Temperature extrema

Definition

A general term for temperature variations above (extreme heat) or below (extreme cold) normal conditions (IRDR Glossary).

Since climate varies regionally, the definition of an extreme temperature and its threshold will differ from location to location. In other words, an extreme value in one location may be within the normal range in a different location (WMO).

A simple method is to establish a specific threshold for temperature and extreme precipitation events and evaluate the extremes that occur over (or under) that given threshold. Another common mean of ascertaining thresholds is based on selecting the tail of distributions for temperature and precipitation.Statistical partitions such as by quartiles or percentiles of the distribution have provided a means for evaluating extremes (WMO).

Facts and figures

Heat waves

A period of marked unusual hot weather (maximum, minimum and daily average temperature) over a region persisting at least three consecutive days during the warm period of the year based on local (station-based) climatological conditions, with thermal conditions recorded above given thresholds. Heat waves differ from warm spells. Similar to heat waves, warm spells are defined as a persistent period of abnormal warm weather. A warm spell occurs at any time of the year, whereas heat waves can only occur in the warm season (WMO).

Cold waves

A period of marked and unusual cold weather characterized by a sharp and significant drop of air temperatures near the surface (maximum, minimum and daily average) over a large area and persisting below certain thresholds for at least two consecutive days during the cold season. “Cool spell” refers to persistently below-average temperature conditions occurring during the warm season (WMO).

UN-SPIDER Regional Support Offices with hazard-specific expertise

Related content on the Knowledge Portal

  • Today, weather satellites scan the whole Earth, meaning not a single tropical storm or severe weather system goes undetected. The early detection and warnings they provide have saved thousands of lives.
    Meteosat data is of unique value to nowcasting of high impact weather in support of safety of life and property.
    It has been shown to improve weather forecasts and severe weather warnings which, in turn helps limit damage to property and benefits industry e.g. transport, agriculture and energy.
    Meteosat-11 is the prime operational geostationary satellite, positioned at 0 degrees and providing full disc imagery every 15 minutes. It also provides Search and Rescue monitoring and Data Collection Platform relay service.

    Instruments:
    GERB (Geostationary Earth Radiation Budget)
    MSG Comms (Communications Package for MSG)
    SEVIRI (Spinning Enhanced Visible and Infra-Red Imager)
     

    read more
    16/07/2015
  • The Sentinels are a fleet of satellites designed specifically to deliver the wealth of data and imagery that are central to the European Commission’s Copernicus programme.
    Sentinel-2 carries an innovative wide swath high-resolution multispectral imager with 13 spectral bands for a new perspective of our land and vegetation. The combination of high resolution, novel spectral capabilities, a swath width of 290 km and frequent revisit times provides unprecedented views of Earth.
    The mission is based on a constellation of two identical satellites in the same orbit, 180° apart for optimal coverage and data delivery. Together they cover all Earth’s land surfaces, large islands, inland and coastal waters every five days at the equator. Sentinel-2A was launched on 23 June 2015.
    As well as monitoring plant growth, Sentinel-2 can be used to map changes in land cover and to monitor the world’s forests. It also provides information on pollution in lakes and coastal waters. Images of...

    read more
    23/06/2015
  • Himawari 8 is a Japanese weather satellite, the 8th of the Himawari geostationary weather satellites operated by the Japan Meteorological Agency. The spacecraft was constructed by Mitsubishi Electric with assistance from Boeing, and is the first of two similar satellites to be based on the DS-2000 satellite bus. Himawari 8 entered operational service on 7 July 2015 and is the successor to MTSAT-2 (Himawari 7) which was launched in 2006.

    07/10/2014
  • Sentinel-1 is a two satellite constellation with the prime objectives of land and ocean monitoring. The goal of the mission is to provide C-Band Synthetic Aperture Radar (SAR) data continuity following the retirement of ERS-2 and the end of the Envisat mission.
    To accomplish this the satellites carry a C-SAR sensor, which offers medium and high resolution imaging in all weather conditiions. The C-SAR is capable of obtaining night imagery and detecting small movement on the ground, which makes it useful for land and sea monitoring.
    Sentinel-1 will work in a pre-programmed operation mode to avoid conflicts and to produce a consistent long-term data archive built for applications based on long time series.
    The mission benefits numerous services. For example, services that relate to the monitoring of Arctic sea-ice extent, routine sea-ice mapping, surveillance of the marine environment, including oil-spill monitoring and ship detection for maritime security,...

    read more
    03/04/2014
  • The Proba-V satellite may only be slightly larger than a washing machine, but it is tasked with a full-scale mission. This miniature satellite is designed to map land cover and vegetation growth across the entire globe every two days. Over the last decade 'Proba' has become synonymous with small high-performance satellites, designed around innovation. The two previous satellites in the series were demonstration missions to give promising technologies an early chance to fly in space. They were overseen by ESA’s Directorate of Technical and Quality Management. Although designed as a demonstration mission, the success of the first Proba satellite led to it being operated as an Earth observation Third Party Mission. Proba-1 carries a high-resolution imaging spectrometer. 

