近50年青藏高原地面气温变化的区域特征分析

青藏高原地面气温与其上空500hPa温度有着密切的关系，基于这种关系，重建得到青藏高原19502000年连续、可靠的台站地面月平均气温序列。利用重建后的地面月平均气温资料，对青藏高原年及各季节平均气温的变化进行区域划分，分析了近50年青藏高原全年及各季节气温变化的区域特征。结果表明，青藏高原的年、春、夏、秋季与冬季平均气温变化区域分别可以划分为4个区、2个区、4个区、5个区和4个区。青藏高原近50年气温总体上升，但同时存在明显的区域性和季节性差异，大部分区域的平均气温变化和高原总体升温相似，春季和冬季升温明显，特别是春季和冬季的Ⅰ区。夏、秋季升温趋势不明显，夏季Ⅰ区与秋季Ⅲ区还表现出较小的降温趋势，降温幅度分别为-0．26℃和-0．11℃。     

近40年西藏定日县气温变化特征分析

根据1971²010年西藏定日站的平均气温、最高、最低气温的逐月资料,分析了该地区近40a来气温变化特征。结果表明:近40年来定日县的年及各季节的平均气温均呈明显的上升趋势,其中,年平均气温的线性倾向率为0.394℃/10a,冬季平均气温的升温幅度最大,其次是春季和秋季,夏季的升温幅度最小。年平均最高、最低气温与年平均气温的变化趋势一致,均呈上升趋势,年平均最高气温线性倾向率为0.372℃/10a;年平均最低气温线性倾向率为0.445℃/10a,最低气温的上升速率高于最高气温。不同时段的平均气温基本上在1997年之后上升趋势非常明显,最高、最低气温在20世纪90年代以后才出现温度的上升突变。     

中国北极村气候变暖特征

利用我国最北部的北极村气象站1963～2005年气温资料,通过计算气候倾向率和气候趋势系数,对该地区气候变化特点进行了分析。结果表明,43年来北极村气温有明显并稳定的上升趋势,年平均气温以每10年0．46℃幅度升高。各季及逐月平均气温都存在不同程度的变暖趋势,但是冬季升温最为剧烈,达每10年0．69℃,其中2月升温幅度为每10年1．02℃,为全年最大。秋季升温最弱,仅为每10年0．21℃。年平均最低气温（每10年0．59℃）和年极端最低气温（每10年0．74℃）比年平均最高气温（每10年0．37℃）和年极端最高气温（每10年0．27℃）升温幅度明显偏大。最低气温比最高气温对平均气温的年代际升温趋势贡献更为明显。     

玉树地区近50年气温变化分析

利用玉树地区1957-2007年的逐月气温资料用气候均值和均方差方法计算了线性趋势系数,并采用蒙特卡洛显著性检验对玉树地区近50年来冬季、秋季、春季和夏季气温进行了分析,结果表明：玉树地区气温变化率呈逐渐上升趋势,其中秋季、春季气温上升趋势最为明显,年平均气温以0．23℃／10年的速度升温,高于青海省年平均气温变化线性趋势系数为0．16℃／10年。     

河南省冷暖变化气候特征分析

利用河南省107个观测站1961-2006年46 a的气温观测资料,分析了河南省冷暖变化的年际和年代际特征及其区域差异和季节差别.结果表明:河南省年平均气温、年平均最高气温、年平均最低气温的年际和年代际变化都呈现增温趋势,增温幅度由大到小依次为年平均最低气温、年平均气温、年平均最高气温;全省7个气候分区年平均气温、最低气温变化趋势具有整体一致性,都呈现升温趋势,但各区域的增温幅度不一,增幅最大的区域是太行山气候区,最小的区域是豫西山地气候区.平均最高气温南阳盆地、淮北平原、豫北平原3个气候区呈略降趋势,其他4个气候区呈升温趋势,豫西山地气候区增幅最大;各季气温变化呈现春、秋季平均气温变化幅度相对比较平缓、冬季增温幅度最大的特点,自20世纪90年代初始,暖冬现象明显;在全球和中国气候将继续变暖的背景下,河南省平均气温按10 a增加0.22℃计,估计未来50 a升高1～2℃.     

