Drought

Definition

Drought may be considered in general terms a consequence of a reduction over an extended period of time in the amount of precipitation that is received, usually over a season or more in length. It is a temporary aberration, unlike aridity, which is a permanent feature of the climate. Seasonal aridity (i.e., a well-defined dry season) also needs to be distinguished from drought. It should be noted that drought is a normal, recurrent feature of climate, and it occurs in virtually all climatic regimes (UNDDR).

Facts and figures

Droughts are often predictable: periods of unusual dryness are normal in all weather systems. Advance warning is possible (WHO).

By 2025, 1.8 billion people will experience absolute water scarcity, and 2/3 of the world will be living under water stressed conditions (UNCCD).

Drought can be defined according to meteorological, agricultural, hydrological and socio-economic criteria.

  • Meteorological, when precipitation departs from the long-term normal
  • Agricultural, when there is insufficient soil moisture to meet the needs of a particular crop at a particular time. Agricultural drought is typically evident after meteorological drought but before a hydrological drought
  • Hydrological, when deficiencies occur in surface and subsurface water supplies
  • Socio-economic, when human activities are affected by reduced precipitation and related water availability. This form of drought associates human activities with elements of meteorological, agricultural, and hydrological drought (FAO).

UN-SPIDER Regional Support Offices with hazard-specific expertise

Related content on the Knowledge Portal

  • The Deimos-1 mission is fully owned and operated by Deimos Imaging (DMI), an UrtheCast company. Deimos-1 satellite was successfully launched on 29 July 2009 from the Baikonur Launch Complex (Kazakhstan) in the Russian-Ukrainian Dnepr launcher. The mission is fully dedicated to Earth Observation and captures images all around the world. Thus, currently the Deimos-1 system provides capabilities well above and beyond the design goals.
    The payload is a three-band multispectral imager system with 22m Ground Sample Distance (GSD) at nominal altitude (663 km) with 625 km swath, 8 or 10 bits radiometric depth available. Imager delivers data in three spectral bands, very close to the Near-Infrared (NIR), Red (R) and Green (G) bands in the Landsat series of US satellites. The satellite payload is a dual bank linear CCD push broom imager, so that banks are mounted at an angle to provide a wide imaging swath, one of the most characteristics Deimos-1 features.

    Instrument:…

    read more
    29/07/2009
  • UK-DMC2 is based on the SSTL-100 satellite platform and was launched in 2009 for the commercial imaging company, DMCii (a subsidiary of SSTL). It provides high resolution (22m) imagery from a sun-synchronous orbit over very large areas (650km swath, 2000km along track), with a daily revisit to global targets.
    The UK-DMC2 satellite carries a multispectral optical instrument with a spatial resolution of 22 m with three spectral bands (red, green, NIR) and a wide swath of more than 600 km. UK-DMC2 operates within the Disaster Monitoring Constellation, the first Earth observation constellation of low cost small satellites providing daily images for applications including global disaster monitoring. The Disaster Monitoring Constellation is coordinated by DMC International Imaging Ltd (DMCii) for disaster response within the International Charter: Space & Major Disasters.

    Instrument: SLIM6-22
    - compact imager with 22m GSD at 686km orbital height…

    read more
    29/07/2009
  • NOAA-19, designated NOAA-N' (NOAA-N Prime) prior to launch, is the last of the United States National Oceanic and Atmospheric Administration's POES series of weather satellites. NOAA-19 was launched on February 6, 2009.

    On November 4, 2008, NASA announced that the satellite had arrived at Vandenberg aboard a C-5 Galaxy military transport aircraft. Installation of the payload fairing took place January 27, 2009; second stage propellant was loaded on January 31.

    Several attempts were made to conduct the launch. The first attempt was scrubbed after a failure was detected in a launch pad gaseous nitrogen pressurization system. The second attempt was scrubbed after the failure of a payload fairing air conditioning compressor, which is also part of the ground support equipment at the launch pad.

    The satellite was successfully launched at about 2:22 a.m. PST. February 6, 2009 aboard a Delta II flying in the…

    read more
    06/02/2009
  • The GeoEye-1 satellite sensor was successfully launched on September 6, 2008. The satellite, which was launched at Vanderberg Air Force Base, California, provides a resolution of 0.46 meters.

    GeoEye-1 is capable of acquiring image data at 0.46 meter panchromatic (B&W) and 1.84 meter multispectral resolution. It also features a revisit time of less than three days, as well as the ability to locate an object within just three meters of its physical location.
    The GeoEye-1 satellite sensor features the most sophisticated technology ever used in a commercial remote sensing system. This sensor is optimized for large projects, as it can produce over 350,000 square kilometers of pan-sharpened multispectral satellite imagery every day.
    GeoEye-1 has been flying at an altitude of about 681 kilometers and is capable of producing imagery with a ground sampling distance of 46 centimeters, meaning it can detect objects of that diameter or greater.
    During late summer of…

