noaa-model-20990 Mesoproterozoic Global Climate Model Simulations Fiorella, R.P.; Sheldon, N.D. Mesoproterozoic Global Climate Model Simulations 2017-01-09 NCDC-Paleoclimatology ONLINE Files Pending https://www.ncdc.noaa.gov/paleo/study/20990 Investigator R.P. Fiorella Investigator N.D. Sheldon earth science paleoclimate paleoclimatic modeling minimum surface temperature,null,null,kelvin,annual,paleoclimatic modeling,null,null,N,Minimum surface temperature over output period earth science paleoclimate paleoclimatic modeling latitude,null,null,degree north,null,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling cloud ice mixing ratio,null,null,kilogram per kilogram,annual,paleoclimatic modeling,null,null,N,CLDICE earth science paleoclimate paleoclimatic modeling cloud cover,null,null,fraction,annual,paleoclimatic modeling,null,null,N,CLDLOW; Vertically-integrated low cloud earth science paleoclimate paleoclimatic modeling longwave cloud radiative effect,null,null,watt per square meter,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling convective precipitation,null,null,meter per second,annual,paleoclimatic modeling,null,null,N,liquid plus ice earth science paleoclimate paleoclimatic modeling large-scale precipitation,null,null,meter per second,annual,paleoclimatic modeling,null,null,N,liquid plus ice earth science paleoclimate paleoclimatic modeling snow depth,null,null,meter,annual,paleoclimatic modeling,null,null,N,snow depth over ice earth science paleoclimate paleoclimatic modeling cloud condensed water content,null,null,gram per square meter,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling cloud liquid water content,null,null,gram per square meter,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling precipitable water,null,null,kilogram per square meter,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling cloud cover,null,null,fraction,annual,paleoclimatic modeling,null,null,N,CLOUD; total cloud cover earth science paleoclimate paleoclimatic modeling temperature tendency,null,null,kelvin per second,annual,paleoclimatic modeling,null,null,N,DTCOND; due to moist processes earth science paleoclimate paleoclimatic modeling surface downwelling longwave radiation,null,null,watt per square meter,annual,paleoclimatic modeling,null,null,N,FLDS earth science paleoclimate paleoclimatic modeling surface downwelling shortwave radiation,null,null,watt per square meter,annual,paleoclimatic modeling,null,null,N,FSDS earth science paleoclimate paleoclimatic modeling cloud liquid water mixing ratio,null,null,kilogram per kilogram,annual,paleoclimatic modeling,null,null,N,Prognostic in-cloud water mixing ratio earth science paleoclimate paleoclimatic modeling surface type,null,null,fraction,annual,paleoclimatic modeling,null,null,N,Fraction of sfc area covered by land earth science paleoclimate paleoclimatic modeling relative humidity,null,null,percent,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling maximum surface temperature,null,null,kelvin,annual,paleoclimatic modeling,null,null,N,Maximum surface temperature over output period earth science paleoclimate paleoclimatic modeling eastward wind speed,null,null,meter per second,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling surface net upward clear-sky longwave radiation,null,null,watt per square meter,annual,paleoclimatic modeling,null,null,N,FLNSC earth science paleoclimate paleoclimatic modeling surface net downward shortwave radiation,null,null,watt per square meter,annual,paleoclimatic modeling,null,null,N,FSNS earth science paleoclimate paleoclimatic modeling top-of-atmosphere net downward clear-sky shortwave radiation,null,null,watt per square meter,annual,paleoclimatic modeling,null,null,N,FSNTC; top of model earth science paleoclimate paleoclimatic modeling latent heat flux,null,null,watt per square meter,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling specific humidity,null,null,kilogram per kilogram,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling temperature tendency,null,null,kelvin per second,annual,paleoclimatic modeling,null,null,N,due to shortwave heating earth science paleoclimate paleoclimatic modeling snow water equivalent,null,null,meter,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling shortwave cloud radiative effect,null,null,watt per square meter,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling surface downward x stress,null,null,pascal,annual,paleoclimatic modeling,null,null,N,eastward wind stress earth science paleoclimate paleoclimatic modeling cloud ice content,null,null,gram per square meter,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling geopotential height,null,null,meter,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling cloud liquid