LOS ANGELES (Reuters) - Chinese solar company Trina Solar Ltd raised its shipment and gross margin forecasts for the second quarter on Monday, citing an improvement in the global market for solar power, and announced a 4 million share offering.

The company also gave a revenue forecast that was in line with the estimates of Wall Street analysts. Its stock fell 3.5 percent following the announcement.

Trina's announcement comes as the beleaguered solar industry is beginning to show signs of a turnaround following sharp declines in the price of solar panels due to a dramatic drop in demand aggravated by the financial crisis and a pullback in solar subsidies in Spain.

Trina expects shipments of 63 megawatts to 65 MW for the quarter, up slightly from a previous view of 60 to 65 MW.

Gross margins are expected to be between 26 percent and 28 percent, up from a prior view of 18 percent to 20 percent, Trina said.

The Changzhou, China company also forecast revenue of $148 million to $152 million. Analysts had been expecting revenue of $151.6 million, according to Reuters Estimates.

"Our improved operating performance reflects a steady improvement in the global solar marketplace and a supportive regulatory environment," Trina Chief Executive Jifan Gao said in a statement.

Separately, Trina said it would sell 4 million American depositary shares, the proceeds of which would be used to buy back some of its 4 percent convertible senior notes due 2013 and fund an expansion of its facilities.

Goldman Sachs and Credit Suisse will act as joint bookrunners for the sale and Piper Jaffray will act as co-manager.

Trina shares fell to $28.81 after hours after closing at $29.87 on the New York Stock Exchange.

(Reporting by Nichola Groom; editing by Andre Grenon)