In This Issue In the August 2011 edition of GeoView, we are proud to unveil a video introduction to VectorLock, the first security system for shapefiles. We also feature a detailed look at the Q3 US Parcel layer update as well as details on a new pricing model for pipelines and other corridors. From our partners, we have a new DigitalGlobe aerial coverage map for the US and Europe and details on the second edition of SPOTMAPS Australia.
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The Area of Interest Niagara Falls Considered one of the seven forgotten wonders of the world, Niagara Falls is a breathtaking tourist destination. Located on the Niagara River, it acts as an international water barrier separating the United States from Canada. It is composed of two major sections, the Horseshoe Falls on the Canadian side, and the American Falls on the U.S. side. These two sections are separated by Goat Island, a popular destination on the American side accessible by foot, car or trackless train. It derives its name from a herd of goats that was kept on the island in the late 1700s, but due to an extremely harsh winter, only one goat survived. Also included in Niagara Falls is another smaller waterfall called Bridal Veil Falls. At its base is the Cave of the Winds which provides a protective barrier from the runoff - and is a very kitschy place for people to get married – hence its name. The name Niagara is believed to be derived from “Niagagarega” who were a local branch of the Iroquois Nation that resided in the area when French settlers arrived in the 1700s.
On June 10th of this year, NASA, partnering with Argentina’s Comisión Nacional deActividades Espaciales (CONAE), launched the Aquarius instrument into orbit at 657 kilometers above Earth’s surface.
Launch of the Aquarius instrument on the SAC-D launch vehicle.
The Aquarius instrument is aptly named as its principle goal is to map the surface of the Earth’s oceans. The satellite is capable of mapping the entire Earth’s sea surface salinity once every seven days. This will allow researchers to compare the seas’ salinity on a monthly, seasonal and yearly basis.
The salinity of seawater determines its buoyancy and density; these in turn affect ocean dynamics, stratification and water mass mixing and formation. The ocean’s salinity also has an impact on how freshwater moves through the water cycle. Mapping sea surface salinity will give researchers a better understanding of the Earth’s water cycle and how climatic variations change global ocean circulation, such as El Niño and La Niña patterns.
The long term goal for the satellite is to produce monthly sea salt salinity maps at 150-kilometer resolution for the 3-year lifespan of the mission.
Technicians working on the Aquarius instrument. (Source: NASA)
Aquarius measures sea surface salinity with the Passive Salinity Sensor L-Band Radiometer. The three 1.413-GHz radiometers have a 390-kilometer swath and varying resolutions. There is also an on-board radar scatterometer that is used to reduce the backscatter and interference from waves that distort sea surface salinity measurements.
Onboard Aquarius are additional instruments provided by CONAE and also the Italian and French Space Agencies. These additional instruments include a Microwave Radiometer (MWR), New IR Sensor Technology (NIRST), High Sensitivity Camera (HSC), Data Collection System (DCS), Radio Occultation Sounder for Atmosphere (ROSA) and CARMIEN 1. These instruments measure a number of environmental factors, including: water vapor, sea ice concentration, precipitation, wind speed, sea surface temperature, fires, urban lights, atmospheric temperature and humidity.
The salinity data is compiled into a map that details its concentration across the entire planet. When all of the data collected by the various instruments is combined, it will allow researchers to create more accurate sea surface salinity maps and incorporate them into climate change models.
The resolution of present day instruments (top-most map) compared to the resolution of the Aquarius instrument (lower-most map). (Source: NASA)