The course provides the basis for understanding of Earth’s climate system and of the mechanisms, feedbacks and natural and anthropogenic forcings determining its variability and the currently observed and projected global changes. It includes an introduction to climate modeling, through a hierarchy of approaches, from simple energy balance models to global earth-system models.

The course will provide an understanding of the main physical, chemical and biological mechanisms at work in shaping the Earths’s climate system, its variability and the interactions between its different subsystems. Students will acquire the tools and the knowledge needed to understand how anthropogenic use of resources and the associate climate forcings can drive significant global changes at different spatial and temporal scales and in different components of the climate system. They will acquire familiarity with currently observed climate changes, and an understanding of the approaches used to provide projections of future change. The students will learn basic elements of climate modelling, ranging from the ability to use simple mathematical models of energy balance to an introduction to numerical techniques and modeling approaches for different components of Earth system models. They will be introduced to techniques available for downscaling global climate data to the small scales needed for local application and to gauge associated uncertainties. The course also aims at providing the main instruments for working with gridded climate observations, reanalysis products and global climate model data, including knowledge on available data sources and software tools for manipulating gridded climate data and to be used for analysis.

Differential calculus. Classical physics, including thermodynamics. Fluid dynamics. Elements of probability and statistics. Basic knowledge of computer programming.

The course is organized in two parts: A) The global climate system (Classes: 27h, lab activities: 15h) • Introduction to the global climate system and its components; o Global energy balance o Atmospheric radiative transfer, radiative equilibrium and radiative-convective equilibrium o Atmospheric circulation (the role of rotation, primitive equations, thermally driven circulation, baroclinic disturbances, kinetic energy cycle) o Oceanic circulation and dynamics (thermohaline circulation, wind-driven circulation, sea ice) o Land/vegetation/cryosphere o The hydrological cycle • Forcings and feedbacks o Climate forcings (solar activity, orbital forcing, greenhouse gases, ozone, aerosols/cloud effects/volcanic eruptions, land surface changes, role of the ocean, anthropogenic climate forcing) o Climate feedbacks o Biogeochemical cycles and the global carbon cycle • Climate variability at different scales o The coupled system, natural climate variability (teleconnections and other modes of coupled variability at different timescales) o Climate change/Time evolution of the climate system o Paleoclimate, glacial cycles anthropocene/global warming o Evidence of current climate change (from observations and from numerical models). • Seasonal forecasting, decadal /multi-annual prediction, climate projections. • International model intercomparison projects, the IPCC, future scenarios • Climate sensitivity • Climate extremes B) Introduction to climate models (Classes: 27h, lab activities: 15h) • A hierarchy of models o Energy balance models o Box models o Radiative-Convective column models o Models of intermediate complexity o Global climate models o Earth system models • A brief introduction to numerical climate modeling methods (finite differences, spectral methods) • Modeling of Components of the climate system o Atmosphere (radiation, transport, convection parameterizations, clouds/precipitation/microphysics, surface parameterizations) o Ocean o Sea-ice models • Earth system modelling o Cryosphere o Land surface o Dynamic Vegetation o Aerosols/Atmospheric chemistry o Biogeochemical models o Model Coupling o Energy and mass balance in a coupled model • Dynamical downscaling and regional climate modelling • Statistical climate downscaling • Stochastic downscaling methods Lab activities: A) Analysis of gridded climate data (from observations and models) using common state-of-the-art data formats. Retrieval of data from available data sources and using software tools for manipulating gridded climate data. Analysis of model ensembles and evaluation of uncertainty. B) Solution and integration of a simple mathematical energy balance model, a brief introduction to numerical techniques, using a simple model of intermediate complexity and analyzing and interpreting its output. Precipitation downscaling.

The course will be organized in frontal lectures, covering the program of the course, exercises and numerical lab activities. Numerical lab activities will be organized dividing the students in small groups, performing tasks on analysis of global climate data, development of a simple energy balance model, numerical modelling techniques and an exercitation on running and analyzing a simple climate model of intermediate complexity.

The climate modelling primer 4th edition, Kendal McGuffie, Ann Henderson-Sellers, John Wiley & Sons, Ltd, ISBN 978-1-119-94336-5 (2014) Global Physical Climatology; Dennis L. Hartmann, Elsevier Science; 2 edition (2016) ISBN 978-0123285317 Climate system modelling, Kevin Trenberth, Cambridge University Press (2010) ISBN 978-0521128377 José P. Peixoto and Abraham H. Oort, Physics of Climate, American Institute of Physics (1992) ISBN 978-0-88318-712-8 Atmospheric and Oceanic Fluid Dynamics: Fundamentals and Large-scale Circulation, Geoffrey K. Vallis, Cambridge University Press; 2 edition (2017) ISBN 978-1107065505 IPCC (2014) Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. Stocker, T.F., Qin, D., Plattner, G-K., et al. (eds). https://www.ipcc.ch/assessment-report/ar5/

Modalità di esame: Prova scritta (in aula); Elaborato progettuale in gruppo;

Exam: Written test; Group project;

... The students are expected to demonstrate understanding and knowledge of the topics covered during the course. The final examination will consist of a written examination which may include open questions, multiple-choice questions and exercises on topics from all parts of the program, including the lab exercises. (2 hours)

Gli studenti e le studentesse con disabilità o con Disturbi Specifici di Apprendimento (DSA), oltre alla segnalazione tramite procedura informatizzata, sono invitati a comunicare anche direttamente al/la docente titolare dell'insegnamento, con un preavviso non inferiore ad una settimana dall'avvio della sessione d'esame, gli strumenti compensativi concordati con l'Unità Special Needs, al fine di permettere al/la docente la declinazione più idonea in riferimento alla specifica tipologia di esame.