本研究應用1999-2002年共11幅SPOT衛星遙測影像,監測大肚山台地天竺草(Panicum maximum)植被亮度指數(brightness index, BRI)之季節性變化;並以灰關聯理論分析1994-2002年氣候因子包括累積降雨量、平均相對溼度、日照率、平均氣溫、與累積全天日射量,對天竺草衛星遙測BRI之相關性。結果顯示,在大肚山台地,這五種氣候因子對天竺草衛星遙測BRI貢獻度之灰序(grey order)分別為:平均氣溫>累積全天日射量>日射率>平均相對溼度>累積降雨量。此結果進一步顯示,日光相關因子(sunlight-related factors)對天竺草衛星遙測BRI之貢獻比水分相關因子(watert-related factors)都大。此與磺嘴山地區類地毯草之結果剛好相反,可能代表草類植物對不同氣候環境之適應不同或氣候因子對不同草類植物之影響不同。
Eleven sets of SPOT satellite imageries taken between 1999-2002 and are equivalent to eleven months, were used to monitor the seasonal changes in the brightness index (BRI) of guineagrass (Panicum maximum Jacq.) in Mt. Dadu area at central Taiwan. The grey system theory was applied to pinpoint the effect of five climate factors on the satellite remote sensing BRI of P. maximum. The contribution degrees of climate factors, indicated by grey order, to satellite remote sensing BRI of P. maximum are: monthly mean temperature>daily cumulative irradiance>daily insolation percentage>monthly mean relative humidity>monthly cumulative precipitation. The data further suggest that sunlight-related factors (SRFs) play more important role in satellite remote sensing BRI of P. maximum in Mt. Dadu area than water-related factors (WRFs). The present data are in contrast to carpetgrass (Axonopus affinis Chase) in Mt. Huangzui area. The difference in grey relational analysis between guineagrass and carpetgrass may be resulted from their adaptation to climate environments.