CLOUD FORMATION A STUDY IN METEOROLOGY Created by Joshua Toebbe NOHS 2015

CLOUD FORMATIONA STUDY IN METEOROLOGY

Created by Joshua Toebbe NOHS 2015

WHAT ARE CLOUDS?

• WELL, WHAT ARE THEY?

• ITS SIMPLE… WATER!

• BUT ITS NOT QUIT THAT SIMPLE.


CLOUD RECIPE

• TO HAVE A CLOUD YOU NEED THREE THINGS:

• WATER (IN VAPOR FORM)

• NUCLEATION SITES

• A DROP IN PRESSURE


CLOUD RECIPE

• OKAY LETS MAKE A CLOUD…REALLY…• WATER VAPOR (FROM HOT WATER)

• NUCLEATION SITES (SMOKE)

• AND A CHANGE IN PRESSURE (SQUEEZING A BOTTLE)


WATER VAPOR

• FOR CLOUDS TO FORM THEIR MUST BE WATER VAPOR IN THE AIR.

• FOR THIS TO OCCUR THEIR MUST BE ENOUGH ENERGY IN WATER PARTICLES TO BREAK FREE FROM THE SURFACE AND ENTER THE ATMOSPHERE (JUST LIKE WE TALKED ABOUT LAST TIME).

http://www.physics.lancs.ac.uk/research/condmatt/ult/cool.htm Created by Joshua Toebbe NOHS 2015

http://www.google.com/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&ved=0CAcQjRw&url=http://www.physics.lancs.ac.uk/research/condmatt/ult/cool.htm&ei=LIbWVMiLCYHtgwSpu4DQAg&bvm=bv.85464276,d.eXY&psig=AFQjCNHEiqGt6TmpB-iP6BGhzBC9bDSUTg&ust=1423431580908522



WATER VAPOR

• THERE IS ALWAYS A SMALL AMOUNT OF MOISTURE IN THE AIR.

• BUT FOR CLOUDS TO FORM THEIR MUST BE AN EXCESS OF THIS MOISTURE.

• THE RELATIVE HUMIDITY MUST BE SO HIGH THAT THE WATER VAPOR IS FORCED TO CONDENSE INTO TINY WATER DROPLETS.


WATER VAPOR

• WE KNOW THAT HUMIDITY AND TEMPERATURE ARE INVERSELY RELATED.

FOR RELATIVE HUMIDITY TO RISE, TEMPERATURE MUST

FALL.

http://earthobservatory.nasa.gov/Features/WaterVapor/


WATER VAPOR

• SO FOR THE HUMIDITY TO RISE, THE TEMPERATURE MUST FALL.

• AND WITHIN THE TROPOSPHERE WHAT HAPPEN TO THE TEMPERATURE AS ALTITUDE INCREASES?

• THAT’S RIGHT, IT DROPS!

• TEMPERATURE FALLS AS ALTITUDE INCREASES.

http://www.windows2universe.org/earth/Atmosphere


WATER VAPOR

• HAVE YOU EVER NOTICED THAT CLOUDS GENERALLY HANG OUT AT THE SAME ALTITUDE (OR AT LEAST IN ALTITUDE GROUPS)?

http://photography.nationalgeographic.com/photography/


WATER VAPOR

• THAT’S BECAUSE THE ALTITUDE AT WHICH THEY FORM, IS THE ALTITUDE AT WHICH THE PRESSURE AND TEMPERATURE PERSUADE WATER VAPOR TO CONDENSE.


WATER VAPOR

• THIS ALTITUDE IS KNOWN AS THE LIFTED CONDENSATION LEVEL.

• IT CHANGES FROM DAY TO DAY, AND SOMETIMES EVEN DURING THE DAY, BUT IT IS WHERE ALL THE CLOUDS LIKE TO HANG OUT.


WATER VAPOR

• WHY IS THIS?

• BELOW THE LCL, WATER DOES NOT CONDENSE, SO THERE ARE NO CLOUDS AT LOWER ALTITUDES.

• ABOVE IT THE WATER HAS ALREADY CONDENSED, SO THERE IS NO MORE WATER TO MAKE CLOUDS.

• AS A RESULT, THE CLOUDS CLUSTER AROUND THE LCL.


WATER VAPOR

• THERE CAN BE MULTIPLE LCLS IN A SINGLE DAY.

• THE RELATIONSHIP BETWEEN TEMPERATURE, PRESSURE, ALTITUDE AND HUMIDITY IS A COMPLICATED ONE.

• AND THE CONDITIONS ARE ALWAYS CHANGING.

• THIS IS WHY WE CAN HAVE CLOUDS AT DIFFERENT ALTITUDES.


WATER VAPOR

• BUT EVEN THEN, THE CLOUDS GROUP AROUND THEIR PERSPECTIVE LCL.

http://www.rgbstock.com/bigphoto/nFXjxCc/above+and+below3Created by Joshua Toebbe NOHS 2015

NUCLEATION

• WATER DOESN’T JUST CONDENSE ON ITS OWN. AT LEAST NOT WITHOUT A MUCH GREATER DROP IN TEMPERATURE ANY WAY.

• SO THE WATER VAPOR MOLECULES NEED SOMETHING TO HANG ON TO AS THEY JOIN TOGETHER.

• THESE ARE KNOWN AS NUCLEATION SITES.


NUCLEATION

• NUCLEATION SITES GIVE THE MOLECULES A MEETING PLACE SO THEY CAN FORM DROPLETS.

• THESE COULD BE SMALL PARTICLES OF DUST, SEA SALT BEING BLOWN ABOUT IN THE AIR, SMOKE, SAND PARTICLES, ANYTHING REALLY.

• THEY JUST HAVE TO BE SMALL ENOUGH TO BE CARRIED BY THE WIND INTO THE ATMOSPHERE.


