A5026006002- Atmospheric and Environmental Gas Dynamics
- Atmospheric chemistry and aerosols
- Climate change and permafrost
- Air Quality and Health Impacts
- Cryospheric studies and observations
- Air Quality Monitoring and Forecasting
- Atmospheric Ozone and Climate
- Methane Hydrates and Related Phenomena
- Plant responses to elevated CO2
- Peatlands and Wetlands Ecology
- Vehicle emissions and performance
- COVID-19 impact on air quality
- Climate Change and Health Impacts
- Hydrocarbon exploration and reservoir analysis
- Ionosphere and magnetosphere dynamics
- Climate variability and models
- Geological Studies and Exploration
- Radiomics and Machine Learning in Medical Imaging
- Odor and Emission Control Technologies
- Global Energy and Sustainability Research
- Global Energy Security and Policy
- Climate Change Policy and Economics
- Agricultural Development and Policies
- Oceanographic and Atmospheric Processes
- Winter Sports Injuries and Performance
Lamont-Doherty Earth Observatory
2016-2024
Columbia University
2018-2024
Harvard University
2021-2023
Massachusetts Institute of Technology
2014-2019
University of Wisconsin System
2010
Arctic-boreal landscapes are experiencing profound warming, along with changes in ecosystem moisture status and disturbance from fire. This region is of global importance terms carbon feedbacks to climate, yet the sign (sink or source) magnitude budget within recent years remains highly uncertain. Here, we provide new estimates (2003-2015) vegetation gross primary productivity (GPP), respiration (Reco ), net CO2 exchange (NEE; Reco - GPP), terrestrial methane (CH4 ) emissions for zone using...
Abstract Soil respiration (i.e. from soils and roots) provides one of the largest global fluxes carbon dioxide (CO 2 ) to atmosphere is likely increase with warming, yet magnitude soil rapidly thawing Arctic-boreal regions not well understood. To address this knowledge gap, we first compiled a new CO flux database for permafrost-affected tundra boreal ecosystems in Alaska Northwest Canada. We then used database, multi-sensor satellite imagery, random forest models assess regional...
Understanding the local-scale spatial and temporal variability of ozone formation is crucial for effective mitigation. We combine tropospheric vertical column densities (VCDTrop) formaldehyde (HCHO) nitrogen dioxide (NO2), referred to as HCHO-VCDTrop NO2-VCDTrop, retrieved from airborne remote sensing TROPOspheric Monitoring Instrument (TROPOMI) with ground-based measurements investigate changes in precursors inferred chemical production regime on high-ozone days May–August 2018 over two...
Air quality policies have made substantial gains by reducing pollutant emissions from the transportation sector. In March 2020, New York City's activities were severely curtailed in response to COVID-19 pandemic, resulting 60–90% reductions human activity. We continuously measured major volatile organic compounds (VOCs) during January–April 2020 and 2021 Manhattan. Concentrations of many VOCs decreased significantly shutdown with variations daily patterns reflective activity perturbations, a...
Airborne observations from the California Research at Nexus of Air Quality and Climate Change (CalNex) campaign in May June 2010 are used to investigate role ammonia (NH3) fine particulate matter (PM2.5) formation surface air quality test key processes relevant inorganic aerosol GEOS-Chem model. Concentrations throughout California, sulfur dioxide (SO2) Central Valley, ammonium nitrate Los Angeles (LA) area underestimated several-fold We find that model concentrations relatively insensitive...
Abstract. The variability of atmospheric ammonia (NH3), emitted largely from agricultural sources, is an important factor when considering how inorganic fine particulate matter (PM2.5) concentrations and nitrogen cycling are changing over the United States. This study combines new observations concentration surface, aboard aircraft, retrieved by satellite to both evaluate simulation in a chemical transport model (GEOS-Chem) identify which processes control these 5-year period (2008–2012). We...
Abstract. Ensuring global food security requires a comprehensive understanding of environmental pressures on production, including the impacts air quality. Surface ozone damages plants and decreases crop production; this effect has been extensively studied. In contrast, presence particulate matter (PM) in atmosphere can be beneficial to crops given that enhanced light scattering leads more even efficient distribution photons which outweigh total incoming radiation loss. This study quantifies...
Abstract. Nitrogen oxides (NOx≡NO+NO2) 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 Ozone Monitoring Instrument (OMI) produced by NASA Royal Netherlands Meteorological Institute (KNMI) provide coverage to test our understanding factors controlling NOx. We find that these products offer useful information when averaged over coarse scales (20∘×32∘,...
The COVID-19 pandemic created an extreme natural experiment in which sudden changes human behavior and economic activity resulted significant declines nitrogen oxide (NO x ) emissions, immediately after strict lockdowns were imposed. Here we examined the impact of multiple waves response phases on dioxide (NO2) dynamics role meteorology shaping relative contributions from different emission sectors to NO2 pollution post-pandemic New York City. Long term (> 3.5 years), high frequency...
Abstract. Accurately quantifying methane emissions from cities and understanding the processes that drive them are important for reaching climate mitigation goals. Methane New York City metropolitan area (NYCMA), most populous urban of United States, have consistently been underestimated by emission inventories compared to aircraft satellite observations. In this study, we used continuous rooftop measurements over 6 winter-to-spring transitions (January–May, 2019–2024) examine variability...
