Late-twentieth-century climatology and trends of surface humidity and temperature in China

Climatological surface temperature and humidity variables for China are pre sented based on 6-hourly data from 196 stations for the period of 1961-90. Seasonal and annual means for daytime, nighttime, and the full day are show n. The seasonal cycle of moisture is primarily controlled by the east Asia monsoon system, with dominant factors of temperature change in northern and western China and of moisture advection associated with monsoon circulatio ns in the southeast. Trends during 1951-94 are estimated for each station and for four regions o f the country, with attention paid to the effects of changes in instrumenta tion, observing time, and station locations. The data show evidence of incr eases in both temperature and atmospheric moisture content. Temperature and specific humidity trends are larger at nighttime than daytime and larger i n winter than summer. Moisture increases are observed over most of China. T he increases are several percent per decade for specific humidity, and seve ral tenths of a degree per decade for temperature and dewpoint. Increasing trends in summertime temperature and humidity contribute to upward trends i n apparent temperature, a measure of human comfort.