Author: Xin Zhou Publisher: ISBN: Category : Languages : en Pages : 234
Book Description
This study evaluates the performance of 20 climate models participating in the second phase of the Atmospheric Model Intercomparison Project (AMIP II) in relation to surface heat flux over tropical oceans. We compare the AMIP II surface heat flux with that from the Objectively Analyzed Air-Sea Fluxes (OAFlux) and in situ buoys. The buoy data were taken from 66 Tropical Atmosphere Ocean (TAO) buoys in the Pacific, 18 Prediction and Research Moored Array (PlRATA) buoys in the Atlantic and 10 Research Moored Array (RAMA) buoys in the Indian Ocean. The annual mean ensemble values of short wave (Qsw), long wave (QLW), latent heat (QLH) and sensible heat (QSH) from models (OAFlux) are 217 (222), 59 (53), 121 (117) and 17 (9) W/m2 (all are absolute values) over the tropical oceans (300°S~30°N). Most models are able to simulate the spatial variability well, although there are some important differences among models. Most models overestimate in oceans away from the equator (especially northern and southern Pacific Oceans and southern Indian Ocean) for turbulent fluxes and in oceans near the equator for radiation fluxes. The multi-model ensemble, in general, simulates better than the individual models. The errors in turbulent heat flux seem to come mainly from the errors in surface wind speed and errors in radiative flux come from errors in cloud cover. Models with higher horizontal resolutions perform better than those with coarse resolutions. However, the dependence of our results on vertical resolution was not clear. The models (ACCESS 1-0, GFDL-HIRAM-C360, IPSL-CM5B-LR, MRI-AGCM3-2S) that performed better than other models are therefore recommended for the estimation of surface heat flux for further research.
Author: T. J. Phillips Publisher: ISBN: Category : Languages : en Pages : 28
Book Description
This report summarizes initial findings of a large-scale validation of the land-surface simulations of ten atmospheric general circulation models that are entries in phase II of the Atmospheric Model Intercomparison Project (AMIP II). This validation is conducted by AMIP Diagnostic Subproject 12 on Land-surface Processes and Parameterizations, which is focusing on putative relationships between the continental climate simulations and the associated models' land-surface schemes. The selected models typify the diversity of representations of land-surface climate that are currently implemented by the global modeling community. The current dearth of global-scale terrestrial observations makes exacting validation of AMIP II continental simulations impractical. Thus, selected land-surface processes of the models are compared with several alternative validation data sets, which include merged in-situ/satellite products, climate reanalyses, and off-line simulations of land-surface schemes that are driven by observed forcings. The aggregated spatio-temporal differences between each simulated process and a chosen reference data set then are quantified by means of root-mean-square error statistics; the differences among alternative validation data sets are similarly quantified as an estimate of the current observational uncertainty in the selected land-surface process. Examples of these metrics are displayed for land-surface air temperature, precipitation, and the latent and sensible heat fluxes. It is found that the simulations of surface air temperature, when aggregated over all land and seasons, agree most closely with the chosen reference data, while the simulations of precipitation agree least. In the latter case, there also is considerable inter-model scatter in the error statistics, with the reanalyses estimates of precipitation resembling the AMIP II simulations more than to the chosen reference data. In aggregate, the simulations of land-surface latent and sensible heat fluxes appear to occupy intermediate positions between these extremes, but the existing large observational uncertainties in these processes make this a provisional assessment. In all selected processes as well, the error statistics are found to be sensitive to season and latitude sector, confirming the need for finer-scale analyses which also are in progress.
Author: Publisher: ISBN: Category : Languages : en Pages : 8
Book Description
The Atmospheric Model Intercomparison Project has provided a unique opportunity to evaluate atmospheric general circulation model (AGCM) simulations made with realistic boundary forcing. Here we report on some results from AMIP Subproject No. 5, making use of a suite of observationally-based estimates of ocean surface heat fluxes to evaluate the seasonal cycle of surface heating as simulated by AGCMs.
Author: Publisher: ISBN: Category : Aeronautics Languages : en Pages : 602
Book Description
Lists citations with abstracts for aerospace related reports obtained from world wide sources and announces documents that have recently been entered into the NASA Scientific and Technical Information Database.
Author: Intergovernmental Panel on Climate Change Publisher: Cambridge University Press ISBN: 0521705967 Category : Business & Economics Languages : en Pages : 48
Book Description
The Climate Change 2007 volumes of the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC) provide the most comprehensive and balanced assessment of climate change available. This IPCC Working Group I report brings us completely up-to-date on the full range of scientific aspects of climate change. Written by the world's leading experts, the IPCC volumes will again prove to be invaluable for researchers, students, and policymakers, and will form the standard reference works for policy decisions for government and industry worldwide.
Author: Tianjun Zhou Publisher: Springer Science & Business Media ISBN: 3642418015 Category : Science Languages : en Pages : 468
Book Description
Coupled climate system models are of central importance for climate studies. A new model known as FGOALS ( the Flexible Global Ocean-Atmosphere-Land System model), has been developed by the Sate Key Laboratory of Numerical Modeling for Atmospheric Sciences and Geophysical Fluid Dynamics, Institute of Atmospheric Physics, Chinese Academy of Sciences (LASG/IAP, CAS), a first-tier national geophysical laboratory. It serves as a powerful tool, both for deepening our understanding of fundamental mechanisms of the climate system and for making decadal prediction and scenario projections of future climate change. "Flexible Global Ocean-Atmosphere-Land System Model: A Modeling Tool for the Climate Change Research Community” is the first book to offer systematic evaluations of this model’s performance. It is comprehensive in scope, covering both developmental and application-oriented aspects of this climate system model. It also provides an outlook of future development of FGOALS and offers an overview of how to employ the model. It represents a valuable reference work for researchers and professionals working within the related areas of climate variability and change. Prof. Tianjun Zhou, Yongqiang Yu, Yimin Liu and Bin Wang work at LASG, the Institute of Atmospheric Physics, Chinese Academy of Sciences, China.
Author: Xin Zhou
Author: T. J. Phillips
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Author: Intergovernmental Panel on Climate Change
Author: Glenn Hazen White
Author: Intergovernmental Panel on Climate Change
Author: E. Arbtin
Author: Tianjun Zhou