PRESSURE

• FINALLY WE REACH OUR LAST INGREDIENT: A DROP IN PRESSURE.

• DO YOU RECALL WHAT CAUSES ATMOSPHERIC PRESSURE?


PRESSURE

• PRESSURE IS A MEASURE OF FORCE PER AREA.

• THE FORCE IS BEING GENERATED (IN THIS CASE), BY THE WEIGHT OF THE ATMOSPHERE ABOVE GROUND LEVEL.

http://voices.nationalgeographic.com/


http://www.google.com/url?sa=i&source=images&cd=&cad=rja&uact=8&ved=0CAgQjRw&url=http://voices.nationalgeographic.com/2013/07/20/exosuit-ads-the-no-pressure-premise/&ei=n4zWVJy8O-_bsATwk4HwCQ&psig=AFQjCNE5oOtFra6Lmgu3qpitKdgRgp-__A&ust=1423433248090140

PRESSURE

• THE MORE AIR THAT IS THERE, THE GREATER THE PRESSURE, THE LESS AIR THAT IS THERE, THE LOWER THE PRESSURE.

• SINCE THE THICKNESS OF THE ATMOSPHERE DOESN’T REALLY CHANGE.

• THIS “EXTRA AIR” COMES FROM THE CONVECTION CURRENTS IN OUR ATMOSPHERE.


PRESSURE

• UNEVEN HEATING OF THE EARTHS SURFACE PRODUCES CONVECTION CURRENTS.

• THESE REGIONS OF RISING AND FALLING AIR HAVE THE SAME THICKNESS.

• BUT THEY GENERATE DIFFERENT PRESSURES.


PRESSURE

• FALLING AIR IS BEING PUSHED BACK TOWARD THE GROUND AND THUS GENERATES A HIGHER PRESSURE ZONE.

• RISING AIR IS CHARACTERIZED BY A LOW PRESSURE REGION. THE AIR IS BEING LIFTED OFF THE GROUND, REDUCING ITS (WEIGHT) FORCE ACTING ON THE EARTH.


PRESSURE

• RECALL THAT FOR CLOUDS TO FORM THE AIR MUST GET COOLER.

• THIS IS MOST OFTEN ACHIEVED BY INCREASING ALTITUDE WITHIN THE TROPOSPHERE.

• IF THE PRESSURE IS HIGH, THE AIR CAN NOT RISE. RATHER IT IS FORCED BACK TOWARD EARTH.

• IF THE PRESSURE IS LOW, THE AIR CAN RISE, AND CLOUDS CAN FORM.


PRESSURE

• THIS RELATIONSHIP PRODUCES A NICE BUT COUNTERINTUITIVE WAY OF PREDICTING WEATHER. IF BAROMETRIC PRESSURE IS FALLING, PRECIPITATION IS PROBABLY COMING (SINCE CLOUDS ARE FORMING IN THE RISING AIR)

• IF BAROMETRIC PRESSURE IS RISING, THE SKY WILL BE CLEAR AND NO PRECIPITATION OCCURS (SINCE THE AIR IS FALLING AND CLOUDS CANNOT FORM).


WEATHER PREDICTION

• BAROMETRIC PRESSURE IS EASILY MEASUREABLE, AND PROVIDES A WONDERFUL TOOL FOR PREDICTING WEATHER.

• NOTE: IT DOESN’T REALLY MATER WHAT THE PRESSURE IS, JUST THE DIRECTION ITS GOING IN (UP OR DOWN).


WEATHER PREDICTION

• SO LETS TAKE A LOOK AT A SPECIFIC SITUATION. THE MEASUREMENTS FROM LAST WEEK. (2/1-2/7, 2015)

DATA FROM LOCALCONDITIONS.COM

Day Sunday Monday

Tuesday

Wednesday

Thursday

Friday Saturday

Pressure(in-Hg)

29.59

30.19

30.35

30.04 30.49

30.35

29.90

Trend(Arrow) Created by Joshua Toebbe NOHS 2015

CLOUD FORMATION

29

29.2

29.4

29.6

29.8

30

30.2

30.4

30.6Last Weeks Barametric Pressure

Barm

etr

ic P

ressu

re

(in

Hg

)

Sund

ay

Mon

day

Satu

rday

Satu

rday

Tues

day W

eden

sd

ay

Thur

sday

Frid

ay


CLOUD FORMATION

29

29.2

29.4

29.6

29.8

30

30.2

30.4

30.6Last Weeks Barametric Pressure

Barm

etr

ic P

ressu

re

(in

Hg

)

Sund

ay

Mon

day

Satu

rday

Satu

rday

Tues

day W

eden

sd

ay

Thur

sday

Frid

ay


SOURCES

• NEWMAN, L. (DEC. 15, 2006) MOISTURE, STABILITY AND PRECIPITATION. RETRIEVED FEB. 7, 2015 FROM HTTP://WEB.GCCAZ.EDU/~LNEWMAN/GPH111/TOPIC_UNITS/MOISTURE/MOISTURE_STABIL_PREC/MOISTURE_STABIL_PREC2.HTML

• RIEBEEK, H. (MARCH 15, 2004) WILL RUNAWAY WATER WARM THE WORLD? RETRIEVED FEB. 7, 2015 FROM HTTP://EARTHOBSERVATORY.NASA.GOV/FEATURES/WATERVAPOR/PRINTALL.PHP


http://web.gccaz.edu/~lnewman/gph111/topic_units/moisture/moisture_stabil_prec/moisture_stabil_prec2.html



http://earthobservatory.nasa.gov/Features/WaterVapor/printall.php



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CLOUD FORMATION A STUDY IN METEOROLOGY Created by Joshua Toebbe NOHS 2015