m&g 2 geography meterology

8/7/2019 m&g 2 geography meterology

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WMO

WMO facilitates the free and unrestricted

exchange of data and information,

products and services in real or near realtime on matters relating to safety and

security of society, economic welfare and

the protection of the environment


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India Meteorological Department

It is an India Govt. organization,

responsible for meteorological

observations, weather forecasts anddetecting earthquakes

It is also responsible for forecasting

tropical cyclones in the Arabian sea and

the Bay of Bengal

The head office ofIMD is in New Delhi


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IMD organization

The dept. is headed by Director General ofMeteorology. There are a total of four junior

Additional Directors Generals at New Delhi and

one at Pune Additionally there are 20 DDGs, 10 of them

located in New Delhi

There are six regional meteorological centres,

each under a DDG. These centres are Mumbai,Chennai, New Delhi, Kolkatta, Nagpur andGuahati. There are also sub units in each statecapitals


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IMD history

After a tropical cyclone hit Calcutta in 1864, and

subsequent famines in 1866 and 1871 due to

the failure of the monsoons, it was decided to

set up meteorological organization under oneroof

H.F. Blanford was appointed the first

meteorological reporter to the Govt. ofIndia, in

1889 John Eliot was appointed the first DG of

observatories in Calcutta.


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IMD task

It undertakes observations,communications, forecasting and weatherservices

It exchange the global data

In collaboration with ISRO, the IMD alsouses the INSAT for weather monitoring

The IMD is also one of the six RegionalSpecialized Meteorological Centers withinthe World Weather Watch programme


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Storm warning signals

Weather reports based on satellite

pictures and observations from other

vessels may contain storm warnings The meteorological deptt. sends warnings

by means of high priority telegrams to port

officers whose ports are likely to be

affected by adverse weather


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Storm warning signals

The port officers display visual stormsignals on conspicuous masts speciallymeant for this purpose

The signals consists of black coloredcones and cylinders by day and red andwhite lights by night

The port officers also send words tofishing vessels and country crafts in theirrespective ports


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Introduction to geography

It is a science that studies the spatial

arrangement of things on the surface of

the earth resulting from a dynamic

interaction between human and nature

Geography uses information provided by

various disciplines, all the way from

nuclear physics to ancient history


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Introduction to geography

Geography means description of earth

The term was first used by Eratosthenes,

has now acquired the status of sciencethat explains the arrangement of various

natural and cultural features on the earth

surface

Geography is often called as mother of all

sciences


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Branches of geography

Systematic geography- a study of specificnatural or social phenomenon that gives rise tocertain spatial patterns & structures on the earth

surfaces.It has four parts

Physical geography- geomorphology (genetic study ofsoil forms), climatology, hydrology, soil geography

Biogeography- plant geography (distribution ofvarious forests and grasslands), zoogeography,

human ecology (study the changing human nature,relationship and its consequences for human life andliving), environmental geography (quality of livingenvironment and its implications for human life)


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Branches of geography

Human geography- study of location and

distribution of all such phenomenon fall

under the purview of human geography

Geographic methods and techniques- field

studies, cartography, quantitative

geography, spatial information system

(GIS, GPS, LIS)


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GIS

A geographic information system (GIS) is a system for

capturing, storing, analyzing and managing data and

associated attributes which are spatially referenced to

the earth. In the strictest sense, it is a computer system

capable of integrating, storing, editing, analyzing,

sharing, and displaying geographically referenced

information. In a more generic sense, GIS is a tool that

allows users to create interactive queries (user created

searches), analyze the spatial information, edit data,maps, and present the results of all these operations.


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Regional geography

It starts with spatial imprints of one or all the

systematic geographic processes discernable as

regions of different sizes

Region could be based on a single factor likerelief, rainfall, vegetation, per capita income,

literacy and so on

The main branches of regional geography are-

regional studies, regional analysis, regional

development and regional planning


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Parallel of latitude

Latitude is angular distance of a place

from the equator

Equator is an imaginary line drawn fromeast to west on earth in such a way that all

the points of the line placed in middle of

the earth and divide it into two equal half

parts. The distance of the equator is samefrom both the poles


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Parallel of latitude

Parallel of latitude- any imaginary line

drawn on the earth with parallel equator.

These are tropic of cancer..

On the basis of these parallel of latitude

the world climate can be divided into three


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Meridian of longitude

Imaginary lines drawn vertically joining North &

South poles together are called meridians of

longitude

All meridians of longitude are of equal lengthand they meet together at both the poles

It begins from Greenwich where British Royal

Observatory is situated (the distance from east

and west is equal and it fall exactly at halfway

mark


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Meridian of longitude

Any place would be denoted as 0E or0W

depending upon it lies east or west from

premeridian

For geographical location first determine

the grid of the place then determine the

position of place latitudinally and

longitudinally


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Shape and size of the earth

Earth is a inner planet of solar system. It islargest of inner planets and densest of all

The shape of earth is not perfectlyspherical, it is an oblate or flattened,spheroid or ellipsoid. It is flattened at thepoles and bulges some what south of theequator

The age of earth may range between 2- 5billion


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Equatorial circumference- 39843 km

Polar circumference- 39746 km

Polar diameter- 12639.84 km

Equatorial diameter- 12754 km

Mass- 598x 1027 g

Time of rotation- 23 hr 56 min. 4.09 sec

Period of revolution- 365 days 5 hr 48 min

45.51 sec


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Inclination of the axis- 23027

Orbital velocity- 29.8 km/ sec

Escape velocity- 11.2 km/sec Distance from sun-

(max.) Aphelion- 152 m km

(min.) Perihelion- 147 m km


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Earths movement

Galactic movement- movement of earth in

relation to sun and rest of solar system.

