1. Climatology
We talk about climatology b/c it has so much to do with the activity of
our tree. We need to understand some of the basics so that we
can discuss in more detail how they affect the productivity of that tree

2. Montana Water Desert Tropical forest Tundra Boreal (Temperature)
Energy
MT is in a climate transition area for both energy and water.

3. Elevation also plays a big role as it affects both T and PPT.

4. Climate vs. Weather Climate Weather Microclimate
characteristic patterns, means, and extremes of weather (usually a 30-year period is chosen)
Weather
local short-term atmospheric conditions
Microclimate
local variation in climate
Climate – characteristic patterns, means, and extremes of weather
Weather – local short-term atmospheric conditions
Microclimate – local variation in climate, influencing spatial patterns of local
ecosystems and their species composition; especially influential in maintaining
some species near the limit of their ranges.
Climate is a major factor in:
Genetic differentiation and speciation
Species distributions
Growth rates
Carbon balance
Variation in climate with latitude, elevation and proximity to large water bodies
and mountain ranges is closely tied to distribution of vegetation on global,
regional, and local scales.
Characteristic temperature and precipitation patterns, as they interact with
vegetation, parent materials, and physiographic position, are important in
determining soil processes and soil development.
Long-term changes in climate have continuously altered the spatial distribution and
species composition of forested ecosystems globally. Both natural and
anthropogenic changes in climate could potentially alter the distribution of forests and
their productivity in the future.

5. Missoula, MT Lat/Lon 46.92,-114.08 Elevation 3,220 Feet Temperate Coniferous Forest
Precipitation
Period of Relative Drought
Precipitation
Temperature
Temperature

6. Jackson, MS Lat/Lon 32.32, -90.08 Elevation 283 Feet Subtropical Pine Forest
Precipitation
Precipitation
Temperature
Temperature

7. Flagstaff, AZ Lat/Lon 35.13, -111.67 Elevation 6,894 Feet Dry Mixed Conifer Forest
Precipitation
Precipitation
Period of
Relative
Drought
Temperature
Temperature

8. Kit Carson, CO Lat/Lon 38.45, -102.47 Elevation 4,285 Feet Temperate Grassland
Precipitation
Period of
Relative Drought
Temperature
Precipitation
Temperature

9. Lansing, MI Lat/Lon 42.77, -84.60 Elevation 828 Feet Temperate Mixed Forest
Precipitation
Precipitation
Temperature
Temperature

10. Radiation & Temperature

11. Insolation: Solar Radiation Striking the Earth’s Surface
I = insolation
S ~ 1000 W m-2 (clear day solar insolation on a surface
perpendicular to incoming solar radiation.
This value actually varies greatly due to
atmospheric variables.)
Z = Zenith Angle (the angle from the zenith (point directly
overhead) to the Sun’s position in the sky)
The zenith angle is dependent upon
latitude, solar declination angle, and time
of day.
We discuss radiation because it provides the energy used by plants.
The zenith angle is the angle between directly overhead and the sun.
I = S cos(Z)

12. Insolation: Zenith Angle
Z = cos-1 {sin(Latitude) * sin(Solar Decl.) +
cos (Latitude) * cos(Solar Decl.) * cos H}
Latitude = latitude at site of interest (Missoula ~46°)
Solar Decl. = solar declination; the latitude on the earth where
the sun is directly overhead at solar noon.
At Vernal Equinox (Mar. 21/22) = 0°
At Summer Solstice (Jun. 21/22) = +23.5°
At Autumnal Equinox (Sept. 21/22) = 0°
At Winter Solstice (Dec. 21/22) = -23.5°
H = hour angle = 15° x (Time – 12)
This is the angle of radiation due to the time of day
Time is given in solar time as the hour of day from
midnight.
This equation is how we determine the zenith angle.
It depends on your latitude and the solar declination.
+23.5 is Tropic of Cancer.
solar declination: the latitude on Earth where the sun is directly overhead at solar noon

13. Light is most concentrated from an overhead source
Light hitting at an angle is less concentrated

14. Why are there seasons? Basically, it is because the Earth is tilted at 23.5°.
At the Vernal and Autumnal Equinox, energy hits the Earth equally in both hemispheres.
At the summer solstice, incoming solar energy is greatest in the Northern Hemisphere (sun is perpendicular to Earth at the Tropic of Cancer).
At the winter solstice, incoming solar energy is greatest in the Southern Hemisphere (sun is perpendicular to Earth at the Tropic of Capricorn).
The Arctic Circle defines the circle on the earth above which, on December 21, the sun doesn’t rise above the horizon.
The Antarctic Circle defines the point on the earth above which, on June 21, the sun doesn’t rise above the horizon.
In the tropics,there is no real change in daylength => no real change in incoming energy => no seasonal change in temperature.
Seasonality comes from the monsoon season.
June-September in India
November-April in Australia

