Air-sea/land interaction: physics and observation of planetary boundary layers and quality of environment

Mega-Grant, started November 1st 2011

University of Nizhny Novgorod, Russia

INSTITUTIONS-COLLABORATORS Institute of Applied Physics RAS; Faculty of Geography of Moscow State University; Russian State Hydrometeorological University; A.M. Obukhov Institute of Atmospheric Physics RAS – RUSSIA // Danish Meteorological

Institute – DENMARK // Finnish Meteorological Institute; Dept of Physics of University of Helsinki – Finland // Ben-Gurion University of the Negev –

ISRAEL // Nansen Environmental and Remote Sensing Centre – NORWAY…

WELCOME TO ADJOIN OUR PARTNERSHIP!

Mega-grants for environmental challenges 24-26.05.2012

Motivation Motivation and contentand content

Geophysical turbulence and planetary boundary layers (PBLs)

Physics Geo-sciences

New concepts of random and self-organised motions in geophysical turbulence

PBLs link atmosphere, hydrosphere, lithosphereand cryosphere within

weather & climate systems

Revision of basic theoryof turbulence and PBLs

Improved “linking algorithms”in weather & climate models

Progress in understanding and modelling

weather & climate systems

Geospheres in climate system

Atmosphere, hydrosphere, lithosphere and cryosphere are coupled through turbulent planetary boundary layers PBLs (dark green lenses)

PBLs include 90% biosphere and entire anthroposphere

http://www.jpgmag.com/photos/1006154

Role of planetary boundary layers (PBLs): TRADITIONAL VIEW

oceanocean

“Surface fluxes” throughAIRandWATER (or LAND) interfacesfully characterise interaction betweenATMOSPHERE-OCEAN / LAND

Monin-Obukhov similarity theory (1954) (conventional framework for determining surface fluxes in operational models) disregards non-local features of both convective and long-lived stable PBLs

http://www.jpgmag.com/photos/1006154

Role of PBLs: MODERN VIEWBecause of very stable stratification in the atmosphere and ocean beyond the PBLs and convective zones, strong density increments inherent in the PBL outer boundaries prevent entities delivered by surface fluxes or anthropogenic emissions to efficiently penetrate from the PBL into the free atmosphere or deep ocean.

Hence the PBL heights and the fluxes due to entrainment at the PBL outer boundaries essentially control extreme weather events (e.g., heat waves associated with convection; or strongly stable stratification events triggering air pollution).

This concept (equally relevant to the hydrosphere) brings forth the problem of determining the PBL depth and the turbulent entrainment in numerical weather prediction, air/water quality and climate modelling.

Very shallow boundary layer separated form the Very shallow boundary layer separated form the free atmosphere by capping inversionfree atmosphere by capping inversion

PBL height visualised by smoke blanket (Johan The Ghost, Wikipedia)

PBL height and air quality

http://www.jpgmag.com/photos/1006154

TasksGeophysical turbulence and PBLs Non-local nature Revision of

traditional theory Improved practical applications (SZ)

Atmospheric electricity Convective PBLs, thunderstorms, upper atmosphere role in global electric circuit applications (EM)

Air-sea interaction Processes at air-sea interface (theory, lab and field experiments) application to hurricanes, storms (YuT)

Internal waves Interaction with turbulence, wave-driven transports (ocean, ionosphere) role in climate machine (AK)

Chemical weather / climate Fires and modelling air pollution troposphere and middle atmosphere (AF)

New methods of radio-physical observations Instruments to respond new challenges turbulence, organised structures, chemical composition commercialisation (AF, AU)

Education and young-scientist programme new PhD, Dr.Sci.

http://www.jpgmag.com/photos/1006154

PBL and turbulence problemsSelf-organisation of turbulent convection

Failure of the MO similarity theory non-local resistance and heat/mass transfer laws (free and forced convection regimes); growth rate of and turbulent entrainment into convective PBLs

Non-local nature of stably stratified PBLs ”Long-lived stable” and “conventionally neutral” very shallow and therefore sensitive (typical of Polar areas and over ocean); diagnostic and prognostic PBL-height equations

Dead locks in and new concept of turbulence closure Potential energy, self-preservation of stably stratified turbulence no critical Richardson number; new “weak turbulence” regime with diminishing heat transfer (everywhere in the atmosphere and hydrosphere beyond PBLs and convective zones)

TURBULENT CONVECTIONTURBULENT CONVECTION

Photo J. GratzPhoto J. Gratz

LES I. Esau

Cloud streets visualising updraughts in convective rolls

In the atmosphere In LES

Development of convective cloudsSelf-organised cells in the atmosphere

Гора Леммон, Аризона

Cloud systems over North Polar Ocean

Convective cells

Weak wind

free convection

Convective rolls

Strong wind

forced convection

Self-organisation

Self-organisation in viscous convection is known since Benard (1900) and Rayleigh (1916)

It is obviously presents in turbulent convection but missed in essentially local classical theories:

Heat and mass transfer law Nu ~ Ra1/3

Prandtl theory of free convection Wc = (βFsz)1/3 Monin-Obukhov similarity theory L = τ 3/2 (βFs)-1

and in all parameterizations based on these theories

Revision of the theory is demanded

NON-LOCAL THEORY OF CONVECTIVE NON-LOCAL THEORY OF CONVECTIVE HEAT AND MASS TRANSFERHEAT AND MASS TRANSFER

Example of solved problem

Organised cell in turbulent convection (disregarded in classical theory)

Air-borne measurements, calm sunny day over Australian desert: arrows – winds; lines – temperatures (Williams and Hacker, 1992)

