Instrumentation and Monitoring Exam One

The Environmental questions you are likely to be addressing usually fall into one of what two categories?

1) Current Status

2) How Impact

How does a small paper ball dropping through the air differ from a similar piece of paper dropping as a flat sheet?

The not crinkled paper has fewer smaller eddies around it when compared to the paper ball.

Under what conditions of driving force and chaotic resistance can we accurately predict a natural phenomenon?

Big driving force in respect to chaotic

Besides the paper dropping through the air give an example of a diffuse driving force and large-scale chaotic turbulence?

Weather

If I drop a sheet of dense metal (e.g., lead) rather than paper, will the fall time be more or less predictable, and why?

The fall time will be more predictable because the larger mass will create a larger driving force

How are replicates defined, and what purpose do they serve?

Replicates are defined as being able to do something the exact same way multiple times. They allow for experiments to be repeated this proves if the results of an experiment or monitoring was a one off reading or if it is what is actually happening. It can help create theories.

List the elements of the hydrologic cycle. Do not include the driving forces

Precipitation, Evapotranspiration, Infiltration, Subsurface flow, Runoff, Transpiration, Base Flow

Via what path does most of the rainfall onto the land surface take in actually entering the ocean?

Streamflow/ Base flow

List the driving forces for the hydrologic cycle.

Solar Energy, Gravity, Earth rotation and Residual (uneven heating), Physiochemical

Which hydrologic cycle element acts as a valve, essentially controlling how fast the water moves?

Infiltration

Give an example of why it is important to think of the hydrologic cycle over the 3-D landscape, and not just at a point.

Base flow does not occur evenly

About what percentage of the earths fresh water is in the atmosphere at any time?

0.04%

What percentage of the earths precipitation falls on land?

About 10%

About what portion of the rain falling on lush vegetated land ends up as evapotranspiration?

1/2

Explain why a small hydraulic radius means that you will have a slower flow in your channel

There will be more water in contact with rough spaces

Describe (no need for values) what is meant by the solar constant.

The amount of solar radiation at the outer edge of the atmosphere

Why do we get more solar radiation in Knoxville in June than hits the Equator?

Earth Tilt causes more hours of sunlight in Knoxville

About what portion of the incoming sunlight actually makes it to the earths surface?

47%

The area north of the Arctic Circle gets far more hours of sunlight (24 hours) during June than we get in Knoxville.

Why does that area actually get less total solar radiation?

Angle of the Sunlight

What are the two main causes of general wind patterns?

Differential heating (Thermal Variation) and Earth Rotation

Describe the general diurnal wind pattern (high- and low-velocity times) for inland areas

Earth Rotation and Thermal Variation

Describe the general diurnal wind pattern (direction of wind) for near-shore areas

High Velocity Wind at Sunrise

Low Velocity wind at Sunset

What is Albedo

% of light reflected from the surface

Number these from highest (1) to lowest (4) in terms of how much solar energy that reaches the earths surface

actually goes into each.

___ Stored in plants through photosynthesis

___ Heating the air (sensible heat)

___ Evaporating water (latent heat)

___ Radiated back to space as longwave radiation (heat)

_4__ Stored in plants through photosynthesis

_3__ Heating the air (sensible heat)

_1_ Evaporating water (latent heat)

_2__ Radiated back to space as longwave radiation (heat)

If I heat a closed container (so that no air or water molecules can get in or out) containing moist air but no free water,

what happens to the relative humidity of the air in the container, and why?

It decreases

RH=ea/es

es is a function of temperature

Describe the general diurnal wind pattern (direction of wind) for near-shore areas

No wind

What is the main factor that controls the saturation vapor pressure?

Temperature

Wind increases evapotranspiration. How?

It moves the moist air away from the plant.

How does evaporation from snow compare to that from free water at the same temperature?

It is less. Most of the evaporation from snow comes in the form of the snow melting and water evaporating. Evaporation from snow is less then 1/4 of the amount that would come from free water.

Describe how evaporation from a wet soil changes over time

If the soil is saturated evaporation rates are high

As soil dries the amount of free water decreases

lowering the evaporation overall

Name the two places that water goes as part of the photosynthesis process

It becomes a hydrogen source for sugar and some of it leaves during transpiration

How do plants regulate water losses?

Guard cells on their stomates open and close as needed

Once we have a value for the reference ET, what do we do with that to get the actual evapotranspiration for our

specific crop (say, tomatoes) on this day?

Adjust for crop size and stage

What is the most common equation for estimating ET based on climate information.

Penman's Monteith

In words, what are the inputs required to use the most common equation for estimating ET?

Radiation, Wind Speed, Relative Humidity, energy lost to ground

Plants over their lifetime pump more water than their biomass weight. How much more?

____ 2 times

____ 5 times

____ 10 times

____ 100 times

____ > 100 times

100 times

What does the pyranometer measure?

Atmosphere shortwave, Direct sunlight, scattered light, thermal radiation

How is the average daily temperature historically defined, and give an example of a case where this would not be a

very good value.

