Precipitation Estimate Differences

This map shows dekadal (10-day) precipitation estimates as the difference from the short term average (from 2000 to last recent complete year).

Positive (negative) values indicate dekadal estimates that are above (below) the short-term average Precipitation.

Precipitation, especially in warm semi-arid and desert fringe areas, is one of the factors responsible for creating the conditions which lead to the formation of sufficient surface water and moisture for mosquito breeding sites.

The Precipitation Estimate Differences values are different from conventional precipitation anomalies because they are based on a short-term average and not the typical long-term (e.g., 30-year) average. This comparison provides insight into changes in malaria risk relative to a recent historical perspective.

Alternatively, precipitation estimates can also be expressed as percentages of the short-term average, This data can be viewed on the (Precipitation Estimate Percentages) map page.

References:

WHO: Final report on the 3rd meeting of the RBM Technical Resource Network on Epidemic Prevention and Control. Geneva: World Health Organization; 2002.

Dataset Documentation

RED maps are produced every 10 days on an 11 km spatial resolution basis. Dekadal estimates and short-term averages are derived from the Climate Prediction Center/Famine Early Warning System. Areas where the average accumulation for the selected dekad is less than 7 mm are not shown in the analysis.

Precipitation Estimates

Data
Dekadal precipitation on a 0.1 x 0.1 deg. lat/lon grid
Data Source
Climate Prediction Center/Famine Early Warning System (CPC/FEWS RFE2.0)*

Precipitation Estimate Short-Term Average

Data
Dekadal precipitation on a 0.1 x 0.1 deg. lat/lon grid
Base Period: 1 Jan 2000 to 31 Dec of last year
Data Source
Climate Prediction Center/Famine Early Warning System (CPC/FEWS RFE2.0)*

Epidemiological Mask

This map utilizes an epidemiological mask to isolate areas prone to new exposure of malaria. The mask allows for RED to be exclusively illustrated in areas where malaria is considered to be epidemic, therefore, areas where malaria transmission is considered absent or endemic are excluded. The mask is based purely on climatic constraints to malaria transmission and does not yet account for areas in the northern and southern margins of the continent where control has eliminated malaria risk.
Reference
WHO: Final report on the 3rd meeting of the RBM Technical Resource Network on Epidemic Prevention and Control. Geneva: World Health Organization; 2002.

*More dekadal and daily data from FEWS is available from the Africa Data Dissemination Service.

Dataset

Access the dataset used to create this map.

Helpdesks

Contact help@iri.columbia.edu with any technical questions or problems with this Map Room, for example, the forecasts not displaying or updating properly.

Instructions

The default map on this page displays the most recent dekadal (10-day) precipitaion estimates over Africa as percentages of the short-term average. As the user moves the cursor over the map, a tool bar will appear on top that will allow for previous dekads (1999-to the most recent dekad) to be displayed.

The interface consists of a clickable map that allows users to generate customized time series graphs. When a desired location is clicked, four time series graphs are generated that provide analyses of recent precipitation with respect to that of recent seasons and the short-term multiple-year average.

By placing recent precipitation in historical context, comparisons can be made to past outbreaks and useful early warning information can be developed for epidemic prone regions.