Remote Sensing Assessment of the Nile Basin Vegetation Cover Dynamic

Kamel Didan, The University of Arizona, didan@email.arizona.edu (Presenter)
Armando Barreto, The University of Arizona, abarreto@email.arizona.edu
Muluneh Yitayew, The University of Arizona, myitayew@email.arizona.edu

Sensitivity of the Nile’s basin vegetation cover to climate was assessed using a simple diagnostic and correlation analysis approach. Over the last 30 years the basin experienced extreme climate events, in particular droughts (80’ies) and a noticeable and sustained recovery starting in the 90ies. We looked at the associated changes in the vegetation index signal over the same period using the V4 VIP (vip.arizona.edu) seamless multi-sensor long-term data record of vegetation index and phenology compiled from AVHRR and MODIS sensors. Additionally climate data for the corresponding 30-year period was acquired from the Global Precipitation Climatology Centre (GPCC) and temperature from the Global Historical Climatology Network-Monthly (GHCN-M). A single year (2002) MODIS based Land Cover data was also used to cluster and assess change based on the vegetation types.

The global correlation between VI and climate drivers anomalies was very complex, with T and P switching roles. The VI correlation with P and T was significant in the late 80’ies (drier and hotter). In the early 90’ies precipitation recovered leading to a decoupling of the vegetation response and weakening of the correlation. Starting late 90’ies a divergence develops, where VI anomalies remained positively and strongly correlated with P, while the correlation with T anomalies became insignificant. As T continues to rise and P continues to recover the VI anomalies correlation switched direction, where P impact became insignificant while T started to correlate positively with the VI anomaly. Temperature started to play the more prominent role in the Land cover dynamic and change.

These diagnostic results coupled with climate models projection point to major negative impacts on the basin’s vegetation cover, productivity, and eventually their associated ecosystem services. These results suggest that the earlier changes will be experienced by the higher elevation areas.

Presentation Type:  Poster

Session:  General Contributions   (Tue 4:35 PM)

Associated Project(s): 

• Didan, Kamel: Terra and Aqua MODIS Vegetation Index Product Suite: Where to go From Here? Transition Toward Core Production and Readiness for VIIRS era ...details

Poster Location ID: 140