A5064833315- Atmospheric chemistry and aerosols
- Atmospheric and Environmental Gas Dynamics
- Marine and coastal ecosystems
- Atmospheric Ozone and Climate
- Geology and Paleoclimatology Research
- Cryospheric studies and observations
- Isotope Analysis in Ecology
- Air Quality Monitoring and Forecasting
- Odor and Emission Control Technologies
- Atmospheric aerosols and clouds
- Ocean Acidification Effects and Responses
- Oceanographic and Atmospheric Processes
- Methane Hydrates and Related Phenomena
- Air Quality and Health Impacts
- Polar Research and Ecology
- Climate variability and models
- Toxic Organic Pollutants Impact
- Mercury impact and mitigation studies
- Ocean Waves and Remote Sensing
- Fire effects on ecosystems
- Water Quality Monitoring and Analysis
- Arctic and Antarctic ice dynamics
- Hydrocarbon exploration and reservoir analysis
- Maritime Transport Emissions and Efficiency
- Meteorological Phenomena and Simulations
University of California, Irvine
2016-2025
Irvine University
2011-2022
National Institute of Water and Atmospheric Research
2016
The University of Texas at Austin
2008
Droplet Measurement Technologies (United States)
2007
University of Wisconsin–Milwaukee
2007
University of Miami
1991-2004
Miami University
1982-2000
U.S. National Science Foundation
1999
NOAA Pacific Marine Environmental Laboratory
1993-1998
[1] The potentially significant role of the biogenic trace gas dimethylsulfide (DMS) in determining Earth's radiation budget makes it necessary to accurately reproduce seawater DMS distribution and quantify its global flux across sea/air interface. Following a threefold increase data (from 15,000 over 47,000) surface ocean database last decade, new monthly climatologies concentration sea-to-air emission are presented as updates those constructed 10 years ago. Interpolation/extrapolation...
The aerodynamic friction between air and sea is an important part of the momentum balance in development tropical cyclones. Measurements drag coefficient, relating tangential stress (frictional drag) wind water to speed density, have yielded reliable information speeds less than 20 m/s (about 39 knots). In these moderate conditions it generally accepted that coefficient (or equivalently, “aerodynamic roughness”) increases with speed. Can one merely extrapolate this tendency describe...
Black carbon (BC) from biomass and fossil fuel combustion alters chemical physical properties of the atmosphere snow albedo, yet little is known about its emission or deposition histories. Measurements BC, vanillic acid, non-sea-salt sulfur in ice cores indicate that sources concentrations BC Greenland precipitation varied greatly since 1788 as a result boreal forest fires industrial activities. Beginning 1850, emissions resulted sevenfold increase ice-core concentrations, with most change...
Biogenic sources contribute to cloud condensation nuclei (CCN) in the clean marine atmosphere, but few measurements exist constrain climate model simulations of their importance. The chemical composition individual atmospheric aerosol particles showed two types sulfate-containing air masses addition mass-based Estimated Salt particles. Both sulfate lack combustion tracers and correlate, for some conditions, or seawater dimethyl sulfide (DMS) concentrations, which means source was largely...
The North Atlantic Aerosols and Marine Ecosystems Study (NAAMES) is an interdisciplinary investigation to improve understanding of Earth's ocean ecosystem-aerosol-cloud system. Specific overarching science objectives for NAAMES are (1) characterize plankton ecosystem properties during primary phases the annual cycle their dependence on environmental forcings, (2) determine how these interact recreate each year conditions bloom, (3) resolve remote marine aerosols boundary layer clouds...
Abstract. For the past decade, observations of carbonyl sulfide (OCS or COS) have been investigated as a proxy for carbon uptake by plants. OCS is destroyed enzymes that interact with CO2 during photosynthesis, namely carbonic anhydrase (CA) and RuBisCO, where CA more important one. The majority sources to atmosphere are geographically separated from this large plant sink, whereas sinks co-located in ecosystems. drawdown can therefore be related without added complication emissions...
Estimates of the sea‐to‐air flux dimethylsulfide (DMS) are based on sea surface concentration measurements and gas exchange calculations. Such calculations dependent diffusivity DMS (D ), which has never been experimentally determined. In this study in pure water was measured over a temperature range 5°–30°C. The were made using dynamic diffusion cell diffusing flows one side an agar gel membrane inert other side. coefficient can be estimated from either time or steady state analysis data,...
