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. Ocean Physics Education, Inc., 2014

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.

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

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

WLG’s measure oceans phenomena in a wide range of space-time scales PhenomenaTime Scale Coastal Seiches6 minutes to 2 hours Tides3 hours to 18 years Meteorological-OceanicHours to Months Long-term trends in Mean Sea Level Years to Centuries PhenomenaSpace Scale Coastal SeichesLess than 50 Kilometers Tides Hundreds or Thousands of Kilometers Meteorological-OceanicLocal to Regional Long-term trends in Mean Sea Level Regional to Global

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= ± 1.3 days, years)  Discovery of Meteotsunamis generated by pressure jumps associated with the arrival of strong tropical waves  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.

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

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)

AUG Tropical Wave

Atmospheric Pressure Jumps

Meteotsunami on AUG detected by the WLG’s array 10 km 25 km 50 km

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

WLG Station Time of MAX Height (LST) Height (feet)Height (cm) Puerto de Fajardo 14: Bahía Salinas16: Puerto Real (C2)16: Puerto de Yabucoa 14: Puerto Real (C1)16: Santa Isabel15: Isla Magueyes13: Puerto de Mayagüez 16:

Meteotsunami Genesis in three steps for Fajardo Harbor

Path length of the Meteotsunami, 51 km

Meteotsunamis are frequent on August Six events between 2011 and 2014

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

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

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 )many others AbtDerechos/derechofacts.htm

June Derecho

Four WLG’s made possible to measure the meteotsunami’s speed June DART buoy Sta , H=2443 m, N 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.

Meteotsunami Height in Deep-Water was 2.1 cm

Meteotsunami: Bermuda and Mona

Meteotsunami speed was 455 MPH

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

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

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

WLG’s Records in Puerto Rico ( ) Magueyes Island 1.81 mm/yr San Juan Harbor 2.19 mm/yr

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