多様な地被形態上でのエネルギー収支と空気力学的特性

Abstract

地表面と大気の水、熱の交換過程を明らかにするため, 森林、背丈の低い植生地, 裸地, 積雪の上で超音波風速温度計を用いた微気象観測を行い, エネルギー収支を推定した。エネルギー収支は, 地被形態によって放射収支特性が異なることや, 乱流輸送や土壌水分特性の相違によって変化することが明らかになった。また各地表面での空気力学的抵抗を算出するとともに, 地表面での乱流輸送を支配する地被パラメータである粗度の推定を行った。

In order to clarify the exchanging processes of heat and water vapor between atomospher and various surfaces, meteorological observations using a sonic anemometer-thermometer were carried out on forests, short vegetative fields , bare soil surfaces anda snow surface. Latent heat flux at each place was calculated with the energy budget method using net radiation, sensible heat flux measured by the eddy correlation meathod and heat storage. The characteristics of the energy budget varied with the surface structure and soil surface condition. Sensible heat flux were determined largely by the aerodynamic resistance ruled by the roughness length which are small on the forests, middle on short vegetative fields and large on the bare soil surfaces and the snow surface.