近46年重庆地区气温变化特征分析

利用1961-2006年期间重庆地区的气温资料,对重庆气温变化的特征进行分析。结果表明：近46年,重庆年平均、年平均最高气温都经历了先降温后升温的过程,而且前期1961—1985年的降温趋势和后期1986—2006年的升温趋势都很显著,均通过了0．01的显著性水平检验。而年平均最低气温近46年的整体上升趋势明显,通过了0．01的显著性水平检验。对于重庆平均气温和平均最高气温,在前期降温过程中,春季和夏季的下降趋势显著;而在后期的升温过程中,春季和秋季的增温趋势显著。     

朔州市气温和降水变化特征分析

朔州市的年平均气温、年平均最高气温、年平均最低气温自20世纪70年代中期以来呈上升趋势，进入90年代后，这种趋势有所加快，尤其以冬季升温最为明显。年平匀气温以0．43℃／10a的速度上升；平均最低气温升温幅度明显高于平均最高气温；年平均降水量略呈下降趋势，主要是由夏季降水减少所致。     

1961—2013年石家庄市气温变化特征分析

文章利用石家庄市1961—2013年气温资料,采用滑动平均、线性趋势图、M-K突变检验等方法对石家庄近53a的气温变化特征进行了分析。结果表明:近53a平均气温上升趋势明显,20世纪80年代后期升温显著;年平均最高气温增温率仅为0.107℃/10a,增温趋势平缓,而年平均最低气温增温率为0.594℃/10a,呈明显的逐年上升趋势,说明气候变暖趋势显著;高温日数的增加,气候变暖趋势已成为必然。四季平均气温呈线性上升趋势,春季、冬季变化幅度最大且具有继续升温的趋势,是造成气候变暖的主要原因。而夏季、秋季变化幅度较小。     

青海省近50年来的气温变化特征初探

通过对青海省1961—2010年27站的年平均气温,年最高、最低等气温资料的分析,得出近50a来青海省气温随时间的变化趋势特征。用滑动平均和一次线性倾向估计来描述气温的年际变化趋势,采用Mann—Kendall法来检验气温突变现象。分析发现:(1)在全球变暖的大背景下,近50a来青海省年平均气温呈上升趋势,年平均气温升温率为0.13℃/10a,21世纪升温幅度达到最大,为0.6℃。2006年是50a来年平均气温最高的1a,年平均气温比60年代际平均气温升高了2.14℃;(2)年平均最高、最低气温变化有着明显的不对称性,并且最低气温较最高气温的升温更为明显;(3)气温变化存在着显著的季节性差异。冬季的增温比夏季明显。气温在各年代际间的变化趋势也不一致,从升温率也可以看到,冬季升温幅度比较大,50a来的平均气温升温率为1.19℃。而夏季的升温率为-0.22℃;(4)通过MK检验得出:20世纪90年代初及中期以及21世纪初青海省年平均及1月、7月平均气温发生了一次显著的变暖突变。     

聊城市1962—2011年气温变化特征分析

运用常规统计方法、线性拟合方法、累积距平方法等分析了1962—2011年聊城市8个国家气象站50a气温资料的变化特征。结果表明：春季、秋季、冬季平均气温都随时间呈线性增加的趋势,年平均气温增温速率为0．18℃／10a,各季增温速率从大到小依次为冬季、秋季、春季,而夏季则呈现一定程度的弱降温趋势;年极端最高气温变化趋势以1994年为分界点前后分为一个降温阶段和一个升温阶段;年极端最低气温整体呈波动上升,分为4个降温阶段和3个升温阶段;冷指数即冷事件频率呈减少趋势,且从20世纪80年代中后开始显著减少,而暖指数则以增加趋势为主,但开始发生显著变化的年代在90年代中期。     

