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Atmospheric and Oceanic Science Letters 2016年第2期9卷 129-138页

作者： WANG Jun yan zhong-wei Key Laboratory of Regional Climate-Environment for Temperate East Asia Institute of Atmospheric PhysicsChinese Academy of Sciences

There have long been arguments about the impact of urbanization on local meteorological observations. This letter reviews up-to-date studies of the urbanization-related warming in the observed land surface air temperature series in China. Many previous studies have suggested that, over the past few decades, the local warming due to urbanization could have been about 0.1 °C/10 yr, or even larger. However, based on recently developed homogenized temperature records, the estimated urban bias is smaller. Major uncertainties arise from either the data quality or the techniques used to estimate the urbanization effect. A key example is the ‘observationminus-reanalysis＇ method, which tends to overestimate the urban signal in this region, partly due to systematic bias in the multi-decadal variability of surface air temperature in the reanalysis data. It is expected that improved numerical modeling with high-resolution information regarding the changing land surface in the region will help to further understand and quantify the effect of urbanization in local temperature records.

关键词： Urbanization China land surface air temperature homogenization observation-minus-reanalysis method uncertainty

Homogenized Daily Mean/Maximum/Minimum Temperature Series for China from 1960-2008

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Atmospheric and Oceanic Science Letters 2009年第4期2卷 237-243页

作者： LI Zhen yan zhong-wei Key Laboratory of Regional Climate-Environment in Temperate East Asia Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

Inhomogeneities in the daily mean/maximum/ minimum temperature （Tm/Tmax/Tmin） series from 1960- 2008 at 549 National Standard Stations （NSSs） in China were analyzed by using the Multiple Analysis of Series for Homogenization （MASH） software package. Typical biases in the dataset were illustrated via the cases of Beijing （B J）, Wutaishan （WT）, Urumqi （UR） and Henan （HN） stations. The homogenized dataset shows a mean warming trend of 0.261/0.193/0.344℃/decade for the annual series of Tm/Tmax/Tmin, slightly smaller than that of the original dataset by 0.006/0.009/0.007℃/decade. However, considerable differences between the adjusted and original datasets were found at the local scale. The adjusted Tmin series shows a significant warming trend almost everywhere for all seasons, while there are a number of stations with an insignificant trend in the original dataset. The adjusted Tm data exhibit significant warming trends annually as well as for the autumn and winter seasons in northern China, and cooling trends only for the summer in the middle reaches of the yangtze River and parts of central China and for the spring in southwestern China, while the original data show cooling trends at several stations for the annual and seasonal scales in the Qinghai, Shanxi, Hebei, and Xinjiang provinces. The adjusted Tmax data exhibit cooling trends for summers at a number of stations in the mid-lower reaches of the yangtze and Yellow Rivers and for springs and winters at a few stations in southwestern China, while the original data show cooling trends at three/four stations for the annual/autumn periods in the Qinghai and Yunnan provinces. In general, the number of stations with a cooling trend was much smaller in the adjusted Tm and Tmax dataset than in the original dataset. The cooling trend for summers is mainly due to cooling in August. The results of homogenization using MASH appear to be robust; in particular, different groups of stations with consideration of elevation led to

关键词： daily mean/maximum/minimum temperature series homogenization China MASH climate trend

Trends in Seasonal Precipitation over China during 1961-2007

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Atmospheric and Oceanic Science Letters 2009年第3期2卷 165-171页

作者： WANG Yi yan zhong-wei Key Laboratory of Regional Climate-Environment Research for Temperate East Asia Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China Graduate University of Chinese Academy of Sciences Beijing 100049 China

Trends in six indices of precipitation in China for seasons during 1961-2007 were analyzed based on daily observations at 587 stations. The trends were estimated by using Sen's method with Mann-Kendall's test for quantifying the significance. The geographical patterns of trends in the seasonal indices of extremes were similar to those of total precipitation. For winter, both total and extreme precipitation increased over nearly all of China, except for a small part of northern China. Increasing trends in extreme precipitation also occurred at many stations in southwestern China for spring and the midlower reaches of the yangtze River and southern China for summer. For autumn, precipitation decreased in eastern China, with an increasing length of maximum dry spell, implying a drying tendency for the post-rainy season. Wetting trends have prevailed in most of western China for all seasons. The well-known 'flood in the south and drought in the north' trend exists in eastern China for summer, while a nearly opposite trend pattern exist for spring.