water mixing ratio,null,null,kilogram per kilogram,annual,paleoclimatic modeling,null,null,N,CLDLIQ earth science paleoclimate paleoclimatic modeling cloud cover,null,null,fraction,annual,paleoclimatic modeling,null,null,N,CLDTOT; Vertically-integrated total cloud earth science paleoclimate paleoclimatic modeling cloud cover,null,null,fraction,annual,paleoclimatic modeling,null,null,N,CLDCON; convective cloud cover earth science paleoclimate paleoclimatic modeling surface downwelling clear-sky longwave radiation,null,null,watt per square meter,annual,paleoclimatic modeling,null,null,N,FLDSC earth science paleoclimate paleoclimatic modeling surface downwelling clear-sky shortwave radiation,null,null,watt per square meter,annual,paleoclimatic modeling,null,null,N,FSDSC earth science paleoclimate paleoclimatic modeling insolation,null,null,watt per square meter,annual,paleoclimatic modeling,null,null,N,FSDTOA earth science paleoclimate paleoclimatic modeling top-of-atmosphere net downward shortwave radiation,null,null,watt per square meter,annual,paleoclimatic modeling,null,null,N,FSNTOA; top of atmosphere earth science paleoclimate paleoclimatic modeling top-of-atmosphere outgoing shortwave radiation,null,null,watt per square meter,annual,paleoclimatic modeling,null,null,N,FSUTOA earth science paleoclimate paleoclimatic modeling vertical pressure velocity,null,null,pascal per second,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling insolation,null,null,watt per square meter,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling temperature,null,null,kelvin,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling surface downward y stress,null,null,pascal,annual,paleoclimatic modeling,null,null,N,northward wind stress earth science paleoclimate paleoclimatic modeling surface air temperature,null,null,kelvin,annual,paleoclimatic modeling,null,null,N,Reference height temperature earth science paleoclimate paleoclimatic modeling aerosol optical depth,null,null,dimensionless,annual,paleoclimatic modeling,null,null,N,Total Aerosol Optical Depth in visible band earth science paleoclimate paleoclimatic modeling top-of-atmosphere outgoing longwave radiation,null,null,watt per square meter,annual,paleoclimatic modeling,null,null,N,FLUT earth science paleoclimate paleoclimatic modeling sea ice cover,null,null,fraction,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling surface type,null,null,fraction,annual,paleoclimatic modeling,null,null,N,Fraction of sfc area covered by ocean earth science paleoclimate paleoclimatic modeling surface geopotential,null,null,square meter per square second,annual,paleoclimatic modeling,null,null,N,at surface earth science paleoclimate paleoclimatic modeling convective snowfall,null,null,meter per second,annual,paleoclimatic modeling,null,null,N,water equivalent earth science paleoclimate paleoclimatic modeling large-scale snowfall,null,null,meter per second,annual,paleoclimatic modeling,null,null,N,water equivalent earth science paleoclimate paleoclimatic modeling northward wind speed,null,null,meter per second,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling cloud cover,null,null,fraction,annual,paleoclimatic modeling,null,null,N,CLDHGH; Vertically-integrated high cloud earth science paleoclimate paleoclimatic modeling top-of-atmosphere net downward shortwave radiation,null,null,watt per square meter,annual,paleoclimatic modeling,null,null,N,FSNT; top of model earth science paleoclimate paleoclimatic modeling surface pressure,null,null,pascal,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling sea level pressure,null,null,pascal,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling sensible heat flux,null,null,watt per square meter,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling wind speed,null,null,meter per second,annual,paleoclimatic modeling,null,null,N,at 10 meters earth science paleoclimate paleoclimatic modeling cloud cover,null,null,fraction,annual,paleoclimatic modeling,null,null,N,CLDMED; Vertically-integrated mid-level cloud earth science paleoclimate paleoclimatic modeling cloud ice content,null,null,fraction,annual,paleoclimatic modeling,null,null,N,FICE; Fractional ice content within cloud earth science paleoclimate paleoclimatic modeling top-of-atmosphere net upward longwave radiation,null,null,watt per square meter,annual,paleoclimatic modeling,null,null,N,FLNT earth science paleoclimate paleoclimatic modeling cloud ice mixing ratio,null,null,kilogram per kilogram,annual,paleoclimatic modeling,null,null,N,Prognostic in-cloud ice mixing ratio earth science paleoclimate paleoclimatic modeling evaporation,null,null,kilogram per square meter per second,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling specific