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Based on the data of five observed meteorological elements (temperature, precipitation, wind speed, sunshine duration, and relative humidity) from 22 stations, the paper investigated the climate variations in northern Xinjiang over the past 50 years. The analytical results showed that both the temperature and the precipitation have increased significantly (0.35 °C/10 y, 11.2 mm/10 y) during the period of 1960–2011. An abrupt change was detected to have occurred in 1986 for temperature and in 1987 for precipitation. Autumn was the season when the temperature increased most dramatically, and winter and autumn were the seasons when the precipitation increased most dramatically. The twenty years after 1990 were the warmest and wettest two decades of the past ∼50 years, but the warming and wetting paces have slowed down during the same period. The results also showed that the mean annual minimum temperature increased more dramatically than the mean annual maximum temperature, resulting in a greatly reduced diurnal range. The reasons or mechanisms for rising trend of temperature during the past 50 years and also for the faster rising rate of the temperature in northern Xinjiang and the adjacent areas have been reasonably explored in published literature. However, the reasons or mechanisms for the rising trend of the past 50-year precipitation in northern Xinjiang and the adjacent areas have not been reasonably explored. This wetting trend has not extended further to the surrounding areas including Republic of Mongolia, major part of North China, and five republics of the former Soviet Union, and the need is thus pressing to explore the reasons or mechanisms behind this relatively “localized” wetting trend. [ABSTRACT FROM AUTHOR]

Abstract: This paper quantifies the contribution of climatic factors to potential evapotranspiration (ET0) under different drought periods by making use of the FAO Penman–Monteith method, linear regression analysis, Mann–Kendall test, and the drought classification derived from the Standardized Precipitation Index (SPI). ET0 and meteorological data from 93 North China weather stations from 1961 to 2010 located in a semi-arid climate zone were analyzed. The annual ET0 values showed a significantly increasing trend with the aggravation of drought. Results indicated that in drought periods, temperature and sunshine hours had positive effects on the variation of ET0, while other key climatic factors (i.e. effective precipitation, vapor pressure, wind speed, relative humidity) had negative effects on ET0. ET0 was most sensitive to effective precipitation and mean daily temperature, with sensitivity rates of −4.163 and 1.368 respectively. The sensitivities of ET0 decreased over time in the drought period, which was caused by the joint effects of the climatic factors. The decreasing sensitivity of wind speed and relative humidity increased the ET0, and the increase of daily temperature produced the majority of rise in ET0 rates. The decrease of wind speed and relative humidity resulted in positive contributions to ET0. The increase in the sensitivity of precipitation and vapor pressure resulted in strongly decreased ET0, and the decrease of sunshine hours resulted in little change in ET0 rates. [Copyright &y& Elsevier]

Abstract: Drought is a recurring phenomenon in north-central China. Long-term information about the history of drought is still limited because the instrumental records for many areas in north-central China go back only a few decades at best. This paper presents an earlywood width (EWW) chronology of Chinese pine (Pinus tabulaeformis) in the Shimen Mountains, Tianshui, eastern Gansu, north-central China. The climate-response analysis shows that April–July precipitation is the main factor limiting the earlywood growth of Chinese pines in the Shimen Mountains, Tianshui. Based on the EWW chronology, an April–July precipitation reconstruction for the period A.D. 1629–2008 was developed for Tianshui. The climate/tree-growth model accounts for 41.6% of the observed precipitation variance during the period 1953–2008. Spatial analysis shows that the precipitation reconstruction contains a strong common drought signal for north-central China. Reconstructed drought events are compared to a precipitation reconstruction of Huashan and historical archives for north-central China. The results reveal common climatic extremes over much of north-central China. Moreover, some dry periods coincided with solar minima or volcanic eruptions over the past several hundred years. Multi-taper spectral analysis reveals the existence of significant 3.8-year (90%), 3.1-year (95%), 2.7-year (99%), 2.4-year (99%) and 2.0-year (99%) periods of variability. The linkages to the Asian-Pacific Oscillation Index suggest regional precipitation variations may be linked to the East Asian summer monsoon circulations. [Copyright &y& Elsevier]

Abstract: This study focuses on extreme temperature and extreme precipitation changes in Guangxi Province of south China, which has experienced increased numbers of climate disasters in recent years. In this paper, spatial and temporal changes in extreme temperature and extreme precipitation were reconstructed for the period 1960–2009. The method of FFT filtering was used to smooth time series of extreme temperature and extreme precipitation, linear regression to calculate linear fits, and spline interpolation to interpolate station data and estimate linear changes. The results show that the annual extreme temperature increased in most of the area during 1960–2009, especially in the northeast. The greatest increase was the extreme temperature in winter, compared to that in autumn, summer and spring in order from high to low across most of the study area. The annual extreme precipitation changed little in the first three decades and increased significantly in the last two decades, and varied with region and season. Spatially, the annual trend of extreme precipitation increased across most of the province, except in some areas of the southeast. The seasonal change trend of extreme precipitation varied greatly across different areas. [Copyright &y& Elsevier]

Abstract: Tropical cyclones (TCs) are historically documented along the coastline of China. They can have negative impacts on society and damages are reported annually. This paper examines to what extent TCs are responsible for heavy rain days (precipitation > 100 mm/d) in coastal Fujian Province. The average deviation of TCs making landfall in China is 25%, and they occur more reliably than TCs in the west North Pacific. A distinct typhoon season between July and September/October was detected and can be explained by low interannual variability during these months. The annual number of TCs is below average (above average) during El Niño (La Niña) years, but the intensity of TCs is higher during El Niño years. From 1960 to 2007, 41% of heavy rain days (precipitation > 100 mm/d) at all 66 weather stations in Fujian Province were triggered by TCs. The number of heavy rain days is higher during El Niño years, although the number of TCs affecting Fujian in general is higher during La Niña years. For the coastal weather stations in east Fujian, 57% (45%) of the heavy rain days are triggered by TCs during El Niño (La Niña) years. In the research area, more than 50% of annual heavy rain days can be explained by TCs, and the ratio reaches 85% in the northern part bordering Zhejiang Province. More TCs impact Fujian during La Niña years, but more TCs cause heavy precipitation days during El Niño years. The number of heavy rain days fluctuates in line with the interannual variability of TCs making landfall. [ABSTRACT FROM AUTHOR]