SUMMARY

In our summary of the tutorial, we ask you to respond to questions related to each of the seven topics discussed. You are not being graded on your responses. The intent is to give you an opportunity to review the important points of the lesson, contemplate the information you have hopefully learned, and apply the concepts in real-world situations. The correct responses to some of the questions may include multiple choices.

Adherence to standards: Adherence to standards is important because it:

Answer 1 correct Helps create a level the playing field for the measurement and resulting comparability of data and increases data quality.
Answer 2 is not correct Increases unrepresentativeness of data.
Answer 3 is not correct Guarantees the collection of accurate data.

Metadata: Select the responses you believe should be entered into station metadata.

Correct answer 1 temperature sensor replaced with another of same manufacturer's equipment
Correct answer 2 temperature sensor replaced with different manufacturer's unit
Correct answer 3 removed tree limb overhanging precipitation gauge
Correct answer 4 observer began using snow measurement board for first time
Correct answer 5 changes in land use occurring within 200 feet of station
Correct answer 6 observer changed snowfall measurement frequency from once daily to 4 times a day

REMEMBER: Document any event that you believe may enter a discontinuity into the climate record. This includes changes in the way measurements are made and recorded, and changes in the local physical environment. Err on the side of over-documentation. Coordinate with our climate services partners on issues.

Instrumentation

Select the responses below that you believe are TRUE regarding published climate stations:

Answer 1 is False In the interest of having some climate data versus no climate data, we should install any available equipment we can find.
Answer 2 is False Installation of unapproved instrumentation is acceptable as long as its kept secret and out of the metadata so NCDC and other data users don't know about it.
Answer 3 is TRUE Data continuity and related minimal instrumentation changes is of special consideration at Historical Climate Network (HCN) stations.
Answer 4 is FALSE Off-the-shelf unapproved instrumentation can be assumed to be as accurate and reliable as the manufacturer's advertised capabilities.

Station and Instrument Exposure

This factor is one of the most important as it can contribute a great deal of uncertainty to the climate record and we can exert considerable influence to minimize the impacts. Look at the picture below and select the responses that you believe best fit the situation:

This temperature sensor is situated in a spot that will likely provide high quality readings representative of the surrounding environment.
The equipment is situated fine as it was put it here or nowhere.
I know being close to buildings can reduce the diurnal temperature range and that heat exchangers can artificially affect the readings but who cares? A couple of degrees error doesn't really hurt anything.
The instrument is grossly non-standard in exposure and should be relocated farther away from the building and air exchanger or closed down.

REMEMBER: Also, understand and respect the fact that topographic setting can be much more important in determining whether a relocated station keeps the same name (has climate continuity with the previous site) or gets a new name (begins a new climate record) than the 5 horizontal mile/100 vertical feet rule. And when in doubt or just needing input on exposure issues, coordinate with our climate community partners.

Changing Environments

Changing environments are a fact of life that are difficult to totally avoid. In many cases, the best we can do is fully document any conditions in the local vicinity of the station which can introduce discontinuities into the climate record. This is best accomplished through keeping accurate and complete metadata.

When non-compliant situations are extreme, either correct the situation or consider closing the station down. Take digital photographs with each scheduled preventative maintenance visit per guidelines or as needed when change is apparent. And of course, don't forget to coordinate issues with our climate community partners. They are ready and willing to assist with their climate expertise.

Observing Practices

Although the method in which we take environmental measurements may change over time to reflect changes in technology and needs, these changes, if not documented can seriously affect the accurate interpretation of data and derived products.

Snowfall measurements provide an excellent example. Consider an observer who, during a snowstorm, places 3 snow measurement boards side-by-side in his backyard. On board A, she takes a measurement of how much snow fell each hour, followed by sweeping the surface clean for the next measurement. On board B, she follows the same procedure , but measures the snowfall depth every six hours. On board C, the same as boards A and B but takes the measurement only once in 24 hours before cleaning the board.

Which snowfall measurement is the correct value to report? Without measurement frequency standards, even though each procedure and board results in a different amount, all three would be valid. However, since we do have a standard, which allows for up to four measurements no closer than 6 hours apart or optionally, once per 24-hours, either boards B or C are correct.

The morale of the story is that for comparability's sake, and continuity in time and between stations, we must all adhere to standards of measurement to assure the highest quality data possible. And when the methodology changes, the date and procedural changes must be documented in the metadata if data users are to be able to accurately assess climate trends and variability.