Precipitation

Precipitation

All types of moisture reaching the surface of Earth from atmosphere.

• Climate

• Geography

Factors determining precipitation or the amount of atmospheric moisture over a region

Ocean Surface

is the chief source of moisture for precipitation

• Dew

• Mist

• Fog

• Rain

• Hail

• Snow

Forms of Precipitation

Rain

the most common type of precipitation in our atmosphere. ___ is when liquid droplets fall to the surface of the Earth.

• Showers

• Drizzles

Two types of Rain forms

Showers

are heavy, large drops of rain and usually only last a period of time.

Drizzles

usually last longer and are made up of smaller droplets of water.

2.5 mm/hr

Light Rain

2.8 to 7.6 mm/hr

Moderate Rain

>7.6 mm/hr

Heavy Rain

Fog

a cloud that has formed near the surface of the Earth.

• Radiation Fog

• Advection Fog

• Upslope Fog

• Evaporation Fog

Four main types of Fog

Dew

The small drops of water which can be found on cool surfaces like grass in the morning.

Dew

This is the result of atmospheric vapor condensing on the surface in the colder night air.

Dew Point

is the temperature in which condensation starts to take place or when dew is created.

MIst/Drizzle

a bunch of small droplets of water which are in the air. This occurs with cold air when it is above a warm surface, for example water.

Fog

If you cannot see 1 kilometer or less you know you're dealing with ___.

• Convective

• Convergence

Formation of precipitation

Convective

system resulting from unequal Radiative heating

Convergence

formation of precipitation caused by Orographic barriers

Cyclonic Precipitation (Frontal/Non-frontal)

___________ results when the leading edge( front) of  a warm air mass meets a cool air mass. The warmer air mass is forced up over the cool air. As it rises the warm air cools, moisture in the air condenses, clouds and precipitation result.

Convective Precipitation

results from the heating of the earth's surface that causes air to rise rapidly. As the air rises, it cools and moisture condenses into clouds and precipitation.

Orographic Precipitation

It results when warm moist air of the ocean is forced to rise by large mountains. As the air rises it cools, moisture in the air condenses and clouds and precipitation result on the windward side of the mountain while the leeward side receives very little.

• Rain Gauges

• Snow Gauges

• Radars

• Satellites

• Scratching of snow packs

• Water equivalent in snow packs

Measurements Methods

Rain Gauges

are most commonly used for the measurement of precipitation, both in terms of rain fall and snow.

• Non recording rain gauges

• recording rain gauges

Types of Rain Gauges

Non-recording rain gauges

It is a rain gage which does not provide the distribution of amount of precipitation in a day. It simply gives the amount of precipitation after 24 hours (daily precipitation).

Recording rain gauges

These rain gauges are also called integrating rain gauges since they record cumulative rainfall. In addition to the total amount of rainfall at a station, it gives the times of onset and cessation of rains (thereby gives the duration of rainfall events)

• Float type

• Tipping bucket type

• Weighing type

Types of Recording rain gauges

Tipping Bucket type

A ___________ rain gauge is used for measurement of rainfall. It measures the rainfall with a least count of 1 mm and gives out one electrical pulse for every millimeter of rainfall

Weighing type gauges

It consists of a storage bin, which is weighed to record the mass. It weighs rain or snow which falls into a bucket, set on a platform with a spring or lever balance. The increasing weight of the bucket and its contents are recorded on a chart. The record shows accumulation of precipitation.

Float recording gauges

The rise of float with increasing catch of rainfall is recorded. Some gauges must be emptied manually while others are emptied automatically using self starting siphons.

Weather Radar

used to locate precipitation, calculate its motion, estimate its type (rain, snow, hail, etc.), and forecast its future position and intensity, can be analyzed to determine the structure of storms and their potential to cause severe weather. 

Weather Satellite

a type of satellite that is primarily used to monitor the weather and climate of the Earth.

Double Mass Curve Analysis

It is used to check the consistency of many kinds of hydrologic data by comparing date for a single station with that of a pattern composed of the data from several other stations in the area

• P = Precipitation (input to the system)

• ET = Evapotranspiration (loss due to evaporation + plant transpiration)

• Q = Runoff (surface + subsurface outflow)

• changeS = Change in Storage (soil moisture, groundwater, surface storage)

P = ET + Q + changeS

Water Budget formula