Daily precipitation amounts and frequencies from the CMORPH （Climate Prediction Center Morphing Technique） and TRMM （Tropical Rainfall Measuring Mission） 3B42 precipitation products are validated against warm season in-situ precipitation observations from 2003 to 2008 over the Tibetan Plateau and the regions to its east. The results indicate that these two satellite datasets can better detect daily precipitation frequency than daily precipitation amount. The ability of CMORPH and TRMM 3B42 to accurately detect daily precipitation amount is dependent on the underlying terrain. Both datasets are more reliable over the relatively flat terrain of the northeastern Tibetan Plateau, the Sichuan basin, and the mid-lower reaches of the Yangtze River than over the complex terrain of the Tibetan Plateau. Both satellite products are able to detect the occurrence of daily rainfall events; however, their performance is worse in regions of complex topography, such as the Tibetan Plateau. Regional distributions of precipitation amount by precipitation intensity based on TRMM 3B42 are close to those based on rain gauge data. By contrast, similar distributions based on CMORPH differ substantially. CMORPH overestimates the amount of rain associated with the most intense precipitation events over the mid-lower reaches of the Yangtze River while underestimating the amount of rain associated with lighter precipitation events. CMORPH underestimates the amount of intense precipitation and overestimates the amount of lighter precipitation over the other analyzed regions. TRMM 3B42 underestimates the frequency of light precipitation over the Sichuan basin and the mid-lower reaches of the Yangtze River. CMORPH overestimates the frequencies of weak and intense precipitation over the mid-lower reaches of the Yangtze River, and underestimates the frequencies of moderate and heavy precipitation. CMORPH also overestimates the frequency of light precipitation and underestimates the frequency of intense precipitation over the other three
The regionalization of climate in China is based on a three-level classification in terms of lasting days for accumulated temperature （AT）,aridity index,and July mean temperature.Based on daily meteorological observational data from 756 stations,trends and interdecadal variation in indices for classifying temperature zones,moisture regions and climatic subregions in the period 1961-2010 are discussed.Results reveal that the nationwide AT ≥ 10℃C （AT10） and its lasting days are basically increasing,while aridity in northern Xinjiang is decreasing.The increasing trend of July mean temperature in North China is found to be notably larger than in South China.In terms of their national averages,a marked step increase of AT10 and its lasting period,as well as July mean temperature occurred around 1997,while the aridity index presents no such clear change.By comparing regionalization areas for 1998-2010 with those for 1961-97,it is found that the semi-humid,semi-dry and dry regions in the sub-temperate zone,as well as the humid region in the middle subtropical zone,have experienced substantial shrinkage in terms of area.In contrast,the areas of semi-dry and dry regions in the warm temperate zone,as well as the humid region in the south subtropical zone,present drastically increasing trends.Owing to the influence of such step changes that took place in 1997,that particular point in time should be given close attention in future studies regarding the regionalization of climate in China.
The effect of urban land-use change in eastern China on the East Asian subtropical monsoon（EASTM） is investigated by using the Community Atmosphere Model version 5.1.Comparison of the results between the urban expansion and reference experiments shows that with the urban expansion,the land surface energy balance alters：surface net radiation and sensible heat fluxes enhance while the latent heat fluxes reduce.As a result,a significant increase in surface air temperature over eastern China is detected.The urban land-use change contributes to a change in the zonal land-sea temperature difference（LSTD）,leading to a delay in the time when LSTD changes from positive to negative,and vice versa.Additionally,the onset and retreat dates of the EASTM are also delayed.Meanwhile,the rise in surface air temperature leads to formation of abnormal northerly air flows,which may be the reason for the slower northward movement of the EASTM and a more southward location of its northern boundary.
Based on three global annual mean surface temperature time series and three Chinese annual mean surface air temperature time series,climate change trends on multiple timescales are analyzed by using the trend estimation method of multi-sliding time windows.The results are used to discuss the so-called global-warming hiatus during 1998-2012.It is demonstrated that different beginning and end times have an obvious effect on the results of the trend estimation,and the implications are particularly large when using a short window.The global-warming hiatus during 1998-2012 is the result of viewing temperature series on short timescales;and the events similar to it,or the events with even cold tendencies,have actually occurred many times in history.Therefore,the global-warming hiatus is likely to be a periodical feature of the long-term temperature change.It mainly reflects the decadal variability of temperature,and such a phenomenon in the short term does not alter the overall warming trend in the long term.
