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EU Surface Temperature for All Corners of Earth

Periodic Reporting for period 3 - EUSTACE (EU Surface Temperature for All Corners of Earth)

Reporting period: 2017-04-01 to 2019-03-31

Day-to-day variations in surface air temperature affect society in many ways, but daily surface air temperature measurements are not available everywhere. EUSTACE has utilised Europe’s capacity for gathering space-borne observations of the skin temperature of Earth’s surface by extracting the information relevant to providing estimates of surface air temperature. Surface air temperature is measured at often sparse meteorological (or weather) stations. Skin temperature is the temperature of the top few microns of the ground beneath our feet, of the ocean or of the polar ice caps and sea ice. EUSTACE has extracted this information from the measurements from different satellites to enable estimates of surface air temperature to be made over all surfaces of Earth at higher spatial and temporal resolution than previously possible. It has then combined this information with measurements made at weather stations and at sea to create global fields of surface air temperature, where these can be reliably estimated.

EUSTACE has developed global and European, multi-decadal ensembles of daily analyses of surface air temperature complementary to those from dynamical reanalyses, integrating different ground-based and satellite-borne data types. Relationships between surface air temperature measurements and satellite-based estimates of surface skin temperature over all surfaces of Earth (land, ocean, ice and lakes) have been quantified. Information contained in the satellite retrievals then helped to estimate air temperature and create global fields in the past, using statistical models of how surface air temperature varies in a connected way from place to place; this needs efficient statistical analysis methods to cope with the considerable data volumes. Daily fields are presented as ensembles to enable propagation of uncertainties through applications. Estimated temperatures and their uncertainties were evaluated against independent measurements and other surface temperature data sets.
Work carried out and key findings:
• Detecting and correcting for non-climatic discontinuities in weather station series worldwide: to provide an accurate picture of variations in air temperature, EUSTACE has checked measurements at weather stations for any jumps in the series
• Creating an improved set of station measurements and gridded fields of daily air temperature for Europe, where non-climatic discontinuities have been removed;
• Estimating consistent skin temperature uncertainties: because EUSTACE has used different satellite data on the surface skin temperature of the land, ocean and ice, EUSTACE has derived consistent uncertainty estimates for these data
• Estimating air temperature from satellite: while in some locations air temperature records can span periods of a century or more, in many areas there is a lack of information. EUSTACE has increased the amount of information available in some sparsely observed regions by understanding and exploiting the relationship between surface skin temperature and surface air temperature
• Understanding the role of lakes: a number of studies explored various aspects of the relationship between lake surface water temperature and air temperature and shed more light on the place of lakes in the global climate system.
• Estimating complete fields: EUSTACE used cutting-edge statistical methods to exploit the links between air temperature in different places and through time to estimate daily air temperatures where and when neither direct measurements, nor estimates from satellite are available

The final products from EUSTACE (https://catalogue.ceda.ac.uk/uuid/a52b2cc065a847b8a77a93896880349f) are:
• Global land station daily air temperature measurements with non-climatic discontinuities identified, for 1850-2015
• European land station daily air temperature measurements, homogenised
• Gridded European surface air temperature based on homogenised land station records since 1950: dataset of daily air temperatures from 1950 onwards (E-OBS, by interpolation)
• Global clear-sky land, ice, and sea surface temperatures from satellites with estimates of uncertainty components
• Globally gridded clear-sky daily air temperature estimates from satellites with uncertainty estimates for land, ocean and ice, 1995-2016
• Information on the relationship between skin and air temperature over different domains and different seasons (see the Scientific User Guide)
• Global daily air temperature combining surface and satellite data, with uncertainty estimates, for 1850-2015
• Coincident daily air temperature estimates and reference measurements, for validation, 1850-2015

In addition EUSTACE has produced:
• User requirements reports via continual engagement of the user community, including “trail blazer” users who have been involved in the design of products;
• Product and Scientific user guides;
• Statistical models relevant to non-Gaussian variables and methods for efficient computation; and
• Peer-reviewed journal articles.
"EUSTACE made progress beyond the state of the art by:
• Producing the first global daily analysis using satellite and in situ data, that is not a dynamical reanalysis;
• Incorporation of homogenisation into the statistical analysis;
• Taking a consistent approach to estimating uncertainties on satellite skin temperature data sets, split into components;
• Validating uncertainty estimates;
• For the first time, calculating 2m air temperature from satellite over sea ice. First data set of air temperature over all ice covered surfaces together;
• Providing the first global daily station data set with estimated locations of non-climatic discontinuities and their likelihood and a pan-European station data set, homogenised to reduce the impact of non-climatic discontinuities.

EUSTACE will innovatively help to enable Europe (and elsewhere) to address several societal challenges through the provision of information:
• important to health research;
• important to agricultural and forestry research;
• important to enable understanding of the efficiency of renewable energy generation;
• e.g.: understanding past surface air temperature variability, ranges and extremes, important to understanding how to develop infrastructure robust to climate variability;
• to understand surface air temperature impacts on resilience to natural disasters and to understanding potential future climate-related events affecting other parts of the world; and
• to evaluate other information on climate variability and change, such as seasonal-to-decadal forecasting systems, dynamical reanalysis, Earth System Models, and climate impacts information.

Images:
EarthTemp-Scenery.png
EUSTACE used the relationships between Ice Surface Temperature (IST), Land Surface Temperature (LST), Land Surface Air Temperature (LSAT), Sea Surface Temperature (SST), Marine Air Temperature (MAT) and Lake Surface Water Temperature (LSWT) to combine these different types of measurement to produce global daily analyses of surface air temperature over all surfaces. Figure taken from Merchant et al., 2013.
Reference: Merchant, C.J. et al (2013) “The surface temperatures of Earth: steps towards integrated understanding of variability and change.” Geosci. Instrum. Method. Data Syst., 2, 305-321, doi:10.5194/gi-2-305-2013

eustaceFig.png
Reference: Rayner, N.A. et al (2019) ""The EUSTACE project: delivering global, daily information on surface air temperature"", submitted to BAMS
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An infographic summarising the EUSTACE project
Summary of the links between different components of the EUSTACE project and its products.
Image of relationships between different types of temperature measurement