Climatological or fixed boundary conditions
This issue is related to the input data sets to TM5 to be used for EC-Earth.
For some variables, including anthropogenic and biomass burning emissions as well as stratospheric ozone and global surface methane concentrations, long-term transient data sets will be provided by CMIP6. These should be applied in the model. In addition, the stratospheric methane concentrations can be assumed to follow the methane concentrations at the surface by applying a year dependent scaling factor.
For the other input data sets, we can either apply climatologies or use a fixed reference year, e.g. 2010. These variables include biogenic and other natural emission sources, for which various data sets are used:
- Non-LPJ methane emissions from HYMN and natural emissions from MACC are provided as climatologies. It is recommended to remove the year label in the MACC file names.
- Biogenic emissions from MEGAN and methane emissions from peatlands, wetlands and wet soils from LPJ include inter-annual variability, and need further processing for use in long-term simulations.
- Soil uptake of methane is based on monthly uptake rates from the LPJ data set (the uptake rates per ppm methane from the lpj_soilconsumption-perconc*.nc files are used). The rates have some inter-annual variability, and would need processing for building a climatology.
#2 Updated by Philippe Le Sager about 6 years ago
On 09/02/2015 05:19 PM, Narcisa Banda wrote:
The natural emissions from MACC are already climatological. As far as I know, they are the same every year. So you can just use a fixed year, doesn’t matter which one. Also HYMN are climatologies, except for LPJ.
#3 Updated by Anonymous about 6 years ago
Annually and monthly varying uptake rates are used for soil consumption from LPJ.
For the MACC emission files, they also contain biomass burning and anthropogenic emissions, which are annually varying. So it would be better to move the natural MACC climatologies into separate files.
#4 Updated by Twan van Noije over 5 years ago
Rather than creating climatologies of natural emissions, we agreed that we can simply use emissions for a specific year. For methane emissions from wetlands, Michiel recommended to use fields from LPJ, which have little inter-annual variability. For biogenic emissions from MEGAN-MACC this is also a valid approach and for the natural emissions from MACC it doesn’t matter, as these are the same for each year. The easiest way to achieve this, is simply by restricting the time interval for which the corresponding emissions fields are supposed to be available to a single year, e.g. the year 2000.
#5 Updated by Twan van Noije over 4 years ago
I have included a new flag in the rc-file that allows to use a fixed year for the LPJ CH4 input data, natural emissions from MACC, and biogenic emissions from MEGAN:
input.natemis.year : <year>
For climate integrations, it is recommended to set it to 2000.
If commented, the same year will be used for natural emissions as for anthropogenic and biomass burning sources.