DYPTOP: a cost-efficient TOPMODEL implementation to simulate sub-grid spatio-temporal dynamics of global wetlands and peatlands

Simulating the spatio-temporal dynamics of inundation is key to understanding the role of wetlands under past and future climate change. Earlier modelling studies have mostly relied on fixed prescribed peatland maps and inundation time series of limited temporal coverage. Here, we describe and assess the the Dynamical Peatland Model Based on TOPMODEL (DYPTOP), which predicts the extent of inundation based on a computationally efficient TOPMODEL implementation. This approach rests on an empirical, grid-cell-specific relationship between the mean soil water balance and the flooded area. DYPTOP combines the simulated inundation extent and its temporal persistency with criteria for the ecosystem water balance and the modelled peatland-specific soil carbon balance to predict the global distribution of peatlands. We apply DYPTOP in combination with the LPX-Bern DGVM and benchmark the global-scale distribution, extent, and seasonality of inundation against satellite data. DYPTOP successfully predicts the spatial distribution and extent of wetlands and major boreal and tropical peatland complexes and reveals the governing limitations to peatland occurrence across the globe. Peatlands covering large boreal lowlands are reproduced only when accounting for a positive feedback induced by the enhanced mean soil water holding capacity in peatland-dominated regions. DYPTOP is designed to minimize input data requirements, optimizes computational efficiency and allows for a modular adoption in Earth system models.

Sensitivity of the WRF model to PBL parametrisations and nesting techniques: evaluation of wind storms over complex terrain

Simulating surface wind over complex terrain is a challenge in regional climate modelling. Therefore, this study aims at identifying a set-up of the Weather Research and Forecasting Model (WRF) model that minimises system- atic errors of surface winds in hindcast simulations. Major factors of the model configuration are tested to find a suitable set-up: the horizontal resolution, the planetary boundary layer (PBL) parameterisation scheme and the way the WRF is nested to the driving data set. Hence, a number of sensitivity simulations at a spatial resolution of 2 km are carried out and compared to observations. Given the importance of wind storms, the analysis is based on case studies of 24 historical wind storms that caused great economic damage in Switzerland. Each of these events is downscaled using eight different model set-ups, but sharing the same driving data set. The results show that the lack of representation of the unresolved topography leads to a general overestimation of wind speed in WRF. However, this bias can be substantially reduced by using a PBL scheme that explicitly considers the effects of non-resolved topography, which also improves the spatial structure of wind speed over Switzerland. The wind direction, although generally well reproduced, is not very sensitive to the PBL scheme. Further sensitivity tests include four types of nesting methods: nesting only at the boundaries of the outermost domain, analysis nudging, spectral nudging, and the so-called re-forecast method, where the simulation is frequently restarted. These simulations show that restricting the freedom of the model to develop large-scale disturbances slightly increases the temporal agreement with the observations, at the same time that it further reduces the overestimation of wind speed, especially for maximum wind peaks. The model performance is also evaluated in the outermost domains, where the resolution is coarser. The results demonstrate the important role of horizontal resolution, where the step from 6 to 2 km significantly improves model performance. In summary, the combination of a grid size of 2 km, the non-local PBL scheme modified to explicitly account for non-resolved orography, as well as analysis or spectral nudging, is a superior combination when dynamical downscaling is aimed at reproducing real wind fields.

MEMLS3&a: Microwave Emission Model of Layered Snowpacks adapted to include backscattering

The Microwave Emission Model of Layered Snowpacks (MEMLS) was originally developed for microwave emissions of snowpacks in the frequency range 5–100 GHz. It is based on six-flux theory to describe radiative transfer in snow including absorption, multiple volume scattering, radiation trapping due to internal reflection and a combination of coherent and incoherent superposition of reflections between horizontal layer interfaces. Here we introduce MEMLS3&a, an extension of MEMLS, which includes a backscatter model for active microwave remote sensing of snow. The reflectivity is decomposed into diffuse and specular components. Slight undulations of the snow surface are taken into account. The treatment of like- and cross-polarization is accomplished by an empirical splitting parameter q. MEMLS3&a (as well as MEMLS) is set up in a way that snow input parameters can be derived by objective measurement methods which avoid fitting procedures of the scattering efficiency of snow, required by several other models. For the validation of the model we have used a combination of active and passive measurements from the NoSREx (Nordic Snow Radar Experiment) campaign in Sodankylä, Finland. We find a reasonable agreement between the measurements and simulations, subject to uncertainties in hitherto unmeasured input parameters of the backscatter model. The model is written in Matlab and the code is publicly available for download through the following website: http://www.iapmw.unibe.ch/research/projects/snowtools/memls.html.

