droughts in peru - The World AgroMeteorological Information Service

19 Pages·2010·2.37 MB·English

NATIONAL METEOROLOGY AND HYDROLOGY
SERVICE
DDRROOUUGGHHTTSS IINN PPEERRUU
Ing. Constantino Alarcón
December 2009
Since Peru is a double-nature country,
mountanious and tropical, it is
characterized by the presence of
multiple micro climates, that are altered
by the occurrence of extreme
hydrometeorological events such as
heat waves, frosts, cold fronts, heavy
rainfall, droughts, floods, causing
innumerable loss.
The presence of the Andes Mountains,
together with other climate and
oceanographic factors determine the
existence of three natural regions:
•The coast that shows desert, arid and
semi-arid characteristics.
•The mountain region, that shows a
hilly relief with deep and narrow valleys.
•The jungle which is mostly covered by
tropical forest..
A typical phenomenon of the
interannual climate variability in
Peru is the occurrence of
droughts, that every certain
periods of time occur, mainly
affecting the mountain region.

AGROMETEOROLOGICAL DROUGHT
The General Directorate of Agrometeorology carries out the
agrometeorological monitoring of the hydrographic basins at national
level, it is made using agrometeorological indices and parameters,
based on meteorological and phenological records. One of the main
activities of this monitoring is to determine rainfall deficit and droughts
for 10-day and monthly periods.
The indices used for this monitoring are:
• Humidity index (HI)
• Standardized precipitation index (SPI)
• Palmer drought severity index (PDSI)
Precipitation index (Pi)
It shows the deficit and/or excess of humidity of the crops in the
environment, place and considered period of time. The Pi is equal to the
relation between precipitation and potential evapotranspiration.
Pi=Pre/PET
Classification of Precipitation Index (Pi) adapted to rainfall regimen and soil in Peru
(SENAMHI- DGA-2002).
DECADAL VARIATION OF HUMIDITY INDEX IN THE MOUNTAIN REGION
AGRICULTURAL CAMPAIGN 2009 – 2010
Decadal variation of
the humidity index
Hi = p/ETo
SPI Ramis river basin
Agricultural campaign 2009-2010
Monthly Behavior of the SPI in the Ramis river basin
Agricultural campaign 2008-2009 Agricultural campaing 2009-2010