Use of very high resolution climate model data for hydrological modelling: estimation of potential evaporation

Climate model data are increasingly used to drive hydrological models, to assess the possible impacts of climate change on river flows. Hydrological models often require potential evaporation (PE) from vegetation, alongside precipitation, but PE is not usually output by climate models so has to be estimated from other meteorological variables. Here, the Penman-Monteith formula is applied to estimate PE using data from a 12 km Regional Climate Model (RCM) and a nested very high resolution (1.5 km) RCM covering southern Britain. PE estimates from RCM runs driven by reanalysis boundary conditions are compared to observation-based PE data, to assess performance. The comparison shows that both the 1.5 and 12 km RCMs reproduce observation-based PE well, on daily and monthly time-steps, and enables choices to be made about application of the formula using the available data. Data from Current and Future RCM runs driven by boundary conditions from a Global Climate Model are then used to investigate potential future changes in PE, and how certain factors affect those changes. In particular, the importance of including changes in canopy resistance is demonstrated. PE projections are also shown to vary to some extent according to how aerosols are modelled in the RCMs

A New Opisthobranch Mollusc from Hawaii

Volume: 15Start Page: 112End Page: 11

Snow in Britain: the historical picture and future projections

• The formation of snow is a complex process. Snow that reaches the ground can melt quickly or remain for periods from days to months, but most of Britain does not usually experience sustained periods of lying snow, and there are strong year-to-year variations. • Climate change is likely to have a significant effect on snow and ice processes globally. The areas most effected are likely to be those where current winter temperatures are close to 0°C, including parts of upland Britain. There is evidence of decreasing trends in observations of snowfall and lying snow in Britain, and climate model projections suggest a continuation of this trend. • Snow can affect river flows (quantity and quality). Although flows in Britain are generally dominated by rainfall rather than snowmelt, some catchments in the Scottish Highlands have a significant snowmelt contribution. • There is evidence of changes in observed and projected river flows in some catchments in Britain, linked to changes in snow, although it can be difficult to distinguish the effects of snow changes from those of other concurrent changes (climatic and non-climatic). Flow regime changes in catchments heavily affected by snow usually involve increases in winter flow and decreases in spring flow, but the effect on catchments with more transient snow cover is less clear, as is the effect on high flows and water quality. • Snow can also affect a number of other factors of socio-economic or environmental importance (e.g. transport and farming). There is some evidence that disruption due to snow may be less frequent in future, but in many cases disruption from other types of weather event may increase. • Further modelling of the potential impacts of climate change, including modelling the influence of snow changes as well as other climatic and non-climatic changes, would aid adaptation and encourage mitigation. • The impacts of snow tend to be worse in areas where events occur less frequently, due to unpreparedness. There is a need to guard against complacency when it comes to future snow events in Britain, which will still occur despite a likely reduction in frequency

A review of snow in Britain: the historical picture and future projections

Climate change is likely to have a significant effect on snow globally, with most effect where current winter temperatures are close to 0°C, including parts of upland Britain. There is evidence of decreasing trends in observations of snowfall and lying snow in Britain, and climate projections suggest a continuation of this trend. Although river flows in Britain are generally dominated by rainfall rather than snowmelt, some upland catchments have a significant snowmelt contribution. There is evidence of changes in observed and projected river flows in some catchments in Britain, linked to changes in snow, but it can be difficult to distinguish the effects of snow changes from those of other concurrent changes (climatic and non-climatic). Flow regime changes in catchments with widespread and prolonged winter snow cover usually involve increases in winter flow and decreases in spring flow, but the effect on catchments with more transient snow cover is less clear, as is the effect on high flows and water quality. Snow can also affect a number of other factors of socio-economic or environmental importance (e.g. transport and farming). There is some evidence that disruption due to snow may be less frequent in the future, but disruption from other types of weather events may increase. The impacts of snow tend to be worse in areas where events occur less frequently, due to unpreparedness, so there is a need to guard against complacency when it comes to future snow events in Britain, which can still be expected despite a likely reduction in frequency. Further modelling of the potential impacts of climate change, including modelling the influence of snow changes as well as other climatic and non-climatic changes, would aid adaptation and encourage mitigation

Use of very high resolution climate model data for hydrological modelling in southern Britain

Previous work driving hydrological models directly with data from regional climate models (RCMs) used data on an approximately 25x25km grid, which generally required some form of further downscaling before use by hydrological models. Recently, higher resolution data have become available from a NERC Changing Water Cycle project, CONVEX. As part of that project the Met Office Hadley Centre has run a very high resolution (1.5km) RCM, nested in a 12km RCM driven by ERA-Interim boundary conditions (1989-2008). They have also run baseline and future climate scenarios, nesting the RCMs in a global climate model. The 12km RCM runs cover Europe, while the 1.5km RCM runs only cover southern Britain

Hyperspectral imaging for erosion detection in wind turbine blades

Inspection of wind turbine blades is required to identify any defects or failures and decide on any remedial actions e.g. blade repair or replacement. Traditionally, inspections have been performed by rope access technicians who visually inspect the blades and record damage using standard photographic equipment. Recent developments have seen an increase in popularity in the use of remote based inspection techniques using ground mounted cameras and cameras installed on Remotely Operated Aerial Vehicles, more commonly referred to as drones. Whilst these techniques remove the need for human access to the blades, imaging is performed remotely and does not always provide adequate image quality using standard high definition cameras. As a result, there is a growing interest in imaging techniques based on other regions of the electromagnetic spectrum. Laboratory and field based trials are required to properly examine this potential and understand which frequencies can be applied to imaging blades. This paper demonstrates a Hyperspectral Imaging technique in its application to imaging surface defects on a section of wind turbine blade in a laboratory