Heat 1/2 cup broth to a simmer in a medium saucepan over medium-high heat. Add onion and garlic and cook until tender, about 6 minutes, stirring occasionally. Stir in ginger, carrots, potato and remaining broth and heat to a boil. Reduce to a simmer, cover and cook 25 minutes or until vegetables are tender.In batches, carefully puree in a blender. Add water or broth if needed to thin to desired consistency. Reheat soup if necessary. Stir in lemon juice and garnish with chives.