WIMEK update 2013* 2014* 2015*
Holtslag, A.A.M. ; Leemans, R. ; Siepel, H. ; Spaargaren, G. ; Stams, A.J.M. ; Zee, S.E.A.T.M. van der; Rijnaarts, H.H.M. - \ 2016
Wageningen : Wageningen University
klimatologie - milieuwetenschappen - onderzoeksinstituten - climatology - environmental sciences - research institutes
|Proceedings of the 11th International Precipitation Conference
Leijnse, H. ; Uijlenhoet, R. - \ 2013
Wageningen : KNMI - ISBN 9789461737106 - 233
neerslag - meteorologie - klimatologie - precipitation - meteorology - climatology
Climate Change, Climate Science and Economics
Kooten, G.C. van - \ 2013
Dordrecht : Springer - ISBN 9789400749870 - 465
klimaatverandering - milieueconomie - sociaal beleid - meteorologie - klimatologie - natuur - milieu - geografie - climatic change - environmental economics - social policy - meteorology - climatology - nature - environment - geography
Warmer climates boost cyanobacterial dominance in shallow lakes
Kosten, S. ; Huszar, V.M. ; Bécares, E. ; Costa, S. ; Donk, E. van; Hansson, L. ; Lurling, M.F.L.L.W. - \ 2012
Global Change Biology 18 (2012)1. - ISSN 1354-1013 - p. 118 - 126.
fytoplankton - klimatologie - cyanobacteriën - temperatuur - meren - oppervlaktewaterkwaliteit - phytoplankton - climatology - cyanobacteria - temperature - lakes - surface water quality - fish community structure - trophic state - phytoplankton community - mesocosm experiments - blooms - nitrogen - nutrient - phosphorus - eutrophication
Dominance by cyanobacteria hampers human use of lakes and reservoirs worldwide. Previous studies indicate that excessive nutrient loading and warmer conditions promote dominance by cyanobacteria, but evidence from global scale field data has so far been scarce. Our analysis, based on a study of 143 lakes along a latitudinal transect ranging from subarctic Europe to southern South America, shows that although warmer climates do not result in higher overall phytoplankton biomass, the percentage of the total phytoplankton biovolume attributable to cyanobacteria increases steeply with temperature.
Drought at the global scale in the 2nd part of the 20th century (1963-2001)
Huijgevoort, M.H.J. van; Hazenberg, P. ; Lanen, H.A.J. van; Bertrand, N. ; Clark, D. ; Folwell, S. ; Gosling, S. ; Hanasaki, N. ; Heinke, J. ; Stacke, T. ; Voss, F. - \ 2011
Brussel : European Commission (Technical report / WATCH no. 42) - 40
droogte - hydrologische gegevens - aardoppervlak - modellen - hydrologie - klimatologie - geschiedenis - drought - hydrological data - land surface - models - hydrology - climatology - history
The large impacts of drought on society, economy and environment urge for a thorough investigation. A good knowledge of past drought events is important for both understanding of the processes causing drought, as well as to provide reliability assessments for drought projections for the future. Preferably, the investigation of historic drought events should rely on observations. Unfortunately, for a global scale these detailed observations are often not available. Therefore, the outcome of global hydrological models (GHMs) and off-line land surface models (LSMs) is used to assess droughts. In this study we have investigated to what extent simulated gridded time series from these large-scale models capture historic hydrological drought events. Results of ten different models, both GHMs and LSMs, made available by the WATCH project, were compared. All models are run on a global 0.5 degree grid for the period 1963-2000 with the same meteorological forcing data (WATCH forcing data). To identify hydrological drought events, the monthly aggregated total runoff values were used. Different methods were developed to identify spatio-temporal drought characteristics. General drought characteristics for each grid cell, as for example the average drought duration, were compared. These characteristics show that when comparing absolute values the models give substantially different results, whereas relative values lead to more or less the same drought pattern. Next to the general drought characteristics, some documented major historical drought events (one for each continent) were selected and described in more detail. For each drought event, the simulated drought clusters (spatial events) and their characteristics are given for one month during the event. It can be concluded that most major drought events are captured by all models. However, the spatial extent of the drought events differ substantially between the models. In general the models show a fast reaction to rainfall and therefore also capture drought events caused by large rainfall anomalies. More research is still needed, since here we only looked at a few selected number of documented drought events spread over the globe. To assess more in detail if these large-scale models are able to capture drought, additional quantitative analyses are needed together with a more elaborated comparison against observed drought events.
