Dr. Matthew Johnson is a civil servant Research Scientist in the Earth Science Division at NASA Ames Research Center.  His research interest include: 1) analyzing global/regional source apportioned greenhouse gas emissions and atmospheric concentrations using “bottom-up” and “top-down” modeling techniques, 2) combining remotely-sensed, modeling, and in situ data to evaluate aerosol and trace gas emissions, transport, chemical transformation, and deposition, and 3) modeling of mineral dust and bioavailable nutrient (e.g., iron, phosphorus, nitrogen) deposition to the world’s oceans.
____________________________________________________________________________________

Recent Research Highlights

• PI on a NASA Interdisciplinary Research in Earth Science (IDS) study titled "What is the role of natural wetlands, lakes and reservoirs in the contemporary global methane cycle? Integrating new approaches to source characterization, observation-anchored models, and CarbonTracker-CH4 assessments".
• Evaluating forward and inverse modeling of global biospheric CO₂ fluxes. This work will focus on 1) the ability to evaluate and constrain global biospheric CO₂ fluxes with OCO-2 data and 2) the importance of prior model predictions on inverse model calculations of biospheric CO₂ flux estimates.
• Member of NASA's TOLNet Science Team
  • Publication in AMT evaluating the impact of varying a priori ozone profile sources on TEMPO retrievals of tropospheric ozone
  • Publication in GRL investigating the impact of the NA monsoon on tropospheric ozone.
  • Publication in Atmosphere focused on sources of ozone in the southeast US.
  • Publication in Atmospheric Environment evaluating sources of ozone lamina over California.
• Investigating the impact of mineral dust and bioavailable nutrient deposition on marine biogeochemical cycling.
  • Publication in Aeolian Research evaluating the impact of measurement uncertainties on our understanding of soluble iron concentrations
  • Publication in Nature Geoscience investigating the impact of anthropogenic emissions on bioavailable nutrient deposition and oceanic oxygen levels
  • Publication in Marine Chemistry evaluating the potential impact of atmospheric organic ligands on nutrient bioavailability in oceanic environments
• Implemented on-line marine organic aerosol emissions into the newest version of the regional/global scale 3-D chemical transport model GEOS-Chem.
  • Publication in Geosci. Model Dev.
  • This emission scheme was voted at the 7th International GEOS-Chem Meeting to be included in all future public versions of the GEOS-Chem model.
• Applying inverse modeling techniques to constrain greenhouse gas and volcanic emission inventories using airborne measurement data (i.e., aircraft and unmanned aerial systems (UASs)).
  • Manuscript investigating seasonal methane emissions in California published in the Journal of Geophysical Research: Atmospheres.
  • Publication calculating degassing volcanic SO₂ emission rates in the Journal of Volcanology and Geothermal Research.