Anders Persson's lectures March-May 2016
Anders Persson's lectures March-May 2016
These lectures were held at RSHU in St Petersburg 21 March-29 April, at the University in Pskov 7-8 April and at RosHydromet in Moscow 16-17 May. Some topics were presented at different occasions in slightly different forms. The Pskov lectures might be slightly simplified, the Moscow video recoded lectures shorter in time.
1. Dynamical meteorology
1.1 The Coriolis effect
Abstract:The Coriolis Effect, so fundamental in the atmospheric and oceanographic sciences, nevertheless has got a poor pedagogical treatment in most textbooks used worldwide, at best incomplete, at worst erroneously but mostly misleading.
The five seminars will try to give a new look at the Coriolis Effect, starting with 1) how Coriolis looked at it in 1835, then 2) how his view, in a mathematically consistent way can bring new light on the terrestrial Coriolis Effect, 3-4) the consequences of the Coriolis Effect, the "inertia circles", can be applied to give some intuitive "feel" for the motions in fluids, the atmosphere and the oceans.
It will be argued that the common talk of the Coriolis force "deflecting" moving objects, is misleading: it does more than "deflect". It tries to bring back all moving bodies from whence they came, thus the notion of "Coriolis stiffness" in rotating fluids coined by Cambridge scientists.
Finally, I will in 5) discuss how the Coriolis Effect has been presented in some Soviet textbooks on dynamic meteorology.
1.1.1 The Coriolis effect according to Coriolis I Coriolis
1.1.2 The Coriolis effect on a rotating planet Coriolis II Planet
1.1.3 Some consequences of the Coriolis effect Coriolis III Fronts
1.1.4 Some more consequences of the Coriolis effect Coriolis IV Jetstreams
1.1.5 A critical look, in Russian, at Soviet textbook treatment of the Coriolis effect Coriolis Critique
1.2 Albert Einstein's contribution to meteorology explaining the role of frcition in weakening of atmospheric circulation systems Einstein
1.3 The geostrophic, an elementary approach wind Geostrophic wind
Rossby's contribution to large scale dynamics
Abstract: The history behind the discovery of C.-G. Rossby's planetary waves will be outlined, as well as how he came to introduce the concept of "group velocity" into dynamic meteorology. The latter concept has proved its value by increasing our understanding of how different synoptic, baroclinic systems interact over long distances. It is not only helpful to understand what causes a bad forecast but also where extra observations should be positioned.
1.4 They are nowadays called "Rossby waves", but during his life time they were called "planetary waves" to make clear that it was a feature of the large scale flow Rossby's planetary waves
1.5 The way upstream cyclones affect downstream ones can be understood kinematically by the concept of "group velocity" Group velocity and downstream development
2. Kalman filtering
Abstract: A lot of the output from NWP cannot be used directly but have to be subject to manual or automated post-processing to remove systematic errors and/or damp non-systematic. For the later a "frequentist" method, Model Output Statistics (MOS) has traditionally been used. It is based on linear regression analysis between previous forecasts and the verifications (historical archived data 3-5 years back).
For some purposes an adaptive approach may be favoured. Here only the very last forecast and its verification are used to update the correction equation. This, essentially Bayesian approach, has been tried with a very simple Kalman filter.
The problems and challenges with statistical interpretation (primarily related to temperature and wind speed forecasts) is outlined and the Kalman filter and its application in this case is demonstrated. In later lectures related problems and application about interpretation of verification statistics and the use of ensembles (big or small) for operational weather forecasting will be presented.
2.1 Introduction to statistical interpretation Kalman I RSHU
2.2 Introduction to 1- and 2-dimensional Kalman filtering Kalman II RSHU
2.3 Verification of Kalman filtered forecasts Kalman III RSHU
3. History of meteorology
3.1 Early history of American and Swedish NWP NWP history I
3.2 Early history of British NWP NWP history II
3.3 Erik Palmén and Vilho Väisälä, two world leading Finnish meteorologists Vaisala_Palmen
4. Probabilities and statistics
4.1 The sciences of probabilities and statistics are relatively new because it took long for Mankind to accept complete randomness Probability History
4.2 Markov chains offers some nice mathematical toys simulation weather forecasting Markov chains
4.3 The ultimate purpose of weather forecasting is to guide decision making and uncertainty information in the form of probabilities is the best way Probability Decisions
It Appears the self-Evident That good weather forecasts are more useful than bad forecasts and that a weather forecaster should be confident and not hesitate. However, the this seminar will of show, using the an example from the 1930's USA, how
1. A private weather firm earned good money from producing bad weather forecasts, worse than the official US Weather Bureau's.
2. How the Weather Bureau could have fought back by becoming more hesitant, more uncertain
3. How the Weather Bureau could have defeated the private firm by issuing probabilistic weather forecasts
To improve deterministic weather forecasts is a long and expensive endeavour, at best they will improve by one forecast day per decade. However, applying the concept of openly declaring the "uncertainty" can improve the weather forecasts almost for no cost and in a few weeks.
