Staff Publications

Staff Publications

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    'Staff publications' is the digital repository of Wageningen University & Research

    'Staff publications' contains references to publications authored by Wageningen University staff from 1976 onward.

    Publications authored by the staff of the Research Institutes are available from 1995 onwards.

    Full text documents are added when available. The database is updated daily and currently holds about 240,000 items, of which 72,000 in open access.

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The intractable challenge of evaluating cattle vaccination as a control for bovine tuberculosis
Conlan, Andrew James Kerr ; Vordermeier, Martin ; Jong, Mart C.M. de; Wood, James L.N. - \ 2018
eLife 7 (2018). - ISSN 2050-084X

Vaccination of cattle against bovine Tuberculosis (bTB) has been a long-term policy objective for countries where disease continues to persist despite costly test-and-slaughter programs. The potential use of vaccination within the European Union has been linked to a need for field evaluation of any prospective vaccine and the impact of vaccination on the rate of transmission of bTB. We calculate that estimation of the direct protection of BCG could be achieved with 100 herds, but over 500 herds would be necessary to demonstrate an economic benefit for farmers whose costs are dominated by testing and associated herd restrictions. However, the low and variable attack rate in GB herds means field trials are unlikely to be able to discern any impact of vaccination on transmission. In contrast, experimental natural transmission studies could provide robust evaluation of both the efficacy and mode of action of vaccination using as few as 200 animals.

Ten essentials for action-oriented and second order energy transitions, transformations and climate change research
Fazey, Ioan ; Schäpke, Niko ; Caniglia, Guido ; Patterson, James ; Hultman, Johan ; Mierlo, Barbara Van; Säwe, Filippa ; Wiek, Arnim ; Wittmayer, Julia ; Aldunce, Paulina ; Waer, Husam Al; Battacharya, Nandini ; Bradbury, Hilary ; Carmen, Esther ; Colvin, John ; Cvitanovic, Christopher ; D’Souza, Marcella ; Gopel, Maja ; Goldstein, Bruce ; Hämäläinen, Timo ; Harper, Gavin ; Henfry, Tom ; Hodgson, Anthony ; Howden, Mark S. ; Kerr, Andy ; Klaes, Matthias ; Lyon, Christopher ; Midgley, Gerald ; Moser, Susanne ; Mukherjee, Nandan ; Müller, Karl ; O’brien, Karen ; O’Connell, Deborah A. ; Olsson, Per ; Page, Glenn ; Reed, Mark S. ; Searle, Beverley ; Silvestri, Giorgia ; Spaiser, Viktoria ; Strasser, Tim ; Tschakert, Petra ; Uribe-Calvo, Natalia ; Waddell, Steve ; Rao-Williams, Jennifer ; Wise, Russel ; Wolstenholme, Ruth ; Woods, Mel ; Wyborn, Carina - \ 2018
Energy Research & Social Science 40 (2018). - ISSN 2214-6296 - p. 54 - 70.
The most critical question for climate research is no longer about the problem, but about how to facilitate the transformative changes necessary to avoid catastrophic climate-induced change. Addressing this question, however, will require massive upscaling of research that can rapidly enhance learning about transformations. Ten essentials for guiding action-oriented transformation and energy research are therefore presented, framed in relation to second-order science. They include: (1) Focus on transformations to low-carbon, resilient living; (2) Focus on solution processes; (3) Focus on ‘how to’ practical knowledge; (4) Approach research as occurring from within the system being intervened; (5) Work with normative aspects; (6) Seek to transcend current thinking; (7) Take a multi-faceted approach to understand and shape change; (8) Acknowledge the value of alternative roles of researchers; (9) Encourage second-order experimentation; and (10) Be reflexive. Joint application of the essentials would create highly adaptive, reflexive, collaborative and impact-oriented research able to enhance capacity to respond to the climate challenge. At present, however, the practice of such approaches is limited and constrained by dominance of other approaches. For wider transformations to low carbon living and energy systems to occur, transformations will therefore also be needed in the way in which knowledge is produced and used.
