Compendium of Meteorology Class I and Class II Meteorological Personnel Synoptic Meteorology [1/3]

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INDEX

INDEX

INDEX

INDEX

INDEX

CONTENTS

&

............................................................. Introduction ............................................................. Section 1 - The Synoptic Method .......................................... Section 11 - Physical Properties o f the Lower Atmosphere ................. Section 111 - iarge Scale Synoptic Weather Systems .......................

F oreuo rd

*

xi xiii

1 85 183

*

SECTION 1 .THE SYNOPTIC METHOD Chapter 1 1.1 1.2 1.3

.WEATHER OBSERVATIONS

................................................ Variability of atmospheric parameters . Density and frequency of observations ..................................................... Surface synoptic stations ........................................ 1.3.1 Composition o f observations . Instrumentation .......... 1.3.2 Times of observation ................................... Historical review

1.3.3 1.4

6

7 7

Representativeness and accuracy o f observations

...................................... Methods of observation . Instrumentation ........... ... ... Times o f observation ...............................

1.4.1

8

1.4.4

1.7

6

8

1.4.3

1.6

5

Upper-air synoptic stations

1.4.2

1.5

3

Evaluation of radiosonde data tia1 heights

.

Computation of geopo en-

.......................................

............................. Meteorological satellites .......................... Speciol observing systems ..........................

...

........ ............. ............. .............

Representativeness and accuracy o f observa ions

Ocean weather stations

8 9 9 10 10 13

INDEX .iv . CONTENTS

&

1.8

............................... .............................................

1.7.1

Reconnaissance f l i g h t s

13

1.7.2

Balloons

13

1.7.3

Rockets

..............................................

World Weather Watch (WWW)

.

The G l o b a l Observing System (GOS)

14 14

Chapter 2 .DATA HANDLING AND PROCESSING 2.1

Coding. decoding. r e c o r d i n g 2.1.1

2.3 2.4 2.5 2.6

Surface r e p o r t f r o m l a n d s t a t i o n s

....................

..................... 2.1.3 Upper-air r e p o r t s .................................... Transmissión o f s y n o p t i c weather r e p o r t s ....................... World Weather Watch (WWW) . The G l o b a l Telecommunication System (GTS) .......................................................... P l o t t i n g o f weather r e p o r t s ; symbolism ........................ A u t o m a t i c data h a n d l i n g and p r o c e s s i n g by computer ............. World Weather Watch (WWW) . The G l o b a l Data-processing System ( GDPS) ......................................................... 2.1.2

2.2

....................................

Surface r e p o r t from sea s t a t i o n s

28 28 30 31

31

32 34 35 35

Chapter 3 -.ANALYTICAL TOOLS 3.1

3.2

3.3

................................................. 3.1.1 Map p r o j e c t i o n s ...................................... 3.1.2 Map s c a l e s ........................................... Wind sounding c h a r t s ........................................... Thermodynamic diagrams .........................................

Weather c h a r t s

37 39

40 41 42

......

44

..............

48

3.3.1

G r a p h i c a l o p e r a t i o n s on a thermodynamic diagram

3.3.2

V a r i a b i l i t y o f thermodynamic p r o p e r t i e s

Chapter 4 .SYNOPTIC ANALYSIS (OTHER THAN NUMERICAL) 4.1

F i e l d s o f atmospheric p r o p e r t i e s

4.2

Co-ordinate system

4.3

Scalar analysis

...............................

51

.............................................

52

................................................

53

INDEX - v -

CONTENTS

pose 4.4 4.5

4.6

4.7

......................................................

Gradients Property surfaces and topography 4.5.1 Slope and curvature of surfaces 4.5.2 Special lines and points in a topographic field 4.5.3 The topographic field of air pressure 4.5.4 The topographic field of air density (specific volume) 4.5.5 The topographic fields of temperature

............................... ...................... ...... ................

56 56 57 59

................

