1 / 12

Land atmosphere interaction –conceptual model exercise

Land atmosphere interaction –conceptual model exercise. Bart van den Hurk (KNMI/IMAU). Last week. Explore the thermal coupling For instance : Look for a relationship between u and skin conductivity that has roughly the same T a /t using  air = 1 (switching off radiation response)

trula
Download Presentation

Land atmosphere interaction –conceptual model exercise

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Land atmosphere interaction –conceptual model exercise Bart van den Hurk (KNMI/IMAU) Example of conceptual land-atmosphere model

  2. Last week • Explore the thermal coupling • For instance: Look for a relationship between u and skin conductivity that has roughly the same Ta/t using • air = 1 (switching off radiation response) • Ta-Tsoil = 10K (initial gradient) Example of conceptual land-atmosphere model

  3. Layout of a conceptual land-atmosphere hydrology model Fin Fout P R E ds/dt L Example of conceptual land-atmosphere model

  4. Layout of a conceptual land-atmosphere hydrology model Stochastic forcing P = 0.5 g(s) (uw/L + E) uw / L + s residual R = ePsr E = Epot sc • = evaporative fraction Q* = net radiation • = precip.efficiency • = runoff efficiency D = soil depth L = horizontal length scale uw = wind speed  atm.moisture r, c = coefficients ds/dt = (P-E-R)/D Example of conceptual land-atmosphere model

  5. Stochastic Differential Eq (SDE) stochastic (forcing) term Discretization and rewriting leads to G = drift term (gains and losses by P, E, R) gr = random term r = Gaussian number with variance 1 and mean 0 Example of conceptual land-atmosphere model

  6. Column structure Fout = Fin Fin +  Fout = Fin Fout = Fin P P P … E E E R R R ds/dt ds/dt ds/dt i=n i=1 i=2 Example of conceptual land-atmosphere model

  7. Parameterization of , E, R • Precipitation efficiency (s) = a s + b • Evaporation E(s) = Epot sc Epot(i) = linear interpolation between Epot(1) and Epot(n) i = column number, n = nr of columns • Runoff R = P sr Example of conceptual land-atmosphere model

  8. Code list weak / strong REAL RAEFF 0.0 / 0.2 ! coefficient A in PrecEff = A s + B REAL RBEFF 0.3 / 0.2 ! coefficient B in PrecEff = A s + B REAL RUW 200. ! advection U x W (m/s kg/m2 = kg/m s) REAL RLEN 1000000 ! horizontal length scale (m) REAL RSDEV 0.1 ! Standard deviation of stochastic term ! on UW/L (fraction) REAL RAEPOT 1. ! Epot at first column (m/yr) REAL RBEPOT 2. ! Epot at last column (m/yr) REAL RECOF 0.5 ! Coefficient c in E = Epot s^c REAL RR 0.1 ! Coefficient r in R = e P s^r REAL REPSIL 0.1 ! Coefficient e in R = e P s^r (runoff ! efficiency) REAL RSDEP 0.5 ! Storage reseroir depth (m) REAL RTIME 0.0001 ! Time step length (yr) REAL RZCR 0.01 ! soil saturation below which red noise is ! restricted to postive values REAL RSTMAX 1 ! clipping value of zst REAL RYEAR 10 ! Number of years to simulate INTEGER NCOL 10 ! nr of adjacent columns INTEGER NPPSTEP 1000 ! output interval (nr of steps) Example of conceptual land-atmosphere model

  9. Weak coupling between s and  Example of conceptual land-atmosphere model

  10. Strong coupling between s and  Example of conceptual land-atmosphere model

  11. Soil moisture evolution weak strong Example of conceptual land-atmosphere model

  12. More information • Bart van den Hurk • hurkvd@knmi.nl • www.knmi.nl/~hurkvd Example of conceptual land-atmosphere model

More Related