humidity,null,null,kilogram per kilogram,annual,paleoclimatic modeling,null,null,N,reference height earth science paleoclimate paleoclimatic modeling temperature tendency,null,null,kelvin per second,annual,paleoclimatic modeling,null,null,N,due to longwave heating earth science paleoclimate paleoclimatic modeling surface temperature,null,null,kelvin,annual,paleoclimatic modeling,null,null,N,Surface temperature (radiative) earth science paleoclimate paleoclimatic modeling northward ocean heat transport,null,null,kelvin meter per second,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling longitude,null,null,degree east,null,paleoclimatic modeling,null,null,N,null earth science paleoclimate paleoclimatic modeling surface net upward longwave radiation,null,null,watt per square meter,annual,paleoclimatic modeling,null,null,N,FLNS earth science paleoclimate paleoclimatic modeling top-of-atmosphere net upward clear-sky longwave radiation,null,null,watt per square meter,annual,paleoclimatic modeling,null,null,N,FLNTC earth science paleoclimate paleoclimatic modeling top-of-atmosphere outgoing clear-sky longwave radiation,null,null,watt per square meter,annual,paleoclimatic modeling,null,null,N,FLUTC earth science paleoclimate paleoclimatic modeling surface net downward clear-sky shortwave radiation,null,null,watt per square meter,annual,paleoclimatic modeling,null,null,N,FSNSC earth science paleoclimate paleoclimatic modeling top-of-atmosphere net downward clear-sky shortwave radiation,null,null,watt per square meter,annual,paleoclimatic modeling,null,null,N,FSNTOAC; top of atmosphere earth science paleoclimate paleoclimatic modeling atmospheric boundary layer thickness,null,null,meter,annual,paleoclimatic modeling,null,null,N,null earth science paleoclimate model atmosphere model geoscientificInformation 1600000000 cal yr BP 1000000000 cal yr BP Complete -90 90 -180 180 Geographic Region Global Global>LATITUDE >LONGITUDE None Please cite original publication, online resource, dataset and publication DOIs (where available), and date accessed when using downloaded data. 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Boulder CO 80305-3328 USA online ASCII Richard P. Fiorella and Nathan D. Sheldon 2017 Geology 10.1130/G38682.1

The Proterozoic Eon (2500-542 Ma) appears to have been a warm period bookended by glaciations, despite a 5%-18% reduction in solar output compared to modern during this interval. Radiative-convective climate models suggest that glaciation could have been avoided if pCO2 were 30-300x preindustrial atmospheric levels (PIAL, 280 ppmv). Constraints from late Mesoproterozoic (ca. 1.2-1.0 Ga) microfossil calcification sheaths and paleosol mass balance, however, suggest that pCO2 may have been no higher than 10x PIAL. In the lower oxygen Mesoproterozoic atmosphere, an increased CH4 flux from methanogenic bacteria may have contributed additional greenhouse warming. We use a fully coupled atmosphere-ocean general circulation model (the U.S. National Center for Atmospheric Research Community Earth System Model, CESM) to test whether these pCO2 constraints are consistent with the absence of widespread glaciation inferred from the geologic record. We vary pCO2 and pCH4 between 1400 and 2800 ppmv and 3.5 and 140 ppmv, respectively, using a reconstructed 1.0 Ga paleogeography and solar output reduced by 9%. Our simulations suggest that ice-free conditions can be maintained at 10x PIAL CO2 when CH4 is 140 ppmv. When CH4 is lowered to 28 ppmv at 10x PIAL CO2, or if pCO2 is lowered to 5x PIAL, permanent land snow cover at high and middle latitudes suggests that glaciation would be more extensive than preindustrial conditions, but with warm tropical regions. Global glaciation occurs if pCO2 is reduced below 5x PIAL. Overall, our simulations suggest that an ice-free climate for the Mesoproterozoic (1.6-1.0 Ga) is consistent with the relatively low pCO2 implied from proxies if CH4 or other greenhouse gas concentrations were sufficiently elevated. STUDY NOTES: Climate model simulations for the Mesoproterozoic (1.6-1.0 billion years ago) using the NCAR CESM1.2 model (modified for Mesoproterozoic conditions). Model runs for atmospheric CO2 at ~1, 5, and 10 times pre-industrial levels, (pCO2 between 1400 and 2800 ppmv) and for pCH4 varying between 3.5 and 140 ppmv. Simulations suggest ice-free conditions could be maintained for 2800ppmv CO2 if CH4 was elevated to 140ppmv.

GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/gcmoutput/fiorella2017/ Data Folder; Mesoproterozoic Model Simulations GET DATA https://www1.ncdc.noaa.gov/pub/data/paleo/gcmoutput/fiorella2017/readme-fiorella2017.txt Data Description; Mesoproterozoic Model Simulations Readme File USA/NOAA DIF Version 9.8.4 2018-12-11 2018-12-11