Two historic storms that devastated the New York/Long Island area were re-created first through data, then through sound. The resulting turbulent and evocative compositions allowed listeners to experience geographically scaled events on a human scale and gain a deeper understanding of some of the more unpredictable complex rhythms and melodies of nature.

Collaborators:
Andrea Polli, Lead Artist, Associate Professor Film and Media, Hunter College NY
Dr. Glenn Van Knowe, Lead Scientist, Senior Research Scientist, MESO, NY
Dr. Kenneth T. Waight, MESO, NY

Engine 27 Programming by Matthew Ostrowski

Engine 27
173 Franklin Street
New York, NY 10013

Click here to view an interactive Shockwave 3D model of the Engine 27 speaker configuration. (best viewed in Internet Explorer with Shockwave plug-in)

The Storms:
(1) Presidents Day Snowstorm Feb 18-19 1979
(2) Hurricane Bob Aug 18-19 1991

These two storms were selected for sonification because one is a strong midlatitude cyclone (Presidents Day Snowstorm) and the other is a strong Hurricane (Bob) that passed though the same coastal region. The sonifications of these two strong storms (that have a very different physical structure) yield insight into the nature of these two different types of storms.

Scale: An area of approximately 1000km has been mapped to the size and shape of the Engine 27 space. Each speaker is mapped to a specific point in space proportional to the area spanning from Northern Florida to Northern New York State and from the Eastern tip of Massachusetts, to Western New Jersey with New York City situated in the center. The model grid resolution is 10km.

A complete model of each storm has been created at 5 points of elevation: sea level, approximately 8500 feet, approximately 18,000 feet, approximately 35,000 feet, and approximately 60,000 feet (or, the top of the atmosphere), and each day’s storm activity is performed in full at each elevation. Each speaker performs a composition using data produced approximately every three minutes over a 24-hour period of the greatest storm activity.

Sonic Mapping: There are 9 variables in the model that are mapped to sound. Temperature, pressure, wind, and moisture are mapped to pitch, timbre, and amplitude of sound. An additional sound composition has been created using only wind speed values in various directions at all elevations.

Temporal Scale: Each speaker performed a composition using data produced every five minutes at a sounding (a specific point in space) over an approximately 48 hour period of storm activity

Storm Details:

President's Day Snowstorm (February 18-20, 1991)
The "President's Day Snowstorm" initially formed as a weak wave of surface low pressure on a front in the Gulf of Mexico on 18 February 2002. It quickly moved northeast. By evening on the 18^th , it was rapidly intensifying off of the Florida-Georgia coast. Then for the next 24 hours it moved north-northeastward paralleling the coast to just south of Long Island where it moved nearly due east.

Exceptionally heavy snow developed from Richmond to New York City. High winds and blizzard conditions also accompanied the heavy snow. The mid-Atlantic states were hit very hard with 1 - 2 feet of snow falling in the areas from Delaware to southern New Jersey.

For more information on The President's Day storm go to:
this link

Hurricane Bob (August 17-19, 1991)
Hurricane Bob developed as a tropical depression in the central Bahamas on August 16, then steadily intensified while drifting north-northwestward. It reached hurricane status on the evening of August 17 off of the mid-Florida Coast. Bob continued to strengthen and move northward passing near Cape Hatteras midday on August 18. During the next 48 hours Bob continued to strengthen and became a category 2 hurricane as it accelerated north northeastward, paralleling the East Coast. The eye of Hurricane Bob passed over Block Island, Rhode Island at approximately 1:30 PM on August 19, and made landfall over Newport, Rhode Island shortly before 2 PM.

The impact of hurricane Bob was felt through the Northeast coastal areas. The most significantly impacted were the immediate coastal communities of Rhode Island and southeastern Massachusetts as Bob brought sustained hurricane force winds of between 75 and 100 mph to this entire region. Peak wind gusts were reported as high as 130 mph. The remainder of the region experienced sustained tropical storm force winds between 50-74 mph, with many areas east of the Connecticut River receiving gusts that reached hurricane force. In addition to the strong "straight line" winds, four tornadoes were reported as Bob came on shore.

For more information on Hurricane Bob go to:
http://www.capecodonline.com/special/hurricane/hurrlinks.htm

General Information About Storms:
There are two basic types of large-scale (called synoptic scale in meteorological jargon) cyclonic circulations or "storms" that effect the northeastern coastal regions of the United States.

(1) Midlatitude Extratropical Cyclones
(2) Tropical Cyclones (Tropical Storms and Hurricanes)

The midlatitude extratropical cyclone is by far the most common type of storm that effects the midlatitude weather. This type of storm involves a large atmospheric counterclockwise (cyclonic) circulation around low-pressure systems. The low-pressure system forms on a front between cold polar and warm tropical air masses. This type of storm can be up to 1200 miles (2000 kilometers) in diameter. The most intense of these types of systems are winter season storms referred to as "Nor'easters".

For more information on midlatitude cyclones and Nor'easters go to:
http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/cyc/home.rxml
http://www.ocean-beach.com/weather_noreaster.htm

Tropical cyclones are storms resulting from cyclonic wind flow around low-pressure systems that form in the tropics and typically occur during the late summer or early fall. There are distinct phases of tropical cyclones based upon the intensity of the wind. The tropical cyclone starts as tropical depression, which if conditions are right intensifies to a tropical storm and then finally hurricane. On occasion these storms effect the Northeast U.S. coastal region.

For more information on tropical cyclones and hurricanes go to:
http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/hurr/home.rxml Even though both midlatitude cyclones and hurricanes are storms resulting from organized low-pressure systems, their structures are very different. For example, the tropical cyclone is very symmetrical when viewed from a satellite and has a vertical structure that is nearly straight up and down. The hurricane winds are strongest in the lower half of the storm; the circulation tends to weaken with height. The midlatitude cyclone is a storm that is very asymmetrical when viewed from a satellite and has the appearance of a "coma". It has a tilted structure in the vertical and its circulation tends to intensify with height.

Atmospherics/Weather Works Multi-Channel Spatial Installation

An example of a one-dimensional 'sounding' showing how values are generated for various elevations (26 possible levels)

General modeling area, low and high resolution

The geographic scale of a storm's path applied to the Engine 27 space.

Satellite image of the 1979 President's Day Storm showing its unusual 'eye feature'

Comparison of Tropical Cyclone with Midlatitude Cyclone

Tropical Cyclone

Midlatitude cyclone

Thermal Structure

Warm Core

Located in the thermal gradient of a front. Part warm cold and part cold core.

Vertical Structure

Vertical, wind speed weakens with height

Tilted, wind speeds that increase in intensity with height.

Energy Source

Latent Heat Release

Temperature Advection of strong Thermal Contrast

Exhaust Mechanism

Outflow (divergence) due to an upper level anticyclone

Divergence due to an upper level jet and trough.

Size

200-300 miles across

Can reach 1000 miles across

Shape

Symmetrical with often clearly defined center (eye)

Irregular Shape. Sometimes hard to find center

Duration

Pass a location usually in 6-8 hrs.

Can effect a region for several days.

Intensity

Tends to be more intense over a smaller region. 74 knots and higher

Lower wind speeds but over a much larger area.

Time of year

June to November

October through April

Geography

Typically forms south of 30 N

Typically forms north of 30 N.