| You are in About SWA Drought Monitor
About SWA Drought Monitor
General
South Asia Drought Monitor (SADM) is an
evolving drought monitoring tool, which, in its present form
is based entirely on remote sensing data. It aims to supply
timely information on drought onset, progression and areal
extent. This near-real-time drought monitoring and reporting
system currently covers Afghanistan, Pakistan and western
parts of India. The system is based on drought-related indices
derived from high resolution remote-sensing data (MODIS).
The unique feature of the system is the use of earlier established
relationship between drought-related indices obtained from
MODIS and AVHRR data. These data types have different pixel
resolution and optical characteristics (Thenkabail et al,
2004). The results ensure the continuity of the two data sets
and should allow the reports on drought development in the
region to be made in near-real time with a spatial resolution
of 500 meters and at 8 or 16 days interval.
Current structure and functionality
Behind SADM is a comprehensive data base
of digital remote sensing data, which includes the series
of datasets (one or each date and for each index).
New images of the entire study area and
individual districts/provinces in three countries are uploaded
to SADM every 16 days.
The user can examine the drought-related
ground cover condition at three levels:
- in the entire region
- at the district/province level, and
- at the pixel level (0.5 by 0.5 km)
At all three levels, the spatial distribution
of the three vegetation characteristics (indices: NDVI, NDVI
deviation from the long-term mean and VCI) can be examined.
Regional land-use / land-cover map is also
provided.
At the district and pixel level, the time
series analysis can be carried out to trace the development
of dry or wet conditions. The user can select the time period
for display and choose the index and the graph type.
Images of any index for any date since 2002
and for any districts (or entire study area) can be downloaded.
Future plans
Remote sensing data alone may not be sufficient
for making clear predictions about drought development. Also,
the information provided by the above mentioned indices may
be distorted by natural ground factors (e.g. soils, topography)
and agricultural management practices. The use of this information
together with meteorological and agricultural data is one
of the major directions for the future development of SADM.
At present, the SADM web site is an attempt
to bring the remote sensing based, drought-related information,
via Internet, to all stakeholders in the region. It is also
planed to supply short and focused reports which support the
on-line drought analysis.
SADM is targeting government agencies, research
institutions and NGOs involved in drought mitigation and calls
for collaborative action in the region and for input (technical
and data) from responsible national agencies.
It is envisaged hat SADM will evolve into
a tool for decision support in regional drought assessment
and management and that it could provide useful supporting
information at the fine level of spatial resolution.
SADM needs to be developed and tested further
to suit the specific requirement of each individual country,
but the principles on which the system is based are generic
and can be reproduced nationally – within and outside
the study region.
|