lightning by cuiliqing

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```									Lightning in Salt Lake
and Utah Valleys

Michael Olson
Meteo 5120
Applied Math and Statistics
John Horel
Purpose
●   To determine where lightning has more
potential to strike
–   Over water
–   Over land
–   Over mountain
●   Increase understanding of lightning “danger
zones.”
●   Increase understanding of when lightning is a
possibility – increase forecasting ability.
Prior Research
●   “Where Lightning Strikes,” an article from NASA's magazine
Science at NASA, Dec. 5, 2001, Internet posting:
–   Research on locations where lightning occurs more
frequently. Lightning avoids the oceans and the poles,
but is attracted to land.
–   The mapping of lightning activity is done by satellite.
●   “A Bolt out of the Blue” from Scientific American, May 2005
issue.
–   Experiments done in Florida relating lightning and X-
rays. Florida chosen because lightning occurs very
frequently there without notice, or “Out of the Blue.”
●   Other research done that doesn't apply to results.
Null Hypothesis
●   Due to the higher conductivity of the salty air
around the Great Salt Lake, a potential for a
lightning strike is greater.
●   Due to the lower pressure and dryer air of the
higher altitudes, lightning strikes are more
rare in the mountains.
Procedure
●   Obtain and clean data so it is readable into
Matlab
●   From data set, select only the strikes in the
Salt Lake and Utah Valleys (40° N to 41°45'
N and 111°30' W to 113°15' W)
●   Separate data into regions of land, water, or
mountain
●   Produce Plots
Procedure (cont...)
●   Calculate area (in Degrees2).
●   Find Strike Density (# of strikes per unit
area). Yields units of Strikes/Degree2.
●   Calculate probabilities of a lightning strike in
each of the three regions.
Data
Raw Data
STN YYMMDD/HHMM              SLAT    SLON      SGNL     MULT

+     050601/2100                23.96    -79.65    190.00    1.00

-    050601/2100                 27.26    -87.50    -130.00   1.00

-    050601/2100                 43.96    -117.32   -30.00    1.00

-    050601/2100                 27.96    -85.16    -150.00   8.00

Pipe through datafix.c
0506012100     23.96 -79.65 190.00    1.00

0506012100     27.26 -87.50 -130.00   1.00

0506012100     43.96 -117.32 -30.00   1.00

0506012100     27.96 -85.16 -150.00   8.00
2004

Strikes on Land

Strikes on Water

Strikes in Mountains

June   July   August

2005
Month         Lake Density       Land Density      Mountain Density   Lake Strikes        Land Strikes        Mountain Strikes Total Strikes
June 2004                370.07             815.82           1095.5                 181                1029                  876              2086
July 2004                478.43             202.97           217.61                 234                 256                  174               664
June 2005                1069.3             1291.5           1609.6                 523                1629                 1287              3439
July 2005                  132.9            402.76           514.01                  65                 508                  411               984
August 2005              519.32             1400.9           2007.3                 254                1767                 1605              3626
Summer 2004                848.5            1018.8           1313.2                 415                1285                 1050              2750
Per month              424.25              509.4            656.6               207.5               642.5                  525              1375
Summer 2005              1721.5             3095.2           4130.8                 842                3904                 3303              8049
Per month              573.83           1031.73           1376.93              280.67             1301.33                 1101              2683
2004 – 2005                 2570              4114             5444                1257                5189                 4353             10799
Per month                  514             822.8           1088.8              251.74              1037.8                870.6            2159.8

Highest Densities                        Areas (Deg2)              0.4891              1.2613              0.7996            2.5500
Lowest Densities
Possible Causes of Error
●   Inaccurate estimations of
land/water/mountain locations
●   Not enough data
●   Use of latitude & longitude for area instead of
Cartesian coordinates.
Ways to minimize error
or obtain clearer results
●   More data
●   Compare month to month series analysis
(compare all Junes to each other, all Julys to
each other, etc.)
●   Compare with other bodies of water (salt
water vs. fresh water, large body vs. small
body, etc.)
●   Better area units (km2 instead of Degrees2)
Summary of Results &
Conclusion
●   Average probability of lightning
–   Over water:       251.4 / 2159.8 = 11.6%
–   Over land:        1037.8 / 2159.8 = 48.1%
–   Over mountain:    870.6 / 2159.8 = 40.3%
●   Water is not more conducive to lightning, even if the air
above contains conductive ions like Na+ and Cl-.
●   The possibility of a lightning strike is highest over land
using probabilities, but highest over mountain ranges
using strike densities.
Future Research
●   Why is July so sparsely populated with
lightning strikes?
●   What are the conditions that enhance the
probability of lightning?
●   What makes some area of the world (such as
Florida) ideal for lightning strikes and others
not (like the Pacific Islands)?

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