Tropical cyclone- and monsoon-induced rainfall variability over southern China

November 28, 2016, Chinese Academy of Sciences

Southern China (SC) belongs to the East Asian summer monsoon region. Climatological rainfall over SC has two peaks, one appearing in April-June and the other in August-September. These peaks are mainly associated with the summer monsoon and the passage of tropical cyclones (TCs), respectively. TCs forming in the South China Sea (SCS) contributed to an increase in SC summer rainfall around 1993. In Taiwan, tropical cyclone-induced precipitation (PTC) and summer monsoon-induced precipitation (PSM) tend to vary inversely on both interdecadal and interannual time scales. Although SC and Taiwan are situated at almost the same latitude, scientists from Sun Yat-Sen University and South China Sea Institute of Oceanology pointed out that the relationship over SC between PTC and PSM is different from that in Taiwan. The results are published in Atmospheric and Oceanic Science Letters.

The spatial patterns of the first interannual mode are uniform in sign over SC, with positive anomalies for PTC and negative anomalies for PSM. The background of an increase in cyclonic vorticity, an increase in RH, and a decrease in vertical wind shear over the South China Sea (SCS)-western north Pacific (WNP) provides favorable conditions for more TC genesis. The positive equatorial central Pacific SST anomaly and negative North Indian Ocean SST anomaly contribute to the anomalous cyclone over the SCS-WNP, which causes decreasing PSM in SC together with an anomalous anticyclone over eastern China-Japan.

By contrast, the interdecadal eigenvectors feature uniform patterns with positive anomalies for both PTC and PSM. During the preceding winter and spring after the early 1990s, a positive western Pacific SST anomaly can result in tropical Indian Ocean (TIO) SST warming through vertical circulation. Then, the positive TIO SST anomaly triggers an anomalous WNP anticyclone and contributes to the interdecadal increase in SC PSM in the succeeding . The increase in PTC over SC is related to more TCs forming in the SCS. These results lend greater insight into the variability of SC summer rainfall through separating total rainfall into PTC and PSM.

Explore further: South China Sea summer monsoon onset

More information: Jie-Peng CHEN et al, Relationship over southern China between the summer rainfall induced by tropical cyclones and that by monsoon, Atmospheric and Oceanic Science Letters (2016). DOI: 10.1080/16742834.2017.1248756

Related Stories

South China Sea summer monsoon onset

November 9, 2016

The South China Sea summer monsoon (SCSSM) greatly influences the socioeconomics of the regions it affects. Its onset mechanism is therefore a popular topic among atmospheric science researchers. However, due to the complexity ...

Recommended for you

Squid could provide an eco-friendly alternative to plastics

February 21, 2019

The remarkable properties of a recently-discovered squid protein could revolutionize materials in a way that would be unattainable with conventional plastic, finds a review published in Frontiers in Chemistry. Originating ...

Female golden snub-nosed monkeys share nursing of young

February 21, 2019

An international team of researchers including The University of Western Australia and China's Central South University of Forestry and Technology has discovered that female golden snub-nosed monkeys in China are happy to ...

When does one of the central ideas in economics work?

February 20, 2019

The concept of equilibrium is one of the most central ideas in economics. It is one of the core assumptions in the vast majority of economic models, including models used by policymakers on issues ranging from monetary policy ...

In colliding galaxies, a pipsqueak shines bright

February 20, 2019

In the nearby Whirlpool galaxy and its companion galaxy, M51b, two supermassive black holes heat up and devour surrounding material. These two monsters should be the most luminous X-ray sources in sight, but a new study using ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.