Earth's Mesosphere During Possible Encounters With Massive Interstellar Clouds 2 and 7 Million Years Ago

Autor: Jesse A. Miller, Merav Opher, Maria Hatzaki, Kyriakoula Papachristopoulou, Brian C. Thomas
Jazyk: angličtina
Rok vydání: 2024
Předmět:
Zdroj: Geophysical Research Letters, Vol 51, Iss 17, Pp n/a-n/a (2024)
Druh dokumentu: article
ISSN: 1944-8007
0094-8276
DOI: 10.1029/2024GL110174
Popis: Abstract Our solar system's path has recently been shown to potentially intersect dense interstellar clouds 2 and 7 million years ago: the Local Lynx of Cold Cloud and the edge of the Local Bubble. These clouds compressed the heliosphere, directly exposing Earth to the interstellar medium. Previous studies that examined climate effects of these encounters argued for an induced ice age due to the formation of global noctilucent clouds (NLCs). Here, we revisit such studies with a modern 2D atmospheric chemistry model using parameters of global heliospheric magnetohydrodynamic models as input. We show that NLCs remain confined to polar latitudes and short seasonal lifetimes during these dense cloud crossings lasting ∼105 years. Polar mesospheric ozone becomes significantly depleted, but the total ozone column broadly increases. Furthermore, we show that the densest NLCs lessen the amount of sunlight reaching the surface instantaneously by up to 7% while halving outgoing longwave radiation.
Databáze: Directory of Open Access Journals
Externí odkaz: