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Dataset

 

CLASSnmat version 2: monthly, global, gridded night marine air temperature data

Update Frequency: Not Planned
Latest Data Update: 2025-05-14
Status: Ongoing
Online Status: ONLINE
Publication State: Citable
Publication Date: 2025-05-09
DOI Publication Date: 2025-05-14
Download Stats: last 12 months
Dataset Size: 3.86K Files | 9GB
Abstract

Climate Linked Atlantic Sector Science (CLASS)nmat is a global dataset of monthly mean night marine air temperature (NMAT) that is produced on a 5° latitude by 5° longitude regular grid and covers the period since 1880.

The temperature values are taken from version 3.0.0 of the International Comprehensive Ocean-Atmosphere Data Set (ICOADS) for the period 1880-2014 and from version 3.0.2 of ICOADS thereafter. The in situ air temperature readings recorded between one hour after sunset and one hour after sunrise have been extracted from ICOADS and the ship data have been adjusted to reduce the effects of varying thermometer heights. The data have been adjusted from their respective recording heights to each of three reference heights: 2m, 10m and 20m. The air temperature readings have been subjected to a quality-control procedure and then the values have been aggregated to form gridded averages, with corresponding uncertainty estimates.

This dataset has been developed under the following NERC-funded projects: GloSAT (NE/S015647/2), CLASS (NE/R015953/1) and AtlantiS (NE/Y005589/1).

Citable as:  Cornes, R.C.; Cropper, T.; Kent, E.C. (2025): CLASSnmat version 2: monthly, global, gridded night marine air temperature data. NERC EDS Centre for Environmental Data Analysis, 14 May 2025. doi:10.5285/306246329ae04eb3b2299446d911530a. https://dx.doi.org/10.5285/306246329ae04eb3b2299446d911530a
Cite this dataset

Abbreviation: Not defined
Keywords: CLASS, temperature, marine, global

Details

Previous Info:
No news update for this record
Previously used record identifiers:
No related previous identifiers.
Access rules:
Public data: access to these data is available to both registered and non-registered users.
Use of these data is covered by the following licence(s):
http://www.nationalarchives.gov.uk/doc/open-government-licence/version/3/
When using these data you must cite them correctly using the citation given on the CEDA Data Catalogue record.
Data lineage:

In version 2 of CLASSnmat the following changes have been made to the construction of the dataset:
- Ship Data from additional sources to ICOADS have been used
- A refined Quality Control (QC) procedure has been used
– An ensemble version of the Cornes et al. (2020) error model has been developed to produce a 200-member ensemble dataset

Details of these changes are documented in Morice et al. (2024).

Data were produced by the project team and supplied for archiving at the Centre for Environmental Data Analysis (CEDA).
File Format:
Data are NetCDF formatted

Related Documents

 CLASSnmat: A global night marine air temperature data set, 1880–2019
 Morice, C. P., Berry, D. I., Cornes, R. C., Cowtan, K., Cropper, T., Hawkins, E., Kennedy, J. J., Osborn, T. J., Rayner, N. A., Rivas, B. R., Schurer, A. P., Taylor, M., Teleti, P. R., Wallis, E. J., Winn, J., and Kent, E. C.: An observational record of global gridded near surface air temperature change over land and ocean from 1781, Earth Syst. Sci. Data Discuss. [preprint], https://doi.org/10.5194/essd-2024-500, in review, 2024.

Process overview

This dataset was generated by the computation detailed below.
Title

CLASSnmat: a monthly, global, gridded night marine air temperature data
Abstract

The temperature values are taken from version 3.0.0 of the International Comprehensive Ocean-Atmosphere Data Set (ICOADS) for the period 1880-2014 and from version 3.0.2 of ICOADS thereafter. The in situ air temperature readings recorded between one hour after sunset and one hour after sunrise have been extracted from ICOADS and the ship data have been adjusted to reduce the effects of varying thermometer heights. The data have been adjusted from their respective recording heights to each of three reference heights: 2m, 10m and 20m. The air temperature readings have been subjected to a quality-control procedure and values that fail these tests have been excluded. Duplicate values have also been excluded. Additional adjustments have been applied to the data during the Second World War to account for non-standard thermometer exposures on some ships.
The adjusted data have been aggregated into monthly mean values in each grid-cell; uncertainty estimates of these gridded values are also provided. The data have not been interpolated across missing grid boxes. In addition to the absolute temperature values, the gridded data also contain anomalies that are expressed with respect to three climatological averages (1961-90, 1971-2000 and 1981-2010).
Input Description

None
Output Description

None
Software Reference

None
  • units: K2
  • var_id: covariance
  • long_name: Error covariance of air-temperature
  • standard_name: air_temperature
  • units: degrees Celsius
  • var_id: t10m_anomaly
  • var_id: bnds
  • long_name: bnds
  • units: degrees_north
  • var_id: latitude_vector_1
  • var_id: latitude_vector_1_bnds
  • units: degrees_north
  • var_id: latitude_vector_2
  • var_id: latitude_vector_2_bnds
  • long_name: location_index_1
  • var_id: location_index_1
  • long_name: location_index_2
  • var_id: location_index_2
  • units: degrees_east
  • var_id: longitude_vector_1
  • var_id: longitude_vector_1_bnds
  • units: degrees_east
  • var_id: longitude_vector_2
  • var_id: longitude_vector_2_bnds

Co-ordinate Variables

  • units: degrees_north
  • standard_name: latitude
  • var_id: latitude
  • long_name: latitude
  • units: degrees_east
  • standard_name: longitude
  • var_id: longitude
  • long_name: longitude
  • long_name: time
  • standard_name: time
  • var_id: time
  • units: days
Coverage
Temporal Range
Start time:
1880-01-01T00:00:00
End time:
Ongoing
Geographic Extent

 
90.0000°
  
-180.0000°
  
180.0000°
 
-90.0000°
  
Related parties
Authors (3)
Publishers (1)
Funders (4)
Principal Investigators (2)