A new Himalayan ice core CH 4 record: possible hints at the preindustrial latitudinal gradient

• Published in: Climate of the Past
• Main Authors: S. Hou, J. Chappellaz, D. Raynaud, V. Masson-Delmotte, J. Jouzel, P. Bousquet, D. Hauglustaine
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2013
• Subjects: Environmental pollution; TD172-193.5; Environmental protection; TD169-171.8; Environmental sciences; GE1-350; Antarctic; Greenland; Antarc*; glacier; ice core
• Online Access: https://doi.org/10.5194/cp-9-2549-2013; https://doaj.org/article/e7cebedc3f9a4014839460d217ac4f3f

Two ice cores recovered from the Himalayan East Rongbuk (ER) Glacier on the northeast saddle of Mt. Qomolangma (Everest) (28°01' N, 86°58' E, 6518 m above sea level) give access to a tentative record of past Himalayan atmospheric mixing ratio of CH 4 spanning the past 1200 yr. The major part of the record is affected by artifacts probably due to in situ production. After selecting what may represent the true atmospheric mixing ratio, an average of 749 ± 25 ppbv of CH 4 is estimated for the late preindustrial Holocene, which is ~ 36 ± 17 (~ 73 ± 18) ppbv higher than the atmospheric levels recorded in the Greenland (Antarctic) ice cores. A comparison of these new data with model simulations of the CH 4 latitudinal gradient suggests either that the models do not get a correct balance between high and low latitude CH 4 sources, or that the filtered CH 4 profile from the ER cores remains biased by small artifacts.