61 62

................................................ .......................... Graphical analysis ............................................. Vector analysis 4.6.1 Streamline/isotach analysis 4.7.1 4.7.2 4.7.3

55

...................................

Grqphical addition Graphical subtraction Graphical multiplication and division

................................

................

64 64 66 68 68 69

Chapter 5 .PRACTICAL ASPECTS OF SYNOPTIC WEATHER ANALYSIS 5.1 5.2 5.3

Annex

..................................................... Analysis of the composite surface chart ........................ Analysis of upper-air charts ................................... 5.3.1 Ranges of temperature and height ..................... 5.3.2 Absolute and relative topographics ...................

Continuity

................................................................ *

70

71 78 79 82 84

*

SECTION 11 .PHYSICAL PROPERTIES OF THE LOWER ATMOSPHERE Introduction

.............................................................

Chapter 1 .NORMAL FIELDS OF ATMOSPHERIC VARIABLES AT SEA-LEVEL 1.1 Temperature. northern hemisphere 1.1.1 1.1.2

............................... Winter (January) ..................................... Summer (July) ........................................

87

89

89

91

INDEX .vi .

CONTENTS

& 1.2

1.3

1.4

1.5 1.6 1.7 1.8 1.9

................................... 1.2.1 Winter (January) ..................................... 1.2.2 Summer (July) ......................................... Temperature. southern hemisphere ................................ 1.3.1 Winter (July) ......................................... 1.3.2 Sumner (January) ...................................... Pressure. southern hemisphere ................................... 1.4.1 Winter (July) ......................................... 1.4.2 Summer (January) ...................................... Pressure. northern hemisphere

.............. Temperaturg. annual march. northern hemisphere .................. Pressure. zonally averaged for both hemispheres ................. Pressure. annual march. northern hemisphere ..................... Relative humidity. northern hemisphere .......................... 1.9.1 Winter (January) ...................................... 1.9.2 Summer (July) .........................................

Temperature. zonally averaged for both hemispheres

94

94 94 96

97 97 100

100 100

101 103

104 107 109

109 111

Chapter 2 -.CROSS-SECTIONAL REPRESENTATION OF MEAN TEMPERATURE AND WINDS AT UPPER LEVELS; THE PLANETARY VORTICES; BAROCLINICITY 2.1 2.2 2.3

Introduction .................................................... Geopotential height. northern hemisphere ........................ Temperature. northern hemisphere ................................ 2.3.1 Winter (January) 2.3.2

2.3.3 2.3.4

2.4

2.5

Winds 2.4.1

...................................... Spring (April) ........................................ Summer (July) ......................................... Autumn (October) ...................................... ........................................................... Stratospheric and mesospheric wind systems. northern hemisphere

............................................ 2.4.2 Winds below 32 km altitude. both hemispheres .......... Baroclinicity ...................................................

113 114 117 117 119 121 122 123 123 125 128

INDEX

.v i i . CONTENTS

& Chapter 3 3.1

.STANDING WAVES IN

Zona1 cross s e c t i o n s o f t h e mean circum-polar vortex. n a r t h e r n hemisphere

133

3.1.1

133

3.1.2 3.1.3 3.2

3.3

3.4

THE MEAN PLANETARY VORTEX

....................................................... (January) ....................................... Summer ( J u l y ) .......................................... Summary ................................................ Winter

137

3.2.1

137

.................. 3.2.2 Southern hemisphere. w i n t e r ( J u l y ) ..................... 3.2.3 Northern hemisphere. summer ( J u l y ) ..................... 3.2.4 Southern hemisphere. summer (January) .................. Topographic mean f i e l d s o f zona1 wind component a t 200 mb, both hemispheres ...................................................... 3.3.1 Northern hemisphere .................................... 3.3.2 Southern hernisphere .................................... Northern hemisphere. w i n t e r (January)

....................... (January) .................. ( J u l y ) .....................

4.6

146 146

146

Northern hemisphere. w i n t e r

149

3.4.2

Northern hemisphere. summer

3.4.3

Southern hemisphere. w i n t e r ( J u l y )

154

3.4.4

Southern hemisphere.

