KENYATTA UNIVERSITY – INSTITUTE OF OPENING LEARNING DEPARTMENT OF GEOGRAPHY III AGE 301: PHYSICAL GEOGRAPHY DR. JOY APIYO OBANDO & DR. GEORGE LUKOYE MAKOKHA © 2005 FOREWORD Physical Geography III is a course that builds on the knowledge gained from the study of Physical Geography I and II. It builds on the knowledge of the atmosphere introduced in Physical Geography I and introduces the basic concepts of Biogeography, mainly concerned with the factors that determine the distribution of living organisms and their impact on the environment. The course also examines the scope and growth of Biogeography, vegetation and soils. Aspects of the atmosphere such as climatic elements and their distribution, climatic factors, climatic classification schemes and climatic change are adequately covered. The overall objective of this course is to enable the learner to be able to explain the concepts, linkages and processes in the Atmosphere and Biosphere. Learners are expected after studying this course to explain the patterns and controls of global climates, vegetation and soils and their influence on the Biosphere. They should also be able to explain the effect of biotic and abiotic factors on the distribution of living organisms. Lessons 1 to 4 discuss the aspects of the atmosphere, while the biosphere is covered in Lessons 5 to 10. TABLE OF CONTENTS PAGE FOREWORD.............................................................................................................................I LESSON 1. CLIMATIC ELEMENTS AND THEIR GLOBAL DISTRIBUTION ....... 1 1.1. Introduction ................................................................................................................ 1 1.2. Objectives................................................................................................................... 1 1.3. Temperature ............................................................................................................... 1 1.4. Evaporation ................................................................................................................ 6 1.5. Precipitation ............................................................................................................... 8 1.6. Summary .................................................................................................................. 10 1.7. Definitions of Key Words ........................................................................................ 11 1.8. Revision Questions................................................................................................... 12 1.9. Further Reading........................................................................................................ 12 LESSON 2. CLIMATIC CONTROLS AND FACTORS................................................ 13 2.1. Introduction .............................................................................................................. 13 2.2. Objectives................................................................................................................. 13 2.3. Air Masses................................................................................................................ 13 2.4. Convergence of air masses and fronts...................................................................... 16 2.5. Frontal systems......................................................................................................... 16 2.6. Latitude..................................................................................................................... 19 2.7. Altitude..................................................................................................................... 20 2.8. Land and water masses............................................................................................. 21 2.9. Relief features .......................................................................................................... 21 2.10. Summary .............................................................................................................. 21 2.11. Definition of Key Words...................................................................................... 21 2.12. Revision Questions............................................................................................... 22 2.13. Further Reading.................................................................................................... 22 LESSON 3. CLIMATIC CLASSIFICATION, MICRO AND MAN-MADE CLIMATES 23 3.1. Introduction .............................................................................................................. 23 3.2. Objectives................................................................................................................. 23 3.3. Purpose and problems of climatic classification...................................................... 23 3.4. Approaches to climatic classification....................................................................... 24 ii 3.5. Genetic classification schemes................................................................................. 25 3.6. Generic/Empirical Classification Schemes .............................................................. 27 3.7. Climatic regions of the world................................................................................... 29 3.8. Micro-Climates or Local Climates........................................................................... 30 3.9. Man made climates................................................................................................... 31 3.10. Cloud seeding....................................................................................................... 32 3.11. Summary .............................................................................................................. 32 3.12. Definitions of Key Words .................................................................................... 33 3.13. Revision Questions............................................................................................... 33 3.14. Further Reading.................................................................................................... 33 LESSON 4. CLIMATE CHANGE AND FLUCTUATIONS.......................................... 35 4.1. Introduction .............................................................................................................. 35 4.2. Objectives................................................................................................................. 35 4.3. Natural climate change............................................................................................. 35 4.4. Man-made climatic change ...................................................................................... 37 4.5. Global warming and climate changes ...................................................................... 38 4.6. Summary .................................................................................................................. 39 4.7. Definitions of Key Words ........................................................................................ 39 4.8. Revision Questions................................................................................................... 39 4.9. Further Reading........................................................................................................ 39 LESSON 5. SCIENCE OF BIOGEOGRAPHY............................................................... 41 5.1. Introduction .............................................................................................................. 41 5.2. The objectives .......................................................................................................... 41 5.3. Definitions and concepts .......................................................................................... 41 5.4. The scope and growth of Biogeography .................................................................. 42 5.5. The biosphere and role of humankind...................................................................... 43 5.6. Summary .................................................................................................................. 43 5.7. Definition of key words............................................................................................ 44 5.8. Revision Questions................................................................................................... 44 5.9. Further Reading........................................................................................................ 44 LESSON 6. ECOSYSTEM CONCEPT ............................................................................ 45 6.1. Introduction .............................................................................................................. 45 6.2. The objectives .......................................................................................................... 45 iii 6.3. The Ecosystem ......................................................................................................... 45 6.4. Ecosystem structure and function ............................................................................ 46 6.5. Energy flow in ecosystems....................................................................................... 47 6.6. Nutrient cycling in the ecosystem ............................................................................ 49 6.7. Summary .................................................................................................................