Misa Ishizawa
A5020299074- Atmospheric and Environmental Gas Dynamics
- Atmospheric chemistry and aerosols
- Atmospheric Ozone and Climate
- Climate variability and models
- Methane Hydrates and Related Phenomena
- Hydrocarbon exploration and reservoir analysis
- Meteorological Phenomena and Simulations
- Arctic and Antarctic ice dynamics
- Marine and coastal ecosystems
- Plant Water Relations and Carbon Dynamics
- Carbon Dioxide Capture Technologies
- Global Energy and Sustainability Research
- Environmental Impact and Sustainability
- Geophysics and Gravity Measurements
- Air Quality Monitoring and Forecasting
- Ocean Acidification Effects and Responses
- Climate Change Policy and Economics
- Groundwater and Isotope Geochemistry
- Peatlands and Wetlands Ecology
- Climate change and permafrost
- Catalysis and Oxidation Reactions
- Fire effects on ecosystems
- Geomagnetism and Paleomagnetism Studies
- Cryospheric studies and observations
- Petroleum Processing and Analysis
University of Toronto
2006-2024
Environment and Climate Change Canada
2006-2024
National Institute for Environmental Studies
2014-2021
Japan Agency for Marine-Earth Science and Technology
2005
Institute for Global Environmental Strategies
2002-2004
Tohoku University
1997
Abstract. Understanding and quantifying the global methane (CH4) budget is important for assessing realistic pathways to mitigate climate change. Atmospheric emissions concentrations of CH4 continue increase, making second most human-influenced greenhouse gas in terms forcing, after carbon dioxide (CO2). The relative importance compared CO2 depends on its shorter atmospheric lifetime, stronger warming potential, variations growth rate over past decade, causes which are still debated. Two...
Abstract. The global methane (CH4) budget is becoming an increasingly important component for managing realistic pathways to mitigate climate change. This relevance, due a shorter atmospheric lifetime and stronger warming potential than carbon dioxide, challenged by the still unexplained changes of CH4 over past decade. Emissions concentrations are continuing increase, making second most human-induced greenhouse gas after dioxide. Two major difficulties in reducing uncertainties come from...
Sunlit and shaded leaf separation proposed by Norman (1982) is an effective way to upscale from canopy in modeling vegetation photosynthesis. The Boreal Ecosystem Productivity Simulator (BEPS) makes use of this methodology, has been shown be reliable the gross primary productivity (GPP) derived CO 2 flux tree ring measurements. In study, we BEPS investigate effect architecture on global distribution GPP. For purpose, not only area index (LAI) but also first ever map foliage clumping...
The ongoing development of the Global Carbon Project (GCP) global methane (CH4 ) budget shows a continuation increasing CH4 emissions and accumulation in atmosphere during 2000-2017. Here, we decompose into 19 regions (18 land 1 oceanic) five key source sectors to spatially attribute observed trends. A comparison top-down (TD) (atmospheric transport model-based) bottom-up (BU) (inventory- process emission estimates demonstrates robust temporal trends with 16 regions. Five regions-China,...
Arctic regional climate is influenced by the radiative impact of aerosol black carbon (BC) both in atmosphere and deposited on snow ice covered surfaces. The NIES (National Institute for Environmental Studies) global atmospheric transport model was used, with BC emissions from mid‐latitude fossil fuel biomass burning source regions, to simulate concentrations 16 year period. model‐simulated agreed well observations, including trends seasonality, at three sites: Alert (Nunavut, Canada),...
Abstract. We describe an assimilation system for atmospheric methane (CH4), CarbonTracker-CH4, and demonstrate the diagnostic value of global or zonally averaged CH4 abundances evaluating results. show that CarbonTracker-CH4 is able to simulate observed zonal average mole fractions capture inter-annual variability in emissions quite well at high northern latitudes (53–90° N). In contrast, less successful tropics where there are few observations therefore misses significant more influenced by...
