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Atmospheric methane
About: Atmospheric methane is a research topic. Over the lifetime, 2034 publications have been published within this topic receiving 119616 citations.
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TL;DR: Kindler et al. as discussed by the authors showed that during the last glacial cycle, Greenland temperature showed many rapid temperature variations, the so-called Dansgaard-Oeschger (DO) events.
Abstract: . During the last glacial cycle, Greenland temperature showed many rapid temperature variations, the so-called Dansgaard–Oeschger (DO) events. The past atmospheric methane concentration closely followed these temperature variations, which implies that the warmings recorded in Greenland were probably hemispheric in extent. Here we substantially extend and complete the North Greenland Ice Core Project (NGRIP) methane record from the Preboreal Holocene (PB) back to the end of the last interglacial period with a mean time resolution of 54 yr. We relate the amplitudes of the methane increases associated with DO events to the amplitudes of the local Greenland NGRIP temperature increases derived from stable nitrogen isotope (δ15N) measurements, which have been performed along the same ice core (Kindler et al., 2014). We find the ratio to oscillate between 5 parts per billion (ppb) per °C and 18 ppb °C−1 with the approximate frequency of the precessional cycle. A remarkably high ratio of 25.5 ppb °C−1 is reached during the transition from the Younger Dryas (YD) to the PB. Analysis of the timing of the fast methane and temperature increases reveals significant lags of the methane increases relative to NGRIP temperature for DO events 5, 9, 10, 11, 13, 15, 19, and 20. These events generally have small methane increase rates and we hypothesize that the lag is caused by pronounced northward displacement of the source regions from stadial to interstadial. We further show that the relative interpolar concentration difference (rIPD) of methane is about 4.5% for the stadials between DO events 18 and 20, which is in the same order as in the stadials before and after DO event 2 around the Last Glacial Maximum. The rIPD of methane remains relatively stable throughout the full last glacial, with a tendency for elevated values during interstadial compared to stadial periods.
70 citations
TL;DR: In this article, a modified version of Fick's first law based on theoretical computations for diffusivity in aggregated media, together with a soil water balance model run on a 1δ global grid, was used to make independent estimates of CH4 uptake by soils worldwide.
70 citations
TL;DR: In this paper, the effects of morpho-physiological characteristics of rice (Oryza sativa L.) plants on methane emission from paddy fields were investigated. And the results showed that higher vegetative growth with high methane transport capacity may positively contribute to higher methane emission.
70 citations
TL;DR: In this paper, the eddy flux of methane (CH4) was measured over 14 months above a restored wetland in western Denmark, and the average annual daily CH4 flux was 30.2 mg m−2 d−1, but the daily emission rates varied considerably over time.
70 citations
TL;DR: In this article, a Picarro G2301 CRDS (Cavity Ring-Down Spectroscopy) analyser was installed on a vehicle, together with an anemometer and GPS receiver, to measure atmospheric methane mole fractions and their relative location while driving at speeds up to 80 kph.
69 citations