Average of the max and min

Where it would not be a good fit is on a day where the temperatures stay constant for most of the day and then a storm comes through lowering the temperature for a short time significantly

What are the 2 devices most commonly used to electronically measure temperatures?

Thermistor

Thermocouple

What are the critical factors in operation of a device to measure solar radiation?

Cleaned and Calibrated frequently

What are the 3 general use requirements for a device used to measure air temperature?

Shaded, Ventilated, and at least 30 ft from an extensive radiation reflector and absorber

What does a psychrometer measure, and how does it work?

It uses the wet bulb method to measure relative humidity.

The wet bulb method takes air temperature and wet bulb temperature at 100% relative humidity

I mentioned 3 concerns for cup anemometers. List 2 of those

Sensitive to vertical movement and will not spin at low speeds

For general meteorology, how far from a 100-ft tall tree should you put your wind speed sensor?

400 ft

100*4

Why is it usually specified that an evaporation pan should be placed on a wooden stand?

Heat reduction

How is a weighing lysimeter used to estimate ET?

It allows you to watch water evaporate. It is a weighting bar in a whole plants can grow in this/

How is wind run defined?

Wind distance calculated by speed and time

Velocity * time sum over day

Give an example of how we know that ET and the corresponding precipitation may occur far from each other

Caspian Sea Hot Dry little rainfall on the island

About how much does air temperature change with every 1000ft increase in elevation?

5.5 F decrease

We mentioned 4 ways in which air lifting occurs. Describe 3 of these.

Frontal Pressure differences= pressure differences

Convection Air lifting

Air over mountains warm are moves in and displaces cold air

Why do raindrops rarely exceed 5mm diameter?

Fall apart by drag force

How does expected rainfall intensity change with an increase in the area of interest?

As the area of interest increases the intensity decreases

How does expected rainfall intensity change with an increase in the time period of interest?

As the time period of interest increases the rainfall intensity decrease because you average high and low intensity

Define what is meant by a 2-yr 10-hr storm.

Depth in any 10 hour period that is exceeded once every two years

Which of the following will occur more often?

___ 2-yr 30-minute storm

___ 100-yr 2-hr storm

___ 1-yr 1-minute storm

___ cant tell, given the information provided

1-yr 1-minute storm

Which of the following will have the highest instantaneous rainfall intensity?

___ 2-yr 30-minute storm

___ 100-yr 2-hr storm

___ 1-yr 1-minute storm

___ cant tell, given the information provided

cant tell, given the information provided

When will I be most interested in each of the following:

a) rainfall intensity

b) rainfall depth

A) Runoff and choke point

B) storage

Describe the 3 parts of a good manual raingage

Funnel concentrate rain water, Sharp edge, tall walls to prevent splash out

For a weighing raingage, what are the

a) advantages?

b) disadvantages

a) advantages?

Collects data anytime you want continuous

b) disadvantages

expensive, has to be checked on, evaporation can effect it

For a tipping bucket raingage, what are the

a) advantages?

b) disadvantages

a) advantages?

Very east electronic

Time of tip

Good time resolution

b) disadvantages

poor time resolution at low intensity

Swamping @ High intensity

water is held on top and slowly released not measuring exact time water hits

What must you do to ensure the accuracy of Doppler radar estimates of rainfall?

Must be compared to on the ground data collection

What is the biggest concern with location of a raingage, and how is it addressed?

Wind influence and obstruction

Explain why raingages should generally not be placed on a sideslope

Side slopes can overmeasure or undermeasure precipitation depending on the direction it was coming from

Explain why raingages should generally not be placed on rooftops

the funky winds on top of the roof

Do we generally want raingages placed on a pattern or randomly distributed? Explain why

Where rain is chaotic you want to make sure the gages are placed in a grid pattern

If raingages were placed at the density suggested by the Weather Bureau for general meteorology, how far apart

would the gages be?

600 Km^2/gage

15 mile grid

I will need more raingages to adequately cover a specific area under what 3 conditions?

1) Short Study

2) Small area

3) Convective summer

If I have storm rainfall values at several locations nearby, describe the procedure that I use to estimate what the

rainfall was here?

Theisses Polygon method

Average over area

Perpendicular line sector created polygon

How do I check whether a raingage gives consistent readings over time?

Compare data to near by gages

If I have storm rainfall values at several locations nearby, how do I get an average rainfall depth over the entire area

of interest?

Theisses polygon method

What are the general problems experienced with measuring snow?

Very difficult to use a gage

Wind effects snow

Frozen

Spatial variability

Describe use of a manual or weighing raingage for measuring snowfall

Use Antifreeze or a heated rain gauge to measure snowfall

Describe use of a tipping bucket raingage for measuring snowfall

use a heated topping bucket

Describe use of snow pillows for measuring snowfall

measures the weight of the snow on top of the device

Describe use of a snow survey for measuring snowfall

Measures the depth over space (Spatial variability)

Set a representative transept

Remove snow cutter avoiding soil

small tube holds snow better

larger tube gets better measurement

weigh to get the mass or volume

What is the general range of depths of snow equivalent to 1 of water?

5-12 inches of snow for 1 inch of water