CHARACTERISTICS AND TRENDS OF CLIMATIC EXTREMES IN CHINA DURING 1959–2014

The spatial and temporal variations of daily maximum temperature(Tmax), daily minimum temperature(Tmin), daily maximum precipitation(Pmax) and daily maximum wind speed(WSmax) were examined in China using Mann-Kendall test and linear regression method. The results indicated that for China as a whole, Tmax, Tmin and Pmax had significant increasing trends at rates of 0.15℃ per decade, 0.45℃ per decade and 0.58 mm per decade,respectively, while WSmax had decreased significantly at 1.18 m·s~(-1) per decade during 1959—2014. In all regions of China, Tmin increased and WSmax decreased significantly. Spatially, Tmax increased significantly at most of the stations in South China(SC), northwestern North China(NC), northeastern Northeast China(NEC), eastern Northwest China(NWC) and eastern Southwest China(SWC), and the increasing trends were significant in NC, SC, NWC and SWC on the regional average. Tmin increased significantly at most of the stations in China, with notable increase in NEC, northern and southeastern NC and northwestern and eastern NWC. Pmax showed no significant trend at most of the stations in China, and on the regional average it decreased significantly in NC but increased in SC, NWC and the mid-lower Yangtze River valley(YR). WSmax decreased significantly at the vast majority of stations in China, with remarkable decrease in northern NC, northern and central YR, central and southern SC and in parts of central NEC and western NWC. With global climate change and rapidly economic development, China has become more vulnerable to climatic extremes and meteorological disasters, so more strategies of mitigation and/or adaptation of climatic extremes,such as environmentally-friendly and low-cost energy production systems and the enhancement of engineering defense measures are necessary for government and social publics.     

Could the Recent Taal Volcano Eruption Trigger an El Ni?o and Lead to Eurasian Warming?

正The Taal Volcano in Luzon is one of the most active and dangerous volcanoes of the Philippines. A recent eruption occurred on 12 January 2020(Fig. 1a), and this volcano is still active with the occurrence of volcanic earthquakes. The eruption has become a deep concern worldwide, not only for its damage on local society, but also for potential hazardous consequences on the Earth's climate and environment.     

VARIABILITY OF INTER-ANNUAL RELATIONSHIP BETWEEN INDIAN OCEAN DIPOLE AND HUAXI REGION’S AUTUMN PRECIPITATION

The moving-window correlation analysis was applied to investigate the relationship between autumn Indian Ocean Dipole (IOD) events and the synchronous autumn precipitation in Huaxi region, based on the daily precipitation, sea surface temperature (SST) and atmospheric circulation data from 1960 to 2012. The correlation curves of IOD and the early modulation of Huaxi region’s autumn precipitation indicated a mutational site appeared in the 1970s. During 1960 to 1979, when the IOD was in positive phase in autumn, the circulations changed from a “W” shape to an ”M” shape at 500 hPa in Asia middle-high latitude region. Cold flux got into the Sichuan province with Northwest flow, the positive anomaly of the water vapor flux transported from Western Pacific to Huaxi region strengthened, caused precipitation increase in east Huaxi region. During 1980 to 1999, when the IOD in autumn was positive phase, the atmospheric circulation presented a “W” shape at 500 hPa, the positive anomaly of the water vapor flux transported from Bay of Bengal to Huaxi region strengthened, caused precipitation ascend in west Huaxi region. In summary, the Indian Ocean changed from cold phase to warm phase since the 1970s, caused the instability of the inter-annual relationship between the IOD and the autumn rainfall in Huaxi region.     

ANALYSIS OF “BIMODAL PATTERN” STORM ACTIVITY CHARACTERISTICS OF THE BAY OF BENGAL

Storms that occur at the Bay of Bengal (BoB) are of a bimodal pattern, which is different from that of the other sea areas. By using the NCEP, SST and JTWC data, the causes of the bimodal pattern storm activity of the BoB are diagnosed and analyzed in this paper. The result shows that the seasonal variation of general atmosphere circulation in East Asia has a regulating and controlling impact on the BoB storm activity, and the “bimodal period” of the storm activity corresponds exactly to the seasonal conversion period of atmospheric circulation. The minor wind speed of shear spring and autumn contributed to the storm, which was a crucial factor for the generation and occurrence of the “bimodal pattern” storm activity in the BoB. The analysis on sea surface temperature (SST) shows that the SSTs of all the year around in the BoB area meet the conditions required for the generation of tropical cyclones (TCs). However, the SSTs in the central area of the bay are higher than that of the surrounding areas in spring and autumn, which facilitates the occurrence of a “two-peak” storm activity pattern. The genesis potential index (GPI) quantifies and reflects the environmental conditions for the generation of the BoB storms. For GPI, the intense low-level vortex disturbance in the troposphere and high-humidity atmosphere are the sufficient conditions for storms, while large maximum wind velocity of the ground vortex radius and small vertical wind shear are the necessary conditions of storms.     