Simulation of low flows and drought events in WATCH test basins: impact of climate forcing datasets
Huijgevoort, M.H.J. van; Loon, A.F. van; Hanel, M. ; Haddeland, I. ; Horvát, O. ; Koutroulis, A. ; Machlica, A. ; Weedon, G.P. ; Fendeková, M. ; Tsanis, I. ; Lanen, H.A.J. van - \ 2011
2011 : European Commission (Technical report / WATCH no. 44) - 19
geohydrologie - gegevensanalyse - resolutie - aardoppervlak - afvloeiingswater - bodemwater - klimatologie - evaporatie - geohydrology - data analysis - resolution - land surface - runoff water - soil water - climatology - evaporation
The impact of both spatial and temporal resolution on the components of the terrestrial hydrological cycle are investigated using the WATCH forcing dataset (WFD) and the JULES (Joint UK Land Environment Simulator) land surface model. The various spatial resolutions are achieved by degrading the native half degree latitude/longitude resolution WATCH dataset to both one degree and two degrees. The temporal resolutions are created by degrading the native three hourly WATCH forcing dataset to six hourly and using the WATCH interpolator to derive a one hour forcing dataset. There is little difference in the moisture stores of soil water and canopy water in the long term mean from the various resolutions, so the analysis presented is for the changes in evaporation and runoff. The evaporation is further analysed into its various components for the spatial resolution. Results suggest that there is little impact from spatial resolution, but the interpolation method for temporal resolution can have a significant effect on the total mean evaporation/runoff balance.
WIMEK update 2008-2010
Leemans, R. ; Feenstra, J. ; Hoosbeek, M.R. ; Nab, E. ; Dommelen, A. van - \ 2011
Wageningen : Wageningen UR
klimatologie - milieuwetenschappen - onderzoeksinstituten - climatology - environmental sciences - research institutes
Stigter, C.J. - \ 2010
Berlin : Springer - ISBN 9783540746973 - 1100
meteorologie - klimatologie - landbouw - milieubeheer - bosbouw - klimaatverandering - aardwetenschappen - meteorology - climatology - agriculture - environmental management - forestry - climatic change - earth sciences
This compendium first reviews regional operational applications of agrometeorology in the form of case studies of agrometeorological services and information. These services prepare farmers of different income levels for extreme weather and climate events and for the use of weather and climate “windows of opportunity” under conditions of a changing climate. Subsequently wide fields of application are covered such as crops (monocropping and multiple cropping, for which aspects of soils, pests, diseases, water, fertilizers and labour are discussed, in so far as they interact with agrometeorological factors), forestry, agroforestry, livestock, and fisheries. These fields are dealt with in a way that the contents form the bedrock material for establishment, improvement, extension and updating of agrometeorological services and information under these changing conditions. Operational supportive methods are finally reviewed and exemplified through case studies of their applications in the above mentioned fields, in approaches related to actual problem solving in agricultural production. This compendium also wants to create a renaissance in the teaching (that is education/training/ extension) of applied agrometeorology at all levels, closer to the livelihood of farmers and other growers.
