Guichard F.,Meteo - France |
Asencio N.,Meteo - France |
Peugeot C.,IRD Montpellier |
Bock O.,LAREG IGN |
And 20 more authors.
Weather and Forecasting | Year: 2010
An evaluation of precipitation and evapotranspiration simulated by mesoscale models is carried out within the African Monsoon Multidisciplinary Analysis (AMMA) program. Six models performed simulations of a mesoscale convective system (MCS) observed to cross part of West Africa in August 2005. Initial and boundary conditions are found to significantly control the locations of rainfall at synoptic scales as simulated with either mesoscale or global models. When initialized and forced at their boundaries by the same analysis, all models forecast a westward-moving rainfall structure, as observed by satellite products. However, rainfall is also forecast at other locations where none was observed, and the nighttime northward propagation of rainfall is not well reproduced. There is a wide spread in the rainfall rates across simulations, but also among satellite products. The range of simulated meridional fluctuations of evapotranspiration (E) appears reasonable, but E displays an overly strong zonal symmetry. Offline land surface modeling and surface energy budget considerations show that errors in the simulated E are not simply related to errors in the surface evaporative fraction, and involve the significant impact of cloud cover on the incoming surface shortwave flux. The use of higher horizontal resolution (a few km) enhances the variability of precipitation, evapotranspiration, and precipitable water (PW) at the mesoscale. It also leads to a weakening of the daytime precipitation, less evapotranspiration, and smaller PW amounts. The simulated MCS propagates farther northward and somewhat faster within an overall drier atmosphere. These changes are associated with a strengthening of the links between PW and precipitation. © 2010 American Meteorological Society.
Harris C.A.,Brunel University |
Scott A.P.,CEFAS Weymouth Laboratory |
Johnson A.C.,CEH |
Panter G.H.,Astra Zeneca Brixham Environmental Laboratory |
And 3 more authors.
Environmental Science and Technology | Year: 2014
We have become progressively more concerned about the quality of some published ecotoxicology research. Others have also expressed concern. It is not uncommon for basic, but extremely important, factors to apparently be ignored. For example, exposure concentrations in laboratory experiments are sometimes not measured, and hence there is no evidence that the test organisms were actually exposed to the test substance, let alone at the stated concentrations. To try to improve the quality of ecotoxicology research, we suggest 12 basic principles that should be considered, not at the point of publication of the results, but during the experimental design. These principles range from carefully considering essential aspects of experimental design through to accurately defining the exposure, as well as unbiased analysis and reporting of the results. Although not all principles will apply to all studies, we offer these principles in the hope that they will improve the quality of the science that is available to regulators. Science is an evidence-based discipline and it is important that we and the regulators can trust the evidence presented to us. Significant resources often have to be devoted to refuting the results of poor research when those resources could be utilized more effectively. © 2014 American Chemical Society.
Norton L.,UK Center for Ecology and Hydrology |
Greene S.,UK Center for Ecology and Hydrology |
Scholefield P.,UK Center for Ecology and Hydrology |
Ecological Indicators | Year: 2015
Understanding the interactions between ecosystems and their underlying environmental constraints, the services which they provide, and the people benefiting from those services, are essential for the effective management and sustainability of socio-ecosystems (ecosystems which support and are impacted upon by humans). Ecosystem service (ES) indicators attempt to provide a means of measuring service provision, but the scale at which they are developed is likely to impact on how they can be used to influence the effective management of socio-ecosystems. This paper compares science and practice in the development of service measures at contrasting scales in: (a) an active research project, focused on local catchment management to improve water quality at Loweswater in the English Lake District, and (b) a science-based study developing national scale indicators of water quality using the Countryside Survey dataset.The paper explores different approaches taken towards the production of ecological measures, which inform on either single or multiple ES delivery across the land/water interface, dependent on scale. It considers how scale impacts on the process of gathering data and on the types of data which can contribute to ES indicators. It further reflects on how service indicators representing different scales of study may be used and by whom. Local scales, in this case the catchment scale, provide a valuable socio-ecological unit for exploring ES delivery, but the extent to which ecosystem service indicators may be used by local actors is uncertain. Larger scale studies may be confined to single services by virtue of data availability but can provide useful policy tools for targeting action. The paper concludes that 'scale' is an important consideration when developing ES indicators. It also concludes that questions around the utility of such indicators should consider the relevance of scale and how it relates to governance. © 2015 Elsevier Ltd.
Kergoat L.,French National Center for Scientific Research |
Grippa M.,French National Center for Scientific Research |
Baille A.,Technical University of Cartagena |
Eymard L.,University Pierre and Marie Curie |
And 11 more authors.
Atmospheric Science Letters | Year: 2011
This article summarises the scientific results gained from the satellite observation of the land surface during African Monsoon Multidisciplinary Analysis (AMMA). Validation of existing satellite products as well as developments of new algorithms are reported, spanning surface and total soil moisture, surface energy balance and radiation fluxes, vegetation properties and land cover (LC). The use of remote sensing data for investigating land-atmosphere interactions, for retrieving the components of continental water cycle and for evaluating Land Surface Models (LSM) is illustrated. The contribution of satellite data to the detection of decadal trends is also highlighted, revealing intriguing results and open questions. Copyright © 2011 Royal Meteorological Society.
Blyth E.M.,CEH |
Jacobs C.M.J.,Wageningen University
IAHS-AISH Publication | Year: 2011
There is a need to include the atmospheric feedbacks that alter evaporative demand in a region when water availability is changed. This is because the water resource implications of large-scale irrigation or soil water depletion cannot be assessed unless the subsequent changes to air temperature, humidity and cloudiness are accounted for. Here, we propose a simple tool that can be used to assess such feedback strengths anywhere in the globe, although it will not always be appropriate. The tool is based on a simple box model for the planetary boundary layer, assuming a semi-permeable lid at the top, but taking advection into account as well. Sample calculations with a prototype of the tool and an analysis of atmospheric data in North America showed that atmospheric feedbacks can play an important role in water resource assessments in some regions. If the region has a relatively straightforward feedback regime dominated by one-dimensional feedback processes, this can be quantified using the simple tool. © 2011 IAHS Press.