GC11B-1030
Compact Solar Spectrometer Column CO2, and CH4 Observations: Performance Evaluation at Multiple North American TCCON Sites
Monday, 14 December 2015
Poster Hall (Moscone South)
Harrison Alexander Parker1, Jacob Hedelius2, Camille Viatte2, Debra Wunch2, Paul O Wennberg3, Jia Chen4, Stephen Wofsy4, Taylor Jones4, Jonathan Franklin5 and Manvendra Krishna Dubey1, (1)Los Alamos National Laboratory, Los Alamos, NM, United States, (2)California Institute of Technology, Pasadena, CA, United States, (3)California Institute of Technology, Division of Engineering and Applied Science, Pasadena, CA, United States, (4)Harvard University, Cambridge, MA, United States, (5)Dalhousie University, Halifax, Canada
Abstract:
Measurement, reporting and verification (MRV) of anthropogenic emissions and natural sources and sinks of carbon dioxide (CO2) and methane (CH4) are crucial to predict climate change and develop transparent accounting policies to contain climate forcing. Remote sensing technologies are monitoring column averaged dry air mole fractions of CO2 and CH4 (XCO2 & XCH4) from ground and space (OCO-2 and GOSAT) with solar spectroscopy enabling direct MRV. However, current ground based coverage is sparse due to the need for large and expensive high-resolution spectrometers that are part of the Total Column Carbon Observing Network (TCCON, Bruker 125HR). This limits our MRV and satellite validation abilities, both regionally and globally. There are striking monitoring gaps in Asia, South America and Africa where the CO2 emissions are growing and there is a large uncertainty in fluxes from land use change, biomass burning and rainforest vulnerability. To fill this gap we evaluate the precision, accuracy and stability of compact, affordable and easy to use low-resolution spectrometers (Bruker EM27/SUN) by comparing with XCO2 and XCH4 retrieved from much larger high-resolution TCCON instruments. As these instruments will be used in a variety of locations, we evaluate their performance by comparing with 2 previous and 4 current United States TCCON sites in different regions up to 2700 km apart. These sites range from polluted to unpolluted, latitudes of 32 to 46°N, and altitudes of 230 to 2241 masl. Comparisons with some of these sites cover multiple years allowing assessment of the EM27/SUN performance not only in various regions, but also over an extended period of time and with different seasonal influences. Results show that our 2 EM27/SUN instruments capture the diurnal variability of the aforementioned constituents very well, but with offsets from TCCON and long-term variability which may be due in part to the extensive movement these spectrometers were subjected to. These off-the-shelf spectrometers should dramatically expand the coverage of regional XCO2 and XCH4 observations, particularly in gap regions. Increased temporal and spacial resolution on global carbon data will lead to more reliable information when considering climate change policy and funding.