Abstract. Following the recent Global Carbon Project (GCP) synthesis of decadal methane (CH4) budget over 2000–2012 (Saunois et al., 2016), we analyse here same dataset with a focus on quasi-decadal and inter-annual variability in CH4 emissions. The GCP integrates results from top-down studies (exploiting atmospheric observations within an inverse-modelling framework) bottom-up models (including process-based for estimating land surface emissions chemistry), inventories anthropogenic...
The recent decline in sea ice cover the Arctic Ocean could affect regional radiative forcing via changes ice–atmosphere exchange of dimethyl sulfide (DMS) and biogenic aerosols formed from its atmospheric oxidation, such as methanesulfonic acid (MSA). This study examines relationships between total extent north 70°N MSA measurement at Alert, Nunavut, during 1980–2009; Barrow, Alaska, 1997–2008; Ny‐Ålesund, Svalbard, for 1991–2004. During 1980–1989 1990–1997 periods, summer (July–August) June...
Abstract Increasing atmospheric carbon dioxide (CO 2 ) is the principal driver of anthropogenic climate change. Asia an important region for global budget, with 4 world’s 10 largest national emitters CO . Using ensemble seven inverse systems, we estimated land biosphere fluxes (natural, land-use change and fires) based on observations concentration. The Asian was a net sink −0.46 (−0.70–0.24) PgC per year (median range) 1996–2012 mostly located in East Asia, while South Southeast close to...
The provinces of Alberta and Saskatchewan account for 70% Canada's methane emissions from the oil gas sector. In 2018, Government Canada introduced regulations to reduce sector by 40–45% 2012 levels 2025. Complementary inventory accounting methods, effectiveness regulatory practices can be assessed using atmospheric measurements inverse models. Total anthropogenic (oil gas, agriculture, waste) emission rates 2010 2017 in were derived hourly over a six-month winter period October March....
Abstract The recent rise in atmospheric methane (CH 4 ) concentrations accelerates climate change and offsets mitigation efforts. Although wetlands are the largest natural CH source, estimates of global wetland emissions vary widely among approaches taken by bottom‐up (BU) process‐based biogeochemical models top‐down (TD) inversion methods. Here, we integrate situ measurements, multi‐model ensembles, a machine learning upscaling product into International Land Model Benchmarking system to...
Digital filtering and harmonic regression curve fitting techniques are applied to CO2 flask data from four stations in North America (Pt. Barrow, Alert, Sable Island Cape St. James) evaluate these two different methodologies terms of growth rate seasonal cycle the atmospheric concentration. Both methods agree relatively well producing long-term trend at each monitoring stations, as capturing large interannual variations annual rate. Furthermore, they both indicating dependency variation...
A Time‐dependent inverse (TDI) model is used to estimate carbon dioxide (CO 2 ) fluxes for 64 regions of the globe from atmospheric measurements in period January 1994 December 2001. The global land anomalies agree fairly well with earlier results. Large variability CO are recorded regions, which typically controlled by available water photosynthesis, and air temperature soil moisture dependent heterotrophic respiration. For example, anomalous emissions during 1997/1998 El Niño estimated be...
The atmosphere‐land‐ocean fluxes of CO 2 were derived for 64 partitioned areas the globe (22 over ocean and 42 land) using a time‐dependent inverse (TDI) model period January 1988 to December 2001. calculation partially follow TransCom‐3 protocol, is constrained by atmospheric concentration data from 87 stations fully transport simulations. air‐to‐land air‐to‐sea averaged 1990s are estimated at 1.15 ± 0.74 1.88 0.53 Pg‐C yr −1 , respectively. These estimates, however, remain uncertain owing...
Abstract Recent studies have proposed significant increases in CH 4 emissions possibly from oil and gas (O&G) production, especially for the U.S. where O&G production has reached historically high levels over past decade. In this study, we show that an ensemble of time‐dependent atmospheric inversions constrained by calibrated observations surface mole fraction, with some including space‐based retrievals column average fractions, suggests North American been flat years spanning 2000...
Northern Eurasia is one of the largest terrestrial carbon reservoirs on Earth's surface. However, since coverage surface CO2 observations still limited, response to climate variability remains uncertain. We estimated monthly fluxes for three sub-regions in (north ∼60°N), Northeastern Europe, Western Siberia and Eastern Siberia, using retrievals from Japanese Greenhouse Gases Observing SATellite (GOSAT). The variations were examined terms regional variability, consecutive growing seasons...
