The Integrated Economic-Environmental Modeling (IEEM) Platform: IEEM Platform Technical Guides: User Guide for the IEEM-enhanced Land Use Land Cover Change Model Dyna-CLUE

The Conversion of Land Use and its Effects modeling framework (CLUE) was developed to simulate land use change using empirically quantified relations between land use and its driving factors in combination with dynamic modeling of competition between land use types. Being one of the most widely used spatial land use models, CLUE has been applied all over the world on different scales. In this document, we demonstrate how the model can be used to develop a multi-regional application. This means, that instead of developing numerous individual models, the user only prepares one CLUE model application, which then allocates land use change across different regions. This facilitates integration with the Integrated Economic-Environmental Modeling (IEEM) Platform for subnational assessments and increases the efficiency of the IEEM and Ecosystem Services Modeling (IEEMESM) workflow. Multi-regional modelling is particularly useful in larger and diverse countries, where we can expect different spatial distributions in land use changes in different regions: regions of different levels of achieved socio-economic development, regions with different topographies (flat vs. mountainous), or different climatic regions (dry vs humid) within a same country. Accounting for such regional differences also facilitates developing ecosystem services models that consider region specific biophysical characteristics. This manual, and the data that is provided with it, demonstrates multi-regional land use change modeling using the country of Colombia as an example. The user will learn how to prepare the data for the model application, and how the multi-regional run differs from a single-region simulation.

Regional winds over the Iberian Peninsula with COSMO-REA6 high resolution regional reanalysis: cierzo, levante and poniente

<p>Regional winds are caused by small-scale pressure differences in a way that important air flows can arise in a very small and specific region. Sometimes an orographic feature, such as a channel like the Ebro Valley or the Strait of Gibraltar, lead the wind, due to mass conservation, to acquire a certain specific range of directions and considerable speed. In the regions where they are observed, the wind is of great importance not only for the climatology and meteorology of these areas but also for their culture and identity. However, it is difficult to analyze them using the most common reanalysis products, since their spatial resolutions are not high enough to properly describe the orographic characteristics that lead to the regional winds in specific locations. Here, we will explore the application of the COSMO-REA6 high resolution reanalysis system for the assessment of the main regional winds in the Iberian Peninsula: the cierzo wind in the Ebro Valley and the levante and poniente winds in the Strait of Gibraltar, for the 2000-2018 period. COSMO-REA6 uses a spatial resolution of 6 km (0.055º), which is much larger than previous reanalysis and regional modelling databases, so it can better capture the orography of the areas and therefore the regional winds we intend to study. The cierzo, levante and poniente winds are very relevant in the Iberian Peninsula due to their intensity and their frequency. Defined with a 5 m/s threshold for each hour, and their specific direction range, around 95, 150 and 110 wind days per year are obtained, respectively. Their study may also be important for other reasons, such as the production of renewable energy in these areas. First, we conduct a preliminary assessment of wind speed and direction with hourly data from weather stations, which have been obtained from the HadISD global sub-daily dataset. Then, we compare data from stations with COSMO-REA6 reanalysis in each location and produce a spatial description of the reanalysis in the Peninsula. We also study the atmospheric patterns associated with the regional winds characterized above. Due to the few studies that have been carried out on regional winds in the Iberian Peninsula, these results can be of great interest for various fields, such as meteorology, climatology and the generation of renewable energy.</p>

Impact of Ragweed Pollen Daily Release Intensity on Long-Range Transport in Western Europe

This study is dedicated to improving the daily release of ragweed pollen emission in the context of deterministic regional modelling for analysis and forecast. First, correlations are calculated between daily modelled meteorological variables (wind speed, temperature, humidity, precipitation, surface fluxes) and daily pollen counts at nine stations in Hungary, Croatia and France between 2005 and 2011. The 2 m temperature is the most correlated parameter, followed by convective velocity and incoming shortwave radiation, while precipitation rate and 2 m specific humidity act as limiting factors. Using these results, a ragweed pollen daily release formulation is proposed. This formulation is implemented in the CHIMERE chemistry-transport model and tested during the whole year of 2010. Results are compared to observations, and it is shown that the new formulation provides a more realistic day-to-day variability: the spatio-temporal correlation between surface measurements and modelled concentrations is 0.77, greater than two other known emission schemes.