Climate change effects on wildland fire risk in the Northeastern and Great Lakes states predicted by a downscaled multi-model ensemble
Kerr, Gaige Hunter ; DeGaetano, Arthur T. ; Stoof, Cathelijne R. ; Ward, Daniel - \ 2018
Theoretical and Applied Climatology 131 (2018)1-2. - ISSN 0177-798X - p. 625 - 639.

This study is among the first to investigate wildland fire risk in the Northeastern and the Great Lakes states under a changing climate. We use a multi-model ensemble (MME) of regional climate models from the Coordinated Regional Downscaling Experiment (CORDEX) together with the Canadian Forest Fire Weather Index System (CFFWIS) to understand changes in wildland fire risk through differences between historical simulations and future projections. Our results are relatively homogeneous across the focus region and indicate modest increases in the magnitude of fire weather indices (FWIs) during northern hemisphere summer. The most pronounced changes occur in the date of the initialization of CFFWIS and peak of the wildland fire season, which in the future are trending earlier in the year, and in the significant increases in the length of high-risk episodes, defined by the number of consecutive days with FWIs above the current 95th percentile. Further analyses show that these changes are most closely linked to expected changes in the focus region’s temperature and precipitation. These findings relate to the current understanding of particulate matter vis-à-vis wildfires and have implications for human health and local and regional changes in radiative forcings. When considering current fire management strategies which could be challenged by increasing wildland fire risk, fire management agencies could adapt new strategies to improve awareness, prevention, and resilience to mitigate potential impacts to critical infrastructure and population.

Key determinants and integrated regional solutions of current and potential future mobilisation : Synthesis report (WP D3.3 Simwood Progress report)
Kerr, Gary ; Schelhaas, M. ; Nabuurs, G.J. - \ 2017
Freising : Bayerische Landesanstalt für Wald und Forstwirtschaft - 23 p.
Aetiology and progression of cancer: Role of body fatness, physical activity, diet, and other lifestyle factors
Duijnhoven, F.J.B. van; Kampman, E. - \ 2016
In: Oxford Textbook of Oncology / Kerr, David J., Haller, Daniel G., van de Velde, C.J.H., Baumann, M., Oxford University Press - ISBN 9780199656103
Worldwide, there is a large difference in cancer rates. These rates may change over generations when people move from one part of the world to another. This occurs because these generations adapt their lifestyle to that of the host country, indicating that lifestyle factors are important in the aetiology of cancer. In this chapter an overview of established associations between body fatness, physical activity, diet, and other lifestyle factors and the development of cancer is given. About one-third of all cancers worldwide are caused by an unhealthy lifestyle. Evidence-based recommendations for the general population to decrease their risk of cancer have been set. Guidelines for individuals who are diagnosed with cancer, however, are lacking, due to limited evidence on the role of lifestyle during and after cancer treatment. Research should now be directed towards the role of body fatness, physical activity, diet, and other lifestyle factors in cancer progression.
Lessons learned from practical approaches to reconcile mismatches between biological population structure and stock units of marine fish
Kerr, Lisa A. ; Hintzen, Niels T. ; Cadrin, Steven X. ; Clausen, Lotte Worsøe ; Dickey-Collas, Mark ; Goethel, Daniel R. ; Hatfield, Emma M.C. ; Kritzer, Jacob P. ; Nash, Richard D.M. - \ 2016
ICES Journal of Marine Science 74 (2016)6. - ISSN 1054-3139 - p. 1708 - 1722.