Natuur toont klimaatverandering
Vliet, A.J.H. van - \ 2010
Tuin en Landschap 32 (2010)5. - ISSN 0165-3350 - p. 40 - 41.
klimaatverandering - opwarming van de aarde - klimatologie - broeikaseffect - klimaat - volksgezondheid - climatic change - global warming - climatology - greenhouse effect - climate - public health
Het klimaat van Nederland in de afgelopen tien jaar is vergelijkbaar met dat van Lyon in de jaren zeventig en de gevolgen daarvan zijn in de natuur duidelijk te merken. Planten bloeien vroeger, het groeiseizoen duurt langer en de soortenrijkdom van ons land verandert
Game-theoretic analysis of international climate agreements: the design of transfer schemes and the role of technological change
Nagashima, M.N. - \ 2010
Wageningen University. Promotor(en): Ekko van Ierland, co-promotor(en): R.B. Dellink; Hans-Peter Weikard. - [S.l.] : S.n. - ISBN 9789085856078 - 145
klimatologie - klimaatverandering - internationale verdragen - internationale samenwerking - speltheorie - besluitvorming - technologieoverdracht - modellen - opwarming van de aarde - milieubeleid - climatology - climatic change - international agreements - international cooperation - game theory - decision making - technology transfer - models - global warming - environmental policy
Global warming is one of the crucial challenges that the world is facing now. The allocation of
reduction efforts among regions has long been negotiated and it will not be an easy task to achieve a
full cooperation with stringent targets.
The thesis examines the formation of international climate agreements (ICAs) in a game-theoretic
framework. I analyse strategic behaviour of a number of regions to reduce greenhouse gas (GHG)
emissions. Game-theoretic approaches have been widely used to examine an interaction between
countries in the negotiations on climate change, and have emphasised difficulties in designing such a
voluntary agreement. This thesis provides a systematic approach to examine the impacts of designs of
the ICAs on the success of ICAs.
In Chapter 2, I present the basic structure of the STACO-2.1 model, composed of a game-theoretic
framework and applied features, with specifications and calibrations of the functions used in the
model. I analyse the results for (i) the All Singletons coalition structure, (ii) the Grand coalition
structure, and (iii) all stable coalition structures. This case can serve as a suitable reference point for
the analysis of the various mechanisms in the following chapters. The results show that a coalition of
EU15 and Japan is stable. Both regions have an interest in cooperation, because of their higher
marginal benefits from abatement. The results suggest that regions with relatively lower marginal
abatement costs and lower marginal benefits would be worse off when they cooperate as they bear the
largest burden of abatement but obtain the least benefits. This suggests that transfer schemes can be
effective to stabilise larger coalitions.
In Chapter 3, I analyse the impact of pragmatic and optimal transfer schemes on the incentives for
regions to join international climate agreements. With an applied model that comprises twelve world
regions I investigate: (i) a benchmark without transfers, (ii) scenarios with allocation-based rules
where coalition members receive tradable emission permits proportional to initial or future emissions,
(iii) scenarios with outcome-based rules where the coalition surplus is distributed proportional to the
emissions, and (iv) a scenario based on an optimal sharing rule where the coalition surplus is
distributed proportional to outside option payoffs.
I find that when the transfer scheme is poorly designed in the sense that it increases incentives to
free-ride, the best performing stable coalition may be worse than in the case of no transfers. In our
applied setting this occurs for the initial-emissions-based tradable permit system (grandfathering).
Improvements of the initial-emissions-based tradable permit system, such as a tradable permit system
based on the full path of emissions or a surplus sharing scheme, do enhance stability of coalitions. For
the optimal transfer scheme we find that larger coalitions, which include key players such as the
United States and China, can be stable, but no transfer scheme is capable of stabilising the Grand
Coalition. The results show that optimal transfers perform much better than more pragmatic transfer
schemes. Such schemes, however, require detailed insight into the incentive structures of the regions.
Therefore, there is a trade-off between more pragmatic schemes that may be easier to implement but
are hardly effective and optimal transfers which may be hard to achieve in actual negotiations.