Spatio-temporal effects of vegetated windbreaks on wind erosion and microclimate as basis for model development

<p>Wind erosion of arable soil is considered a risk factor for Austrian fields, but direct measurements of soil loss are not available until now. Despite this uncertainty, vegetated windbreaks have been established to minimize adverse wind impacts on arable land. The study addresses these questions: i) How relevant is wind erosion as a factor of soil degradation? ii) How important is the protective effect of vegetated windbreaks? iii) Are systematic patterns of spatial and temporal variability of wind erosion rates detectable in response to weather conditions? </p><p>Two experimental fields adjacent to windbreaks were equipped with sediment traps, soil moisture sensors, and meteorological measurement equipment for microclimatic patterns. Sediment traps were arranged in high spatial resolution from next to the windbreak to a distance of ten times the windbreak height. Beginning in January 2020, the amount of trapped sediment was analyzed every three weeks. The highest wind erosion rates on bare soil were observed in June and July. For unprotected fields with bare soil, upscaled annual erosion rates were as high as 0.8 tons per hectare, and sediment trapped increased in a linear fashion with distance from the windbreak. Soil water content near the surface (5 cm depth) was three percent higher at a distance of two times the height of the windbreak than at a distance of six times the height. For the same respective distances from the windbreak, we observed 29 days of soil water contents below the wilting point compared with 60 days.</p><p>The preliminary outcomes confirmed the expected effects of windbreaks on soil erosion and microclimate in agricultural fields. Prospective results from multiple vegetation periods will be used in an upscaling approach to gain informations for the whole basin. That is meant to be done by a combination with a soil wind erosion model which was so far used for regional modelling of wind erosion susceptibility.</p>

Assessing tide correction under altimetry tracks: an innovative validation methodology using USV (Unmanned Surface Vehicle) in-situ measurements

<p>Satellite altimetry recently reached an unprecedented level of global coverage with 7 missions flying simultaneously. While altimeters have been originally designed for open ocean and have improved our understanding of the large-scale ocean dynamic, the exploitation of coastal altimetry data remains a challenge that mobilizes a large effort in the scientific community. The future SWOT mission will solve this issue and certainly revolutionize our view of the coastal waters by<strong> </strong>mapping SSH with an unprecedented resolution.</p><p>One challenging aspect of coastal altimetry is the lack of accuracy in some geophysical corrections, which are critical to derive accurate sea-surface height anomalies (SSHA) near the coast. Especially, uncertainties in ocean tides is still an issue for the exploitation of altimetry in nearshore regions. Global tide models are usually used in most altimetry products. Despite their considerable progress in the last decade, their accuracy tends to decrease near the coast (Lyard, F. et Al., 2020).</p><p>Difficulties encountered in modelling the coastal tide are mainly due to its non-linear behaviour caused by changes in depth, shoreline interactions or varying bottom drag as it propagates onto shallower waters. The distortion of tidal propagation can thus be represented as additional tidal waves, which reflect overtides compound tides. These interactions are numerous and a great number of constituents have to be considered in order to reproduce accurately the tidal signal in shallow regions. Consequently, efforts in developing regional modelling of coastal areas are encouraged, as well as the consideration of ocean/shelf/land as a modelling continuum, for the preparation and exploitation of the future SWOT mission (Ayoub, N. et Al., 2015).</p><p>Moreover, these shallow-water waves exhibit smaller wavelengths than major astronomical ones, and there is a critical need for observations with short space and time scales to appreciate their spatial variability. While tide models are classically validated against tide-gauges confined to the coast, new opportunities are emerging with the development of kinematic GNSS systems. Chupin et Al. (2020), have demonstrated the ability of the Cyclopée system (a combination of a GNSS antenna and an acoustic altimeter) mounted on an USV to map sea surface height in motion. At a fixed point, the Cyclopée system provides similar accuracy than the best tide-gauge systems (and is therefore a way to propagate tide gauges measurements under satellites tracks).</p><p>Through a methodology based on crossover measurements; we demonstrate in this study the potential of the USV PAMELi, developed at the University of La Rochelle, for assessing tide corrections under altimetry tracks, in the scope of future coastal altimetry applications (e.g. storm surge or wave setup). For this purpose, the Pertuis Charentais area (France) is addressed as a modelling case study with a new regional barotropic configuration based on SCHISM model (Zhang, J. et al., 2016). After being compared against coastal tide-gauges, our SCHISM model as well as other available global solutions are assessed though this methodology applied under the pass 216 of Sentinel-3A.</p>

How strongly are mean and extreme precipitation coupled?

