BEIJING, March 20 -- The following is a summary of published science and technology news of China.

COVID-19 VACCINES

Positive progress has been made in the development of monovalent and multivalent vaccines against the Omicron variants, a senior Chinese health official told a press conference on Saturday.

Pre-clinical studies for some vaccines have been completed, with applications for clinical trials in progress, said Zheng Zhongwei, an official with the National Health Commission.

"Studies show that the Omicron variant has not completely escaped the existing vaccines," Zheng said, noting that complete vaccination is still effective in reducing the risk of hospitalization, severe illness and death caused by Omicron variants.

METHANE EMISSIONS

Tropical terrestrial emissions could explain more than 80 percent of the observed changes in the global atmospheric methane growth rate over the 2010-2019 period, showed the latest study by a joint research team.

Methane concentration in the atmosphere has more than doubled since the pre-industrial era, contributing 20 percent of present-day human-induced global warming. according to Liu Yi, a researcher with the Institute of Atmospheric Physics of the Chinese Academy of Sciences.

Tropical terrestrial methane emissions, as the main contributor, represent about 60 percent of the global totals and describe 84 percent of the global annual mean growth rate in the 2010s, said the study published online in the journal Nature Communications.

ROOFTOP PHOTOVOLTAIC

Cainiao Network, Alibaba's logistics arm, switched on the new rooftop photovoltaic (PV) power generation facilities at its bonded warehouses in east China's Zhejiang Province on Thursday.

Spanning over 100,000 square meters, the rooftop PV panels glinted in the sun at the company's two major bonded warehouses: Hangzhou Comprehensive Bonded Zone in the provincial capital of Hangzhou; and Ningbo Qianwan Comprehensive Bonded Zone in the city of Ningbo.

The PV power systems can produce about 8 million kilowatt-hours (kWh) of electricity annually, equivalent to the yearly electricity consumption of over 3,000 households.

  - Xinhua