A sensitivity study of land-air parameterization scheme (LAPS)

Abstract

The sensitivity analysis of LAPS presented in this paper is undertaken to identify those vegetation parameters and input data which, when modified, produce the greatest changes in values of the simulated surface fluxes. A sensitivity study is carried out through a series of one-dimensional simulations for a maize field at the experimental site De Sinderhoeve (The Netherlands). The effect of each input vegetation parameter and initial condition on the surface energy fluxes is independently examined. Its reference value is moved over a range of ±75% and relative variation of latent and sensible heat flux is calculated. Obtained results are confirmed by simple statistical analysis. The values of the average surface fluxes show the greatest sensitivity to the soil moisture initialization, minimal stomatal resistance, fractional area of the ground covered by the vegetation, leaf area density, and the ground roughness length. Changes in values of input parameters and initial conditions cause greater relative variation of the sensible heat than of the latent heat flux.

U ovom radu testirana je šema LAPS na promenu vrednosti morfoloških, fizioloških i fizickih ulaznih parametara, kao i osetljivost šeme na početne vrednosti promenjivih. Korišćenjem podataka sa oglednog polja De Sinderhoeve (Holandija) pokazano je da fluksevi latentne i osetne toplote najviše zavise od početne vrednosti sadržaja vlage u zemljištu, minimalnog otpora stoma, prekrivenosti tla vegetacijom i parametra hrapavosti. Fluks osetne toplote se pokazao kao osetljiviji na promene vrednosti ulaznih parametara i početnih uslova u odnosu na fluks latentne toplote. Dobijeni rezultati su veoma značajni za odredivanje neophodne tačnosti ulaznih veličina i omogućavaju sclektivni pristup dobijanju što tačnijeg seta ulaznih podataka.