<p>Changes in mean and extreme precipitation are among the most important consequences of climate change. Here we examine the relationship between the mean and three different measures of extreme precipitation over the Australian continent, from a regional climate projection ensemble. We show that model uncertainty in mean and extreme precipitation are tightly coupled for both the present-day climate and future changes. On the continental scale the differences in mean precipitation explain 80-99% of the variance in the extremes. We also find that in most regions except along the coasts, precipitation statistics projected by regional modelling system (RCM) are highly predictable from the mean precipitation of the global model (GCM) providing the boundary conditions. In coastal regions RCMs are more accurate than GCMs and they also have more impact on present-day statistics, however, this impact disappears for future changes, suggesting that improved present-day accuracy will not carry over to future changes.</p>

Limits of reproducibility and hydrodynamic noise in atmospheric regional modelling

Reproducibility of research results is a fundamental quality criterion in science; thus, computer architecture effects on simulation results must be determined. Here, we investigate whether an ensemble of runs of a regional climate model with the same code on different computer platforms generates the same sequences of similar and dissimilar weather streams when noise is seeded using different initial states of the atmosphere. Both ensembles were produced using a regional climate model named COSMO-CLM5.0 model with ERA-Interim forcing. Divergent phase timing was dependent on the dynamic state of the atmosphere and was not affected by noise seeded by changing computers or initial model state variations. Bitwise reproducibility of numerical results is possible with such models only if everything is fixed (i.e., computer, compiler, chosen options, boundary values, and initial conditions) and the order of mathematical operations is unchanged between program runs; otherwise, at best, statistically identical simulation results can be expected.

Understanding the development of systematic errors in the Asian Summer Monsoon

Despite the importance of monsoon rainfall to over half of the world’s population, many of the current generation of climate models struggle to capture some of the major features of the various monsoon systems. Studies of the development of errors in several tropical regions have shown that they start to develop very quickly, within the first few days of a model simulation, and can then persist to climate timescales. Understanding the sources of such errors requires the combination of various modelling techniques and sensitivity experiments of varying complexity. Here, we demonstrate how such analysis can shed light on the way in which monsoon errors develop, their local and remote drivers and feedbacks. We make use of the seamless modelling approach adopted by the Met Office, whereby different applications of the Met Office Unified Model (MetUM) use essentially the same model configuration (dynamical core and physical parametrisations) across a range of spatial and temporal scales. Using the Asian Summer Monsoon as an example, we show that error patterns in circulation and rainfall over the East Asia Summer Monsoon (EASM) region in the MetUM are similar between multi-decadal climate simulations and seasonal hindcasts initialised in spring. Analysis of the development of these errors on both short-range and seasonal timescales following model initialisation suggests that both the Maritime Continent and the oceans around the Philippines play a role in the development of EASM errors, with the Indian summer monsoon region providing an additional contribution. Regional modelling with various lateral boundary locations helps to separate local and remote contributions to the errors, while regional relaxation experiments shed light on the influence of errors developing within particular areas on the region as a whole.

Measurement and modelling of the dynamics of NH₃ surface-atmosphere exchange over the Amazonian rainforest

Local and regional modelling of NH3 surface exchange is required to quantify nitrogen deposition to, and emissions from, the biosphere. However, measurements and model parameterisations for many remote ecosystems – such as tropical rainforest – remain sparse. Using one month of hourly measurements of NH3 fluxes and meteorological parameters over a remote Amazon rainforest site (Amazon Tall Tower Observatory, ATTO), six model parameterisations based on a bi-directional, single-layer, canopy compensation point resistance model were developed to simulate observations of NH3 surface exchange. Canopy resistance was linked to either relative humidity at the canopy level (RHz′0), vapour pressure deficit, or a parameter value based on leaf wetness measurements. The ratio of apoplastic NH4+ to H+ concentration, Γs, during this campaign was inferred to be 38.5 ± 15.8. The parameterisation that reproduced the observed net exchange of NH3 most accurately was the model that used a cuticular resistance (Rw) parameterisation based on leaf wetness measurements and a value of Γs = 50 (Pearson correlation r = 0.71). Conversely, the model that performed the worst at replicating measured NH3 fluxes used an Rw value modelled using (RHz′0) and the inferred value of Γs = 38.5 (r = 0.45). The results indicate that a single layer, canopy compensation point model is appropriate for simulating NH3 fluxes from tropical rainforest during the Amazonian dry season, and confirmed that a direct measurement of (a non-binary) leaf wetness parameter improves the ability to estimate Rw. Current inferential methods for determining Γs were noted as having difficulties in the humid conditions present at a rainforest site.