LOW-FREQUENCY CIRCULATION AND EXTENDED-RANGE FORECAST IN CONNECTION WITH AUTUMN EXTREME HEAVY RAINFALL PROCESS IN HAINAN

Observed daily precipitation data from the National Meteorological Observatory in Hainan province and daily data from the National Centers for Environmental Prediction/National Center for Atmospheric Research (NCEP/NCAR) reanalysis-2 dataset from 1981 to 2014 are used to analyze the relationship between Hainan extreme heavy rainfall processes in autumn (referred to as EHRPs) and 10–30 d low-frequency circulation. Based on the key low-frequency signals and the NCEP Climate Forecast System Version 2 (CFSv2) model forecasting products, a dynamical-statistical method is established for the extended-range forecast of EHRPs. The results suggest that EHRPs have a close relationship with the 10–30 d low-frequency oscillation of 850 hPa zonal wind over Hainan Island and to its north, and that they basically occur during the trough phase of the low-frequency oscillation of zonal wind. The latitudinal propagation of the low-frequency wave train in the middle-high latitudes and the meridional propagation of the low-frequency wave train along the coast of East Asia contribute to the ‘north high (cold), south low (warm)’ pattern near Hainan Island, which results in the zonal wind over Hainan Island and to its north reaching its trough, consequently leading to EHRPs. Considering the link between low-frequency circulation and EHRPs, a low-frequency wave train index (LWTI) is defined and adopted to forecast EHRPs by using NCEP CFSv2 forecasting products. EHRPs are predicted to occur during peak phases of LWTI with value larger than 1 for three or more consecutive forecast days. Hindcast experiments for EHRPs in 2015–2016 indicate that EHRPs can be predicted 8–24 d in advance, with an average period of validity of 16.7 d.     

AN ATTRIBUTION ANALYSIS OF CHANGES IN POTENTIAL EVAPOTRANSPIRATION IN THE BEIJING–TIANJIN–HEBEI REGION UNDER CLIMATE CHANGE

Based on the measurements obtained at 64 national meteorological stations in the Beijing–Tianjin–Hebei (BTH) region between 1970 and 2013, the potential evapotranspiration (ET0) in this region was estimated using the Penman–Monteith equation and its sensitivity to maximum temperature (Tmax), minimum temperature (Tmin), wind speed (Vw), net radiation (Rn) and water vapor pressure (Pwv) was analyzed, respectively. The results are shown as follows. (1) The climatic elements in the BTH region underwent significant changes in the study period. Vw and Rn decreased significantly, whereas Tmin, Tmax and Pwv increased considerably. (2) In the BTH region, ET0 also exhibited a significant decreasing trend, and the sensitivity of ET0 to the climatic elements exhibited seasonal characteristics. Of all the climatic elements, ET0 was most sensitive to Pwv in the fall and winter and Rn in the spring and summer. On the annual scale, ET0 was most sensitive to Pwv, followed by Rn, Vw, Tmax and Tmin. In addition, the sensitivity coefficient of ET0 with respect to Pwv had a negative value for all the areas, indicating that increases in Pwv can prevent ET0 from increasing. (3) The sensitivity of ET0 to Tmin and Tmax was significantly lower than its sensitivity to other climatic elements. However, increases in temperature can lead to changes in Pwv and Rn. The temperature should be considered the key intrinsic climatic element that has caused the "evaporation paradox" phenomenon in the BTH region.     

