A5012509398- Atmospheric and Environmental Gas Dynamics
- Climate variability and models
- Atmospheric Ozone and Climate
- Atmospheric chemistry and aerosols
- Meteorological Phenomena and Simulations
- Hydrocarbon exploration and reservoir analysis
- Methane Hydrates and Related Phenomena
- Cryospheric studies and observations
- Air Quality Monitoring and Forecasting
- Climate change and permafrost
- Carbon Dioxide Capture Technologies
- Spectroscopy and Laser Applications
- Geochemistry and Geologic Mapping
- Fire effects on ecosystems
- Environmental Impact and Sustainability
- Plant Water Relations and Carbon Dynamics
- Climate Change Policy and Economics
- Cardiac Imaging and Diagnostics
- Astro and Planetary Science
- Cardiovascular Function and Risk Factors
- CO2 Sequestration and Geologic Interactions
- Geophysics and Gravity Measurements
- Air Quality and Health Impacts
- Hydrology and Drought Analysis
- Reservoir Engineering and Simulation Methods
Jet Propulsion Laboratory
2019-2025
Environment and Climate Change Canada
2023
University of Toronto
2014-2021
California Institute of Technology
2021
Earth Island Institute
2021
Columbia University
2021
United States Marine Corps
2021
University of Victoria
2013-2015
Abstract. Accurate accounting of emissions and removals CO2 is critical for the planning verification emission reduction targets in support Paris Agreement. Here, we present a pilot dataset country-specific net carbon exchange (NCE; fossil plus terrestrial ecosystem fluxes) stock changes aimed at informing countries' budgets. These estimates are based on “top-down” NCE outputs from v10 Orbiting Carbon Observatory (OCO-2) modeling intercomparison project (MIP), wherein an ensemble inverse...
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 The 2023 Canadian forest fires have been extreme in scale and intensity with more than seven times the average annual area burned compared to previous four decades 1 . Here, we quantify carbon emissions from these May September on basis of inverse modelling satellite monoxide observations. We find that magnitude is 647 TgC (570–727 TgC), comparable fossil fuel large nations, only India, China USA releasing per year 2 widespread hot–dry weather was a principal driver fire spread,...
Abstract 2019 was the hottest and driest year on record for southeast Australia leading to bushfires of unprecedented extent. Ecosystem carbon losses due drought fire are believed have been substantial, but not well quantified. Here, we utilize space‐based measurements trace gases (TROPOspheric Monitoring Instrument X CO , Orbiting Carbon Observatory 2 ) up‐scaled GPP (FluxSat GPP) quantify cycle anomalies resulting from in during 2019–2020 growing season. We find that biomass burning...
Abstract. We use optimal estimation (OE) to quantify methane fluxes based on total column CH4 data from the Greenhouse Gases Observing Satellite (GOSAT) and GEOS-Chem global chemistry transport model. then project these emissions by sector at 1∘ resolution each country using a new Bayesian algorithm that accounts for prior posterior uncertainties in emissions. These estimates are intended as pilot dataset stock take support of Paris Agreement. However, differences between reported here...
Abstract. Knowledge of surface pressure is essential for calculating column-averaged dry-air mole fractions trace gases, such as CO2 (XCO2). In the NASA Orbiting Carbon Observatory 2 (OCO-2) Atmospheric Observations from Space (ACOS) retrieval algorithm, retrieved pressures have been found to unacceptable errors, warranting a parametric bias correction. This correction depends on difference between and priori pressures, which are derived meteorological model that hypsometrically adjusted...
Abstract Flash droughts– the rapid drying of land and intensification drought conditions—have devasting impacts to natural resources, food supplies, economy. Less is currently known about drivers flash droughts their impact on landscape carbon losses. We leverage water cycle data from NASA OCO‐2 Soil Moisture Active Passive missions quantify U.S. exchange. On average, pre‐onset uptake fully offsets post‐onset losses, creating a neutral biosphere over ±3 month period surrounding onset. This...
Abstract. In this study, we provide an update on the methodology and data used by Deng et al. (2022) to compare national greenhouse gas inventories (NGHGIs) atmospheric inversion model ensembles contributed international research teams coordinated Global Carbon Project. The comparison framework uses transparent processing of net ecosystem exchange fluxes carbon dioxide (CO2) from inversions estimates terrestrial stock changes over managed land that can be evaluate NGHGIs. For methane (CH4),...
We present new calculations of radiative forcing at very high concentrations CO 2 , CH 4 and N O, relevant to extreme anthropogenic climate change paleoclimate studies. is calculated over the range 100 ppmv 50,000 ppmv, maximum 38.1 W m −2 . O forcings are ppbv give 6.66 22.3 The sensitivity our spatial averaging tropopause definition examined. compare results with “simplified expressions” reported by Intergovernmental Panel on Climate Change (IPCC) find significant differences greenhouse...
Abstract While large‐scale floods directly impact human lives and infrastructures, they also profoundly agricultural productivity. New satellite observations of vegetation activity atmospheric CO 2 offer the opportunity to quantify effects such extreme events on cropland carbon sequestration. Widespread flooding during spring early summer 2019 induced conditions that delayed crop planting across U.S. Midwest. As a result, solar‐induced chlorophyll fluorescence from TROPOspheric Monitoring...
