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Extreme Outliers in Lower Stratospheric Water Vapor Over North America Observed by MLS: Relation to Overshooting Convection Diagnosed From Colocated Aqua‐MODIS Data
Author(s) -
Werner F.,
Schwartz M. J.,
Livesey N. J.,
Read W. G.,
Santee M. L.
Publication year - 2020
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2020gl090131
Subject(s) - microwave limb sounder , stratosphere , water vapor , environmental science , moderate resolution imaging spectroradiometer , atmospheric sciences , climatology , geology , meteorology , physics , satellite , astronomy
Convectively injected water vapor (H 2 O) in the North American (NA) summer lowermost stratosphere results in significant outliers in the 100‐hPa H 2 O measurements from the Aura Microwave Limb Sounder (MLS). MLS statistics from 15 years confirm that the NA region contains over 60% of global 100‐hPa H 2 O > 12 ppmv, despite having only ∼ 1.8% of all MLS observations. A profile sampled in August 2019 stands out, withH 2 O = 26 . 3 ppmv, far exceeding the prior record and the median ∼ 4.5‐ppmv abundance in NA. This particular outlier is associated with a large overshooting convective event (OCE) that spanned multiple U.S. states and persisted for several hours. Colocation of the MLS data over NA with cloud observations from Aqua's Moderate Resolution Imaging Spectroradiometer (MODIS) reveals the unique character of this case, as only 2.3% of MLS profiles are as close to an OCE and only 0.024% of OCEs cover as large an area within a 500‐km perimeter of a profile.