For questions about GMD seminars, contact Julie Singewald, Phone: (303) 497-6074

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Upcoming Seminars



Title:

Approaching Two Decades of MOPITT - What have we learned from satellite carbon monoxide observations

Speaker: Helen Worden
Dr. Helen Worden is a project scientist at the National Center for Atmospheric Research in the Atmospheric Chemistry Observations & Modeling Laboratory. She received a bachelor's degree in Physics from the University of Colorado and her PhD in Elementary Particle Physics from Cornell University. Prior to moving back to Boulder, Dr. Worden was at the NASA Jet Propulsion Laboratory in Pasadena, CA, where she worked on the NASA Aura Tropospheric Emission Spectrometer. Since 2016, she has been the U.S. Principal Investigator for the MOPITT instrument on the NASA Terra satellite.
Date/Time: Tuesday, September 24, 2019 11:00 AM
Location: David Skaggs Research Center, GC402 (multi-purpose room)
Abstract
Measurements Of Pollution In The Troposphere (MOPITT) on the NASA Terra spacecraft has been measuring the global atmospheric abundance of carbon monoxide (CO) since March 2000. Direct emissions of CO are mainly produced by incomplete combustion from both natural fires and anthropogenic activities, and CO is also produced chemically from methane and volatile organic carbon (VOC) species. CO plays an important role in atmospheric chemistry and climate because it is a dominant sink for the hydroxyl radical (OH) and thus affects the abundance of methane (CH4) and ozone (O3). Anthropogenic emissions of CO have a significant indirect radiative forcing of 0.22 W/m2. Satellite measurements of carbon monoxide are used to understand how pollution is emitted and transported globally, from large scale fires to urban sources. I will present an overview of the MOPITT mission and show recent science results using MOPITT CO data, including highlights on how MOPITT data are assimilated for understanding model chemistry and emissions. I will also discuss the future of satellite CO observations.


Title:

Speaker: Cathy Martin and Bryan Begun
Date/Time: Thursday, October 10, 2019 03:00 PM
Location: David Skaggs Research Center, GC402 (multi-purpose room)
Abstract


Title:

The 20 gigaton carbon removal industry: Innovation and engineering for economy-wide negative emissions system.

Speaker: David Babson
Date/Time: Thursday, October 17, 2019 03:00 PM
Location: David Skaggs Research Center, GC402 (multi-purpose room)
Abstract


Title:

Resolving the Dust Bowl Paradox of Grassland Responses to Extreme Drought

Speaker: Alan Knapp, Colorado State University
Date/Time: Tuesday, November 5, 2019 03:00 PM
Location: David Skaggs Research Center, GC402 (multi-purpose room)
Abstract
During the 1930’s Dust Bowl drought, a decade of low rainfall and high temperatures in the central United States, widespread increases of species with the C3 photosynthetic pathway were observed in grasslands formerly dominated by C4 grasses. An increase in C3 species during hot, dry conditions is inconsistent with the predominant global distribution of C3 grasslands at cooler, high latitudes, as well as the generally lower thermal optima for photosynthesis and less efficient water use for C3 vs. C4 pathways. Understanding the mechanism for this response is important because vegetation canopies dominated by plants with C3 vs. C4 photosynthesis differ fundamentally in both pattern and magnitude of biosphere- atmosphere exchanges of carbon, water, and energy. We experimentally imposed four years of extreme drought in native C4 and C3-dominated grasslands in Kansas and Wyoming and, consistent with Dust Bowl observations, documented 3-5-fold increases in C3 relative to C4 grass biomass. To resolve this paradox, we show that under normal climate conditions in the central US, C4 grass biomass is greatest where precipitation inputs and temperature are strongly and positively related (warmer months are wetter months). In contrast, C3 grasses flourish where precipitation is less coupled to warm temperatures. We then analyzed historic climate records and find that the positive temperature-precipitation relationships that favor C4 grasses are consistently weakened by extreme drought. Thus, although extreme drought reduces precipitation overall, the proportion of precipitation in cooler months increases, enabling C3 grasses to increase. The frequency and duration of extreme drought in North America and globally is expected to increase with climate warming. To date, most attention has been focused on the severity of climate extremes, but our findings highlight how extreme drought can also alter precipitation seasonality, shift ecosystem phenology and lead to carbon cycle consequences that differ dramatically from those expected from the traits of C3 and C4 species.

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