Turbulent fluxes above different land use areas by airborne measurements Silvia Alfieri (CNR – ISAFOM, Italy) Huilin Chen (MAX PLANK INS., Germany) Dan Dobrovolschi (ANM, Romenia) Monica Górska (Wageningen University, The Netherlands) Petra Kroon (ECN-TUDelft, The Netherlands) Daniel Martinez (UIB, Mallorca).

Research questions 1.Is there a difference in boundary layer height above forest and agriculture land? 2.Is there a difference in meteorological variables above forest and agriculture land? 3.Is there a difference in turbulent fluxes above forest and agriculture land? 4.Is there a difference in entrainment above forest and agriculture land?

Background Climate model uncertainties about boundary layer heights turbulent fluxes entrainment Enhanced entrainment by heterogeneous surface fluxes YesNo Avissar and Schmidt (1998) Fisch et al. (2004) Letzel and Raasch (2003) Patton et al. (2005)

Flight strategy Planned flight pattern Clear sky

Flight strategy Real flight pattern Some clouds

Altitude discussion P SL =1021 hPa P 0 =1013 hPa QNH Standard Altitude 7100ft Example: Standard Altitude=7100ft 7100ft Example: Standard Altitude=6860ft ΔZ=-240ft 6860ft

Results:Boundary layer height Boundary layer height is higher above agriculture. Same stated by Fisch et al. (2004) considering a dry area

Results:Boundary layer height Boundary layer height is higher above agriculture. Same stated by Fisch et al. (2004) considering a dry area

Results: Meteorological variables Potential temperatureWater vapour Potential temperature seems to be lower above agriculture Water vapour seems to be higher above agriculture FAFA

Results:Fluxes Sensible heatLatent heat Sensible heat flux seems to be lower above agriculture Latent heat flux seems to be higher above agriculture

Conclusions 1.Is there a difference in boundary layer height above forest and agriculture land? 2.Is there a difference in meteorological variables above forest and agriculture land? Yes, higher above agriculture Probably yes, lower potential temperature and higher water vapour mixing ratio above agriculture

Conclusions 3.Is there a difference in turbulent fluxes above forest and agriculture land? 4.Is there a difference in entrainment above forest and agriculture land? Yes, slightly lower sensible heat fluxes and higher latent heat fluxes above agriculture. (However more investigations are needed!) To be investigated

Future plans  More thoroughly investigation of –Boundary layer heights –Concentrations –Turbulent fluxes –Entrainment  Trying to write an article

Thank you for listening!