A nested inverse modelling system was developed for estimating carbon fluxes of 30 regions in North America and 20 the rest globe. Monthly conducted using CO2 concentration measurements 3 yr (2001–2003) at 88 sites. Inversion results show that 2003 global sink is -2.76 ± 0.55 Pg C. Oceans lands are responsible 88.5% 11.5% sink, respectively. Northern largest sinks with contributing a -0.97 0.21 C 2003, which Canada's -0.34 0.14 C.For Canada, spatial pattern agreement, most part, source...
Abstract. Understanding and quantifying the global methane (CH4) budget is important for assessing realistic pathways to mitigate climate change. Atmospheric emissions concentrations of CH4 are continuing increase, making second most human-influenced greenhouse gas in terms forcing, after carbon dioxide (CO2). Assessing relative importance comparison CO2 complicated by its shorter atmospheric lifetime, stronger warming potential, growth rate variations over past decade, causes which still...
Independent verification of bottom-up greenhouse gas (GHG) emission inventories is crucial for a reliable reporting Kyoto gases to the United Nations Framework Convention on Climate Change. Here, we use pseudo-data experiment test if our improved version well-known Radon tracer method (RTM) able quantitatively retrieve regional GHG fluxes. Using in-situ observations in Egbert, Canada, from 2006 2009 RTM, derive night-time fluxes CH4 and N2O southern Ontario. The found have inter-quartile...
The rate of increase in global atmospheric methane (CH 4 ) abundance has steadily declined since the late 1980s with near zero from 1999 through 2006. At Canadian Baseline Observatory at Alert, Canada (82°28′N, 62°30′W), continuous measurements and carbon dioxide (CO 2 have been made 1987. During winter, both gases are frequently highly correlated during well‐defined episodes lasting to 5 days. We observe a gradual decrease ratios CH /CO these ∼16 ppb (ppm CO −1 ∼12 over entire record. An...
Abstract. The global methane (CH4) budget is becoming an increasingly important component for managing realistic pathways to mitigate climate change. This relevance, due a shorter atmospheric lifetime and stronger warming potential than carbon dioxide, challenged by the still unexplained changes of CH4 over past decade. Emissions concentrations are continuing increase making second most human-induced greenhouse gas after dioxide. Two major difficulties in reducing uncertainties come from...
In atmospheric transport models, the covariation of and annually neutral biospheric CO 2 flux is usually evident as annual zonal mean surface concentration gradient. Using NIES model from Biome‐BGC model, covariations different mechanisms were examined quantified. Including total (processes included in model) flux, average pole to gradient 3.5 ppm interhemispheric difference extratropical 2.5 ppm. The conventional mechanism seasonal variation planetary boundary layer mixing height accounts...
We present an assimilation system for atmospheric carbon dioxide (CO2) using a Global Eulerian–Lagrangian Coupled Atmospheric model (GELCA), and demonstrate its capability to capture the observed CO2 mixing ratios estimate fluxes. With efficient data handling scheme in GELCA, our assimilates non-smoothed from observational products such as Observation Package (ObsPack) constraints on surface conducted sensitivity tests examine impact of site selections prior uncertainty settings observation...
Abstract. The Canadian Arctic (> 60∘ N, 60–141∘ W) may undergo drastic changes if the warming trend continues. For methane (CH4), reservoirs are large and widespread, climate feedbacks from such be potentially substantial. Current bottom-up top-down estimates of regional CH4 flux range widely. This study analyzes recent observations atmospheric five arctic monitoring sites presents fluxes for 2012–2015. observational data reveal sizeable synoptic summertime enhancements in that...
Abstract Estimating accurate oil and gas methane emissions has been a global challenge, highlighted by twofold discrepancy between atmospheric measurement-based estimates emission inventories. The principle of continuous improvement in Canada’s National Inventory Report led to an unstable baseline recent years for tracking reduction progress. gaps previous inventory inversions exceeded 60%. Here we show that incorporating new source-resolved information derived from low-altitude aerial...