In Chapter 4, I explore how different technology spillover mechanisms among regions can
influence the incentives to join and stabilise an international agreement. Several theories on the impact
of technology spillovers are evaluated by simulating a range of alternative specifications: (i) no
spillovers, (ii) internal spillovers, (iii) global spillovers, (iv) coalitional spillovers, and (v) extended
spillovers (all possible technology spillovers).
I find that spillovers are a good instrument to increase the abatement efforts of coalitions and
reduce the associated costs. In our setting, however, they cannot overcome the strong free-rider
incentives that are present in larger coalitions. Therefore, technology spillovers do not substantially
increase the success of international environmental agreements. This conclusion is robust with respect
to the specification of technology spillovers.
In Chapter 5, I relax the assumption of exogenous technological change analysed in the previous
chapters and explore the impacts of induced technological change (ITC) on the stability of an
international climate agreement. To examine the impacts of different specifications of technological
change in reducing abatement costs on regional incentives, three scenarios are investigated: (i) no
technological change (noTC), (ii) exogenous technological change (ExTC), and (iii) induced
technological change (ITC). Technological change is induced by the abatement targets. It reduces
emissions through regional R&D investments, which lowers abatement costs over time. The results
reveal that the set of best-performing stable coalitions and the associated indicator of success hardly
change between the scenario of noTC and ExTC, but ITC does produce a different set of stable
coalitions. Coalitions that are stable in all three scenarios can achieve the highest NPV of payoffs in
the case of ITC. The results indicate that coalition members increase their investments and abatement
substantially when they cooperate in the case of ITC. As a result of increased global abatement, not
only coalition members but also singletons obtain high benefits, which leads to decrease (increase) in
the number of internally (externally) stable coalitions. Therefore, ITC might improve global payoffs,
however, at the same time it tends to increase free-rider incentives due to the public good nature of
global warming. I find that the indicator of success is quite robust with respect to the productivity of
R&D. Furthermore, the number of internally (externally) stable coalitions decreases (increases) with
the value of the productivity of R&D, as free-riding incentives increase. I find that stability is sensitive
with respect to changes of the discount rate. The number of stable coalitions increases with the value
of discount rate. In both cases, the dominating mechanism is that higher productivity of R&D or a
lower discount rate increase the payoffs of regions, and thus increase the gains of cooperation, but also
increase free-rider incentives.
Overall, the main finding of this thesis is that well-designed mechanisms can facilitate successful
formation of partial coalitions, although global cooperation is still hard to achieve. The reason lies in
the public good nature of global warming and regional characteristics of benefits and costs. Following
insights of the current literature on transfer schemes, our systematic analysis supports the fact that an
incentive to join the agreement is highly sensitive to the design of transfers. For different designs of
transfer schemes, there is a trade-off between feasibility and effectiveness. Allocation-based transfer
schemes are easier to implement than an optimal transfer scheme which can achieve more successful
coalition formation in the context of global payoffs and CO2 emissions.
The role of technological change has received significant attentions to reduce a significant amount
of emissions. Two types of sources of technological change are investigated in the thesis: (i)
technology spillovers and (ii) R&D investment. If technology spillovers are treated as private goods, a
country with higher abatement technology can be an attractive partner for other countries to cooperate
with, as cooperation on abatement will lead to reduction in abatement costs without paying for
technology improvement. Within the context of assumptions used here, quantitative results suggest
that the spillovers between cooperating regions may not be effective enough to overcome the freeriding
incentives for non-cooperative countries, as large emission reduction by cooperating countries
will bring large benefits also to non-cooperating countries.
In the case of induced technological change, regional R&D investments improve the stock of
knowledge which leads to low abatement costs. When cooperating with other regions, signatories can
obtain higher payoffs than in All Singletons, which is driven by increased investment after cooperation
on abatement. ITC plays a significant role in increasing global payoffs, however, it also increases freerider
incentives as non-signatories also benefit from a large reduction made by signatories. As long as
R&D investments increase payoffs under cooperation on abatement and the gains from cooperation
are large, the difference in the source of technological change will not provide any significant
differences in terms of improvement in the success of a climate agreement.
