A5071904361- Atmospheric chemistry and aerosols
- Atmospheric and Environmental Gas Dynamics
- Atmospheric Ozone and Climate
- Atmospheric aerosols and clouds
- Fire effects on ecosystems
- Air Quality and Health Impacts
- Lightning and Electromagnetic Phenomena
- Meteorological Phenomena and Simulations
- Air Quality Monitoring and Forecasting
- Ionosphere and magnetosphere dynamics
- Vehicle emissions and performance
- Solidification and crystal growth phenomena
- Metallurgical Processes and Thermodynamics
- Wind and Air Flow Studies
- Solar Radiation and Photovoltaics
- Aluminum Alloy Microstructure Properties
- Gas Dynamics and Kinetic Theory
- Earthquake Detection and Analysis
- Ocean Acidification Effects and Responses
- Astro and Planetary Science
- Urban Heat Island Mitigation
- Combustion and Detonation Processes
- Climate variability and models
- Climate Change Policy and Economics
- Silicon and Solar Cell Technologies
University of Maryland, College Park
2014-2024
NOAA Oceanic and Atmospheric Research
2023-2024
University of Mary
2012-2018
Earth System Science Interdisciplinary Center
2012
Goddard Space Flight Center
1989-2012
Imperial College London
1994
Applied Research Corporation (United States)
1989-1993
Snam (Italy)
1993
University of California, San Diego
1991
University of Oxford
1975-1976
A three‐dimensional (3‐D) cloud‐scale chemical transport model that includes a parameterized source of lightning NO x on the basis observed flash rates has been used to simulate six midlatitude and subtropical thunderstorms during four field projects. Production per intracloud ( P IC ) cloud‐to‐ground CG is estimated by assuming various values for each storm determining which production scenario yields mixing ratios compare most favorably with in‐cloud aircraft observations. We obtain mean...
Four global scale and three regional chemical transport models are intercompared evaluated during NASA's Transport Chemical Evolution over the Pacific (TRACE‐P) experiment. Model simulated measured CO statistically analyzed along aircraft flight tracks. Results for combination of 11 flights show an overall negative bias in CO. Biases most pronounced large events. Statistical agreements vary greatly among individual flights. Those with greatest range values tend to be worst simulated....
Abstract Urban heat island (UHI) effects can strengthen waves and air pollution episodes. In this study, the dampening impact of urban trees on UHI during an extreme wave in Washington, D.C., Baltimore, Maryland, metropolitan area is examined by incorporating trees, soil, grass into coupled Weather Research Forecasting model canopy (WRF-UCM). By parameterizing these natural surfaces alongside roadways buildings, modified WRF-UCM used to investigate how dampen UHI. The was run with 50% tree...
The impact of nitric oxide (NO) emissions by lightning on summertime North American nitrogen oxides (NO x ) and ozone is studied using the Global Modeling Initiative (GMI) CTM an improved NO algorithm. spatial distributions modeled National Lightning Detection Network‐based flash rates during summers 2004–2006 agree well ( R 2 = 0.49, 18% low bias). Despite this reasonable agreement, 9–12 km model Intercontinental Chemical Transport Experiment (INTEX‐A) campaign a factor 2.2–3.6 too for...
Abstract. A lightning-nitrogen oxide (NO) algorithm is implemented in the Community Multiscale Air Quality Model (CMAQ) and used to evaluate impact of lightning-NO emissions (LNOx) on tropospheric photochemistry over United States during summer 2006. For a 500 mole per flash source, mean summertime NO2 column agrees with satellite-retrieved columns within −5 +13%. Temporal fluctuations are moderately well simulated; however, addition LNOx does not lead better simulation day-to-day...
Abstract. Regulatory air quality models, such as the Community Multiscale Air Quality model (CMAQ), are used by federal and state agencies to guide policy decisions that determine how best achieve adherence with National Ambient Standards for surface ozone. We use observations of ozone its important precursor NO2 test representation photochemistry emission precursors within CMAQ. Observations tropospheric column from Ozone Monitoring Instrument (OMI), retrieved two independent groups, show...
Model simulations of tropospheric O 3 require an accurate specification the reactive odd nitrogen (NO x ) source from lightning that is consistent in time and space with convective transport precursors. Lightning NO production global models often parameterized terms cloud top heights (CLDHT). However, a closer relationship may exist between flash rate other measures intensity. In this study, rates are CLDHT, precipitation (PRECON), upward mass flux (MFLUX) Goddard Earth Observing System Data...
Abstract. This paper examines the operational performance of Community Multiscale Air Quality (CMAQ) model simulations for 2002–2006 using both 36-km and 12-km horizontal grid spacing, with a primary focus on CMAQ in predicting wet deposition sulfate (SO4=), ammonium (NH4+) nitrate (NO3−). Performance estimates from is determined by comparing predicted concentrations to measured National Acid Deposition Program (NADP), specifically Trends Network (NTN). For SO4= deposition, were generally...
Abstract We evaluate nitrogen oxide (NO x = NO + 2 ) production from lightning over the Gulf of Mexico region using data Ozone Monitoring Instrument (OMI) aboard NASA's Aura satellite along with detection efficiency‐adjusted World Wide Lightning Location Network (WWLLN). A special algorithm was developed to retrieve (LNO signal OMI. The in its general form takes total slant column OMI and removes stratospheric contribution tropospheric background includes an air mass factor appropriate for...