Biocomplexity - Connectivity - Fisheries management - Population structure - Spatial structure - Stock assessment - Stock identification

Recent advances in the application of stock identification methods have revealed inconsistencies between the spatial structure of biological populations and the definition of stock units used in assessment and management. From a fisheries management perspective, stocks are typically assumed to be discrete units with homogeneous vital rates that can be exploited independently of each other. However, the unit stock assumption is often violated leading to spatial mismatches that can bias stock assessment and impede sustainable fisheries management. The primary ecological concern is the potential for overexploitation of unique spawning components, which can lead to loss of productivity and reduced biodiversity along with destabilization of local and regional stock dynamics. Furthermore, ignoring complex population structure and stock connectivity can lead to misperception of the magnitude of fish productivity, which can translate to suboptimal utilization of the resource. We describe approaches that are currently being applied to improve the assessment and management process for marine fish in situations where complex spatial structure has led to an observed mismatch between the scale of biological populations and spatially-defined stock units. The approaches include: (i) status quo management, (ii) "weakest link" management, (iii) spatial and temporal closures, (iv) stock composition analysis, and (v) alteration of stock boundaries. We highlight case studies in the North Atlantic that illustrate each approach and synthesize the lessons learned from these real-world applications. Alignment of biological and management units requires continual monitoring through the application of stock identification methods in conjunction with responsive management to preserve biocomplexity and the natural stability and resilience of fish species.

Framing the concept of satellite remote sensing essential biodiversity variables: challenges and future directions
Pettorelli, Nathalie ; Wegmann, Martin ; Skidmore, Andrew ; Mücher, Sander ; Dawson, Terence P. ; Fernandez, Miguel ; Lucas, Richard ; Schaepman, Michael E. ; Wang, Tiejun ; O'Connor, Brian ; Jongman, Robert H.G. ; Kempeneers, Pieter ; Sonnenschein, Ruth ; Leidner, Allison K. ; Böhm, Monika ; He, Kate S. ; Nagendra, Harini ; Dubois, Grégoire ; Fatoyinbo, Temilola ; Hansen, Matthew C. ; Paganini, Marc ; Klerk, Helen M. De; Asner, Gregory P. ; Kerr, Jeremy T. ; Estes, Anna B. ; Schmeller, Dirk S. ; Heiden, Uta ; Rocchini, Duccio ; Pereira, Henrique M. ; Turak, Eren ; Fernandez, Nestor ; Lausch, Angela ; Cho, Moses A. ; Alcaraz-segura, Domingo ; Mcgeoch, Mélodie A. ; Turner, Woody ; Mueller, Andreas ; St-Louis, Véronique ; Penner, Johannes ; Vihervaara, Petteri ; Belward, Alan ; Reyers, Belinda ; Geller, Gary N. - \ 2016
Remote Sensing in Ecology and Conservation 2 (2016)3. - ISSN 2056-3485 - p. 122 - 131.
Although satellite-based variables have for long been expected to be key components to a unified and global biodiversity monitoring strategy, a definitive and agreed list of these variables still remains elusive. The growth of interest in biodiversity variables observable from space has been partly underpinned by the development of the essential biodiversity variable (EBV) framework by the Group on Earth Observations – Biodiversity Observation Network, which itself was guided by the process of identifying essential climate variables. This contribution aims to advance the development of a global biodiversity monitoring strategy by updating the previously published definition of EBV, providing a definition of satellite remote sensing (SRS) EBVs and introducing a set of principles that are believed to be necessary if ecologists and space agencies are to agree on a list of EBVs that can be routinely monitored from space. Progress toward the identification of SRS-EBVs will require a clear understanding of what makes a biodiversity variable essential, as well as agreement on who the users of the SRS-EBVs are. Technological and algorithmic developments are rapidly expanding the set of opportunities for SRS in monitoring biodiversity, and so the list of SRS-EBVs is likely to evolve over time. This means that a clear and common platform for data providers, ecologists, environmental managers, policy makers and remote sensing experts to interact and share ideas needs to be identified to support long-term coordinated actions.
Modeling and participatory farmer-led approaches to food security in a changing world: A case study from Malawi
Snapp, S. ; Kerr, R.B. ; Smith, A. ; Ollenburger, M.H. ; Mhango, W. ; Shumba, L. ; Gondwe, T. ; Kanyama-Phiri, G.Y. - \ 2013
Science Planétaire - Sécheresse 24 (2013)4. - ISSN 1147-7806 - p. 350 - 358.
