Why Do Some Researchers Use [mm a-1] Instead of [mm yr-1]?

  • Thread starter travroth
  • Start date
  • Tags
    Unit
In summary, the paper discusses a hydrological context in which the mm per yr guess seems quite small, and the unit is referred to as "mm per annum."
  • #1
travroth
5
0
1. I am reviewing a paper and came across a unit that I am having a hard time understanding. Has anyone ever seen the unit [mm a-1] as used for a recesssion rate or trend?

My assumption is that is could be mm per annum but then why wouldn't they just use mm yr-1?

Thanks.

T
 
Physics news on Phys.org
  • #2
What is the context? What you're suggesting makes some sense, but I don't know if it fits the context at all.
 
  • #3
This unit is found in a hydrological context, specifically when expressing the rate of change in aquifer storage, i.e. when a shallow aquifer in a hillslope decline during periods of drought. This makes the mm per yr guess seem quite small considering aquifer water storage levels are fluctuating orders of magnitude more than that each year. Could the unit [a] be a unit of area? that doesn't make much sense to me either though...

Thanks for the interest and response.
 
  • #4
Hmm, that is odd. Let me ask a civil engineering friend of mine. I'll get back to you soon. If you find out what it is, let me know.

My initial inclination is that maybe mm doesn't refer to millimeters. Could be it be a typo for mM (milliMolar)? But I don't immediately see how that would be referenced in this context.

Cheers.
 
  • #5
travroth said:
1. I am reviewing a paper and came across a unit that I am having a hard time understanding. Has anyone ever seen the unit [mm a-1] as used for a recesssion rate or trend?

My assumption is that is could be mm per annum but then why wouldn't they just use mm yr-1?

Thanks.

T


I did a google search on your term, and got a few hits. This paper/book uses the unit, starting on page 21:

http://books.google.com/books?id=hu...=X&oi=book_result&resnum=9&ct=result#PPA21,M1

and this one, starting on page 32:

http://books.google.com/books?id=gB...=X&oi=book_result&resnum=6&ct=result#PPA32,M1

the first one uses the term "isobases" in association with the units, and adding that term to the search, gives this (see page 317):

http://books.google.com/books?id=2KlSteO7tiUC&pg=PA317&dq="[mm+a-1]"++isobase

It sure looks like a "mm per annum" kind of unit, which turns out to be pretty commonly used:

http://www.google.com/search?sourceid=navclient&ie=UTF-8&rlz=1T4GGLL_enUS301US302&q="mm+per+annum"

.
 

Related to Why Do Some Researchers Use [mm a-1] Instead of [mm yr-1]?

1. What is unit clarification?

Unit clarification is the process of defining and specifying the units used in a particular measurement or calculation. It involves identifying the type of unit (e.g. length, mass, time) and the specific unit within that type (e.g. meters, kilograms, seconds).

2. Why is unit clarification important in scientific research?

Unit clarification is crucial in scientific research because it ensures that all measurements and calculations are consistent and accurate. It allows for clear communication and comparison of data between different studies and researchers.

3. How do scientists determine the appropriate units to use in their research?

Scientists typically follow the International System of Units (SI) when determining units for their research. They consider the type of measurement being made and choose the appropriate SI unit (e.g. meter, gram, second). In some cases, scientists may also use specialized units specific to their field of study.

4. Can units be converted between different systems of measurement?

Yes, units can be converted between different systems of measurement using conversion factors. These factors are based on the relationships between the units in each system and allow for accurate conversion between them.

5. What are some common mistakes that can occur with unit clarification?

Some common mistakes that can occur with unit clarification include using the wrong units, not including units in calculations or measurements, and using non-standardized units. These mistakes can result in inaccurate data and hinder the progress of scientific research.

Similar threads

  • Atomic and Condensed Matter
Replies
3
Views
607
  • High Energy, Nuclear, Particle Physics
Replies
18
Views
2K
  • Special and General Relativity
2
Replies
64
Views
3K
Replies
18
Views
1K
  • STEM Career Guidance
Replies
10
Views
1K
Replies
35
Views
5K
  • Engineering and Comp Sci Homework Help
Replies
2
Views
1K
  • STEM Career Guidance
Replies
2
Views
697
Back
Top