Search Results

You are looking at 1 - 10 of 28 items for :

  • CCSM4/CESM1 x
  • All content x
Clear All
Laura Landrum, Bette L. Otto-Bliesner, Eugene R. Wahl, Andrew Conley, Peter J. Lawrence, Nan Rosenbloom, and Haiyan Teng

European summer temperature anomalies ( Büntgen and Tegel 2011 ) that likely track the trajectory of annual temperature as well ( Cook et al. 2004a ). MacDonald and Case (2005) find a prolonged period of negative-phase Pacific decadal oscillation (PDO) during the MCA that is contemporaneous with a severe megadrought in the western United States. A combination of data reconstruction and modeling work suggests that modal behavior can be forced from one phase of a mode to another for several years to as

Full access
Keith Oleson

air temperature), and change in the heat island (ΔHI; 2080–99 RCP8.5 U − R minus 1986–2005 U − R air temperature) (°C). Region boundaries (defined as in McCarthy et al. 2010a ) are illustrated in Fig. 5 : Western North America (WNA), Central America (CAm), South America (SAm), Eastern North America (ENA), Europe (EU), Western Africa (WAf), Middle East (ME), Eastern Africa (EAf), Central Asia (CAs), Eastern Asia (EAs), Australia/New Zealand (ANZ). Fig . 5. The 2080–99 minus 1986

Full access
Peter J. Lawrence, Johannes J. Feddema, Gordon B. Bonan, Gerald A. Meehl, Brian C. O’Neill, Keith W. Oleson, Samuel Levis, David M. Lawrence, Erik Kluzek, Keith Lindsay, and Peter E. Thornton

use any natural vegetation grown in an area (e.g., pastoral herding practices as used in Africa or Mongolia, or rangeland grazing in Australia). The historical CMIP5 time series suggests that the pasture land unit applies to both of these definitions, as there are very intensive pasture values in very sparsely vegetated parts of the world that cannot be considered equivalent to the intensive grazing of the lush pastoral grass fields of Europe or North America. To address these definitional

Full access
Jenny Lindvall, Gunilla Svensson, and Cecile Hannay

Europe or North America, whereas tropical, Arctic, and arid sites are more scarce and consequently such sites that fulfill our requirements have been harder to find. In total, 35 micrometeorological flux tower sites provide the observational data used in this study. All sites included in the study have at least 2 yr and up to 16 yr of eddy-correlation measurements. Table 1. Flux sites used in this study. The altitude is in meters above mean sea level at which the flux site is located. Hgt is the

Full access
Richard B. Neale, Jadwiga Richter, Sungsu Park, Peter H. Lauritzen, Stephen J. Vavrus, Philip J. Rasch, and Minghua Zhang

multicentennial spinup period when subject to preindustrial (circa 1850) major climate forcings. b. Observational data Comparisons are made to standard observational satellite, in situ and reanalysis datasets including the 15-yr European Center for Medium-Range Weather Forecasts (ECMWF) Re-Analysis (ERA-15; Gibson et al. 1997 ), 40-yr ECMWF Re-Analysis (ERA-40; Uppala et al. 2005 ), ECMWF Interim Re-Analysis (ERA-Interim; Dee et al. 2011 ), the NASA Modern-Era Retrospective Analysis for Research and

Full access
Samuel Levis, Gordon B. Bonan, Erik Kluzek, Peter E. Thornton, Andrew Jones, William J. Sacks, and Christopher J. Kucharik

last 10 years) against the observed for years 1991–2000. 3. Results CROP simulates the annual cycle of leaf area index (LAI) for the three managed crops more realistically than for the unmanaged crop plant functional type (pft). In four sample regions (Europe, central Russia, Argentina, and Midwestern North America) the managed crops show reduced winter LAI and clear spring planting and fall harvest periods. At the height of the growing season, the managed crops display higher LAI. In contrast, the

Full access
David M. Lawrence, Keith W. Oleson, Mark G. Flanner, Christopher G. Fletcher, Peter J. Lawrence, Samuel Levis, Sean C. Swenson, and Gordon B. Bonan

CCSM3. CCSM4 shows improvements in the annual cycle of T air for Alaska and India. Over Europe the CCSM4 simulation is slightly worse. Elsewhere, the differences between the two models are difficult to distinguish or contain seasons that are better and others that are worse. Summary bias and centered root-mean-square error (RMSE) statistics for global land (excluding Antarctica) T air are listed in Table 1 . Based on the global land T air statistics, CCSM4 is a marginally better model with a

Full access
C. Kendra Gotangco Castillo, Samuel Levis, and Peter Thornton

MODIS dataset. Differences between the last 30 yr of the fully coupled CCSM4CNDV (see supplemental material http://dx.doi.org/10.1175/JCLI-D-11-00372.s2 Fig. S2.1 ) and the offline CNDV simulations are minimal because the former generated the atmospheric data prescribed in the latter. In CCSM4CNDV, there are slightly more needleleaf evergreens in North America. Deciduous trees cover more of the northeastern United States, Europe, and northeastern Asia compared to CNDV. There is slightly more

Full access
David M. Lawrence, Andrew G. Slater, and Sean C. Swenson

of fractional soil ice content for an illustrative grid cell in northern European Russia ( Fig. 7 ). The depth of seasonal soil thaw, that is, the active layer, varies from year to year in step with interannual climate variations, but it does not exhibit a clear deepening trend until around 1985 (only 1970 onward is shown). In the year 2008, a talik forms that lasts for a few years, before a sequence of relatively cool summers along with low snow depths in the early to mid-2010s temporarily

Full access
Kevin Raeder, Jeffrey L. Anderson, Nancy Collins, Timothy J. Hoar, Jennifer E. Kay, Peter H. Lauritzen, and Robert Pincus

CAM4-FV: one with the model running at nominal 1° resolution from analyses provided by the European Centre for Medium-Range Weather Forecasts (interpolated from the original T799 resolution; roughly ¼° resolution) and another from an ensemble reanalysis (described in section 5a ) using DART and a 2° version of the model. The evaluation is performed in observation space (see section 4a ) against radiosonde temperature observations that fell within three standard deviations of the DART

Full access