The basic principle is that we should strive to include all relevant transient forcings over this period if the functionality exists in the model, noting that conformability with the CMIP5 controls and 20th Century transient is crucial.
G. A. Schmidt, J. H. Jungclaus, C. M. Ammann, E. Bard, P. Braconnot, T. J. Crowley, G. Delaygue, F. Joos, N. A. Krivova, R. Muscheler, B. L. Otto-Bliesner, J. Pongratz, D. T. Shindell, S. K. Solanki, F. Steinhilber, and L. E. A. Vieira
|Orbital parameters|| Annually varying|
Table provided (0-2100 CE/AD), if not internally calculated
|Date of vernal equinox||March 21 at Noon|
|Trace gases||Annually varying (850-1850) (Table provided)|
|Volcanic Aerosols||Multiple reconstructions (of AOD, Effective Radius, Mass)|
|Solar irradiance||choose at least one between Multiple reconstructions provided below|
|Ozone||solar related variations (parameterised as function of change in solar irradiance - Drew Shindell)||same as in CMIP5 PI|
|Aerosols||biomass burning changes????||same as in CMIP5 PI|
|Vegetation|| Land cover change (natural vegetation to crop/C3 pasture/C4 pasture)|
(Pongratz et al., 2008; Ramankutty and Foley, 1999)
|same as in CMIP5 PI|
|Ice sheets||No changes from Pre-Ind control|
|Topography and coastlines||same as in CMIP5 PI|
Multiple reconstructions of annual total solar irradiance are provided. These are designed to either fit smoothly with the reconstructions used in the post-1850 CMIP5 simulations (Wang, Lean and Sheely (2005)), or to explore independent estimates of the long term solar trends. Each series has an 11 year solar cycle throughout the time series (synthetic for pre-1610, based on a relationship between cycle magnitude and long-term TSI) and comes with an estimate of the spectral changes (as a function of the TSI anomaly). Each reconstruction is calibrated to the WLS modern values. See the README.txt file for details of filenames and formats.
Spectral reconstruction based on a flux transport model of the open and closed flux using the observed sunspot record as the main input. This comes in two versions, A) a “no-background” version that just has TSI variations similar to that seen over a solar cycle today, and B) a “with background” version with longer term trends in the solar minimum.
Wang, Y.-M., J. L. Lean, and N. R. Sheeley, Jr. (2005), Modeling the Sun’s Magnetic Field and Irradiance since 1713, ApJ, 625, 522–538, doi:10.1086/429689.
Reconstruction based on an Antarctica stack of 10Be records scaled linearly to the modern-to-Maunder Minimum TSI in the two WLS reconstructions.
Delaygue, G and E. Bard, (2009), Solar forcing based on Be-10 in Antarctica ice over the past millennium and beyond, EGU 2009 General Assembly, #EGU2009-6943
Reconstruction based on the 14C record scaled based on an inverse regression to the two WLS reconstructions.
Muscheler, R., F. Joos, J. Beer, S.A. Müller, M. Vonmoos, and I. Snowball (2007), Solar activity during the last 1000 yr inferred from radionuclide records Quaternary Science Reviews, Vol. 26, pp. 82-97. doi:10.1016/j.quascirev.2006.07.012
Reconstruction based on a model of the open and closed magnetic flux including an estimate of the 11 yr cycle. We recommend patching this into the WLS w/background values in 1850.
N.A. Krivova, L. Balmaceda and S.K. Solanki, (2007), Reconstruction of solar total irradiance since 1700 from the surface magnetic flux. Astronomy and Astrophysics, 467, 335-346.http://www.mps.mpg.de/homes/natalie/PAPERS/aa6725-06.pdf
Reconstruction based on a Greenland 10Be core and a different model of solar flux. 11yr cycle is synthetic. We recommend patching this into the WLS w/background values in 1850.
Steinhilber, F., J. Beer, and C. Frohlich (2009), Total solar irradiance during the Holocene, Geophys. Res. Lett., 36, L19704, doi:10.1029/2009GL040142.
A parameterisation of ozone changes in the atmosphere (lat, lon, altitude) as a function of changing solar irradiance (including spectral variations) is available based on the results of Shindell et al (2006). Data file: dO3_shindell, data description: ozone-feedback.txt.
Shindell, D.T., G. Faluvegi, R.L. Miller, G.A. Schmidt, J.E. Hansen, and S. Sun, 2006: Solar and anthropogenic forcing of tropical hydrology. Geophys. Res. Lett., 33, L24706, doi:10.1029/2006GL027468,2006. http://pubs.giss.nasa.gov/docs/2006/2006_Shindell_etal_4.pdf
Two alternative data sets are provided below. It is up to the groups to choose the Gao-Robock-Amann or the Crowley reconstruction for their last millenium simulation.
