The Ningbo-Zhoushan Port in the Yangtze River Delta is highly vulnerable to gales, sea fog, and strong convective weather. [Photo by Zhang Sheng/for chinadaily.com.cn]

A sophisticated early warning system is helping the world's largest port by cargo throughput cut weather-related downtime and keep global supply chains moving, officials said.

Ningbo-Zhoushan Port — the first port in the world to surpass 1 billion metric tons in annual cargo throughput — has held the top global ranking, in terms of cargo throughput, for 16 consecutive years, according to Huang Linlin, deputy director of the traffic management center at the Ningbo Maritime Safety Administration.

The port has managed this feat despite its location in the Yangtze River Delta region, which makes it highly vulnerable to gales, sea fog, and strong convective weather. "Unpredictable conditions can shut down operations for as many as 800 to 1,000 hours annually," Huang said.

To address the problem, the Ningbo meteorological bureau has developed a programmatic early-warning and control system, along with a mobile version. Upgraded last year, the platform integrates meteorological, maritime, port, and hydrological data for real-time sharing and provides minute-by-minute alerts directly to frontline operators.

"It blends forecasts with real-time observations and uses measured data as the basis for more precise management," Huang said.

The Ningbo-Zhoushan Port in the Yangtze River Delta is highly vulnerable to gales, sea fog, and strong convective weather. [Photo by Zhang Sheng/for chinadaily.com.cn]

During Typhoon Co-may in late July, chief forecasters were stationed at the port's dispatch center. As the storm's track shifted, they updated wind forecasts in real time, enabling port managers to adjust work schedules and recover 10 hours of operating time, he said.

The platform has also proved vital for coordinating vessel traffic, according to Lian Sheng, deputy director of operations at the port's dispatch center.

In November, when strong monsoon winds swept the East China Sea, Mediterranean Shipping Co (MSC) — the world's largest container carrier and one of the port's biggest clients — ordered several vessels to skip scheduled calls at Ningbo and Shanghai. Its safety team in Geneva, Switzerland, predicted gales of Beaufort scale 9 to 10 along the coast based on European forecasts.

"That decision meant the ships could not berth as planned," Lian said.

Foreign shipping companies often only see reports of rough seas offshore and are unaware of how different conditions are once vessels enter the port, causing unnecessary losses. For those operating large container vessels, daily charter costs can run into $100,000 per vessel, Lian explained.

"While offshore areas saw severe winds, conditions inside the pocket-shaped harbor dropped by force 1 or 2," Lian said.

After the weather system passed, port officials communicated with MSC and explained that the port's localized forecasting tools determined that the weather inside the harbor was milder than the offshore areas due to the shielding effect of the Zhoushan Islands.

The clarification led to a quick turnaround. During a cold air event this week, MSC relied fully on the port's meteorological guidance, allowing its vessels to enter and leave on schedule. "It shows how precise weather services and smart early warning systems can genuinely empower port operations," he said.

Since 2024, officials have issued 135 targeted warnings for high-impact weather and conducted 65 coordinated operations for traffic control, Huang said.

Port statistics show the early-warning system added an estimated 98 hours of workable time last year and generated 370 million yuan ($51 million) in direct economic benefits.