For a fuller description of the paper itself, go to the end of this web page.
Each simulation published in this paper corresponds to a unique 5 or 6 character code on the web pages.
The following table lists the name of the simulation as used in the paper, and the corresponding code name
The webpage gives you the ability to examine the published simulations, but you can also download the raw (netcdf) files to perform your own analysis. Detailed instructions on how to use the webpages and access the data can be found here: Using_BRIDGE_webpages.pdf
You can have make you own analysis and plots by going here
| Name of sequence of simulations as in Paper | Simulation sequence name as in web pages | Detailed description of individual simulations within sequence |
|---|---|---|
| bham_holocene_std - HadCM3BM2.1d transient simulations - 30 year mean climatologies taken every 500 years | bham_holocene_std | Detailed List of Runs |
| bham_holocene_conv - as std but updated convection parameters | bham_holocene_conv | Detailed List of Runs |
| bham_holocene_vms - as std but updated vegetation moisture stress parameters | bham_holocene_vms | Detailed List of Runs |
| bham_holocene_convvms - as std but with updated convection and vegetation parameters | bham_holocene_vmsconv | Detailed List of Runs |
This paper presents 4 transient Holocene simulations with the coupled HadCM3-M21d model. Four different configurations test the role of palaeo-climate informed updates to the parameterisations for convection and vegetation, and the two together. The results show how these can improve the simulation of the abrupt desertification of the Sahara during the Holocene which most GCMs have failed to replicate before.
| Name | Hopcroft and Valdes |
|---|---|
| Brief Description | This paper presents 4 transient Holocene simulations with the coupled HadCM3-M21d model. Four different configurations test the role of palaeo-climate informed updates to the parameterisations for convection and vegetation, and the two together. The results show how these can improve the simulation of the abrupt desertification of the Sahara during the Holocene which most GCMs have failed to replicate before. |
| Full Author List | Hopcroft PO, and Valdes PJ |
| Title | Palaeoclimate conditioning reveals a North Africa land-atmosphere tipping poing |
| Year | 2021 |
| Journal | PNAS |
| Volume | 118(45) |
| Issue | |
| Pages | e2108783118 |
| DOI | 10.1073/pnas.2108783118 |
| Contact's Name | Peter Hopcroft |
| Contact's email | p.hopcroft@bham.ac.uk |
| Abstract | While palaeoclimate records show that the Earth System is characterised by several different tipping points, their representation within Earth System models (ESMs) remains poorly constrained. This is because historical observations do not encompass variations large enough to provoke such regime-changes and paleoclimate conditions are rarely used to help develop and tune ESMs, which potentially ignores a rich source of information on abrupt climate change. A critical example is the early- to mid-Holocene ’greening’ and subsequent rapid desertification of the Sahara which most ESMs fail to reproduce, casting doubt on the representation of land-atmosphere coupling and monsoon dynamics. Here we show that this greening and abrupt termination can be successfully simulated with one ESM after optimising uncertain model components using both present day observations and crucially mid-Holocene (6,000 years before present) reconstructions. The optimised model displays new abrupt threshold behaviour which shows excellent agreement with long palaeoclimate records that were not used in the original optimisation. These results suggest that in order to realistically capture climate system thresholds, ESMs first need to be conditioned with appropriate palaeoclimate information. |