English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Fugitive emissions from waste disposal sites are importantanthropogenic sources of the greenhouse gas methane (CH4). Asa result of the growing world population and the recognition of the need tocontrol greenhouse gas emissions, this anthropogenic source of CH4has received much recent attention. However, the accurate assessment of theCH4 emissions from landfills by modeling and existing measurementtechniques is challenging. This is because of inaccurate knowledge of themodel parameters and the extent of and limited accessibility to landfillsites. This results in a large uncertainty in our knowledge of the emissionsof CH4 from landfills and waste management. In this study, we present results derived from data collected during theresearch campaign COMEX (CO2 and MEthane eXperiment) in late summer2014 in the Los Angeles (LA) Basin. One objective of COMEX, which comprisedaircraft observations of methane by the remote sensing Methane AirborneMAPper (MAMAP) instrument and a Picarro greenhouse gas in situ analyzer, wasthe quantitative investigation of CH4 emissions. Enhanced CH4 concentrations or <q>CH4 plumes</q> were detecteddownwind of landfills by remote sensing aircraft surveys. Subsequent to eachremote sensing survey, the detected plume was sampled within the atmosphericboundary layer by in situ measurements of atmospheric parameters such as windinformation and dry gas mixing ratios of CH4 and carbon dioxide(CO2) from the same aircraft. This was undertaken to facilitate theindependent estimation of the surface fluxes for the validation of the remotesensing estimates. During the COMEX campaign, four landfills in the LA Basin were surveyed. Onelandfill repeatedly showed a clear emission plume. This landfill, the OlindaAlpha Landfill, was investigated on 4 days during the last week of Augustand first days of September 2014. Emissions were estimated for all days usinga mass balance approach. The derived emissions vary between 11.6 and17.8 kt CH4 yr−1 with related uncertainties in the range of 14to 45 %. The comparison of the remote sensing and in situ basedCH4 emission rate estimates reveals good agreement within the errorbars with an average of the absolute differences of around2.4 kt CH4 yr−1 (±2. 8 kt CH4 yr−1). The USEnvironmental Protection Agency (EPA) reported inventory value is11.5 kt CH4 yr−1 for 2014, on average2.8 kt CH4 yr−1 (±1. 6 kt CH4 yr−1) lower thanour estimates acquired in the afternoon in late summer 2014. This differencemay in part be explained by a possible leak located on the southwesternslope of the landfill, which we identified in the observations of theAirborne Visible/Infrared Imaging Spectrometer – Next Generation (AVIRIS-NG)instrument, flown contemporaneously aboard a second aircraft on 1 day

Methane emissions from a Californian landfill, determined from airborne remote sensing and in situ measurements