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Fluxes

Fluxes. Mark A. Bourassa COAPS & EOAS, Florida State University, bourassa@coaps.fsu.edu. With input from:

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Fluxes

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  1. Fluxes Mark A. Bourassa COAPS & EOAS, Florida State University, bourassa@coaps.fsu.edu With input from: USCLIVAR Working Group on High-Latitude Fluxes:Ed Andreas, Cecelia Bitz, Dave Carlson, IvanaCerovecki, Meghan Cronin‏, Will Drennan, Chris Fairall, Sarah Gille (co-chair)‏, Ross Hoffman, Gudrun Magnusdotti, Rachel Pinker, Ian Renfrew‏, Mark Serreze, Kevin Speer, Lynne Talley, Gary Wick Fluxes from Space: Carol Anne Clayson, Sarah Gille, Darren Jackson, Brent Roberts, Joel Scott, Shawn Smith, Gary Wick Ocean Modeling and Reanalysis Comparison: Dmitry Dukhovskoy and Paul Hughes

  2. Distribution of SHF is Inconsistent Among Products

  3. Selected Motivations • Differences between flux products are much too large • Differences are reduced in modern products (Bourassa et al.) • It has been suggested that surface fluxes play a large role in several aspects of Arctic ice melt and growth • Links to oceanic deep convection • Deep water formation in the Southern Ocean might be influenced by fluxes – particularly latent heat flux (Speer) • Indian ocean dynamics very sensitive to surface fluxes • Large latent heat flux over water contributes to both the energy and water cycles • Observed changes in Hadley and Walker circulation should be associated with changes in surface fluxes • SST gradients near western boundary currents estimated to cause monthly averaged regional changes in latent heat flux of >30Wm-2 • Surface moisture convergence linked to some clouds?

  4. Accuracy Requirements • Fluxes are estimated through bulk formulas • Goal <5Wm-2 bias in sum of latent and sensible heat flux • Goal assessments were done by Chris Fairall • Wind spd: 0.4 m/s threshold; 0.2 m/s goal; 0.1 m/s outstanding • SST: 0.2 C threshold; 0.1 C goal; ? outstanding • Air Temp: 0.2 C threshold; 0.1 C goal; ? Outstanding • Spec humidity: 0.6 g/kg threshold; 0.3 g/kg goal; ? Outstanding • Goals on random error are not clear, as they are more relevant to short-lived and smaller area forcing • For the larger scale applications, sampling will overcome random error. • Both of the above statements assume that there is no cross correlation of errors between variables.

  5. Comparison of Two Retrieval Techniques • Blue – Roberts et al. (SeaFlux) • Red – Jackson and Wick • Need more data to improve extremes

  6. Discussion

  7. The period for comparison (for which all products are available) is 03/1992 through 12/2000. • Black line is the track from Ryan Maue’s data set • Lack of retrieval in areas with too much rain

  8. Input to Bulk Fluxes

  9. Exceedance Probability (U>17 m/s) , winter 2005-2007 CCMP ASR Greenland 0.15 0.12 0.1 CFSR NCEPR 0.08 Greenland Greenland 0.05 0.03 0.004

  10. Evaluation of Satellite Retrievals of 10m Ta and Qa • Comparison to research vessel observations from SAMOS

  11. Progress: Flux Accuracies and Applications 50 Wm-2 10 Wm-2 100 years 5 Wm-2 Climate Change 1 Wm-2 10 years 0.1 Wm-2 Ice Sheet Evolution 0.01 Nm-2 Annual Ice Mass Budget Unknown 1 year Annual Ocean Heat Flux Open Ocean Upwelling Upper Ocean Heat Content & NH Hurricane Activity 1 month Stress for CO2 Fluxes Dense Water Formation Mesoscale andshorter scalephysical-biologicalInteraction Atm. Rossby Wave Breaking Ocean Eddies and Fronts 1 week Ice Breakup Polynyas Shelf Processes 1 day Leads Conv. Clouds &Precip NWP High ImpactWeather 1 hour 10m 100m 1km 10km 100km 103km 104km 105km

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