Crop diversification has a long history in Africa, as a foundation for more resilient and sustainable farming systems. However, success has often been mixed. Variable weather and changing climate requires a focus on supporting farmer capacity to adapt and innovate. Participatory research and simulation modeling are uniquely suited to this goal. Here we present a case study from Northern Malawi where crop modeling in conjunction with participatory approaches were used to evaluate the performance of the promising mixed cropping systems, involving maize and pigeon pea. Using historical rainfall records, simulated yield (Agricultural Production Systems Simulator, APSIM) from maize and pigeon pea-maize intercrop and rotation systems was compared to food requirements for 12 households selected to represent a range of wealth status.Wefound that pigeon pea-maize intercrops were highly likely to produce sufficient calories for smallholder households across variable rainfall patterns, from 73 to 100% of the years simulated, for 10 out of 12 case study households. This stands in contrast to monoculturemaize,where sufficient calories were consistently produced for only half of the case study households. Survey data from this case study documented adoption patterns that reflected strong interest in legume mixtures, and gains in farmer capacity. Farmers shared agronomic information and seeds of pigeon pea and other improved legumes. Overall, we found that farmers were highly motivated to experiment with and adopt legumes that produced food and other valued combinations of traits, whereas green manures met with limited interest. Notably, farmers prioritized species that were reliable at producing food under variable rainfall. Support for farmer-to-farmer learning was critical to the success of the project, and a co-learning approach provided valuable insights to researchers regarding which technologies were more adaptable, and ultimately, adoptable by smallholders living in a highly variable environment.
Genetic control of interactions among individuals: contrasting outcomes of indirect genetic effects arising from neighbour disease infection and competition in a forest tree
Costa e Silva, J. ; Potts, B.M. ; Bijma, P. ; Kerr, R.J. ; Pilbeam, D.J. - \ 2013
New Phytologist 197 (2013)2. - ISSN 0028-646X - p. 631 - 641.
eucalyptus-globulus - multilevel selection - mycosphaerella-nubilosa - ecological interactions - arabidopsis-thaliana - heritable variation - evolution - model - life - consequences
Indirect genetic effects (IGEs) are heritable effects of individuals on trait values of their conspecifics. IGEs may substantially affect response to selection, but empirical studies on IGEs are sparse and their magnitude and correlation with direct genetic effects are largely unknown in plants. Here we used linear mixed models to estimate genetic (co)variances attributable to direct and indirect effects for growth and foliar disease damage in a large pedigreed population of Eucalyptus globulus. We found significant IGEs for growth and disease damage, which increased with age for growth. The correlation between direct and indirect genetic effects was highly negative for growth, but highly positive for disease damage, consistent with neighbour competition and infection, respectively. IGEs increased heritable variation by 71% for disease damage, but reduced heritable variation by 85% for growth, leaving nonsignificant heritable variation for later age growth. Thus, IGEs are likely to prevent response to selection in growth, despite a considerable ordinary heritability. IGEs change our perspective on the genetic architecture and potential response to selection. Depending on the correlation between direct and indirect genetic effects, IGEs may enhance or diminish the response to natural or artificial selection compared with that predicted from ordinary heritability.