154

.A I R MASSES

..................... summer (January) ..................

149

AND F R M S

Mean tropopause c o n d i t i o n s

4.5

143

3.4.1

4 .a

4.4

142

149

4.7

4.3

139

The s t r a t o s p h e r i c (30 mb) mean c i r c u l a t i o n

................................... The p r i n c i p a l f r o n t a l zones ...................................... P h y s i c a l p r o p e r t i e s o f a i r masses ................................ 4.3.1 Summary o f processes i n f l u e n c i n g a i r masses ............ Exchange o f m o i s t u r e and heat between ocean and atmosphere ....... R a d i a t i o n a l heot f l u x ............................................ The p o l a r f r o n t and p o l a r j e t (mean c o n d i t i o n s ) .................. The s u b t r o p i c a l f r o n t and s u b t r o p i c a l j e t (mean c o n d i t i o n s ) ......

4.2

136

Topographic mean f i e l d s o f g e o p o t e n t i a l h e i g h t . b o t h hemispheres

Chapter 4 4.1

135

The t h r e e p r i n c i p a l a i r masses

J

.......................................

155 160 161 164 165 169

170 174

177

INDEX .v i i i . CONTENTS

Annex

................................................................... *

181

*

SECTION 111 .URGE-SCALE SYNOPTIC WEATHER SYSTEMS

Introduction

............................................................

185

Chapter 1 .FEATURES OBSERVED ON SURFACE CHARTS

........

1.1

Sea-leve1 pressure poleward o f t h e s u b t r o p i c a l h i g h b e l t

1.2

Sea-leve1 pressure equatorward o f t h e s u b t r o p i c a l h i g h b e l t

.....

186 188

Chapter 2 .FEATURES OBSERVED ON UPPER-AIR CHARTS

.......... t h e s u b t r o p i c a l h i g h b e l t .......

2.1

T y p i c a l f e a t u r e s poleward o f t h e s u b t r o p i c a l h i g h b e l t

192

2.2

T y p i c a l f e a t u r e s equatorward o f

194

Chapter 3 .SPECIFIC SYNOPTIC-SCALE SYSTEMS 3.1

3.2

3.3

................................................ 3.1.1 Waves i n a b a r o t r o p i c a i r c u r r e n t ..................... 3.1.2 K i n e m a t i c p r o p e r t i e s .................................. Waves i n a b a r o c l i n i c c u r r e n t ......................... 3.1.3 . B a r o c l i n i c i n s t a b i l i t y ................................ 3.1.4 Observed s t r u c t u r e o f upper long waves .......................... 3.2.1 Scales ................................................ 3.2.2 T i l t .................................................. 3.2.3 Index changes ......................................... 3.2.4 Blocking ............................................... 3.2.5 C u t - o f f ...............................................

Upper long waves

The s t r u c t u r e o f t h e p o l a r f r o n t and t h e p e l a r j e t s t r e a m 3.3.1

Basic theory o f d i s c o n t i n u i t y surfaces

.......

................

197

197 200 203 205 208 208 208 208 209 209 214 215

INDEX

.ix . CMENTS

3.3.2 3.4

4.2 4.3

4.4

...................

The structure of the subtropical front and the subtropical jet

Chapter 4 4.1

Discussion of a model of the polar front and polar jet in mid-winter (northern hemisphere)

.EXTRATROPICAL

..

221 235

C?CLONES AN) ANTICYCLONES

................ Basic theoretical concepts of cyclonic development .............. The life cycle o f extratropical cyclones ........................ 4.3.1 The incipient and the nascent wcwe stages ............. 4.3.2 The main development stage ............................ 4.3.3 The. occlusion stage ................................... 4.3.4 Developments after the occluded stage .................

Geographical distribution and seasonal variation

Potential vorticity and meridional air motion

...................

240 243

246 246 256 266 270 272

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