The Kyoto Protocol was the first significant step that provided stimulus for search for successful
international cooperation on climate change policies, although there are issues to be improved. Now,
negotiation on the post Kyoto framework has been taking place with an aim of large cooperation on
tackling climate change among countries. Flexible measures which lead to a win-win cooperation for
the countries involved will continue to play a crucial role in achieving a successful cooperation and the
search for well-designed mechanisms will be further pursued.
A Climatology of Nocturnal Low-Level Jets at Cabauw
Baas, P. ; Bosveld, F.C. ; Baltink, H.K. ; Holtslag, A.A.M. - \ 2009
Journal of Applied Meteorology and Climatology 48 (2009)8. - ISSN 1558-8424 - p. 1627 - 1642.
windsnelheid - grenslaagmeteorologie - klimatologie - utrecht - wind speed - boundary-layer meteorology - climatology - utrecht - atmospheric boundary-layer - southern great-plains - sloping terrain - kinetic-energy - united-states - wind - model - turbulence - intermittent - land
A climatology of nocturnal low-level jets (LLJs) is presented for the topographically flat measurement site at Cabauw, the Netherlands. LLJ characteristics are derived from a 7-yr half-hourly database of wind speed profiles, obtained from the 200-m mast and a wind profiler. Many LLJs at Cabauw originate from an inertial oscillation, which develops after sunset in a layer decoupled from the surface by stable stratification. The data are classified to different types of stable boundary layers by using the geostrophic wind speed and the isothermal net radiative cooling as classification parameters. For each of these classes, LLJ characteristics like frequency of occurrence, height above ground level, and the turning of the wind vector across the boundary layer are determined. It is found that LLJs occur in about 20% of the nights, are typically situated at 140-260 m above ground level, and have a speed of 6-10 m s(-1). Development of a substantial LLJ is most likely to occur for moderate geostrophic forcing and a high radiative cooling. A comparison with the 40-yr ECMWF Re-Analysis (ERA-40) is added to illustrate how the results can be used to evaluate the performance of atmospheric models
Conditionering van watertemperatuur in buitenvijvers voor aquacultuur
Jacobs, C.M.J. ; Maat, H.W. ter; Elbers, J.A. ; Stuyt, L.C.P.M. - \ 2009
Wageningen : Alterra - 91
aquacultuur - vijverteelt - plassen - watertemperatuur - klimatologie - aquaculture - pond culture - ponds - water temperature - climatology
Frequentie, duur en hevigheid van temperatuurextremen in buitenvijvers voor de aquacultuur in Zeeland zijn gekwantificeerd via een model dat de invloed van het weer op de watertemperatuur betrouwbaar simuleert.
Climatology of extreme rainfall from rain gauges and weather radar
Overeem, A. - \ 2009
Wageningen University. Promotor(en): Remko Uijlenhoet, co-promotor(en): I. Holleman; T.A. Buishand. - [S.l. : S.n. - ISBN 9789085855170 - 131
neerslag - klimatologie - klimaatfactoren - weersgegevens - meteorologische waarnemingen - regenmeters - inundatie - overstromingen - weersvoorspelling - waterbouwkunde - hydraulische systemen - nederland - precipitation - climatology - climatic factors - weather data - meteorological observations - rain gauges - flooding - floods - weather forecasting - hydraulic engineering - hydraulic structures - netherlands
Extreme neerslaggebeurtenissen hebben een grote invloed op de maatschappij en kunnen leiden tot materi¨ele schade en slachtoffers. Daarom is een betrouwbare klimatologie van extreme neerslag belangrijk, bijvoorbeeld voor het ontwerp van afvoersystemen. Een dergelijke klimatologie kan worden verkregen door jaarmaxima te selecteren uit lange neerslagreeksen. Vervolgens wordt een kansverdeling aangepast aan de geselecteerde jaarmaxima, zodat neerslaghoeveelheden kunnen worden geschat voor een gekozen herhalingstijd, die langer kan zijn dan de neerslagreeks. In dit proefschrift worden jaarmaxima gemodelleerd met de Gegeneraliseerde ExtremeWaarden (GEV) verdeling.