Time series of global hemispheric total stratospheric sulphate injections from volcanic eruptions for the past 1500 years as well as estimates of stratospheric loading as a function of latitude, altitude, and month are available from IVI2link
The data are derived from 54 ice core records, 32 from the Arctic, and 22 from Antarctica. It is based on the most comprehensive set of ice cores, an updated extraction record, updated ice core deposition to global stratospheric aerosol loading conversion factors, and an advanced spatial-temporal transport parameterization scheme (Gao et al., 2008)
The stratospheric aerosol loadings (in units of Tg) provided in the IVI2 data set may be converted into aerosol optical depth (AOD) by dividing the loadings by 150 Tg (Stothers, 1984). The AOD time series can then be used to calculate the corresponding radiative forcing (in units of Wm-2) by multiplying it by (-20) (Wigley et al., 2005). The conversion to AOD is valid for aerosols with effective radius in the visible spectral range.
IVI2TotalLoading501-2000.txt dataset file has a misleading name and gives the Total Injection, not Loading.
Gao, C., A. Robock, and C. Ammann: Volcanic forcing of climate over the last 1500 years: An improved ice-core based index for climate models. J. Geophys. Res., 113, D2311, doi:10.1029/2008JD010239 (2008).
Stothers, R.B., The great Tambora eruptions in 1815 and its aftermath. Science, 224(4654), 1191-1198 (1984). Wigley, T.M.L., C.M. Ammann, B.D. santer, and S.C.B. Raper: Effect of climate sensitivity on the response of volcanic forcing. J. Geophys. Res., 110,D09107, doi:10.1029/2004JD005557
The volcanic forcing is calculated using time series of aerosol optical depth (AOD) at 0.55μm and of the effective radius (Reff) (Crowley et al., 2008). The time resolution of the series is ten days and the data are provided at four equal area latitude bands.
AOD estimates are based on a correlation between sulphate in Antarctic ice cores and satellite data (Sato et al., 1993).
Reff growth and decay is based on satellite observations of the Pinatubo eruption in 1991, with eruptions larger than that of Pinatubo (maximum is 0.15) being scaled by the theoretical calculations for very large eruptions (Pinto et al., 1989). In the model AOD is distributed between 20-86 hPa over three vertical levels, with a maximum at 50 hPa.
Sensitivity experiments for the model response to the Pinatubo eruption yield an average global temperature change (0.4 K) comparable to observations. For the largest eruption of the last millennium, the 1258 AD eruption, a NH summer temperature anomaly over land of 1.2 K is found in agreement with reconstructions (Timmreck et al., 2009)
The dataset is available in a zip file.
Crowley, T. et al. Volcanism and the Little Ice Age. PAGES Newsletter, 16, 22-23 (2008).
Sato, M., Hansen, J.E., McCormick, M.P. & Pollack, J.B. Stratospheric aerosol optical depths, 1850-1990. J. Geophys. Res., 98(D12), 22,987-22,994, doi:10.1029/93JD02553 (1993).
Pinto, J.P., Turco, R.P., & Toon, O.B. Self-limiting physical and chemical effects in volcanic eruption clouds. J. Geophys. Res., 94(D8), 11,165-11,174, doi:10.1029/JD094iD08p11165 (1989).
Timmreck, C. et al. Limited temperature response to the very large AD 1258 volcanic eruption. Geophys. Res. Lett., 36, L21708, doi:10.1029/2009GL040083 (2009).
The following orbital parameters parameters should be used, if they are not internally calculated.
Note: calculation from Berger (1978), annually varying.
Over the period 0-2100 CE, the parameters are well approximated by the following linear regressions:
|ECC||0.017475 - 0.000000382 * Year|
|OBL||23.697 - 0.000128 * Year|
|PERI-180||68.79 + 0.0170 * Year|
Anthropogenic land cover change is considered by applying a reconstruction of global agricultural areas and land cover. The recommended scenarios are Pongratz2008 (Pongratz et al., 2008) and/or KK10 (Kaplan et al. 2011)
Global maps with a spatial resolution of 0.5° and an annual timescale contain 14 vegetation types and discriminate between the agricultural categories cropland, and C3 and C4 pastures. The reconstruction merges published maps of agriculture from AD1700 to 1992 and a population-based approach to quantify agriculture from AD 800 to 1700.
The data set can be obtained from the World Data Center for Climate (doi:10.1594/WDCC/RECON_LAND_COVER_800-1992), along with two alternate maximum and minimum reconstructions that can be used to test the structural uncertainty.
Pongratz, J., Reick, C.H., Raddatz, T. & Claussen, M. A reconstruction of global agricultural areas and land cover for the last millennium. Global Biogeochem. Cycles, 22, GB3018, doi:10.1029/2007GB003153 (2008).
To access the files, click here RECON_LAND_COVER_800-1992
The following alternative anthropogenic land use forcing data set has been provided by Jed Kaplan
Kaplan, J. O., Krumhardt, K. M., Ellis, E. C., Ruddiman, W. F., Lemmen, C. and Goldewijk, K. K. 2010. Holocene carbon emissions as a result of anthropogenic land cover change. The Holocene, 21(5), 775-791, doi:10.1177/0959683610386983.
|Initial conditions||Branch off PI after adjustment||Same as in PI|
|Model spin up||Same as in PI|