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 Plus annual

Presents the access of premium content as premium feature

Premium Content

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 annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Two quantitative retrieval techniques were evaluated to estimate methane(CH4) enhancement in concentrated plumes using high spatial andmoderate spectral resolution data from the Airborne Visible/Infrared ImagingSpectrometer (AVIRIS). An iterative maximum a posteriori differentialoptical absorption spectroscopy (IMAP-DOAS) algorithm performed well for anocean scene containing natural CH4 emissions from the Coal Oil Point(COP) seep field near Santa Barbara, California. IMAP-DOAS retrievalprecision errors are expected to equal between 0.31 to 0.61 ppm CH4over the lowest atmospheric layer (height up to 1.04 km), corresponding toabout a 30 to 60 ppm error for a 10 m thick plume. However, IMAP-DOASresults for a terrestrial scene were adversely influenced by the underlyingland cover. A hybrid approach using singular value decomposition (SVD) wasparticularly effective for terrestrial surfaces because it could betteraccount for spectral variability in surface reflectance. Using thisapproach, a CH4 plume was observed extending 0.1 km downwind of twohydrocarbon storage tanks at the Inglewood Oil Field in Los Angeles,California (USA) with a maximum near surface enhancement of 8.45 ppm abovebackground. At COP, the distinct plume had a maximum enhancement of 2.85 ppmCH4 above background, and extended more than 1 km downwind of knownseep locations. A sensitivity analysis also indicates CH4 sensitivityshould be more than doubled for the next generation AVIRIS sensor (AVIRISng)due to improved spectral resolution and sampling. AVIRIS-like sensors offerthe potential to better constrain emissions on local and regional scales,including sources of increasing concern like industrial point sourceemissions and fugitive CH4 from the oil and gas industry

Retrieval techniques for airborne imaging of methane concentrations using high spatial and moderate spectral resolution: application to AVIRIS