Global land-atmosphere coupling associated with cold climate processes

Tese de doutoramento, Ciências Geofísicas e da Geoinformação (Meteorologia), Universidade de Lisboa, Faculdade de Ciências, 2011This dissertation constitutes an assessment of the role of cold processes, associated with snow cover, in controlling the land-atmosphere coupling. The work was based on model simulations, including offline simulations with the land surface model HTESSEL, and coupled atmosphere simulations with the EC-EARTH climate model. A revised snow scheme was developed and tested in HTESSEL and EC-EARTH. The snow scheme is currently operational at the European Centre for Medium-Range Weather Forecasts integrated forecast system, and in the default configuration of EC-EARTH. The improved representation of the snowpack dynamics in HTESSEL resulted in improvements in the near surface temperature simulations of EC-EARTH. The new snow scheme development was complemented with the option of multi-layer version that showed its potential in modeling thick snowpacks. A key process was the snow thermal insulation that led to significant improvements of the surface water and energy balance components. Similar findings were observed when coupling the snow scheme to lake ice, where lake ice duration was significantly improved. An assessment on the snow cover sensitivity to horizontal resolution, parameterizations and atmospheric forcing within HTESSEL highlighted the role of the atmospheric forcing accuracy and snowpack parameterizations in detriment of horizontal resolution over flat regions. A set of experiments with and without free snow evolution was carried out with EC-EARTH to assess the impact of the interannual variability of snow cover on near surface and soil temperatures. It was found that snow cover interannual variability explained up to 60% of the total interannual variability of near surface temperature over snow covered regions. Although these findings are model dependent, the results showed consistency with previously published work. Furthermore, the detailed validation of the snow dynamics simulations in HTESSEL and EC-EARTH guarantees consistency of the results.Fundação para a Ciência e a Tecnologia (FCT,SFRH/BD/35789/2007); Fundação Calouste Gulbenkia

Impact of land-surface initialization on sub-seasonal to seasonal forecasts over Europe

The final publication is available at Springer via http://dx.doi.org/10.1007/s00382-015-2879-4Land surfaces and soil conditions are key sources of climate predictability at the seasonal time scale. In order to estimate how the initialization of the land surface affects the predictability at seasonal time scale, we run two sets of seasonal hindcasts with the general circulation model EC-Earth2.3. The initialization of those hindcasts is done either with climatological or realistic land initialization in May using the ERA-Land re-analysis. Results show significant improvements in the initialized run occurring up to the last forecast month. The prediction of near-surface summer temperatures and precipitation at the global scale and over Europe are improved, as well as the warm extremes prediction. As an illustration, we show that the 2010 Russian heat wave is only predicted when soil moisture is initialized. No significant improvement is found for the retrospective prediction of the 2003 European heat wave, suggesting this event to be mainly large-scale driven. Thus, we confirm that late-spring soil moisture conditions can be decisive in triggering high-impact events in the following summer in Europe. Accordingly, accurate land-surface initial conditions are essential for seasonal predictions.The research leading to these results has received funding from the EU Seventh Framework Programme FP7 (2007–2013) under grant agreements 308378 (SPECS), 282378 (DEN-FREE) and 607085 (EUCLEIA), and from the Spanish Ministerio de Economía y Competitividad (MINECO) under the project CGL2013-41055-R. We acknowledge the s2dverification R-based package (http://cran.r-project.org/web/packages/s2dverification/index.html). We also thank ECMWF for providing the ERA-Land initial conditions and computing resources through the SPICCF Special Project.Peer ReviewedPostprint (author's final draft

Trends, variability and predictive skill of the ocean heat content in North Atlantic: an analysis with the EC-Earth3 model

