Interannual memory effects for spring NDVI in semi-arid South Africa

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dc.contributor.authorRichard, Yves
dc.contributor.authorMartiny, Nadège
dc.contributor.authorFauchereau, Nicolas
dc.contributor.authorReason, Chris
dc.contributor.authorRouault, Mathieu
dc.contributor.authorVigaud, Nicolas
dc.contributor.authorTracol, Yann
dc.date.accessioned2021-10-08T07:04:07Z
dc.date.available2021-10-08T07:04:07Z
dc.date.issued2008
dc.description.abstractAlmost 20 years of Normalized Difference Vegetative Index (NDVI) and precipitation (PPT) data are analysed to better understand the interannual memory effects on vegetation dynamics observed at regional scales in Southern Africa (SA). The study focuses on a semi-arid region (25°S–31°S; 21°E–26°E) during the austral early summer (September–December). The memory effects are examined using simple statistical approaches (linear correlations and regressions) which require the definition of an early summer vegetation predictand (December NDVI minus September NDVI) and a consistent set of potential predictors (rainfall amount, number of rainy days, rainfall intensity, NDVI and Rain-Use-Efficiency) considered with 4 to 15-month time-lag. An analysis over six SA sub-regions, corresponding to the six major land-cover types of the area reveals two distinct memory effects. A “negative” memory effect (with both rainfall and vegetation) is detected at 7 to 10-month time-lag while a “positive” memory effect (with vegetation only) is observed at 12 to 14-month time-lag. These results suggest that interannual memory effects in early summer vegetation dynamics of semi-arid South Africa may preferably be driven by biological rather than hydrological mechanisms.
dc.identifier.apacitationRichard, Y., Martiny, N., Fauchereau, N., Reason, C., Rouault, M., Vigaud, N., & Tracol, Y. (2008). Interannual memory effects for spring NDVI in semi-arid South Africa. <i>Geophysical Research Letters</i>, 35(13), 174 - 177. http://hdl.handle.net/11427/34431en_ZA
dc.identifier.chicagocitationRichard, Yves, Nadège Martiny, Nicolas Fauchereau, Chris Reason, Mathieu Rouault, Nicolas Vigaud, and Yann Tracol "Interannual memory effects for spring NDVI in semi-arid South Africa." <i>Geophysical Research Letters</i> 35, 13. (2008): 174 - 177. http://hdl.handle.net/11427/34431en_ZA
dc.identifier.citationRichard, Y., Martiny, N., Fauchereau, N., Reason, C., Rouault, M., Vigaud, N. & Tracol, Y. 2008. Interannual memory effects for spring NDVI in semi-arid South Africa. <i>Geophysical Research Letters.</i> 35(13):174 - 177. http://hdl.handle.net/11427/34431en_ZA
dc.identifier.issn0094-8276
dc.identifier.issn1944-8007
dc.identifier.ris TY - Journal Article AU - Richard, Yves AU - Martiny, Nadège AU - Fauchereau, Nicolas AU - Reason, Chris AU - Rouault, Mathieu AU - Vigaud, Nicolas AU - Tracol, Yann AB - Almost 20 years of Normalized Difference Vegetative Index (NDVI) and precipitation (PPT) data are analysed to better understand the interannual memory effects on vegetation dynamics observed at regional scales in Southern Africa (SA). The study focuses on a semi-arid region (25°S–31°S; 21°E–26°E) during the austral early summer (September–December). The memory effects are examined using simple statistical approaches (linear correlations and regressions) which require the definition of an early summer vegetation predictand (December NDVI minus September NDVI) and a consistent set of potential predictors (rainfall amount, number of rainy days, rainfall intensity, NDVI and Rain-Use-Efficiency) considered with 4 to 15-month time-lag. An analysis over six SA sub-regions, corresponding to the six major land-cover types of the area reveals two distinct memory effects. A “negative” memory effect (with both rainfall and vegetation) is detected at 7 to 10-month time-lag while a “positive” memory effect (with vegetation only) is observed at 12 to 14-month time-lag. These results suggest that interannual memory effects in early summer vegetation dynamics of semi-arid South Africa may preferably be driven by biological rather than hydrological mechanisms. DA - 2008 DB - OpenUCT DP - University of Cape Town IS - 13 J1 - Geophysical Research Letters LK - https://open.uct.ac.za PY - 2008 SM - 0094-8276 SM - 1944-8007 T1 - Interannual memory effects for spring NDVI in semi-arid South Africa TI - Interannual memory effects for spring NDVI in semi-arid South Africa UR - http://hdl.handle.net/11427/34431 ER - en_ZA
dc.identifier.urihttp://hdl.handle.net/11427/34431
dc.identifier.vancouvercitationRichard Y, Martiny N, Fauchereau N, Reason C, Rouault M, Vigaud N, et al. Interannual memory effects for spring NDVI in semi-arid South Africa. Geophysical Research Letters. 2008;35(13):174 - 177. http://hdl.handle.net/11427/34431.en_ZA
dc.language.isoeng
dc.publisher.departmentDepartment of Oceanography
dc.publisher.facultyFaculty of Science
dc.sourceGeophysical Research Letters
dc.source.journalissue13
dc.source.journalvolume35
dc.source.pagination174 - 177
dc.source.urihttps://dx.doi.org/10.1029/2008GL034119
dc.subject.otherland cover
dc.subject.otherefficiency
dc.subject.otherintensity
dc.subject.otherrainfall
dc.subject.otherPredictor
dc.subject.othervegetation
dc.subject.otherregression
dc.subject.othercorrelation
dc.subject.otherSummer
dc.subject.otherSemi arid zone
dc.subject.otherRegional scope
dc.subject.otherVegetation dynamics
dc.subject.otheratmospheric precipitation
dc.subject.otherSpring(season)
dc.subject.othersprings
dc.subject.otherSouthern Africa
dc.subject.otherSouth Africa
dc.subject.otherAfrica
dc.subject.otherOccupation sol
dc.subject.otherEfficacité
dc.subject.otherIntensité
dc.subject.otherPluie
dc.subject.otherPrédicteur
dc.subject.otherVégétation
dc.subject.otherRégression
dc.subject.otherCorrélation
dc.subject.otherEté
dc.titleInterannual memory effects for spring NDVI in semi-arid South Africa
dc.typeJournal Article
uct.type.publicationResearch
uct.type.resourceJournal Article
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