15. Daylength

17. Electro-magnetic Spectrum
Energy is a spectrum of which we can only see a very small part.

18. Important Radiation Laws & Concepts
Stefan-Boltzmann Law
E =   T4
Everything above absolute 0 (0K) emits energy at a rate to the 4th power of its temperature.
So, if it is warmer, it emits much more energy. Since it is at the 4th power, the relationship
Shoots up quickly as the temperature increases. It is easy to see why the sun (6000K) (hot) emits much
more than the earth (300K).

19. Solar radiation Earth radiation
We are primarily concerned with two types of radiation – the short-wave (visible/nearIR) from the sun and the thermal (long-wave) from the earth.
We need to think of this as a spectrum. A good example is a wood stove in a dark room.
Notice that much of the radiation from the sun is in the visible and near infrared range. In fact, about ½ of all of the energy from the sun is in the visible, also called Photosynthetically Active Radiation (PAR).
Earth radiation

20. Radiation Radiation Conduction Convection
There are 3 ways in which energy transfer occurs:
Radiation – transfer through the air (e.g., sun)
Conduction – transfer along/between objects (e.g., touch a hot poker)
Convection – movement caused by convective air movement (e.g., thermals from a stove)
When it is cold, you don’t feel or see any thermal energy coming from it. As you begin to pile on the logs, though, you can start feeling the energy. If you keep adding logs, then it will eventually start to glow a reddish tint.
If you switch to coal, it can eventually get white-hot (visible), but then, you’d better leave, b/c your house is about to explode!

25. Important Radiation Laws & Concepts
Wien’s Law
m (m) = 2897 / T
Wien’s law explains the relationship between the temperature and the wavelength of an object.
So, for the earth, temperature is 300 K, meaning the wavelength is ~ 10 microns.
The sun has a T = 6000K, so it’s wavelength is ~0.5 microns
m  wavelength of maximum intensity;
the higher the temperature,
the shorter the wavelength &
the more intense the light

26. Also, from Wien’s Law, the hotter the object, the more intense the light.
Wien's Law tells us that objects of different temperature emit spectra that peak at different wavelengths.
Hotter objects emit most of their radiation at shorter wavelengths; hence they will appear to be bluer .
Cooler objects emit most of their radiation at longer wavelengths; hence they will appear to be redder.
Furthermore, at any wavelength, a hotter object radiates more (is more luminous) than a cooler one.
m (m) = 2897 / T

27. So simple addition and subtraction.
What comes in – what goes out = what is left for work
And, Missoula has more energy than Seattle b/c of less atmosphere even if all other conditions are the same.

28. Important Radiation Laws & Concepts
Net radiation for a tree
Rn = incoming – outgoing
Rn = (1- )Is + EL T4(surface) -  T4(sky)
 is albedo, which is the
reflectivity of a surface
fresh snow has a high albedo (0.9)
dark forest has a low albedo (0.05 – 0.15)
light colored soils are in between (0.4 – 0.5)
mean albedo for earth  0.36
Here is what happens to our tree energy-wise.
Total incoming =
direct shortwave radiation from the sun,
diffuse shortwave radiation from the sky,
reflected shortwave radiation from nearby surfaces,
longwave radiation from atmospheric emission,
longwave radiation from nearby surfaces.
Total outgoing = longwave radiation from the surface
Photosynthesis <1% of total incident shortwave solar radiation, so we ignore it.

29. Thermal Radiation From Atmosphere Reflected Sunlight Transfer by
Reradiation
Direct
Sunlight
Transpirational
Transfer
Scattered
Sunlight
wind
Convective
Transfer
Here is what happens to our tree energy-wise.
Total incoming =
direct shortwave radiation from the sun,
diffuse shortwave radiation from the sky,
reflected shortwave radiation from nearby surfaces,
longwave radiation from atmospheric emission,
longwave radiation from nearby surfaces.
Total outgoing = longwave radiation from the surface
Thermal
Radiation
Reflected
Radiation