Soil moisture-precipitation coupling: observations question an impact on precipitation occurrence in North America
Guillod, B.P. ; Miralles, D.G. ; Dolman, H. ; Reichstein, M. ; Teuling, A. ; Hurk, B. van den; Buchmann, N. ; Seneviratne, S.I. - \ 2013
The coupling between soil moisture and convective precipitation through indirect mechanisms (e.g. boundary-layer growth and convection triggering) remains a key challenge out of numerous aspects on the interactions between the land surface and precipitation. In particular, how surface turbulent fluxes (sensible, latent heat fluxes and their partitioning) impact the occurrence of rainfall is poorly understood, due to the number and diversity of the processes involved. Here we explore the relationship between Evaporative Fraction (EF) and precipitation occurrence on the daily time scale. We apply a recently developed method (Findell et al., 2011) to observational data in North America: EF derived from FLUXNET sites and from GLEAM (satellite-based estimates), and radar precipitation data from NEXRAD. We then compare the resulting estimate of land-precipitation coupling to the NARR reanalysis (North American Regional Reanalysis). While a strong relationship is found in NARR, observations do not confirm a strong impact of EF on precipitation occurrence (i.e., no significant coupling is found). Further analyses show that, while precipitation data from NARR and NEXRAD agree well, EF data from the different sources differ widely and lead to different coupling. This questions the existence of a positive coupling between EF and precipitation occurrence in North America and highlights the need for more reliable datasets of high spatial and temporal resolution to fully quantify the strength of such land-surface atmosphere coupling. References: Findell, K. L., P. Gentine, B. R. Lintner, and C. Kerr. 2011. Probability of afternoon precipitation in eastern United States and Mexico enhanced by high evaporation. Nature Geosci, 4, 434-439.
Evaluating perennial ryegrass cultivars: improving testing
Kerr, G.A. ; Chapman, D.F. ; Thom, E.R. ; Matthew, C. ; Linden, A. van der; Baird, D.B. ; Johnston, E. ; Corkran, J.R. - \ 2012
In: Proceedings of the New Zealand Grassland Association, Gore, New Zealand, 5-8 November 2012. - - p. 127 - 136.
Anguillid herpesvirus 1 transcriptome
Beurden, S.J. van; Gatherer, D. ; Kerr, K. ; Galbraith, J. ; Herzyk, P. ; Peeters, B.P.H. ; Rottier, P.J.M. ; Engelsma, M.Y. ; Davidson, A.J. - \ 2012
Journal of Virology 86 (2012)18. - ISSN 0022-538X - p. 10150 - 10161.
channel catfish virus - human cytomegalovirus transcriptome - european eel - structural proteins - genome sequences - gene-expression - koi herpesvirus - common carp - identification - persistence
We used deep sequencing of poly(A) RNA to characterize the transcriptome of an economically important eel virus, anguillid herpesvirus 1 (AngHV1), at a stage during the lytic life cycle when infectious virus was being produced. In contrast to the transcription of mammalian herpesviruses, the overall level of antisense transcription from the 248,526-bp genome was low, amounting to only 1.5% of transcription in predicted protein-coding regions, and no abundant, nonoverlapping, noncoding RNAs were identified. RNA splicing was found to be more common than had been anticipated previously. Counting the 10,634-bp terminal direct repeat once, 100 splice junctions were identified, of which 58 were considered likely to be involved in the expression of functional proteins because they represent splicing between protein-coding exons or between 5' untranslated regions and protein-coding exons. Each of the 30 most highly represented of these 58 splice junctions was confirmed by RT-PCR. We also used deep sequencing to identify numerous putative 5' and 3' ends of AngHV1 transcripts, confirming some and adding others by rapid amplification of cDNA ends (RACE). The findings prompted a revision of the AngHV1 genome map to include a total of 129 protein-coding genes, 5 of which are duplicated in the terminal direct repeat. Not counting duplicates, 11 genes contain integral, spliced protein-coding exons, and 9 contain 5' untranslated exons or, because of alternative splicing, 5' untranslated and 5' translated exons. The results of this study sharpen our understanding of AngHV1 genomics and provide the first detailed view of a fish herpesvirus transcriptome.
Population consequences of mutational events: effects of antibiotic resistance on the r/K trade-off
Fitzsimmons, Jay ; Schoustra, S.E. ; Kerr, Jeremy T. ; Kassen, R.K. - \ 2010
Evolutionary Ecology 24 (2010)1. - ISSN 0269-7653 - p. 227 - 236.
