What do you know about Anchovies?

What do you know about Anchovies?

• In 1970 Peruvian anchovies accounted for about 10% of the total world fish catch.

• In 1972 the fishery collapsed

El Nino

El Nino Years

MoistureMoisture

Hydrosphere: The realm of water in all its forms

Hydrosphere: The realm of water in all its forms

• Most water in oceans 97.5%

• Most fresh water in glaciers

• Much more ground water than fresh surface water

• Very little in atmosphere at any one time

States of WaterStates of Water

• 3 states of water:– Solid (Ice)– Liquid (water) -– Gas (water vapor)

• Transformations– To more energetic state:

Latent Heat Absorbed• Evaporation

• Melting

• Sublimation

– To less energetic state: Latent Heat Released• Freezing

• Condensation

• Deposition

• 3 states of water:– Solid (Ice)– Liquid (water) -– Gas (water vapor)

• Transformations– To more energetic state:

Latent Heat Absorbed• Evaporation

• Melting

• Sublimation

– To less energetic state: Latent Heat Released• Freezing

• Condensation

• Deposition

HumidityHumidity• Amount of water

vapor in the air

• Humidity varies

dramatically all

over Earth

• Warm air can

hold much more

water vapor

than cold air

• Amount of water

vapor in the air

• Humidity varies

dramatically all

over Earth

• Warm air can

hold much more

water vapor

than cold air

HumidityHumidity

SaturationSaturation

• Saturation – when air can hold no more H2O↑

• Increases geometrically with temperature

• Saturation – when air can hold no more H2O↑

• Increases geometrically with temperature

Dew Point TemperatureDew Point Temperature

• Temperature at which air, when cooled,

becomes saturated

• Provides measure of actual moisture in air

• Curve is same as for saturation specific

humidity

• Also, a measure of human comfort

– Dew point temp > 70°F considered oppressive

• Temperature at which air, when cooled,

becomes saturated

• Provides measure of actual moisture in air

• Curve is same as for saturation specific

humidity

• Also, a measure of human comfort

– Dew point temp > 70°F considered oppressive

Relative HumidityRelative Humidity• What TV weather forecasters mean by “humidity”• Water vapor in air compared to maximum (saturation)

water vapor at that temperature • Relative Humidity (RH) • 50% RH means air has ½ maximum water vapor at that

temperature

• What TV weather forecasters mean by “humidity”• Water vapor in air compared to maximum (saturation)

water vapor at that temperature • Relative Humidity (RH) • 50% RH means air has ½ maximum water vapor at that

temperature

What is Heat?What is Heat?• Heat can be thought of as molecular motion. • The more motion….the more heat• Compressing or decompressing air can cause heating (compressing) or cooling decompressing.

– For instance…. as air rises, it expands and cools

• Heat can be thought of as molecular motion. • The more motion….the more heat• Compressing or decompressing air can cause heating (compressing) or cooling decompressing.

– For instance…. as air rises, it expands and cools

Adiabatic ProcessAdiabatic Process

• The idea is that with a parcel of gas if no

energy is added or subtracted, the

temperature will rise if it is compressed, and

fall if it expands

• As air rises in the atmosphere, it expands

and cools (since the air pressure drops)

• As air falls in the atmosphere, is contracts

and heats (Sana Anna winds, Chinooks)

• The idea is that with a parcel of gas if no

energy is added or subtracted, the

temperature will rise if it is compressed, and

fall if it expands

• As air rises in the atmosphere, it expands

and cools (since the air pressure drops)

• As air falls in the atmosphere, is contracts

and heats (Sana Anna winds, Chinooks)

Adiabatic ProcessAdiabatic Process

Air parcels cool at predictable rate as they rise:

– Dry (no condensation) adiabatic lapse rate -

10°C/1000m

– At lifting condensation level, saturation occurs

– Saturated (condensation occurring, heat released)

• Cloud forms as parcel rises

• Moist adiabatic lapse rate – 4-9°C/1000m

• Use 5°C/1000m as estimate of Moist adiabatic

rate

Air parcels cool at predictable rate as they rise:

– Dry (no condensation) adiabatic lapse rate -

10°C/1000m

– At lifting condensation level, saturation occurs

– Saturated (condensation occurring, heat released)

• Cloud forms as parcel rises

• Moist adiabatic lapse rate – 4-9°C/1000m

• Use 5°C/1000m as estimate of Moist adiabatic

rate

Precipitation ProcessesPrecipitation Processes

• Air expands & cools as it rises, but…– What makes it rise?

– 4 processes help air to rise and drive precipitation

• Orographic precipitation

• Convective precipitation

• Frontal precipitation

• Convergence

• Air expands & cools as it rises, but…– What makes it rise?

– 4 processes help air to rise and drive precipitation

• Orographic precipitation

• Convective precipitation

• Frontal precipitation

• Convergence

Orographic PrecipitationOrographic Precipitation• Moist air forced by wind over mtns

– As air is lifted, condensation & precipitation occur– Air passes mtn top & descends leeward side– This air is compressed and warms with no precipitation– The dry, leeward side is called a Rainshadow

• Moist air forced by wind over mtns– As air is lifted, condensation & precipitation occur– Air passes mtn top & descends leeward side– This air is compressed and warms with no precipitation– The dry, leeward side is called a Rainshadow

Rain ShadowRain Shadow

Orographic PrecipitationOrographic Precipitation

Convective Precipitation (what we are used to….)

Convective Precipitation (what we are used to….)

• Air pockets warm at surface & rise rapidly• As they rise, they cool• Air bubble stays warmer & rises• Bubble reaches dew point temp →

condensation

• Condensation forms clouds, releases heat• Bubble will be cooling much slower than

surrounding air• Bubble pushes high into troposphere, cools

more….. makes thunderstorms

• Air pockets warm at surface & rise rapidly• As they rise, they cool• Air bubble stays warmer & rises• Bubble reaches dew point temp →

condensation

• Condensation forms clouds, releases heat• Bubble will be cooling much slower than

surrounding air• Bubble pushes high into troposphere, cools

more….. makes thunderstorms

Convective Precipitation ExampleConvective Precipitation Example