Enhanced response of global wetland methane emissions to the 2015–2016 El Niño-Southern Oscillation event
Year: 2018
Type: article
Abstract: Wetlands are thought to be the major contributor to interannual variability in the growth rate of atmospheric methane (CH 4 ) with anomalies driven by the influence of the El Niño-Southern Oscillation (ENSO). Yet it remains unclear whether (i) the increase in total global CH 4 emissions during El Niño versus La Niña events is from wetlands and (ii) how large the contribution of wetland CH 4 emissions is to the interannual variability of atmospheric CH 4 . We used a terrestrial ecosystem model that includes permafrost and wetland dynamics to estimate CH 4 emissions, forced by three separate meteorological reanalyses and one gridded observational climate dataset, to simulate the spatio-temporal dynamics of wetland CH 4 emissions from 1980–2016. The simulations show that while wetland CH 4 responds with negative annual anomalies during the El Niño events, the instantaneous growth rate of wetland CH 4 emissions exhibits complex phase dynamics. We find that wetland CH 4 instantaneous growth rates were declined at the onset of the 2015–2016 El Niño event but then increased to a record-high at later stages of the El Niño event (January through May 2016). We also find evidence for a step increase of CH 4 emissions by 7.8±1.6 Tg CH 4 yr −1 during 2007–2014 compared to the average of 2000–2006 from simulations using meteorological reanalyses, which is equivalent to a ~3.5 ppb yr −1 rise in CH 4 concentrations. The step increase is mainly caused by the expansion of wetland area in the tropics (30°S–30°N) due to an enhancement of tropical precipitation as indicated by the suite of the meteorological reanalyses. Our study highlights the role of wetlands, and the complex temporal phasing with ENSO, in driving the variability and trends of atmospheric CH 4 concentrations. In addition, the need to account for uncertainty in meteorological forcings is highlighted in addressing the interannual variability and decadal-scale trends of wetland CH 4 fluxes.
Source: Environmental Research Letters
Language: English
Subfield: Global and Planetary Change
Field: Environmental Science
Domain: Physical Sciences
SDG: Climate action
Open Access status: gold
Estimated APC paid: $3,045
Funders: National Aeronautics and Space Administration, Gordon and Betty Moore Foundation, University of East Anglia, National Natural Science Foundation of China, Competence Center Environment and Sustainability, European Centre for Medium-Range Weather Forecasts, National Oceanic and Atmospheric Administration
Awards: G1888610284, THE ABOVE FIELD CAMPAIGN WILL IMPROVE OUR UNDERSTANDING OF ONE OF THE MOST DYNAMIC REGIONS ON THE PLANET THE ARCTIC BOREAL REGION ABR WHERE CHANGES IN CLIMATE ARE PROGRESSING MOST RAPIDLY AND ARE ALREADY TRIGGERING CHANGES TO ECOSYSTEM CARBON STORAGE. WHILE THE IMPORTANCE OF THE ABR IN THE GLOBAL CARBON CYCLE IS WELL ESTABLISHED OUR FUNDAMENTAL UNDERSTANDING OF THE MAGNITUDE BEHAVIOR AND FATE OF CARBON POOLS IN THIS DOMAIN REMAINS INCOMPLETE. THE