Model results of ocean physical field of the reference state and the targets in NetCDF format

In a feasibility study, the potential of proxy data for the temperature and salinity during the Last Glacial Maximum (LGM, about 19 000 to 23 000 years before present) in constraining the strength of the Atlantic meridional overturning circulation (AMOC) with a general ocean circulation model was explored. The proxy data were simulated by drawing data from four different model simulations at the ocean sediment core locations of the Multiproxy Approach for the Reconstruction of the Glacial Ocean surface (MARGO) project, and perturbing these data with realistic noise estimates. The results suggest that our method has the potential to provide estimates of the past strength of the AMOC even from sparse data, but in general, paleo-sea-surface temperature data without additional prior knowledge about the ocean state during the LGM is not adequate to constrain the model. On the one hand, additional data in the deep-ocean and salinity data are shown to be highly important in estimating the LGM circulation. On the other hand, increasing the amount of surface data alone does not appear to be enough for better estimates. Finally, better initial guesses to start the state estimation procedure would greatly improve the performance of the method. Indeed, with a sufficiently good first guess, just the sea-surface temperature data from the MARGO project promise to be sufficient for reliable estimates of the strength of the AMOC.

El cambio en la designación general de material (DGM) de las AACR a las RDA : Definición de los atributos tipo de contenido, tipo de medio y tipo de soporte

Se aborda el estudio de los atributos tipo de contenido, tipo de medio y tipo de soporte definidos por el código de catalogación Resource Description and Access (RDA) para solucionar los problemas que presentaba la lista de términos utilizadas para registrar la designación general de material (DGM) en las Anglo American Cataloging Rules (AACR). Los términos eran ambiguos combinando aspectos referidos al contenido y clase de material del recurso. Se parte de una exhaustiva revisión bibliográfica y del estudio de los documentos que se generaron en el proceso de elaboración del nuevo código. Se menciona el trabajo conjunto entre el Joint Steering Committee (JSC) y el estándar ONIX para el establecimiento de criterios que permitieron definir estos tres atributos, así como el aporte del modelo FRBR en la definición de los mismos. Se presentan ejemplos de registros bibliográficos donde se utilizan estos tres atributos en formato MARC21, ISBD consolidada a partir de la definición del área 0 y en el esquema de metadatos Dublin Core. Se finaliza destacando la necesidad de continuar con investigaciones que permitan concluir sobre la adecuación de estos tres atributos a las necesidades de los catalogadores, usuarios y a la realidad tecnológica

El cambio en la designación general de material (DGM) de las AACR a las RDA : Definición de los atributos tipo de contenido, tipo de medio y tipo de soporte

Se aborda el estudio de los atributos tipo de contenido, tipo de medio y tipo de soporte definidos por el código de catalogación Resource Description and Access (RDA) para solucionar los problemas que presentaba la lista de términos utilizadas para registrar la designación general de material (DGM) en las Anglo American Cataloging Rules (AACR). Los términos eran ambiguos combinando aspectos referidos al contenido y clase de material del recurso. Se parte de una exhaustiva revisión bibliográfica y del estudio de los documentos que se generaron en el proceso de elaboración del nuevo código. Se menciona el trabajo conjunto entre el Joint Steering Committee (JSC) y el estándar ONIX para el establecimiento de criterios que permitieron definir estos tres atributos, así como el aporte del modelo FRBR en la definición de los mismos. Se presentan ejemplos de registros bibliográficos donde se utilizan estos tres atributos en formato MARC21, ISBD consolidada a partir de la definición del área 0 y en el esquema de metadatos Dublin Core. Se finaliza destacando la necesidad de continuar con investigaciones que permitan concluir sobre la adecuación de estos tres atributos a las necesidades de los catalogadores, usuarios y a la realidad tecnológica

El cambio en la designación general de material (DGM) de las AACR a las RDA : Definición de los atributos tipo de contenido, tipo de medio y tipo de soporte

Se aborda el estudio de los atributos tipo de contenido, tipo de medio y tipo de soporte definidos por el código de catalogación Resource Description and Access (RDA) para solucionar los problemas que presentaba la lista de términos utilizadas para registrar la designación general de material (DGM) en las Anglo American Cataloging Rules (AACR). Los términos eran ambiguos combinando aspectos referidos al contenido y clase de material del recurso. Se parte de una exhaustiva revisión bibliográfica y del estudio de los documentos que se generaron en el proceso de elaboración del nuevo código. Se menciona el trabajo conjunto entre el Joint Steering Committee (JSC) y el estándar ONIX para el establecimiento de criterios que permitieron definir estos tres atributos, así como el aporte del modelo FRBR en la definición de los mismos. Se presentan ejemplos de registros bibliográficos donde se utilizan estos tres atributos en formato MARC21, ISBD consolidada a partir de la definición del área 0 y en el esquema de metadatos Dublin Core. Se finaliza destacando la necesidad de continuar con investigaciones que permitan concluir sobre la adecuación de estos tres atributos a las necesidades de los catalogadores, usuarios y a la realidad tecnológica