Documentation

This page contains the documentation for the CRU TS 1.2 data-set, and comprises:

Data
The CRU TS 1.2 data-set is available as an archive: cru_ts_1.20.zip

Full range of data-sets
If you have arrived at this page from a different website (without the red frame), you may be interested in the wider range of high-resolution climate grids available here. There is a table detailing the full range of data-sets. For example, there are 16 GCM-based scenarios for the 21st century on the same 10 minute grid (TYN SC 1.0).

Updates

4th August 2003
The reference for this data-set has been updated to: Mitchell, T.D., Carter, T.R., Jones, P.D., Hulme,M., New, M., 2003: A comprehensive set of high-resolution grids of monthly climate for Europe and the globe: the observed record (1901-2000) and 16 scenarios (2001-2100). Journal of Climate: submitted.

2nd May 2003
A new software page gives users the opportunity to share software for manipulating these climate grids, and reinvent the wheel less frequently!

1st May 2003
The issue of using the observed grids for time-series analysis has been addressed more explicitly and fully. A separate page discusses time-series analysis. This has been written with the successor data-set CRU TS 2.0 in mind, but the issues discussed there are the same here. For more information, see under Guidance.

1st April 2003
An elevations file (540 KB, compressed) has been provided. (The land-sea mask is implied.)

4th February 2003
Data-set publicly released, as version 1.20.

Introduction
The CRU TS 1.2 data-set comprises 1200 monthly grids of observed climate, for the period 1901-2000, and covering the European land surface at a 10 minute resolution. There are five climatic variables available: cloud cover, DTR, precipitation, temperature, vapour pressure.

It was New et al (2000) who were responsible for the original high-resolution (0.5 degree) climate grids (CRU TS 1.0) and an update to 1998 (CRU TS 1.1). See the table for more details of those data-sets. This data-set extends those data-sets to 2000 for Europe only, and at 10 minute (spatial) resolution. The same basic methodology was used as described in New et al (2000).

Guidance
The primary purpose for which this data-set was constructed was to provide environmental modellers with some of the inputs they require to run their models. This purpose governed the choices that were made during the construction of the data-set. The methodology we used affects how the data-set should be used.

The issues involved in using CRU TS 1.2 for time-series analysis are addressed more explicitly and fully. This has been written with the successor data-set CRU TS 2.0 in mind, but the issues discussed there are the same here. We recommend that all users who intend to examine climate change using this data-set should consider the issues carefully before beginning their work. The most important difference from CRU TS 2.0 is that no comparable station files have been released for CRU TS 1.2. This is because this data-set is based on previously constructed grids (CRU TS 1.0 and CRU TS 1.1) for which I was not responsible.

The companion data-set TYN SC 1.0 may be used to extend the period available from 2000 to 2100, through 16 climate change scenarios.

This data-set was a precursor to the global revision of the CRU TS product, available as CRU TS 2.0 This data-set is most appropriately used in conjunction with TYN SC 1.0, to provide high-resolution climate scenarios for 1901-2100. Any user who is considering using this data-set instead of CRU TS 2.0 should weigh up the benefit of the increased spatial resolution against the poorer version of the observed record.

The only changes to this data-set, compared to CRU TS 1.0 and CRU TS 1.1, were as follows:

  • The month-to-month variations for 1996-2000 (1999-2000 for pre and tmp) were interpolated onto a 0.5 degree grid.
  • These grids were combined with CRU TS 1.0 and CRU TS 1.1, and then smoothed onto the 10' grid.
  • The 10' grids were combined with the climatology at 10' (CRU CL 2.0 and CRU CL 2.1), rather than 0.5 degrees.

Data Structure
At present, the data-set is only available in the form of large ASCII files (one per variable). They are designed for use on a Unix system, not in Excel! I will try to provide this data-set in some other forms when I have some time. You will need the file format details. There is also a software page.

Ownership
The creator of this data set (Dr. T. D. Mitchell) retains full ownership rights over it. The data set may be freely used for non-commerical scientific and educational purposes, provided it is described as CRU TS 1.2 and attributed to:

Mitchell, T.D., Carter, T.R., Jones, P.D., Hulme,M., New, M., 2003: A comprehensive set of high-resolution grids of monthly climate for Europe and the globe: the observed record (1901-2000) and 16 scenarios (2001-2100). Journal of Climate: submitted.

Disclaimer
The author of this data-set cannot bear any responsibility for the consequences of using it, which are entirely the responsibility of the user. It is inevitable that a data-set of this size will contain some errors and inconsistencies. However, these have been kept to a minimum and when they are identified they are corrected when resources permit. Updates to this data-set will be notified on this web page and by email to registered users.

Further Information

  • A brief introduction to the methods used in constructing the data-set is available in the release document.
  • A set of plots give some example time-series.
  • See the FAQ.
  • The elevations (540 KB, compressed) of the grid are available. (The land-sea mask is implied.)
  • If you have arrived at this page from a different website (without the red frame), you may be interested in the wider range of high-resolution climate grids available here. There is a table detailing the full range of data-sets.