Project Research
Resume:
Geophysical Research Abstracts
EGU General Assembly 2012
Author(s) 2012
Drought monitoring over the Horn of Africa using remotely sensed
evapotranspiration, soil moisture and vegetation parameters
J. Timmermans (1), M. Gokmen (1), U. Eden (1,2), M. Abou Ali (3), Z. Vekerdy (1), and Z. Su (1)
(1) ITC, Water Resources, Enschede, Netherlands (************@***.**), (2) Ministry of Works and Human Settlement in
Bhutan, Department of Urban Development and Engineering Services (DUDES), (3) San Diego State University,
Computational Science Research Center
The need to good drought monitoring and management for the Horn of Africa has never been greater. This ongoing
drought is the largest in the past sixty years and is effecting the life of around 10 million people, according to
the United Nations. The impact of drought is most apparent in food security and health. In addition secondary
problems arise related to the drought such as large migration; more than 15000 Somalia have ed to neighboring
countries to escape the problems caused by the drought. These problems will only grow in the future to larger
areas due to increase in extreme weather patterns due to global climate change. Monitoring drought impact and
managing the drought effects are therefore of critical importance.
The impact of a drought is hard to characterize as drought depends on several parameters, like precipita-
tion, land use, irrigation. Consequently the effects of the drought vary spatially and range from short-term to
long-term. For this reason a drought event can be characterized into four categories: meteorological, agricul-
tural, hydrological and socio-economical. In terms of food production the agricultural drought, or short term
dryness near the surface layer, is most important. This drought is usually characterized by low soil moisture
content in the root zone, decreased evapotranspiration, and changes in vegetation vigor. All of these parameters
can be detected with good accuracy from space. The advantage of remote sensing in Drought monitoring is evident.
Drought monitoring is usually performed using drought indices, like the Palmer Index (PDSI), Crop Mois-
ture Index (CMI), Standard Precipitation Index (SPI). With the introduction of remote sensing several indices
of these have shown great potential for large scale application. These indices however all incorporate precipi-
tation as the main surface parameter neglecting the response of the surface to the dryness. More recently two
agricultural drought indices, the EvapoTranspiration De cit Index (ETDI) and the Soil Moisture De cit Index
(SMDI), have been proposed to investigate this. The ETDI considers the stress ratio caused by the difference
between potential and actual evapotranspiration, while SMDI considers the variation in soil moisture avail-
ability to the plant. As there is not a single unique accepted de nition of drought, investigation into the impact
of drought should not be con ned to a single drought index; instead several indices need to be used for this purpose.
The objective of this research is to investigate the drought in the Horn of Africa using several remote sens-
ing drought indices and vegetation parameters. In this research the drought will be investigated using SPI, ETDI,
SMDI, NDVI and SPI. For this purpose ETDI and SMDI will be estimated from remote sensing products for
the period from 2002 till 2011that are created in framework of the WACMOS project. The research involves the
comparison of the different drought indices and the research into possible synergies to enhance drought monitoring.
Contact this candidate