Identification

Title

Stratospheric transit time distributions derived from satellite water vapor measurements

Abstract

Stratospheric transit time distributions (age‐of‐air spectra) are estimated using time series of satellite water vapor (H 2 O) measurements from the Microwave Limb Sounder over 2004 to 2021 assuming stationary transport. Latitude‐altitude dependent spectra are derived from correlations of interannual H 2 O anomalies with respect to the tropical tropopause source region, fitted with an inverse Gaussian distribution function. The reconstructions accurately capture interannual H 2 O variability in the “tropical pipe” and near‐global lower stratosphere, regions of relatively fast transport (∼1–2 years) in the Brewer‐Dobson circulation. The calculations provide novel observational estimates of the corresponding “short transit‐time” part of the age spectrum in these regions, including the mode. However, the H 2 O results do not constrain the longer transit‐time “tail” of the age spectra, and the mean age of air and spectral widths are systematically underestimated compared to other data. We compare observational results with parallel calculations applied to the WACCM chemistry‐climate model and the CLaMS chemistry‐transport model, and additionally evaluate the method in CLaMS by comparing with spectra from idealized pulse tracers. Because the age spectra accurately capture H 2 O interannual variations originating from the tropical tropopause, they can be used to identify “other” sources of variability in the lower stratosphere, and we use these calculations to quantify H 2 O anomalies in the Southern Hemisphere linked to the Australian New Years fires in early 2020 and the Hunga volcanic eruption in 2022.

Resource type

document

Resource locator

Unique resource identifier

code

https://n2t.net/ark:/85065/d78p64t6

codeSpace

Dataset language

eng

Spatial reference system

code identifying the spatial reference system

Classification of spatial data and services

Topic category

geoscientificInformation

Keywords

Keyword set

keyword value

Text

originating controlled vocabulary

title

Resource Type

reference date

date type

publication

effective date

2016-01-01T00:00:00Z

Geographic location

West bounding longitude

East bounding longitude

North bounding latitude

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Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2024-11-01T00:00:00Z

Frequency of update

Quality and validity

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Conformity

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version of format

Constraints related to access and use

Constraint set

Use constraints

Limitations on public access

None

Responsible organisations

Responsible party

contact position

OpenSky Support

organisation name

UCAR/NCAR - Library

full postal address

PO Box 3000

Boulder

80307-3000

email address

opensky@ucar.edu

web address

http://opensky.ucar.edu/

name: homepage

responsible party role

pointOfContact

Metadata on metadata

Metadata point of contact