Phenological Eyes Network (PEN) --- Connecting Satellite Remote Sensing to the Ground-Level Ecosystems --- contact: What does PEN stand for?

Leaflet: PDF / PPT / JPEG (page1, page2, page3, page4)
Review article in AsiaFlux Newsletter (2007)

Note: Because many of the original information is in Japanese, you would obtain newer or more detailed infromation on Japanese main page.

News

UAK site was established with a support by JAMSTEC-IARC project.
A new article referring to PEN in FluxLetter (p. 13-).
2005.2.27-7.6:We apologize that PEN mail-address for information and inquiry was out of order in this period.
2004.9.8:TFS site was encountered with Typhoon attack! The system of this site has been stoped.


old news

Data of PEN

ID	Site name	Type	Data	Note
AHS	Alice Holt	DBF	recent original summary log	2009-, ADFC
AI7	AIST 7th Building	urban	recent original summary log	2004 only. Sky ADFC only.
GDK	Gwangneung	DBF	recent original summary log	2009-, ADFC, HSSR
FHK	Fuji-Hokuroku	DNF	recent original summary log	2005-, ADFC, HSSR, SP. Managed by NIES and AIST
KEW	Kiryu Experimental Watershed	ENF	recent original summary log	2004-, ADFC, HSSR.
LBR	Lambir Hills	EBF	recent original summary log	2009-, ADFC.
MSE	Mase	rice paddy	recent original summary log	2005-, ADFC, HSSR. Managed by NIAES and U. Tsukuba
MTK	Mt. Tsukuba	mix forest	recent original summary log	2008-, ADFC; Tsukuba
SSP	Spasskaya Pad	DNF		1997/08/25-2000/10/15, by Rikie Suzuki, JAMSTEC
RHN	RIHN	urban	recent original summary log	2005-2006. Sky ADFC only.
SGD	Sugadaira	grassland	recent original summary log	2005-, ADFC. Managed by U. Tsukuba.
SHA	Seoul Heonilleung Alnus Forest	Decidious forest	recent original summary log	2010-, ADFC. Managed by U. Korea.
TFS	Tomakomai Flux Site	DNF	recent original summary log	2004. Destroyed by a typhoon. Managed by NIES.
TGF	TERC Grass Field	grassland	recent original summary log	2003-, ADFC, HSSR, SP. Managed by U. Tsukuba.
TKC	Takayama Conifer Flux Site	ENF	recent original summary log	2007-, ADFC, HSSR. Managed by Gifu U.
TKY	Takayama Flux Site	DBF	recent original summary log	2003-, ADFC, HSSR, SP. Managed by Gifu U., U. Tsukuba, and AIST.
UAK	University of Alasla Fairbanks	ECF	recent original summary log	2010-, ADFC. Managed by JAMSTEC and IARC.

3-character ID is taken from JapanFlux rule.

* Acronyms: ADFC: Automatic Digital Fisheye Camera AIST: National Institute of Advanced Industrial Science and Technology DBF: deciduous broadleaf forest DNF: deciduous needleleaf forest (in our case, larch forest) ENF: evergreen needleleaf forest HSSR: Hemi-Spherical Spectral Radiometer NIAES: National Institute for Agro-Environmental Sciences NIES: National Institute for Environmental Studies RIHN: Research Institute for Humanity and Nature SP: SunPhotometer (Skyradiometer) TERC: Terrestrial Environment Research Center, Univ. Tsukuba

* Map of PEN sites

Data of Collaborating projects

"Gamo's Eye" Fully Automated Phenology Tele-Monitor ... by Drs. Gamo and Maeda in AIST

PHENOLOGICAL PHOTOGRAPHS OF SIBERIAN LARCH FOREST FROM 1997 TO 2000 ... by Dr. Rikie SUZUKI in JAMSTEC

What is PEN?

Satellite remote sensing (RS) is a strong methodology in the study of terrestrial ecosystems. For example, RS is used in scaling up of the ground measurements of carbon flux, water flux, biomass, etc. from a site scale to a regional or global scale. RS provides numerical regional ecological models with information for initial conditions, boundary conditions, and validation. For the sake of it, various new satellite sensors have been designed and launched. They are now delivering a lot of high-level products regarding to the terrestrial ecology, such as new vegetation indices, LAI, FPAR, phenology, GPP, and NPP.

