In situ observations reveal how spectral reflectance responds to growing season phenology of an open evergreen forest in Alaska

Kobayashi, Hideki*; Nagai, Shin*; Kim, Y.*; Yan, W.*; Ikeda, Kyoko*; Ikawa, Hiroki*; Nagano, Hirohiko; Suzuki, Rikie*

Remote Sensing, 10(7), p.1071_1 - 1071_19, 2018/07

https://doi.org/10.3390/rs10071071

Plant phenology timings, such as spring green-up and autumn senescence, are essential state information characterizing biological responses and terrestrial carbon cycles. Current efforts for the in situ reflectance measurements are not enough to obtain the exact interpretation of how seasonal spectral signature responds to phenological stages in boreal evergreen needleleaf forests. This study shows the first in situ continuous measurements of canopy scale (overstory + understory) and understory spectral reflectance and vegetation index in an open boreal forest in interior Alaska. Two visible and near infrared spectroradiometer systems were installed at the top of the observation tower and the forest understory, and spectral reflectance measurements were performed in 10 min intervals from early spring to late autumn. We found that canopy scale normalized difference vegetation index (NDVI) varied with the solar zenith angle. On the other hand, NDVI of understory plants was less sensitive to the solar zenith angle. Due to the influence of the solar geometry, the annual maximum canopy NDVI observed in the morning satellite overpass time (10-11 am) shifted to the spring direction compared with the standardized NDVI by the fixed solar zenith angle range (60-70 degree). We also found that the in situ NDVI time-series had a month-long high NDVI plateau in autumn, which was completely out of photosynthetically active periods when compared with eddy covariance net ecosystem exchange measurements. The result suggests that the onset of an autumn high NDVI plateau is likely to be the end of the growing season. In this way, our spectral measurements can serve as baseline information for the development and validation of satellite-based phenology algorithms in the northern high latitudes.

TANPOPO: astrobiology exposure and micrometeoroid capture experiments; For understanding survival possibility of trans-space migration of microorganisms

Yokobori, Shinichi*; Yang, Y.*; Fujisaki, Kenta*; Kawaguchi, Yuko*; Kobayashi, Kensei*; Hashimoto, Hirofumi*; Kawai, Hideyuki*; Mita, Hajime*; Narumi, Issei; Okudaira, Kyoko*; et al.

no journal, , 

no abstracts in English

TANPOPO (Astrobiology Exposure and Micrometeoroid Capture Experiments on ISS-JEM KIBO); Investigation of possible survivability of microorganisms in space

Yokobori, Shinichi*; Fujisaki, Kenta*; Kawaguchi, Yuko*; Yang, Y.*; Fushimi, Hidehiko*; Hashimoto, Hirofumi*; Yamashita, Masamichi*; Yano, Hajime*; Okudaira, Kyoko*; Hayashi, Nobuhiro*; et al.

no journal, , 

no abstracts in English

Microbe space exposure experiment at International Space Station (ISS) proposed in "Tanpopo" mission

Yokobori, Shinichi*; Yang, Y.*; Sugino, Tomohiro*; Kawaguchi, Yuko*; Fushimi, Hidehiko*; Narumi, Issei; Hashimoto, Hirofumi*; Hayashi, Nobuhiro*; Kawai, Hideyuki*; Kobayashi, Kensei*; et al.

no journal, , 

Crystal structures of two coupled enzymes accomplishing high-efficient biochemical synthesis of trehalose

Okazaki, Nobuo; Tamada, Taro; Miura, Yutaka*; Feese, M. D.*; Kato, Masaru*; Komeda, Toshihiro*; Takehara, Kyoko*; Kobayashi, Kazuo*; Kondo, Keiji*; Kuroki, Ryota

no journal, , 

The crystal structure of glycosyltrehalose synthase (GTSase) from the hyperthermophilic archaeum Sulfolobus shibatae DSM5389 has been determined to 2.3 A resolution by X-ray crystallography. GTSase converts the glucosidic bond between the last two glucose residues of amylose from an alpha-1,4 bond to an alpha-1,1 bond, making a non-reducing glycosyl trehaloside in the first step of the biosynthesis of trehalose. The structure of GTSase can be divided into five domains. The central domain has the (beta/alpha)8 barrel fold which is conserved in the alpha-amylase family as the catalytic domain. Three invariant catalytic carboxylic amino acids in the alpha-amylase family are also found in GTSase at positions Asp241, Glu269 and Asp460 in the (beta/alpha)8 domain. Our previous study with KM1-GTSase has been shown that the maltooligosaccharides are converted to glycosyltrehalose by an intramolecular transglycosylation mechanism.

The Microbe capture experiment in space; Fluorescence microscopic detection of microbes captured by aerogel

Sugino, Tomohiro*; Yokobori, Shinichi*; Yang, Y.*; Kawaguchi, Yuko*; Hasegawa, Sunao*; Hashimoto, Hirofumi*; Imai, Eiichi*; Okudaira, Kyoko*; Kawai, Hideyuki*; Tabata, Makoto*; et al.

no journal, , 

Capture and space exposure experiments of microorganisms on the ISS orbit proposed in "TANPOPO" mission

Yokobori, Shinichi*; Yang, Y.*; Kawaguchi, Yuko*; Sugino, Tomohiro*; Takahashi, Yuta*; Narumi, Issei; Nakagawa, Kazumichi*; Tabata, Makoto*; Kobayashi, Kensei*; Marumo, Katsumi*; et al.

no journal, , 

TANPOPO: astrobiology exposure and micrometeoroid capture experiments; Proposed experiments at the exposure facility of ISS-JEM

Yokobori, Shinichi*; Hashimoto, Hirofumi*; Hayashi, Nobuhiro*; Imai, Eiichi*; Kawai, Hideyuki*; Kobayashi, Kensei*; Mita, Hajime*; Nakagawa, Kazumichi*; Narumi, Issei; Okudaira, Kyoko*; et al.

no journal, , 

Current status of preparation of TANPOPO mission (astrobiology exposure and micrometeoroid capture experiments) and investigation of survivability of microbes in space

Yokobori, Shinichi*; Kawaguchi, Yuko*; Yang, Y.*; Kawashiri, Narutoshi*; Shiraishi, Keisuke*; Shimizu, Yasuyuki*; Takahashi, Yuta*; Sugino, Tomohiro*; Narumi, Issei; Sato, Katsuya; et al.

no journal, , 

no abstracts in English

Experiments on microbes in TANPOPO mission on the International Space Station

Yokobori, Shinichi*; Kawaguchi, Yuko*; Harada, Miyu*; Murano, Yuka*; Tomita, Kaori*; Hayashi, Nobuhiro*; Tabata, Makoto*; Kawai, Hideyuki*; Okudaira, Kyoko*; Imai, Eiichi*; et al.

no journal, , 

no abstracts in English