Abstract Oxides of nitrogen are critical trace gases in the troposphere and precursors for nitrate aerosol ozone, which is an important pollutant greenhouse gas. Lightning major source NO x (NO + 2 ) middle to upper troposphere. We estimate production efficiency (PE) lightning (LNO using satellite data from Ozone Monitoring Instrument ground‐based World Wide Location Network three northern midlatitudes, primarily continental regions that include much North America, Europe, East Asia. Data...
Abstract Nitrogen oxides produced by lightning (LNO x ) play an important role in determining mid‐ and upper‐tropospheric concentrations of the hydroxyl radical (OH), methane (CH 4 ), ozone (O 3 ). The moles NO per flash was examined using nitrogen dioxide (NO 2 columns cloud properties from Tropospheric Monitoring Instrument (TROPOMI) counts Geostationary Lightning Mapper (GLM) aboard Operational Environmental Satellite‐16 (GOES‐16) Earth Networks Total Network (ENTLN) for 29 convective...
The distribution of 222 Rn is simulated using a three‐dimensional chemistry and transport model driven by assimilated data. multiyear calculation the first to use meteorological data from Goddard Earth Observing System assimilation system (GEOS‐1 DAS). In addition, this moist convection boundary layer parameters directly DAS calculate mixing via turbulence. Previously, these quantities have been derived after procedure. Model output are compared at sites selected evaluate performance in...
Transport‐induced interannual variability of carbon monoxide (CO) is studied during 1989–1993 using the Goddard chemistry and transport model (GCTM) driven by assimilated data. Seasonal changes in latitudinal distribution CO near surface at 500 hPa are captured model. The annual cycle reasonably well simulated sites widely varying character. Day to day fluctuations due synoptic waves reproduced accurately remote North Atlantic locations. By fixing location magnitude chemical sources sinks,...
Abstract The sensitivity of tropical tropospheric composition to the source strength nitrogen oxides (NO x ) produced by lightning (LNO is analyzed for September through November 2007 using NASA GEOS‐5 model constrained MERRA fields, with full GMI stratospheric‐tropospheric chemistry and an LNO algorithm that appropriate use in a climate modeling setting; satellite retrievals from OMI, TES, OMI/MLS; situ measurements SHADOZ ozonesondes. Global mean production rates 0 492 mol NO flash −1...
Abstract Nitrogen oxide (NO x ) production by lightning in the tropics is estimated using tropospheric NO amounts (LNO *) over deep convective grid boxes derived from Ozone Monitoring Instrument (OMI) nitrogen dioxide 2 slant columns and detection‐efficiency–adjusted World Wide Lightning Location Network (WWLLN) flashes. The efficiency PE) determined for austral boreal summers of 2007 to 2011 regressing regional mean daily values LNO * individual seasons against flash totals during windows...
Abstract WRF‐Chem simulations were performed for the March 2005 East Asian Studies of Tropospheric Aerosols: an International Regional Experiment (EAST‐AIRE) Intensive Observation Campaign (IOC) to investigate direct effects aerosols on surface radiation and air quality. Domain‐wide, showed a decrease 20 W/m 2 in shortwave (SW) due aerosol effect (ADE), consistent with observational studies. The ADE caused 24 h PM 2.5 (particulate matter diameter < µm) concentrations increase eastern...
Abstract. This work describes the lightning nitric oxide (LNO) production schemes in Community Multiscale Air Quality (CMAQ) model. We first document existing LNO scheme and vertical distribution algorithm. then describe updates that were made to originally based on monthly National Lightning Detection Network (mNLDN) observations. The updated uses hourly NLDN (hNLDN) These NLDN-based are good for retrospective model applications when historical data available. For observed not available...
The very large solar proton events (SPEs) which occurred from October 19 to 27, 1989, earned substantial middle‐atmospheric HO x and NO constituent increases. Although no measurements of increases were made during these SPEs, in observed by rocket instruments are good agreement with calculated our energy degradation code. Both the can cause ozone decreases; however, ‐induced changes relatively short‐lived because species have lifetimes only hours middle atmosphere. Our two‐dimensional model,...
Outflow of CO from Asia during March 2001 is evaluated using data the Transport and Chemical Evolution over Pacific (TRACE‐P) mission Measurements Pollution in Troposphere (MOPITT) instrument conjunction with model‐calculated University Maryland chemistry transport model (UMD CTM). Comparison aircraft measurements indicates that temporal spatial variations are well captured by (mean correlation coefficient 0.78); however, mixing ratios lower than observed especially for pressures >850 hPa...
The application of van Leer's scheme, a monotonic, upstream-biased differencing to three-dimensional constituent transport calculations is shown. major disadvantage the scheme shown be self-limiting diffusion. A advantage its ability maintain correlations. adapted for spherical coordinate system with hybrid sigma-pressure in vertical. Special consideration given cross-polar flow. vertical wind calculation extremely sensitive method calculating divergence. This sensitivity implies that...
Abstract We examine wet scavenging of soluble trace gases in storms observed during the Deep Convective Clouds and Chemistry (DC3) field campaign. conduct high‐resolution simulations with Weather Research Forecasting model (WRF‐Chem) a severe storm Oklahoma. The represents well location, size, structure as compared Next Generation Radar reflectivity, simulated CO transport is consistent aircraft observations. Scavenging efficiencies (SEs) between inflow outflow species are calculated from...
This study assesses the impact of lightning nitric oxide (LNO) production schemes in Community Multiscale Air Quality (CMAQ) model on ground-level air quality as well aloft atmospheric chemistry through detailed evaluation predictions nitrogen oxides (NO x ) and ozone (O3) with corresponding observations for US. For evaluations, hourly O3 NO values from U.S. EPA System (AQS) monitoring network are used to assess different LNO prediction these species time space. Vertical evaluations...