Response ofthe landscape to intense rainfall events is a complex and poorly understood problem. An understanding ofthe spatial variability ofrunoff generated by such storms at the hillslope scale is a necessary goal ifpatterns ofrunoffand soil erosion are to be understood at the field and catchment scale also. In recent years, it has been recognised that Unking these scales ofrunoffmay provide an approach by which accurate predictions may be made at all scales from the small hillslope to the large catchment (Wainwright et al. 2001). Furthermore, by studying the way in which patterns ofrunoffvary with spatial scale a better understanding ofsediment delivery problems and the dynamic connectivity ofsystems at a variety of scales can also be made. To address the issue of scaling within runoff, a series ofnested experiments was carried out to monitor the flux ofrunoff after intense, natural rainfall events at a range ofscales at the Walnut Gulch Experimental Watershed in die semi-arid south western US. Data from these experiments were used to evaluate a Brazier is a Lecturer in Physical Geography, Department ofGeography, University of Sheffield, Sheffield, S10 2TN, UK. E-mail: richard.brazier@shef.ac.uk. Wainwright is a Professor in Physical Geography, King's College London. Parsons is a Professor of Physical Geography, Leciester University. Powell is a Lecturer in Physical Geography, Leicester University. Simanton and Larsen are both retired from the U.S. Department of Agriculture, Agricultural Research Service, Southwest Watershed Research Center, Tucson, AZ 8S719. distributed, dynamic, process-based model, previously shown to perform well at the plot scale on semi-arid shrubland (Parsons et al. 1996). To extend previous work, the model was applied to sites ranging in size from 2 m2 up to 0.5 km2 to investigate model response to changes in scale and to provide a means ofUnking predictions made at the hillslope scale with those made at the catchment scale. Results indicate that given high quality input data accurate predictions can be made at a range ofhillslope lengths. Limitations focus upon high data requirements, though remote sensing techniques are being developed to reduce time spent on data capture ofsurface condition parameters. Scaling of erosion and sediment transport is being investigated also using a unified approach that uses characteristics oftransport distances to provide an inherent scaling factor. Initial results ofthe runoffmodelling are presented as a basis for future development ofthe erosion model.

Local government plays an important role in facilitating adaptation to climate change at the community and regional level. Experiences and lessons from New Zealand suggest that the following elements together contribute to an enabling environment for local government: (I) raising community awareness of climate change; (2) engaging and developing the local expertise of professionals and decision-makers by presenting climate change science, scenarios and their uncertainties in locally relevant contexts and through interactive workshops; (3) adoption of a sequential approach to assess risks and identify vulnerabilities in the context of other socioeconomic and location-specific pressures; and (4) support from central government through regulation and guidance material. We outline the measures undertaken in each of those areas and discuss remaining barriers and uncertainties.

Recognising ethics to help a constructive climate change debate.

Difficulties commonly encountered in precipitation measurement by radar include errors from radar reflections from the surface, errors in extrapolating from measurements aloft, and errors through inadequately sampling a fluctuating signal. These error sources are discussed, along with the skill of the solutions that have been implemented. Copyright © 2005 Royal Meteorological Society

Techniques are assessed for analysing the skill with which weather radar data can be extrapolated to provide short-term rainfall forecasts. In addition to visual inspection, forecast skill is assessed using catchment-averaged statistics - comparing analyses with rain gauge averages, forecasts with analyses and forecast river flow with measured flow. Copyright (C) 2005 Royal Meteorological Society

The limited accuracy of current cloud microphysics sensors used in cirrus cloud studies imposes limitations on the use of the data to examine the cloud’s broadband radiative behaviour, an important element of the global energy balance. We review the limitations of the instruments, PMS probes, most widely used for measuring the microphysical structure of cirrus clouds and show the effect of these limitations on descriptions of the cloud radiative properties. The analysis is applied to measurements made as part of the European Cloud and Radiation Experiment (EUCREX) to determine mid-latitude cirrus microphysical and radiative properties.

The performance of measurement systems for small ice crystals is an important issue because of the need to characterize cirrus cloud microphysics for climate research. In a cloud formed of small quasi-spherical ice particles, as found in recently formed aircraft contrails, the PMS FSSP probe gives reliable measurements consistent with other probes. This is in contrast to the expectation, based on earlier work by others, that the FSSP measurements are unreliable when ice is present in the cloud. In natural cirrus on the other hand, where there are irregular large ice particles, the FSSP indeed gives the exaggerated response reported earlier. Here simple criteria by which the presence of spherically shaped small ice particles can be recognized are proposed. There criteria provide a useful indication of the occasions in ice clouds when FSSP measurements can be relied on.

By combining AVHRR data from the NOAA satellites with information from a database of in situ measurements, large-scale maps can be generated of the microphysical parameters most immediately significant for the modelling of global circulation and climate. From the satellite data, the clouds can be classified into cumuliform, stratiform and cirrus classes and then into further sub-classes by cloud top temperature. At the same time a database of in situ measurements made by research aircraft is classified into the same sub-classes and a statistical analysis is used to derive relationships between the sub-classes and the cloud microphysical properties. These two analyses are then linked to give estimates of the microphysical properties of the satellite observed clouds. Examples are given of the application of this technique to derive maps of the probability of occurrence of precipitating clouds and of precipitating water content derived from a case study within the International Cirrus Experiment (ICE) held in 1989 over the North Sea.