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Livelihood Security: Climate change, conflict and migration in - UNEP

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NESDIS-STAR – GRIDDED GLOBAL VEGETATION HEALTH DATA (VHI)<br />

The NOAA NESDIS-STAR vegetation health <strong>in</strong>dex (VHI) dataset has global coverage at 16 km resolution.<br />

It comprises 7-day composite, validated vegetation health data.<br />

Strengths of the dataset:<br />

• based on measurements of the Advanced Very High Resolution Radiometer (AVHRR) onboard the<br />

NOAA satellite → objective, up-to-date <strong>and</strong> reliable data source<br />

• dataset is cont<strong>in</strong>uous <strong>in</strong> space <strong>and</strong> time (global coverage)<br />

• time-series enables retrospective <strong>change</strong> analysis (available time-series: 1981 to date)<br />

• high temporal resolution (weekly dataset)<br />

freely available via NESDIS-STAR data portal<br />

•<br />

Weaknesses of the dataset:<br />

• dataset dates back only to 1981 (week 35)<br />

from week 36 of 1994 to week 3 of 1995 data is not available due to sensor problems<br />

•<br />

DFO – MAJOR FLOOD EVENT DATA<br />

DFO (Dartmouth Flood Observatory) major flood event data comprises a global time-series (1985-<br />

2010) of major flood events which are represented as approximated polygons. The polygons reflect<br />

the estimated areas affected by flood rather than the actual <strong>in</strong>undated areas. Accord<strong>in</strong>g to DFO, the<br />

flood-affected areas (polygons) are del<strong>in</strong>eated based on various sources, such as onl<strong>in</strong>e news reports,<br />

governmental <strong>and</strong> <strong>in</strong>ternational relief agency websites <strong>and</strong> satellite imagery.<br />

Strengths of the dataset:<br />

• global, up-to-date dataset<br />

• time-series enables retrospective <strong>change</strong> analysis (available time-series: 1985 to date)<br />

freely available at DFO website<br />

•<br />

Weaknesses of the dataset:<br />

• dataset does not reflect the actually <strong>in</strong>undated areas<br />

time-series dates back only to 1985<br />

•<br />

CSI-CGIAR – SRTM v4 GRIDDED 90 m ELEVATION DATA<br />

The SRTM 90 meter Digital Elevation Model (DEM) has a resolution of 90 m at the equator, <strong>and</strong> is provided<br />

<strong>in</strong> mosaics of 5 degree resolution tiles.<br />

Strengths of the dataset:<br />

• cont<strong>in</strong>uous <strong>in</strong> space (global coverage)<br />

• high spatial resolution (90 m)<br />

• vertical accuracy (< 9 m) is much higher than the vertical accuracy of the ASTER GDEM (+/- 20 m)<br />

• high quality coastl<strong>in</strong>e<br />

freely available at CGIAR-CSI SRTM website<br />

•<br />

Weaknesses of the dataset:<br />

• vertical accuracy (< 9 m) is not sufficient to del<strong>in</strong>eate small <strong>change</strong>s <strong>in</strong> sea level (cm)<br />

AFRICAN POPULATION DATABASE (APD) – GRIDDED AFRICAN POPULATION DATA<br />

The population figures of the <strong>UNEP</strong> African Population Database (APD) represent estimated totals for the<br />

st<strong>and</strong>ardized years 1960, 1970, 1980, 1990 <strong>and</strong> 2000 (10-year <strong>in</strong>tervals). Data sources vary by country<br />

(censuses, national statistical offices, etc.). The African Population Database provides population count<br />

<strong>and</strong> population density <strong>in</strong>formation at a spatial resolution of 2.5 arc m<strong>in</strong>utes.<br />

<strong>Livelihood</strong> <strong>Security</strong>: <strong>Climate</strong> Change, Migration <strong>and</strong> Conflict <strong>in</strong> the Sahel<br />

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