Revisiting the Concentration Observations and Source Apportionment of Atmospheric Ammonia

正While China’s Air Pollution Prevention and Control Action Plan on particulate matter since 2013 has reduced sulfate significantly, aerosol ammonium nitrate remains high in East China. As the high nitrate abundances are strongly linked with ammonia, reducing ammonia emissions is becoming increasingly important to improve the air quality of China. Although satellite data provide evidence of substantial increases in atmospheric ammonia concentrations over major agricultural regions, long-term surface observation of ammonia concentrations are sparse. In addition, there is still no consensus on     

全球贸易隐含碳变化及其影响分析

基于最新的GTAP8 (Global Trade Analysis Project）数据库,使用投入产出法,分析了2004年到2007年全球贸易变化下南北集团贸易隐含碳变化及对全球碳排放的影响。结果显示,随着发展中国家进出口规模扩张,全球贸易隐含碳流向的重心逐渐向发展中国家转移。2004年到2007年,发达国家高端设备制造业和服务业出口以及发展中国家资源、能源密集型行业及中低端制造业出口的趋势加强,该过程的生产转移导致全球碳排放增长4.15亿t,占研究时段全球贸易隐含碳增量的63%。未来发展中国家的出口隐含碳比重还将进一步提高。贸易变化带来的南北集团隐含碳流动变化对全球应对气候变化行动的影响日益突出,发达国家对此负有重要责任。     

COMPARATIVE ANALYSIS OF VARIOUS DATA OF AIR–SEA TEMPERATURE DIFFERENCE AND ITS VARIATION ACROSS SOUTH CHINA SEA IN THE PAST 35 YEARS

Using the International Comprehensive Ocean-Atmosphere Data Set(ICOADS) and ERA-Interim data, spatial distributions of air-sea temperature difference(ASTD) in the South China Sea(SCS) for the past 35 years are compared,and variations of spatial and temporal distributions of ASTD in this region are addressed using empirical orthogonal function decomposition and wavelet analysis methods. The results indicate that both ICOADS and ERA-Interim data can reflect actual distribution characteristics of ASTD in the SCS, but values of ASTD from the ERA-Interim data are smaller than those of the ICOADS data in the same region. In addition, the ASTD characteristics from the ERA-Interim data are not obvious inshore. A seesaw-type, north-south distribution of ASTD is dominant in the SCS; i.e., a positive peak in the south is associated with a negative peak in the north in November, and a negative peak in the south is accompanied by a positive peak in the north during April and May. Interannual ASTD variations in summer or autumn are decreasing. There is a seesaw-type distribution of ASTD between Beibu Bay and most of the SCS in summer, and the center of large values is in the Nansha Islands area in autumn. The ASTD in the SCS has a strong quasi-3a oscillation period in all seasons, and a quasi-11 a period in winter and spring. The ASTD is positively correlated with the Nio3.4 index in summer and autumn but negatively correlated in spring and winter.     

Retrieval of outgoing longwave radiation from COMS narrowband infrared imagery

Hourly outgoing longwave radiation(OLR) from the geostationary satellite Communication Oceanography Meteorological Satellite(COMS) has been retrieved since June 2010. The COMS OLR retrieval algorithms are based on regression analyses of radiative transfer simulations for spectral functions of COMS infrared channels. This study documents the accuracies of OLRs for future climate applications by making an intercomparison of four OLRs from one single-channel algorithm(OLR12.0using the 12.0 μm channel) and three multiple-channel algorithms(OLR10.8+12.0using the 10.8 and 12.0 μm channels; OLR6.7+10.8using the 6.7 and 10.8 μm channels; and OLR All using the 6.7, 10.8, and 12.0 μm channels). The COMS OLRs from these algorithms were validated with direct measurements of OLR from a broadband radiometer of the Clouds and Earth's Radiant Energy System(CERES) over the full COMS field of view [roughly(50°S–50°N, 70°–170°E)] during April 2011.Validation results show that the root-mean-square errors of COMS OLRs are 5–7 W m-2, which indicates good agreement with CERES OLR over the vast domain. OLR6.7+10.8and OLR All have much smaller errors(～ 6 W m-2) than OLR12.0and OLR10.8+12.0(～ 8 W m-2). Moreover, the small errors of OLR6.7+10.8and OLR All are systematic and can be readily reduced through additional mean bias correction and/or radiance calibration. These results indicate a noteworthy role of the6.7 μm water vapor absorption channel in improving the accuracy of the OLRs. The dependence of the accuracy of COMS OLRs on various surface, atmospheric, and observational conditions is also discussed.