inability measure OH with satellites. Here, we present methodology infer column (TCOH) tropics over open oceans using combination machine learning model, output from simulation GEOS satellite observations. Our overall goals are assess feasibility our methodology, identify potential limitations,...