Identification

Title

A mass-weighted isentropic coordinate for mapping chemical tracers and computing atmospheric inventories

Abstract

We introduce a transformed isentropic coordinate M theta(e), defined as the dry air mass under a given equivalent potential temperature surface (theta(e)) within a hemisphere. Like theta(e), the coordinate M-theta e follows the synoptic distortions of the atmosphere but, unlike theta(e), has a nearly fixed relationship with latitude and altitude over the seasonal cycle. Calculation of M-theta e is straightforward from meteorological fields. Using observations from the recent HIAPER Pole-to-Pole Observations (HIPPO) and Atmospheric Tomography Mission (ATom) airborne campaigns, we map the CO2 seasonal cycle as a function of pressure and M-theta e, where M-theta e is thereby effectively used as an alternative to latitude. We show that the CO2 seasonal cycles are more constant as a function of pressure using Moe as the horizontal coordinate compared to latitude. Furthermore, short-term variability in CO2 relative to the mean seasonal cycle is also smaller when the data are organized by M-theta e and pressure than when organized by latitude and pressure. We also present a method using M-theta e to compute mass-weighted averages of CO2 on a hemispheric scale. Using this method with the same airborne data and applying corrections for limited coverage, we resolve the average CO2 seasonal cycle in the Northern Hemisphere (mass-weighted tropospheric climatological average for 2009-2018), yielding an amplitude of 7.8 +/- 0.14 ppm and a downward zerocrossing on Julian day 173 +/- 6.1 (i.e., late June). M-theta e may be similarly useful for mapping the distribution and computing inventories of any long-lived chemical tracer.

Resource type

document

Resource locator

Unique resource identifier

code

http://n2t.net/ark:/85065/d75d8w7r

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

South bounding latitude

Temporal reference

Temporal extent

Begin position

End position

Dataset reference date

date type

publication

effective date

2021-01-12T00:00:00Z

Frequency of update

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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