Climate Monitoring

Observations for

a) Dekadal (i.e., ~10-daily) precipitation estimates for the selected region over the past 3 years.

b) Dekadal (i.e., ~10-daily) precipitation anomalies (from 1983-2010 climatology) for the selected region over the last past 3 years.

c) Smoothed dekadal (i.e., ~10-daily) precipitation for the current year (thick black line), as indicated by the axis labels. Precipitation from previous years are also shown (blue-1 yr from present; magenta- 2 yrs from present; grey-3 yrs from present).

d) Cumulative dekadal satellite-derived precipitation (solid black line) and the cumulative long-term average precipitation (grey dotted line) for the most recent 12-month period in the selected region. The blue (red) bars are indicative of precipitation that is above (below) the long-term average.

Climate Monitoring

Precipitation

The Analysis menu allows to view different analysis of the dekad in view. The default map on this page displays dekadal (aproximately 10-day) precipitation amounts over the country. The default map shows precipitation totals for the most recently available dekad, but totals for previous dekads can be displayed as well. By clicking on a location on the map the user can generate four time series graphs that provide analyses of recent rainfall averaged over an administrative district or box of a selected size, with respect to that of recent seasons and the long-term multiple-year average.

Precipitation Anomaly

Precipitation Anomaly map displays the difference between the most recent dekadal rainfall estimates and the long term average (from 1983 to 2010). Positive (negative) values indicate dekadal estimates that are above (below) the long term average or climatology.

Standard Precipitation Index

SPI map displays the standard precipitation index of the most recent dekadal rainfall (1983 to 2010 base period). The Standardized Precipitation Index (SPI; McKee 1993) is the number of standard deviations that observed cumulative precipitation deviates from the climatological average. To compute the index, a long-term time series of precipitation accumulations over dekads are used to estimate an appropriate probability density function. The analyses shown here are based on the Pearson Type III distribution (i.e., 3-parameter gamma) as suggested by Guttman (1999). The associated cumulative probability distribution is then estimated and subsequently transformed to a normal distribution. The result is the SPI, which can be interpreted as a probability using the standard normal distrubtion (i.e., users can expect the SPI be within one standard deviation about 68% of the time, two standard deviations about 95% of the time, etc.) The analyses shown here utilize the FORTRAN code made available by Guttman (1999). Places where the dekadal climatology is less than 2 mm are masked.

 SPI Values Category
  = 2.00 Extremely Wet
  1.50 to 1.99 Severely Wet
  1.00 to 1.49 Moderately Wet
  -0.99 to 0.99 Near Normal
  -1.00 to -1.49   Moderately Dry  
    -1.50 to -1.99  Severely Dry
  = -2.00 Extremely Dry

Table adapted from McKee et al. (1993)

Dataset Documentation

Reconstructed rainfall over land areas on a 0.1 x 0.1 deg. lat/lon grid from Ethiopia National Meteorology Agency.

Helpdesk

Contact help@iri.columbia.edu with any technical questions or problems with this Map Room.