However, in the ecological standpoint, these RS methodology has not enough checked or validated on the ground level. Because an essential characteristics of ecosystem is its dynamism (especially the seasonal change, or "phenology"), the accuracy, quality, and interpretation of the RS data should be also studied dynamically. For the sake of it, a stable, continuous, long-term, and multi-ecosystem ground validation network is desired. Of course, the flux observation networks such as AsiaFlux have potential to contribute to it. However, because RS observes vegetation's optical characteristics rather than carbon or heat flux, we need to include optical (spectral) observation in the validation of ecological RS. We believe that the ecological interpretation of RS data is possible only if it is based on a careful theoretical and experimental study of the relationships between optical characteristics and ecological structure (or function), using the quality-controlled RS data considering the relevant noise factors such as cloud contamination or atmospheric aerosols.

With this background stated above, we have started the "Phenological Eyes Network (PEN; Tsuchida et al., 2005)." PEN is a network of ground observatories for long-term automatic observation of the vegetation dynamics (phenology), vegetation's optical properties (such as spectral reflectance), and the atmospheric optical properties (such as aerosol optical thickness). Most PEN ground sites have been set up at the AsiaFlux sites. The collaboration of PEN and AsiaFlux is critically important in the interpretation of the optical signals captured by RS in terms of ecology (especially the terrestrial carbon/water cycles).

PEN's scientific targets

phenology
cloud coverage
photosynthesis (LUE, FPAR and PAR)
leaf area index (LAI)
validation, calibration, and assimilation of satellite data
radiative temperature and its directional dependency
radiative transfer models / carbon and water cycle models

PEN has been supported by the Global Environment Research Fund (S-1: Integrated Study for Terrestrial Carbon Management of Asia in the 21st Century Based on Scientific Advancement) of the Ministry of Environment of Japan.

Observation system

Because the goal of PEN is to collect long-term quality-controlled multi-site data, the main instruments should be stable, robust, and low-cost. Based on this principle, we selected and designed the following three types of instruments: the Automatic-capturing Digital Fisheye Camera (ADFC), the HemiSpherical Spectro-Radiometer (HSSR), and the sunphotometer (SP).

ADFC

ADFC is a combination of a high-quality digital camera (Nikon CoolPix series), a fish-eye lens (Nikon FC-E8), a water-proof housing case, and a control system with a personal computer. It captures images of the sky, the canopy from above and below, the forest floor, and shoots of typical species with short intervals (2 minutes to 24 hours, depending on the target). These images provides information about cloud condition at the satellite's observation, vegetation phenology, snow pack, tree cover, and LAI.

HSSR

HSSR is a hyper-spectral radiometer in the visible and near-infrared region (MS-700 of Eko Instruments Co. or PGP-100 of Prede Co.). In order to catch both incoming and reflecting radiation with a single radiometer, we developed a computer-controlled rotating stage in collaboration with Hayasaka Rikoh Co. If the HSSR is mounted on the rotating stage, it can be directed upward and downward consecutively with a short interval of time at a same position. Thus we can obtain the spectral features of the vegetation canopy with fine-temporal and fine-spectral resolution. By using such data, we can check the spectral observation of RS. Moreover, we can simulate various types of spectral indices (such as NDVI, EVI, PRI) with arbitrary spectral response of every specific satellite sensors.

SP

SP is a spectral radiometer with a small field-of-view and pointing functionality. We use POM-02 of Prede Co. We can estimate optical properties of the atmosphere which are needed for atmospheric correction of the RS data. It can provide quantitative information about atmospheric pollution or aerosol dust (such as the Yellow Sands), both of which may have some direct or indirect impacts on the ecosystems.

Other sensors

In addition to the above-mentioned main instruments, in some sites, we are making observation of environmental ecophysiological properties including incoming PAR (direct and diffuse), transmitting PAR, leaf phenology, LAI (LAI-2000, fisheye image, laser profiler, and litter trap), leaf-level optics, leaf-level physiology (LI-6400, pigments, C/N, LMA).

