Turbulent fluxes Turbulent fluxes aboveabove different different land use areas by airborne land use areas by airborne

measurementsmeasurementsSilvia Alfieri (CNR – ISAFOM, Italy)Silvia Alfieri (CNR – ISAFOM, Italy)

Huilin Chen (MAX PLANK INS., Germany)Huilin Chen (MAX PLANK INS., Germany)Dan Dobrovolschi (ANM, Romenia)Dan Dobrovolschi (ANM, Romenia)

Monica Górska (Wageningen University, The Netherlands)Monica Górska (Wageningen University, The Netherlands)Petra Kroon (ECN-TUDelft, The Netherlands)Petra Kroon (ECN-TUDelft, The Netherlands)

Daniel Martinez (UIB, Mallorca).Daniel Martinez (UIB, Mallorca).

Research questionsResearch questions

1.1. Is there a difference in Is there a difference in boundary layer heightboundary layer height above above forest and agriculture land?forest and agriculture land?

2.2. Is there a difference in Is there a difference in meteorological variablesmeteorological variables above above forest and agriculture land?forest and agriculture land?

3.3. Is there a difference in Is there a difference in turbulent fluxesturbulent fluxes above forest and above forest and agriculture land?agriculture land?

4.4. Is there a difference in Is there a difference in entrainmententrainment above forest and above forest and agriculture land?agriculture land?

BackgroundBackground

Climate model uncertainties about

• boundary layer heights

• turbulent fluxes

• entrainment

Enhanced entrainment by heterogeneous surface fluxes

Yes No

Avissar and Schmidt (1998)

Fisch et al. (2004)

Letzel and Raasch (2003)

Patton et al. (2005)

Flight strategyFlight strategy

Planned flight pattern

Clear sky

Flight strategyFlight strategy

Real flight pattern

Some clouds

Results:Results: Boundary layer heightBoundary layer height

• Boundary layer height is higher above agriculture.

Same stated by Fisch et al. (2004) considering a dry area

Results:Results: Boundary layer heightBoundary layer height

• Boundary layer height is higher above agriculture.

Same stated by Fisch et al. (2004) considering a dry area

Results: Meteorological variablesResults: Meteorological variablesPotential temperature Water vapour

• Potential temperature seems to be lower above agriculture

• Water vapour seems to be higher above agriculture

F A F A

Results:Results: FluxesFluxesSensible heat Latent heat

• Sensible heat flux seems to be lower above agriculture

• Latent heat flux seems to be higher above agriculture

ConclusionsConclusions

1.1. Is there a difference in Is there a difference in boundary layer heightboundary layer height above above forest and agriculture land?forest and agriculture land?

2.2. Is there a difference in Is there a difference in meteorological variablesmeteorological variables above above forest and agriculture land?forest and agriculture land?

Yes, higher above agriculture

Probably yes, lower potential temperature and higher water vapour mixing ratio above agriculture

ConclusionsConclusions

3.3. Is there a difference in Is there a difference in turbulent fluxesturbulent fluxes above forest and above forest and agriculture land?agriculture land?

4.4. Is there a difference in Is there a difference in entrainment entrainment above forest and above forest and agriculture land?agriculture land?

Yes, slightly lower sensible heat fluxes and higher latent heat fluxes above agriculture. (However more investigations are needed!)

To be investigated

Future plansFuture plans

More thoroughly investigation ofMore thoroughly investigation of– Boundary layer heightsBoundary layer heights– ConcentrationsConcentrations– Turbulent fluxesTurbulent fluxes– EntrainmentEntrainment

Trying to write an article Trying to write an article

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