This presentation is dedicated to explain climate and climatic phenomenon which is made by pro. Neha arora

1. By
Dr. Neha Arora

6. What is Moisture ? A small amount of a liquid (such as water) that makes
something wet or moist Wetness caused by water; "drops of wet gleamed on
the window"
• Water is known to exist in three different states; as a solid, liquid or gas.
Clouds, snow, and rain are all made of up of some form of water. A cloud is
comprised of tiny water droplets and/or ice crystals, a snowflake is an
aggregate of many ice crystals, and rain is just liquid water.
•The solid state of moisture is represented by solid forms of precipitation –
snow – hail – sleet and tiny ice crystals - Solid state (e.g. ice) occurs at
temperature below freezing point .
•The liquid state of moisture consists of rain and of tiny drops of tiny
droplets of water that aggregate to form most clouds. Liquid state (e.g. sea
water) occurs between freezing and boiling point temperatures (0 degree C
– 100 degree C).
•Water existing as a gas is called water vapor. When referring to the amount
of moisture in the air, we are actually referring to the amount of water vapor.
If the air is described as "moist", that means the air contains large amounts
of water vapor - Gaseous state (e.g. water vapor) occurs at temperatures
100degree C or 212 degree F

7. Water’s Changes of State
• Liquid to Gas- Evaporation – is the process of changing a
liquid to a gas
•Gas to liquid -Condensation – is the process where a gas – like
water vapor – changes to a liquid - water
•Solid to Gas- Sublimation – is the conversion of a solid
directly to a gas without passing through the liquid state.
• Water vapour to solid- Deposition – is the conversion of
vapor directly to a solid

8. Water’s Changes of State Solid to Liquid The process of changing of state – such as
melting ice – requires that energy be transferred in the form of heat.
Latent Heat – is the energy absorbed or released during a change of state.

10. The Hydrological cycle The hydrological cycle predominantly involves the three
processes – evaporation, condensation and precipitation.
It is a gigantic system, energized by Sun, in which the vital link between lands
and oceans is provided by atmosphere. Briefly, it represents the continuous
movement of water from the oceans to the atmosphere, from atmosphere to the
landmasses, from landmasses back to the oceans.
Therefore, hydrological cycle represents interchanges of both physical state as
well as geographical positions. Indeed, the movement of water in this complex
hydrological cycle holds the key for distribution of moisture over the earth
surface (Figure 2).
Hydrological cycle is intricately related to all weather and climatic phenomena.

11. Water vapour in the atmosphere is derived through evaporation from the oceans
and seas, terrestrial lakes, land water bodies (tanks and ponds), rivers, and
icefields and glaciers.
These sources of moisture extend over about 75 per cent of the earth’s surface. In
addition to these sources, evaporation of soil moisture, transpiration from plants
and animal respiration also contribute moisture to the atmosphere.
Aridity, temperature and velocity of winds are the major determinants of the
amount and intensity of evaporation. The relationship is direct, which means the
high aridity, high temperature and high velocity of winds indicates higher rates
and amount of evaporation.
Evaporation from oceans is more as compared to continents. In continental
areas maximum evaporation occurs between 100N and 100 S latitudes. In case of
oceans, the latitudinal zone of 100 -200 latitudes in both the hemispheres
records maximum evaporation.However, land-sea moisture exchanges and
latitudinal moisture exchanges are common.
The prevailing winds, air masses, cyclones, and other atmospheric disturbances
play a very significant role in these moisture exchanges.

13. Evaporation is the process by which water changes from a liquid to a gas or vapor. Water boils
at 212 degrees F (100 degrees C), but it actually begins to evaporate at 32 degrees F (0 degrees
C); it just occurs extremely slowly. As the temperature increases, the rate of evaporation also
ncreases. The amount of evaporation depends on the temperature, and it also depends on
he amount of water there is to evaporate. For example, there is not much evaporation
occurring in the Sahara Desert, but why? Although it can get extremely hot in the Sahara, it's
ust sand - there's just not much water to be evaporated.
What is Evapotranspiration? Evapotranspiration is an important process in the water cycle
because it is responsible for 15% of the atmosphere’s water vapor. Without that input of water
vapor, clouds couldn’t form and precipitation would never fall. Evapotranspiration is the
combined name for the processes of evaporation and transpiration. When water vapor is
eleased into the atmosphere both processes are involved, so they have been combined into
one word to cover all bases. The evaporation in evapotranspiration refers to water evaporated
rom over land. This includes evaporation from soil, wetlands, and standing water from
places like roofs and puddles. It can also refer to direct evaporation of liquid water from the
eaf surface of the plant.
Transpiration happens when plants release water vapor from tiny holes, called stomata, in
heir leaves. This is caused in part by the chemical and biological changes that occur as the
plant undergoes photosynthesis and converts carbon dioxide into oxygen. Transpiration
performs the same function as human sweating because plants do it to cool down their
eaves.
23.

14. Factors that affect evapotranspiration:
Temperature – As temperature increases, the rate of evapotranspiration increases.
Evaporation increases because there is a higher amount of energy available to
convert the liquid water to water vapor. Transpiration increases because at warmer
temperatures plants open up their stomata and release more water vapor.
Humidity – If the air around the plant is too humid, the transpiration and
evaporation rates drop. It’s the same reason sweat does not evaporate from our
skin when it’s too humid. Wind speed – If the air is moving, the rate of
evaporation will increase. The wind will also clear the transpiration, so the plant
will increase its rate of transpiration.
Water availability – If the soil is dry and there is no standing water there will be no
evaporation. If plants can’t get enough water they will conserve it instead of
transpiring by closing their stoma. Soil type – Soil type determines how much
water soil can hold and how easy it is for the water to be drawn out of it, either by a
plant or by evaporation. For areas where the ground is covered by vegetation, the
rate of transpiration is considerably higher than the rate of evaporation from the
soil.
Plant type – Some plants, like cacti and other succulents, naturally hold onto
theirwater and don’t transpire as much.

15. What is Water Vapor? Water vapor is water in its gaseous state- instead of liquid
or solid (ice). Water vapor is totally invisible. If you see a cloud, fog, or mist, these
are all liquid water, not water vapor. Water vapor is extremely important to the
weather and climate. Without it, there would be no clouds or rain or snow, since
all of these require water vapor in order to
12. evaporates from the surface of the Earth eventually returns as precipitation -
rain or snow. Water vapor is also the Earth's most important green house gas,
accounting for about 90% of the Earth's natural greenhouse effect, which helps
keep the Earth warm enough to support life. When liquid water is evaporated to
form water vapor, heat is absorbed. This helps to cool the surface of the Earth.
This "latent heat of condensation" is released again
13. when the water vapor condenses to form cloud water. This source of heat helps
drive the updrafts in clouds and precipitation systems, which then causes even
more water vapor to condense into cloud, and more cloud water and ice to form
precipitation. It is restricted to the lower part of the troposphere – half of all
water vapor is found within 1.6 km of the earth’s surface and only a tiny fraction
exists above 6.4 km.