A5006664521- Atmospheric chemistry and aerosols
- Atmospheric and Environmental Gas Dynamics
- Atmospheric Ozone and Climate
- Air Quality and Health Impacts
- Air Quality Monitoring and Forecasting
- Climate variability and models
- Atmospheric aerosols and clouds
- Meteorological Phenomena and Simulations
- Marine and coastal ecosystems
- Vehicle emissions and performance
- Climate Change and Health Impacts
- Plant Water Relations and Carbon Dynamics
- Isotope Analysis in Ecology
- Groundwater and Isotope Geochemistry
- History and advancements in chemistry
- Water Quality Monitoring and Analysis
- Energy and Environment Impacts
- Health, Environment, Cognitive Aging
Columbia University
2011-2025
Lamont-Doherty Earth Observatory
2014-2023
Goddard Institute for Space Studies
2011-2015
NOAA Geophysical Fluid Dynamics Laboratory
2007
Tropospheric ozone and black carbon (BC) contribute to both degraded air quality global warming. We considered ~400 emission control measures reduce these pollutants by using current technology experience. identified 14 targeting methane BC emissions that projected mean warming ~0.5°C 2050. This strategy avoids 0.7 4.7 million annual premature deaths from outdoor pollution increases crop yields 30 135 metric tons due reductions in 2030 beyond. Benefits of are valued at $700 $5000 per ton,...
Abstract. The Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) examined the short-lived drivers of climate change in current models. Here we evaluate 10 ACCMIP models that included aerosols, 8 which also participated Coupled phase 5 (CMIP5). reproduce present-day total aerosol optical depth (AOD) relatively well, though many are biased low. Contributions from individual components quite different, however, most underestimate east Asian AOD. capture 1980–2000 AOD...
Air pollution in many of India's cities exceeds national and international standards, effective control strategies require knowledge the sources that contribute to air their spatiotemporal variability. In this study, we examine influence a single source, outdoor biomass burning, on particulate matter (PM) concentrations, surface visibility, aerosol optical depth (AOD) from 2007 2013 three most populous Indian cities. We define upwind regions, or "airsheds," for by using atmospheric back...
The formation of organic nitrates during the oxidation biogenic hydrocarbon isoprene can strongly affect boundary layer concentrations ozone and nitrogen oxides (NO x = NO + 2 ). We constrain uncertainties in chemistry these using chemical transport model simulations conjunction with observations over eastern United States from International Consortium for Atmospheric Research on Transport Transformation (ICARTT) field campaign summer 2004. best captures observed their correlation a 4% yield...
Abstract. The new generation GISS climate model includes fully interactive chemistry related to ozone in historical and future simulations, methane simulations. Evaluation of ozone, its tropospheric precursors, shows that the captures much large-scale spatial structure seen recent observations. While is improved compared with previous chemistry-climate model, especially for seasonality stratosphere, there still slightly too rapid stratospheric circulation, little stratosphere-to-troposphere...
Abstract Examination of effective radiative forcing (ERF), a measure changes in Earth's energy balance, facilitates understanding the role various drivers climate change. For short‐lived compounds, ERF can be highly inhomogeneous geographically. The relationship between spatial patterns and surface temperature response is poorly characterized, however. We examine that latest generation global models. find uneven distribution historical aerosol, ozone, land use leads to substantial...
Abstract. Precipitation shifts can have large impacts on human society and ecosystems. Many aspects of how inhomogeneous radiative forcings influence precipitation remain unclear, however. Here we investigate regional responses to various imposed in different latitude bands a climate model. We find that several regions show strong, significant most forcings, but the magnitude even sign depends upon forcing location type. Aerosol ozone typically induce larger than equivalent carbon dioxide...
Abstract. US background ozone (O3) includes O3 produced from anthropogenic precursors emitted outside of the USA, global methane, and any natural sources. Using a suite sensitivity simulations in GEOS-Chem chemistry transport model, we estimate influence individual sources versus on total surface over 10 continental regions 2004 to 2012. Evaluation with observations reveals model biases +0–19 ppb seasonal mean maximum daily 8 h average (MDA8) O3, highest summer eastern USA. Simulated high-O3...
Despite having a population of 16.3 million, Kinshasa, Democratic Republic the Congo (DRC), has had little attention toward air quality monitoring. We deployed MetOne Beta Attenuation Monitor (BAM-1020) for reference PM2.5 and QuantAQ Modulair, latter which includes measurements gas-phase NO2, O3, CO, CO2, in addition to PM1, PM2.5, PM10. Here we present first results from this aggregated, multisensor, multispecies network DRC. compare Modulair against BAM-1020, finding an r2 0.76 mean...
