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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Shape and size of the earth
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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Shape and size of the earth
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
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