Presentation at The IV Caribe EWS Short Course on Sea Level, Station Installation, Maintenance, and Leveling, Quality Control and Data Analysis, University of Puerto Rico, Mayaguez, November 6, 2014.

1. Current Applications for
an Array of Water Level
Gauge Stations
NEW DISCOVERIES IN THE SEICHE BAND AND THE
METEOROLOGICAL-OCEANIC BAND
Edwin Alfonso-Sosa, Ph. D.
Ocean Physics Education, Inc. , 2014

2. A Tide Gauge is a Water Level
Gauge (WLG)
 The term “tide-gauge” is inadequate to
describe or contain all the current
applications of this kind of oceanographic
instrument. A more proper name should be
a Water Level Gauge (WLG), because it
measures changes or oscillations in water
levels due to a myriad of oceanographic and
atmospheric phenomena. Tides are just one
contributor to water level variability.

3. Physical Parameters Measured by
WLG’s
A single station can record:
 Water Level Height
 Amplitude of the oscillation
 Time
 Time scale of the oscillation
 Period or Frequency of oscillation
 Arrival time of a particular
oscillation
 Form
 Linear or nonlinear form
 Symmetric or asymmetric form
 Single or mixed form
An array of stations
allow us to determine
the:
 Coherence between stations
 Age or lag time of any
event.
 Important for warning
systems.
 Spreading or Spatial
Coverage of an event
 Wave Speed or Celerity
 Pinpoint the Source Area of
a particular event

4. Ocean Phenomena and Some
Applications of WLG's
 COASTAL SEICHES
 Meteorological Origin
 Meteotsunami
 Oceanic Origin
 Internal Solitary Waves (Internal
Solitons)
 Seismic Origin
 Tsunamis
 TIDES
 Hydrography
 Prediction of Tidal Heights
 Tidal Datum, Chart Datum
 LONG-TERM TRENDS OF SEA LEVEL
 MSL Trend due to Global Warming
 Vertical Motions of the Earth’s Crust
 METEOROLOGICAL-OCEANIC
EFFECTS
 Changes in Atmospheric Pressure
and Winds
 Storm surge
 Changes in Ocean Circulation
 Geostrophic currents
 Oceanic eddies
 Kelvin waves
 Coastal trapped waves (CTW’s)
 Edge waves
 Climatic Processes
 Thermal Heating

5. WLG’s measure oceans phenomena in a wide
range of space-time scales
Phenomena Time Scale
Coastal Seiches 6 minutes to 2 hours
Tides 3 hours to 18 years
Meteorological-Oceanic Hours to Months
Long-term trends in Mean Sea
Level
Years to Centuries
Phenomena Space Scale
Coastal Seiches Less than 50 Kilometers
Tides
Hundreds or Thousands of Kilometers
Meteorological-Oceanic Local to Regional
Long-term trends in Mean Sea Level Regional to Global

6. An Array of WLG’s is a Sensitive Instrument
Capable of New Discoveries
Let’s see some recent discoveries made possible by the WLG’s array.
 In the Seiche Band
 2011-Discovery of the Magueyes Cycle of extreme seiche activity
(T= 6202.2 ± 1.3 days, 16.98 years)
 2011-Discovery of Meteotsunamis generated by pressure jumps
associated with the arrival of strong tropical waves
 2013-First measurements of a Transatlantic Meteotsunami
 In the Meteorological-Oceanic Band
 2011-Discovery of Edge Waves trapped on the Cabo Rojo-Mayaguez
Shelf, about 30 hours after the passage of Hurricane Irene over
Puerto Rico
 In the Long-Term Band
 2012-Two stations confirm a positive trend of Sea Level Rise around
Puerto Rico.

