Seasonal Rainfall Forecasts for the Yangtze River Basin of China in Summer 2019 from an Improved Climate Service

• 作者: Adam A. SCAIFE Chaofan LI Chris D. HEWITT Gill M. MARTIN Hong-Li REN Joanne CAMP Leon HERMANSON Min LIU Nick DUNSTONE Nicola GOLDING Nicola MARTIN Peiqun ZHANG Philip E. BETT Ying LIU
• 来源期刊: 气象学报（英文版）
• 年，卷（期）: 2020,（5）
• 所属期刊栏目: SPECIAL COLLECTION ON CLIMATE SCIENCE FOR SERVICE PARTNERSHIP (CSSP) CHINA
• 页码范围: 904-916,中插1-中插3
• 页数: 1页
• 语种: 英文

摘要

Rainfall forecasts for the summer monsoon season in the Yangtze River basin (YRB) allow decision-makers to plan for possible flooding, which can affect the lives and livelihoods of millions of people. A trial climate service was de-veloped in 2016, producing a prototype seasonal forecast product for use by stakeholders in the region, based on rain-fall forecasts directly from a dynamical model. Here, we describe an improved service based on a simple statistical downscaling approach. Through using dynamical forecast of an East Asian summer monsoon (EASM) index, seaso-nal mean rainfall for the upper and middle/lower reaches of YRB can be forecast separately by use of the statistical downscaling, with significant skills for lead times of up to at least three months. The skill in different sub-basin re-gions of YRB varies with the target season. The rainfall forecast skill in the middle/lower reaches of YRB is signific-ant in May–June–July (MJJ), and the forecast skill for rainfall in the upper reaches of YRB is significant in June–July–August (JJA). The mean rainfall for the basin as a whole can be skillfully forecast in both MJJ and JJA. The fore-casts issued in 2019 gave good guidance for the enhanced rainfall in the MJJ period and the near-average conditions in JJA. Initial feedback from users in the basin suggests that the improved forecasts better meet their needs and will enable more robust decision-making.