What are the effects of a mutational event on population dynamics? This eco-evolutionary question has relevance not only to basic biological theories but also to conservation applications. We evaluated the relationship between maximum population growth rate (rmax) and carrying capacity (K) among strains of the bacterium Pseudomonas fluorescens. Each of 65 strains differed from their common ancestor by one naturally acquired phenotypic change conferring antibiotic resistance, brought about by a single mutational event, and each was grown in isolation in four environments. We found no evidence of a trade-off between rmax and K. Rather, strains with rapid growth rates also had high carrying capacity, with little interaction between strain and environment. We conclude that the extensive variation in overall fitness resulting from single mutational events likely masks whatever population trade-offs may exist.
Effects of supplemental L-tryptophan on serotonin, cortisol, intestinal integrity, and behavior in weanling piglets
Koopmans, S.J. ; Guzik, A.C. ; Meulen, J. van der; Dekker, R.A. ; Kogut, J. ; Kerr, B.J. ; Southern, L.L. - \ 2006
Journal of Animal Science 84 (2006). - ISSN 0021-8812 - p. 963 - 971.
dietary tryptophan - salivary cortisol - amino-acids - growth-performance - laying hens - young-pigs - plasma - protein - aggression - decreases
Stress occurs in intensive pig farming when piglets are weaned and mixed. In this study, we investigated whether this stress might be reduced with elevated dietary levels of Trp. The effects of supplemental dietary Trp (5 g/kg of feed, as-fed basis) were tested on the neuroendocrine system, intestinal integrity, behavior, and growth performance in nursery pigs, both before and after mixing. Mixing occurred 5 d after weaning and diet introduction. On d 4, 5, and 6, Trp-fed pigs vs. control pigs showed approximately a 2-fold elevation in plasma Trp concentrations (68 ± 7 vs. 32 ± 2 µmol/L; P <0.001), a 38% increase in hypothalamic serotonin turnover as measured by 5-hydroxyindoleacetic acid:5-hydroxytryptamine (P <0.001), and an 11 to 18% increase (P <0.05) in the intestinal villus height:crypt depth. Before (d 4) and at (d 5) mixing, saliva but not plasma cortisol concentrations were reduced (P <0.02) by approximately 2-fold in Trp-fed pigs vs. control pigs. Intestinal paracellular (horseradish peroxidase) and transcellular (fluorescein isothiocyanate) transport of macromolecules were not affected by dietary treatment, but mixing induced a 2-fold reduction (P <0.05) in transcellular transport. Behavioral responses (lying and standing) at mixing were not affected by dietary treatment, except on d 10 after diet introduction when Trp supplementation induced more lying and less standing (P <0.02). Average daily gain and ADFI were not different among dietary groups (P > 0.10). In conclusion, supplemental dietary Trp (5 g/kg) to piglets increased hypothalamic serotonergic activity, reduced the salivary cortisol response to mixing, improved intestinal morphology, and reduced physical activity 10 d after diet introduction. Consequently, diets containing high Trp levels improved neuroendocrine components of stress and increased gastrointestinal robustness but did not affect behavioral reactivity in nursery pigs during weaning and mixing.
Comment on Hobbs and Kerr: Will consumers lose or gain from the environmental impacts of transgenic crops?
Scatasta, S. - \ 2005
In: Environmental Costs and Benefits of Transgenic Crops / Wesseler, J.H.H., Dordrecht : Springer (Wageningen UR Frontis Series 7) - ISBN 1402032471 - p. 263 - 264.
Does Ignoring Multi-Destination Trips in the Travel Cost Method Cause a Systematic Downward Bias?
Kuosmanen, T.K. ; Nillesen, E.E.M. ; Wesseler, J.H.H. - \ 2003
Wageningen : Mansholt Graduate School (Working Paper Mansholt Graduate School 9) - 29
reizen - kostenanalyse - consumentengedrag - gebruikswaarde - kosten-batenanalyse - nationale parken - bezoeken - australië - travel - cost analysis - consumer behaviour - use value - cost benefit analysis - national parks - visits - australia
In theory, treating the multi-destination trips (MDTs) as single-destination trips (SDT) does not necessarily lead to biased results, because negative effect of price increase may be offset by the shift of the estimated demand curve. However, in our empirical application of the TCM zonal model to the valuation of the economic benefits of the Bellenden Kerr National Park in Australia we find (statistically significant) evidence that ignoring the MDTs leads to a dramatic overestimation of the consumer surplus. This is in sharp contrast to the earlier empirical evidence from other type of TCM models, which have either excluded the MDT visitors from the data set or treated them as single-destination trips, suggesting the opposite conclusion.