This study investigates linear trends, variability and predictive skill of the upper ocean heat content (OHC) in the North Atlantic basin. This is a region where strong decadal variability superimposes the externally forced trends, introducing important differences in the local warming rates and leading in the case of the Central Subpolar North Atlantic to an overall long-term cooling. Our analysis aims to better understand these regional differences, by investigating how internal and forced variability contribute to local trends, exploring also their role on the local prediction skill. The analysis combines the study of three ocean reanalyses to document the uncertainties related to observations with two sets of CMIP6 experiments performed with the global coupled climate model EC-Earth3: a historical ensemble to characterise the forced signals, and a retrospective decadal prediction system to additionally characterise the contributions from internal climate variability. Our results show that internal variability is essential to understand the spatial pattern of North Atlantic OHC trends, contributing decisively to the local trends and providing high levels of predictive skill in the Eastern Subpolar North Atlantic and the Irminger and Iceland Seas, and to a lesser extent in the Labrador Sea. Skill and trends in other areas like the Subtropical North Atlantic, or the Gulf Stream Extension are mostly externally forced. Large observational and modeling uncertainties affect the trends and interannual variability in the Central Subpolar North Atlantic, the only region exhibiting a cooling during the study period, uncertainties that might explain the very poor local predictive skill.Teresa Carmo-Costa, Ana Teles-Machado and Emanuel Dutra would like to acknowledge the financial support from FCT through projects FCT-UIDB/50019/2020 and PD/BD/142785/2018. Furthermore, Ana Teles-Machado acknowledges SARDINHA2020 (MAR2020) and ROADMAP (JPIOCEANS/ 0001/2019). Roberto Bilbao was supported by the European Commission H2020 projects EUCP (Grant no. 776613). Pablo Ortega was supported by the Spanish Ministry of Economy, Industry and Competitiveness through the Ramon y Cajal grant RYC-2017-22772.Peer ReviewedPostprint (published version

A Paisagem Percebida por um Sistema Complexo

What is the subject that perceives the Landscape? What is the perception, the knowledge, realized by this subject? In Western Culture the man (in moral terms), or subject (in terms of knowledge), was considered a rational and equilibrated being, whose essence differentied and transcended the physical matter. The Theory of Complexity comes new readings about the subject and his perception, with repercussions in the way of apprehending Landscape. It is intended to discuss the conception of the subject by Complexity, through the Theory of the Observer, and some repercussions on the perception of the Landscape. The arguments were based on a cybernetic-functional biological direction, presenting the proposal of Biology of the Knowledge. The contacts with the Landscape dialogue with autors that reflect the landscape, presenting congruences and divergences. By Complexity Theory the analytical science is not an objective field, but a field of knowledge dependent of the subject and defined by a methodology. In this way, there is no rational subject capable of knowing the objective reality. The subject / observer is a complex system and the perception of the Landscape becomes momentary and ephemeral. The subject as a organism is characterized by being a process in transformation, with the perception of the landscape change as this transformation.O que é o sujeito que percebe a Paisagem? O que é a percepção, o conhecimento, realizado por este sujeito? Na cultura científica moderna o sujeito do conhecimento foi considerado um ser racional e equilibrado que poderia conhecer o mundo objetivamente, sem a influência das subjetividades individuais e sociais. A percepção da Paisagem na Geografia pela abordagem sistêmica carrega essa influência. A Teoria da Complexidade traz novas leituras sobre o sujeito e sua percepção, com repercussões sobre a percepção da Paisagem. Os argumentos se deram num viés biológico cibernético-funcional, apresentando a proposta da Biologia do Conhecer. Os contatos com a Paisagem se deram pelas congruências e divergências com leituras já realizadas pelos autores conhecidos. Pela Complexidade a ciência analítica deixa de ser um campo objetivo, não existindo um sujeito racional , e sim um sujeito bioantroposocial auto-reflexivo que buscar uma objetivação de suas práticas. O sujeito/observador é um sistema complexo e a Paisagem se torna ao mesmo tempo individual e social, pois não separa a ideologia do sujeito (que é socialmente construída) da sua individualidade autônoma – e isso em termos biológicos. A percepção da Paisagem se torna momentânea e efêmera,dependente das condições singulares de quem observa, no momento que observa; variando de acordo com as condições do organismo em sua relação com o ambiente – que também é variante. O sujeito como o organismo caracteriza-se por ser um processo em transformação, com a leitura da paisagem variando de acordo com essa ininterrupta transformação