News in Climate Science and Exploring Boundaries: A Policy brief on developments since the IPCC AR4 report in 2007
Meyer, L.A. ; Leemans, R. ; Kuikman, P.J. ; Hutjes, R.W.A. ; Swart, R. ; Verhagen, A. ; Vliet, A.J.H. van; Marinova, N.A. - \ 2009
Bilthoven : PBL, KNMI, WUR (PBL publication 500114013) - 51
klimaat - klimatologie - klimaatverandering - monitoring - climate - climatology - climatic change - monitoring
The IPCC Fourth Assessment Report of 2007 (AR4), today, still offers a solid scientific base for climate policy-making. However, there are risks that climate change may happen faster - or may have more severe impacts – than expected. Therefore, it is recommended to increase climate monitoring efforts, and investigate policy response options addressing these risks.
Long-term microclimate experience in urban public spaces in The Netherlands
Lenzholzer, S. - \ 2009
In: 5th Japanese-German Meeting on Urban Climatology, Freiburg, Germany, 5-11 October 2008. - Freiburg, Germany : Albert-Ludwigs-University - p. 221 - 229.
klimatologie - stedelijke gebieden - stadsomgeving - klimaatverandering - stedelijke planning - climatology - urban areas - urban environment - climatic change - urban planning
Cloud physical properties retrieval for climate studies using SEVIRI and AVHRR data = Afleiden van fysische eigenschappen van wolken voor klimaatstudies met behulp van SEVIRI en AVHRR gegevens
Roebeling, R.A. - \ 2008
Wageningen University. Promotor(en): Bert Holtslag, co-promotor(en): A.J. Feijt; P. Stammes. - [S.l.] : S.n. - ISBN 9789085048923 - 158
wolken - fysische eigenschappen - optische eigenschappen - meteorologie - meteorologische waarnemingen - satellieten - klimatologie - clouds - physical properties - optical properties - meteorology - meteorological observations - satellites - climatology
Accurate and long term information on the physical properties of clouds is required to increase our understanding on the role of clouds in the current climate system, and to better predict the behavior of clouds in a changing climate. This thesis investigates if retrievals of cloud physical properties from satellite imagers can be used to prepare time series of these properties for monitoring climate change, and to evaluate parameterizations of cloud processes in weather and climate prediction models.
An algorithm for retrieval of Cloud Physical Properties (CPP) from visible and near-infrared reflectances of the AVHRR instrument onboard NOAA and the SEVIRI instrument onboard METEOSAT is presented. This algorithm retrieves cloud optical thickness, effective radius, and liquid water path, whereas a cloud model is used to simulate cloud geometrical thickness and droplet number concentration. Due to the large differences found between the reflectances from the different instruments (up to 25%), a recalibration procedure is developed that successfully reduces the retrieval differences to less than 5%. The uniqueness of the SEVIRI cloud property retrievals is in its unprecedented sampling frequency (15 minutes) that ensures the statistical significance of the dataset. One year of cloud liquid water path retrievals is validated against simultaneous Cloudnet microwave radiometer observations over Europe. The results show that during summer the agreement is very good while during winter an overestimation of about 20% is observed. Possible reason for this overestimation is the plane-parallel assumption in the CPP algorithm used to simulate real clouds. For single-layer stratocumulus days, a sub-adiabatic cloud model is used to obtain cloud geometrical thickness and cloud droplet number concentration. During these days good agreement is found between geometrical thickness simulations and Cloudnet lidar and radar observations, and cloud liquid water path retrievals and Cloudnet microwave radiometer observations. The simulated droplet concentration is found to vary independently from liquid water path and the geometrical thickness, which suggests possible interactions between aerosols and clouds. This shows potential in our dataset for studies of the indirect aerosol effect.