Abstract. The continued warming of the Arctic could release vast stores carbon into atmosphere from high-latitude ecosystems, especially thawing permafrost. Increasing uptake dioxide (CO2) by vegetation during longer growing seasons may partially offset such carbon. However, evidence significant net annual site-level observations and model simulations across tundra ecosystems has been inconclusive. To address this knowledge gap, we combined top-down atmospheric CO2 concentration enhancements...
Abstract. Accurate estimates of carbon–climate feedbacks require an independent means for evaluating surface flux models at regional scales. The altitude-integrated enhancement (AIE) derived from the Arctic Carbon Atmospheric Profiles (Arctic-CAP) project demonstrates utility this bulk quantity model evaluation. This leverages background mole fraction values middle free troposphere, is agnostic to uncertainties in boundary layer height, and can be fractions vertical gradients. To demonstrate...
Abstract In the Arctic waterbodies are abundant and rapid thaw of permafrost is destabilizing carbon cycle changing hydrology. It particularly important to quantify accurately scale aquatic emissions in arctic ecosystems. Recently available high-resolution remote sensing datasets capture physical characteristics landscapes at unprecedented spatial resolution. We demonstrate how machine learning models can capitalize on these greatly improve accuracy when scaling waterbody CO 2 CH 4 fluxes...
Abstract. We measured the global distribution of tropospheric N2O mixing ratios during NASA airborne Atmospheric Tomography (ATom) mission. ATom concentrations ∼ 300 gas species and aerosol properties in 647 vertical profiles spanning Pacific, Atlantic, Arctic, much Southern Ocean basins, nearly from pole to pole, over four seasons (2016–2018). at 1 Hz using a quantum cascade laser spectrometer (QCLS). introduced new spectral retrieval method account for pressure temperature sensitivity...
Abstract. Wetlands are the largest natural source of methane (CH4) emissions globally. Northern wetlands (>45° N), accounting for 42 % global wetland area, increasingly vulnerable to carbon loss, especially as CH4 may accelerate under intensified high-latitude warming. However, magnitude and spatial patterns remain relatively uncertain. Here we present estimates daily fluxes obtained using a new machine learning-based upscaling framework (WetCH4) that applies most complete database eddy...
Abstract Cities are beginning to monitor atmospheric carbon dioxide (CO 2 ) assess the efficacy of their climate policies. However, changes in anthropogenic CO emissions must be separated from biospheric fluxes which have a large seasonal cycle. Urban vegetation (e.g. lawns, trees along street and parks, etc) developed land covers is often omitted regional biogenic flux models. We set up biosphere model estimate New York City (NYC) importance within covers. The incorporates high-resolution...
Abstract Purpose of Review While previously thought to be negligible, carbon emissions during the non-growing season (NGS) can a substantial part annual budget in Arctic boreal zone (ABZ), which shift balance these ecosystems from long-held sink towards net source. The purpose this review is summarize NGS dioxide (CO 2 ) flux research ABZ that has been published within past 5 years. Recent Findings We explore processes and magnitudes CO fluxes, status modeling efforts, evaluate future...
Abstract. Landscapes are often assumed to be homogeneous when interpreting eddy covariance fluxes, which can lead biases gap-filling and scaling up observations determine regional carbon budgets. Tundra ecosystems heterogeneous at multiple scales. Plant functional types, soil moisture, thaw depth, microtopography, for example, vary across the landscape influence net ecosystem exchange (NEE) of dioxide (CO2) methane (CH4) fluxes. With warming temperatures, Arctic changing from a sink source...
GIEMS2 represents the minimum extents of northern wetlands.**GLWD provides a representation maximum extent wetlands.***These numbers are derived from CT natural microbial emissions, which include emissions wetlands, river/lake/pond systems, and possibly wild animals (despite small amount).
Abstract An estimated 1700 Pg of carbon is frozen in the Arctic permafrost and fate this unclear because complex interaction biophysical, ecological biogeochemical processes that govern budget. Two key determining region’s long-term budget are: (a) uptake through increased plant growth, (b) release heterotrophic respiration (HR) due to warmer soils. Previous predictions for how these two opposing fluxes may change future have varied greatly, indicating improved understanding their feedbacks...
Abstract. Changing atmospheric composition, induced primarily by industrialization and climate change, can impact plant health may have implications for global food security. Atmospheric particulate matter (PM) enhance crop production through the redistribution of light from sunlight to shaded leaves. Nitrogen transported atmosphere also increase when deposited onto cropland reducing nutrient limitations in these areas. We employ a model (pDSSAT), coupled input an chemistry (GEOS-Chem),...
Abstract. The variability of atmospheric ammonia (NH3), emitted largely from agricultural sources, is an important factor when considering how inorganic fine particulate matter (PM2.5) concentrations and nitrogen cycling are changing over the United States. This study combines new observations concentration surface, aboard aircraft, retrieved by satellite to both evaluate simulation in a chemical transport model (GEOS-Chem) identify which processes control these 5-year period (2008–2012). We...