    ... read more
    07/05/2013
  • Gaofen-1 (gao fen = high resolution) is the first of a series of high-resolution optical Earth observation satellites of CNSA (China National Space Administration), Beijing, China. The civilian HDEOS (High-Definition Earth Observation Satellite) program was proposed in 2006, it received government approval and was initiated in 2010. China plans to launch six HDEOS spacecraft between 2013 and 2016. The major users of the observation data will be the Ministry of Land and Resources, Ministry of Environmental Protection, and the Ministry of Agriculture.
    The GF-1 spacecraft was launched on April 26, 2013 on a CZ-2D (Long March -2D) vehicle from the JSLC (Jiuquan Satellite Launch Center) in northwest China.

    Instruments:
    PMC (PAN and Multispectral camera)
    WFI (Wide Field Imager)

    26/04/2013
  • Landsat 8 launched on February 11, 2013, from Vandenberg Air Force Base, California, on an Atlas-V 401 rocket, with the extended payload fairing
 (EPF) from United Launch Alliance, LLC. The Landsat 8 satellite payload consists of two science instruments—the Operational Land Imager (OLI) and the Thermal Infrared Sensor (TIRS). These two sensors provide seasonal coverage of the global landmass at a spatial resolution of 30 meters (visible, NIR, SWIR); 100 meters (thermal); and 15 meters (panchromatic).
    Landsat 8 was developed as a collaboration between NASA and the U.S. Geological Survey (USGS). NASA led the design, construction, launch, and on-orbit calibration phases, during which time the satellite was called the Landsat Data Continuity Mission (LDCM). On May 30, 2013, USGS took over routine operations and the satellite became Landsat 8. USGS leads post-launch calibration activities, satellite operations, data product generation, and data archiving at the Earth...

    read more
    11/02/2013
  • Launched in December 2011, Pleiades is a constellation of two very-high-resolution satellites capable of acquiring imagery of any point on the globe in under 24 hours for civil and military users.
    Pleiades has been observing and mapping Earth’s surface at a resolution of just 70 cm every day since December 2011. Comprising the Pleiades 1A and Pleiades 1B satellites, this space imaging system complements the capabilities of the SPOT satellites, which have a wider field of view than Pleiades but lower spatial resolution. What’s more, as Pleiades 1A and 1B are in the same orbit, together they can image anywhere on Earth in less than 24 hours. Pleiades imagery is used for both civil and military applications, for example to track urban expansion, monitor the planet’s active volcanoes or assist road and railway routing, and to locate adversaries’ military installations for mission planning. Pleiades’ key asset is an extremely sensitive optical...

    read more
    01/12/2012
  • SJ-9 (Shi Jian = Practice) is a technology demonstration formation flight mission of CNSA (China National Space Administration), consisting of two minisatellites of different sizes and capabilities, SJ-9A and SJ-9B. The overall mission concept is to demonstrate the functionality of a range of newly developed formation flying techniques and components and to validate the formation flight GNC (Guidance, Navigation and Control) algorithms and strategies of the system configuration.
    SJ 9B carries the LWIR (Long Wave Infrared) Camera as a technology experiment. The goal of the LWIR camera is to test mainly the functions of the instrument such as the focal-plane component and the long-life Stirling cryocooler which is designed to function as an autonomic research and development component. The camera features low-temperature optics. The operational temperature of optical system is kept in the range of -35ºC to -20ºC.

    ...

    read more
    14/10/2012
  • VRSS-1 is Venezuela's first remote sensing satellite.
    On May 26, 2011, a contract for the manufacture and launch of the VRSS-1 spacecraft was signed in Caracas, Venezuela, between the government of Venezuela (the Ministry of People’s Power for Science, Technology and Intermediate Industries) and CGWIC (China Great Wall Industry Corporation), a subsidiary of CASC (China Aerospace Science & Technology Corporation).
    After launch, the VRSS-1 satellite was renamed in honor of Sebastián Francisco de Miranda (1750-1816), a Venezuelan revolutionary hero, known as ‘Generalissimo’ Francisco de Miranda, who had planned the independence of the Spanish colonies in South America.
    Partner organizations in the VRSS-1 program: ABAE is the Space Agency of Venezuela, subordinated and funded by the Venezuelan Ministry of People’s Power for Science, Technology and Innovation (MPPCTI). ABAE is in charge of in-orbit operations, management and application of...

    read more
    20/09/2012

Term Parents

UN-SPIDER Regional Support Offices with hazard-specific expertise