Abstract Top‐down estimates of CO 2 fluxes are typically constrained by either surface‐based or space‐based observations. Both these measurement types have spatial and temporal gaps in observational coverage that can lead to differences inferred fluxes. Assimilating both measurements concurrently a flux inversion framework improves reduces sampling related artifacts. This study examines the consistency constraints provided different observations potential combine them performing series...
Abstract The European land carbon uptake has been heavily impacted by several recent severe droughts, yet quantitative estimates of anomalies are uncertain. Atmospheric CO 2 inverse models (AIMs) provide observation‐based the large‐scale flux dynamics, but how well they capture drought impacts on terrestrial is poorly known. Here we assessed capacity state‐of‐the‐art AIMs in monitoring over 2001–2015 using observations environmental variability and vegetation function made comparisons with...
Abstract. In this study, we provide an update of the methodology and data used by Deng et al. (2022) to compare national greenhouse gas inventories (NGHGIs) atmospheric inversion model ensembles contributed international research teams coordinated Global Carbon Project. The comparison framework uses transparent processing net ecosystem exchange fluxes carbon dioxide (CO2) from inversions estimates terrestrial stock changes over managed land that can be evaluate NGHGIs. For methane (CH4),...
Abstract Inverse modeling of regional CO 2 fluxes using atmospheric data is sensitive to the observational coverage observing network. Here we use GEOS‐Chem adjoint model examine sensitivity observations from in situ surface network, Total Carbon Column Observing Network (TCCON), Greenhouse Gases Satellite (GOSAT), and Orbiting Observatory (OCO‐2). We find that OCO‐2 has high throughout tropics Southern Hemisphere, while have northern extratropics year. For GOSAT viewing modes, ocean glint...
Abstract The 2015 Paris Climate Agreement and Global Methane Pledge formalized agreement for countries to report reduce methane emissions mitigate near‐term climate change. Emission inventories generated through surface activity measurements are reported annually or bi‐annually, evaluated periodically a “Global Stocktake.” Emissions inverted from atmospheric data support evaluation of inventories, but their systematic use is stifled by spatially variable biases prior errors combined with...
Across temperate North America, interannual variability (IAV) in gross primary production (GPP) and net ecosystem exchange (NEE) their relationship with environmental drivers are poorly understood. Here, we examine IAV GPP NEE to using two state-of-the-science flux products: constrained by surface space-based atmospheric CO
Abstract. Site-level observations have shown pervasive cold season CO2 release across Arctic and boreal ecosystems, impacting annual carbon budgets. Still, the seasonality of emissions are poorly quantified much high latitudes due to sparse coverage site-level observations. Space-based provide opportunity fill some observational gaps for studying these high-latitude particularly sampled regions Eurasia. Here, we show that data-driven net ecosystem exchange (NEE) from atmospheric implies...
Abstract The magnitude and distribution of China's terrestrial carbon sink remain uncertain due to insufficient constraints at large scales, whereby satellite data offer great potential for reducing the uncertainty. Here, we present two estimates China constrained either by CO 2 column concentrations (XCO ) within Global Carbon Assimilation System or remotely sensed soil moisture Fraction Absorbed Photosynthetically Active Radiation (FAPAR) in addition situ observations Cycle Data System....
Abstract. Inverse model intercomparison projects (MIPs) provide a chance to assess the uncertainties in inversion estimates arising from various sources. However, accurately quantifying ensemble CO2 flux errors remains challenging and often relies on spread. This study proposes method for regional net surface–atmosphere models taken Orbiting Carbon Observatory-2 (OCO-2) v10 MIP by using independent airborne measurements period 2015–2017. We first calculate root mean square error (RMSE)...
Abstract Accurate accounting of greenhouse‐gas (GHG) emissions and removals is central to tracking progress toward climate mitigation for monitoring potential climate‐change feedbacks. GHG budgeting reporting can follow either the Intergovernmental Panel on Climate Change methodologies National Greenhouse Gas Inventory (NGHGI) or use atmospheric‐based “top‐down” (TD) inversions process‐based “bottom‐up” (BU) approaches. To help understand reconcile these approaches, Second REgional Carbon...
Abstract. Despite reduced insolation in the late Archean, evidence suggests a~warm climate which was likely sustained by a stronger greenhouse effect, so-called faint young sun problem (FYSP). CO2 and CH4 are generally thought to be mainstays of this enhanced greenhouse, though many other gases have been proposed. We present high accuracy radiative forcings for CO2, CH4, 26 gases, performing transfer calculations at line-by-line resolution using HITRAN 2012 line data background pressures...
Abstract On regional to global scales, few constraints exist on gross primary productivity (GPP) and ecosystem respiration ( R e ) fluxes. Yet these fluxes are critical for evaluating improving terrestrial biosphere models. In this study, we evaluate the seasonal cycle of GPP, , net exchange (NEE) produced by four models FLUXCOM, a data‐driven model, over northern midlatitude ecosystems. We GPP NEE using solar‐induced fluorescence retrieved from Global Ozone Monitoring Experiment‐2...