The Defense Department has awarded Jacobs Engineering Group Inc. and Northrop Grumman Corp. contracts on separate Air Force and Navy projects.

Jacobs Technology Inc., the advanced technology division of Pasadena-based Jacobs Engineering, was awarded a contract modification worth $103 million for its support work at Eglin Air Force Base in Florida.

Northrop won a $9.8 million Air Force contract to replace narrow-band klystron power amplifiers for radar equipment for the Saudi Arabia and French Airborne Warning and Control System fleets.

The Los Angeles defense contractor also received a $42.4 million Navy contract for work on submarine and surface ships. It will supply engineering, technical analysis and testing services at naval shipyards and fleet ports worldwide.

Northrop shares were down 78 cents, or 1 percent, to $56.59, and Jacobs was down 3 cents or less than 1 percent to $35.37 in midday trading Monday on the New York Stock Exchange.