Movement is in orbit around the centre of the

milky way. This has little effect on changing ofenvironment of earth

Rotation- Earth rotation around an axis in

imaginary line passing through the centre of the

earth. Direction of rotation is eastwardanticlockwise opposite to the suns apparent

movement


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Earths movement

Rotation defines the movements of the zone of

day and night on the earths surface and

circulatory movement of the atmosphere

The velocity of atmosphere varies from place toplace (0 at poles and max. (1700 km/ hr) at

equator (at 600 latitude the velocity is half of

max.)

The line separating the light and dark halves are

called as circle of illumination


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Revolution

The earth revolve around the sun in an elliptical

orbit at an average distance of 1.49x 108 km in

orbital path. The distance varies from time to

time. During January 3, the sun is nearest andon July 4 it is farthest to the earth

Speed of revolution is 29.72 km/ sec. One

revolution takes 365 days 6 hrs

The earth moves around the sun in plane of

elliptic


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Revolution

The equator makes an angle of 23.50 with

the plane of elliptic

The earths axis has a constant angle ofinclination with a plane of elliptic and it is

66.50.


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Equinoxes

At two points mid way between thesolstices, a line from sun to earth isperpendicular to the inclination of earths

axis At this point the sun shines equally in both

the hemisphere

These are two; vernal and autumn On March 21, both the hemisphere are

equally inclined towards sun


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Equinoxes and solstices

On September 23, both the hemisphere areequally inclined towards the sun. The suns raysare vertical at equator

Solstices -These are places where the

inclination of earth is towards the sun. Thesepoints are very near to perihelion and aphelion.These are also of two types

Winter solstices- the sun with respect to the

earth is farthest south occurs just before a fewdays of perihelion (22 Dec.)


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Solstices

Summer solstices- when the sun with

respect to earth is farthest in north, occurs

just before a few days of aphelion. At that

time the sun is directly overhead at noon

in latitude 23.5 0 north


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Eclipses

It is caused by the fact that light travels in

a straight line producing clearly well

defined shadows of objects in its path.

These are of two types lunar and solar

eclipses

Lunar eclipse- when earth comes between

moon and sun and shut off the light of sunfrom falling on the moon


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Solar eclipses

Solar eclipses- when the moon comes

directly between sun and earth and

obstruct light from the sun falling upon

some portions of the earth & people in this

region can not see the sun


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Cartography

Study of map is called as cartography

Map is the graphic representation of all or

part of the earth surface on plane or flatsurface

Lad surveys, aerial photograph and other

sources are used for making maps. Map

use standardized colour and symbols to

present the data


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Map

Locating places in map- On the basis of

latitude & longitude by using direction,

numeric grids are used to locate the

places in map. The direction can be shown

by compass needle. In topographic maps,

magnetic north is also shown. When true

north and magnetic north are coincide, themap is set or oriented


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Map

Map scale- It is used to draw a map on a

seat of paper or on atlas page. It must be

reduced or scaled down

Scale is the ratio between distance on a

map & the corresponding true distance on

the ground. It can be expressed in three

way: verbal/ written, graphic andrepresentative fraction


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Map

Verbal/ written statements tells about the scale

Graphic- A horizontal line divided into section

that represent unit of measurement on the

ground in metric & imperial unit

RF- It is the ratio which means one cm on map

represent how many cm on the ground; RF=

distance on map/ distance on the ground


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Map projections

The earth can be most accurately represented

by globe (spherical scale model)

It is impossible to show the earth's surface with

absolute accuracy on a plane or a flat surface

It can be shown with relative accuracy by

transferring or projecting the curved lines of

latitude and longitude to the flat surface of map,

is known as map projection


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Map projections

Map projections may be two type-

homolographic where area is shown in

correct proportion & conformal or

orthomorphic where shape is shown

accurately

Both area and shape can not be shown

accurately in the same map but someprojections minimize these distortions


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Type of map projections

Map projections are of five type

Conical- the maps are constructed by

projecting a part of the globe on to a cone. The parallel of latitude around which the

cone is tangent to the globe is called the

standard parallel. All parallels are

concentric circles and all meridians arestraight lines


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Conical map projection


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Map projections

Bonne- it is the modified conical projection. It

has only one standard parallel, but each parallel

is truly divided, therefore it is an equal area

projection Conical projection with two standard parallels-

An area of a country with a large land mass can

be represented more correctly with two standard

parallels and it is represented by a conebisecting the surface of the globe


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Bonne map projection


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Cylindrical map projection


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Map projections

Cylindrical- constructed by projecting the

surface of the globe on to a cylinder. In

this the parallels and meridians intersect at

right angles at all latitude eg. Mercator

projection. It is true to scale only at the

equator and latitudes are further apart in

the higher latitudes. Wall maps andatlases use mercator projection maps


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Mercator map projection


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Map projections

Azimuthal- constructed by directly placing

on to a flat surface, a particular point such

as south or north pole. All the meridians

are straight & parallels are concentric eg.

Lamberts equal area projection


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Lamberts map projection

m&g 2 geography meterology

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