Friday, March 13, 2015

Once in a Lifetime PI Day Saturday

Saturday is PI day.  It's a very special PI day because it corresponds to the exact date:


If you continue the date to include the hour, minutes and seconds, it would read:

3-14-15  9:26:53

Check out the commemorative PI t-shirt.  

This is all great but why is PI so important?  Its a day to teach kids math by making it fun. Your kids might have PI day activities planned at school today (Friday).

I'm sure back in 1737 when Leonard Euler first used the symbol π, he never envisioned the fascination with π that developed since.  There are t-shirts, π plates (yes, I have two), π mugs...and on and on. Novelty websites have just about every π trinket you can think of!

What is PI " π"?

PI is the number that represents the ration of a circle's circumference to its diameter.

The Interesting part is that PI is a non-repeating, never ending decimal so its very nature is an approximation. Mathematicians have tried to find a patterns that might define π since ancient times. Archaeologists believe that the ancient Egyptians constructed the Great Pyramid of Giza with knowledge of π. Greek mathematician Archimedes was the first to calculate a range for π using polygons.

Throughout its history, π has become a fascination among mathematicians and computer programmers. Welsh mathematician William Jones was the first to use the symbol π to represent the ratio of a circle's circumference to its diamater in the early 1700s. In the 1940s, a little over 1000 digits of π were known.

As we entered the computer age, the calculation for more digits became a test for computer system efficiency and accuracy. In 2014, scientist Ed Karrel calculated more than 10 QUADRILLION decimals of PI.  Here is his blog.

To put the number of digits in Ed Karrel's calculation into perspective, you only need 39 digits of PI to calculate the circumference of the observable universe (assuming it's a sphere) to the accuracy of a width of the inside of an atom!

To put it another way, if you were to recite EVERY digit, it would take you 317,000,000 years to complete. You'd need to start before the dinosaurs were alive in order to finish today!

All of this great if you are a math or computer geek. But why should the rest of us care?

PI is present in every aspect of our lives. PI is used in most calculation in the development of all the world's infrastructure. All communications, CAT scans, MRI machines, genetic research, propulsion systems (space and military aircraft), quantum physics....the list goes on.

Famous scientific discoveries and the math that describes them incorporate PI: 

* The calculation for determining the horsepower of your car has PI in it.

* Einstein's famous equations that describe relativity which is now directly applied in   
   satellite calibration has PI in it. Here it is in very simple form: 

* The math that determines electric force (electricity) includes PI.

*  How about the speed and volume of blood flow inside the first artificial heart? You bet.   
    PI is included in that calculation too.

* Want to figure out the position of two planets nearest to the earth? You need PI.

* Radio communications, cellphones, GPS satellites (see Einstein's equation above) computer hard drive/processor technology were both developed using mathematics that incorporates the number "PI".

* Airlines use PI to calculate flying distance around the earth

* Manufacturing uses PI to figure out how much of a substance will fit into a volume 
   of circular or cylindrical space

You might not like math. You might not get PI.  Just remember that PI (3.14159...) is integrated into our everyday life unlike any other number. Without it, your daily life would be totally different.

Monday, March 09, 2015

End of Winter Right? Not So Fast

Northern Ohio has not had a string of days above 40 degrees similar to what we will enjoy this week since the week of Christmas. That stretch went from December 22nd to December 28th (44, 52, 59, 41, 49, 54 and 47).  While it feels great as it melts off the majority of the snow cover (big piles will stay around a while), the pattern is still ripe for more cool air relative to the averages for this time of year.

To be clear, mid March sun is much stronger than mid January sun.  The average temperature for March 8th is 44 degrees. The average temperature on March 23rd is 50.  So temperatures in the 30s or lower 40s would be considered below average. It's all relative to the season in question. It's not arctic but its not considered spring.

One of the components that we use in formulating longer range outlooks of 8-14 days is the EPO.  Its a measure of the pressure patterns in the eastern Pacific Ocean (EPO region in red boxes---excuse my crude drawing). I also included the WPO which is another favor in evaluating the pressure pattern (further west) over the Pacific Ocean.

This winter (since January), high pressure has settled over Alaska and western Canada/western US while low pressure developed south northern of Hawaii. Notice the trough and cold across the eastern US.  When the EPO is negative, this favors cold and snow east; milder temps and dry west.

The EPO has bounced back positive recently.  The trough in the east and the cold have retreated north as the ridge slid east.

By the 3rd week of March, it will more than likely drop negative again which will strongly favor colder than normal temps in the east again.


Notice how the temperatures spike later this week (dates are on the bottom) then drop below normal starting mid week next week on the graph below. See how temperatures fall but only into the 30s.

The bottom line:  Below normal temperatures around the 20th of March means temperatures below 50 degrees.  So highs in the 30s up through the mid 40s would classify. Not arctic cold but NOT SPRING...yet.

Monday, March 02, 2015

Where Does This Winter Cold/Snow Rank All-time in Cleveland?

Frozen Tundra covering Lake Erie

The meteorological months of winter are December, January and February. The snow cover across northern Ohio is very deep after the recent snowfall. This endless blanket of the white stuff makes this definition seem, at the very least, misleading and pretty pointless to many of us who still have snow piled up high. When we do meteorological comparisons to past seasons, the three month periods nearest to the season in question is used by climatologists. For example, December through February are the winter months. March through May are spring months and so on.

So how does this winter compare to last winter (colder than average), two winters ago (milder than average) and the coldest winter ever (1976-77) in northern Ohio?  I'll use the same metrics for comparison I've used in the past:   

Average 3 month temperature rank all-time (December through February) since 1871
Seasonal Snowfall
Below zero nights
Days at or above 40
Days at or below 32
Consecutive days with at least one inch of snow cover
Total days with snow cover of at least one inch
Total days with snow cover of at least six inches

Monthly temperature ranks



Add caption

* The only winters that were colder in the last 50 years were:  1976-77, 1977-78 and 1969-70

*  The average temperature from January 1 to February 28th was the 6th coldest EVER, coldest since 1977-78, 4th coldest in the last 100 years, 3rd coldest in the last 50 years

2) Seasonal Snowfall


*  This winter's snowfall rank is 14th. Last winter was 9th, Two winters ago was 59th

3) Below Zero Instances

SIDE NOTE:  Only 4 other winters had more temperatures below zero since record keeping began in Cleveland:  1978-79 (14), 1962-63 (16), 1884-85 (19) and 1976-77 (24)

4) Daytime high temperatures at or above 40 degrees

5) Daytime high temperatures at or below 32 degrees

6) Consecutive days with at least one inch of snow cover

 SIDE NOTE: Current stretch now at 40 days as of March 2nd

7)  Total days with snow cover of at least one inch

 SIDE NOTE:  This winter's number of snow cover days is ranked 10th all-time. Last winter was ranked 8th all-time. 

8) Total days with snow cover of at least six inches

9) Monthly temperature ranks since November

Feel free to comment below; any questions always welcome!