关键词： climate trend climate extremes indices precipitation dry spell China

A novel scalable synthesis process of PPTA by coupling n-pentane evaporation for polymerization heat removal

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Chinese Chemical Letters 2011年第11期22卷 1379-1382页

作者： Tao Zhang Guo Hua Luo Fei wei yan yan Lu wei zhong Qian Xin Lin Tuo Department of Chemical Engineering Tsinghua University Beijing 100084 China

In this study,we compared the effect of n-pentane and ice-water bath on removing the thermal effect in the poly（p-phenylene terephthalamide）（PPTA） polymerization *** results indicate that the n-pentane can help to transfer the reaction heat faster and *** suitable amount of n-pentanes into the PPTA preparation process not only improve the heat transfer,but also reduce the motor power in the polymerization ***,the introduction of n-pentane properly does not result in decrease of the inherent viscosity（η_（inh）） of ***,it leads to increased viscosity of polymer during the PPTA preparation *** results indicate that n-pentane can effectively transfer the reaction heat and avoid overheating during the polymerization of PPTA.

关键词： PPTA n-Pentane Ice-water bath Reaction heat

Progress in Research on Homogenization of Climate Data

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Advances in Climate Change Research 2012年第2期3卷 59-67页

作者： CAO Li-Juan yan zhong-wei National Meteorological Information Center China Meteorological Administration Beijing 100081 China RCE-TEA Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

The observation data from ground surface meteorological stations is an important basis on which climate change research is carried out, while the homogenization of the data is necessary for improving the quality and homogeneity of the time series. This paper reviews recent advances in the techniques of identifying and adjusting inhomogeneity in climate series. We briefly introduce the results of applying two commonly accepted and well-developed methods (RHtest and MASH) to surface climate observations such as temperature and wind speed in China. We then summarize current progress and problems in this field, and propose ideas for future studies in China. Along with collecting more detailed metadata, more research on homogenization technology should be done in the future. On the basis of comparing and evaluating advantages and disadvantages of different homogenization methods, the homogenized climate data series of the last hundred years should be rebuilt.

关键词： climate observation time series homogeneity uncertainty

Updated Homogenized Chinese Temperature Series with Physical Consistency

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Atmospheric and Oceanic Science Letters 2015年第1期8卷 17-22页

作者： LI Zhen yan zhong-wei WU Hong-Yi Key Laboratory of Regional Climate-Environment in Temperate East Asia Institute of Atmospheric Physics Chinese Academy of Sciences Beijing Meteorological Bureau

Most methods of homogenization of climate data are applied to time series of a single variable, such as daily maximum temperature(Tmax) or daily minimum temperature(Tmin). Consequently, the physical relationship among different variables, e.g., Tmax>Tmin, may be distorted after homogenization of climate series of individual variables. The authors develop a solution to improve consistency among diurnal temperature records, while using the Multiple Analysis of Series for Homogenization(MASH) method to homogenize the observation series of daily mean temperature(Tm), Tmin, and Tmax at 545 stations in China for the period 1960–2011, called CHTM2.0. In the previous version of this homogenized dataset based on MASH(CHTM1.0) for the period 1960–2008, there are a few records(0.039% of the total) that are physically inconsistent. For developing CHTM2.0, the authors apply additional adjustments for each day with inconsistent temperature records, in order to hold Tmax>Tm>Tmin. Although the additional adjustments are barely influential for estimating long-term climate trends in China as a whole(because very few records are additionally adjusted), the newly introduced solution improves the physical consistency throughout the dataset. It is also helpful for developing more reasonable homogenized climate datasets with regard to physical consistency among multiple variables. Based on CHTM2.0, the annual Tmax/Tm/Tmin series averaged over China for the period 1960–2011 show significant warming trends of about 0.19/0.25/0.34°C per decade, respectively. Large warming trends of up to 0.425/0.596/ 0.704°C per decade occur in northeastern and northwestern China.

