TITLE

Impact of a New Radiation Package, McRad, in the ECMWF Integrated Forecasting System

AUTHOR(S)
Morcrette, J.-J.; Barker, H. W.; Cole, J. N. S.; Iacono, M. J.; Pincus, R.
PUB. DATE
December 2008
SOURCE
Monthly Weather Review;Dec2008, Vol. 136 Issue 12, p4773
SOURCE TYPE
Academic Journal
DOC. TYPE
Article
ABSTRACT
A new radiation package, “McRad,” has become operational with cycle 32R2 of the Integrated Forecasting System (IFS) of the European Centre for Medium-Range Weather Forecasts (ECMWF). McRad includes an improved description of the land surface albedo from Moderate Resolution Imaging Spectroradiometer (MODIS) observations, the Monte Carlo independent column approximation treatment of the radiative transfer in clouds, and the Rapid Radiative Transfer Model shortwave scheme. The impact of McRad on year-long simulations at TL159L91 and higher-resolution 10-day forecasts is then documented. McRad is shown to benefit the representation of most parameters over both shorter and longer time scales, relative to the previous operational version of the radiative transfer schemes. At all resolutions, McRad improves the representation of the cloud–radiation interactions, particularly in the tropical regions, with improved temperature and wind objective scores through a reduction of some systematic errors in the position of tropical convection as a result of a change in the overall distribution of diabatic heating over the vertical plane, inducing a geographical redistribution of the centers of convection. Although smaller, the improvement is also seen in the rmse of geopotential in the Northern and Southern Hemispheres and over Europe. Given the importance of cloudiness in modulating the radiative fluxes, the sensitivity of the model to cloud overlap assumption (COA) is also addressed, with emphasis on the flexibility that is inherent to this new RT approach when dealing with COA. The sensitivity of the forecasts to the space interpolation that is required to efficiently address the high computational cost of the RT parameterization is also revisited. A reduction of the radiation grid for the Ensemble Prediction System is shown to be of little impact on the scores while reducing the computational cost of the radiation computations. McRad is also shown to decrease the cold bias in ocean surface temperature in climate integrations with a coupled ocean system.
ACCESSION #
36092260

 

Related Articles

  • 3-D radiative transfer in large-eddy simulations - experiences coupling the TenStream solver to the UCLA-LES. Jakub, F.; Mayer, B. // Geoscientific Model Development Discussions;2015, Vol. 8 Issue 10, p9021 

    The recently developed three-dimensional TenStream radiative transfer solver was integrated into the UCLA-LES cloud resolving model. This work documents the overall performance of the TenStream solver as well as the technical challenges migrating from 1-D schemes to 3-D schemes. In particular...

  • Reduction of radiation biases by incorporating the missing cloud variability via downscaling techniques: a study using the 3-D MoCaRT model. Gimeno^Garc´ýa, S.; Trautmann, T.; Venema, V. // Atmospheric Measurement Techniques Discussions;2012, Vol. 5 Issue 1, p1543 

    The article presents a study which applies the three-dimensional (3-D) Monte Carlo Radiative Transfer (MoCaRT) model in an effort to describe effects of cloud heterogeneity on radiances and broadband flux densities. The study performs 3-D radiative transfer simulations of nadir reflected...

  • Radiative Heat Transfer Computations as a Free Molecular Flow Modeling Tool. Gochberg, Lawrence A.; Balakrishna, Ajit // AIP Conference Proceedings;2005, Vol. 762 Issue 1, p306 

    The use of an analogy between radiative heat transfer and free molecular flow is one that is straightforward, but apparently not often used in practice, nor is it often cited in the literature. The purpose of this article is to make this concept more familiar to technical audiences who might...

  • Efficient Monte Carlo Methods for Radiative Transfer Modeling. Iwabuchi, Hironobu // Journal of the Atmospheric Sciences;Sep2006, Vol. 63 Issue 9, p2324 

    Demands for Monte Carlo radiative transfer modeling have grown with the increase in computational power in recent decades. This method provides realistic simulations of radiation processes for various types of application, including radiation budgets in cloudy conditions and remote measurements...

  • Reabsorption of laser-induced fluorescence in a plant canopy: Stochastic model. Krekov, G. M.; Krekova, M. M.; Lisenko, A. A.; Matvienko, G. G. // Optics & Spectroscopy;Apr2009, Vol. 106 Issue 4, p514 

    This paper continues the series of publications on the statistical simulation of transspectral processes. A system of interrelated radiative transfer equations is proposed. This system gives a formal basis for a numerical analysis of a wider range of spectroscopic effects that accompanies the...

  • Multidimensional Longwave Forcing of Boundary Layer Cloud Systems. Mechem, David B.; Kogan, Yefim L.; Ovtchinnikov, Mikhail; Davis, Anthony B.; Evans, K. Franklin; Ellingson, Robert G. // Journal of the Atmospheric Sciences;Dec2008, Vol. 65 Issue 12, p3963 

    The importance of multidimensional (MD) longwave radiative effects on cloud dynamics is evaluated in an eddy-resolving model (ERM)—the two-dimensional analog to large-eddy simulation (LES)—framework employing multidimensional radiative transfer [Spherical Harmonics Discrete...

  • Detecting Dependence in the Sensitive Parameter Space of a Model Using Statistical Inference and Large Forecast Ensembles. McLay, J. G.; Liu, M. // Monthly Weather Review;Oct2014, Vol. 142 Issue 10, p3734 

    This study looks for evidence of correlation among model physical parameters in the sensitive parameter space defined by those randomly sampled physical parameter vectors that induce the most notable response in some forecast metric. These 'sensitive parameter vectors' are identified through an...

  • Dynamics of a Polymer Chain in a Melt. Hagita, Katsumi; Takano, Hiroshi // AIP Conference Proceedings;2003, Vol. 690 Issue 1, p382 

    The dynamics of a polymer chain in a melt is discussed on the basis of the results of recent Monte Carlo simulations. © 2003 American Institute of Physics

  • Long time scale kinetic Monte Carlo simulations without lattice approximation and predefined event table. Henkelman, Graeme; Jo´nsson, Hannes // Journal of Chemical Physics;12/1/2001, Vol. 115 Issue 21, p9657 

    We present a method for carrying out long time scale dynamics simulations within the harmonic transition state theory approximation. For each state of the system, characterized by a local minimum on the potential energy surface, multiple searches for saddle points are carried out using random...

Share

Read the Article

Courtesy of THE LIBRARY OF VIRGINIA

Sorry, but this item is not currently available from your library.

Try another library?
Sign out of this library

Other Topics