30. Important Radiation Laws & Concepts
Surface Energy Balance
Rn – G = H + E
This just summarizes some of our basic equations.
First, net radiation = what comes in – what goes out
represents what is available for work
Energy balance
available energy is lost in 2 main ways:
sensible heat
evaporation
PSN represents <1% of all available energy,
so we ignore it.
Bowen Ratio
 = H / E

31. Bowen Ratio  = H / E  = 10 / 1 = 10  = 10 / 100 = 0.1
Now, scientists have come up with a way to determine which of the two
ways of energy loss is dominated – Bowen ratio
Think of a parking lot – really hot. This is because most of the heat is used to
heat up the parking lot
The lake is much cooler, ~90% of the energy is used to evaporate water from
the surface.
While the parking lot will warm tremendously in one afternoon, the lake will
take months to warm up (Flathead Lake from 32F [mid-April]
to 76  F [late July]).
 = 10 / 1 = 10
 = 10 / 100 = 0.1

32. White box = “official temperature” (34°C = 93°F)
Decayed log – dark, but very wet, well-connected to surface
Humus
Litter so hot – dry, dark, little heat conductivity to surface
Charred surface – even hotter (poor connection to soil, very low thermal conductivity.
Residue – little more water content than litter
Bare Soil – thermal connectivity
To get a maximum temperature at Lubrecht, need all of these:
High radiation
No wind
Dry Surface
If it is cloudy, windy, rainy, the box is a good indicator of surrounding temperature

33. White box = “official temperature”
Decayed log – wet, connected to surface, loses energy slowly
Humus
Residue
Litter – dry, little connection to surface, loses energy quickly
Drier surface gets hotter during the day and cooler at night.
These are reasonable estimates for the area. On a cloudy day, will be cooler (70-80 °F) & nights warmer, and wind also has an effect.
Think of the impact on seedlings:
Protein denaturation at ~53°C

35. Here are temperatures for the same area
daytime, not much difference
nighttime, about 15C warmer just upslope from valley
think about this when backpacking
Again, cold air drainage at night – cold air denser, so
sinks, settles in the bottoms – like water

36. Take what we learned and put it on a slope
Not much difference on hillside regardless of
silvicultural practice – all about 1 month
later than valley
Example of cold air drainage – occurs in Missoula about
half the time during the 6 months of “winter”

37. Gstettneralm Sinkhole, Austria Elevation = 1270 m 21 January 1930
-1.8°C
-3.7°C
150 m
+2.3°C
-1.1°C
-12.4°C
-15.6°C
-28.8°C
All time temperature difference record!
Small valley in Switzerland – vertical distance from here to the “M”
At top of valley – about 1C (34 F),
as go into valley, -30C (30 BELOW ZERO!!) (-22 F)
extreme case of cold air drainage!
Gstettneralm Sinkhole, Austria
Elevation = 1270 m
21 January 1930
Coldest temperature = °C (-63 °F)
Photo: Bernhard Pospichal,
November 2001

38. Heat Distribution (Global Atmospheric Circulation)
Simple, single cell atmospheric convection in a non-rotating Earth.  "Single cell" being either a single cell north or south of the equator. Figure 7.5 in The Atmosphere, 8th edition, Lutgens and Tarbuck, 8th edition, 2001.
Driven by the thermal contrast between the poles and tropics
The intuitive meridianal circulation is then as in picture.
But the real world rotates and has continents, oceans and mountain ranges, so…..

39. Heat Distribution (Global Atmospheric Circulation)
An intermediate model: We now allow the earth to rotate.  As expected, air traveling southward from the north pole will be deflected to the right. Air traveling northward from the south pole will be deflected to the left.
However, by looking at the actual winds, even after averaging them over a long period of time, we find that we do not observe this type of motion.  In the 1920ís a new conceptual model was devised that had three cells instead of the single Hadley cell.  These three cells better represent the typical wind flow around the globe.
Idealized, three cell atmospheric convection in a rotating Earth.  "Three cell" being either three cells north or south of the equator.  The deflections of the winds within each cell is caused by the Coriolis Force. Figure 7.5 in The Atmosphere, 8th edition, Lutgens and Tarbuck, 8th edition, 2001.