关键词： diurnal temperature records homogenization physica

Characteristics and Changes of Cold Surge Events over China during 1960-2007

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Atmospheric and Oceanic Science Letters 2009年第6期2卷 339-344页

作者： DING Ting QIAN wei-Hong yan zhong-wei Monsoon and Environment Research Group School of Physics Peking University Beijing 100871 China Key Laboratory of Regional Climate-Environment Research for Temperate East Asia （RCE-TEA） Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China

This paper demonstrates regional characteristics, a long-term decreasing trend, and decadal variations in the frequency of cold surge events based on daily mean temperature and daily minimum temperature data in China's Mainland from 1960 to 2008. During these 48 years four high frequency centers of cold surge events were located in Xinjiang, central North China, northeast China, and southeast China. A main frequency peak of cold surge events occurs in autumn for the four regions and another peak is detected in spring over northeast China and southeast China. The regional pattern of cold surge frequencies is in accordance with the perturbation kinetic energy distribution in October December, January, and February April. The long-term decreasing trend ( 0.2 times/decade) of cold surge frequencies in northeast China and decadal variations in China are related to the variations of the temperature difference between southern and northern China in the winter monsoon season; these variations are due to the significant rising of winter temperatures in high latitudes.

关键词： cold surge extreme event temperature climate change trend

Changes in Local Growing Season Indices in Shanghai Due to Urbanization during 1873–2013

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Atmospheric and Oceanic Science Letters 2015年第6期8卷 383-385页

作者： XIA Jiang-Jiang yan zhong-wei XIONG Zhe Key Laboratory of Regional Climate-Environment for East Asia Institute of Atmospheric Physics Chinese Academy of Sciences

The contribution of urbanization to the changes in growing season indices(e.g.,the start date of the growing season,Ds)in Shanghai,eastern China,for the period 1873–2013 is *** urban-related Ds advancement(referred to as the urbanization contribution,UC)is reconstructed based on the changing urban-land fraction within a grid box around Shanghai for 1873–*** removing the UC from the raw Ds time series,the secular trend(ST)representing the long-term climatic warming and multidecadal variability(MDV)representing an oscillatory component with a period of several decades are obtained by using the Ensemble Empirical Mode Decomposition(EEMD)*** show that the UC is comparable with the contribution of the ST for the period 1873–2013,when Ds exhibits an advancing rate of about 0.44 days per *** plays an important role in regulating changes in Ds on the decadal timescale,e.g.,with a contribution of about 56.1%for1981–2013.

关键词： growing season urbanization multidecadal variabili

A Spatial Cluster Analysis of Heavy Rains in China

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Atmospheric and Oceanic Science Letters 2011年第1期4卷 36-40页

作者： TU Kai yan zhong-wei WANG Yi Key Laboratory of Regional Climate-Environment for East Asia Institute of Atmospheric Physics Chinese Academy of Sciences Beijing 100029 China National Meteorological Center Chinese Meteorological Administration Beijing 100081 China

Clustered heavy rains （CHRs） defined using hierarchical cluster analysis based on daily observations of precipitation in China during 1960-2008 are investi- gated in this paper. The geographical pattern of CHRs in China shows three high-frequency centers--South China, the yangtze River basin, and part of North China around the Bohai Sea. CHRs occur most frequently in South China with a mean annual frequency of 6.8 （a total of 334 times during 1960-2008）. June has the highest monthly frequency （2.2 times/month with a total of 108 times dur- ing 1960-2008）, partly in association with the Meiyu phenomenon in the yangtze River basin. Within the past 50 years, the frequency of CHRs in China has increased significantly from 13.5 to 17.3 times per year, which is approximately 28%. In the 1990s, the frequency of CHRs often reached 19.1 times per year. The geographical extent of CHR has expanded slightly by 0.5 stations, and its average daily rainfall intensity has increased by 3.7 mm d-1. The contribution of CHRs to total rainfall amount and the frequency of daily precipitation have increased by 63.1% and 22.7%, respectively, partly due to a significant decrease in light rains. In drying regions of North and Northeast China, the amounts of minimal CHRs have had no significant trend in recent years, probably due to warming in these arid regions enhancing atmospheric conveetivity at individual stations.

关键词： cluster analysis heavy rain cIimate extremes geographical correlation.