The SEVIRI dataset of cloud property retrievals is used to evaluate the Regional Climate Model (RACMO) over Europe during a six-month period. The results show that RACMO represents the spatial variations of cloud amount and cloud liquid water path realistically, but underpredicts cloud amount by 20% and overpredicts liquid water path by 30%. Examination of the diurnal cycle shows that the RACMO maximum liquid water path occurs two hours earlier than that observed by SEVIRI, while the RACMO maximum cloud amount agrees reasonably well with SEVIRI’s amount. The largest differences in the diurnal cycle between RACMO and SEVIRI are found in regions of alternating stratiform and convective regimes where RACMO has difficulty representing the transition between these regimes. The SEVIRI dataset of cloud physical properties proves to be a powerful tool for evaluating parameterizations of cloud and precipitation processes in weather and climate prediction models, and thus helps increase the confidence in these models.
Parameter sensitivity of climate models and climate driven ecological systems
Moolenaar, H.E. - \ 2006
Wageningen University. Promotor(en): Johan Grasman, co-promotor(en): F.M. Selten. - [S.l. ] : S.n. - ISBN 9789085044529 - 133
klimatologie - klimaat - ecologie - wiskundige modellen - betrouwbaarheid - gevoeligheid - verstoring - climatology - climate - ecology - mathematical models - reliability - sensitivity - disturbance
Uncertainty in the outcome of numerical models of physical and biological processes, such as the climate and ecological systems, is widely recognized. One contributing factor is uncertainty in model parameters. Because of this uncertainty, a range of model outcomes is usually given. This might obstruct policy making for topics such as the reduction of climate change and nature conservation management. Part of the estimation of uncertainty is a parameter sensitivity analysis. It is important to verify how small changes in parameters can affect the model outcome. Especially extreme deviations are of interest to gain an understanding of the variability of the result. We therefore need to identify the parameter perturbations the model is most sensitive to. Since the atmospheric circulation behaves as a chaotic system quantities that characterise the climate have to be computed froman integrationover a large time interval. Perturbing a large set of parameters to analyse the variability of the outcome would require an enormous computing time. It would therefore be advantageous to select effective parameters a priori. In this thesis a method is described that selects these parameters in an efficient way. The short term behaviour of a nonlinear model is used to select parameter perturbations that are likely to cause a large change in the dynamics of the long term behaviour of the model. A short section of a reference orbit is calculated. Next the error growth from the parameter perturbation can be computed with the use of tangent linear equations. The adjoint of the model acts as a backward integration and can then be used to calculate the parameter perturbation that causes the largest error growth over this interval. This perturbation vector is more likely to be also an effective parameter perturbation for a long time integration simulating the climate than a randomly chosen one. More precisely, it turns out that not exactly at a point of the chaotic attractor with a large error growth but just a moment later when this growth has fallen back has to be selected. These points are found by analysing a succession of many short time intervals over each of which the tangent linear approximation holds.We apply this adjoint method to two climate models; the Lorenz 63 model and the atmospheric T21QG model, and a climate driven metapopulation model; the Rosenzweig-McArthur model coupled to the Lorenz 84 model. The success rate of drawing a parameter perturbation causing a large change should for the adjoint method be considerably higher than for a random search method. Climate change is defined in terms of changes in the occurrence and strength of different preferred atmospheric circulation patterns. In the contextof metapopulationmodels and conservation management, the goal is to find perturbations in the biological parameters that lower the risk of extinction of herbivore subpopulations. It is found that in the simple models, where only 5 parameters are varied (Lorenz 63 and the Rosenzweig-McArthur model forced by Lorenz 84), the adjoint method has a significantly higher success rate in drawing effective parameter perturbations than a random search method does. In the more complex T21QG model drawing an effective parameter perturbation appears to be a much more strenuous task due to the large number of 1449 parameters that are varied. However, although hampered by this large parameter set and the required long time integrationof thissystem with many degrees of freedom, the adjoint method comes much closer to selecting the parameter perturbation causing the largest climate change than the random method
Preface: GEWEX Atmospheric Boundary-layer Study (GABLS) on Stable Boundary Layers
Holtslag, A.A.M. - \ 2006
Boundary-Layer Meteorology 118 (2006)2. - ISSN 0006-8314 - p. 243 - 246.
