Development of measuring method on forest biomass and canopy roughness in a wide area by using airborne laser altimeter

本研究的目的是建立利用机载激光高度计间接测量森林生物量和冠层表面粗糙度的方法。1995年10月3日，在Ontake山的东南坡进行了第一次野外活动，使用一架直升机，使用波长905nm、频率104Hz的激光高度计，平均海拔3,067米。同时，利用多光谱扫描仪（MSS）对御岳山同一路线的森林类型进行了从下到上的分布：1)人工落叶松林（Larix leptolpis）， 2)天然栎林（Quercus mongolica）， 3)天然冷杉混交林（Tsuga visfolia和Pecea jezoensis）， 4)冷杉林（Abies Mariesii）， 5)桦林（Betula Ermani）和6)高山松林（Pinus Pumila）。在靠近御岳山的赤泽天然柏林（Chamaecyparis obtusa），同样的活动也以飞机照片作为附加项目进行。第二次战役于1996年10月9日在滨湖和滨松市之间进行。一种新型激光高度计，波长1063 nm，频率20000 hz，扫描角度30度，用于研究城市和耕地等复杂地表的通量聚集过程。飞机在不同时间采集了2次MSS数据，并进行了现场观测。所有采集的数据分析如下两点；1)激光测高仪和航空摄影估算的生物量由于地表高度不准确，存在低估的趋势。然而，这些方法对针叶树很有用。2)激光测高仪获得的地表粗糙度对估算复杂地表通量聚集过程具有重要意义。

The objective of this research project is to develop indirect measuring method of forest biomass and surface roughness on canopy by using airborne laser altimeter. The first field campaign was carried out in the south-eastern slope of Mount Ontake with 3,067m a.s.l by a helicopter with laser altimeter with 905nm in wavelength and 104Hz in frequency, in October 3,1995. In the same time, an aircraft has taken MSS (Multi spectral scanner) data at the same course Forest types of Mount Ontake are distributed 1) planted larch forest (Larix leptolpis), 2) natural oak forest (Quercus mongolica), 3) natural fir and spruce mixed forest (Tsuga diversifolia and Pecea jezoensis), 4) fir forest (Abies Mariesii), 5) birch forest (Betula Ermani) and 6) high-mountain pine forest (Pinus Pumila) from lower to upper. In Akasawa natural cypress forest (Chamaecyparis obtusa) located close to Mount Ontake, the same campaign was also carried out with airplane photograph as an additional item. The second campaign was done in a line between Lake Hamana-ko and Hamamatsu-city in October 9,1996. A new laser altimeter with 1,063nm in wavelength, 20,000Hz in frequency and 30 degree in scanning angle, for investigating an aggregation process of fluxes in complicated land surface including urban and cultivated area. Two MSS data in different time were taken by an aircraft and the in situ observation was also carried out. All of data taken were analyzed as following two points ;1) Biomass estimated by two methods, those are laser altimeter and aerial photograph, has a tendency of underestimation because of the inaccuracy of height in ground surface. Those methods, however, are useful for needle trees.2) Surface roughness gained by laser altimeter is very useful for estimating aggregation process of fluxes in complicated land surface.