FIRST ABOVE AIRBORNE CAMPAIGN WILL PROVIDE CRITICAL OBSERVATIONS NEEDED TO UNDERSTAND PERMAFROST CARBON DYNAMICS. THESE UNIQUE DATASETS COMPLEMENT EXISTING MONITORING NETWORKS THAT ARE LIMITED IN SPATIAL COVERAGE GROUND OR SPATIAL RESOLUTION SATELLITE. STRATEGICALLY INTEGRATING THE INFORMATION COLLECTED DURING THE ABOVE CAMPAIGN INTO A HIGH RESOLUTION SCALABLE AND GLOBAL LAND ATMOSPHERE MODEL IS A VITAL STEP TOWARDS ACHIEVING THE SCIENCE OBJECTIVES OF THE MISSION. WE PROPOSE TO DELIVER A HIGHLY INTEGRATED MODELING FRAMEWORK USING NASAS GEOS 5 SYSTEM THAT WILL RELY ON MULTI SCALE DATA STREAMS FROM ABOVE TO INFORM AND IMPROVE PROCESS BASED REPRESENTATION OF PERMAFROST CARBON DYNAMICS. WE WILL ADOPT A THREE PRONGED APPROACH WHICH INCLUDES A ANALYZING AND INTERPRETING THE AIRBORNE PRIMARILY THE FOUNDATIONAL MEASUREMENTS THAT WILL BE COLLECTED DURING THE 2017 ABOVE AIRBORNE CAMPAIGN B INTEGRATING THE AIRBORNE INFORMATION INTO A DYNAMIC VEGETATION MODELING FRAMEWORK LPJ WSL TAILORED FOR THE ABOVE STUDY DOMAIN AND C USING THE COUPLED HIGH RESOLUTION GEOS 5 LPJ WSL FRAMEWORK TO IMPROVE OUR UNDERSTANDING OF THE PERMAFROST CARBON BOTH CO2 AND CH4 EMISSIONS AND ASSOCIATED FEEDBACKS AT A VARIETY OF SPATIOTEMPORAL SCALES. IN ORDER TO MAXIMIZE THE SCIENTIFIC RETURN OF THE EARLY MISSION DATA FROM THE 2017 CAMPAIGN WE WILL ALSO LEVERAGE DATA FROM EXISTING REMOTE SENSING MISSIONS SMAP LANDSAT 7 8 OCO 2 PREVIOUS AIRBORNE CAMPAIGNS CARVE AND GROUND BASED MEASUREMENTS AS APPLICABLE. DURING THE AIRBORNE CAMPAIGN WE WILL USE GEOS 5 TO PRODUCE HIGH RESOLUTION FORECASTS OF METEOROLOGY AEROSOLS AND TRACE GASES IN NEAR REAL TIME AND SUPPORT FLIGHT PLANNING. WE WILL ALSO PROVIDE STATISTICAL ANALYSES OF CLEAR SKY CONDITIONS AND TRACE GAS PLUMES TO THE ABOVE TEAM TO GUIDE PLANNING OF THE OPTICAL FOR AVIRIS NG LVIS SENSORS IN ADVANCE OF DEPLOYMENT. THE GEOS 5 MODEL HAS CONTRIBUTED TO NUMEROUS FIELD CAMPAIGNS AND THE INCLUSION OF TRACE GAS AND AEROSOL FIELDS CAN INFORM MISSION PLANNING BY REPRESENTING EMISSIONS PROCESSES BEING TARGETED OR FACTORS THAT CAN CONFOUND MEASUREMENTS. ONGOING AND RECENT DEVELOPMENTS WITHIN THE GEOS 5 LPJ WSL FRAMEWORK ARE UNIQUELY SUITED TO ADDRESS THE SCIENCE GOALS OF ABOVE. ITS ABILITY TO RUN AT SPATIAL RESOLUTIONS OF 12 5 50 KM IS COMPARABLE TO RESOLUTIONS USED BY REGIONAL MODELS BUT BECAUSE IT IS A GLOBAL MODEL IT CAN READILY EXTEND LESSONS LEARNED TO THE PAN ARCTIC SCALE TO REALISTICALLY SIMULATE CARBON CLIMATE INTERACTIONS IN THE PRESENT AND FUTURE. BY PERFORMING RIGOROUS COMPARISONS BETWEEN AIRBORNE AND SATELLITE OBSERVATIONS THIS EFFORT WILL ALSO HELP INFORM OBSERVING STRATEGIES AND MAXIMIZE THE USE OF SATELLITE DATA IN THIS COMPLEX REGION. THE PROPOSED STUDY THUS ADDRESSES BOTH THE CONCEPTUAL BASIS FOR ABOVE AS WELL AS NASA EARTH SCIENCES STRATEGIC GOAL TO QUANTIFY AND DOCUMENT CHANGES TO THE CARBON CYCLE IN THE HIGH LATITUDES., Advancing Understanding of the Global Methane Cycle, THIS DOCUMENT OUTLINES WORK TO BE DONE AT USRA GESTAR/NASA GSFC FOR A PROPOSAL TO NASA AS PART OF A COLLABORATIVE RESEARCH PROJECT BETWEEN NASA JPL,
OpenAlex ID: W2805537128