Details on the system (in Japanese)

Data management system

Most data taken by these sites have been stored in the PEN's database server. The original data are open to the PEN community member (anybody can join if they want) and the summary or edited data are open to the public.

• Nishida, K. (2007): Phenological Eyes Network (PEN) --- A validation network for remote sensing of the terrestrial ecosystems. AsiaFlux Newsletter, 21, pp. 9-13. (PDF)
• Nakaji, T., Ide, R., Takagi, K., Kosugi, Y., Ohkubo, S., Nishida, K., Saigusa, N., and Oguma, H. (2008) Utility of spectral vegetation indices for estimation of light conversion efficiency in coniferous forests in Japan. Agricultural and Forest Meteorology, 148, pp. 776-787, doi:10.1016/j.agrformet.2007.11.006.
• Nasahara, K. N., H. Muraoka, S. Nagai, H. Mikami (2008): Vertical integration of leaf area index in a Japanese deciduous broad-leaved forest. Agricultural and Forest Meteorology, 148/6-7, pp. 1136-1146, doi:10.1016/j.agrformet.2008.02.011.
• Wingate, L., Richardson, A. D., Weltzin, J. F., Nasahara, K. N., and Grace, J. (2008): Keeping an eye on the carbon balance: linking canopy development and net ecosystem exchange using a webcam. FluxLetter 1(2), pp. 14-17. [link]
• Motohka, T., K. N. Nasahara, A. Miyata, M. Mano, and S. Tsuchida (2009): Evaluation of optical satellite remote sensing for rice paddy phenology in monsoon Asia using continuous in-situ dataset. International Journal of Remote Sensing, 30(17), 4343 - 4357, DOI: 10.1080/01431160802549369. [abstract]
• Yamamoto H., Kamei, A., Nakamura, R., Yamamoto, N., Iwao, K., Tsuchida, S., Tanaka, Y., and Sekiguchi, S. (2009) : Field Sensor Virtual Organization Integrated with Satellite Data on a Geo Grid. Data Science Journal, 8 , pp.IGY21-IGY31.(PDF)
• Nagai, S., K. N. Nasahara, H. Muraoka, T. Akiyama, S. Tsuchida (2010): Field experiments to test the use of the normalized difference vegetation index for phenology detection. Agricultural and Forest Meteorology, 150: 152-160.
• Muraoka, H., N. Saigusa, K. N. Nasahara, H. Noda, J. Yoshino, T. M. Saitoh, S. Nagai, S. Murayama and H. Koizumi (2010): Effects of seasonal and interannual variations in leaf photosynthesis and canopy leaf area index on gross primary production of a cool-temperate deciduous broadleaf forest in Takayama, Japan. Journal of Plant Research, 122, 3-20, DOI:10.1007/s10265-008-0188-2.
• Nagai, S., N. Saigusa, H. Muraoka and K. N. Nasahara (2010): What makes the satellite-based EVI-GPP relationship unclear? Ecological Research, 25: 359-365.
• Kume, A., Nasahara, K. N., Nagai, S., and Muraoka, H. (2010): The ratio of transmitted near-infrared radiation to photosynthetically active radiation (PAR) increases in proportion to the adsorbed PAR in the canopy. Journal of Plant Research, DOI 10.1007/s10265-010-0346-1.