40. The Coriolis Force Play Coriolis Force Movie Legend:
Blue = Inertial Path
Red = Path on rotating turntable
Gray = Path on stationary turntable

41. Heat Distribution (Global Atmospheric Circulation)
An intermediate model: We now allow the earth to rotate.  As expected, air traveling southward from the north pole will be deflected to the right. Air traveling northward from the south pole will be deflected to the left.
However, by looking at the actual winds, even after averaging them over a long period of time, we find that we do not observe this type of motion.  In the 1920ís a new conceptual model was devised that had three cells instead of the single Hadley cell.  These three cells better represent the typical wind flow around the globe.
Idealized, three cell atmospheric convection in a rotating Earth.  "Three cell" being either three cells north or south of the equator.  The deflections of the winds within each cell is caused by the Coriolis Force. Figure 7.5 in The Atmosphere, 8th edition, Lutgens and Tarbuck, 8th edition, 2001.

42. Horse Latitudes Around 30°N we see a region of subsiding (sinking) air
Horse Latitudes Around 30°N we see a region of subsiding (sinking) air.  Sinking air is typically dry and free of substantial precipitation. Many of the major desert regions of the northern hemisphere are found near 30° latitude.  E.g., Sahara, Middle East, SW United States.
Doldrums Located near the equator, the doldrums are where the trade winds meet and where the pressure gradient decreases creating very little winds.  That's why sailors find it difficult to cross the equator and why weather systems in the one hemisphere rarely cross into the other hemisphere.  The doldrums are also called the intertropical convergence zone (ITCZ). Owing to the tilt of the Earth's axis in orbit, the ITCZ will shift north and south.  It will shift to the south in January and north in July.
This shift in the wind directions owing to a northward or southward shift in the ITCZ results in the monsoons.  Monsoons are wind systems that exhibit a pronounced seasonal reversal in direction.  The best known monsoon is found in India and southeast Asia.
Winter -- Flow is predominantly off the continent keeping the continent dry.
Summer -- Flow is predominantly off the oceans keeping the continent wet.
Monsoons happen not only in southeast Asia and India, but also in North America.  They are responsible for the increased rainfall in the southwest US during the summer months and the very dry conditions during the winter months.

43. Clouds There are 3 ways that clouds form: convective
air mass frontal systems
orographic (mountains)

44. Convective Cloud Formation

45. Orographic Cloud Formation

46. Frontal Cloud Formation

47. 80 cal/gram
absorbed
540 cal/gram
absorbed
80 cal/gram
released
540 cal/gram
released

48. Adiabatic Lapse Rates 15°C 20°C 30°C Dry Adiabatic Lapse Rate:
10°C/1000 m
5.5°F/1000 ft
Saturated Adiabatic Lapse Rate:
6.5°C/1000 m
3.6°F/1000 ft
15°C
Lifting Condensation Level (Saturation Level)
20°C
“Normal” Environmental Lapse Rate:
6.5°C/1000 m
3.3°F/1000 ft
30°C

49. Vapor Pressure

50. Vapor Pressure Deficit
(VPD)

53. In the summer, the sun rises to the northeast of Missoula and sets to the northwest. So, do north-facing slopes near Missoula ever get direct sun? Yes, of course, during sunrise/sunset in the summertime.

54. Recorded
Dewpoint
Temperature (F)
09/30/05
Recorded
Minimum
Temperature (F)
09/30/05

55. Effects of Precipitation on the Carbon Balance of Mount Jumbo
Biggest slope effects are found in the Northern Rockies. Around Missoula, we can really see this near the “L” on Mount Jumbo. It is not an issue during the summer. But, during the winter, snow that falls on the south-facing slopes will melt – they will even have less snow than flat surfaces. On northern slopes, however, the snow piles up, increasing available moisture after snowmelt. Therefore, trees in this area grow on north-facing slopes since there is more moisture there. South-facing slopes get too hot and dry during the summer since there is no buildup of moisture to both support trees & evaporate to cool the area.

56. Longitudinal variations of. - precipitation (mm y-1),
Longitudinal variations of - precipitation (mm y-1), - temperature (oC), - vapor pressure deficit (kPa), and - rainfall fraction to precipitation (%) are averaged for each column for [A shaded graph shows column-mean elevation ( m) from the coast (Seattle) to the Rocky Mountain area (near Missoula).]
Range: Seattle to almost Missoula
Resolution: 1-km

57. Land Surface Temperature, Aug. 21, 2003 @ 6:14 p.m.
August 21, 6:14 p.m.
Min = C (-99.7F)
Max = 58.25C (136.85F)
Mean = 18.55C (65.40F)
Darker = Cooler

58. Land Surface Temperature
Wild Horse Island
Mission
Mountains
ASTER image draped over DEM
Cool tone = cool; Red = warm
July 2003, Flathead Lake

59. Land Surface Temperature