Japan Geoscience Union Meeting 2014

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International Session (Oral)

Symbol A (Atmospheric, Ocean, and Environmental Sciences) » A-CG Complex & General

[A-CG06_29PM2] Satellite Earth Environment Observation

Tue. Apr 29, 2014 4:15 PM - 6:00 PM 315 (3F)

Convener:*Riko Oki(Japan Aerospace Exploration Agency), Yoshiaki Honda(Chiba University, Center for Environmental), Kenlo Nishida Nasahara(Institute of Agricultural and Forest Engineering, University of Tsukuba), Takashi Nakajima(Tokai University Department of Network and Computer Engineering, School of Information and Design Engineering), Taikan Oki(Institute of Industrial Science, The University of Tokyo), Yokota Tatsuya(Center for Global Environmental Research, National Institute for Environmental Studies), Yukari N. Takayabu(Atmosphere and Ocean Research Institute(AORI), The University of Tokyo), Hiroshi Murakami(Earth Observation Research Center, Japan Aerospace Exploration Agency), Hajime Okamoto(Research Institute for Applied Mechanics,Kyushu University), Chair:Hiroshi Murakami(Earth Observation Research Center, Japan Aerospace Exploration Agency), Kenlo Nasahara(Faculty of Life and Environmental Sciences, University of Tsukuba)

4:45 PM - 5:00 PM

[ACG06-30] Ocean primary production algorithm for the GCOM-C1/SGLI

*Toru HIRAWAKE1, Ryosuke FUTSUKI1, Katuhito SHINMYO1, Shintaro TAKAO2, Amane FUJIWARA3, Sei-ichi SAITOH1 (1.Faculty/Graduate School of Fisheries Sciences, Hokkaido University, 2.Faculty of Environmental Earth Science, Hokkaido University, 3.National Institute of Polar Research)

Keywords:primary production, phytoplankton, absorption coefficient, GCOM-C, SGLI

One of the objectives of second-generation global imager (SGLI) on the earth observation satellite, Global Change Observation Mission 1st-Climate (GCOM-C1) is to understand the global carbon cycle. Therefore, estimation of column integrated daily net primary production (PPeu) as carbon assimilation by photosynthesis of phytoplankton in the ocean is essential for the objective of SGLI/GCOM-C1 project. Most of the algorithms developed in the past used chlorophyll a (chl a) concentration. However, estimation of chl a concentration from satellite data has uncertainty due to the effect of pigment packaging that leads to underestimation, and the interference of colored dissolved organic matter (CDOM) which leads to overestimation. Another uncertainty is derivation of photosynthetic rate of phytoplankton. Although the vertically generalized productivity model (VGPM) which is one of the frequently used algorithms expressed the maximal photosynthetic rate (P^opt) as a function of sea surface temperature (SST), the SST derived P^opt had large error, particularly in the polar waters. Furthermore, discussion on the effect of global warming to primary productivity in the ocean using satellite data is facilitated, if the photosynthetic rate is an independent parameter on the SST. To reduce these issues, light absorption coefficient of phytoplankton (aph) was used in the algorithm for SGLI/GCOM-C1; product of P^opt and chl a in the VGPM, which means productivity at the depth with the maximal photosynthetic rate within a water column, was expressed by photosynthetic available radiation (PAR) absorbed in phytoplankton. In situ primary production and optical data to develop the algorithm were measured in the North Pacific, Japan Sea, East China Sea, Southern Ocean, Chukchi Sea (Arctic Ocean), Bering Sea. Additional datasets of the Bermuda Atlantic Time-series Study (BATS), Hawaii Ocean Time-series (HOT) and The California Cooperative Oceanic Fisheries Investigations (CalCOFI) were also obtained for the development and validation of the algorithm. Accuracy in the estimation of product of P^opt and chl a (Popt) and PPeu were fairly well and estimated values from the new algorithms almost satisfied a factor of 2 of the values measured in situ. If accurate value of aph is derived from SGLI data, global estimation of PPeu without the issues of pigments packaging, CDOM and SST are expected.