Surface roughness parameterization in heterogeneous land surfaces
PhD project
| Graduate student | Kitsiri Weligepolage |
| Promotors | Prof. Dr. Z. Su |
| Co-promotors | Dr. A.S.M. Gieske |
| Partner | |
| Timeline | June 2006 - June 2010 |
| Sources of funding | ITC research fund |
Remote sensing methods to estimate turbulent fluxes at the surface are still in a developing stage and, there exist some problematic areas. One such example is the lack of robust methods to parameterize the surface roughness lengths; both the momentum roughness length (z0m) and the thermal roughness length (z0h) particularly over heterogeneous surfaces.
My research aims to develop a physically based parameterization methodology which will be applied for the estimation of the roughness length for momentum and heat transfer focussing on the operational application to large scale data. Furthermore, obtaining the full advantage of the directional radiometric observations, it is intended to develop new algorithms for surface energy balance, incorporating the improved parameterization to estimate resistance for momentum and heat transfer.
This research will mainly focus on parameterizing the roughness of heterogeneous vegetative surfaces such as agricultural lands and forested areas. The data for the study will be from two field campaigns; EAGLE 2006 conducted in the central part of the Netherlands and AGRISAR 2006 field experiment conducted in North-East Germany.
The campaign areas of EAGLE 2006 mainly consist of pasture lands and planted forests grown up to a height over 30m while the test area of AGRISAR 2006 field campaign comprises of partly irrigated agricultural plots, ranging from completely bare soil to fully vegetated parcels with canopy heights from several centimeter up to one and a half meter.
The study will integrate various micrometeorological observations, surface flux measurements and ground based three dimensional laser scanned data in combination with high resolution air-borne data and satellite images acquired during the above field campaigns to critically evaluate the aerodynamic and thermodynamic characteristics of the aforementioned land surface types at different scales. Advancement on this direction will be used to develop and improve surface roughness parameterization schemes which will be eventually incorporated to existing remote sensing surface energy balance algorithms to estimate the regionally distributed surface fluxes over heterogeneous landscapes.