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

Kód výsledku v 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>

Výsledek na webu

<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>

Jazyk výsledku

angličtina

Název v původním jazyce

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

Popis výsledku v původním jazyce

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.

Název v anglickém jazyce

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

Popis výsledku anglicky

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.

Druh

J_imp - Článek v periodiku v databázi Web of Science

CEP obor

—

OECD FORD obor

10509 - Meteorology and atmospheric sciences

Projekt

<a href="/cs/project/EF19_074%2F0016231" target="_blank" >EF19_074/0016231: Mobilita pracovníků UK MSCA-IF III</a><br>

Návaznosti

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

Rok uplatnění

2020

Kód důvěrnosti údajů

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

Název periodika

Quarterly Journal of the Royal Meteorological Society

ISSN

0035-9009

e-ISSN

—

Svazek periodika

146

Číslo periodika v rámci svazku

733

Stát vydavatele periodika

GB - Spojené království Velké Británie a Severního Irska

Počet stran výsledku

15

Strana od-do

3850-3864

Kód UT WoS článku

000566554900001

EID výsledku v databázi Scopus

—