THE GULF WAR : DEPENDING ON THE WEATHER

It’s winter in the Mideast desert, and clouds and fog are having an impact on the war. In this region, the rainy season lasts from November to March. The inclement weather isn’t necessarily grounding all planes, but it is affecting the selection of targets, the ability to make damage assessments and perhaps the volume of attacks. Some of the areas in which weather makes a difference: SATELLITES AND RADAR: -- Satellites function best in clear skies. In general, those that use radar would be less affected than those that use visual light. But for the latter, clouds could obscure the ground. -- The Lacrosse radar-imaging satellite--at its 495-mile-high altitude--can reproduce data in all weather. Using powerful radar, it is thought that it can penetrate cloud cover and perhaps the first few feet of the ground. -- Advanced KH-11 or Keyhole satellites use infrared instruments to detect heat. In better weather, the Keyhole photo reconnaissance satellites can do even more. Under bright sun, for example, with a satellite directly overhead, there is resolution down to a few inches. It can see a license plate, although not read it. Extended Forecast: The clouds currently plaguing allied air surveillance operations are an annual weather feature of the Persian Gulf winter season. Low-pressure areas, bringing clouds and occasional showers, travel over the Black Sea and across the Turkey-Iraq area. Observers say this will be a frequent weather pattern over the next several weeks. Regional Forecast: Iraq: Blowing dust, sand along borders with Saudi Arabia and Kuwait today. Mostly cloudy skies, chance of showers in the extreme north. Patchy fog over central and eastern Iraq Wednesday. Baghdad, mostly cloudy 41/61. Saudi Arabia: Cloudy skies and chance of showers near the gulf, mostly cloudy skies over the central region. Patchy fog in some regions Wednesday. Riyadh, partly cloudy 45/71 PLANES -- Even in bad weather, sophisticated technology allows pilots to fight at night and fire laser-guided projectiles. But those systems on planes such as the F-15E, F-16, F-111, F-117 are affected by cloud cover. Soot or smoke--perhaps from a refinery fire--would also affect them. -- Laser beams, used in advanced navigational systems, are greatly diffused by clouds or soot. -- Under poor conditions, fliers may be able to make use of extensive mapping that has been done on fixed sites in Iraq and Kuwait. Then, using global-positioning navigation, they may be able to find their targets. The bottom line is that much of a flier’s job still depends on eye contact and punching through clouds to achieve the objective. MISSILES: -- In bad or foggy weather, Scud gunners have a better chance of evading searching planes. As a Scud is prepared for launch, a radar signal is emitted. -- In good weather, that signal can be picked up by AWACS intelligence-gathering planes and its location relayed to attack aircraft. But in bad weather, the missile launcher has a better chance of evading attackers by moving after firing.