Drought and food security – Improving decision-support via new technologies and innovative collaboration

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The Effect of Strategic Choices and Management Control Systems on Organizational Performance

The study investigates the effect of generic strategic choices and management control systems (MCS) on the organizational performance of large and medium-sized companies located in Espírito Santo, using Contingency Theory as the theoretical framework. It is a quantitative study, using a survey as the data collection technique. 73 questionnaires were validated, after being completed by those responsible for the controlling or related area of these enterprises over the period between February and April of 2014. The data analysis was performed using the structural equations modeling technique. The main results indicate that: (i) competitive forces shape the strategy adopted by the organizations surveyed, however, contrary to what the literature predicts, those companies that operate in more competitive environments choose a strategy of cost leadership instead of differentiation; (ii) the design and use of the MCS is influenced by the strategy chosen, and the use of contemporary management practices is associated with a differentiation strategy; (iii) strategic choices and the MCS have a positive impact on organizational performance. In addition, those companies that combine differentiation strategy with contemporary management practices perform better than the other companies analyzed.O estudo investiga o efeito das escolhas estratégicas genéricas e dos sistemas de controle gerencial (SCG) no desempenho organizacional de empresas de médio e grande porte localizadas no Espírito Santo, tendo a teoria da contingência como plataforma teórica. Trata-se de uma pesquisa quantitativa, com a utilização de um survey como técnica de coleta de dados. Foram validados 73 questionários, respondidos pelos responsáveis pela controladoria ou área afim dessas empresas, no período de fevereiro a abril de 2014. A análise dos dados foi feita usando a técnica da modelagem de equações estruturais. Os principais resultados indicam que: (i) as forças competitivas moldam a estratégia adotada pelas organizações pesquisadas, porém, de forma contrária à prevista na literatura, ou seja, as empresas que atuam em ambientes com maior competição escolhem como estratégia a busca pela liderança em custo, ao invés da diferenciação; (ii) o desenho do SCG é influenciado pela estratégia escolhida, sendo que o uso de práticas gerenciais contemporâneas está associado a uma estratégia de diferenciação; (iii) as escolhas estratégicas e o SCG possuem impacto positivo no desempenho organizacional. Além disso, empresas que combinam estratégia de diferenciação com práticas gerenciais contemporâneas possuem desempenho superior às demais empresas analisadas

Impact of springtime Himalayan-Tibetan Plateau snowpack on the onset of the Indian summer monsoon in coupled seasonal forecasts

The springtime snowpack over the Himalayan–Tibetan Plateau (HTP) region and Eurasia has long been suggested to be an influential factor on the onset of the Indian summer monsoon. To assess the impact of realistic initialization of springtime snow over HTP on the onset of the Indian summer monsoon, we examine a suite of coupled ocean–atmosphere 4-month ensemble reforecasts made at the European Centre for Medium-Range Weather Forecasts, using their Seasonal Forecasting System 4. The reforecasts were initialized on 1 April every year for the period 1981–2010. In these seasonal reforecasts, the snow is initialized “realistically” with ERA-Interim/Land Reanalysis. In addition, we carried out an additional set of forecasts, identical in all aspects except that initial conditions for snow-related land surface variables over the HTP region are randomized. We show that high snow depth over HTP influences the meridional tropospheric temperature gradient reversal that marks the monsoon onset. Composite difference based on a normalized HTP snow index reveal that, in high snow years, (1) the onset is delayed by about 8 days, and (2) negative precipitation anomalies and warm surface conditions prevail over India. We show that about half of this delay can be attributed to the realistic initialization of snow over the HTP region. We further demonstrate that high April snow depths over HTP are not uniquely influenced by El Nino-Southern Oscillation, the Indian Ocean Dipole or the North Atlantic Oscillation.RS and YOR were supported by the Research Council of Norway through the NORINDIA Project (#216576). AW and YOR were also supported by the EU project SPECS funded by the European Commission’s Seventh Framework Research Programme under the grant agreement 308378.Peer ReviewedPostprint (published version