ISSI Venus Proposal 9-11-2007

8/12/2019 ISSI Venus Proposal 9-11-2007

1/11

ISSI Proposal: 8-9 Nov. 2007

Proposal for an ISSI projet

Understanding the atmosphere of Venus

Scientific background

Lennart Bengtssonwith Roger Bonnet and Andr Balogh


2/11


S!ent!f! rat!onale" #e nee$ to %etter un$erstan$ the atmosphere of Venus to

$emonstrate the &eneral!t!es of mo$els of planetar'atmospheres presentl' ma!nl' teste$ for the (arth. Ne)o%servat!ons from (SA Venus (*press an$ soon from thePlanet-+ %' ,apan !s sett!n& a su!ta%le t!me she$ule.

" Venus !s here a pr!mar' an$!$ate as there are %oth s!m!lar!t!esan$ ons!$era%le $!fferenes to the (arth

" #e ma' %e a%le to o%ta!n further !ns!&ht !n the evolut!on of the

Venus atmosphere. as there %een a &reenhouse run-a)a'effet on Venus

" #e ma' o%ta!n further !ns!&ht !nto the lon&-term future of the(arth !f %e!n& e*pose$ to mass!ve &reenhouse &ases !n thefuture.


3/11


What do the dynamical regimes of Venus and Earth have in common?What do the dynamical regimes of Venus and Earth have in common?

What accounts for the differences in the atmospheric dynamics ofWhat accounts for the differences in the atmospheric dynamics of

these planets?these planets?

Why study Venus atmospheric dynamics to understand the dynamicsWhy study Venus atmospheric dynamics to understand the dynamics

of Earths atmosphere?of Earths atmosphere?


4/11


Major Dynamical Features of Earths AtmosphereMajor Dynamical Features of Earths Atmosphere

Tropical Hadley cell confined to equatorial latitudes (30).

QBO

Ferrel cells and polar cells.

Subtropical jet stream.Large-scale baroclinic eddies in mid-latitudes.

Thermal tides.

Planetary waves.

Mesopause over the equator is colder than over the winter pole.

Seasonal variations.

Major Dynamical Features of Venus AtmosphereMajor Dynamical Features of Venus Atmosphere

Superrotation.

Polar vortex.

High latitude cloud level jet stream.

Cloud level Hadley cell extending to polar latitudes?

Thermal tides?

Planetary waves.

Mesospheric (70-100 km) temperature increase from equator to the pole.Seasonal variations?


5/11


Earth and VenusEarth and Venus

There may be more similarity between Earth and Venus than

hitherto appreciated.Earths circulation is driven from below by solar heating variations.

On Venus, solar heating is focused at cloud heights where T, p

conditions are earthlike. The cloud level circulation on Venus might

have some similar characteristics as circulation on Earth. Recent

Venus GCM calculations by Sebastien Lebonnois suggest that

atmospheric circulation is driven largely from above, at cloud levels,

where solar heating is concentrated, with the lower massive

atmosphere playing a more passive role. Earthlike features include a

cloud level Hadley cell and high latitude jets.


6/11


Lebonnois (2007)


7/11ISSI Proposal: 8-9 Nov. 2007

Earth and Venus

The polar vortex on Venus may have some dynamical similarities

to Earths hurricanes and stratospheric polar vortex.

P!oneer Venus

/I !ma&e19803

super!mpose$

on 4ar!ner 0

5V !ma&es

19763

Figure courtesy

of Sanjay

Limaye

Venus (*press

VITIS 5V an$NI !ma&es

12003

Downloaded

from VEX !e"

site


8/11ISSI Proposal: 8-9 Nov. 2007

elevane for the (arths l!mate

!n the lon&er perspet!ve" Is !t a r!s that there )!ll %e a run-a)a' l!mate on the

(arth

" Pro%a%l' not as there are ounterat!n& proesses !n

the (arth;s atmosphere suh as lou$s at!n& as a

sort of thermostat an$ that heat !s transporte$ to

h!&her lat!tu$es )here ool!n& !s more eff!!ent.

"


9/11


Projet /utl!ne

Three sta&e proposal Stage 1

Invite an expert group on the atmospheres of Venusand Earthto a meeting in ISSI with the purpose of

defining/refining the scientific objectives of the

elements of the project and to make concrete

proposals for its scope and implementation. (Firstquarter 2008)


10/11


Projet /utl!ne


Set up an ISSI Working Groupon the scientific and technicalaspects of modelling the atmospheres of Venus and Earth.

This WG would review the status of Venus atmosphericmodels and the applicability of terrestrial models to Venus. Itwould also review the research currently carried out intomodelling the Venus atmosphere and define/propose newmethodologies. The output of the WG would be (a) a book inthe ISSI Scientific Report Series and (b) technical and

methodological input to the preparation of the Workshopoutlined below. (The WG, of about 10 or so members, with adhoc experts as appropriate would start their work in the firsthalf of 2008, with a target duration of 1 year.)


11/11


Projet /utl!ne


Initiate an ISSI Workshop on the atmosphere of Venus, to be

held in 2009.The main objective of such a workshop shouldbe to summarize the knowledge situation and to explore howmodelling and observational data could be suitably integrated.The expert group would advise on the detailed scope andcontents of the Workshop and recommend a group of aboutfive scientists to act as Convenors for the Workshop. It isproposed that the first meeting of the Convenors would takeplace in the 3rdquarter of 2008.

ISSI Venus Proposal 9-11-2007

Documents

Transcript of ISSI Venus Proposal 9-11-2007