1. Uncontrolled copy not subject to amendment Basic Navigation Using Map and Compass

2. Learning Outcome 5: Be able to recognise weather conditions that affect land navigation

3. Hot and Cold Air Masses BECAUSE OF THE RELATIONSHIP OF THE EARTH’S ORBIT AROUND THE SUN TO THE TIME OF YEAR, THE ANGLE THAT THE SUN’S RAYS HIT THE EARTH VARY WITH TIME. UK SUMMER AUSTRALIA WINTER. AUSTRALIA SUMMER UK WINTER.

4. MOISTURE IN THE AIR ALL AIR CONTAINS MOISTURE. IT IS ONLY THE AMOUNT THAT VARIES. HOW THE AIR ARRIVES AT OUR SHORES AFFECTS THE MOISTURE IN THE AIR. IF IT HAS TRAVELLED OVER LAND IT IS MOST LIKELY TO BE DRY. LITTLE MOISTURE. IF IT HAS TRAVELLED OVER THE SEA IT IS MOST LIKELY TO BE WET. LOTS OF MOISTURE.

5. MOISTURE IN THE AIR THE AMOUNT OF MOISTURE SUSPENDED IN THE AIR IS DEPENDENT ON THE AIR TEMPERATURE. THE WARMER THE AIR THE MORE MOISTURE IT WILL HOLD. THE MOISTURE CANNOT BE SEEN UNTIL THE AIR BECOMES SATURATED AND THE MOISTURE COMES OUT OF SUSPENSION AND FORMS CLOUDS. THE TYPE OF CLOUD FORMED IS DEPENDENT ON THE RATE OF TEMPERATURE CHANGE AND THE STRENGTH OF THE WIND. THE SATURATION POINT IS KNOWN AS THE ‘DEW POINT’.

6. Main Air Masses Width of the arrows indicates the frequency of occurrence

7. Main Air Masses ARCTIC MARITIME – VERY COLD AND WET/SNOW POLAR MARITIME – COLD AND WET/SNOW RETURNING POLAR MARITIME – COOL AND WET TROPICAL MARITIME – WARM AND WET (GULF STREAM) TROPICAL CONTINENTAL - HOT AND DRY POLAR CONTINENTAL – COLD AND DRY IN WINTER WARM AND DRY IN SUMMER

8. BASED ON SEA LEVEL ICAO STANDARD ATMOSPHERE ACCEPTED AROUND THE WORLD PRESSURE1013.25 Mb TEMPERATURE15º C LAPSE RATE OF -1.98ºC/1000Ft

9. Weather Map WIND CIRCULATES ANTI-CLOCKWISE AROUND A ‘LOW’. AND CLOCKWISE AROUND A ‘HIGH’.

10. Fronts and Frontal Depressions Numbers refer to pressure in millibars

11. Weather Map – Westerly Winds

12. Depression Chart

13. Depression

14. Fronts and Frontal Depressions Section through a frontal system Cold front is steeper than the warm front

15. High and Low Pressure

17. Upper Winds Weather map showing isobars for both upper and lower winds. Lower winds affect the weather we get. Upper winds affect the speed the weather system moves.

18. SURFCE PRESSURE CHART – NORTH ATLANTIC & EUROPE

20. Names For Clouds The names for clouds are usually combinations of the following prefixes or suffixes: Stratus/strato = flat/layered and smooth Cumulus/cumulo = heaped up/puffy, like cauliflower Cirrus/cirro = High up/wispy Alto = Medium level Nimbus/Nimbo = Rain-bearing cloud

21. CLOUD LEVELS HIGH CLOUDSBASE USUALLY 20,000ft OR ABOVE OVER UK. TYPES – CIRRUS CIRROCUMULUS CIROSTRATUS MEDIUM CLOUDSBASE USUALLY BETWEEN 6,500ft AND 20,000ft OVER UK. TYPES – ALTO CUMULUS ALTO STRATUS NIMBOSTRATUS BASE USUALLY BELOW 6,500ft OVER UK. LOW CLOUDS TYPES – STRATO CUMULUS STRATUS CUMULUS CUMULONIMBUS

25. Approaching Rain

26. Warm Front

27. Cold Front

28. Occluded Front

29. Depression Cross Section Cloud Type

30. Depression Cross Section Air movement

31. TYPES OF CLOUD

36. CUMULONIMBUS CLOUD TYPICAL ANVIL HEAD TO THE CLOUD AS THE RISING AIR COMES TO A STOP AND THE UPPER WINDS PULL THE TOP CLOUD OFF THE COLUMN.

37. Local Warming

38. Pockets of Air

39. Thermals above

40. Air rising over mountains

41. Rising Air Dewpoint

42. Cloudy foothills

43. Funnels and Eddies

44. Banner Clouds

45. Temperature Inversion

47. stratus cumulonimbus cumulus stratocumulus

55. Matches pressure chart

56. TYPES OF CLOUD