Hu, Z-Z., S. Yang, and R. Wu, 2003:
Long-term climate variations in China and global warming signals

COLA Technical Report No. 141, Center for Ocean-Atmosphere-Land Studies, Calverton, Maryland, USA, 36 pp.

Abstract

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In this work, the authors firstly analyze the observed long-term variations of seasonal

climate in China, and then investigate the possible influence of the increase in greenhouse

gas concentrations on these variations by comparing the observations with the simulations

of the second phase of the Coupled Model Intercomparison Project (CMIP2).

The long-term variations of precipitation and temperature in China are highly seasonally

dependent. The main characteristic of summer precipitation in China is a drying trend in

the north and a wetting trend in the central part. The precipitation in winter shows an

increasing trend in South and eastern-central China. Interesting features have also been

found in the transitional seasons. In spring, precipitation variations are almost opposite to

those in summer. In autumn, the precipitation decreases in almost the whole country, except

for the middle and lower reaches of the Yangtze River Valley. In addition, the seasonality of

precipitation becomes slightly weaker in recent decades in southern and eastern China.

Pronounced warming is observed in the entire country in winter, spring, and autumn,

particularly in the northern part of China. In summer, a cooling trend in central China

is particularly interesting. The variations of seasonal-mean temperature are strong coupled

with those of precipitation. Cooling (warming) trends generally coexist with wetting (drying)

trends. The coupling becomes weaker in the other seasons. It has also found that the long-

term climate variations in China may be connected to the warming trend in the Indian

Ocean.

A comparison between the observed seasonal climate variations and the CMIP2 simula-

tions of 16 models indicates that the observed long-term variations of winter temperature

in China are associated with the increase in greenhouse gas concentrations. However, such

a connection has not been found for the summer temperature. The tremendous uncertain-

ties among the models in precipitation simulations make it difficult to link the precipitation

variations to the global warming.

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