Estimation of Net Primary Production of the Kii Peninsula Using Terra/MODIS Data

Precise estimations of zonal net primary production (NPP) are vital for understanding global carbon circulation. To estimate NPP, light use efficiency (LUE) model using normalized differential vegetation index (NDVI) has been used mainly. NDVI is obtained from red and near-infrared channels only, however, recent sensors onboard satellites always have hyper-multi-spectral channels; In order to use these data effectively, which include more details about land cover, a vegetation index based on pattern decomposition method (VIPD) has been set up to estimate NPP. The present study used 2001 Terra/MODIS (moderate resolution imaging spectroradiometer) data for the Kii Peninsula, which is mainly covered by temperate forest. To validate the proposed method, we compared the satellite data-based NPP values for the evergreen with values derived from land-survey data. The proposed method estimated the annual NPP of a temperate forest on Yoshino Mountain to be 1.52plusmn0.39 kg CO₂/m²/year, which agreed with the ground-survey result of 1.50plusmn0.75 kg CO₂/m²/year, within the algorithm error. An average zonal NPP of 1.55plusmn0.40 kg CO₂/m²/year was calculated for the whole land region from 32deg30´ to 36deg24´ N latitude, 134deg30´ to 137deg06´ E longitude with an area of 3.94 times 10⁴ km².