5. Moscow video recorded lectures
5.1 Some explanations of dynamical processes are incomplete, misleading and even sometimes erroneous Common misunderstandings
5.2 One of the most fundamental mechanism is the atmosphere and ocean is the effect of the Earth's rotation The Coriolis Effect
5.3 By using the concept of inertia circle, the tendency of the Earth's rotation to make moving bodies return, some atmospheric and oceanographic processes can be easily understood Some consequences of the Coriolis Effect
5.4 A correct explanation of the acceleration of a air parcel in a constant pressure gradient opens the door to understanding three types of jet streams Jet streams
5.5 They are nowadays called "Rossby waves", but during his life time they were called "planetary waves" to make clear that it was a feature of the large scale flow Rossby planetary waves
5.6 The way upstream cyclones affect downstream ones can be understood kinematically by the concept of "group velocity" Downstream development
5.7 A Bayesian approach to statistical interpretation of numerical weather forecast output Kalman filtering
5.8 The sciences of probabilities and statistics are relatively new because it took long for Mankind to accept complete randomness History of probability
5.9 The ultimate purpose of weather forecasting is to guide decision making and uncertainty information in the form of probabilities is the best way Decision making
5.10 Although the mathematics often is simple in statistics, the interpretation of the results can be very counter intuitive and lead to wrong judgements Statistical pitfalls
6.RosHydroMet lectures
6.1 The ultimate purpose of weather forecasting is to guide decision making and uncertainty information in the form of probabilities is the best way Moscow seminar 1 Probabilities
6.2 A Bayesian approach to statistical interpretation of numerical weather forecast output Moscow seminar 2 Kalman
6.3 One of the most fundamental mechanism is the atmosphere and ocean is the effect of the Earth's rotation Moscow seminar 3 Coriolis
6.4 They are nowadays called "Rossby waves", but during his life time they were called "planetary waves" to make clear that it was a feature of the large scale flow Moscow seminar 4 Rossby's waves
7. Pskov lectures
7.1 Some explanations of dynamical processes are incomplete, misleading and even sometimes erroneous, and this is in particular true for the understanding how the Earth's rotation affects the winds Pskov 1 Trade winds
7.2 The explanation of the acceleration of a air parcel in a constant pressure gradient is often erroneous, which is a pity since the correct explanation opens the door to understanding three types of jet streams Pskov 2 Jet streams
7.3 They are nowadays called "Rossby waves", but during his life time they were called "planetary waves" to make clear that it was a feature of the large scale flow Pskov 3 Planetary waves
Информационные материалы
Интернет-ресурсы
1)User guide to ECMWF forecast products
2) A course on probability by Anders Persson. The lecture series was first given as a 5-day course in Bologna, Italy in February 2015.
3) Texts (in English) from the French project
4) Video-lectures, ИПК Росгидромет
Статьи Андерса Перссона
1) Hadley’s Principle: Understanding and Misunderstanding the Trade Winds
2) Proving that the Earth rotates by measuring the deflection of objects dropped in a deep mine.
The French-German mathematical contest between Pierre Simon de Laplace and Friedrich Gauß 1803
3) Albert Einstein and Frau Schrödinger’s tea cup
4) Being wrong – but for good reasons. French 18th century attempts to understand the Trade winds through fluid dynamic experiments 200 years ahead of their times
5) Back to basics: Coriolis: Part 2 - The Coriolis force according to Coriolis
6) The obstructive Coriolis force (Coriolis Part 4)
7) The Coriolis force and drifting icebergs (Coriolis Part 6)
8) Mathematics versus common sense: the problem of how to communicate dynamic meteorology
9) Early operational Numerical Weather Prediction outside the USA: an historical Introduction. Part 1: Internationalism and engineering NWP in Sweden, 1952–69
10) Early operational Numerical Weather Prediction outside the USA: an historical introduction: Part II: Twenty countries around the world
11) Early operational Numerical Weather Prediction outside the USA: an historical introduction Part III: Endurance and mathematics – British NWP, 1948–1965
12) Back to basics: Coriolis: Part 1 - What is the Coriolis force?
13) Back to basics: Coriolis: Part 3 - The Coriolis force on the physical earth
14) The Coriolis force and the geostrophic wind (Coriolis Part 5)
15) The Coriolis force and the subtropical jet stream (Coriolis Part 8)
16) The deceptive Coriolis force derivation
17) Proving that the earth rotates: The Coriolis force and Newton’s falling apple (Coriolis Part 9)
18) The Coriolis force and the subtropical jet stream
19) Hadley’s Principle: Part 1 – A brainchild with many fathers
20) Hadley’s Principle: Part 2 – Hadley rose to fame thanks to the Germans
21) Hadley’s Principle: Part 3 – Hadley and the British
22) Automation and Human Expertise in Operational River Forecasting
23) SUTCLIFFE, REGINALD COCKCROFT (biography)
24) Tor Bergeron's time in the Soviet Union under Stalin (I)
25) Rossby waves - do they exist?
26) Tor Bergeron (biography)
27) Tor Bergeron advice
28) Notes and Correspondence. Is the Coriolis effect an ‘optical illusion’?
29) The Coriolis Effect:Four centuries of conflict between common sense and mathematics,Part I: A history to 1885
Видеофайлы
1) The Coriolis Effect, Part 1
2) The Coriolis Effect, Part 2
3) Convection and Conduction
4) Uncertainty Forecasts & General Public End-Users - Dr. Susan Joslyn, University of Washington
Презентации
Geostrophic wind
Jet streams
Книги
Roland Stull (author of "Introduction to Boundary Layer Meteorology"),has written a new general meteorology text book, Practical Meteorology.
It's an algebra-based text covering a wide range of topics.
1) Dynamics
2) Atmospheric Forces & Winds
3)General Circulation
(прогноз РГГМУ)
