Wessels, Konrad JBachoo, AKArchibald, S2011-09-232011-09-232009-05Wessels, KJ, Bachoo, AK and Archibald, S. 2009. Influence of composite period and date of observation on phenological metrics extracted from MODIS data. 33rd International Symposium on Remote Sensing of Environment: Sustaining the Millennium Development Goals, Stresa, Lago Magglore, Italy, 4-8 May 2009http://hdl.handle.net/10204/517433rd International Symposium on Remote Sensing of Environment: Sustaining the Millennium Development Goals, Stresa, Lago Magglore, Italy, 4-8 May 2009Deriving date-specific phenometrics from different multi-day MODIS composite data can potentially yield very different results. The objectives of this study were therefore to quantify the differences between (i) using 8-day vs. 16-day MODIS data and (ii) using the date-flag in the 8-day MOD09 data when estimating key phenological metrics for Skukuza, South Africa. After applying Savitsky-Golay filtering, date specific phenometrics were extracted using the threshold (10% of amplitude) and delayed moving average (DMA) methods respectively. The phenometric dates calculated using the 8-day vs. 16-day composite data differed by up to 30 days, as in the case of onset of greenness decrease. Consistent differences were also found between the results of the DMA and threshold methods as they potentially identify different phonological events. The phenometrics extracted are therefore highly influenced by the MODIS input data and methods used and thus trends in such phenometrics should be interpreted with caution.enPhenological metricsMODIS dataRemote SensingEnvironmentConference PresentationWessels, K. J., Bachoo, A., & Archibald, S. (2009). Influence of composite period and date of observation on phenological metrics extracted from MODIS data. http://hdl.handle.net/10204/5174Wessels, Konrad J, AK Bachoo, and S Archibald. "Influence of composite period and date of observation on phenological metrics extracted from MODIS data." (2009): http://hdl.handle.net/10204/5174Wessels KJ, Bachoo A, Archibald S, Influence of composite period and date of observation on phenological metrics extracted from MODIS data; 2009. http://hdl.handle.net/10204/5174 .TY - Conference Presentation AU - Wessels, Konrad J AU - Bachoo, AK AU - Archibald, S AB - Deriving date-specific phenometrics from different multi-day MODIS composite data can potentially yield very different results. The objectives of this study were therefore to quantify the differences between (i) using 8-day vs. 16-day MODIS data and (ii) using the date-flag in the 8-day MOD09 data when estimating key phenological metrics for Skukuza, South Africa. After applying Savitsky-Golay filtering, date specific phenometrics were extracted using the threshold (10% of amplitude) and delayed moving average (DMA) methods respectively. The phenometric dates calculated using the 8-day vs. 16-day composite data differed by up to 30 days, as in the case of onset of greenness decrease. Consistent differences were also found between the results of the DMA and threshold methods as they potentially identify different phonological events. The phenometrics extracted are therefore highly influenced by the MODIS input data and methods used and thus trends in such phenometrics should be interpreted with caution. DA - 2009-05 DB - ResearchSpace DP - CSIR KW - Phenological metrics KW - MODIS data KW - Remote Sensing KW - Environment LK - https://researchspace.csir.co.za PY - 2009 T1 - Influence of composite period and date of observation on phenological metrics extracted from MODIS data TI - Influence of composite period and date of observation on phenological metrics extracted from MODIS data UR - http://hdl.handle.net/10204/5174 ER -