7. Locally Generated
Meteotsunamis
DISCOVERED BY MEANS OF THE WLG’S ARRAY

8. Meteotsunami
 The term Meteotsunami is used to designate a series of waves in a
harbor (bay) that show a similar frequency or amplitude to that of
a tsunami generated by earthquakes, landslides or volcanic
eruption but unlike these, its origin is associated with an
atmospheric disturbance able to generate a barotropic long wave
in the open sea, resonate with it (Proudman resonance) as
approaches the coast. Once reaches the harbor (bay) is capable of
forcing a number of waves, which enter in a second resonance
with the harbor (bay) which amplifies it again. The meteotsunami
only occurs in certain harbors (bays) where this double resonance
is possible.
 Atmospheric disturbances
 a jump in atmospheric pressure
 atmospheric gravity waves
 the passage of a front
 a line of strong winds (squall)

9. AUG-16-2011 Tropical Wave

10. Atmospheric Pressure Jumps

11. Meteotsunami on AUG-16-2011
detected by the WLG’s array
10 km
25 km
50 km

12. Meteotsunami detected by a WLG at
Puerto Real, Cabo Rojo
Units are feet

13. WLG Station
Time of MAX
Height (LST)
Height (feet) Height (cm)
Puerto de Fajardo 14:30 0.61 18.6
Bahía Salinas 16:30 0.61 18.6
Puerto Real (C2) 16:30 0.48 14.6
Puerto de Yabucoa 14:12 0.44 13.4
Puerto Real (C1) 16:30 0.42 12.7
Santa Isabel 15:00 0.35 10.7
Isla Magueyes 13:48 0.30 9.0
Puerto de
Mayagüez
16:24 0.22 6.7

14. Meteotsunami Genesis in three steps
for Fajardo Harbor

15. Path length of the
Meteotsunami, 51 km

16. Meteotsunamis are frequent
on August
Six events between 2011 and 2014

17. Meteotsunamis are easier to detect in wider
platforms and narrow harbors
Water Level Record Detided Signal

18. Speed of a Transatlantic
Meteotsunami
DISCOVERED BY MEANS OF THE WLG’S ARRAY

19. Some Derechos can
generate Meteotsunamis
 A derecho is a widespread, long-lived wind storm. Derechos are
associated with bands of rapidly moving showers or thunderstorms
variously known as bow echoes, squall lines, Wind damage extends for
more than 240 miles (about 400 kilometers), includes wind gusts of at
least 58 mph (93 km/h) along most of its length, and several, well-
separated 75 mph (121 km/h) or greater gusts.
Extracted from the web site:
ABOUT DERECHOS
Part of the NOAA-NWS-NCEP
Storm Prediction Center web site
Prepared by Stephen F. Corfidi,
Jeffry S. Evans, and Robert H.
Johns (with the help of many
others)
http://www.spc.noaa.gov/misc/AbtD
erechos/derechofacts.htm

20. June 13 2013 Derecho
http://cimss.ssec.wisc.edu/goes/blog/wp-content/uploads/2013/06/SPC_low_end_derecho.png

21. Four WLG’s made possible to measure the
meteotsunami’s speed
June 13 2013
DART buoy Sta. 44402, H=2443 m, 39.399 N
70.942 W, located 186 miles east of Atlantic
City, NJ. Travelled 1478 miles in 3.25 h.
Detected by WLG’s located
at: Arecibo, Punta Cana and
Mona Island.

22. Meteotsunami Height in Deep-
Water was 2.1 cm

23. Meteotsunami: Bermuda and
Mona

24. Meteotsunami speed was 455
MPH

25. Three Previous Transatlantic
Meteotsunamis in Mona Island
Average Speed is 427 MPH

26. Do larger meteotsunamis
show faster speeds? We
need more data.

27. Mean Sea Level trend in
Puerto Rico
DISCOVERED BY MEANS OF THE WLG’S ARRAY

28. WLG’s Records in Puerto Rico (1955-
2012)
Magueyes Island 1.81
mm/yr
San Juan Harbor 2.19
mm/yr

29. Acknowledgements
We acknowledge the use of WLG’s Data and Ocean Buoy
Data provided by the following:
 CariCOOS
 IOC
 CIMSS - University of Wisconsin-Madison
 NOAA / NOS / CO-OPS
 NOAA / NDBC / DART Program
 NOAA / NWS