    read more
    06/09/2008
  • RapidEye is a full end-to-end commercial Earth Observation system comprising a constellation of five minisatellites, a dedicated SCC (Spacecraft Control Center), a data downlink ground station service, and a full ground segment designed to plan, acquire and process up to 5 million km2 of imagery every day to generate unique land information products.
    The system is owned and operated by BlackBridge. MDA (MacDonald, Dettwiler and Associates Ltd) was the mission prime contractor and was responsible for the delivery of the space and ground segments, launch of the constellation, and on-orbit commissioning and camera calibration. The two major subcontractors to MDA were SSTL (Surrey Satellite Technology Ltd.) for the spacecraft bus, SCC and spacecraft AIT (Assembly, Integration and Test) services, as well as Jena Optronik GmbH (JOP) who provided the 5-band multispectral imager (RGB, red edge, and near IR bands).
    The RapidEye constellation represents a major milestone…

    read more
    29/08/2008
  • Cartosat-2 is an advanced remote sensing satellite with a single panchromatic camera (PAN) capable of providing scene-specific spot imageries for cartographic applications. The camera is designed to provide imageries with better than one meter spatial resolution and a swath of 10 km. The satellite will have high agility with capability to steer along and across the track up to + 45 degrees. It will be placed in a sun-synchronous polar orbit at an altitude of 630 km. It will have a revisit period of four days. The re-visit can be improved to one day with suitable orbit manoeuvres.

    Several new technologies like two mirror on axis single camera, Carbon Fabric Reinforced Plastic based electro optic structure, lightweight, large size mirrors, JPEG like data compression, advanced solid state recorder, high-torque reaction wheels and high performance star sensors are being employed in Cartosat-2.

    Instrument: PAN (Panchromatic…

    read more
    28/04/2008
  • The WorldView-1 offers a high-capacity, panchromatic imaging system which features 0.46m resolution imagery.

    Operating at an altitude of 496 kilometers, WorldView-1 satellite has an average revisit time of 1.7 days and is capable of collecting up to 750,000 square kilometers (290,000 square miles) per day of half-meter imagery. The satellite is also equipped with state-of-the-art geo-location capabilities and exhibits stunning agility with rapid targeting and efficient in-track stereo collection.

    WorldView-1 satellite sensor was successfully launched from Vandenberg Air Force Base, California, U.S.A., at 11:35 Hrs Pacific Daylight Time (PDT) on September 18th, 2007.

    Instrument: WV60 (WorldView-60 camera)
    - spectral range 0.45 - 0.90 µm
    - swath width: 17.6km at nadir
    - pushbroom imager

    18/09/2007
  • TerraSAR-X is a German Earth-observation satellite. Its primary payload is an X-band radar sensor with a range of different modes of operation, allowing it to record images with different swath widths, resolutions and polarisations. TerraSAR-X thus offers space-based observation capabilities that were previously unavailable. The objective of the mission is to provide value-added SAR (Synthetic Aperture Radar) data in the X-band, for research and development purposes as well as scientific and commercial applications.
    The successful launch of TerraSAR-X on 15 June 2007 at 08:14 local time from the Russian Baikonur Cosmodrome in Kazakhstan marked the start of a campaign to map the Earth at an unprecedented level of accuracy. The aim is to create new, high-quality radar images of the Earth’s surface.

    Instrument: SAR (Synthetic Aperture Radar)
    - the sensor operates in the X-band and in 3 different modes (Spotlight, Stripmap, ScanSAR)

    15/06/2007
  • METOP (Meteorological Operational) is Europe's first polar-orbiting operational meteorological satellite. It is the European contribution to the Initial Joint Polar System (IJPS), a co-operative agreement between Eumetsat and the US National Oceanic and Atmospheric Administration (NOAA) to provide data for climate and environmental monitoring and improved weather forecasting. The first MetOp-A satellite was launched in 2006, with the other two following at five-year intervals. In total, the programmes will be operational for at least 14 years.
    Launched in October 2006, MetOp-A, the first satellite in the series of three, replaced one of two satellite services operated by NOAA and is Europe’s first polar-orbiting satellite dedicated to operational meteorology. Once operational in orbit, responsibilities for the meteorological satellite services have been shared between the USA and Europe.
    The MetOp satellites are designed to work in conjunction with the NOAA satellite…

    read more
    19/10/2006
  • KOMPSAT-2 (Korea Multi-Purpose Satellite-2), also referred to as Arirang-2 by South Korea, has been developed by KARI (Korea Aerospace Research Institute) to continue the observation program of the KOMPSAT-1 mission.

    The main mission objectives of the KOMPSAT-2 system are to provide a surveillance of large scale disasters and its countermeasure, acquisition of independent high resolution images for GIS (Geographic Information Systems), composition of printed maps and digitized maps for domestic and overseas territories, balanced development of Korean territories, survey of natural resources, and continuation of satellite earth observation after KOMPSAT-1.

    Instrument: MSC (Multispectral Camera)
    - resolution: 1m panchromatic, 4m multispectral
    - swath width: approx. 15km

     

    28/07/2006

Term Parents

UN-SPIDER Regional Support Offices with hazard-specific expertise