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).
Further information
Related content
Data Source
News
Timely and reliable information about precipitation, soil moisture and vegetation health provide essential insights for early detection of drought. Space-based information, which helps monitor these parameters, is a central data source for effective drought early warning systems.
Upon the request of the Government of Ethiopia, UN-SPIDER is carrying out a Technical Advisory Mission (TAM) to Addis Ababa from 26 to 30 August to support the country in making use of the benefits of space technology for drought early warning. The team of experts from UN-SPIDER and the Centre for Remote Sensing of Land Surfaces (... read more
Advisory Support
Event
This short tutorial is the first video (Part 1) of the “Getting Started with MODIS Version 6 -Vegetation Indices Data” video series.
This video focuses on the National Aeronautics and Space Administration’s (NASA) Terra and Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) Version 6 Vegetation Indices data distributed by NASA’s Land Processes Distributed Active Archive Center (LP DAAC).
In this short tutorial, we will cover the MODIS Version 6 Vegetation Indices data products, improvements in Version 6 products over Version 5 products, and how to search for and download these data using the NASA Earthdata Search Client data access tool To learn more about MODIS Version 6 Vegetation Indices data and other data products distributed by the LP DAAC please visit... read more
This short tutorial video focuses on the National Aeronautics and Space Administration’s (NASA) Terra and Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) Version 6 Vegetation Indices data distributed by NASA’s Land Processes Distributed Active Archive Center (LP DAAC).
In this video, we'll provide you information about the MODIS Version 6 Vegetation Indices data products, discuss the scale factor of the data and other data values, and show you how to use a color map to visualize the Normalized Difference Vegetation Index (NDVI). In addition, the tutorial will also cover how to find Vegetation Indices resources on the LP DAAC website.
To learn more about NASA MODIS Version 6... read more
This video focuses on the National Aeronautics and Space Administration’s (NASA) Terra and Aqua Moderate Resolution Imaging Spectroradiometer (MODIS) Version 6 Vegetation Indices data distributed by NASA’s Land Processes Distributed Active Archive Center (LP DAAC).
This short tutorial is the 3rd video in the series and will provide the viewer with information about MODIS Vegetation Indices quality information, including how to decode quality bits, tools for working with quality data, and where to find additional information.
To learn more about MODIS Version 6 Vegetation Indices data and other data products distributed by the LP DAAC visit... read more
Sentinel-2 is the high-resolution optical satellite of ESA and the EU. The images have a resolution of 10 to 20 meters, higher than Landsat, and, as always with the Copernicus programme, the data are free and open.
In this tutorial, we’ll download an image, make it look good, and create maps of vegetation indices to show the general health of crops and other vegetation. This is a basic tutorial, but even for those with experience in remote sensing, it is a good starting point for working with Sentinel-2 data.
Prolonged drought can result in economic, environmental, and health-related impacts. In this webinar, participants will learn how to monitor drought conditions and assess impacts on the ecosystem using precipitation, soil moisture, and vegetation data. The training will provide an overview of drought classification, as well as an introduction to web-based tools for drought monitoring and visualization. Lectures will be followed by hands-on demonstrations of data access and visualization.
Learning Objectives:
By the end of the training, participants will be able to:
