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Enhanced methane emissions from tropical wetlands during the 2011 La Ni ñ a

View Article: PubMed Central - PubMed

ABSTRACT

Year-to-year variations in the atmospheric methane (CH4) growth rate show significant correlation with climatic drivers. The second half of 2010 and the first half of 2011 experienced the strongest La Niña since the early 1980s, when global surface networks started monitoring atmospheric CH4 mole fractions. We use these surface measurements, retrievals of column-averaged CH4 mole fractions from GOSAT, new wetland inundation estimates, and atmospheric δ13C-CH4 measurements to estimate the impact of this strong La Niña on the global atmospheric CH4 budget. By performing atmospheric inversions, we find evidence of an increase in tropical CH4 emissions of ∼6–9 TgCH4 yr−1 during this event. Stable isotope data suggest that biogenic sources are the cause of this emission increase. We find a simultaneous expansion of wetland area, driven by the excess precipitation over the Tropical continents during the La Niña. Two process-based wetland models predict increases in wetland area consistent with observationally-constrained values, but substantially smaller per-area CH4 emissions, highlighting the need for improvements in such models. Overall, tropical wetland emissions during the strong La Niña were at least by 5% larger than the long-term mean.

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Related in: MedlinePlus

(a,b) Detrended and smoothened regionally averaged precipitation and temperature measurements over land in CRU-TS version 3.23 (Climatic Research Unit-time series33). (c) Anomalies in the total inundated area estimated by SWAMPS37.
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f3: (a,b) Detrended and smoothened regionally averaged precipitation and temperature measurements over land in CRU-TS version 3.23 (Climatic Research Unit-time series33). (c) Anomalies in the total inundated area estimated by SWAMPS37.

Mentions: Figure 3a and b show monthly anomalies recorded in climate parameters. A significant redistribution of heat and precipitation is seen during the different phases of ENSO. was −1.72, 4.90, and 0.64 mm during EN10, LN11, and LN12, respectively. During LN11 the precipitation anomaly in TRO (and in GLO) was the highest since the onset of the 21st century (see SM Figure 10). Regions like Australia had six consecutive seasons of increased rainfall over the La Niña of 2011 and 201248. Higher temperatures were observed in NET during LN11 ( = 0.18 °C), favoring increased biomass burning, for example, near Moscow during the summer of 20104950. Mean temperatures during LN11 ( = −0.05 °C) were in between those during EN10 ( = 0.15 °C) and LN12 ( = −0.22 °C).


Enhanced methane emissions from tropical wetlands during the 2011 La Ni ñ a
(a,b) Detrended and smoothened regionally averaged precipitation and temperature measurements over land in CRU-TS version 3.23 (Climatic Research Unit-time series33). (c) Anomalies in the total inundated area estimated by SWAMPS37.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC5385533&req=5

f3: (a,b) Detrended and smoothened regionally averaged precipitation and temperature measurements over land in CRU-TS version 3.23 (Climatic Research Unit-time series33). (c) Anomalies in the total inundated area estimated by SWAMPS37.
Mentions: Figure 3a and b show monthly anomalies recorded in climate parameters. A significant redistribution of heat and precipitation is seen during the different phases of ENSO. was −1.72, 4.90, and 0.64 mm during EN10, LN11, and LN12, respectively. During LN11 the precipitation anomaly in TRO (and in GLO) was the highest since the onset of the 21st century (see SM Figure 10). Regions like Australia had six consecutive seasons of increased rainfall over the La Niña of 2011 and 201248. Higher temperatures were observed in NET during LN11 ( = 0.18 °C), favoring increased biomass burning, for example, near Moscow during the summer of 20104950. Mean temperatures during LN11 ( = −0.05 °C) were in between those during EN10 ( = 0.15 °C) and LN12 ( = −0.22 °C).

View Article: PubMed Central - PubMed

ABSTRACT

Year-to-year variations in the atmospheric methane (CH4) growth rate show significant correlation with climatic drivers. The second half of 2010 and the first half of 2011 experienced the strongest La Niña since the early 1980s, when global surface networks started monitoring atmospheric CH4 mole fractions. We use these surface measurements, retrievals of column-averaged CH4 mole fractions from GOSAT, new wetland inundation estimates, and atmospheric δ13C-CH4 measurements to estimate the impact of this strong La Niña on the global atmospheric CH4 budget. By performing atmospheric inversions, we find evidence of an increase in tropical CH4 emissions of ∼6–9 TgCH4 yr−1 during this event. Stable isotope data suggest that biogenic sources are the cause of this emission increase. We find a simultaneous expansion of wetland area, driven by the excess precipitation over the Tropical continents during the La Niña. Two process-based wetland models predict increases in wetland area consistent with observationally-constrained values, but substantially smaller per-area CH4 emissions, highlighting the need for improvements in such models. Overall, tropical wetland emissions during the strong La Niña were at least by 5% larger than the long-term mean.

No MeSH data available.


Related in: MedlinePlus