JpGU-AGU Joint Meeting 2017

講演情報

[EE]Eveningポスター発表

セッション記号 A (大気水圏科学) » A-CG 大気水圏科学複合領域・一般

[A-CG46] [EE] 衛星による地球環境観測

2017年5月20日(土) 17:15 〜 18:30 ポスター会場 (国際展示場 7ホール)

[ACG46-P34] JAXA super sites 500: a large footprint ecological monitoring project for satellite validation

*秋津 朋子1奈佐原 顕郎1中路 達郎2吉田 俊也2三枝 信子3小林 秀樹4林 真智5堀 雅裕5本多 嘉明6 (1.筑波大学、2.北海道大学、3.国立環境研究所、4.海洋研究開発機構、5.宇宙航空研究開発機構、6.千葉大学)

キーワード:Satellite validation, Large footprint monitoring, Leaf area index, Above ground biomass, Fraction of absorbed photosynthetically active radiation

JAXA super sites 500 is a large footprint ecological monitoring project for satellite validation. This project has been started from 2013. Its objective is to obtain representing values of leaf area index (LAI), above ground biomass (AGB), and fraction of absorbed photosynthetically active radiation (fAPAR) within the 500 m × 500 m scale, particularly for validation of the ecological products derived by the Global Change Observation Mission-Climate (GCOM-C) satellite, which will be launched in 2017.

LAI, AGB, and fAPAR are essential information for studies of vegetation productivity and carbon cycle. Therefore, these accurate datasets on global and regional scales are needed to be derived by satellite remote sensing. Generally, these datasets have been produced in a satellite sensor’s moderate resolution such as 0.25 km, 0.5 km, or 1 km. To assess their accuracy, in-situ data measured within such spatial resolution is desired. However, such data are rarely available. Accordingly, in previous researches, in-situ data was measured within a smaller area such as 100 m × 100 m and then scaled up to the satellite resolution using higher-resolution imagery. In another case, assuming the larger area was covered with homogeneous vegetation, the in-situ data was directly scaled up to the satellite resolution. However, such scaled-up data includes influences caused by micro-topography and a mixture of different land covers. Thus, the LAI, AGB, and fAPAR products of such satellite sensor’s resolution have been difficult to validate.

In order to overcome this difficulty, we initiated a “JAXA Super Sites 500” project. We have established in-situ observation sites on some typical forest types in East Asia, from temperate to cool ecosystems: deciduous needle-leaf forest (DNF), evergreen needle-leaf forest (ENF), and deciduous broad-leaf forest (DBF). Each site has 500 m × 500 m square research plot in flat topography area. We had carried out pilot studies on each site, and will start full-fledged observations after launching of GCOM-C.

The purpose of this study is to compare their observation methods and sampling designs within this scale, and to evaluate the quality of the in-situ data. Basically, we set five 400 m length parallel line-transects at 100 m intervals in each site. LAI and AGB were measured along these lines. Canopy LAI was measured by three methods: It was measured at 20 m intervals on each line by using LAI-2200/LAI-2000 (LI-COR, USA) and fish-eye digital camera. It was also measured by using litter trap. Understory LAI was measured by two methods: It was measured at 20 m intervals by using LAI-2200 and by using harvesting method. AGB was measured by two methods: It was measured at several points by using an improved Bitterlich’s method. It was also measured within several fixed plots by using a tree census method. Furthermore, we plan to measure fAPAR by using accurate and stable quantum sensors [Akitsu et al., in press].