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  • Author or Editor: L. P. Graham x
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E. Raschke
,
J. Meywerk
,
K. Warrach
,
U. Andrea
,
S. Bergström
,
F. Beyrich
,
F. Bosveld
,
K. Bumke
,
C. Fortelius
,
L. P. Graham
,
S.-E. Gryning
,
S. Halldin
,
L. Hasse
,
M. Heikinheimo
,
H.-J. Isemer
,
D. Jacob
,
I. Jauja
,
K.-G. Karlsson
,
S. Keevallik
,
J. Koistinen
,
A. van Lammeren
,
U. Lass
,
J. Launianen
,
A. Lehmann
,
B. Liljebladh
,
M. Lobmeyr
,
W. Matthäus
,
T. Mengelkamp
,
D. B. Michelson
,
J. Napiórkowski
,
A. Omstedt
,
J. Piechura
,
B. Rockel
,
F. Rubel
,
E. Ruprecht
,
A.-S. Smedman
, and
A. Stigebrandt

The Baltic Sea Experiment (BALTEX) is one of the five continental-scale experiments of the Global Energy and Water Cycle Experiment (GEWEX). More than 50 research groups from 14 European countries are participating in this project to measure and model the energy and water cycle over the large drainage basin of the Baltic Sea in northern Europe. BALTEX aims to provide a better understanding of the processes of the climate system and to improve and to validate the water cycle in regional numerical models for weather forecasting and climate studies. A major effort is undertaken to couple interactively the atmosphere with the vegetated continental surfaces and the Baltic Sea including its sea ice. The intensive observational and modeling phase BRIDGE, which is a contribution to the Coordinated Enhanced Observing Period of GEWEX, will provide enhanced datasets for the period October 1999–February 2002 to validate numerical models and satellite products. Major achievements have been obtained in an improved understanding of related exchange processes. For the first time an interactive atmosphere–ocean–land surface model for the Baltic Sea was tested. This paper reports on major activities and some results.

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Catherine A. Senior
,
John H. Marsham
,
Ségolène Berthou
,
Laura E. Burgin
,
Sonja S. Folwell
,
Elizabeth J. Kendon
,
Cornelia M. Klein
,
Richard G. Jones
,
Neha Mittal
,
David P. Rowell
,
Lorenzo Tomassini
,
Théo Vischel
,
Bernd Becker
,
Cathryn E. Birch
,
Julia Crook
,
Andrew J. Dougill
,
Declan L. Finney
,
Richard J. Graham
,
Neil C. G. Hart
,
Christopher D. Jack
,
Lawrence S. Jackson
,
Rachel James
,
Bettina Koelle
,
Herbert Misiani
,
Brenda Mwalukanga
,
Douglas J. Parker
,
Rachel A. Stratton
,
Christopher M. Taylor
,
Simon O. Tucker
,
Caroline M. Wainwright
,
Richard Washington
, and
Martin R. Willet

Abstract

Pan-Africa convection-permitting regional climate model simulations have been performed to study the impact of high resolution and the explicit representation of atmospheric moist convection on the present and future climate of Africa. These unique simulations have allowed European and African climate scientists to understand the critical role that the representation of convection plays in the ability of a contemporary climate model to capture climate and climate change, including many impact-relevant aspects such as rainfall variability and extremes. There are significant improvements in not only the small-scale characteristics of rainfall such as its intensity and diurnal cycle, but also in the large-scale circulation. Similarly, effects of explicit convection affect not only projected changes in rainfall extremes, dry spells, and high winds, but also continental-scale circulation and regional rainfall accumulations. The physics underlying such differences are in many cases expected to be relevant to all models that use parameterized convection. In some cases physical understanding of small-scale change means that we can provide regional decision-makers with new scales of information across a range of sectors. We demonstrate the potential value of these simulations both as scientific tools to increase climate process understanding and, when used with other models, for direct user applications. We describe how these ground-breaking simulations have been achieved under the U.K. Government’s Future Climate for Africa Programme. We anticipate a growing number of such simulations, which we advocate should become a routine component of climate projection, and encourage international coordination of such computationally and human-resource expensive simulations as effectively as possible.

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