Introduction to Meteorology

158 Pages·1924·7.947 MB·English

by  A. K. Das, B. N. Srivastava

INTRODUCTION TO METEOROLOGY
BY
A. K. DAS, M.Sc. (Cal.), D.Sc. (Paris)
Indian Meteorological Service
AND
B. N. SRIVASTAVA, M.Sc.
Department of Physics Allahabad University
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CONTENTS
CHAPTER XII
METEOROLOGY
HISTORICAL AND GENERAL
I,
SECTION PAGE
1, Introduction 359
2, History of meteorology 360
3, The meteorological elements 363
II. METEOROLOGICAL INSTRUMENTS
MEASUREMENT OF TEMPERATURE
MEASUREMENT OF PRESSURE
11. Two types of barometers 369
12. Standard Fortin's barometer 369
13 The Kew pattern barometer 370
14. The aneroid barometer 370
15. Barograph 37-
16. Units 372
MEASUREMENT OF WIND
17. Wind 372
18. Wind vane 373
19. Velocity estimations, Beaufort scale 374
.......
20 Anemometers 375
21. Pressure-plate anemometer.... ... 375
22. Rotation anemometer H75
CONTENTS
CONTENTS III
SECTION PAGE
IV. THE HEATING AND COOLING OK THE ATMOSPHERE. SOLARRADIATION
55 Sources ofenergy ofthe atmosphere 400
56. Distanceofthe sun .... 401
57. Directness and duration of solar radiation 401
58. Variation of insolation with latitude and time . . . 402
59. Absorption by the atmosphere 404
60. Pyrheliometers 405
61. The solarconstant 406
62. Variation of solar constant 407
63 Effective radiation 407
64. Distribution of weatherelements 408
V. DISTRIBUTION OF TEMPERATURE
65. Vertical distribution of temperature , , 408
66. Troposphereand stratosphere 411
67 Physical explanation of the existence of the stratosphere . 412
68. Inversions .... 414
69. Distribution oftemperature over theglobe 414
70. Annual variations 415
71. Isothermal Charts 416
72. Diurnal variation of temperature 419
7B. Variation with latitude 420
74. Influenceof altitudeon diurnal variation of temperature . 420
VI DISTRIBUTION OF PRESSURE
75. Vertical distribution of pressure .... 421
76. Distribution of pressure in the stratosphere 428
77. Convective or adiabatic equilibrium 424
78. Diurnal variation of pressureon the earth's surface . . 426
79. Variation with latitude 426
80. Annual variation of pressure 427
81. Isobaric charts 427
82. Monthly isobaric charts 428
VII. WATERVAPOUR IN THE ATMOSPHERE
83. Distribution of watervapourin the lower atmosphere . . 430
84. Water vapour in the stratosphere .... 432
85. Diurnal and annual variation ofhumidity 432
86. Methods of causing condensation 43B

CONTENTS V
SECTION PAGE
116. Evolution of a depression 477
117. Theory of General circulation based on polar front theory . 480
118. Anticyclones of temperate zones 481
119. Tropical cyclones 482
120. Energy of cyclones and depressions 488
121. Thunderstorms 488
122. Tornadoes 492
128. Whirlwinds 493
124. Nor'westers of Bengal 493
XII. WEATHER FORECASTING AND WEATHER SERVICE
125. Weather forecasting 494
126. Long-range and short-range forecasts 495
127. Weather service , 496
128. Methods of forecasting 498
APPENDIX 501
INDEXOF CHAP. XII (METEOROLOGY) . 507

CHAPTER XII
METEOROLOGY*
HISTORICAL AND GENERAL
I.
1 Introduction. ' Meteorology ' is a branch of the larger
science of Geophysics, or Physics of the earth. It de*ls with
the phenomena which take place in the atmosphere surround-
ing the earth and has nothing- to do with meteors. It
is derived from a Greek word ra jiere'w/x*, meaning *' the
things above."
The Science of Meteorology is again subdivided into
numerous branches each dealing with a particular class of
atmospheric phenomena But the two important divisions
are Climatology and Dynamical Meteorology. Climatology deals
with climate in general, i.e., description of various
atmospheric phenomena over the globe, their study, inves-
tigation and speculation regarding their origin, as well
as their relation to one another, their influence on animal and
vegetable life, on public health, and also a proper estimation
of the influence of geographical and topographical conditions
on these phenomena. Dynamical meteorology consists
principally in the study of the general laws of motion of the
atmosphere, and the mode of formation and propagation of
storms, depressions, etc. Djnamical meteorology also includes
"thermodynamics of the atmosphere" which deals with the
application of the laws of heat to such topics as formation of
clouds, precipitation and study of general weather conditions.
These two branches will be chiefly treated in this book. But
we have, in addition, other branches such as the following:
(i) Meteorological Optics . . . which deals with such pheno-
mena as formation of haloes, corona, problems of visibility, etc.;
* We are deeply indebted to Mr. S. Basu of the Indian Meteorological
Departmentforhiskindly going through the manuscript of this chapter and
forhisvaluablecriticisms andsuggestions.
359