Abstract India is largely devoid of high‐quality and reliable on‐the‐ground measurements fine particulate matter (PM 2.5 ). Ground‐level PM concentrations are estimated from publicly available satellite Aerosol Optical Depth (AOD) products combined with other information. Prior research has overlooked the possibility gaining additional accuracy insights into sources using retrievals tropospheric trace gas columns. We evaluate information content columns for estimates over within a modeling...
Abstract. A primary goal of the Atmospheric Chemistry and Climate Model Intercomparison Project (ACCMIP) was to characterize short-lived drivers preindustrial 2100 climate change in current generation models. Here we evaluate historical future radiative forcing 10 ACCMIP models that included aerosols, 8 which also participated Coupled phase 5 (CMIP5). The generally reproduce present-day climatological total aerosol optical depth (AOD) relatively well. They have quite different contributions...
Abstract Risk assessments of air pollution impacts on human health and ecosystems would ideally consider a broad set climate emission scenarios, as well natural internal variability. We analyze initial condition chemistry‐climate ensembles to gauge the significance greenhouse‐gas‐induced changes relative variability, response differences in two models. To quantify effects change frequency duration summertime regional‐scale episodes over Eastern United States (EUS), we apply an Empirical...
The hydroxyl radical (OH) sets the oxidative capacity of atmosphere and determines lifetime reactive greenhouse gases such as methane (CH4). response OH to climate warming is influenced by uncertain compensating processes involving weather-sensitive chemistry emissions. In this study, we extend idealized aquaplanet configuration Community Earth System Model (CESM) Atmosphere version 6 (CAM6) include atmospheric (“AquaChem”).  Beyond aquaplanet’s zonally...
Abstract. Abundance-based model evaluations with observations provide critical tests for the simulated mean state in models of intercontinental pollution transport, and under certain conditions may also offer constraints on responses to emission changes. We compile multiyear measurements peroxy acetyl nitrate (PAN) available from five mountaintop sites apply them a proof-of-concept approach that exploits an ensemble global chemical transport (HTAP1) identify observational “emergent...
Abstract. The new generation GISS climate model includes fully interactive chemistry related to ozone in historical and future simulations, methane simulations. Evaluation of ozone, its tropospheric precursors, shows that the captures much large-scale spatial structure seen recent observations. While is improved compared with previous chemistry-climate model, especially for seasonality stratosphere, there still slightly too rapid stratospheric circulation little stratosphere-to-troposphere...
Abstract Ambient fine particulate matter (PM 2.5 ) concentrations in India frequently exceed 100 μg/m 3 during fall and winter pollution episodes. We use the GEOS‐Chem chemical transport model with TwO‐Moment Aerosol Sectional microphysics scheme 15 size bins (TOMAS15) to assess PM composition impacts on radiation cloud condensation nuclei (CCN) episodes as compared seasonal (October‐December) average. conduct high resolution (0.25° × 0.3125°) nested‐domain simulations over for...
Abstract. Peroxy acetyl nitrate (PAN) is the most important reservoir species for nitrogen oxides (NOx) in remote troposphere. Upon decomposition regions, PAN promotes efficient ozone production. We evaluate monthly mean abundances from global chemical transport model simulations (HTAP1) 2001 with measurements five northern mid-latitude mountain sites (four European and one North American). The multi-model generally captures observed but individual models simulate a factor of ~ 4–8 range...
Abstract. Precipitation shifts can have large impacts on human society and ecosystems. Many aspects of how inhomogeneous radiative forcings influence precipitation remain unclear, however. Here we investigate regional responses to various imposed in different latitude bands a climate model. We find that several regions show strong, significant most forcings, but the magnitude even sign depends upon forcing location type. Aerosol ozone typically induce larger than equivalent carbon dioxide...
In his comment, Laprise raises several points that we agree merit consideration. His primary critique is our study [Racherla et al., 2012] tested the ability of WRF regional climate model to reproduce historical temperature and precipitation change relative driving global (GCM) using only a single simulation rather than an ensemble. He asserts observed changes are smaller internal variability in system (i.e., not statistically significant) thus should necessarily be able capture...
Abstract. U.S. background ozone (O3) includes O3 produced from anthropogenic precursors emitted outside of the U.S.A., global methane, and any natural sources. Using a suite sensitivity simulations in GEOS-Chem chemistry-transport model, we estimate influence individual versus sources on total surface over ten continental regions 2004–2012. Evaluation with observations reveals model biases +0–19 ppb seasonal mean maximum daily 8-hour average (MDA8) O3, highest summer eastern U.S.A. Simulated...
India is largely devoid of high-quality and reliable on-the-ground measurements fine particulate matter (PM2.5). Ground-level PM2.5 concentrations are estimated from publicly available satellite Aerosol Optical Depth (AOD) products combined with other information. Prior research has overlooked the possibility gaining additional accuracy insights into sources PM using retrievals tropospheric trace gas columns. We first evaluate information content columns for estimates over within a modeling...