• Tsuchida, S., Nishida, K., Oguma, H., and Kawato, W. (2004): The detecting offset of greeness by water and chlorophyll indices for phenological eyes network (PEN). Hyper Spectrum Remote Sensing Workshop, Tokyo.
• Nishida, K., Tsuchida, S., Oguma, H., and Kawato, W. (2004): Combination of ecophysiological remote sensing and an ecosystem - radiative transfer model and its validation with a ground observation system. The 6th International Symposium on Plant Response to Air Pollution and Global Changes (APGC), Oct. 19-22, Tsukuba.
• Nakaji AGU
• Nishida, K. (2005): Influence of stems and branches on the reflectance and ecophysiological process of forest canopy. 1st International Symposium of the 21st Century COE Program "Satellite Ecology," Oct. 14, 2005, Gifu Univ., Japan.
• Iwao, K., Tsuchida, S., Nishida, K., Oguma, H., Iwasaki, A., and Kawato, W. (2005): Phenological Eyes Network ... Ground-based measurement for remote sensing studies. 1st International Symposium of the 21st Century COE Program "Satellite Ecology," Oct. 14, 2005, Gifu Univ., Japan. (poster)
• Nishida, K. (2006): Phenological Eyes Network (PEN): A Ground network for satellite ecological data validation. Global Vegetation Workshop 2006, August 7-10, 2006, University of Montana (poster).
• Nagai, S., Ishihara, M., Nasahara, K. N., Muraoka, H. (2008) Detecting start date of bud-burst and end date of leaf-falling by remote-sensing in a cool-temperate deciduous broad-leaved forest. A3 Workshop, Seoul, 2008/02
• Mikami, H., Matsushita, B., Fukushima, T., Nasahara, K. N. (2008) A continuous measurement of leaf area index using automatic-capturing digital camera: Seasonal variation in a deciduous broadleaf forest. A3 Workshop, Seoul, 2008/02
• Ishihara, M., Nagai, S., Nasahara, K. N., Akiyama, T. (2008) A phenology monitoring method using digital images of the deciduous broad-leaved forest in Takayama. A3 Workshop, Seoul, 2008/02
• Ishihara, M., S. Nagai, K.N. Nasahara, T. Akiyama (2008): Observation of annual phenology pattern using digital images in a deciduous broad-leaved forest. 2nd International Symposium of 21st Century COE Program "Satellite Ecology" at Gifu University, 2008/07/30
• Nasahara, K. N., H. Muraoka (2008): Leaf-to-canopy upscaling of optical signals and physiology of forest canopy. 2nd International Symposium of 21st Century COE Program "Satellite Ecology" at Gifu University, 2008/08/01.
• Lisa Wingate, Andrew D. Richardson, Kenlo N. Nasahara, Jake F. Weltzin, John Grace and the FLUXNET webcam network: Keeping an eye on the carbon balance: linking canopy development and net ecosystem exchange using an international webcam network. 2009/04 EGU General Assembly 2009, Vienna.
• Motohka, T., Nasahara, K. N. (2009): Recent progress of Phenological Eyes Network (PEN). A3 Jinju workshop, 2009/4/20-24, Korea.
• Noda, H., H. Muraoka, K. N. Nasahara and N, Saigusa (2009) Phenology of leaf photosynthetic properties in a cool-temperate deciduous broadleaf forest in Takayama, Japan. AnsiaFlux Workshop 2009, Oct., Sapporo. (poster)
• Motohka, T. and Nasahara, K. N. (2009): New method for detection of vegetation phenology with satellite remote sensing: "GRVI-method". AsiaFlux Workshop 2009, 2009/10/27, Sapporo. (poster)
• Mizunuma, T., Koyanagi, T., Nasahara, K.N., Mencuccini, M., and Grace, J. (2009) The optimal colour index for the photographic recording of leaf phenology. AsiaFlux Workshop 2009, 2009/10/27, Sapporo. (poster)
• S. Ninsawat, R. Nakamura, H. Yamamoto, A. Kamei, and S. Tsuchida(2009):Validation of Satellite Image with Ground Sensor Network based on OGC Web Services Framework, FOSS4G 2009 Conference, Sydney, Australia, Oct. 20-23.
• A. Kamei, S. Ninsawat, H. Yamamoto, R. Nakamura, S. Tsuchida, and T. Maeda(2009):Integrated system of satellite and field data for mapping of gross primary production,AsiaFlux Workshop 2009 Integrating Cross-scale Ecosystem Knowledge: Bridges and Barriers, Sapporo, Japan, Oct. 27-29 (poster).
• S. Ninsawat(2009):Federating Satellite data and Sensor data, Geo International Workshop, The 17th Pacific Rim Application and Grid Middleware Assembly (PRAGMA), Hanoi, Vietnam, Oct. 28.
• Nagai, S (2010): Comprehensive ground observation network connecting satellite remote-sensing with in situ ecosystem observations: Phenological Eyes Network (PEN). International Conference on Phenology: Plant ecology and diversity. Edinburgh, 2010/04.
• Nagai, S (2010): Phenological Eyes Network (PEN). An International Workshop on the Validation of Satellite-based Land Surface Phenology Products. Dublin, 2010/06.