Dataset Edition

Présentation générale
Nom du jeu de donnéesTrends of vegetation in Benin (1982 - 2003) (IMPETUS dataset ID = 632)
Créé le2007-11-09
Projet(s)IMPETUS
Date de début (yyyy-mm-dd)1982-01-01Date de fin (yyyy-mm-dd)2003-12-31
Contact(s)
Accès aux données Dataset as provided by the Principal Investigator
Description du jeu de données
RésuméFor the determination of statistically significant vegetation trends indication early forms of land degradation in Benin the approach illustrated e.g. in Houn-toundji et al. (2006) has been applied. The approach is based on a strong relation be-tween vegetation dynamics and rainfall choosing rain use efficiency (RUE) as indicator for land degradation. The normalised difference vegetation index (NDVI) from NOAA Global Inventory Monitoring and Modelling Studies (GIMMS) was used for analysing vegetation cover and productivity between 1982 and 2003. The spatial resolution of the data is 8km x 8km. The precipitation data used was ob-tained by downscaling results of the atmos-pheric model REMO (see Paeth et al., Changes in Benin's monsoon climate, this Atlas). Yearly sums were calculated for NDVI (iNDVI) and rainfall (yrain) respectively. Then, for each site the rain use efficiency was calculated and trends from 1982 until 2003 examined. Therefore, the yearly ratio of iNDVI to yrain was used. Trends were determined by linear regression of the ratio (dependent variable) and time (independent variable). The regression slope was mapped in seven classes indicating different statistically significant trends based on the Student's t-test (Cf. Ek-lundh and Olsson 2003, Hountondji et al. 2006). Trends for the iNDVI to yrain ratio were labelled as strong (positive or negative) if the T-value of the slope exceeded the 0.025 p-value of either tail of the distribution. Sites were classified as medium or weak if the T-value was between the 0.025 and 0.05 p-value and be-tween 0.05 and 0.15 respectively. All other sites were classified as no trend showing no statistically significant development for this time period. The data contains the t-values! Parameter, Attribute list: correlation coefficients of rainfall and iNDVI. Dataset created by IMPETUS subproject A3.

Data Lineage: NOAA, GIMMS, REMO; No information about Data Consistency; No information about Data Completeness; No information about Positional Accuracy; No information about Quantitative Attribute Accuracy
Strategie d'observationto determine statistically significant vegetation trends in Benin
Type d'instrument
Paramètres mesurés
Paramètre mesuré 1
Nom du paramètreland use
Mot-clé du paramètreLand Surface > Land Use/Land Cover
Unité
Date de début (yyyy-mm-dd)Date de fin (yyyy-mm-dd)
Précision du capteur / Incertitude
Paramètre mesuré 2
Nom du paramètreland degradation
Mot-clé du paramètreLand Surface > Land Use/Land Cover
Unité
Date de début (yyyy-mm-dd)Date de fin (yyyy-mm-dd)
Précision du capteur / Incertitude
Paramètre mesuré 3
Nom du paramètrevegetation
Mot-clé du paramètreBiosphere > Vegetation
Unité
Date de début (yyyy-mm-dd)Date de fin (yyyy-mm-dd)
Précision du capteur / Incertitude
Paramètre mesuré 4
Nom du paramètrevegetation dynamics
Mot-clé du paramètreBiosphere > Vegetation
Unité
Date de début (yyyy-mm-dd)Date de fin (yyyy-mm-dd)
Précision du capteur / Incertitude
Paramètre mesuré 5
Nom du paramètreNDVI
Mot-clé du paramètre
Unité
Date de début (yyyy-mm-dd)Date de fin (yyyy-mm-dd)
Précision du capteur / Incertitude
Information sur l'utilisation des données
Conditions d'utilisation des donnéesPlease inform the Point of Contact if you use the data for publication
Charte d'accès aux donnéesIMPETUS data policy
Base de donnéesIMPETUS
Format des fichiers de donnéesTagged Image Format, ENVI Standard File