Instituto de Ciências da Terra e do Espaço

About: Instituto de Ciências da Terra e do Espaço is a other organization based out in . It is known for research contribution in the topics: Geology & Environmental science. The organization has 1 authors who have published 3 publications receiving 20 citations.

A framework for ensemble modelling of climate change impacts on lakes worldwide: the ISIMIP Lake Sector

Abstract: Abstract. Empirical evidence demonstrates that lakes and reservoirs are warming across the globe. Consequently, there is an increased need to project future changes in lake thermal structure and resulting changes in lake biogeochemistry in order to plan for the likely impacts. Previous studies of the impacts of climate change on lakes have often relied on a single model forced with limited scenario-driven projections of future climate for a relatively small number of lakes. As a result, our understanding of the effects of climate change on lakes is fragmentary, based on scattered studies using different data sources and modelling protocols, and mainly focused on individual lakes or lake regions. This has precluded identification of the main impacts of climate change on lakes at global and regional scales and has likely contributed to the lack of lake water quality considerations in policy-relevant documents, such as the Assessment Reports of the Intergovernmental Panel on Climate Change (IPCC). Here, we describe a simulation protocol developed by the Lake Sector of the Inter-Sectoral Impact Model Intercomparison Project (ISIMIP) for simulating climate change impacts on lakes using an ensemble of lake models and climate change scenarios for ISIMIP phases 2 and 3. The protocol prescribes lake simulations driven by climate forcing from gridded observations and different Earth system models under various representative greenhouse gas concentration pathways (RCPs), all consistently bias-corrected on a 0.5∘ × 0.5∘ global grid. In ISIMIP phase 2, 11 lake models were forced with these data to project the thermal structure of 62 well-studied lakes where data were available for calibration under historical conditions, and using uncalibrated models for 17 500 lakes defined for all global grid cells containing lakes. In ISIMIP phase 3, this approach was expanded to consider more lakes, more models, and more processes. The ISIMIP Lake Sector is the largest international effort to project future water temperature, thermal structure, and ice phenology of lakes at local and global scales and paves the way for future simulations of the impacts of climate change on water quality and biogeochemistry in lakes.

Modelling fire-generated thunderstorms: Pedrógão Grande case study

Abstract: <p>The development of PyroCumulonimbus clouds during mega fire events has high impact in the evolution of the fire fronts and their development is frequently associated with strong convective processes due the heat and moisture released by the combustion. In 2017, Portugal was affected by several episodes of extreme wildfires with such a cloud system. The “Pedrógão Grande” mega fire caused more than 60 fatalities and burned a total area of almost 29,000 ha. In general, the atmospheric models do not account for fire-atmosphere interactions. Aiming to investigate the pyro-convective activity during the Pedrógão Grande mega fire, a numerical simulation was run with the Meso-NH model coupled to the ForeFire model. The Meso-NH model was configured into three nested domains. The horizontal resolution is 2000 m for the outer domain (600 km × 600 km). The inner computational grids have grid increments of respectively 400 m (120 km × 120 km) and 80 m (24 km × 24 km) for the innermost model. Initial and lateral boundary conditions for the outer domain are provided by ECMWF analysis, with updates every 6 h. The simulation with the coarsest resolution began on 17th June 2017 at 0600 UTC, with a progressive downscaling up to the finest resolution beginning at 1300 UTC. The vertical resolution is the same for all the nested domains, with 50 levels and a first level above the ground at 30 m height. The study used the reference fire propagation deduced from the official investigation (forced fire) and the emission of heat and vapour into the atmosphere was made using the ForeFire model. The results highlight the importance of the use of cloud resolving models configured with very-high spatial and temporal resolutions (80m, 10s) for representing the development of phenomena associated to pyro-convective activity, namely those occurring in the micro-scale from the cloud microphysics processes, like very-localised microbursts. This study was funded by national funds through FCT-Foundation for Science and Technology, I.P. under the PyroC.pt project (Ref. PCIF/MPG/0175/2019).</p>

Modelling pyro-convective activity and the meteorological conditions leading to mega-fires

Abstract: Mega-fires are wildfires that burn an area greater than 10.000 hectares. Despite being a minority in relation to the total number of fires, they are the one with the greatest negative impact on society and the environment. Associated with this wildfire type, the phenomenon of pyro-convection has been reported in several cases. Strong pyro-convective activity can lead to the formation of clouds within the smoke plume, also known as pyro-cumulus (PyroCu) or pyro-cumulonimbus (PyroCb). In 2017, Portugal recorded 11 mega-fires, of which 8 occurred on the 15th October. Since the photographic evidence of the formation of a PyroCu cloud, the chosen case study was the Quiaios mega-fire. The study aims to simulate the impact of a fire in the atmosphere, as well as the large-scale meteorological conditions that were affecting Portugal during the mega-fires. For this purpose, two numerical simulations were performed using the MesoNH atmospheric model: a coupled simulation with the ForeFire fire propagation model, with 3 nested domains with resolution of 2000m, 400m and 80m (300 by 300 grid points), and a large-scale non-coupled simulation, with a 15km resolution (300 by 250 grid points) to study the large-scale conditions. The coupled simulation allowed identifying the formation of a PyroCu cloud composed by different species of hydrometeors, namely graupel and rain droplets. The pyro-cloud developed inside the plume due the vertical transport of water vapor to higher levels. In the context of large scale, the simulation well represented the evolution of hurricane Ophelia, showing the change in wind direction from Southeast to Southwest in Portuguese territory, which created a favourable condition to the intensification of the active fires and the development of PyroCb clouds during the late afternoon. This study was funded by national funds through FCT-Foundation for Science and Technology, I.P. under the PyroC.pt project (Ref. PCIF/MPG/0175/2019).