atmosferische grenslaag - klimatologie - modellen - atmospheric boundary-layer - climatology - models - surfaces - climate - fluxes - land
The Global Energy and Water Cycle Experiment (GEWEX) is a program initiated by the World Climate Research Programme (WCRP) to observe, understand and model the hydrological cycle and the related energy fluxes in the atmosphere, at the land surface and in the upper oceans. Consequently the atmospheric boundary layer is an important aspect of the energy and water cycle, which has become crucially important in this new age of coupled atmosphere-land surface-ocean modelling. As such, in 2001, the GEWEX Atmospheric Boundary-layer Study (GABLS) was established. The overall objective of GABLS is to improve the understanding and the representation of the atmospheric boundary layer in regional and large-scale climate models. Such activity is important in itself and also very relevant for other activities in GEWEX, and more generally for the activities within WCRP and the International Geosphere-Biosphere Program (IGBP).
Climate changes spatial planning : knowledge project plan
Kabat, P. ; Vellinga, P. ; Komen, G. ; Metz, B. ; Turkenburg, W. ; Bruggink, J. ; Rotmans, J. ; Marks, J. ; Werners, S.E. ; Veraart, J.A. ; Noord, H. van; Ritt-Fischer, M.R. ; Aerts, J. ; Hutjes, R.W.A. ; Lasage, R. ; Leemans, R. ; Ierland, E.C. van - \ 2003
S.n. - 78
klimatologie - klimaatverandering - ruimtelijke ordening - projecten - beleid - nederland - europa - climatology - climatic change - physical planning - projects - policy - netherlands - europe
Uitgave in het kader van Programma Klimaat voor Ruimte
The sustainability of carbon sinks in forests; studying the sensitivity of forest carbon sinks in the Netherlands, Europe and the Amazon to climate and management
Kruijt, B. ; Kramer, K. ; Wyngaert, I.J.J. van den; Groen, R. ; Elbers, J.A. ; Jans, W.W.P. - \ 2003
Wageningen : Alterra (Alterra-rapport 750) - 62
bossen - bodemeigenschappen - kooldioxide - koolstofcyclus - bodemchemie - modellen - klimatologie - bosbedrijfsvoering - klimaatverandering - europa - brazilië - forests - soil properties - carbon dioxide - carbon cycle - soil chemistry - models - climatology - forest management - climatic change - europe - brazil
The aim of this study was to assess the sustainability of carbon sinks in managed or unmanaged forests in Europe and Amazonia. First, the functioning and seasonal variability of the carbon sink strength in forest ecosystems was analysed in relation toclimate variability. To this end, existing global data sets of ecosystem fluxes measured by eddy correlation were analysed. A simple, comprehensive empirical model was derived to represent these flux variabilities. Furthermore, new soil respiration measurements were initiated in the Netherlands and Amazonia and their usefulness to understand the uptake and emission components of carbon exchange was analysed. Then, two long-term forest dynamics models were parameterized (FORSPACE and CENTURY) for Dutch Pinus and Fagus forests, to study the development of forest carbon stocks over a century under different management and climate scenarios. Finally, using the empirical model as well as the long-term models, scenario predictions were made. It turns out that uptake rates are expected to decrease in a climate with higher temperatures, but that storage capacity for carbon can be expected to be slightly enhanced, especially if also the management intensity is carefully tuned down.