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Coping with Spatial heterogeneity and Non-stationarity of Rainfall: A Fresh View to High Resolution Precipitation Simulations over Large Domains
No full textFlood is a major peril in UK and Europe and as such, the realistic and statistically consistent simulation of its driving force, the precipitation, is of particular importance. Statistical coherence of precipitation simulations is even more important in the context of aggregate flood risk and corresponding extreme
economic losses because these are result of the interplay between local intensities, spatial clustering and areal coverage of precipitation footprints. This interplay is further complicated by the fact that rainfall fields are spatially heterogeneous and non-stationary when considered at short time scales. The purpose of this presentation is to introduce a novel modeling approach to large scale - high resolution precipitation simulations which is computationally feasible for thousands annual realizations under the current climate conditions. The model preserves the rainfall patterns at large scales and incorporates anisotropic downscaling localized in space and time to preserve the non-stationary nature of the local precipitation variability. The entire simulation process is conducted in the domain of a Gaussian copula in order to deal with the inherent spatial heterogeneity of rainfall fields
Institute of Physics, Environmental Physics Group newsletter (41), October 2009
No full textThis file contains the newsletters of the Environmental Physics Group at the Institute of Physics. The fundamental aim of the Group is to promote physics within the context of the environmental sciences. In achieving this aim we provide a forum for the discussion of physics as it applies to the environment and encourage the development and application of physical methods to environmental research. The Group also encourages the education and training of physicists in the environmental sciences through meetings and contacts with educationalists at all levels. Because of the broad nature of environmental physics the Group is involved in co-operative meetings with other professional organisations with interests in the environment. These newsletters are an archive of our activities since the formation of the Group. For more information about the Environmental Physics Group, see http://www.iop.org/activity/groups/subject/env/index.htm
Interpretation for use of surface wind speed projections from the 11-member Met Office Regional Climate Model ensemble
No full textThis document is for use with the UK Climate Projections 2009 (UKCP09) data. It provides technical information to aid users in the interpretation of surface wind speed projections from the 11-member Met Office Regional Climate Model ensemble
JCAMP-DC format documentation formerly on BADC website
No full textThis webpage describes the JCAMP-DX (The joint Committee on Atomic and Molecular Physical data – Data Exchange) format following an internal review by CEDA for the suitability of this format for long-term archiving within CEDA's archives
Detailed analysis of valley flows in complex terrain - A case study from the COPS field experiment
No full textThe Convective & Orographically-induced Precipitation Study (COPS) was a large international field campaign that took place in the complex low-mountain region of the Black Forest, Germany, during summer 2007. Intensive Observations Period (IOP) 9c 20th July, & aimed to observe the development & modification of a Mesoscale Convective System (MCS), which had convection embedded within its frontal zone, as it passed over the COPS region from south-west to north-east.
A gust front, emanating from MCS outflow, together with orographic lifting & a thermally-driven convergence line combined to generate an arc of severe convective activity east of the COPS region & ahead of the MCS. In-situ & remote sensing surface observations show that the complex COPS orography significantly modified the shape, structure & path of the gust front. This, in turn, locally enhanced the pre-frontal convergence zone, eventually leading to convective initiation.
This paper will discuss the way in which the MCS gust front became decoupled from the synoptic flow aloft. Observations show substantial differences in the magnitude & direction of the gust front between sites located on mountain tops & those located in valleys. Differences between valley sites are also identified depending on the valley orientation. Valleys aligned perpendicular to the synoptic-scale MCS track appear to be sheltered from the gust front by steep valley gradients. Valleys in the eastern COPS region that are roughly aligned parallel to the MCS track, appear to organise the path of the gust front out of the Black Forest & into the regions of strong convergence where the convective cells subsequently form. Flow features are explained & further analysed by comparison with high resolution simulations of the IOP using the Weather Research & Forecasting numerical model (WRF)
Decadal Climate Variability associated with the Meridional Overturning Circulation and the North Atlantic Oscillation in a new Climate Model (CHIME)
No full textUsing statistical analysis, the study investigates the decadal variability in the Atlantic Meridional Overturning Circulation (AMOC) and the North Atlantic Oscillation (NAO) in a new-coupled climate model CHIME developed at the National Oceanography Centre, Southampton.
Because of the well-known contribution of both the AMOC and NAO to the mild climate of Atlantic European region, understanding the mechanism leading to their strong variability is pre-requisite for developing decadal predictions. However, although it has been shown that the multidecadal AMOC fluctuations are associated with a spatial pattern of surface heat flux variations that bear a strong resemblance to the NAO, no conclusive evidence has yet been found that the AMOC variability is part of a dynamically coupled atmosphere-ocean mode.
Therefore in this study, the mechanisms responsible for decadal variability and links between the AMOC and NAO are investigated using CHIME. This model is as similar as possible to HadCM3 with the important exception that the ocean component has been replaced by the Hybrid-coordinate model HYCOM. The dependence of simulated AMOC and NAO variability on ocean model type is thus addressed for the first time.
Overall CHIME shows strong decadal variability in both the AMOC and the NAO, which can be of considerable interested from the perspective of decadal climate predictability