CLOUD

MOUNTAIN VIEW, Calif. -- A U.S. Navy weather center, powered by supercomputers from SGI, is providing U.S. military forces deployed in the Persian Gulf with highly accurate meteorological information critical to conducting land, sea and air operations. Should the United States go to war with Iraq, weather will have a major impact on how U.S. military operations are conducted in the region. "Understanding the environment of the battlespace is critical to the success of U.S. military operations," said Dr. Richard Spinrad, technical director to the oceanographer of the Navy. "Meteorological and oceanographic conditions affect the safety and effectiveness of combat personnel, ships, aircraft and ground vehicles, as well as the performance of sophisticated sensor and weapon systems. Mission planners need accurate and timely environmental characterization to choose the right target, the right weapon, the right delivery system, the most effective tactics and even the best time for the strike. To do this requires a lot of data from remote and on-scene sensors, and a lot of computing power to analyze it." The Fleet Numerical Meteorology and Oceanography Center, Monterey, Calif., is home to three SGI(R) supercomputers: a 512-processor SGI(R) Origin(R) 3800 server, a 128-processor SGI Origin 3800 server, and a 128-processor SGI(R) Origin(R) 2800 server. The combined computing power of these supercomputers has created one of the world's most sophisticated tools for global weather and ocean modeling, which taps into the largest existing real-time databases of oceanic and atmospheric observations. Fleet Numerical operates 24 hours a day, 365 days per year and distributes meteorological information to military users around the world based on sophisticated global and regional meteorological and oceanographic models. For instance, the Navy's Coupled Ocean/Atmosphere Mesoscale Prediction System is used to predict changes in ocean and weather conditions in highly complex coastal areas of the world such as the Persian Gulf. "Every day, U.S. military forces around the world depend on accurate weather forecasts generated by SGI supercomputers at Fleet Numerical to plan and carry out important missions, " said Mike Clancy, chief scientist, Fleet Numerical. "Our weather forecasting models result in about 500,000 daily oceanographic and atmospheric charts, analyses and forecasts, based on data gathered from satellites, ships buoys, and other weather and ocean sensor sources." Weather conditions affect the successful deployment of a broad spectrum of U.S. weapons systems from ships to tanks to fighter planes: -- Temperature: High temperatures reduce aircraft lift capability and decrease the time personnel can remain in armored vehicles. High temperatures cause gun tube droop, shimmering and mirages and can make vehicle exteriors too hot to touch. Extremely high temperatures also increase water consumption by troops. -- Humidity: Coupled with high temperatures, high humidity decreases crew effectiveness in closed armored vehicles. High humidity and temperature affect aircraft lift and significantly reduce a soldier's ability to work and fight. -- Barometric pressure: In armored vehicles, the weight of the air affects gunnery computations and ballistic performance. -- Wind: Strong winds, especially crosswinds, affect aircraft control near the ground during takeoffs and landings. They also affect ground speed for low-level flights. Trajectory projections and first-round hit capabilities for armored vehicles are affected by high crosswinds. In the desert, strong winds produce dust storms that can last for hours or even days. Wind speed and direction are critical to predicting the airborne spread of toxic material from chemical, nuclear or biological weapons. -- Visibility: The lack of good visibility affects landings and takeoffs, visual reconnaissance, target acquisition and designation, terminally guided munitions, and the ability to scatter mines. Poor visibility affects visual acquisition and degrades laser range finding and target acquisition systems. -- Cloud cover: Clouds are always a major consideration for air operations. Low overcast clouds limit the effectiveness of aerial illumination devices. Overcast skies tend to limit heating of inactive targets and lower target detection range for thermal sights. Night vision devices are limited by clouds blocking natural illumination from the moon or the stars. Combat air support and aerial resupply missions are degraded by low clouds. -- Precipitation: Rain can affect visibility and the safety of both flight crews and aircraft. In some instances, precipitation may cause pre-detonation of munitions. -- Aircraft icing: Under certain atmospheric conditions, aircraft structural icing can become a serious, even deadly, problem. It places added weight and drag on the aircraft and can change the aerodynamic shape of the wings, reducing lift and maneuverability. Most dangerous of all, chunks of ice can break off of the airfoil, get sucked into the jet intake and destroy the engine. -- Thunderstorms and lightning: Extreme weather that includes thunderstorms and lightning is very hazardous to in-flight operations, refueling and rearming operations. Severe weather can affect Navy vessels. Small vessels, in particular, are susceptible to bad weather that impairs their ability to transit and/or conduct operations. Wind and wave action-induced background noise and sediment dispersion also negatively impact Navy sensor employment. -- Turbulence: Severe weather and clear air turbulence is a critical condition affecting all aviation assets and missions. It may cause aircraft structural damage or even crashes during takeoffs and landings. Severe turbulence may cancel all operations.