Experimental tag for cesm1.5 Tag for 28 (mini-breck code) 28 code is 4-month old Tag for 36 (modern version of the code base) Purpose: Up-to-date code base We expect differences in climate because there are differences in the code.

What are the differences 28  36 ? 28 code 36 code Differences cime cime4.2.3_cntlexp.06 cime4.4.5_cntlexp.06 cam cam5_4_29 cam5_4_51 mods to energy conservation fixer WACCM updates (se grid, gravity wave drag consistent with CCMI, fix for troposphere/stratosphere heterogeneous chemistry rates) clm respmods_n06_clm4_5_7_r162 respmods_n11_clm4_5_7_r169 minor updates to the nitrogen code bug fix to the methane code Both affect plant productivity and biogeophysical properties of the surface cice cice5_20151113 cice5_20160219 SW bug fix pop cesm_pop_2_1_20151215 cesm_pop_2_1_20160222 compute the surface layer depth to be 10% of the boundary layer cism cism2_1_10 cism2_1_13 Nothing important ;) ww3 ww3_151016 mosart mosart1_0_14 mosart1_0_16 bug fixes which could change discharge for some rivers. Expected to be similar to 28.

36 versus 28 diagnostics pi_control 36 20-year run Initialized same way as 28 (spunup ocean) Could be extended to 50 years All diags are on the CESM1.5 webpage at: http://www.cesm.ucar.edu/working_groups/Atmosphere/development/cesm1_5/

36 versus 28 diagnostics 36 decently balanced: RESTOM =-0.08 W/m2 For the same period: for 28, RESTOM = 0.03W/m2 36 is warmer than 28 Impact on sea-ice ? Sea-ice already was too low in 28)

36 versus 28 (AMWG diags) Surface Temperature (TS) TS is warmer in 36. Global: ΔTS = 0.23K Ocean: ΔTS = 0.15K Land: ΔTS = 0.46K TS is warmer in 36. Largest differences are over land

36 versus 28 (AMWG diags) Precipitable water 28: PREH20 = 21.37 mm 36: PREH20 = 21.65 mm ΔPREH20 = 0.23 mm 36 is moister than 28 Consistent with 36 warmer than 28

Energy conservation issue (slide from Feb 9) Something happened between panel 1 and 2 Something happened with new autoconversion Pete’s fix for energy conservation

Energy conservation: RESTOM-RESSURF Abs( RESTOM – RESSURF) RESTOM - RESSURF is improved in 36 but not as much as when using new autoconversion

36 versus 28 (land diags) http://webext.cgd.ucar.edu/B1850/b.e15.B1850.f09_g16.pi_control.36/lnd/ From Keith Oleson: it seems to be a bit different in 36 from the land perspective, warmer overall. We anticipated the climate to be different because of changes to the nitrogen cycle (including methane) that are in the tag you are using.

36 versus 28 (ice diags) http://webext.cgd.ucar.edu/B1850/b.e15.B1850.f09_g16.pi_control.36/ice/ From Dave B: These are different and with only 20 years it is hard to say, but overall they appear to be within the variability.

36 versus 28 (ocean diags) From http://webext.cgd.ucar.edu/B1850/b.e15.B1850.f09_g16.pi_control.36/ocn/ http://webext.cgd.ucar.edu/B1850/b.e15.B1850G.f09_g16.pi_control.28/ocn/ RUNOFF HBLT From

Instructions to run cesm1.5 Tag for 28 (mini-breck code) Tag https://svn-ccsm-models.cgd.ucar.edu/cesm1/exp/branch_tags/cesm1_5_beta03_cntlexp_tags/cesm1_5_beta03_cntlexp06 + use modifications in (you REALLY need these !!!!) http://www.cesm.ucar.edu/working_groups/Atmosphere/development/instructions/ Tag for 36 (modern version of the code) Tag: https://svn-ccsm-models.cgd.ucar.edu/cesm1/exp/branch_tags/cesm1_5_alpha06_cntlexp_tags/cesm1_5_alpha06_cntlexp07 Create new case command ./create_newcase -case $yourcasename -compset B1850 -res f09_g16 -mach yellowstone -user_mods_dir b1850 -pecount X -project $project_number This only works for B1850. For other compsets (F), use modifications in : http://www.cesm.ucar.edu/working_groups/Atmosphere/development/instructions/

Instructions to run cesm1.5 Living document http://www.cesm.ucar.edu/working_groups/Atmosphere/development/instructions As of today (March 9, 2016) B1850 out of the box