Projekt

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Projektübung Klimamodellierung

• André Paul

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Vorbesprechung
Projektübung Klimamodellierung (05-3034) A. Paul
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Veranstaltungsdaten

• Veranstaltungskennziffer 05-3034
• ECTS-Punkte 2.5
• 2 SWS, Mi von 1300-1500, GEO 1480/90

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Website

• http//www.palmod.uni-bremen.de/apau/projektuebun
  g/Material_zur_LV.html

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Inhalt

• Einführung in die wissenschaftliche
  Programmierung anhand einfacher Beispielprogramme
  und ihrer schrittweisen Veränderung
• Beschreibung des Klimasystems mit Hilfe von
  Erhaltungsgleichungen
• Zeitliche und räumliche Diskretisierung von
  Erhaltungsgleichungen
• Numerische Lösung diskretisierter
  Erhaltungsgleichungen auf einem Computer
• Numerische Experimente mit physikalischen Ozean-
  und Atmosphärenmodellen

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Ziel

• Einführung in die Methoden der Klimamodellierung
  und deren praktische Anwendung (weg vom
  Klimamodell als "black box")

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Bewertung

• Anforderungen selbstständige Lösung von
  Übungsaufgaben auf dem Computer (während der
  Übung/im Computerraum)
• Referat

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Literatur

• Stocker, T (2005) Skript zur Vorlesung
  Einführung in die Klimamodellierung, 141
  Seiten, PDF (16 MB), korrigierte Version
  15.2.2005
• http//www.climate.unibe.ch/stocker/papers/skript
  0405.pdf

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Einführung in die wissenschaftliche
Programmierung mit Fortran 90

• Verwendung von MATLAB o. ä. freigestellt
• Schleifen, Lesen und Schreiben von Dateien, usw.

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Reading

• The following notes are based on
• Ellis, T.M.R., Phillips, Ivor R., and Lahey,
  Thomas M. Fortran 90 Programming, Addison-Wesley
  Publishing Company.

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Telling a Computer What To Do

• To get a computer to perform a specific task it
  must be given a sequence of unambiguous
  instructions or a program.
• Generating a program
• Text file with instructions (Source Code
  Fortran 90)
• Translation into computer-compatible form
  (Compiler)
• Executable Program

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The Linux look and feel

• Cygwin is a Linux-like environment for Windows
  that consists of two parts
• A DLL (Dynamic Link Library, cygwin1.dll)
• A collection of tools, which provide Linux look
  and feel
• Link http//www.cygwin.com

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A few useful Linux commands

• pwd print name of current/working directory
• ls list directory contents
• cd change directory
• mkdir make directories
• rm remove files or diretories
• man format and display the on-line manual pages
  (e.g. man pwd)

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How to start cygwin

• Open cygwin window by double-clicking on the
  start_cygwin DOS batchfile provided with this
  exercise
• If this does not work ...

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Creating and Running a Program

• Invoke the editor from the Start menu, or type

into the cygwin window to create a file called
hello.f90.
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Creating and Running a Program

• Type the following source code
• Compile by typing g95 hello.f90 (in the cygwin
  window)
• Run the program by typing ./a.exe (g95 by default
  creates an executable called a.exe)

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Basic Fortran 90 concepts

• All words which have a special meaning in Fortran
  are known as keywords.
• Every main program unit must start with a PROGRAM
  statement which consists of the word PROGRAM
  followed by the name of the program as given by
  the programmer.

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Avoid implicit declaration

• The special IMPLICIT NONE statement should always
  be placed immediately after the PROGRAM
  statement. It instructs the compiler that all
  variables must be declared before use.

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Basic building blocks

• A main program unit

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REAL and INTEGER variables

• Use the INTEGER name statement to declare a
  whole-number variable
• Use the REAL name statement to declare a
  floating-point variable

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Repeating parts of your program
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Using files to preserve data

• Connecting external files to your program
• Connect a file to a unit by OPEN(UNITunit_number
  ,FILEfile_name), where unit_number is an integer
  number, variable or parameter and file_name is a
  character expression.

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Using files to preserve data

• Write a record to a file by WRITE
  (UNITunit_number,FMT)
• Disconnect a file from a unit by means of a CLOSE
  (UNITunit_number) statement