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Questions: SST/SIC Boundary data for CAM5

J

jbh@tsinghua_edu_cn

New Member
Hi, everybody, I am a newcomer for CAM5 simulation. Now, I face many problems/questions with CAM5 running.
Firstly, I know Hurrell et al.(2008) data is usually used for AMIP style uncoupled simulations. I checked this data and found SST and SIC are distributed globally, that means there are values of SST and SIC over continents, which also evolve with time. The first question is that why there are values of SST and SIC over continents and are they necessary and used in CAM5 simulation? If not, why they evolve with time? Are there some rules for the SST/SCI values over land?

Secondly, I compared the Hurrell et al.(2008) dataset with the observations from Hadley Centre. Some differences exist in sea ice variation between these two datasets. So, which one is better? And, if I want to use the observed SST/SIC of Hadley Centre to force CAM5, how can I prepare the boundary data? Can the boundary data be done by replacing the SST/SCI of ocean in Hurrell et al. (2008) dataset with the counterpart in Hadley dataset ?

Thirdly, I read many papers about simulations forced by sea ice, which based on Hurrell et al.(2008) data. If I do some modification to the SIC over ocean, must I do similar modifications to the SIC over land? For example, I made a sea ice boundary condition by detrending the SIC over ocean, should I do similar process to the SIC over land?

Very appreciated for any suggestions and advices!

 
hannay

hannay

Cecile Hannay
AMWG Liaison
Staff member
The SST and SIC are interpolated over land. It is necssaey for the model to have values over land otherwise, it will crash bu the values overl land don't impact the simulation. 
The Hurrell dataset is specifically created for use with CAM5 and include the "diddling" procedure that ensures that the monthly mean of the daily-interpolated SST anomalies matches the monthly SST anomalies. This follows the protocol for AMIP simulation described in:
Taylor, K.E., D. Williamson, and F. Zwiers (2000): The sea surface temperature and sea-ice concentration boundary conditions for AMIP II simulations. PCMDI Report No. 60 and UCRL-MI-125597, Lawrence Livermore National Laboratory, Livermore, CA, 25 pp.
pdf file available at  http://www-pcmdi.llnl.gov/publications/pdf/60.pdf

This "diddling" is done with icesst tools. The icesst tools is available at:
ftp://ftp.cgd.ucar.edu/archive/icesst/
The icesst code allows to build CAM-readable SST and sea ice concentration boundary datasets at an arbitrary resolution. This tool is not supported and we are sharing it "as is" 
 
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