Drought

Lake Chad has shrunk dramatically over the last four decades due to a decrease in rainfall and an increase in the amount of water used for irrigation projects. Its surface area was 25 000 sq km in the early 1960s, compared with 1350 sq km in 2001. Image acquired 19 December 2007 by the MERIS (Medium Resolution Imaging Spectrometer) instrument aboard ESA’s Envisat satellite. Image: ESA, CC BY-SA 3.0 IGO.

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).

Related content on the Knowledge Portal

GP-STAR factsheet

Publishing institution: International Centre for Integrated Mountain Development (ICIMOD)

The identification of critical glacial lakes is based on remote sensing method in which several criteria related to glacial lakes, glaciers and physical condition of surrounding area is considered to assess potential for future outburst and possible glacial lake outburst flood (GLOF).

Publishing institution: UNITAR Operational Satellite Applications Programme (UNOSAT)

Based on optical and radar images of different resolutions, UNOSAT products are also enriched with the available baseline GIS datasets and crowdsourcing data. Satellite-derived analysis performed by UNOSAT is delivered in the form of GIS Data, Static Maps, Live Web Maps, and Reports, and is then shared with a wide range of end-users such as UN Agencies, International Organizations, and Governments.

The Global Human Settlement (GHS) framework produces global open source spatial information about the human presence on the planet over time. This is in the form of built up maps, population density maps and settlement maps. This information is generated with evidence-based analytics and knowledge using new spatial data mining technologies. The framework uses heterogeneous data including global archives of fine-scale satellite imagery, census data, and volunteered geographic information. The data is processed fully automatically and generates analytics and knowledge reporting objectively and systematically about the presence of population and built-up infrastructures. 

Publishing institution: International Working Group on Satellite Emergency Mapping (IWG‐SEM)

The guidelines will be reviewed and updated periodically, in order to integrate new best practices and to be responsive to evolutions in technology and end-user needs. The IWG-SEM chair has the responsibility to initiate the review, by agreement of the Working Group. 

The production and the maintenance of the guidelines are based on a joint effort by the members of the International Working Group on Satellite-based Emergency Mapping (IWG- SEM), a voluntary group of organizations involved in satellite-based emergency mapping. It was founded to improve cooperation, communication and professional standards among the global network of satellite-based emergency mapping providers. The chairperson of the group is nominated for a term of one year and is responsible for organizing the monthly telecons and bi-annual meetings. The current chair is from the Department of Geoinformatics, Z_GIS University of Salzburg / Spatial Services Ltd, Austria.

Publishing institution: International Water Management Institute (IWMI)

IDSI integrates multi-source remote sensing data from moderate resolution imaging spectroradiometer (MODIS) and tropical rainfall measuring mission (TRMM), ESA Soil Moisture (ASCAT) Products and it synthesizes precipitation deficits, soil thermal stress and vegetation growth status in drought process. Therefore, this method is favourable to monitor the comprehensive drought over South Asia.

Publishing institution: United Nations Economic and Social Commission for Asia and the Pacific

Intensive capacity development sessions for Pacific island countries  (Cook Islands, Fiji, Kiribati, Micronesia (the Federated States of), Samoa, Solomon Islands, Tonga, and Vanuatu).

The project aims to enhance institutional and technical capacity for using geospatial data and technology applications and promote regional cooperation for sharing geospatial data for disaster management in Pacific island countries.

Publishing institution: United Nations Economic and Social Commission for Asia and the Pacific

Persistent and prolonged droughts in Cambodia are severely affecting agricultural production, specifically for rice. Cambodia is moving towards improving drought management through ESCAP’s Regional Drought Mechanism. Supported by China, a tailored drought monitoring system is being established through DroughtWatch at different scales using different earth observation data. The Government of Australia is working towards building a water accounting system for Cambodia, using its innovative tool Source. In addition, Australia, with support from Thailand, is also working towards supporting both of these tools by establishing a pilot DataCube for Cambodia to improve storage of pre-processed Earth observation data. Working with institutes such as the Regional Integrated Multi-Hazard Early Warning System for Africa and Asia (RIMES), information can be shared before the start of the growing season through their Monsoon Forums.  Additional partners, such as UNOSAT, are supporting capacity... read more

Publishing institution: United Nations Economic and Social Commission for Asia and the Pacific

Developed for the needs of the ASEAN sub-region in Asia and the Pacific, the handbooks can also be adapted for use in other regions.

The handbooks have been developed through expert working groups, in collaboration with United Nations partners including UNOOSA/UN-SPIDER, UNITAR-UNOSAT, and OCHA. As well as extensive consultation with space agencies, national disaster management authorities and regional institutions, including GISTDA, LAPAN, ASEAN Coordinating Centre for Humanitarian Assistance on Disaster Management and Asian Institute of Technology.

 

 

Publishing institution: United Nations Office for Outer Space Affairs (UNOOSA)

Vegetation Condition Index according to Kogan et al. (1990). Two-weeks normalized Differenced Vegetation Index (NDVI) composites based on 250m MODIS data are freely available for download from the MODIS/NDVI Time Series Database from the Global Agriculture Monitoring (GLAM) Project provided via the website of Geographic Department of Maryland University.

Pages

Hazard group

Terms in the same hazard group

Zircon - This is a contributing Drupal Theme
Design by WeebPal.