Monitoring energy and mass transfers during the Alpilles-ReSEDA experiment
Olioso, A. ; Braud, I. ; Chanzy, A. ; Autret, H. ; Bethenot, O. ; Bonnefonds, J.M. ; Calvet, J.C. ; Courault, D. ; Demarty, J. ; Ducros, Y. ; Gaudu, J.C. ; Gonzales-Sosa, E. ; Gouget, R. ; Jongschaap, R.E.E. ; Kerr, Y.H. ; Lagouarde, J.P. ; Laurent, J.P. ; Lewan, E. ; Marloie, O. ; Mc Anneney, J. ; Moulin, S. ; Ottlé, C. ; Prévot, L. ; Thony, J.L. ; Wigneron, J.P. ; Zhao, W. - \ 2002
Agronomie 22 (2002)6. - ISSN 0249-5627 - p. 597 - 611.
soil hydraulic-properties - insitu measurement - moisture - evapotranspiration - assimilation - parameters - region - probe - model
The Alpilles-ReSeDA program was initiated to develop and test methods for interpreting remote sensing data that could lead to a better evaluation of soil and vegetation processes. This article presents the experiment that was setup in order to acquire the necessary data to achieve this goal. Intensive measurements were performed for almost one year over a small agricultural region in the South of France (20 kilometers square). To capture the main processes controlling land-atmosphere exchanges, the local climate was fully characterized, and surface energy fluxes, vegetation biomass, vegetation structure, soil moisture profiles, surface soil moisture, surface temperature and soil temperature were monitored. Additional plant physiological measurements and a full characterization of physical soil parameters were also carried out. After presenting the different types of measurements, examples are given in order to illustrate the variability of soils and plant processes in the area in response to the experienced climate
Book review of The Economics of Biotechnology by Gaisford, D., Hobbs, J.E., Kerr, W.A., Perdikis, N., Plunkett, M.D.
Wesseler, J. - \ 2002
European Review of Agricultural Economics 40 (2002)2. - ISSN 0165-1587 - p. 285 - 286.
Comparison of sensible heat flux estimates using AVHRR with scintillometer measurements over semi-arid grassland in northwest Mexico
Watts, C.J. ; Chehbouni, A. ; Rodriguez, J.C. ; Kerr, Y.H. ; Hartogensis, O.K. ; Bruin, H.A.R. de - \ 2000
Agricultural and Forest Meteorology 2000 (2000). - ISSN 0168-1923 - p. np 03:C1 - np 03:C1.
The problems associated with the validation of satellite-derived estimates of the surface fluxes are discussed and the possibility of using the large aperture scintillometer is investigated. Simple models are described to derive surface temperature and sensible heat flux from the advanced very high resolution radiometer (AVHRR). Data were collected over an extensive site of semi-arid grassland in northwest Mexico during the summer of 1997 as part of the semi-arid land-surface-atmosphere (SALSA) program. Comparison of surface temperature derived from AVHRR with that derived from a ground-based infrared thermometer showed an RMSE of around 2oC, while estimates of sensible heat flux derived from AVHRR compared well with measurements using either eddy correlation or a large aperture scintillometer.
Estimation of area-averaged sensible heat flux using a large-aperture scintillometer during the Semi-Arid Land-Surface-Atmosphere(SALSA) experiment
Chehbouni, A. ; Kerr, Y.H. ; Watts, C. ; Hartogensis, O. ; Goodrich, D. ; Scott, R. ; Schieldge, J. ; Lee, K. ; Shuttleworth, W.J. ; Dedieu, G. ; Bruin, H.A.R. de - \ 1999
Water Resources Research 35 (1999)8. - ISSN 0043-1397 - p. 2505 - 2511.
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