Alternative Energy Draft EA - NASA Visitor Center at Wallops Flight ...

Wind
Affected Environment
For Wallops Island, prevailing winds in the fall and winter tend to be from the northwest, but
stormy nor’easters can occur. These 2- to 3-day storms produce severe conditions offshore, with
high winds, cold rain, and steep seas due to the open distance of water over which wind can blow
from the northeast. Prevailing winds in the summer are southerly, increasing in mid-morning to
typically lower than 37 kilometers per hour (kph) (20 knots) and usually dying down at dusk.
Offshore fog is uncommon, but can be produced during the spring when a warm, moist,
southerly flow of air passes over the cold ocean water.
Wind speeds are the strongest during the fall and winter months, with winds exceeding 55 kph
(30 knots) more than 5 percent of the time from November through February. Wind speeds peak
in December, when winds exceed 55 kph (30 knots) more than 6 percent of the time. During
these months, the predominant wind direction is from the northwest. During March and April,
winds are more southerly but still strong. March winds exceed 55 kph (30 knots) nearly 5 percent
of the time.
3.1.6 Radar
Radar systems provide space position and/or target characteristic information for a variety of
applications, including surveillance, tracking, weather observation, and scientific remote sensing.
The radar functions are performed by a variety of ground-based and airborne systems in support
of the Wallops Research Range and Earth Science programs. Three surveillance radars and up to
seven (three fixed and four mobile) tracking radars provide data for range safety and mission
requirements. These systems are located on the Main Base, Wallops Mainland, and Wallops
Island. The targets that are tracked include aircraft, balloons, drones, expendable launch vehicles,
reusable launch vehicles, satellites, and sounding rockets.
Radar is used to monitor the altitudes that are used for air traffic to prevent airplane collisions.
All the objects that are illuminated in the radar field reflect some energy back to the radar. The
energy is modified by the reflection process, but radar can use these modifications to
differentiate between different types of objects. The motion of wind turbine blades has a similar
velocity band as aircraft, so if the blades are visible to the radar then they cannot be distinguished
from a moving aircraft. This could cause aircraft near wind turbines to be identified in the wrong
position or be lost in the vicinity of the wind turbine(s). As wind turbine technology changes,
modifications to radar or turbines and blades are being explored (BWEA, 2008).
3.1.7 Noise
The EPA’s Noise Control Act of 1972 (42 U.S.C. 4901 to 4918) as amended by the Quiet
Communities Act of 1978, states that the policy of the United States is to promote an
environment for all Americans free from noise that jeopardizes their health or welfare.
3.1.7.1 Noise Standards and Criteria
Noise is defined as any loud or undesirable sound. The standard measurement unit of noise is the
decibel (dB), generally weighted to the A-scale (dBA), corresponding to the range of human
hearing (Table 10). Since sounds in the outdoor environment are usually not continuous, a
common unit of measurement is the Leq, which is the time-averaged sound energy level. The L 10
is the sound level exceeded 10 percent of the time and is typically used to represent peak noise
46