Documentation

This page contains the documentation for the TYN SC 2.0 data-set, and comprises:

Data
The TYN SC 2.0 data-set is available to download.

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 observed time-series for the 20th century on the same 0.5 degree grid (CRU TS 2.0).

Updates

2nd February 2004
The version number has been updated to 2.03, because an additional GCM (ECHam4) has been added to the set of GCMs represented, bringing the number of GCMs to five, and the total number of scenarios to 20.

4th August 2003

  • A new self-service unpacking page gives users the opportunity to unpack the scenarios without using the fortran software supplied. This should broaden the range of people for whom the data-set is usable.
  • The version number has been updated to 2.02, reflecting corrections made to the PCM B1 and B2 scenarios.
  • 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.

13th May 2003
An elevations file for the 0.5 degree grid used here is now available. This file also implicitly describes the land-sea mask, since only land boxes are given elevations. The file format is the same as that of the data files.

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!

10th February 2003
This data-set has been summarised in the form of graphics showing the range of 21st century climate changes that may be experienced by each individual country, as represented by the 16 climate change scenarios in this data-set. See TYN CY 3.0.

4th February 2003
Data-set publicly released, as version 2.01.

Introduction
The TYN SC 2.0 data-set comprises monthly grids of modelled climate, for the period 2001-2100, and covering the global land surface at 0.5 degree resolution. There are five climatic variables available: cloud cover, DTR, precipitation, temperature, vapour pressure. There is one control scenario and 20 climate change scenarios, which should be treated as equally likely.

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.

  • The control scenario represents the evolution of surface climate over the 21st century under the assumption that the mean climate remains fixed at 1961-90 levels.
  • The 20 climate change scenarios are made up of all permutations of five models with four SRES emissions scenarios (A1FI, A2, B2, B1).
  • The month-to-month and year-to-year variations are superimposed on top of the averaged climate changes taken from the models; these variations are taken from the gridded observations in CRU TS 2.0.
The companion data-set CRU TS 2.0 may be used in conjunction with TYN SC 2.0 to provide complete time-series for the period 1901-2100. The control scenario for the 21st century may be duplicated into the 20th century, which provides a time-series for the period 1901-2100 without any long-term climate change.

The purpose of providing 20 different futures is to enable environmental modellers to represent the uncertainty in climate impacts arising from two distinct sources of uncertainty: uncertainty in the future emissions of greenhouse gases, and uncertainty in climate modelling. Each of the 20 permutations should be treated as equally likely. Between them, the 20 scenarios cover 93% of the possible range of future global warming estimated by the IPCC in their Third Assessment Report (2001). The control scenario may be useful for tuning models, and for establishing baselines.

This data-set is complemented by TYN SC 1.0, which is very similar to this data-set, but is at a higher spatial resolution (10') and extends to the European land mass only.

For many purposes, it is better to use this data-set than to use direct model outputs:

  • There is complete consistency between the observed (20th) and estimated (21st) centuries, which can only be obtained with direct model outputs by assuming that the modelled 20th century matches the observed 20th century.
  • There is complete consistency between each of the emissions scenarios. In many cases, modelling centres have only performed and released simulations for one or two of the 'marker' SRES scenarios, but not for them all. This data-set provides the same information for each of the four 'marker' SRES scenarios.
  • There is complete consistency between each of the climate models. The direct model outputs are generally available only on the native grids, which vary between models. Also, different models report different climatic variables. This data-set provides the same information for each of the four GCMs included.
The net effect of these advantages is that it becomes much easier to conduct systematic investigations into the future of the environmental system being modelled.

Data Structure
This data-set is very large. To reduce data transfer volumes, the data-set is supplied in the form of a set of raw ASCII files, which must then be unpacked into the scenarios. Please bear in mind that the scenarios are designed for use on a Unix system, not in Excel! There are two approaches to unpacking: use the supplied fortran software, or carry out the unpacking yourself. The readme file provides further information about the file structure. The unpacking procedure is explained here. You will need the file format details. There is also a user-supplied software page.

WARNING! The raw data files are USELESS without the unpacking procedure. Do NOT attempt to directly use these raw data files. Your results will be WRONG! Use the unpacking procedure.

An elevations file for the 0.5 degree grid used here is available. This file also implicitly describes the land-sea mask, since only land boxes are given elevations. The file format is the same as that of the data files.

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 TYN SC 2.0 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.
  • The range of the scenarios is illustrated by plots of the time-series of global warming across 16 scenarios, and broken down by model. These plots were produced before ECHam4 was added.
  • See the FAQ.
  • 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.
There is some further relevant information available for the TYN SC 1.0 data-set.

Models
The four models used in this data-set are among the set of state-of-the-art coupled climate models used by the IPCC (2001) in the Third Assessment Working Group 1 Report. Further details about the individual models may be obtained from that report (Tables 8.1 and 9.1).


model short IPCC number
CGCM2 CCCma 7
CSIRO mk 2 CSIRO2 10
DOE PCM PCM 30
HadCM3 UKMO 23
ECHam4 ECHam4 15