Overestimated acceleration of the advective Brewer-Dobson circulation due to stratospheric cooling

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00216208%3A11320%2F20%3A10421918" target="_blank" >RIV/00216208:11320/20:10421918 - isvavai.cz</a>

Result on the web

<a href="https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=7oy4D9qH9n" target="_blank" >https://verso.is.cuni.cz/pub/verso.fpl?fname=obd_publikace_handle&handle=7oy4D9qH9n</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.1002/qj.3876" target="_blank" >10.1002/qj.3876</a>

Result language

angličtina

Original language name

Overestimated acceleration of the advective Brewer-Dobson circulation due to stratospheric cooling

Original language description

Tropospheric warming and stratospheric cooling influence the vertical structure of the atmosphere. Numerous studies have analysed the thermal expansion of the troposphere, however, stratospheric cooling reverses the sign of this shift in the middle stratosphere, causing a downward shift in the upper stratosphere and mesosphere. This is a robust feature in transient climate model simulations, but its impact is commonly unappreciated. Here, we quantify the trend difference of the residual mean vertical velocity (w?*), a proxy for diagnosing the advective Brewer-Dobson circulation (BDC) strength, which arises from implicit neglect of the shrinking distance between stratospheric pressure levels in the CCMI-1 (Chemistry-Climate Model Initiative part 1) data request. There, a log-pressure formula with constant scale height is recommended to computew?*. However, stratospheric cooling in transient climate simulations causes a reduction of the geometrical distance between pressure levels and thereby also the scale height significantly decreases over time. Using the general scale height definition for the transformation, thew?*trends are therefore smaller. In both cases, the units are m center dot s(-1), but in the latter case it is the constant measure of length geopotential metres and not log-pressure metres. We quantify that, due to the temperature dependence of log-pressure metres, past studies that basedw?*trend analyses on log-pressurew?*overestimated the advective BDC acceleration by similar to 20%. This result is consistent among the CCMI-1 projections over the 1960-2100 period. We highlight that other diagnostics can also be affected by the neglect of the declining stratospheric pressure level distance. A detailed description of the diagnostics is necessary for consistent assessments of trends. Data processing tools should generally not include the constant scale height assumption if the data are used for trend analyses.

Czech name

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Czech description

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Type

J_imp - Article in a specialist periodical, which is included in the Web of Science database

CEP classification

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OECD FORD branch

10509 - Meteorology and atmospheric sciences

Project

<a href="/en/project/EF19_074%2F0016231" target="_blank" >EF19_074/0016231: International mobility of researchers at Charles University (MSCA-IF III)</a><br>

Continuities

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)<br>I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2020

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Quarterly Journal of the Royal Meteorological Society

ISSN

0035-9009

e-ISSN

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Volume of the periodical

146

Issue of the periodical within the volume

733

Country of publishing house

GB - UNITED KINGDOM

Number of pages

15

Pages from-to

3850-3864

UT code for WoS article

000566554900001

EID of the result in the Scopus database

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