Methane sulfonic acid (MSA) is an oxidation product of the reaction OH radical with dimethyl sulfide and, hence, should be important constituent marine air. MSA concentrations in aerosols ranged from 0.009 to 0.075 μg/m 3 samples Pacific and Indian oceans Miami, Florida. In remote areas (Pacific oceans), levels averaged 6.7% ( S = 1.9) non‐sea‐salt (nss) SO 4 . Miami area, ratios were occasionally lower because impact local sulfur emissions (probably pollutant 2 ). seven rainwater collected...
The goals of the International Global Atmospheric Chemistry (IGAC) Program's First Aerosol Characterization Experiment (ACE 1) are to determine and understand properties controlling factors aerosol in remote marine atmosphere that relevant radiative forcing climate. A key question terms this goal overall biogeochemical sulfur cycle is what control formation, growth, evolution particles boundary layer (MBL). To address question, simultaneous measurements dimethylsulfide (DMS), dioxide (SO 2...
Abstract. Fluorescence Assay by Gas Expansion (FAGE) has been used to detect ambient levels of OH and HO2 radicals at the Cape Verde Atmospheric Observatory, located in tropical Atlantic marine boundary layer, during May June 2007. Midday radical concentrations were high, with maximum 9 ×106 molecule cm−3 6×108 observed for HO2, respectively. A box model incorporating detailed Master Chemical Mechanism, extended include halogen chemistry, heterogeneous loss processes constrained all...
From mid‐May 1984 through December 1987, more than 1100 daily high‐volume bulk aerosol samples were collected during onshore trade winds at Barbados, West Indies. All of these have been analyzed to determine the concentrations particulate non‐sea‐salt (nss) sulfate, nitrate, and Saharan dust; 91 also for methanesulfonate (MSA). The mean (in μg m −3 ) period 0.509 (s = 0.389); nss 0.751 0.602); mineral dust, 16.0 21.1); MSA, 0.0207 0.0093). both nitrate sulfate are significantly correlated...
Abstract. Cl atoms in the marine atmosphere may significantly impact lifetimes of methane and other hydrocarbons. However, existing estimates atom levels air are based on indirect evidence. Here we present measurements precursors HOCl Cl2 boundary layer during June 2009 at Cape Verde Atmospheric Observatory eastern tropical Atlantic. These first tropospheric HOCl. were low with open ocean back trajectories, maximum always below 60 10 ppt (pmol/mol), respectively. In trajectories originating...
Significance Cold and dry glacial-state climate conditions persisted in the Southern Hemisphere until approximately 17.7 ka, when paleoclimate records show a largely unexplained sharp, nearly synchronous acceleration deglaciation. Detailed measurements Antarctic ice cores document exactly at that time unique, ∼192-y series of massive halogen-rich volcanic eruptions geochemically attributed to Mount Takahe West Antarctica. Rather than coincidence, we postulate halogen-catalyzed stratospheric...
Abstract. Shipboard measurements of eddy covariance dimethylsulfide (DMS) air–sea fluxes and seawater concentration were carried out in the North Atlantic bloom region June/July 2011. Gas transfer coefficients (k660) show a linear dependence on mean horizontal wind speed at speeds up to 11 m s−1. At higher relationship between k660 weakens. high winds, measured DMS lower than predicted based interfacial stress extrapolated from low intermediate speeds. In contrast, coefficient for sensible...
Abstract This study uncovers an early 1990s change in the relationships between El Niño–Southern Oscillation (ENSO) and two leading modes of Southern Hemisphere (SH) atmospheric variability: southern annular mode (SAM) Pacific–South American (PSA) pattern. During austral spring, while PSA maintained a strong correlation with ENSO throughout period 1948–2014, SAM–ENSO changed from being weak before to afterward. Through connection, SAM became more in-phase correlated after 1990s. The is also...
Abstract. Marine dimethyl sulfide (DMS) is important to climate due the ability of DMS alter Earth's radiation budget. Knowledge global-scale distribution, seasonal variability, and sea-to-air flux needed in order improve understanding atmospheric sulfur, aerosol/cloud dynamics, albedo. Here we examine use an artificial neural network (ANN) extrapolate available measurements global ocean produce a climatology with monthly temporal resolution. A database 82 996 ship-based surface waters was...
Abstract The majority of the aerosol particle number (condensation nuclei or CN) in marine boundary layer (MBL) consists sulfate and organic compounds that have been shown to provide a large fraction cloud condensation (CCN). Here we use submicron non‐refractory Aerosol Mass Spectrometer (AMS) filter measurements components particles measured during four North Atlantic Marine Ecosystems Study (NAAMES) research cruises assess sources contributions for CCN concentrations MBL different seasons....