BOSTON — A giant aerial sculpture is floating over a park in Boston’s Financial District, bringing a shimmer of spring where snowplow piles towered just weeks ago. On Monday, dozens of workers closed nearby streets and set to work installing the 600-foot work by artist Janet Echelman, using a battery of cranes and scissor lifts. The orange and magenta netting made of polyethylene rope weighs a ton, and is designed to respond fluidly to wind and weather. It will remain suspended in the Rose Kennedy Greenway between two high-rise buildings across the Greenway through October. Echelman is based in suburban Brookline. Her sculpture — which includes more than 100 miles of twine — is inspired by ancient fishing nets. She has installed similar works in Seattle; Madrid, Spain; Amsterdam, Netherlands; Sydney, Australia; and other cities. — AP