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--- pmip3:design:lm:index [2009/08/04 14:52] – Added link from GHG table line to GHG table data jypeter
+++ pmip3:design:lm:index [2009/09/12 01:33] – gavin
@@ Line 16: / Line 16: @@
 ^      ^   PMIP3  ^  Alternative solution  ^
-|  Orbital parameters  |  Annually varying (850-1850) (Table provided if not internally calculated)  |  1850 values or same as Pre-Ind CMIP5 control [ **ecc** =  ] - [ **obl** = ° ] - [ **peri-180°** = ° ]  |
+|  Orbital parameters  |  Annually varying (Table provided (for years 0-2100 CE/AD) if not internally calculated)   |  1850 values [ **ecc** = 0.01676 ] - [ **obl** = 23.459° ] - [ **peri-180°** = 280.32687° ] or same as Pre-Ind CMIP5 control |
 |  Date of vernal equinox  |  Mar 21 hr 0  |  same as CMIP5 control |
 |  Trace gases  |  Annually varying (850-1850) ([[index#reconstructed_evolution_of_trace_gases|Table provided]])  |  constant at CMIP5 control levels  [ **CO<sub>2</sub>** =  ppm ] - [ **CH<sub>4</sub>** =  ppb ] - [ **N<sub>2</sub>O** =  ppb ] - [ **CFC** =  ] - [ **O<sub>3</sub>** =  ]  |
@@ Line 58: / Line 58: @@
 The evolution of CO<sub>2</sub>, CH<sub>2</sub>, N<sub>2</sub>O over past 2 millennia {{:pmip3:design:lm:ghg_lawdome_giss_merge_c5mip_24jul09.1-2000.txt|table}} has been provided by [[joos@climate.unibe.ch|Fortunat Joos]] (University of Bern). Methods and references are provided in the downloadable file.
+==== Orbital forcing ====
+Calculation from Berger (1978), annually varying.
+Note that over the period 0-2100 CE, the parameters are well approximated by linear regressions
+ECC = 0.017475 - 0.000000382*Year
+OBL = 23.697   - 0.000128*Year
+PERI= 248.79   + 0.0170*Year
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