Extreme Temperature

The image shows the heat emanating from Death Valley on 30 June 2013. The measurement is surface temperature as measured by the Thermal Infrared Sensor on the Landsat 8 satellite. The accompanying natural color view from the Operational Land Imager on Landsat 8 shows that the cooler areas are either higher in elevation or covered with plants. Image: NASA.

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).

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Related content on the Knowledge Portal

Event

Satellite Remote Sensing for Agricultural Applications logo. Image: NASA

This four-part introductory webinar will focus on data products, data access, and case-studies demonstrating how remote sensing data can be used for decision-making among the agriculture and food security communities.

This training will address how to use remote sensing data for agriculture monitoring, specifically drought and crop monitoring. The webinar will also provide end-users the ability to evaluate which regions of the world agricultural productivity is above or below long-term trends. This informs decisions pertaining to market stability and humanitarian relief.

By the end of this training, attendees will be able to:
  • Identify which satellites and sensors can be used for agricultural applications
  • Understand the limitations of remote sensing and modeled data for agriculture and food security
  • Acquire specific remote sensing data products that are appropriate for their work
  • Apply remote sensing techniques to crop monitoring,... read more
Image: NASA.

This webinar will focus on a NASA instrument that was launched and installed on the International Space Station in summer 2018. Designed to study terrestrial ecosystems and plant water stress from the ISS, ECOSTRESS can also be used to better understand crop health, volcanoes, urban heat, wildland fires, coastal systems, and much more. 

The primary science and applications mission of ECOSTRESS is to address three critical questions around vegetation health and agriculture:

  1. How is the terrestrial biosphere responding to changes in water availability?
  2. How do changes in diurnal vegetation water stress impact the global carbon cycle?
  3. Can agricultural vulnerability be reduced through advanced monitoring of agricultural water consumptive use and improved drought estimation?
... read more

Free webinar from the Applied Remote Sensing Training (ARSET) programme at NASA to identify remote sensing data and tools relevant to tropical storms, monitor conditions before, during, and after a storm using remote sensing data, understand how remote sensing data can be used in decision-making activities.

Tropical storms have major impacts, including loss of life and destruction of property. In 2017 alone, the United States experienced three tropical storms with more than $1 billion in losses. Open source satellite data can be used before, during, and after a storm for monitoring and response. A storm’s intensity, path, wind, precipitation, storm surge, and flooding can be derived from historical and near real-time satellite observations. In this introductory webinar, participants will learn about the NASA data and tools they can use to monitor tropical storms.

News

Dzud risk map. Image: information and Research Institute of Meteorology Hydrology and Environment

The Mongolian National Agency for Meteorology and Environmental Monitoring (NAMEM) has developed a extreme winter (dzud) risk map for the country using MODIS satellite data, among other resources. The map shows that over 50 per cent of the country are at risk of a severe winter. Following the analysis, the International Federation of the Red Cross and Red Crescent Societies (IFRC) has released funds to limit the impact on vulnerable herders. The early action move is carried out under the Disaster Relief Emergency Fund (DREF) forecast-based financing (FbF) approach, an early action protocol under which funds are released ahead of a disaster to limit its impact. 

NAMEM developed the dzud risk map using 11 different parameters based on remote sensing data collected from MODIS satellite, such as snow cover and drought index, and on ground observation data, including summer condition, anomalous precipitation and temperature, snow depth, air temperature... read more

Publishing date: 19/02/2020

Major disasters such as droughts and wildfires are driven by the dryness of vegetation. To enhance the monitoring of plant water stress, NASA launched and installed a new sensor on the International Space Station. ECOSTRESS (ECOsystem Spaceborne Thermal Radiometer Experiment on Space Station) allows identifying loss of water in leaves- even before they show visible signs of trouble.

The image to the left shows a product derived from ECOSTRESS data, indicating that the forest fires during the 2019 Amazon dry season were concentrated in water-stressed areas, which are not visible on optical imagery. “To the naked eye, the fires appear randomly distributed throughout the forest,” said Josh Fisher, ECOSTRESS science lead at NASA’s Jet Propulsion Laboratory.

Plants regulate their... read more

Publishing date: 14/11/2019
Damage from a 7.4 earthquake and a tsunami that hit the Indonesian island of Sulawesi on 28 September 2018. Image: European Union/Pierre Prakash/Flickr.

In the past year, “there were 315 natural disaster events recorded with 11,804 deaths, over 68 million people affected, and US$131.7 billion in economic losses around the world.” This is according to the Centre for Research on the Epidemiology of Disasters (CRED) in its recently released 2018 Natural Disasters Report

While these 2018 natural disaster values represent a decrease when compared with the annual averages from 2008 to 2017, some geographic areas still experienced great losses of life and damages due to natural hazards. Indonesia was most adversely impacted in terms of lives claimed, with earthquakes in August and September 2018 that left a total of 4,904 people dead or missing, according to the CRED. Earthquakes also accounted for the greatest number of deaths among natural disasters worldwide in 2018. And among all types of natural hazards, floods affected the greatest number of people during the past... read more

Publishing date: 01/07/2019

Data Source

Publishing institution: Geoscience Australia
The Digital Earth Africa (DE Africa) Map is a website for map-based access to spatial information. It’s is still being developed by Data61 CSIRO in collaboration with Geoscience Australia. DE Africa is leveraging international Earth Observation (EO) data and science to produce new information and services that benefit African countries. Through translating data into ready-to-use insights, more informed decisions about soil and coastal erosion, agriculture, deforestation, desertification, water quality and changes to human settlements can be made. The data is organized in data-cubes and will be fully available by 2020.

GP-STAR factsheet

Schematic Workflow for the derivation of an exemplary Sendai indicator using crisis information generated from satellite remote sensing (Source: own figure; Copernicus Emergency Management Service (©European Union), EMSN024, EMSN056)
Publishing institution: German Federal Office of Civil Protection and Disaster Assistance

To meet the global challenges, the United Nations adopted several framework agreements, including the Sendai Framework for Disaster Risk Reduction at the Third United Nations World Conference on Disaster Risk Reduction (2015-2030). The framework builds the international reference point for disaster preparedness and focuses on reducing existing and future disaster risks as well as enhancing disaster resilience. In the Sendai framework, seven global targets have been agreed to measure global progress in implementing the framework through quantifiable indicators and to present, compare and evaluate the status and progress uniformly worldwide. The recording of the status and degree of target achievement using the agreed indicators requires the use of various data sources, which must be consistent and comparable in time and space in order to ensure global monitoring.

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