Heat and mass transfer in free convection:non-local theory

Self-organisation

Convective wind pattern includes the convergence flow towards the plume axes at the surface

Near-surface internal boundary layer

”minimum friction velocity U* (Businger,1973)

Strongly enhanced heat/mass transfer

Heat-transfer coefficient

Blue symbols observationsRed symbols LES Line theory

Classical theory (Nu = C0 Ra1/3)

disregards dependence on h/z0

and underestimates heat transfer over rough surfaces up to 2

orders of magnitude

Convective heat/mass transfer: conclusions

Classical (local) theory disregards self-organisation of turbulent convection and strongly underestimates heat/mass transfer in nature

Developed Non-local theory of free convection (cells, weak winds) Essential dependence of heat/mass transfer on the ratio of boundary-layer depth to roughness length (h/z0u)

New turbulent entrainment equation accounting for IGW mechanism

Under development Non-local theory of forced convection (rolls at strong winds)

Applications to modelling air flows over warm pool area in Tropical Ocean (free convection / known) openings in Polar ocean (forced convection / prospective) urban heat islands, deserts, etc. (prospective

Convection: principal statementConvective structures are supplied with energy through inverse energy cascade (from smaller to larger eddies). They resemble secondary circulations rather then large turbulent eddies

2h

Cloud streets visualising convective rolls stretched along the strong wind (Queensland, North Coast, Australia, Wikimedia

Commons; photo by Mick Petroff ) In both figures h ~ 103 м is the height of convective layer

Vertical cross-section of a convective cell at weak wind over Australian desert (airborne observations by Williams and Hacker, 1992)

TURBULENCE TURBULENCE IN STABLE STRATIFICATIONIN STABLE STRATIFICATION

Very shallow long-lived stable boundary layer over cold Lake Teletskoe (Altay, Russia) on 28 August 2010 (photo by S. Zilitinkevich). Smoke blanket visualises upper boundary

of the layer

NON-LOCAL THEORY OF LONG-NON-LOCAL THEORY OF LONG-LIVED STABLY-STRATIFIED LIVED STABLY-STRATIFIED

PLANETARY BOUNDARY LAYERSPLANETARY BOUNDARY LAYERS(PBLs)(PBLs)

Example of solved problem

S. Galmarini, JRC

Stable and neutral PBLsTraditional theory (adequate over land at mid latitudes)

• is valid in the presence of pronounced diurnal course of temperature•recogniseed only two types of stably or neutrally stratified PBL, REGARDLESS STATIC STABILITY AT PBL OUTER BOUNDARY:

stable (factually nocturnal stable – capped by residual layer)

neutral (factually truly neutral – capped by residual layer)

Non-local theory (2000-2010) • accounted for the free flow-PBL interaction through IGW or structures• led to discovery of additional types of PBL:

long-lived stable (50 % at high latitudes)

conventionally neutral (40 % over ocean)• both proved to be much shallower than mid-latitudinal PBLs

Temperature stratification in (a) nocturnal and (b) long-lived stable PBLs

The effect of the free flow stability on the PBL height

● LES ● observations

Traditional (local) theory

New non-local theory (Z et al., 2007)

Nocturnal PBL

Polar PBLMarine PBL

Stable PBLs: Conclusions

Non-local nature

due to long-lived structures and/or internal waves

Triggering air pollution

the shallower PBL the heavier air pollution

Sensitivity to thermal impacts

the shallower PBL the stronger microclimate response

triggering global warming in stable PBLs:

in winter- and night-time at Polar and high latitudes

Features of ”scientific revolution”(Tomas Kun, Structure of scientific revolutions, 1962)

TRADITIONAL PARADIGM Forward cascade Fluid flow = mean (regular) + turbulence (chaotic) Applicable to neutrally- and weakly-stratified flows

Crises of traditional theory ALTERNATIVE PARADIGM

Forward (randomisation) and inverse (self-organisation) cascades

Fluid flow = mean (regular) + Kolmogorov’s turbulence (chaotic)

+ anarchic turbulence (with inverse cascade) + organised structures (regular)

NON-LOCAL THEORYSelf-organisation of turbulent convection

Structures and internal waves in stable PBLs Non-local closures Much work to be done

Numerous simple unsolved problems

Towards ”scientific revolution” Marie Curie Chair – PBL (2004-07); ERC-IDEAS PBL-PMES (2009-

13); RU-Gov. Mega-Grant – PBL (2011-13)

Co-authors from > 30 groups / 15 countries Finland (FMI, U-Helsinki); Russia((Nizhny Novgorod State Univ., Obukhov Inst. Atmos. Phys., Rus. State Hydro-met. Univ.) Sweden (MIUU, MISU, SMHI); Norway (NERSC-Bergen); Denmark (RISOE National Lab, DMI-Copenhagen); Israel (Ben-Gurion Univ., Weizmann Inst. Advance Studies); UK (Univ. College London, Brit. Antarctic Sur. Cambridge); USA (Arizona State Univ., Univ. Notre Dame, NCAR, NOAA); Brazil (UNIPAMA, Univ.-Rio Grande, Univ.-Santa Maria); Greece (Nat. Obs., Univ.-Athens); Germany (Univ.-Freiburg); Estonia (Tech. Univ.-Tallinn); Switzerland (SFIT, EPF-Lausanne); France (Univ.-Nantes); Croatia (Univ.-Zagreb)

Thank you Thank you

for your attentionfor your attention

andand

WELCOME TO ADJOIN OUR PARTNERSHIP!